Plants

18 pages, 6286 KiB

Open AccessEditor’s ChoiceArticle

Genetic Diversity of Fusarium oxysporum f. sp. cubense, the Fusarium Wilt Pathogen of Banana, in Ecuador

by Freddy Magdama, Lorena Monserrate-Maggi, Lizette Serrano, José García Onofre and María del Mar Jiménez-Gasco

Plants 2020, 9(9), 1133; https://doi.org/10.3390/plants9091133 - 1 Sep 2020

Cited by 14 | Viewed by 10837

Abstract

The continued dispersal of Fusarium oxysporum f. sp. cubense Tropical race 4 (FocTR4), a quarantine soil-borne pathogen that kills banana, has placed this worldwide industry on alert and triggered enormous pressure on National Plant Protection (NPOs) agencies to limit new incursions. [...] Read more.

The continued dispersal of Fusarium oxysporum f. sp. cubense Tropical race 4 (FocTR4), a quarantine soil-borne pathogen that kills banana, has placed this worldwide industry on alert and triggered enormous pressure on National Plant Protection (NPOs) agencies to limit new incursions. Accordingly, biosecurity plays an important role while long-term control strategies are developed. Aiming to strengthen the contingency response plan of Ecuador against FocTR4, a population biology study—including phylogenetics, mating type, vegetative compatibility group (VCG), and pathogenicity testing—was performed on isolates affecting local bananas, presumably associated with race 1 of F. oxysporum f. sp. cubense (Foc). Our results revealed that Foc populations in Ecuador comprise a single clonal lineage, associated with VCG0120. The lack of diversity observed in Foc populations is consistent with a single introduction event from which secondary outbreaks originated. The predominance of VCG0120, together with previous reports of its presence in Latin America countries, suggests this group as the main cause of the devastating Fusarium wilt epidemics that occurred in the 1950s associated to the demise of ‘Gros Michel’ bananas in the region. The isolates sampled from Ecuador caused disease in cultivars that are susceptible to races 1 and 2 under greenhouse experiments, although Fusarium wilt symptoms in the field were only found in ‘Gros Michel’. Isolates belonging to the same VCG0120 have historically caused disease on Cavendish cultivars in the subtropics. Overall, this study shows how Foc can be easily dispersed to other areas if restriction of contaminated materials is not well enforced. We highlight the need of major efforts on awareness and monitoring campaigns to analyze suspected cases and to contain potential first introduction events of FocTR4 in Ecuador. Full article

(This article belongs to the Collection Feature Papers in Plant Protection)

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13 pages, 2088 KiB

Open AccessEditor’s ChoiceArticle

Phytochemical, Cytotoxicity, Antioxidant and Anti-Inflammatory Effects of Psilocybe Natalensis Magic Mushroom

by Sanah M. Nkadimeng, Alice Nabatanzi, Christiaan M.L. Steinmann and Jacobus N. Eloff

Plants 2020, 9(9), 1127; https://doi.org/10.3390/plants9091127 - 31 Aug 2020

Cited by 34 | Viewed by 19707

Abstract

Psilocybin-containing mushrooms, commonly known as magic mushrooms, have been used since ancient and recent times for depression and to improve quality of life. However, their anti-inflammatory properties are not known. The study aims at investing cytotoxicity; antioxidant; and, for the first time, anti-inflammatory [...] Read more.

Psilocybin-containing mushrooms, commonly known as magic mushrooms, have been used since ancient and recent times for depression and to improve quality of life. However, their anti-inflammatory properties are not known. The study aims at investing cytotoxicity; antioxidant; and, for the first time, anti-inflammatory effects of Psilocybe natalensis, a psilocybin-containing mushroom that grows in South Africa, on lipopolysaccharide-induced RAW 264.7 macrophages. Macrophage cells were stimulated with lipopolysaccharide and treated with different concentrations of Psilocybe natalensis mushroom extracted with boiling hot water, cold water and ethanol over 24 h. Quercetin and N-nitro-L-arginine methyl ester were used as positive controls. Effects of extracts on the lipopolysaccharide-induced nitric oxide, prostaglandin E₂, and cytokine activities were investigated. Phytochemical analysis, and the antioxidant and cytotoxicity of extracts, were determined. Results showed that the three extracts inhibited the lipopolysaccharide-induced nitric oxide, prostaglandin E₂, and interleukin 1β cytokine production significantly in a dose-dependent manner close to that of the positive controls. A study proposed that ethanol and water extracts of Psilocybe natalensis mushroom were safe at concentrations used, and have antioxidant and anti-inflammatory effects. Phytochemical analysis confirmed the presence of natural antioxidant and anti-inflammatory compounds in the mushroom extracts. Full article

(This article belongs to the Special Issue Structural and Functional Analysis of Extracts in Plants)

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18 pages, 3034 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Toward Unifying Global Hotspots of Wild and Domesticated Biodiversity

by Samuel Pironon, James S. Borrell, Ian Ondo, Ruben Douglas, Charlotte Phillips, Colin K. Khoury, Michael B. Kantar, Nathan Fumia, Marybel Soto Gomez, Juan Viruel, Rafael Govaerts, Félix Forest and Alexandre Antonelli

Plants 2020, 9(9), 1128; https://doi.org/10.3390/plants9091128 - 31 Aug 2020

Cited by 30 | Viewed by 10543

Abstract

Global biodiversity hotspots are areas containing high levels of species richness, endemism and threat. Similarly, regions of agriculturally relevant diversity have been identified where many domesticated plants and animals originated, and co-occurred with their wild ancestors and relatives. The agro-biodiversity in these regions [...] Read more.

Global biodiversity hotspots are areas containing high levels of species richness, endemism and threat. Similarly, regions of agriculturally relevant diversity have been identified where many domesticated plants and animals originated, and co-occurred with their wild ancestors and relatives. The agro-biodiversity in these regions has, likewise, often been considered threatened. Biodiversity and agro-biodiversity hotspots partly overlap, but their geographic intricacies have rarely been investigated together. Here we review the history of these two concepts and explore their geographic relationship by analysing global distribution and human use data for all plants, and for major crops and associated wild relatives. We highlight a geographic continuum between agro-biodiversity hotspots that contain high richness in species that are intensively used and well known by humanity (i.e., major crops and most viewed species on Wikipedia) and biodiversity hotspots encompassing species that are less heavily used and documented (i.e., crop wild relatives and species lacking information on Wikipedia). Our contribution highlights the key considerations needed for further developing a unifying concept of agro-biodiversity hotspots that encompasses multiple facets of diversity (including genetic and phylogenetic) and the linkage with overall biodiversity. This integration will ultimately enhance our understanding of the geography of human-plant interactions and help guide the preservation of nature and its contributions to people. Full article

(This article belongs to the Special Issue Plant Biodiversity and Genetic Resources)

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16 pages, 748 KiB

Open AccessEditor’s ChoiceReview

Photosynthetic Traits and Nitrogen Uptake in Crops: Which Is the Role of Arbuscular Mycorrhizal Fungi?

by Raffaella Balestrini, Cecilia Brunetti, Walter Chitarra and Luca Nerva

Plants 2020, 9(9), 1105; https://doi.org/10.3390/plants9091105 - 27 Aug 2020

Cited by 42 | Viewed by 8478

Abstract

Arbuscular mycorrhizal (AM) fungi are root symbionts that provide mineral nutrients to the host plant in exchange for carbon compounds. AM fungi positively affect several aspects of plant life, improving nutrition and leading to a better growth, stress tolerance, and disease resistance and [...] Read more.

Arbuscular mycorrhizal (AM) fungi are root symbionts that provide mineral nutrients to the host plant in exchange for carbon compounds. AM fungi positively affect several aspects of plant life, improving nutrition and leading to a better growth, stress tolerance, and disease resistance and they interact with most crop plants such as cereals, horticultural species, and fruit trees. For this reason, they receive expanding attention for the potential use in sustainable and climate-smart agriculture context. Although several positive effects have been reported on photosynthetic traits in host plants, showing improved performances under abiotic stresses such as drought, salinity and extreme temperature, the involved mechanisms are still to be fully discovered. In this review, some controversy aspects related to AM symbiosis and photosynthesis performances will be discussed, with a specific focus on nitrogen acquisition-mediated by AM fungi. Full article

(This article belongs to the Special Issue Selected Papers from the International Conference on Biophysics of Photosynthesis: From molecules to the field)

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18 pages, 3454 KiB

Open AccessEditor’s ChoiceArticle

Comparative Metabolomics Profiling of Polyphenols, Nutrients and Antioxidant Activities of Two Red Onion (Allium cepa L.) Cultivars

by Rita Metrani, Jashbir Singh, Pratibha Acharya, Guddadarangavvanahally K. Jayaprakasha and Bhimanagouda S. Patil

Plants 2020, 9(9), 1077; https://doi.org/10.3390/plants9091077 - 21 Aug 2020

Cited by 45 | Viewed by 6622

Abstract

Onion is among the most widely cultivated and consumed economic crops. Onions are an excellent dietary source of polyphenols and nutrients. However, onions phytonutrient compositions vary with cultivars and growing locations. Therefore, the present study involved the evaluation of polyphenol, nutritional composition (proteins, [...] Read more.

Onion is among the most widely cultivated and consumed economic crops. Onions are an excellent dietary source of polyphenols and nutrients. However, onions phytonutrient compositions vary with cultivars and growing locations. Therefore, the present study involved the evaluation of polyphenol, nutritional composition (proteins, nitrogen, and minerals), sugars, pyruvate, antioxidant, and α-amylase inhibition activities of red onion cultivars, sweet Italian, and honeysuckle grown in California and Texas, respectively. The total flavonoid for honeysuckle and sweet Italian was 449 and 345 μg/g FW, respectively. The total anthocyanin for honeysuckle onion was 103 μg/g FW, while for sweet Italian onion was 86 μg/g FW. Cyanidin-3-(6”-malonoylglucoside) and cyanidin-3-(6”-malonoyl-laminaribioside) were the major components in both the cultivars. The pungency of red onions in honeysuckle ranged between 4.9 and 7.9 μmoL/mL, whereas in sweet Italian onion ranged from 8.3 to 10 μmoL/mL. The principal component analysis was applied to determine the most important variables that separate the cultivars of red onion. Overall results indicated that total flavonoids, total phenolic content, total anthocyanins, protein, and calories for honeysuckle onions were higher than the sweet Italian onions. These results could provide information about high quality and adding value to functional food due to the phytochemicals and nutritional composition of red onions. Full article

(This article belongs to the Special Issue Mechanisms of Plant Antioxidants Action)

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21 pages, 4314 KiB

Open AccessEditor’s ChoiceReview

Subcellular Roles of Glutathione in Mediating Plant Defense during Biotic Stress

by Bernd Zechmann

Plants 2020, 9(9), 1067; https://doi.org/10.3390/plants9091067 - 20 Aug 2020

Cited by 67 | Viewed by 5059

Abstract

Glutathione and reactive oxygen species (ROS) play important roles, within different cell compartments, in activating plant defense and the development of resistance. In mitochondria, the accumulation of ROS and the change of glutathione towards its oxidized state leads to mitochondrial dysfunction, activates cell [...] Read more.

