Search Results (174)

Background/Objectives Galeopsis spp. (Lamiaceae) are widely distributed across extensive areas in Romania, being used mainly for their sedative, neuroprotective, antioxidant, anti-inflammatory, expectorant, astringent, and diuretic properties. The paper reports for the first time the investigation of the total phenolic content (TPC), total flavonoid content (TFC), and phenolic acid profile in the roots, aerial parts, and leaves from three wild-grown Galeopsis spp. (G. bifida Boenn., G. speciosa Mill., and G. tetrahit L.), along with their antioxidant and acetylcholinesterase (AChE) inhibitory potentials. Methods: The ultra-high-performance liquid chromatography/ultraviolet/mass spectrometry (HPLC/UV/MS) method was used for the identification and quantification of key phenolic acids. The spectrophotometric method was applied for the determination of TPC, TFC, 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activities and also the ferric-reducing antioxidant power (FRAP). High-performance thin-layer chromatography (HPTLC) was employed for the assessment of in situ antioxidant (DPPH assay) and AChE inhibitory potentials. Results: Galeopsis spp. exhibit significant polyphenol accumulation. Chlorogenic acid was the most abundant compound, with the highest levels detected in G. tetrahit leaves (22,347.907 ± 1117.395 μg/g), followed by G. tetrahit aerial parts (11,678.509 ± 583.925 μg/g) and G. speciosa leaves (8712.628 ± 435.631 μg/g). G. tetrahit leaves had the highest DDPH radical scavenging activity, with a half-maximal inhibitory concentration (IC₅₀) of 0.458 ± 0.03 mg/mL, demonstrating a markedly stronger antioxidant effect. Leaves consistently showed the strongest DPPH activity across all species, with G. speciosa leaves also displaying a low IC₅₀ value of 0.789 ± 0.03 mg/mL, comparable to G. tetrahit. Aerial parts exhibited an intermediate effect, with G. bifida aerial parts showing an IC₅₀ of 8.102 ± 0.49 mg/mL, while G. tetrahit aerial parts demonstrated stronger activity at 1.511 ± 0.11 mg/mL. AChE inhibition activity increased progressively from the roots to aerial parts to leaves, with leaves consistently exhibiting the strongest inhibitory effects across all Galeopsis spp. G. tetrahit leaves had the strongest inhibition, with an IC₅₀ of 4.002 ± 0.32 mg/mL, followed by G. speciosa leaves (6.92 ± 0.14 mg/mL) and G. bifida leaves (6.97 ± 0.68 mg/mL). Conclusions: Our study provides a comprehensive analysis of the phenolic acid content, in vitro antioxidant activity, and neuroprotective potential of three Galeopsis spp. (G. bifida, G. speciosa, and G. tetrahit) from the southwestern Romanian flora. Full article

The roles of endophytes in Cannabis sativa (cannabis, hemp) remain poorly explored. While in vitro studies suggest that there can be several benefits, such as plant growth promotion and protection against pathogens, more in planta studies are needed. This review summarizes the bacterial and fungal endophytes previously reported in tissues of C. sativa and discusses the factors influencing their presence, as well as their potential beneficial and detrimental effects. Using genome sequencing and culture-based approaches, we describe the microbial diversity in hydroponically cultivated cannabis plants at several developmental stages. These include mother plants, cuttings, vegetative and flowering plants, and tissue-cultured plantlets. Microbes that were present include fungal, yeast, and bacterial endophytes found in roots, stems, leaves, inflorescences, and seeds. These may have originated from the growing substrate or be transmitted through vegetative propagation. Notable endophytes included Rhizophagus irregularis (a mycorrhizal fungus), Penicillium chrysogenum (an antibiotic producer), and various endophytic yeast species not previously described in C. sativa. Endophytes representing potential plant pathogens, such as Fusarium oxysporum, are also present within cannabis tissues, which can negatively impact plant health. Using scanning electron microscopy, we observed that fungal propagules are present within pith parenchyma cells and xylem vessel elements in stem tissues, illustrating for the first time the in situ localization and distribution of endophytes in cannabis vascular tissues. The mechanism of spread through xylem vessels likely contributes to the spread of endophytes within cannabis and hemp plants. Further research is required to validate the roles of endophytes in cannabis and hemp plants grown under commercial production conditions. Full article

