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10 pages, 1964 KiB

Open AccessArticle

Local Application of Acibenzolar-S-Methyl Treatment Induces Antiviral Responses in Distal Leaves of Arabidopsis thaliana

by Seiya Ito, Kagari Sakugawa, Fawzia Novianti, Tsutomu Arie and Ken Komatsu

Int. J. Mol. Sci. 2024, 25(3), 1808; https://doi.org/10.3390/ijms25031808 - 2 Feb 2024

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Abstract

Systemic acquired resistance (SAR) is a plant defense mechanism that provides protection against a broad spectrum of pathogens in distal tissues. Recent studies have revealed a concerted function of salicylic acid (SA) and N-hydroxypipecolic acid (NHP) in the establishment of SAR against [...] Read more.

Systemic acquired resistance (SAR) is a plant defense mechanism that provides protection against a broad spectrum of pathogens in distal tissues. Recent studies have revealed a concerted function of salicylic acid (SA) and N-hydroxypipecolic acid (NHP) in the establishment of SAR against bacterial pathogens, but it remains unknown whether NHP is also involved in SAR against viruses. We found that the local application of acibenzolar-S-methyl (ASM), a synthetic analog of SA, suppressed plantago asiatica mosaic virus (PlAMV) infection in the distal leaves of Arabidopsis thaliana. This suppression of infection in untreated distal leaves was observed at 1 day, but not at 3 days, after application. ASM application significantly increased the expression of SAR-related genes, including PR1, SID2, and ALD1 after 1 day of application. Viral suppression in distal leaves after local ASM application was not observed in the sid2-2 mutant, which is defective in isochorismate synthase 1 (ICS1), which is involved in salicylic acid synthesis; or in the fmo1 mutant, which is defective in the synthesis of NHP; or in the SA receptor npr1-1 mutant. Finally, we found that the local application of NHP suppressed PlAMV infection in the distal leaves. These results indicate that the local application of ASM induces antiviral SAR against PlAMV through a mechanism involving NHP. Full article

(This article belongs to the Special Issue Signal Transduction Mechanism in Plant Disease and Immunity)

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18 pages, 2613 KiB

Open AccessArticle

The Homeodomain–Leucine Zipper Subfamily I Contributes to Leaf Age- and Time-Dependent Resistance to Pathogens in Arabidopsis thaliana

by Nami Maeda, Fuko Matsuta, Takaya Noguchi, Ayumu Fujii, Hikaru Ishida, Yudai Kitagawa and Atsushi Ishikawa

Int. J. Mol. Sci. 2023, 24(22), 16356; https://doi.org/10.3390/ijms242216356 - 15 Nov 2023

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Abstract

In Arabidopsis thaliana (Arabidopsis), nonhost resistance (NHR) is influenced by both leaf age and the moment of inoculation. While the circadian clock and photoperiod have been linked to the time-dependent regulation of NHR in Arabidopsis, the mechanism underlying leaf age-dependent NHR remains unclear. [...] Read more.

In Arabidopsis thaliana (Arabidopsis), nonhost resistance (NHR) is influenced by both leaf age and the moment of inoculation. While the circadian clock and photoperiod have been linked to the time-dependent regulation of NHR in Arabidopsis, the mechanism underlying leaf age-dependent NHR remains unclear. In this study, we investigated leaf age-dependent NHR to Pyricularia oryzae in Arabidopsis. Our findings revealed that this NHR type is regulated by both miR156-dependent and miR156-independent pathways. To identify the key players, we utilized rice-FOX Arabidopsis lines and identified the rice HD-Zip I OsHOX6 gene. Notably, OsHOX6 expression confers robust NHR to P. oryzae and Colletotrichum nymphaeae in Arabidopsis, with its effect being contingent upon leaf age. Moreover, we explored the role of AtHB7 and AtHB12, the Arabidopsis closest homologues of OsHOX6, by studying mutants and overexpressors in Arabidopsis–C. higginsianum interaction. AtHB7 and AtHB12 were found to contribute to both penetration resistance and post-penetration resistance to C. higginsianum in a leaf age- and time-dependent manner. These findings highlight the involvement of HD-Zip I AtHB7 and AtHB12, well-known regulators of development and abiotic stress responses, in biotic stress responses in Arabidopsis. Full article

(This article belongs to the Special Issue Signal Transduction Mechanism in Plant Disease and Immunity)

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21 pages, 3016 KiB

Open AccessArticle

Tissue-Specific Hormone Signalling and Defence Gene Induction in an In Vitro Assembly of the Rapeseed Verticillium Pathosystem

by Fatema Binte Hafiz, Joerg Geistlinger, Abdullah Al Mamun, Ingo Schellenberg, Günter Neumann and Wilfried Rozhon

Int. J. Mol. Sci. 2023, 24(13), 10489; https://doi.org/10.3390/ijms241310489 - 22 Jun 2023

Cited by 1 | Viewed by 5180

Abstract

Priming plants with beneficial microbes can establish rapid and robust resistance against numerous pathogens. Here, compelling evidence is provided that the treatment of rapeseed plants with Trichoderma harzianum OMG16 and Bacillus velezensis FZB42 induces defence activation against Verticillium longisporum infection. The relative expressions [...] Read more.