Glutathione and reactive oxygen species (ROS) play important roles, within different cell compartments, in activating plant defense and the development of resistance. In mitochondria, the accumulation of ROS and the change of glutathione towards its oxidized state leads to mitochondrial dysfunction, activates cell death, and triggers resistance. The accumulation of glutathione in chloroplasts and peroxisomes at the early stages of plant pathogen interactions is related to increased tolerance and resistance. The collapse of the antioxidative system in these two cell compartments at the later stages leads to cell death through retrograde signaling. The cytosol can be considered to be the switchboard during biotic stress where glutathione is synthesized, equally distributed to, and collected from different cell compartments. Changes in the redox state of glutathione and the accumulation of ROS in the cytosol during biotic stress can initiate the activation of defense genes in nuclei through pathways that involve salicylic acid, jasmonic acid, auxins, and abscisic acid. This review dissects the roles of glutathione in individual organelles during compatible and incompatible bacterial, fungal, and viral diseases in plants and explores the subcelluar roles of ROS, glutathione, ascorbate, and related enzymes in the development of resistance. Full article

(This article belongs to the Special Issue Mechanisms of Resistance to Plant Diseases)

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33 pages, 1359 KiB

Open AccessEditor’s ChoiceReview

Artemisia absinthium L.—Importance in the History of Medicine, the Latest Advances in Phytochemistry and Therapeutical, Cosmetological and Culinary Uses

by Agnieszka Szopa, Joanna Pajor, Paweł Klin, Agnieszka Rzepiela, Hosam O. Elansary, Fahed A. Al-Mana, Mohamed A. Mattar and Halina Ekiert

Plants 2020, 9(9), 1063; https://doi.org/10.3390/plants9091063 - 19 Aug 2020

Cited by 80 | Viewed by 23579

Abstract

Artemisia absinthium—wormwood (Asteraceae)—is a very important species in the history of medicine, formerly described in medieval Europe as “the most important master against all exhaustions”. It is a species known as a medicinal plant in Europe and also in West [...] Read more.

Artemisia absinthium—wormwood (Asteraceae)—is a very important species in the history of medicine, formerly described in medieval Europe as “the most important master against all exhaustions”. It is a species known as a medicinal plant in Europe and also in West Asia and North America. The raw material obtained from this species is Absinthii herba and Artemisiae absinthii aetheroleum. The main substances responsible for the biological activity of the herb are: the essential oil, bitter sesquiterpenoid lactones, flavonoids, other bitterness-imparting compounds, azulenes, phenolic acids, tannins and lignans. In the official European medicine, the species is used in both allopathy and homeopathy. In the traditional Asian and European medicine, it has been used as an effective agent in gastrointestinal ailments and also in the treatment of helminthiasis, anaemia, insomnia, bladder diseases, difficult-to-heal wounds, and fever. Today, numerous other directions of biological activity of the components of this species have been demonstrated and confirmed by scientific research, such as antiprotozoal, antibacterial, antifungal, anti-ulcer, hepatoprotective, anti-inflammatory, immunomodulatory, cytotoxic, analgesic, neuroprotective, anti-depressant, procognitive, neurotrophic, and cell membrane stabilizing and antioxidant activities. A. absinthium is also making a successful career as a cosmetic plant. In addition, the importance of this species as a spice plant and valuable additive in the alcohol industry (famous absinthe and vermouth-type wines) has not decreased. The species has also become an object of biotechnological research. Full article

(This article belongs to the Collection Bioactive Compounds in Plants)

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15 pages, 2595 KiB

Open AccessEditor’s ChoiceArticle

Jasmonate Signalling Contributes to Primary Root Inhibition Upon Oxygen Deficiency in Arabidopsis thaliana

by Vinay Shukla, Lara Lombardi, Ales Pencik, Ondrej Novak, Daan A. Weits, Elena Loreti, Pierdomenico Perata, Beatrice Giuntoli and Francesco Licausi

Plants 2020, 9(8), 1046; https://doi.org/10.3390/plants9081046 - 17 Aug 2020

Cited by 21 | Viewed by 4991

Abstract

Plants, including most crops, are intolerant to waterlogging, a stressful condition that limits the oxygen available for roots, thereby inhibiting their growth and functionality. Whether root growth inhibition represents a preventive measure to save energy or is rather a consequence of reduced metabolic [...] Read more.

Plants, including most crops, are intolerant to waterlogging, a stressful condition that limits the oxygen available for roots, thereby inhibiting their growth and functionality. Whether root growth inhibition represents a preventive measure to save energy or is rather a consequence of reduced metabolic rates has yet to be elucidated. In the present study, we gathered evidence for hypoxic repression of root meristem regulators that leads to root growth inhibition. We also explored the contribution of the hormone jasmonic acid (JA) to this process in Arabidopsis thaliana. Analysis of transcriptomic profiles, visualisation of fluorescent reporters and direct hormone quantification confirmed the activation of JA signalling under hypoxia in the roots. Further, root growth assessment in JA-related mutants in aerobic and anaerobic conditions indicated that JA signalling components contribute to active root inhibition under hypoxia. Finally, we show that the oxygen-sensing transcription factor (TF) RAP2.12 can directly induce Jasmonate Zinc-finger proteins (JAZs), repressors of JA signalling, to establish feedback inhibition. In summary, our study sheds new light on active root growth restriction under hypoxic conditions and on the involvement of the JA hormone in this process and its cross talk with the oxygen sensing machinery of higher plants. Full article

(This article belongs to the Special Issue Plant Responses to Hypoxia)

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18 pages, 1785 KiB

Open AccessEditor’s ChoiceReview

Canthaxanthin, a Red-Hot Carotenoid: Applications, Synthesis, and Biosynthetic Evolution

by Bárbara A. Rebelo, Sara Farrona, M. Rita Ventura and Rita Abranches

Plants 2020, 9(8), 1039; https://doi.org/10.3390/plants9081039 - 15 Aug 2020

Cited by 56 | Viewed by 6156

Abstract

Carotenoids are a class of pigments with a biological role in light capture and antioxidant activities. High value ketocarotenoids, such as astaxanthin and canthaxanthin, are highly appealing for applications in human nutraceutical, cosmetic, and animal feed industries due to their color- and health-related [...] Read more.

Carotenoids are a class of pigments with a biological role in light capture and antioxidant activities. High value ketocarotenoids, such as astaxanthin and canthaxanthin, are highly appealing for applications in human nutraceutical, cosmetic, and animal feed industries due to their color- and health-related properties. In this review, recent advances in metabolic engineering and synthetic biology towards the production of ketocarotenoids, in particular the red-orange canthaxanthin, are highlighted. Also reviewed and discussed are the properties of canthaxanthin, its natural producers, and various strategies for its chemical synthesis. We review the de novo synthesis of canthaxanthin and the functional β-carotene ketolase enzyme across organisms, supported by a protein-sequence-based phylogenetic analysis. Various possible modifications of the carotenoid biosynthesis pathway and the present sustainable cost-effective alternative platforms for ketocarotenoids biosynthesis are also discussed. Full article

(This article belongs to the Special Issue Plant Molecular Farming)

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16 pages, 2836 KiB

Open AccessEditor’s ChoiceArticle

A GATA Transcription Factor from Soybean (Glycine max) Regulates Chlorophyll Biosynthesis and Suppresses Growth in the Transgenic Arabidopsis thaliana

by Chanjuan Zhang, Yi Huang, Zhiyuan Xiao, Hongli Yang, Qingnan Hao, Songli Yuan, Haifeng Chen, Limiao Chen, Shuilian Chen, Xinan Zhou and Wenjun Huang

Plants 2020, 9(8), 1036; https://doi.org/10.3390/plants9081036 - 15 Aug 2020

Cited by 30 | Viewed by 4329

Abstract

Chlorophyll plays an essential role in photosynthetic light harvesting and energy transduction in green tissues of higher plants and is closely related to photosynthesis and crop yield. Identification of transcription factors (TFs) involved in regulating chlorophyll biosynthesis is still limited in soybean ( [...] Read more.

Chlorophyll plays an essential role in photosynthetic light harvesting and energy transduction in green tissues of higher plants and is closely related to photosynthesis and crop yield. Identification of transcription factors (TFs) involved in regulating chlorophyll biosynthesis is still limited in soybean (Glycine max), and the previously identified GmGATA58 is suggested to potentially modulate chlorophyll and nitrogen metabolisms, but its complete function is still unknown. In this study, subcellular localization assay showed that GmGATA58 was localized in the nucleus. Histochemical GUS assay and qPCR assay indicated that GmGATA58 was mainly expressed in leaves and responded to nitrogen, light and phytohormone treatments. Overexpression of GmGATA58 in the Arabidopsis thaliana ortholog AtGATA21 (gnc) mutant complemented the greening defect, while overexpression in Arabidopsis wild-type led to increasing chlorophyll content in leaves through up-regulating the expression levels of the large of chlorophyll biosynthetic pathway genes, but suppressing plant growth and yield, although the net photosynthetic rate was slightly improved. Dual-luciferase reporter assay also supported that GmGATA58 activated the transcription activities of three promoters of key chlorophyll biosynthetic genes of soybean in transformed protoplast of Arabidopsis. It is concluded that GmGATA58 played an important role in regulating chlorophyll biosynthesis, but suppressed plant growth and yield in transgenic Arabidopsis. Full article

(This article belongs to the Section Plant Physiology and Metabolism)

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22 pages, 1334 KiB

Open AccessEditor’s ChoiceReview

Exploiting Biological Nitrogen Fixation: A Route Towards a Sustainable Agriculture

by Abdoulaye Soumare, Abdala G. Diedhiou, Moses Thuita, Mohamed Hafidi, Yedir Ouhdouch, Subramaniam Gopalakrishnan and Lamfeddal Kouisni

Plants 2020, 9(8), 1011; https://doi.org/10.3390/plants9081011 - 11 Aug 2020

Cited by 197 | Viewed by 23507

Abstract

For all living organisms, nitrogen is an essential element, while being the most limiting in ecosystems and for crop production. Despite the significant contribution of synthetic fertilizers, nitrogen requirements for food production increase from year to year, while the overuse of agrochemicals compromise [...] Read more.

For all living organisms, nitrogen is an essential element, while being the most limiting in ecosystems and for crop production. Despite the significant contribution of synthetic fertilizers, nitrogen requirements for food production increase from year to year, while the overuse of agrochemicals compromise soil health and agricultural sustainability. One alternative to overcome this problem is biological nitrogen fixation (BNF). Indeed, more than 60% of the fixed N on Earth results from BNF. Therefore, optimizing BNF in agriculture is more and more urgent to help meet the demand of the food production needs for the growing world population. This optimization will require a good knowledge of the diversity of nitrogen-fixing microorganisms, the mechanisms of fixation, and the selection and formulation of efficient N-fixing microorganisms as biofertilizers. Good understanding of BNF process may allow the transfer of this ability to other non-fixing microorganisms or to non-leguminous plants with high added value. This minireview covers a brief history on BNF, cycle and mechanisms of nitrogen fixation, biofertilizers market value, and use of biofertilizers in agriculture. The minireview focuses particularly on some of the most effective microbial products marketed to date, their efficiency, and success-limiting in agriculture. It also highlights opportunities and difficulties of transferring nitrogen fixation capacity in cereals. Full article

(This article belongs to the Special Issue The Rhizobium-Legume Symbiosis)

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27 pages, 12025 KiB

Open AccessEditor’s ChoiceArticle

Comparative and Functional Screening of Three Species Traditionally used as Antidepressants: Valeriana officinalis L., Valeriana jatamansi Jones ex Roxb. and Nardostachys jatamansi (D.Don) DC.

by Laura Cornara, Gabriele Ambu, Domenico Trombetta, Marcella Denaro, Susanna Alloisio, Jessica Frigerio, Massimo Labra, Govinda Ghimire, Marco Valussi and Antonella Smeriglio

Plants 2020, 9(8), 994; https://doi.org/10.3390/plants9080994 - 5 Aug 2020

Cited by 16 | Viewed by 7358

Abstract

The essential oils (EOs) of three Caprifoliaceae species, the Eurasiatic Valeriana officinalis (Vo), the Himalayan Valeriana jatamansi (Vj) and Nardostachys jatamansi (Nj), are traditionally used to treat neurological disorders. Roots/rhizomes micromorphology, DNA barcoding and EOs phytochemical characterization were carried out, while biological effects [...] Read more.