In vitro shoot culture and cryopreservation (CP) are techniques essential for the ex situ preservation of genetic resources and the production of plant propagation material of clonally propagated horticultural crops. Changes in plant-associated microbiota diversity and composition induced by in vitro cultivation and CP treatment could have a negative effect on the growth and ex vitro adaptation of the in vitro propagated shoots. Therefore, the aim of the present study was to assess changes in endophytic bacteria diversity in domestic apple tissues induced by in vitro cultivation and CP treatment and to investigate the potential of the bacterial inoculum to improve the rooting and ex vitro acclimatisation of the propagated shoots. Metataxonomic analysis revealed a variation in the endophytic bacteria diversity and taxonomic composition between the field-grown tree dormant bud and the in vitro propagated or CP-treated shoot samples of apple cv. Gala. Whereas Sphingobacteriaceae, Sphingomonadaceae, Pseudomonadaceae, and Beijerinckiaceae families were the most prevalent families in the bud samples, Enterobacteriaceae, Bacillaceae, and Lactobacillaceae were dominant in the in vitro shoots. The bacterial inoculum effect on rooting and ex vitro acclimatisation was assessed using four isolates selected by screening the endophytic isolate collection. Bacillus sp. L3.4, B. toyonensis Nt18, or a combined inoculum resulted in a 21%, 36%, and 59% increase in cumulative root length and a 41%, 46%, and 35% increase in the biomass accumulation of ex vitro acclimatised plantlets, respectively. Root zone microbiota functional diversity analysis implied that growth stimulation was not related to improved nutrient uptake but could involve a pathogen-suppressing effect. The results demonstrate that the application of plant growth-promoting bacteria can potentially improve the performance of the in vitro propagated germplasm. Full article

Endocyn is a root canal irrigant with a stable formulation of hypochlorous acid (HOCl), and should have significant antimicrobial effects. However, there are no available studies that evaluate these effects on different types of bacterial species. In this prospective in vitro study, bacterial species were grown with and without the addition of Endocyn to measure the effects on the Gram-positive bacteria Actinomyces naeslundii, Lactobacillus acidophilus, Streptococcus gordonii, and Streptococcus mutans, as well as the Gram-negative bacteria Porphyromonas gingivalis, Fusobacterium nucleatum, and Veillonella parvula. Turbidity was measured at 24 h, and the differences between the baseline and experimental treatments were measured using two-tailed Student’s t-tests and verified using ANOVA. Gram-positive bacteria were inhibited in the range of −8.2% to −35.5%, p = 0.14 to p = 0.004, while Gram-negative bacteria were inhibited in the range of −16.7% to −41.4%, p = 0.04 to p = 0.001, which were similar to the effects of 5% NaOCl (bleach). These data demonstrated that Gram-positive bacteria were somewhat resistant to Endocyn at lower levels but were inhibited at all higher concentrations, while Gram-negative bacteria were susceptible to Endocyn at all levels, and increased at higher concentrations. These results provide clinically relevant data regarding the efficacy of this disinfectant against common oral pathogens (and commensal bacteria), and are important as they provide evidence regarding public health and the environmental safety of clinical protocols regarding endodontic hygiene. Full article

(1) Background: Humulus lupulus L. plants constitute a rich source of bioactive compounds. The synthesis of bioactive compounds in plants is often triggered by the activation of secondary metabolism, which can be induced by biotic or abiotic elicitors. In vitro, the effect of the elicitors can be studied in a controlled environment and in a small space, independently of seasonal variations. Cytokinins are frequently used in plant tissue culture for bud regeneration, branching and shoot elongation due to their role in cell division enhancement. This study aimed to investigate the effects of different cytokinins on the growth parameters, total (poly)phenolic content and antioxidant capacity of in vitro-grown hop plants to evaluate hop vitro-derived biomass as a potential source of bioactive compounds. (2) Methods: unimodal hop (cvs. Cascade and Columbus) explants were cultured on media enriched with four cytokinins (kinetin, 6-benzylaminopurine, meta-topolin and 6-(γ,γ-dimethylallylamino)-purine) at four concentrations. (3) Results: A genotype-dependent response to different cytokinins was encountered. (4) Conclusions Columbus explants could root in culture media auxin-free, providing valuable opportunities for commercial nurseries. Moreover, cytokinins were confirmed to be valuable elicitors to stimulate the bioactive compound biosynthesis in micropropagated hop plants, making them a precious source for various industries. Full article