Priming plants with beneficial microbes can establish rapid and robust resistance against numerous pathogens. Here, compelling evidence is provided that the treatment of rapeseed plants with Trichoderma harzianum OMG16 and Bacillus velezensis FZB42 induces defence activation against Verticillium longisporum infection. The relative expressions of the JA biosynthesis genes LOX2 and OPR3, the ET biosynthesis genes ACS2 and ACO4 and the SA biosynthesis and signalling genes ICS1 and PR1 were analysed separately in leaf, stem and root tissues using qRT-PCR. To successfully colonize rapeseed roots, the V. longisporum strain 43 pathogen suppressed the biosynthesis of JA, ET and SA hormones in non-primed plants. Priming led to fast and strong systemic responses of JA, ET and SA biosynthesis and signalling gene expression in each leaf, stem and root tissue. Moreover, the quantification of plant hormones via UHPLC-MS analysis revealed a 1.7- and 2.6-fold increase in endogenous JA and SA in shoots of primed plants, respectively. In roots, endogenous JA and SA levels increased up to 3.9- and 2.3-fold in Vl43-infected primed plants compared to non-primed plants, respectively. Taken together, these data indicate that microbial priming stimulates rapeseed defence responses against Verticillium infection and presumably transduces defence signals from the root to the upper parts of the plant via phytohormone signalling. Full article

(This article belongs to the Special Issue Signal Transduction Mechanism in Plant Disease and Immunity)

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19 pages, 2417 KiB

Open AccessArticle

BSR1, a Rice Receptor-like Cytoplasmic Kinase, Positively Regulates Defense Responses to Herbivory

by Yasukazu Kanda, Tomonori Shinya, Satoru Maeda, Kadis Mujiono, Yuko Hojo, Keisuke Tomita, Kazunori Okada, Takashi Kamakura, Ivan Galis and Masaki Mori

Int. J. Mol. Sci. 2023, 24(12), 10395; https://doi.org/10.3390/ijms241210395 - 20 Jun 2023

Cited by 4 | Viewed by 1858

Abstract

Crops experience herbivory by arthropods and microbial infections. In the interaction between plants and chewing herbivores, lepidopteran larval oral secretions (OS) and plant-derived damage-associated molecular patterns (DAMPs) trigger plant defense responses. However, the mechanisms underlying anti-herbivore defense, especially in monocots, have not been [...] Read more.

Crops experience herbivory by arthropods and microbial infections. In the interaction between plants and chewing herbivores, lepidopteran larval oral secretions (OS) and plant-derived damage-associated molecular patterns (DAMPs) trigger plant defense responses. However, the mechanisms underlying anti-herbivore defense, especially in monocots, have not been elucidated. The receptor-like cytoplasmic kinase Broad-Spectrum Resistance 1 (BSR1) of Oryza sativa L. (rice) mediates cytoplasmic defense signaling in response to microbial pathogens and enhances disease resistance when overexpressed. Here, we investigated whether BSR1 contributes to anti-herbivore defense responses. BSR1 knockout suppressed rice responses triggered by OS from the chewing herbivore Mythimna loreyi Duponchel (Lepidoptera: Noctuidae) and peptidic DAMPs OsPeps, including the activation of genes required for biosynthesis of diterpenoid phytoalexins (DPs). BSR1-overexpressing rice plants exhibited hyperactivation of DP accumulation and ethylene signaling after treatment with simulated herbivory and acquired enhanced resistance to larval feeding. As the biological significance of herbivory-induced accumulation of rice DPs remains unexplained, their physiological activities in M. loreyi were analyzed. The addition of momilactone B, a rice DP, to the artificial diet suppressed the growth of M. loreyi larvae. Altogether, this study revealed that BSR1 and herbivory-induced rice DPs are involved in the defense against chewing insects, in addition to pathogens. Full article

(This article belongs to the Special Issue Signal Transduction Mechanism in Plant Disease and Immunity)

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10 pages, 2219 KiB

Open AccessArticle

Characterization of Disease Resistance Induced by a Pyrazolecarboxylic Acid Derivative in Arabidopsis thaliana

by Michiko Yasuda, Moeka Fujita, Khamsalath Soudthedlath, Miyuki Kusajima, Hideki Takahashi, Tomoya Tanaka, Futo Narita, Tadao Asami, Akiko Maruyama-Nakashita and Hideo Nakashita

Int. J. Mol. Sci. 2023, 24(10), 9037; https://doi.org/10.3390/ijms24109037 - 20 May 2023

Viewed by 1394

Abstract

Systemic acquired resistance (SAR) is a potent innate immunity system in plants that is induced through the salicylic acid (SA)-mediated signaling pathway. Here, we characterized 3-chloro-1-methyl-1H-pyrazole-5-carboxylic acid (CMPA) as an effective SAR inducer in Arabidopsis. The soil drench application of [...] Read more.