The essential oils (EOs) of three Caprifoliaceae species, the Eurasiatic Valeriana officinalis (Vo), the Himalayan Valeriana jatamansi (Vj) and Nardostachys jatamansi (Nj), are traditionally used to treat neurological disorders. Roots/rhizomes micromorphology, DNA barcoding and EOs phytochemical characterization were carried out, while biological effects on the nervous system were assessed by acetylcholinesterase (AChE) inhibitory activity and microelectrode arrays (MEA). Nj showed the highest inhibitory activity on AChE (IC₅₀ 67.15 μg/mL) followed by Vo (IC₅₀ 127.30 μg/mL) and Vj (IC₅₀ 246.84 μg/mL). MEA analyses on rat cortical neurons, carried out by recording mean firing rate (MFR) and mean bursting rate (MBR), revealed stronger inhibition by Nj (IC₅₀ 18.8 and 11.1 μg/mL) and Vo (16.5 and 22.5 μg/mL), compared with Vj (68.5 and 89.3 μg/mL). These results could be related to different EO compositions, since sesquiterpenes and monoterpenes significantly contribute to the observed effects, but the presence of oxygenated compounds such as aldehydes and ketones is a discriminating factor in determining the order of potency. Our multidisciplinary approach represents an important tool to avoid the adulteration of herbal drugs and permits the evaluation of the effectiveness of EOs that could be used for a wide range of therapeutic applications. Full article

(This article belongs to the Collection Bioactive Compounds in Plants)

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16 pages, 740 KiB

Open AccessEditor’s ChoiceReview

Osmotin: A Cationic Protein Leads to Improve Biotic and Abiotic Stress Tolerance in Plants

by Muhammad Ajmal Bashir, Cristian Silvestri, Touqeer Ahmad, Ishfaq Ahmad Hafiz, Nadeem Akhtar Abbasi, Ayesha Manzoor, Valerio Cristofori and Eddo Rugini

Plants 2020, 9(8), 992; https://doi.org/10.3390/plants9080992 - 4 Aug 2020

Cited by 43 | Viewed by 5674

Abstract

Research on biologically active compounds has been increased in order to improve plant protection against various environmental stresses. Among natural sources, plants are the fundamental material for studying these bioactive compounds as their immune system consists of many peptides, proteins, and hormones. Osmotin [...] Read more.

Research on biologically active compounds has been increased in order to improve plant protection against various environmental stresses. Among natural sources, plants are the fundamental material for studying these bioactive compounds as their immune system consists of many peptides, proteins, and hormones. Osmotin is a multifunctional stress-responsive protein belonging to pathogenesis-related 5 (PR-5) defense-related protein family, which is involved in inducing osmo-tolerance in plants. In this scenario, the accumulation of osmotin initiates abiotic and biotic signal transductions. These proteins work as antifungal agents against a broad range of fungal species by increasing plasma membrane permeability and dissipating the membrane potential of infecting fungi. Therefore, overexpression of tobacco osmotin protein in transgenic plants protects them from different stresses by reducing reactive oxygen species (ROS) production, limiting lipid peroxidation, initiating programmed cell death (PCD), and increasing proline content and scavenging enzyme activity. Other than osmotin, its homologous proteins, osmotin-like proteins (OLPs), also have dual function in plant defense against osmotic stress and have strong antifungal activity. Full article

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17 pages, 1054 KiB

Open AccessEditor’s ChoiceReview

Amino Acid Transporters in Plants: Identification and Function

by Xuehui Yao, Jing Nie, Ruoxue Bai and Xiaolei Sui

Plants 2020, 9(8), 972; https://doi.org/10.3390/plants9080972 - 31 Jul 2020

Cited by 70 | Viewed by 9988

Abstract

Amino acid transporters are the main mediators of nitrogen distribution throughout the plant body, and are essential for sustaining growth and development. In this review, we summarize the current state of knowledge on the identity and biological functions of amino acid transporters in [...] Read more.

Amino acid transporters are the main mediators of nitrogen distribution throughout the plant body, and are essential for sustaining growth and development. In this review, we summarize the current state of knowledge on the identity and biological functions of amino acid transporters in plants, and discuss the regulation of amino acid transporters in response to environmental stimuli. We focus on transporter function in amino acid assimilation and phloem loading and unloading, as well as on the molecular identity of amino acid exporters. Moreover, we discuss the effects of amino acid transport on carbon assimilation, as well as their cross-regulation, which is at the heart of sustainable agricultural production. Full article

(This article belongs to the Special Issue Amino Acid Translocation, Transport and Transporters in Plants)

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17 pages, 790 KiB

Open AccessEditor’s ChoiceReview

Amino Acid Transporters in Plant Cells: A Brief Review

by Guangzhe Yang, Qiuxing Wei, Hao Huang and Jixing Xia

Plants 2020, 9(8), 967; https://doi.org/10.3390/plants9080967 - 30 Jul 2020

Cited by 65 | Viewed by 9732

Abstract

Amino acids are not only a nitrogen source that can be directly absorbed by plants, but also the major transport form of organic nitrogen in plants. A large number of amino acid transporters have been identified in different plant species. Despite belonging to [...] Read more.

Amino acids are not only a nitrogen source that can be directly absorbed by plants, but also the major transport form of organic nitrogen in plants. A large number of amino acid transporters have been identified in different plant species. Despite belonging to different families, these amino acid transporters usually exhibit some general features, such as broad expression pattern and substrate selectivity. This review mainly focuses on transporters involved in amino acid uptake, phloem loading and unloading, xylem-phloem transfer, import into seed and intracellular transport in plants. We summarize the other physiological roles mediated by amino acid transporters, including development regulation, abiotic stress tolerance and defense response. Finally, we discuss the potential applications of amino acid transporters for crop genetic improvement. Full article

(This article belongs to the Special Issue Amino Acid Translocation, Transport and Transporters in Plants)

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26 pages, 1312 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Main Challenges and Actions Needed to Improve Conservation and Sustainable Use of Our Crop Wild Relatives

by Johannes M. M. Engels and Imke Thormann

Plants 2020, 9(8), 968; https://doi.org/10.3390/plants9080968 - 30 Jul 2020

Cited by 33 | Viewed by 5400

Abstract

Crop wild relatives (CWR, plural CWRs) are those wild species that are regarded as the ancestors of our cultivated crops. It was only at the end of the last century that they were accorded a high priority for their conservation and, thus, for [...] Read more.

Crop wild relatives (CWR, plural CWRs) are those wild species that are regarded as the ancestors of our cultivated crops. It was only at the end of the last century that they were accorded a high priority for their conservation and, thus, for many genebanks, they are a new and somewhat unknown set of plant genetic resources for food and agriculture. After defining and characterizing CWR and their general threat status, providing an assessment of biological peculiarities of CWR with respect to conservation management, illustrating the need for prioritization and addressing the importance of data and information, we made a detailed assessment of specific aspects of CWRs of direct relevance for their conservation and use. This assessment was complemented by an overview of the current status of CWRs conservation and use, including facts and figures on the in situ conservation, on the ex situ conservation in genebanks and botanic gardens, as well as of the advantages of a combination of in situ and ex situ conservation, the so-called complementary conservation approach. In addition, a brief assessment of the situation with respect to the use of CWRs was made. From these assessments we derived the needs for action in order to achieve a more effective and efficient conservation and use, specifically with respect to the documentation of CWRs, their in situ and ex situ, as well as their complementarity conservation, and how synergies between these components can be obtained. The review was concluded with suggestions on how use can be strengthened, as well as the conservation system at large at the local, national, and regional/international level. Finally, based on the foregoing assessments, a number of recommendations were elaborated on how CWRs can be better conserved and used in order to exploit their potential benefits more effectively. Full article

(This article belongs to the Special Issue Plant Biodiversity and Genetic Resources)

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13 pages, 3488 KiB

Open AccessEditor’s ChoiceArticle

Physiological Characteristics of Photosynthesis in Yellow-Green, Green and Dark-Green Chinese Kale (Brassica oleracea L. var. alboglabra Musil.) under Varying Light Intensities

by Kuan-Hung Lin, Feng-Chi Shih, Meng-Yuan Huang and Jen-Hsien Weng

Plants 2020, 9(8), 960; https://doi.org/10.3390/plants9080960 - 30 Jul 2020

Cited by 18 | Viewed by 4247

Abstract

The objective of this work was to study physiological characteristics and photosynthetic apparatus in differentially pigmented leaves of three Chinese kale cultivars. Chlorophyll (Chl) fluorescence and photochemical reflectance index (PRI) measurements in green, yellow-green, and dark-green cultivars in response to varying light intensities. [...] Read more.

The objective of this work was to study physiological characteristics and photosynthetic apparatus in differentially pigmented leaves of three Chinese kale cultivars. Chlorophyll (Chl) fluorescence and photochemical reflectance index (PRI) measurements in green, yellow-green, and dark-green cultivars in response to varying light intensities. As light intensity increased from 200 to 2000 photosynthetic photon flux density (PPFD), fraction of light absorbed in photosystem (PS) II and PRI values in all plants were strongly lowered, but fraction of light absorbed in PSII dissipated via thermal energy dissipation and non-photochemical quenching (NPQ) values in all plants wereremarkably elevated.When plants were exposed to 200 PPFD, the values of fraction of light absorbed in PSII, utilized in photosynthetic electron transport(p), andfraction of light absorbed excitation energy in PSII dissipated via thermal energy dissipation (D), remained stable regardless of the changes in levels of Chla + b. Under 800 and 1200 PPFD, the values of p and electron transport rate (ETR) decreased, but D and NPQ increased as Chla + bcontent decreased, suggesting that decrease inChla + bcontent led to lower PSII efficiency and it became necessary to increase dissipate excess energy. On the contrary, in 2000 PPFD, leaves with lower Chla + bcontent had relatively higher p and electron transport rate (ETR) values and lower D level, as well as tended to increase more in NPQ but decrease more in PRI values. The consistent relations between PRI and NPQ suggest that NPQ is mainly consisted ofthe xanthophyll cycle-dependentenergy quenching.Yellow-green cultivar showed lower Chla + bcontent but high carotenoids/Chla + b ratio and had high light protection ability under high PPFD. The precise management of photosynthetic parameters in response to light intensity can maximize the growth and development of Chinese kale plants. Full article

(This article belongs to the Special Issue Adaptation of Plants to Environmental Changes: Light and Temperature in Plant Development)

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29 pages, 1103 KiB

Open AccessEditor’s ChoiceReview

A Review on Applications and Uses of Thymus in the Food Industry

by Gema Nieto

Plants 2020, 9(8), 961; https://doi.org/10.3390/plants9080961 - 30 Jul 2020

Cited by 126 | Viewed by 11816

Abstract

Thyme is one of the most important medicinal plants because of its ethnopharmacological relevance and high content of bioactive compounds. This review focuses particularly on thyme as an alternative natural antioxidant and antimicrobial with potential use in the food industry. This is in [...] Read more.

Thyme is one of the most important medicinal plants because of its ethnopharmacological relevance and high content of bioactive compounds. This review focuses particularly on thyme as an alternative natural antioxidant and antimicrobial with potential use in the food industry. This is in line with the preferences of the current consumer, who demands healthier and more natural products. Different studies have concluded that the use of thyme increases stability and reduces lipid oxidation during the shelf-life period of foods (meat, meat products, milk, fish or fish products), which makes thyme a promising source of natural additives. Despite these findings, the use of Thymus extracts or essential oils as natural additives in foods is reduced in comparison with other natural preservative extracts. This review provides an overview of the most important information on the positive effect of the bioactive compounds of thyme and its uses as a preservative in foods, taking into account its origin (from plants, plant extracts or essential oils). Full article

(This article belongs to the Special Issue Natural Products from Plant-Derived as Preservatives)

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15 pages, 835 KiB

Open AccessEditor’s ChoiceArticle

Utilization Pattern of Indigenous and Naturalized Plants among Some Selected Rural Households of North West Province, South Africa

by Abiodun Olusola Omotayo, Peter Tshepiso Ndhlovu, Seleke Christopher Tshwene and Adeyemi Oladapo Aremu

Plants 2020, 9(8), 953; https://doi.org/10.3390/plants9080953 - 28 Jul 2020

Cited by 22 | Viewed by 4723

Abstract

Globally, a substantial proportion of existing indigenous and naturalized foods are often neglected thereby narrowing the food-base available to humans. The current study explored the use and contribution of indigenous and naturalized plants to the households’ food-pool among 12 communities in the North [...] Read more.