Culinary rhubarb is grown for its large, thick leaf petioles. Red-stalked cultivars and selection are more attractive for the fresh market and processing industry. In vitro cultures are important for rapidly multiplying value genotypes and producing plants free of viruses. This study aimed to develop an in vitro propagation method for six rhubarb selections from the Raspberry (R1, R2, R3), Leader (L1, L2), and Karpow Lipskiego (KL) groups. In addition, the planting material of six rhubarb selections was subjected to phytochemical analysis using the HPLC method to assess the content of bioactive compounds. The cultures were initiated from underground buds on the crowns. The initial growth was obtained for 45 to 75% of initial explants because of bacterial contamination and low bud activity of some genotypes. The type and concentration of cytokinin and its interaction with gibberellin acid (GA₃) were shown to have a significant effect on the cyclic multiplication and commercially interesting rate of all rhubarb genotypes. A high in vitro rooting frequency, 93.7 to 95.8% for rhubarb Raspberry, 94.3 to 100% for rhubarb Leader, and 96.7% KP selections were obtained after two-cycle rooting on a medium containing IBA and NAA. The polyphenolic compounds, such as cyanidin-3-O-rutinoside, rhaponticin, resveratrol, caffeic acid, p-coumaric acid, cinnamic acid, syringic acid, and ferulic acid were detected in selected rhubarb genotypes. The highest content of anthocyanins (2.9 mg·1 g⁻¹ DM) and rhaponticin (107.8 µg·1 g⁻¹ DM) was found in Raspberry selections. On the other hand, Leader selections were characterized by the highest content of resveratrol (0.25 µg·1 g⁻¹ DM) and phenolic acids (1.3 µg·1 g⁻¹ DM). The less attractive for functional food production seems to be KL selection. Full article

Kaempferia grandifolia Saensouk & Jenjittikul (Zingiberaceae), a rare plant species in Thailand, is commonly used as a medicinal plant, while the young leaves are cooked and eaten as a vegetable. This study focused on the in vitro propagation of K. grandifolia plants to induce the development of shoots, roots, microrhizomes, and acclimatization. The genetic variations between plants grown under in vitro propagation and plants grown in nature were also assessed. An efficient protocol was developed for in vitro propagation of K. grandifolia using microshoots (0.5 cm in length). The optimal responses for shoot multiplication (4.78 ± 1.15 shoots/explant) and root induction (11.56 ± 1.39 roots/explant) were obtained within 8 weeks in Murashige and Skoog (MS) medium supplemented with 3 mg/L of 6-benzylamino purine (BAP) plus 0.5 mg/L of NAA. Microrhizome induction was 80% when the shoot buds were cultured on MS medium supplemented with 2 mg/L of BAP, 1 mg/L of NAA, 11 µM of silver nitrate (AgNO₃), and 70 g/L of sucrose after 20 weeks. The survival rate of plantlets was 100% when transplanted to soil and sand. Micropropagated and field-grown donor plants of K. grandifolia showed 91.49% genetic similarity through RAPD analysis. Full article

Green mold caused by Penicillium digitatum is a major post-harvest disease in citrus fruits. Therefore, the search for sustainable and low-environmental-impact alternatives for the management of these fungi is of utmost importance. Physalis peruviana L. is a native fruit of the Peruvian Andes with rich bioactive components present throughout the plant. Its antifungal activity stands out, attributed to its high content of phenols, coupled with its antioxidant capacity and antimicrobial activity. Plants were cultivated aeroponically under a combination of red, mixed (50% red, 50% blue), and green LED lights. Additionally, in vitro-habituated roots free of plant growth regulators were also cultivated. An ethanol extraction assisted by ultrasound for 30 min followed by maceration for 72 h was performed, and the extract was filtrated and evaporated in an extraction hood. Antioxidant activity was assessed using the DPPH method, total polyphenols were measured using the Folin–Ciocâlteu method, and an antifungal test in vitro by the poisoned food method was conducted against P. digitatum. In vitro assays revealed that extracts from leaves, roots, and fruits exerted a significant inhibitory effect on the growth of P. digitatum, as evidenced by a reduction in colony radius when cultured employing the poisoned food method, with IC₅₀ values of 62.17, 53.15, and 286.34 µg·mL⁻¹, respectively, compared to 2297 µg·mL⁻¹ for the commercial fungicide Captan 50WP. Although leaves had higher total polyphenol content, no direct correlation with antifungal activity was found. Colored LEDs enhanced phenol accumulation, antioxidant capacity, and antifungal properties in plant parts compared to white LEDs and in vitro roots. These findings suggest P. peruviana as a new alternative biological production system to provide natural compounds for post-harvest disease management. Full article