Systemic acquired resistance (SAR) is a potent innate immunity system in plants that is induced through the salicylic acid (SA)-mediated signaling pathway. Here, we characterized 3-chloro-1-methyl-1H-pyrazole-5-carboxylic acid (CMPA) as an effective SAR inducer in Arabidopsis. The soil drench application of CMPA enhanced a broad range of disease resistance against the bacterial pathogen Pseudomonas syringae and fungal pathogens Colletotrichum higginsianum and Botrytis cinerea in Arabidopsis, whereas CMPA did not show antibacterial activity. Foliar spraying with CMPA induced the expression of SA-responsible genes such as PR1, PR2 and PR5. The effects of CMPA on resistance against the bacterial pathogen and the expression of PR genes were observed in the SA biosynthesis mutant, however, while they were not observed in the SA-receptor-deficient npr1 mutant. Thus, these findings indicate that CMPA induces SAR by triggering the downstream signaling of SA biosynthesis in the SA-mediated signaling pathway. Full article

(This article belongs to the Special Issue Signal Transduction Mechanism in Plant Disease and Immunity)

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19 pages, 4955 KiB

Open AccessArticle

Importin β1 Mediates Nuclear Entry of EIN2C to Confer the Phloem-Based Defense against Aphids

by Kai Lu, Liyuan Zhang, Lina Qin, Xiaochen Chen, Xiaobing Wang, Meixiang Zhang and Hansong Dong

Int. J. Mol. Sci. 2023, 24(10), 8545; https://doi.org/10.3390/ijms24108545 - 10 May 2023

Cited by 1 | Viewed by 1420

Abstract

Ethylene Insensitive 2 (EIN2) is an integral membrane protein that regulates ethylene signaling towards plant development and immunity by release of its carboxy-terminal functional portion (EIN2C) into the nucleus. The present study elucidates that the nuclear trafficking of EIN2C is induced by importin [...] Read more.

Ethylene Insensitive 2 (EIN2) is an integral membrane protein that regulates ethylene signaling towards plant development and immunity by release of its carboxy-terminal functional portion (EIN2C) into the nucleus. The present study elucidates that the nuclear trafficking of EIN2C is induced by importin β1, which triggers the phloem-based defense (PBD) against aphid infestations in Arabidopsis. In plants, IMPβ1 interacts with EIN2C to facilitate EIN2C trafficking into the nucleus, either by ethylene treatment or by green peach aphid infestation, to confer EIN2-dependent PBD responses, which, in turn, impede the phloem-feeding activity and massive infestation by the aphid. In Arabidopsis, moreover, constitutively expressed EIN2C can complement the impβ1 mutant regarding EIN2C localization to the plant nucleus and the subsequent PBD development in the concomitant presence of IMPβ1 and ethylene. As a result, the phloem-feeding activity and massive infestation by green peach aphid were highly inhibited, indicating the potential value of EIN2C in protecting plants from insect attacks. Full article

(This article belongs to the Special Issue Signal Transduction Mechanism in Plant Disease and Immunity)

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14 pages, 2327 KiB

Open AccessArticle

Oxidative Status of Medicago truncatula Seedlings after Inoculation with Rhizobacteria of the Genus Pseudomonas, Paenibacillus and Sinorhizobium

by Anna Kisiel and Tymoteusz Miller

Int. J. Mol. Sci. 2023, 24(5), 4781; https://doi.org/10.3390/ijms24054781 - 1 Mar 2023

Cited by 1 | Viewed by 1127

Abstract

An increasing number of scientists working to raise agricultural productivity see the potential in the roots and the soil adjacent to them, together with a wealth of micro-organisms. The first mechanisms activated in the plant during any abiotic or biotic stress concern changes [...] Read more.