Globally, a substantial proportion of existing indigenous and naturalized foods are often neglected thereby narrowing the food-base available to humans. The current study explored the use and contribution of indigenous and naturalized plants to the households’ food-pool among 12 communities in the North West Province of South Africa. An ethnobotanical survey was conducted among 133 rural households across the 12 selected communities from the four district municipalities in North West Province, South Africa. We analyzed the utilization patterns for 31 selected indigenous and naturalized plants (grains, fruits, and vegetables) among the 133 households using two ethnobotanical indices. In reference to the checklist of 31 plants, the sampled households utilize approximately 94% (29) as staple foods, beverages, fruits and fodder. Sorghum bicolor, Vigna unguiculata, Amaranthus sp., Sclerocarya birrea, Persea americana, and Mimusops zeyheri were among the top-six plants based on the Relative Frequency of Citation (RFC, 40–83%). In terms of the different crop-types, Sorghum bicolor (grain), Amaranthus sp. (vegetable), and Sclerocarya birrea (fruit) were the top-ranked plants based on the Species Popularity Index (SPI, 0.53–0.83) among the participants. Overall, there is a need for a renaissance of indigenous and naturalized plants, which has the potential to encourage rural farmers to further embrace the cultivation of these plants on a larger scale so as to enhance food security in the rural communities. Full article

(This article belongs to the Special Issue Insights into Ethnobotanical Research: Linking Tradition, Innovation, and Sustainability)

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22 pages, 1577 KiB

Open AccessEditor’s ChoiceReview

Bioactive Compounds and Bioactivities of Brassica oleracea L. var. Italica Sprouts and Microgreens: An Updated Overview from a Nutraceutical Perspective

by Thanh Ninh Le, Chiu-Hsia Chiu and Pao-Chuan Hsieh

Plants 2020, 9(8), 946; https://doi.org/10.3390/plants9080946 - 27 Jul 2020

Cited by 71 | Viewed by 10286

Abstract

Sprouts and microgreens, the edible seedlings of vegetables and herbs, have received increasing attention in recent years and are considered as functional foods or superfoods owing to their valuable health-promoting properties. In particular, the seedlings of broccoli (Brassica oleracea L. var. Italica [...] Read more.

Sprouts and microgreens, the edible seedlings of vegetables and herbs, have received increasing attention in recent years and are considered as functional foods or superfoods owing to their valuable health-promoting properties. In particular, the seedlings of broccoli (Brassica oleracea L. var. Italica) have been highly prized for their substantial amount of bioactive constituents, including glucosinolates, phenolic compounds, vitamins, and essential minerals. These secondary metabolites are positively associated with potential health benefits. Numerous in vitro and in vivo studies demonstrated that broccoli seedlings possess various biological properties, including antioxidant, anticancer, anticancer, antimicrobial, anti-inflammatory, anti-obesity and antidiabetic activities. The present review summarizes the updated knowledge about bioactive compounds and bioactivities of these broccoli products and discusses the relevant mechanisms of action. This review will serve as a potential reference for food selections of consumers and applications in functional food and nutraceutical industries. Full article

(This article belongs to the Special Issue Natural Compounds–Successful Solutions for the Medical Challenges of the 21st Century)

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25 pages, 1187 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Recent Advances of In Vitro Culture for the Application of New Breeding Techniques in Citrus

by Lara Poles, Concetta Licciardello, Gaetano Distefano, Elisabetta Nicolosi, Alessandra Gentile and Stefano La Malfa

Plants 2020, 9(8), 938; https://doi.org/10.3390/plants9080938 - 24 Jul 2020

Cited by 25 | Viewed by 5450

Abstract

Citrus is one of the most important fruit crops in the world. This review will discuss the recent findings related to citrus transformation and regeneration protocols of juvenile and adult explants. Despite the many advances that have been made in the last years [...] Read more.

Citrus is one of the most important fruit crops in the world. This review will discuss the recent findings related to citrus transformation and regeneration protocols of juvenile and adult explants. Despite the many advances that have been made in the last years (including the use of inducible promoters and site-specific recombination systems), transformation efficiency, and regeneration potential still represent a bottleneck in the application of the new breeding techniques in commercial citrus varieties. The influence of genotype, explant type, and other factors affecting the regeneration and transformation of the most used citrus varieties will be described, as well as some examples of how these processes can be applied to improve fruit quality and resistance to various pathogens and pests, including the potential of using genome editing in citrus. The availability of efficient regeneration and transformation protocols, together with the availability of the source of resistance, is made even more important in light of the fast diffusion of emerging diseases, such as Huanglongbing (HLB), which is seriously challenging citriculture worldwide. Full article

(This article belongs to the Special Issue Advances in Genetic Engineering Strategies for Fruit Crop Breeding)

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16 pages, 3375 KiB

Open AccessEditor’s ChoiceReview

Photoreceptors Regulate Plant Developmental Plasticity through Auxin

by Jesse J. Küpers, Lisa Oskam and Ronald Pierik

Plants 2020, 9(8), 940; https://doi.org/10.3390/plants9080940 - 24 Jul 2020

Cited by 44 | Viewed by 10221

Abstract

Light absorption by plants changes the composition of light inside vegetation. Blue (B) and red (R) light are used for photosynthesis whereas far-red (FR) and green light are reflected. A combination of UV-B, blue and R:FR-responsive photoreceptors collectively measures the light and temperature [...] Read more.

Light absorption by plants changes the composition of light inside vegetation. Blue (B) and red (R) light are used for photosynthesis whereas far-red (FR) and green light are reflected. A combination of UV-B, blue and R:FR-responsive photoreceptors collectively measures the light and temperature environment and adjusts plant development accordingly. This developmental plasticity to photoreceptor signals is largely regulated through the phytohormone auxin. The phytochrome, cryptochrome and UV Resistance Locus 8 (UVR8) photoreceptors are inactivated in shade and/or elevated temperature, which releases their repression of Phytochrome Interacting Factor (PIF) transcription factors. Active PIFs stimulate auxin synthesis and reinforce auxin signalling responses through direct interaction with Auxin Response Factors (ARFs). It was recently discovered that shade-induced hypocotyl elongation and petiole hyponasty depend on long-distance auxin transport towards target cells from the cotyledon and leaf tip, respectively. Other responses, such as phototropic bending, are regulated by auxin transport and signalling across only a few cell layers. In addition, photoreceptors can directly interact with components in the auxin signalling pathway, such as Auxin/Indole Acetic Acids (AUX/IAAs) and ARFs. Here we will discuss the complex interactions between photoreceptor and auxin signalling, addressing both mechanisms and consequences of these highly interconnected pathways. Full article

(This article belongs to the Special Issue Advances in Auxin Research)

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19 pages, 3760 KiB

Open AccessEditor’s ChoiceArticle

Changes in the Content of Some Groups of Phenolic Compounds and Biological Activity of Extracts of Various Parts of Heather (Calluna vulgaris (L.) Hull) at Different Growth Stages

by Victoria Chepel, Valery Lisun and Liubov Skrypnik

Plants 2020, 9(8), 926; https://doi.org/10.3390/plants9080926 - 22 Jul 2020

Cited by 36 | Viewed by 5515

Abstract

Heather (Calluna vulgaris (L.) Hull.) is noted for a diverse chemical composition and a broad range of biological activity. The current study was aimed at monitoring changes in the accumulation of certain groups of phenolic compounds in various organs of heather (leaves, [...] Read more.

Heather (Calluna vulgaris (L.) Hull.) is noted for a diverse chemical composition and a broad range of biological activity. The current study was aimed at monitoring changes in the accumulation of certain groups of phenolic compounds in various organs of heather (leaves, stems, roots, rhizomes, flowers, and seeds) at different growth stages (vegetative, floral budding, flowering, and seed ripening) as well as studying antioxidant (employing the DPPH and FRAP assays) and antibacterial activity of its extracts. The highest total amount of phenolic compounds, tannins, flavonoids, hydroxycinnamic acids, and proanthocyanidins was detected in leaves and roots at all growth stages, except for the flowering stage. At the flowering stage, the highest content of some groups of phenolic compounds (flavonoids, proanthocyanidins, and anthocyanins) was observed in flowers. Highest antioxidant activity was recorded for the flower extracts (about 500 mg of ascorbic acid equivalents per gram according to the DPPH assay) and for the leaf extract at the ripening stage (about 350 mg of ascorbic acid equivalents per gram according to the FRAP assay). Strong correlation was noted between antioxidant activity (DPPH) and the content of anthocyanins (r = 0.75, p ≤ 0.01) as well as between antioxidant activity (FRAP) and the total content of phenolic compounds (r = 0.77, p ≤ 0.01). Leaf extracts and stem extracts turned out to perform antibacterial action against both gram-negative and gram-positive bacteria, whereas root extracts appeared to be active only against B. subtilis, and rhizome extracts against E. coli. Full article

(This article belongs to the Collection Bioactive Compounds in Plants)

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14 pages, 3642 KiB

Open AccessEditor’s ChoiceCommunication

A Critical Cross-Species Comparison of Pollen from Nelumbo nucifera Gaertn. vs. Nymphaea lotus L. for Authentication of Thai Medicinal Herbal Tea

by Duangjai Tungmunnithum, Sullivan Renouard, Samantha Drouet, Jean-Philippe Blondeau and Christophe Hano

Plants 2020, 9(7), 921; https://doi.org/10.3390/plants9070921 - 21 Jul 2020

Cited by 26 | Viewed by 4503

Abstract

“Bau Luang” or Nelumbo nucifera Gaertn. is an aquatic medicinal herb that has been used as a component of traditional medicines, medicinal products, and herbal tea for good health, particularly in Asia. The stamen of N. nucifera is an important part of this [...] Read more.

“Bau Luang” or Nelumbo nucifera Gaertn. is an aquatic medicinal herb that has been used as a component of traditional medicines, medicinal products, and herbal tea for good health, particularly in Asia. The stamen of N. nucifera is an important part of this medicinal plant that is used in the form of dried and/or powdered stamens for herbal tea as well as the main ingredient of some traditional remedies. However, there is another aquatic herb called “Bau Sai” or Nymphaea lotus L. that is distributed in similar locations. Living plants of these two aquatic species may be classified according to their morphology, but the dried and powdered stamens of these two medicinal species are difficult to distinguish. The major reason of adulteration is the higher price of Bau Luang stamen. As a result, various methods of authentication, such as pollen micromorphology evaluation using scanning electron microscopy (SEM) analysis, bioinformatics analysis of two nuclear and plastic DNA markers, phytochemical stamen profiling, and Fourier transform infrared (FTIR) analysis of stamen plant material authentication from Bau Luang and Bau Sai, have been used in this present research in order to avoid some adulteration and/or misuse between the dried stamens of Bau Luang and Bau Sai. These results showed that the micro-morphology of pollen (size of pollen grain, number of apertures, and surface ornamentation) from the SEM analysis, some phytochemical compounds and the FTIR sporopollenin-to-protein ratio signal analysis are potential tools for authentication and identification of these two medicinal plants from their dried-stamen materials. This model of investigation may also be used to distinguish dried plant material from other problematic plant groups. Full article

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19 pages, 1198 KiB

Open AccessEditor’s ChoiceReview

Advances in Plant Regeneration: Shake, Rattle and Roll

by Sergio Ibáñez, Elena Carneros, Pilar S. Testillano and José Manuel Pérez-Pérez

Plants 2020, 9(7), 897; https://doi.org/10.3390/plants9070897 - 16 Jul 2020

Cited by 31 | Viewed by 8212

Abstract

Some plant cells are able to rebuild new organs after tissue damage or in response to definite stress treatments and/or exogenous hormone applications. Whole plants can develop through de novo organogenesis or somatic embryogenesis. Recent findings have enlarged our understanding of the molecular [...] Read more.