In recent years, interest in using encapsulated plant growth-promoting rhizobacteria (PGPR) as a biocontrol agent against root-knot nematodes has increased. Root-knot nematodes are soil-borne parasites that mostly cause annual commercial losses globally by infecting tomato plants (Solanum lycopersicum). In this work, tomato plants (cv. GS) were grown in a greenhouse to test the effectiveness of encapsulated Bacillus megaterium with or without humic acid or in liquid form at different inoculum levels against Meloidogyne javanica and their impact on different growth parameters. A scanning electron microscope (SEM) was used to visualize the microencapsulation of B. megaterium as well as viability and protease production In vitro. In a greenhouse experiment, humic acid-encapsulated B. megaterium resulted in a significant decrease in nematode parameters compared to the control group. When compared to other inoculants, the use of 10 capsules/plant decreased nematode infestation and enhanced plant growth parameters, antioxidant enzymes, and photosynthetic pigments. These results are reflected in increased dehydrogenase activity, total bacterial count, and acidic and alkaline phosphatase in soil 30 and 60 days after transplanting. Therefore, to increase the development dynamics of tomato plants and reduce nematode infestation, we advise using B. megaterium capsules supplemented with humic acid. Full article

The screening of plant-derived compounds with anti-cancer properties is a promising strategy to meet the growing need for new, safe and effective anti-cancer drugs. Justicidin B is a plants secondary metabolite that displays anti-cancer properties in several tumor cells. Therefore, it represents a good candidate. We used the 3R-compliant organism Caenorhabditis elegans to evaluate the safety of justicidin B produced by in vitro-grown adventitious roots of Linum lewisii. We showed that a dose of 100 µg/mL justicidin B does not affect worm vitality in either short-term or chronic administration; in contrast, the 200 µg/mL dose induces a lifespan reduction, but only in short-term daily treatment. We attributed this effect to its accumulation in lipofuscin granules in the pharynx as observed through confocal analysis. HPLC analysis confirmed the higher accumulation justicidin B with a 200 µg/mL dose but also revealed the presence of metabolic derivatives that could be responsible for the toxicity. We also demonstrated that the 100 µg/mL dose does not affect worm fertility or development. Our results highlight the safety of justicidin B, supporting its employment in cancer therapy, and encourage the use of a C. elegans model as an appropriate tool to assess compounds’ toxicity before moving to more complex organisms. Full article

A stable tetraploid date palm mutant with the potential for increased fruit size was recovered from a sectorial di-tetraploid chimera via the in vitro culture of flower explants. Callus was induced using 2,4-D, followed by shoot regeneration on a medium containing NAA and BAP and rooting with IBA. Regenerated plantlets, confirmed as tetraploid via flow cytometry, were acclimatized and grown for six years. The leaves of tetraploids exhibited significantly wider petiole bases, thicker rachis and spines, broader leaflets, and a more intense green leaf color compared to diploids. However, leaf length, spine count, and overall leaf number were reduced. This is the first report of successful tetraploid recovery from a chimeric date palm, demonstrating the potential of this technique to generate novel germplasm and highlighting the phenotypic differences associated with tetraploidy in this species. Full article

Cyanobacterial harmful algal blooms (cHABs) are increasing due to eutrophication and climate change, as is irrigation of crops with freshwater contaminated with cHAB toxins. A few studies, mostly in aquatic protists and plants, have investigated the effects of cHAB toxins or cell extracts on various aspects of photosynthesis, with variable effects reported (negative to neutral to positive). We examined the effects of cyanobacterial live cultures and cell extracts (Microcystis aeruginosa or Anabaena flos-aquae) and individual cHAB toxins (anatoxin-a, ANA; beta-methyl-amino-L-alanine, BMAA; lipopolysaccharide, LPS; microcystin-LR, MC-LR) on photosynthesis in intact plants and leaf pieces in corn (Zea mays) and lettuce (Lactuca sativa). In intact plants grown in soil or hydroponically, overall net photosynthesis (P_n), but not Photosystem-II (PSII) electron-transport yield (Φ_PSII), decreased when roots were exposed to cyanobacterial culture (whether with intact cells, cells removed, or cells lysed and removed) or individual toxins in solution (especially ANA, which also decreased rubisco activity); cyanobacterial culture also decreased leaf chlorophyll concentration. In contrast, Φ_PSII decreased in leaf tissue vacuum-infiltrated with cyanobacterial culture or the individual toxins, LPS and MC-LR, though only in illuminated (vs. dark-adapted) leaves, and none of the toxins caused significant decreases in in vitro photosynthesis in thylakoids. Principal component analysis indicated unique overall effects of cyanobacterial culture and each toxin on photosynthesis. Hence, while cHAB toxins consistently impacted plant photosynthesis at ecologically relevant concentrations, the effects varied depending on the toxins and the mode of exposure. Full article