An increasing number of scientists working to raise agricultural productivity see the potential in the roots and the soil adjacent to them, together with a wealth of micro-organisms. The first mechanisms activated in the plant during any abiotic or biotic stress concern changes in the oxidative status of the plant. With this in mind, for the first time, an attempt was made to check whether the inoculation of seedlings of the model plant Medicago truncatula with rhizobacteria belonging to the genus Pseudomonas (P. brassicacearum KK5, P. corrugata KK7), Paenibacillus borealis KK4 and a symbiotic strain Sinorhizobium meliloti KK13 would change the oxidative status in the days following inoculation. Initially, an increase in H₂O₂ synthesis was observed, which led to an increase in the activity of antioxidant enzymes responsible for regulating hydrogen peroxide levels. The main enzyme involved in the reduction of H₂O₂ content in the roots was catalase. The observed changes indicate the possibility of using the applied rhizobacteria to induce processes related to plant resistance and thus to ensure protection against environmental stress factors. In the next stages, it seems reasonable to check whether the initial changes in the oxidative state affect the activation of other pathways related to plant immunity. Full article

(This article belongs to the Special Issue Signal Transduction Mechanism in Plant Disease and Immunity)

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14 pages, 2336 KiB

Open AccessArticle

Enhanced Resistance to Fungal and Bacterial Diseases Due to Overexpression of BSR1, a Rice RLCK, in Sugarcane, Tomato, and Torenia

by Satoru Maeda, Wataru Ackley, Naoki Yokotani, Katsutomo Sasaki, Norihiro Ohtsubo, Kenji Oda and Masaki Mori

Int. J. Mol. Sci. 2023, 24(4), 3644; https://doi.org/10.3390/ijms24043644 - 11 Feb 2023

Cited by 5 | Viewed by 1668

Abstract

Sugarcane smut caused by Sporisorium scitamineum is one of the most devastating sugarcane diseases. Furthermore, Rhizoctonia solani causes severe diseases in various crops including rice, tomato, potato, sugar beet, tobacco, and torenia. However, effective disease-resistant genes against these pathogens have not been identified [...] Read more.

Sugarcane smut caused by Sporisorium scitamineum is one of the most devastating sugarcane diseases. Furthermore, Rhizoctonia solani causes severe diseases in various crops including rice, tomato, potato, sugar beet, tobacco, and torenia. However, effective disease-resistant genes against these pathogens have not been identified in target crops. Therefore, the transgenic approach can be used since conventional cross-breeding is not applicable. Herein, the overexpression of BROAD-SPECTRUM RESISTANCE 1 (BSR1), a rice receptor-like cytoplasmic kinase, was conducted in sugarcane, tomato and torenia. BSR1-overexpressing tomatoes exhibited resistance to the bacteria Pseudomonas syringae pv. tomato DC3000 and the fungus R. solani, whereas BSR1-overexpressing torenia showed resistance to R. solani in the growth room. Additionally, BSR1 overexpression conferred resistance to sugarcane smut in the greenhouse. These three BSR1-overexpressing crops exhibited normal growth and morphologies except in the case of exceedingly high levels of overexpression. These results indicate that BSR1 overexpression is a simple and effective tool for conferring broad-spectrum disease resistance to many crops. Full article

(This article belongs to the Special Issue Signal Transduction Mechanism in Plant Disease and Immunity)

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15 pages, 17859 KiB

Open AccessArticle

Proteomic Profiling of Plant and Pathogen Interaction on the Leaf Epidermis

by Yasir Sidiq, Daisuke Tamaoki and Takumi Nishiuchi

Int. J. Mol. Sci. 2022, 23(20), 12171; https://doi.org/10.3390/ijms232012171 - 12 Oct 2022

Cited by 1 | Viewed by 1722

Abstract

The plant epidermis is the first line of plant defense against pathogen invasion, and likely contains important regulatory proteins related to the plant–pathogen interaction. This study aims to identify the candidates of these regulatory proteins expressed in the plant epidermis. We performed comparative [...] Read more.

The plant epidermis is the first line of plant defense against pathogen invasion, and likely contains important regulatory proteins related to the plant–pathogen interaction. This study aims to identify the candidates of these regulatory proteins expressed in the plant epidermis. We performed comparative proteomic studies to identify rapidly and locally expressed proteins in the leaf epidermis inoculated with fungal phytopathogen. The conidia solutions were dropped onto the Arabidopsis leaf surface, and then, we collected the epidermal tissues from inoculated and mock-treated leaves at 4 and 24 hpi. The label-free quantification methods showed that expressions of Arabidopsis proteins, which are related to defense signals, such as BAK1, MKK5, receptor-like protein kinases, transcription factors, and stomatal functions, were rapidly induced in the epidermal tissues of inoculated leaves. In contrast, most of them were not differentially regulated by fugal inoculation in the whole leaves. These findings clearly indicate that epidermal proteomics can monitor locally expressed proteins in inoculated areas of plant tissues. We also identified the 61 fungal proteins, including effector-like proteins specifically expressed on the Arabidopsis epidermis. Our new findings suggested that epidermal proteomics is useful for understanding the local expressions of plant and fungal proteins related to their interactions. Full article

(This article belongs to the Special Issue Signal Transduction Mechanism in Plant Disease and Immunity)

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