Some plant cells are able to rebuild new organs after tissue damage or in response to definite stress treatments and/or exogenous hormone applications. Whole plants can develop through de novo organogenesis or somatic embryogenesis. Recent findings have enlarged our understanding of the molecular and cellular mechanisms required for tissue reprogramming during plant regeneration. Genetic analyses also suggest the key role of epigenetic regulation during de novo plant organogenesis. A deeper understanding of plant regeneration might help us to enhance tissue culture optimization, with multiple applications in plant micropropagation and green biotechnology. In this review, we will provide additional insights into the physiological and molecular framework of plant regeneration, including both direct and indirect de novo organ formation and somatic embryogenesis, and we will discuss the key role of intrinsic and extrinsic constraints for cell reprogramming during plant regeneration. Full article

(This article belongs to the Special Issue Advances in Plant Regeneration)

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14 pages, 1007 KiB

Open AccessEditor’s ChoiceReview

Distinct Responses to Light in Plants

by Rita Teresa Teixeira

Plants 2020, 9(7), 894; https://doi.org/10.3390/plants9070894 - 15 Jul 2020

Cited by 29 | Viewed by 7541

Abstract

The development of almost every living organism is, to some extent, regulated by light. When discussing light regulation on biological systems, one is referring to the sun that has long been positioned in the center of the solar system. Through light regulation, all [...] Read more.

The development of almost every living organism is, to some extent, regulated by light. When discussing light regulation on biological systems, one is referring to the sun that has long been positioned in the center of the solar system. Through light regulation, all life forms have evolved around the presence of the sun. As soon our planet started to develop an atmospheric shield against most of the detrimental solar UV rays, life invaded land, and in the presence of water, it thrived. Especially for plants, light (solar radiation) is the source of energy that controls a high number of developmental aspects of growth, a process called photomorphogenesis. Once hypocotyls reach soil′s surface, its elongation deaccelerates, and the photosynthetic apparatus is established for an autotrophic growth due to the presence of light. Plants can sense light intensities, light quality, light direction, and light duration through photoreceptors that accurately detect alterations in the spectral composition (UV-B to far-red) and are located throughout the plant. The most well-known mechanism promoted by light occurring on plants is photosynthesis, which converts light energy into carbohydrates. Plants also use light to signal the beginning/end of key developmental processes such as the transition to flowering and dormancy. These two processes are particularly important for plant´s yield, since transition to flowering reduces the duration of the vegetative stage, and for plants growing under temperate or boreal climates, dormancy leads to a complete growth arrest. Understanding how light affects these processes enables plant breeders to produce crops which are able to retard the transition to flowering and avoid dormancy, increasing the yield of the plant. Full article

(This article belongs to the Special Issue Light Signaling in Plants)

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17 pages, 2901 KiB

Open AccessEditor’s ChoiceArticle

Feeding Behavior and Virus-transmission Ability of Insect Vectors Exposed to Systemic Insecticides

by Elisa Garzo, Aránzazu Moreno, María Plaza and Alberto Fereres

Plants 2020, 9(7), 895; https://doi.org/10.3390/plants9070895 - 15 Jul 2020

Cited by 42 | Viewed by 7631

Abstract

The majority of plant viruses depend on Hemipteran vectors for their survival and spread. Effective management of these insect vectors is crucial to minimize the spread of vector-borne diseases, and to reduce crop damage. The aim of the present study was to evaluate [...] Read more.

The majority of plant viruses depend on Hemipteran vectors for their survival and spread. Effective management of these insect vectors is crucial to minimize the spread of vector-borne diseases, and to reduce crop damage. The aim of the present study was to evaluate the effect of various systemic insecticides on the feeding behavior of Bemisia tabaci and Myzus persicae, as well as their ability to interfere with the transmission of circulative viruses. The obtained results indicated that some systemic insecticides have antifeeding properties that disrupt virus transmission by their insect vectors. We found that some of the tested insecticides significantly reduced phloem contact and sap ingestion by aphids and whiteflies, activities that are closely linked to the transmission of phloem-limited viruses. These systemic insecticides may play an important role in reducing the primary and secondary spread of tomato yellow leaf curl virus (TYLCV) and turnip yellows virus (TuYV), transmitted by B. tabaci and M. persicae, respectively. Full article

(This article belongs to the Special Issue Insect-Plant-Microbe Interactions)

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73 pages, 1977 KiB

Open AccessEditor’s ChoiceReview

Phytochemistry, Chemotaxonomy, and Biological Activities of the Araucariaceae Family—A Review

by Claudio Frezza, Alessandro Venditti, Daniela De Vita, Chiara Toniolo, Marco Franceschin, Antonio Ventrone, Lamberto Tomassini, Sebastiano Foddai, Marcella Guiso, Marcello Nicoletti, Armandodoriano Bianco and Mauro Serafini

Plants 2020, 9(7), 888; https://doi.org/10.3390/plants9070888 - 14 Jul 2020

Cited by 30 | Viewed by 5514

Abstract

In this review article, the phytochemistry of the species belonging to the Araucariaceae family is explored. Among these, in particular, it is given a wide overview on the phytochemical profile of Wollemia genus, for the first time. In addition to this, the ethnopharmacology [...] Read more.

In this review article, the phytochemistry of the species belonging to the Araucariaceae family is explored. Among these, in particular, it is given a wide overview on the phytochemical profile of Wollemia genus, for the first time. In addition to this, the ethnopharmacology and the general biological activities associated to the Araucariaceae species are singularly described. Lastly, the chemotaxonomy at the genus and family levels is described and detailed. Full article

(This article belongs to the Section Phytochemistry)

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29 pages, 3132 KiB

Open AccessEditor’s ChoiceArticle

Separation and Paired Proteome Profiling of Plant Chloroplast and Cytoplasmic Ribosomes

by Alexandre Augusto Pereira Firmino, Michal Gorka, Alexander Graf, Aleksandra Skirycz, Federico Martinez-Seidel, Kerstin Zander, Joachim Kopka and Olga Beine-Golovchuk

Plants 2020, 9(7), 892; https://doi.org/10.3390/plants9070892 - 14 Jul 2020

Cited by 14 | Viewed by 5798

Abstract

Conventional preparation methods of plant ribosomes fail to resolve non-translating chloroplast or cytoplasmic ribosome subunits from translating fractions. We established preparation of these ribosome complexes from Arabidopsis thaliana leaf, root, and seed tissues by optimized sucrose density gradient centrifugation of protease protected plant [...] Read more.

Conventional preparation methods of plant ribosomes fail to resolve non-translating chloroplast or cytoplasmic ribosome subunits from translating fractions. We established preparation of these ribosome complexes from Arabidopsis thaliana leaf, root, and seed tissues by optimized sucrose density gradient centrifugation of protease protected plant extracts. The method co-purified non-translating 30S and 40S ribosome subunits separated non-translating 50S from 60S subunits, and resolved assembled monosomes from low oligomeric polysomes. Combining ribosome fractionation with microfluidic rRNA analysis and proteomics, we characterized the rRNA and ribosomal protein (RP) composition. The identity of cytoplasmic and chloroplast ribosome complexes and the presence of ribosome biogenesis factors in the 60S-80S sedimentation interval were verified. In vivo cross-linking of leaf tissue stabilized ribosome biogenesis complexes, but induced polysome run-off. Omitting cross-linking, the established paired fractionation and proteome analysis monitored relative abundances of plant chloroplast and cytoplasmic ribosome fractions and enabled analysis of RP composition and ribosome associated proteins including transiently associated biogenesis factors. Full article

(This article belongs to the Special Issue Plant Ribosome Biogenesis)

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13 pages, 2769 KiB

Open AccessEditor’s ChoiceArticle

Fungal Pathogens Affecting the Production and Quality of Medical Cannabis in Israel

by Shachar Jerushalmi, Marcel Maymon, Aviv Dombrovsky and Stanley Freeman

Plants 2020, 9(7), 882; https://doi.org/10.3390/plants9070882 - 13 Jul 2020

Cited by 34 | Viewed by 7580

Abstract

The use of and research on medical cannabis (MC) is becoming more common, yet there are still many challenges regarding plant diseases of this crop. For example, there is a lack of formal and professional knowledge regarding fungi that infect MC plants, and [...] Read more.

The use of and research on medical cannabis (MC) is becoming more common, yet there are still many challenges regarding plant diseases of this crop. For example, there is a lack of formal and professional knowledge regarding fungi that infect MC plants, and practical and effective methods for managing the casual agents of disease are limited. The purpose of this study was to identify foliar, stem, and soilborne pathogens affecting MC under commercial cultivation in Israel. The predominant major foliage pathogens were identified as Alternaria alternata and Botrytis cinerea, while the common stem and soilborne pathogens were identified as Fusarium oxysporum and F. solani. Other important fungi that were isolated from foliage were those producing various mycotoxins that can directly harm patients, such as Aspergillus spp. and Penicillium spp. The sampling and characterization of potential pathogenic fungi were conducted from infected MC plant parts that exhibited various disease symptoms. Koch postulates were conducted by inoculating healthy MC tissues and intact plants with fungi isolated from infected commercially cultivated symptomatic plants. In this study, we report on the major and most common plant pathogens of MC found in Israel, and determine the seasonal outbreak of each fungus. Full article

(This article belongs to the Special Issue The Challenge of Coping with Globally and Locally Emerging Fungal and Oomycetes Plant Pathogens)

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13 pages, 2215 KiB

Open AccessEditor’s ChoiceArticle

Some Accessions of Amazonian Wild Rice (Oryza glumaepatula) Constitutively Form a Barrier to Radial Oxygen Loss along Adventitious Roots under Aerated Conditions

by Masato Ejiri, Yuto Sawazaki and Katsuhiro Shiono

Plants 2020, 9(7), 880; https://doi.org/10.3390/plants9070880 - 13 Jul 2020

Cited by 20 | Viewed by 2813

Abstract

A barrier to radial oxygen loss (ROL), which reduces the loss of oxygen transported via the aerenchyma to the root tips, enables the roots of wetland plants to grow into anoxic/hypoxic waterlogged soil. However, little is known about its genetic regulation. Quantitative trait [...] Read more.

A barrier to radial oxygen loss (ROL), which reduces the loss of oxygen transported via the aerenchyma to the root tips, enables the roots of wetland plants to grow into anoxic/hypoxic waterlogged soil. However, little is known about its genetic regulation. Quantitative trait loci (QTLs) mapping can help to understand the factors that regulate barrier formation. Rice (Oryza sativa) inducibly forms an ROL barrier under stagnant conditions, while a few wetland plants constitutively form one under aerated conditions. Here, we evaluated the formation of a constitutive ROL barrier in a total of four accessions from two wild rice species. Three of the accessions were wetland accessions of O. glumaepatula, and the fourth was a non-wetland species of O. rufipogon. These species have an AA type genome, which allows them to be crossed with cultivated rice. The three O. glumaepatula accessions (W2165, W2149, and W1183) formed an ROL barrier under aerated conditions. The O. rufipogon accession (W1962) did not form a constitutive ROL barrier, but it formed an inducible ROL barrier under stagnant conditions. The three O. glumaepatula accessions should be useful for QTL mapping to understand how a constitutive ROL barrier forms. The constitutive barrier of W2165 was closely associated with suberization and resistance to penetration by an apoplastic tracer (periodic acid) at the exodermis but did not include lignin at the sclerenchyma. Full article

(This article belongs to the Special Issue Plant Responses to Hypoxia)

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14 pages, 1349 KiB

Open AccessEditor’s ChoiceArticle

Biodiversity of β-Carboline Profile of Banisteriopsis caapi and Ayahuasca, a Plant and a Brew with Neuropharmacological Potential

by Beatriz Werneck Lopes Santos, Regina Célia de Oliveira, Julia Sonsin-Oliveira, Christopher William Fagg, José Beethoven Figueiredo Barbosa and Eloisa Dutra Caldas

Plants 2020, 9(7), 870; https://doi.org/10.3390/plants9070870 - 9 Jul 2020

Cited by 18 | Viewed by 9178

Abstract

Ayahuasca is a psychoactive infusion with a large pharmacological application normally prepared with Banisteriopsis caapi, which contains the monoamine oxidase inhibitors β-carbolines, and Psichotria virids, which contains the serotonin receptor agonist N,N dimethyltryptamine (DMT). The objectives of this study were to [...] Read more.