Soybean’s lengthy protocols for transgenic plant production are a bottleneck in the transgenic breeding of this crop. Explants cultured on a medium for an extended duration exhibit unanticipated modifications. Stress-induced somaclonal variations and in vitro contaminations also cause substantial losses of transgenic plants. This effect could potentially be mitigated by direct shoot regeneration without solid media or in-planta transformation. The current study focused primarily on developing a rapid and effective media-free in-planta transformation technique for three soybean genotypes (Wm82) and our newly developed two hybrids, designated as ZX-16 and ZX-3. The whole procedure for a transgenic plant takes the same time as a stable grown seedling. Multiple axillary shoots were regenerated on stable-grown soybean seedlings without the ectopic expression of developmental regulatory genes. An approximate amount of 200 µL medium with a growth regulator was employed for shoot organogenesis and growth. The maximal shoot regeneration percentages in the Wm82 and ZX-3 genotypes were 87.1% and 84.5%, respectively. The stable transformation ranged from 3% to 8.0%, with an average of 5.5%. This approach seems to be the opposite of the hairy root transformation method, which allowed transgenic shoots to be regenerated on normal roots. Further improvement regarding an increase in the transformation efficiency and of this technique for a broad range of soybean genotypes and other dicot species would be extremely beneficial in achieving increased stable transformation. Full article

Salinity is one of the most important abiotic stress factors that affect plant growth and limit agricultural productivity. In this study, the effects of iron (FeNP), silver (AgNP), and silicon dioxide (SiNP) nanoparticles on the morphological and physiological parameters of in vitro boysenberry plants grown under salinity stress (NaCl) were investigated. According to our study results, higher values were obtained from SiNP application in terms of shoot development parameters; FeNP application was found to be more successful for root development; AgNP application was effective in terms of SPAD, leaf relative water content (LRWC), and relative growth rate (RGR); and FeNP application increased superoxide dismutase (SOD) and catalase (CAT) enzyme activities. Salt stress significantly affected root development, SPAD values, LRWC and RGR, and SOD and CAT enzyme activities. As a result, under salt stress conditions, SiNP, FeNP, and AgNP applications can significantly reduce the negative effects of stress and promote the vegetative development of the plant compared to control conditions. Full article

In recent years, interest in Lonicera caerulea production has grown significantly because of its nutritional and pharmaceutical benefits, leading to rapid expansion in its cultivation. L caerulea var. emphyllocalyx is a lesser-known botanical variety. Due to differences between plants of the Lonicera genus and the lack of scientific reports on micropropagation, it is necessary to determine the possibilities of in vitro propagation. The aim of this study was to elaborate a micropropagation protocol of two new breeding clones of Lonicera caerulea var. emphyllocalyx: ‘21–17’ and ‘139–24’. The experiments were carried out on in vitro cultures grown on MS medium supplemented with 1 mg·dm⁻³ BA or 1 mg·dm⁻³ mT. Two types of explants were used during the experiment: nodal fragments (NFs) and shoot-tips (STs). Before acclimatisation, some rooted microshoots were subjected to cooling at 4 °C for 4 weeks. Significantly more ST explants than NF explants started to grow at the proliferation stage. The application of BA resulted in much better proliferation and health of cultures. Cold storage of micropropagated ‘139–24’ plantlets significantly increased their survival in acclimatisation in contrast to ‘21–17’ plantlets but weakened further growth of the plants. In future in vitro studies on L. caerulea var. emphyllocalyx, BA can be used as the primary growth regulator due to its effectiveness and low cost. Nodal fragments should be considered as the main propagation material since they promote better growth rates. Additionally, further research is required to explore the effects of low-temperature storage on the growth and physiology of these plants. The results obtained in this research may contribute to the development of micropropagation technology in the future for L. caerulea var. emphyllocalyx. Full article