Ayahuasca is a psychoactive infusion with a large pharmacological application normally prepared with Banisteriopsis caapi, which contains the monoamine oxidase inhibitors β-carbolines, and Psichotria virids, which contains the serotonin receptor agonist N,N dimethyltryptamine (DMT). The objectives of this study were to investigate the chemical profile of B. caapi and of ayahuasca collected in various Brazilian regions. In total, 176 plant lianas, of which 159 B. caapi and 33 ayahuasca samples were analyzed. Dried liana samples were powdered, extracted with methanol, diluted, and analyzed by LC-MS/MS. Ayahuasca samples were diluted and analyzed. Mean concentrations in B. caapi were 4.79 mg/g harmine, 0.451 mg/g harmaline, and 2.18 mg/g tetrahydroharmine (THH), with a high variability among the samples (RSD from 78.9 to 170%). Native B. caapi samples showed significantly higher harmine concentrations than cultivated ones, and samples from the Federal District/Goiás had higher THH content than those collected in the State of Acre. The other Malpighiaceae samples did not contain β-carbolines, except for one D. pubipetala sample. Concentrations in ayahuasca samples ranged from 0.109 to 7.11 mg/mL harmine, 0.012 to 0.945 mg/mL harmaline, 0.09 to 3.05 mg/mL THH, and 0.10 to 3.12 mg/mL DMT. The analysis of paired ayahuasca/B. caapi confirmed that harmine is reduced to harmaline and to THH during the brew preparation. This is the largest study conducted with Malpighiaceae samples and showed a large variability in the main β-carbolines present in B. caapi. This biodiversity is a challenge for standardization of the material used in ethnopharmacological studies of B. caapi and ayahuasca. Full article

(This article belongs to the Collection Bioactive Compounds in Plants)

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19 pages, 989 KiB

Open AccessEditor’s ChoiceReview

Plant Molecular Farming: A Viable Platform for Recombinant Biopharmaceutical Production

by Balamurugan Shanmugaraj, Christine Joy I. Bulaon and Waranyoo Phoolcharoen

Plants 2020, 9(7), 842; https://doi.org/10.3390/plants9070842 - 4 Jul 2020

Cited by 139 | Viewed by 21719

Abstract

The demand for recombinant proteins in terms of quality, quantity, and diversity is increasing steadily, which is attracting global attention for the development of new recombinant protein production technologies and the engineering of conventional established expression systems based on bacteria or mammalian cell [...] Read more.

The demand for recombinant proteins in terms of quality, quantity, and diversity is increasing steadily, which is attracting global attention for the development of new recombinant protein production technologies and the engineering of conventional established expression systems based on bacteria or mammalian cell cultures. Since the advancements of plant genetic engineering in the 1980s, plants have been used for the production of economically valuable, biologically active non-native proteins or biopharmaceuticals, the concept termed as plant molecular farming (PMF). PMF is considered as a cost-effective technology that has grown and advanced tremendously over the past two decades. The development and improvement of the transient expression system has significantly reduced the protein production timeline and greatly improved the protein yield in plants. The major factors that drive the plant-based platform towards potential competitors for the conventional expression system are cost-effectiveness, scalability, flexibility, versatility, and robustness of the system. Many biopharmaceuticals including recombinant vaccine antigens, monoclonal antibodies, and other commercially viable proteins are produced in plants, some of which are in the pre-clinical and clinical pipeline. In this review, we consider the importance of a plant- based production system for recombinant protein production, and its potential to produce biopharmaceuticals is discussed. Full article

(This article belongs to the Special Issue Plant Molecular Farming)

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10 pages, 1077 KiB

Open AccessEditor’s ChoiceCommunication

Two New Putative Plant Viruses from Wood Metagenomics Analysis of an Esca Diseased Vineyard

by Nadia Bertazzon, Walter Chitarra, Elisa Angelini and Luca Nerva

Plants 2020, 9(7), 835; https://doi.org/10.3390/plants9070835 - 3 Jul 2020

Cited by 14 | Viewed by 3391

Abstract

The concept of plant as a holobiont is now spreading among the scientific community and the importance to study plant-associated microorganisms is becoming more and more necessary. Along with bacteria and fungi, also viruses can play important roles during the holobiont-environment interactions. In [...] Read more.

The concept of plant as a holobiont is now spreading among the scientific community and the importance to study plant-associated microorganisms is becoming more and more necessary. Along with bacteria and fungi, also viruses can play important roles during the holobiont-environment interactions. In grapevine, viruses are studied mainly as pathological agents, and many species (more than 80) are known to be able to replicate inside its tissues. In this study two new viral species associated with grape wood tissues are presented, one belongs to the Potyviridae family and one to the Bunyavirales order. Due to the ability of potyviruses to enhance heterologous virus replication, it will be important to assess the presence of such a virus in the grapevine population to understand its ecological role. Furthermore, the association of the cogu-like virus with esca symptomatic samples opens new questions and the necessity of a more detailed characterization of this virus. Full article

(This article belongs to the Special Issue Diagnosis and Control of Plant Viral Diseases)

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15 pages, 1654 KiB

Open AccessEditor’s ChoiceArticle

The Essential Oil Composition and Antimicrobial Activity of Liquidambar formosana Oleoresin

by Anjanette DeCarlo, Tao Zeng, Noura S. Dosoky, Prabodh Satyal and William N. Setzer

Plants 2020, 9(7), 822; https://doi.org/10.3390/plants9070822 - 30 Jun 2020

Cited by 25 | Viewed by 7787

Abstract

The oleoresin essential oils of Liquidambar formosana have potential therapeutic benefits. However, current research on L. formosana oleoresin essential oil is still in its early stages, and its chemotypic characterization is undefined. For better leveraging of plant resources and application of the essential [...] Read more.

The oleoresin essential oils of Liquidambar formosana have potential therapeutic benefits. However, current research on L. formosana oleoresin essential oil is still in its early stages, and its chemotypic characterization is undefined. For better leveraging of plant resources and application of the essential oil, we collected 25 L. formosana oleoresin essential oil samples of individual trees from different geographical areas of Southern China. The essential oils were obtained by hydrodistillation and analyzed by gas chromatography–mass spectrometry (GC–MS) and gas chromatography–flame ionization detection (GC–FID). The major components of the essential oils were (E)-caryophyllene (3.3%-64.4%), α-pinene (0.6%-34.5%), β-pinene (0.6%-26.0%), camphene (0.3%-17.3%), and limonene (0.2%-7.9%). A chiral GC–MS analysis was carried out on the essential oil samples and (–)-α-Pinene, (–)-β-pinene, (–)-camphene, and (–)-limonene were the dominant enantiomers in L. formosana essential oil. The chemical categories of L. formosana oleoresin essential oils were clarified by agglomerative hierarchical cluster analysis (AHC) and principal component analysis (PCA). The multivariate analyses demonstrated that a total of four chemical groups can be delineated for L. formosana. The L. formosana essential oils were screened for antimicrobial activity against a panel of potentially pathogenic bacteria and fungi and showed promising antimicrobial activities with minimum inhibitory concentration (MIC) ≤ 625 μg/mL. These results highlight the economic value of L. formosana oleoresin essential oil, the importance of L. formosana sustainability, and the potential therapeutic benefits of its oleoresin essential oils. Full article

(This article belongs to the Section Phytochemistry)

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27 pages, 2490 KiB

Open AccessEditor’s ChoiceReview

Genebank Phenomics: A Strategic Approach to Enhance Value and Utilization of Crop Germplasm

by Giao N. Nguyen and Sally L. Norton

Plants 2020, 9(7), 817; https://doi.org/10.3390/plants9070817 - 29 Jun 2020

Cited by 36 | Viewed by 7900

Abstract

Genetically diverse plant germplasm stored in ex-situ genebanks are excellent resources for breeding new high yielding and sustainable crop varieties to ensure future food security. Novel alleles have been discovered through routine genebank activities such as seed regeneration and characterization, with subsequent utilization [...] Read more.

Genetically diverse plant germplasm stored in ex-situ genebanks are excellent resources for breeding new high yielding and sustainable crop varieties to ensure future food security. Novel alleles have been discovered through routine genebank activities such as seed regeneration and characterization, with subsequent utilization providing significant genetic gains and improvements for the selection of favorable traits, including yield, biotic, and abiotic resistance. Although some genebanks have implemented cost-effective genotyping technologies through advances in DNA technology, the adoption of modern phenotyping is lagging. The introduction of advanced phenotyping technologies in recent decades has provided genebank scientists with time and cost-effective screening tools to obtain valuable phenotypic data for more traits on large germplasm collections during routine activities. The utilization of these phenotyping tools, coupled with high-throughput genotyping, will accelerate the use of genetic resources and fast-track the development of more resilient food crops for the future. In this review, we highlight current digital phenotyping methods that can capture traits during annual seed regeneration to enrich genebank phenotypic datasets. Next, we describe strategies for the collection and use of phenotypic data of specific traits for downstream research using high-throughput phenotyping technology. Finally, we examine the challenges and future perspectives of genebank phenomics. Full article

(This article belongs to the Special Issue Plant Biodiversity and Genetic Resources)

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12 pages, 1859 KiB

Open AccessEditor’s ChoiceArticle

Geranium and Lemon Essential Oils and Their Active Compounds Downregulate Angiotensin-Converting Enzyme 2 (ACE2), a SARS-CoV-2 Spike Receptor-Binding Domain, in Epithelial Cells

by K. J. Senthil Kumar, M. Gokila Vani, Chung-Shuan Wang, Chia-Chi Chen, Yu-Chien Chen, Li-Ping Lu, Ching-Hsiang Huang, Chien-Sing Lai and Sheng-Yang Wang

Plants 2020, 9(6), 770; https://doi.org/10.3390/plants9060770 - 19 Jun 2020

Cited by 102 | Viewed by 59898

Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), also known as coronavirus disease-2019 (COVID-19), is a pandemic disease that has been declared as modern history’s gravest health emergency worldwide. Until now, no precise treatment modality has been developed. The angiotensin-converting enzyme 2 (ACE2) receptor, [...] Read more.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), also known as coronavirus disease-2019 (COVID-19), is a pandemic disease that has been declared as modern history’s gravest health emergency worldwide. Until now, no precise treatment modality has been developed. The angiotensin-converting enzyme 2 (ACE2) receptor, a host cell receptor, has been found to play a crucial role in virus cell entry; therefore, ACE2 blockers can be a potential target for anti-viral intervention. In this study, we evaluated the ACE2 inhibitory effects of 10 essential oils. Among them, geranium and lemon oils displayed significant ACE2 inhibitory effects in epithelial cells. In addition, immunoblotting and qPCR analysis also confirmed that geranium and lemon oils possess potent ACE2 inhibitory effects. Furthermore, the gas chromatography-mass spectrometry (GC–MS) analysis displayed 22 compounds in geranium oil and 9 compounds in lemon oil. Citronellol, geraniol, and neryl acetate were the major compounds of geranium oil and limonene that represented major compound of lemon oil. Next, we found that treatment with citronellol and limonene significantly downregulated ACE2 expression in epithelial cells. The results suggest that geranium and lemon essential oils and their derivative compounds are valuable natural anti-viral agents that may contribute to the prevention of the invasion of SARS-CoV-2/COVID-19 into the human body. Full article

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17 pages, 4525 KiB

Open AccessEditor’s ChoiceArticle

Cucumber Fruit Size and Shape Variations Explored from the Aspects of Morphology, Histology, and Endogenous Hormones

by Xiaoxiao Liu, Yupeng Pan, Ce Liu, Yuanyuan Ding, Xiao Wang, Zhihui Cheng and Huanwen Meng

Plants 2020, 9(6), 772; https://doi.org/10.3390/plants9060772 - 19 Jun 2020

Cited by 34 | Viewed by 14101

Abstract

Fruit size and shape are important qualities and yield traits in cucumber (Cucumis sativus L.), but the factors that influence fruit size and shape remain to be explored. In this study, we investigated the dynamic changes of fruit size and shape from [...] Read more.

Fruit size and shape are important qualities and yield traits in cucumber (Cucumis sativus L.), but the factors that influence fruit size and shape remain to be explored. In this study, we investigated the dynamic changes of fruit size and shape from the aspects of morphology, cellular levels and endogenous hormones for nine typical cucumber inbred lines. The results show that fruit length had a strong positive correlation to the cell number in the longitudinal section of fruit throughout the four stages of 0, 6, 12, and 30 DAA (days after anthesis). However, the significant negative correlations were found between fruit length and the fruit cell size at 12 and 30 DAA. Furthermore, fruit diameter was positively correlated to the cell number in the cross section at all the investigated fruit growth stages. The indole-3-acetic acid (IAA) content showed significant positive correlations to the fruit length at all fruit growth stages of −6, −3, 0, 3, 6, 9 and 12 DAA, but IAA content and fruit diameter showed significant negative correlations for all the stages except for at −6 DAA. The trans-zeatin riboside (tZR), zeatin (ZT), gibberellic acid (GA₃) and jasmonic acid (JA) content had a positive or negative correlation with fruit length or diameter only at certain stages. Neither fruit length nor diameter had significant correlations to abscisic acid (ABA) content. These results indicate that variations in fruit size and shape of different cucumber inbred lines mainly result from the differences in fruit cell number and endogenous IAA content. The present work is the first to propose cucumber fruit size and shape changes from the combined aspects of morphology, cellular levels, and endogenous hormones. Full article

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15 pages, 1041 KiB

Open AccessEditor’s ChoiceArticle

Application of Trichoderma harzianum, 6-Pentyl-α-pyrone and Plant Biopolymer Formulations Modulate Plant Metabolism and Fruit Quality of Plum Tomatoes

by Petronia Carillo, Sheridan L. Woo, Ernesto Comite, Christophe El-Nakhel, Youssef Rouphael, Giovanna Marta Fusco, Assunta Borzacchiello, Stefania Lanzuise and Francesco Vinale

Plants 2020, 9(6), 771; https://doi.org/10.3390/plants9060771 - 19 Jun 2020

Cited by 59 | Viewed by 6278

Abstract

Many Trichoderma are successfully used to improve agriculture productivity due to their capacity for biocontrol and to stimulate plant growth and tolerance to abiotic stress. This research elucidates the effect of applications with Trichoderma harzianum strain T22 (T22), or biopolymer (BP) alone or [...] Read more.

Many Trichoderma are successfully used to improve agriculture productivity due to their capacity for biocontrol and to stimulate plant growth and tolerance to abiotic stress. This research elucidates the effect of applications with Trichoderma harzianum strain T22 (T22), or biopolymer (BP) alone or in combination (BP + T22 or BP + 6-pentyl-α-pyrone (6PP); a Trichoderma secondary metabolite) on the crop performance, nutritional and functional quality of greenhouse tomato (Solanum lycopersicum L. cultivar Pixel). T22 elicited significant increases in total yield (+40.1%) compared to untreated tomato. The content of lycopene, an important antioxidant compound in tomatoes, significantly increased upon treatment with T22 (+ 49%), BP + T22 (+ 40%) and BP + 6PP (+ 52%) compared to the control. T22 treatments significantly increased the content of asparagine (+37%), GABA (+87%) and MEA (+102%) over the control; whereas BP alone strongly increased GABA (+105%) and MEA (+85%). The synthesis of these compounds implies that tomato plants are able to reuse the photorespiratory amino acids and ammonium for producing useful metabolites and reduce the pressure of photorespiration on plant metabolism, thus optimizing photosynthesis and growth. Finally, these metabolites exert many beneficial effects for human health, thus enhancing the premium quality of plum tomatoes. Full article

(This article belongs to the Special Issue 2019 Feature Papers by Plants’ Editorial Board Members)

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14 pages, 1912 KiB

Open AccessEditor’s ChoiceReview

The Many Facets of Hypoxia in Plants

by Elena Loreti and Pierdomenico Perata

Plants 2020, 9(6), 745; https://doi.org/10.3390/plants9060745 - 12 Jun 2020

Cited by 88 | Viewed by 13975

Abstract

Plants are aerobic organisms that require oxygen for their respiration. Hypoxia arises due to the insufficient availability of oxygen, and is sensed by plants, which adapt their growth and metabolism accordingly. Plant hypoxia can occur as a result of excessive rain and soil [...] Read more.

Plants are aerobic organisms that require oxygen for their respiration. Hypoxia arises due to the insufficient availability of oxygen, and is sensed by plants, which adapt their growth and metabolism accordingly. Plant hypoxia can occur as a result of excessive rain and soil waterlogging, thus constraining plant growth. Increasing research on hypoxia has led to the discovery of the mechanisms that enable rice to be productive even when partly submerged. The identification of Ethylene Response Factors (ERFs) as the transcription factors that enable rice to survive submergence has paved the way to the discovery of oxygen sensing in plants. This, in turn has extended the study of hypoxia to plant development and plant–microbe interaction. In this review, we highlight the many facets of plant hypoxia, encompassing stress physiology, developmental biology and plant pathology. Full article

(This article belongs to the Special Issue Plant Responses to Hypoxia)

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17 pages, 337 KiB

Open AccessEditor’s ChoiceReview

The Role of Microbial Inoculants on Plant Protection, Growth Stimulation, and Crop Productivity of the Olive Tree (Olea europea L.)

by Georgios Bizos, Efimia M. Papatheodorou, Theocharis Chatzistathis, Nikoletta Ntalli, Vassilis G. Aschonitis and Nikolaos Monokrousos

Plants 2020, 9(6), 743; https://doi.org/10.3390/plants9060743 - 12 Jun 2020

Cited by 49 | Viewed by 6902

Abstract

The olive tree (Olea europaea L.) is an emblematic, long-living fruit tree species of profound economic and environmental importance. This study is a literature review of articles published during the last 10 years about the role of beneficial microbes [Arbuscular Mycorrhizal Fungi [...] Read more.

The olive tree (Olea europaea L.) is an emblematic, long-living fruit tree species of profound economic and environmental importance. This study is a literature review of articles published during the last 10 years about the role of beneficial microbes [Arbuscular Mycorrhizal Fungi (AMF), Plant Growth Promoting Rhizobacteria (PGPR), Plant Growth Promoting Fungi (PGPF), and Endophytes] on olive tree plant growth and productivity, pathogen control, and alleviation from abiotic stress. The majority of the studies examined the AMF effect using mostly Rhizophagus irregularis and Glomus mosseae species. These AMF species stimulate the root growth improving the resistance of olive plants to environmental and transplantation stresses. Among the PGPR, the nitrogen-fixing bacteria Azospirillum sp. and potassium- and phosphorous-solubilizing Bacillus sp. species were studied extensively. These PGPR species were combined with proper cultural practices and improved considerably olive plant’s growth. The endophytic bacterial species Pseudomonas fluorescens and Bacillus sp., as well as the fungal species Trichoderma sp. were identified as the most effective biocontrol agents against olive tree diseases (e.g., Verticillium wilt, root rot, and anthracnose). Full article

(This article belongs to the Special Issue Biostimulants in Plants Science)

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31 pages, 3405 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Verticillium Wilt of Olive and Its Control: What Did We Learn during the Last Decade?

by Nuria Montes-Osuna and Jesús Mercado-Blanco

Plants 2020, 9(6), 735; https://doi.org/10.3390/plants9060735 - 11 Jun 2020

Cited by 64 | Viewed by 9901

Abstract

Verticillium (Verticillium dahliae Kleb.) wilt is one of the most devastating diseases affecting olive (Olea europaea L. subsp. europaea var. europaea) cultivation. Its effective control strongly relies on integrated management strategies. Olive cultivation systems are experiencing important changes (e.g., high-density [...] Read more.

Verticillium (Verticillium dahliae Kleb.) wilt is one of the most devastating diseases affecting olive (Olea europaea L. subsp. europaea var. europaea) cultivation. Its effective control strongly relies on integrated management strategies. Olive cultivation systems are experiencing important changes (e.g., high-density orchards, etc.) aiming at improving productivity. The impact of these changes on soil biology and the incidence/severity of olive pests and diseases has not yet been sufficiently evaluated. A comprehensive understanding of the biology of the pathogen and its populations, the epidemiological factors contributing to exacerbating the disease, the underlying mechanisms of tolerance/resistance, and the involvement of the olive-associated microbiota in the tree’s health is needed. This knowledge will be instrumental to developing more effective control measures to confront the disease in regions where the pathogen is present, or to exclude it from V. dahliae-free areas. This review compiles the most recent advances achieved to understand the olive–V. dahliae interaction as well as measures to control the disease. Aspects such as the molecular basis of the host–pathogen interaction, the identification of new biocontrol agents, the implementation of “-omics” approaches to unravel the basis of disease tolerance, and the utilization of remote sensing technology for the early detection of pathogen attacks are highlighted. Full article

(This article belongs to the Special Issue Management of Verticillium Wilt Disease)

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9 pages, 1022 KiB

Open AccessEditor’s ChoiceArticle

Composition and Antioxidant Activities of Volatile Organic Compounds in Radiation-Bred Coreopsis Cultivars

by Bo-Ram Kim, Hyun Mi Kim, Chang Hyun Jin, Si-Yong Kang, Jin-Baek Kim, Yeo Gyeong Jeon, Kong Young Park, Ik-Soo Lee and Ah-Reum Han

Plants 2020, 9(6), 717; https://doi.org/10.3390/plants9060717 - 4 Jun 2020

Cited by 49 | Viewed by 3325

Abstract

Coreopsis is a flowering plant belonging to the Asteraceae family. It is an ornamental plant native to the Americas, Asia and Oceania and its flower is used as a raw material for tea and food manufacture in China. In this study, new cultivars [...] Read more.

Coreopsis is a flowering plant belonging to the Asteraceae family. It is an ornamental plant native to the Americas, Asia and Oceania and its flower is used as a raw material for tea and food manufacture in China. In this study, new cultivars of C. rosea (“golden ring”) were developed via radiation-induced mutation of the original cultivar, “pumpkin pie”. The chemical composition and antioxidant activities of flowers belonging to three different Coreopsis cultivars were evaluated: “golden ring”, “pumpkin pie” and “snow chrysanthemum” (coreopsis tea; C. tinctoria). The volatile compounds were characterized via gas chromatography-mass spectrometry (GC-MS) and 50–59 oils representing 95.3–96.8% of the total volatile compounds in these flower materials were identified. ”Golden ring” contained a high amount of fatty acids (38.13%), while “pumpkin pie” and “snow chrysanthemum” teas were rich in aliphatic amides (43.01%) and esters (67.22%), respectively. The antioxidant activities of the volatile oils of these cultivars were evaluated using 1,1-diphenyl-2-picrylhydraxyl (DPPH) and 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging assays. The volatile extract of “golden ring” showed higher antioxidant activities compared with the extracts of the other cultivars. Therefore, “golden ring” can be used for further development as a raw material for tea manufacture or as a dietary supplement. Full article

(This article belongs to the Special Issue Plant Mutation Breeding)

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20 pages, 891 KiB

Open AccessEditor’s ChoiceReview

Cellular, Molecular, and Physiological Aspects of In Vitro Plant Regeneration

by Siamak Shirani Bidabadi and S. Mohan Jain

Plants 2020, 9(6), 702; https://doi.org/10.3390/plants9060702 - 1 Jun 2020

Cited by 125 | Viewed by 17817

Abstract

Plants generally have the highest regenerative ability because they show a high degree of developmental plasticity. Although the basic principles of plant regeneration date back many years, understanding the cellular, molecular, and physiological mechanisms based on these principles is currently in progress. In [...] Read more.

Plants generally have the highest regenerative ability because they show a high degree of developmental plasticity. Although the basic principles of plant regeneration date back many years, understanding the cellular, molecular, and physiological mechanisms based on these principles is currently in progress. In addition to the significant effects of some factors such as medium components, phytohormones, explant type, and light on the regeneration ability of an explant, recent reports evidence the involvement of molecular signals in organogenesis and embryogenesis responses to explant wounding, induced plant cell death, and phytohormones interaction. However, some cellular behaviors such as the occurrence of somaclonal variations and abnormalities during the in vitro plant regeneration process may be associated with adverse effects on the efficacy of plant regeneration. A review of past studies suggests that, in some cases, regeneration in plants involves the reprogramming of distinct somatic cells, while in others, it is induced by the activation of relatively undifferentiated cells in somatic tissues. However, this review covers the most important factors involved in the process of plant regeneration and discusses the mechanisms by which plants monitor this process. Full article

(This article belongs to the Special Issue Advances in Plant Regeneration)

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41 pages, 1624 KiB

Open AccessEditor’s ChoiceReview

An Updated Overview on the Regulation of Seed Germination

by Gerardo Carrera-Castaño, Julián Calleja-Cabrera, Mónica Pernas, Luis Gómez and Luis Oñate-Sánchez

Plants 2020, 9(6), 703; https://doi.org/10.3390/plants9060703 - 1 Jun 2020

Cited by 111 | Viewed by 14256

Abstract

The ability of a seed to germinate and establish a plant at the right time of year is of vital importance from an ecological and economical point of view. Due to the fragility of these early growth stages, their swiftness and robustness will [...] Read more.

The ability of a seed to germinate and establish a plant at the right time of year is of vital importance from an ecological and economical point of view. Due to the fragility of these early growth stages, their swiftness and robustness will impact later developmental stages and crop yield. These traits are modulated by a continuous interaction between the genetic makeup of the plant and the environment from seed production to germination stages. In this review, we have summarized the established knowledge on the control of seed germination from a molecular and a genetic perspective. This serves as a “backbone” to integrate the latest developments in the field. These include the link of germination to events occurring in the mother plant influenced by the environment, the impact of changes in the chromatin landscape, the discovery of new players and new insights related to well-known master regulators. Finally, results from recent studies on hormone transport, signaling, and biophysical and mechanical tissue properties are underscoring the relevance of tissue-specific regulation and the interplay of signals in this crucial developmental process. Full article

(This article belongs to the Special Issue Genetics of Seed Germination and Growth)

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17 pages, 747 KiB

Open AccessEditor’s ChoiceReview

Auxin: Hormonal Signal Required for Seed Development and Dormancy

by Angel J. Matilla

Plants 2020, 9(6), 705; https://doi.org/10.3390/plants9060705 - 1 Jun 2020

Cited by 50 | Viewed by 6891

Abstract

The production of viable seeds is a key event in the life cycle of higher plants. Historically, abscisic acid (ABA) and gibberellin (GAs) were considered the main hormones that regulate seed formation. However, auxin has recently emerged as an essential player that modulates, [...] Read more.

The production of viable seeds is a key event in the life cycle of higher plants. Historically, abscisic acid (ABA) and gibberellin (GAs) were considered the main hormones that regulate seed formation. However, auxin has recently emerged as an essential player that modulates, in conjunction with ABA, different cellular processes involved in seed development as well as the induction, regulation and maintenance of primary dormancy (PD). This review examines and discusses the key role of auxin as a signaling molecule that coordinates seed life. The cellular machinery involved in the synthesis and transport of auxin, as well as their cellular and tissue compartmentalization, is crucial for the development of the endosperm and seed-coat. Thus, auxin is an essential compound involved in integuments development, and its transport from endosperm is regulated by AGAMOUS-LIKE62 (AGL62) whose transcript is specifically expressed in the endosperm. In addition, recent biochemical and genetic evidence supports the involvement of auxins in PD. In this process, the participation of the transcriptional regulator ABA INSENSITIVE3 (ABI3) is critical, revealing a cross-talk between auxin and ABA signaling. Future experimental aimed at advancing knowledge of the role of auxins in seed development and PD are also discussed. Full article

(This article belongs to the Special Issue Seed Dormancy: Molecular Control of Its Induction and Alleviation)

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31 pages, 3169 KiB

Open AccessEditor’s ChoiceArticle

Bioactive Compounds and Aroma Profile of Some Lamiaceae Edible Flowers

by Ilaria Marchioni, Basma Najar, Barbara Ruffoni, Andrea Copetta, Luisa Pistelli and Laura Pistelli

Plants 2020, 9(6), 691; https://doi.org/10.3390/plants9060691 - 28 May 2020

Cited by 48 | Viewed by 5625

Abstract

Edible flowers are consumed for their appearance, colours, nutritional and healthy properties, but the use is limited by the actual number of the species. Seven edible flowers of the Lamiaceae family (Ocimeae and Mentheae tribes) were investigated: Monarda didyma ‘Fireball’, Nepeta × faassenii [...] Read more.

Edible flowers are consumed for their appearance, colours, nutritional and healthy properties, but the use is limited by the actual number of the species. Seven edible flowers of the Lamiaceae family (Ocimeae and Mentheae tribes) were investigated: Monarda didyma ‘Fireball’, Nepeta × faassenii ‘Six Hills Giant’, Ocimum basilicum ‘Blue Spice’, O. basilicum ‘Cinnamon’, Ocimum × citriodorum, Salvia discolor, and Salvia microphylla ‘Hot Lips’. Total soluble sugars, proteins, polyphenols, carotenoids, ascorbic acid and antioxidant activity were detected. The species of the Mentheae tribe contained higher sugar content than Ocimeae flowers, the opposite with regard to protein content. Ocimeae tribe flowers showed high polyphenols and carotenoids content. The Ocimeae tribe together with two specie of the Mentheae tribe showed an aroma profile dominated by sesquiterpene hydrocarbons (58.0% in S. discolor to 77.9% in Ocimum × citriodorum). Oxygenated monoterpenes prevailed in Nepeta and Monarda, also present in the essential oil of this latter species (84.5%). By contrast, Nepeta and S. discolor evidenced non-terpenes as the principal class (41.2% and 77.5%, respectively), while the oxygenated sesquiterpene was the main one in S. microphylla. The two varieties of Ocimum spp. showed oxygenated monoterpenes as the main class of volatiles. Full article

(This article belongs to the Special Issue Bioactive Compounds in Plants)

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14 pages, 1273 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Reactive Oxygen Species (ROS) and Nucleic Acid Modifications during Seed Dormancy

by Kai Katsuya-Gaviria, Elena Caro, Néstor Carrillo-Barral and Raquel Iglesias-Fernández

Plants 2020, 9(6), 679; https://doi.org/10.3390/plants9060679 - 27 May 2020

Cited by 36 | Viewed by 6394

Abstract

The seed is the propagule of higher plants and allows its dissemination and the survival of the species. Seed dormancy prevents premature germination under favourable conditions. Dormant seeds are only able to germinate in a narrow range of conditions. During after-ripening (AR), a [...] Read more.

The seed is the propagule of higher plants and allows its dissemination and the survival of the species. Seed dormancy prevents premature germination under favourable conditions. Dormant seeds are only able to germinate in a narrow range of conditions. During after-ripening (AR), a mechanism of dormancy release, seeds gradually lose dormancy through a period of dry storage. This review is mainly focused on how chemical modifications of mRNA and genomic DNA, such as oxidation and methylation, affect gene expression during late stages of seed development, especially during dormancy. The oxidation of specific nucleotides produced by reactive oxygen species (ROS) alters the stability of the seed stored mRNAs, being finally degraded or translated into non-functional proteins. DNA methylation is a well-known epigenetic mechanism of controlling gene expression. In Arabidopsis thaliana, while there is a global increase in CHH-context methylation through embryogenesis, global DNA methylation levels remain stable during seed dormancy, decreasing when germination occurs. The biological significance of nucleic acid oxidation and methylation upon seed development is discussed. Full article

(This article belongs to the Special Issue Seed Dormancy: Molecular Control of Its Induction and Alleviation)

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17 pages, 304 KiB

Open AccessEditor’s ChoiceReview

Plant Viruses Infecting Solanaceae Family Members in the Cultivated and Wild Environments: A Review

by Richard Hančinský, Daniel Mihálik, Michaela Mrkvová, Thierry Candresse and Miroslav Glasa

Plants 2020, 9(5), 667; https://doi.org/10.3390/plants9050667 - 25 May 2020

Cited by 50 | Viewed by 8617

Abstract

Plant viruses infecting crop species are causing long-lasting economic losses and are endangering food security worldwide. Ongoing events, such as climate change, changes in agricultural practices, globalization of markets or changes in plant virus vector populations, are affecting plant virus life cycles. Because [...] Read more.

Plant viruses infecting crop species are causing long-lasting economic losses and are endangering food security worldwide. Ongoing events, such as climate change, changes in agricultural practices, globalization of markets or changes in plant virus vector populations, are affecting plant virus life cycles. Because farmer’s fields are part of the larger environment, the role of wild plant species in plant virus life cycles can provide information about underlying processes during virus transmission and spread. This review focuses on the Solanaceae family, which contains thousands of species growing all around the world, including crop species, wild flora and model plants for genetic research. In a first part, we analyze various viruses infecting Solanaceae plants across the agro-ecological interface, emphasizing the important role of virus interactions between the cultivated and wild zones as global changes affect these environments on both local and global scales. To cope with these changes, it is necessary to adjust prophylactic protection measures and diagnostic methods. As illustrated in the second part, a complex virus research at the landscape level is necessary to obtain relevant data, which could be overwhelming. Based on evidence from previous studies we conclude that Solanaceae plant communities can be targeted to address complete life cycles of viruses with different life strategies within the agro-ecological interface. Data obtained from such research could then be used to improve plant protection methods by taking into consideration environmental factors that are impacting the life cycles of plant viruses. Full article

(This article belongs to the Special Issue Plant Virus Epidemiology)

12 pages, 7577 KiB

Open AccessEditor’s ChoiceArticle

Silicon Alters Leaf Surface Morphology and Suppresses Insect Herbivory in a Model Grass Species

by Casey R. Hall, Vaibhav Dagg, Jamie M. Waterman and Scott N. Johnson

Plants 2020, 9(5), 643; https://doi.org/10.3390/plants9050643 - 19 May 2020

Cited by 35 | Viewed by 5360

Abstract

Grasses accumulate large amounts of silicon (Si) which is deposited in trichomes, specialised silica cells and cell walls. This may increase leaf toughness and reduce cell rupture, palatability and digestion. Few studies have measured leaf mechanical traits in response to Si, thus the [...] Read more.

Grasses accumulate large amounts of silicon (Si) which is deposited in trichomes, specialised silica cells and cell walls. This may increase leaf toughness and reduce cell rupture, palatability and digestion. Few studies have measured leaf mechanical traits in response to Si, thus the effect of Si on herbivores can be difficult to disentangle from Si-induced changes in leaf surface morphology. We assessed the effects of Si on Brachypodium distachyon mechanical traits (specific leaf area (SLA), thickness, leaf dry matter content (LDMC), relative electrolyte leakage (REL)) and leaf surface morphology (macrohairs, prickle, silica and epidermal cells) and determined the effects of Si on the growth of two generalist insect herbivores (Helicoverpa armigera and Acheta domesticus). Si had no effect on leaf mechanical traits; however, Si changed leaf surface morphology: silica and prickle cells were on average 127% and 36% larger in Si supplemented plants, respectively. Prickle cell density was significantly reduced by Si, while macrohair density remained unchanged. Caterpillars were more negatively affected by Si compared to crickets, possibly due to the latter having a thicker and thus more protective gut lining. Our data show that Si acts as a direct defence against leaf-chewing insects by changing the morphology of specialised defence structures without altering leaf mechanical traits. Full article

(This article belongs to the Special Issue The Role of Silicon in Plant Defences)

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