scholarly journals Ethylene and Jasmonic Acid Signaling Affect the NPR1-Independent Expression of Defense Genes Without Impacting Resistance to Pseudomonas syringae and Peronospora parasitica in the Arabidopsis ssi1 Mutant

2003 ◽  
Vol 16 (7) ◽  
pp. 588-599 ◽  
Author(s):  
Ashis Nandi ◽  
Pradeep Kachroo ◽  
Hirotada Fukushige ◽  
David F. Hildebrand ◽  
Daniel F. Klessig ◽  
...  
Keyword(s):  
Jasmonic Acid ◽  
Plant Defense ◽  
Pseudomonas Syringae ◽  
Defense Mechanism ◽  
Constitutive Expression ◽  
Defense Responses ◽  
Peronospora Parasitica ◽  
Defense Genes ◽  
Pr Genes ◽  
Ja Signaling

Salicylic acid (SA), ethylene, and jasmonic acid (JA) are important signaling molecules in plant defense to biotic stress. An intricate signaling network involving SA, ethylene, and JA fine tunes plant defense responses. SA-dependent defense responses in Arabidopsis thaliana are mediated through NPR1-dependent and -independent mechanisms. We have previously shown that activation of an NPR1-independent defense mechanism confers enhanced disease resistance and constitutive expression of the pathogenesis-related (PR) genes in the Arabidopsis ssi1 mutant. In addition, the ssi1 mutant constitutively expresses the defensin gene PDF1.2. Moreover, SA is required for the ssi1-conferred constitutive expression of PDF1.2 in addition to PR genes. Hence, the ssi1 mutant appears to target a step common to SA- and ethylene- or JA-regulated defense pathways. In the present study, we show that, in addition to SA, ethylene and JA signaling also are required for the ssi1-conferred constitutive expression of PDF1.2 and the NPR1-independent expression of PR-1. Furthermore, the ethylene-insensitive ein2 and JA-insensitive jar1 mutants enhance susceptibility of ssi1 plants to the necrotrophic fungus Botrytis cinerea. However, defects in either the ethylene- or JA-signaling pathways do not compromise ssi1-conferred resistance to the bacterial pathogen Pseudomonas syringae pv. maculicola and the oomycete pathogen Peronospora parasitica. Interestingly, ssi1 exhibits a marginal increase in the levels of ethylene and JA, suggesting that low endogenous levels of these phytohormones are sufficient to activate expression of defense genes. Taken together, our results indicate that although cross talk in ssi1 renders expression of ethylene- or JA-responsive defense genes sensitive to SA and vice versa, it does not affect downstream signaling leading to resistance.

scholarly journals Jasmonic Acid at the Crossroads of Plant Immunity and Pseudomonas syringae Virulence

2020 ◽  
Vol 21 (20) ◽  
pp. 7482
Author(s):  
Aarti Gupta ◽  
Mamta Bhardwaj ◽  
Lam-Son Phan Tran
Keyword(s):  
Jasmonic Acid ◽  
Plant Defense ◽  
Pseudomonas Syringae ◽  
Regulatory Networks ◽  
Genetic Manipulation ◽  
Plant Immunity ◽  
Stomatal Closure ◽  
Defense Responses ◽  
Plant Defense Responses ◽  
Callose Deposition

Sensing of pathogen infection by plants elicits early signals that are transduced to affect defense mechanisms, such as effective blockage of pathogen entry by regulation of stomatal closure, cuticle, or callose deposition, change in water potential, and resource acquisition among many others. Pathogens, on the other hand, interfere with plant physiology and protein functioning to counteract plant defense responses. In plants, hormonal homeostasis and signaling are tightly regulated; thus, the phytohormones are qualified as a major group of signaling molecules controlling the most widely tinkered regulatory networks of defense and counter-defense strategies. Notably, the phytohormone jasmonic acid mediates plant defense responses to a wide array of pathogens. In this review, we present the synopsis on the jasmonic acid metabolism and signaling, and the regulatory roles of this hormone in plant defense against the hemibiotrophic bacterial pathogen Pseudomonas syringae. We also elaborate on how this pathogen releases virulence factors and effectors to gain control over plant jasmonic acid signaling to effectively cause disease. The findings discussed in this review may lead to ideas for the development of crop cultivars with enhanced disease resistance by genetic manipulation.

scholarly journals The Cuticle Mutant eca2 Modifies Plant Defense Responses to Biotrophic and Necrotrophic Pathogens and Herbivory Insects

2018 ◽  
Vol 31 (3) ◽  
pp. 344-355 ◽  
Author(s):  
Catherine Blanc ◽  
Fania Coluccia ◽  
Floriane L’Haridon ◽  
Martha Torres ◽  
Marlene Ortiz-Berrocal ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Defense Mechanism ◽  
Induced Defense ◽  
Constitutive Expression ◽  
Bacterial Pathogen ◽  
Transcriptional Response ◽  
Chemical Characterization ◽  
Biotic Interactions ◽  
Defense Responses ◽  
Herbivorous Insect

We isolated previously several Arabidopsis thaliana mutants with constitutive expression of the early microbe-associated molecular pattern–induced gene ATL2, named eca (expresión constitutiva de ATL2). Here, we further explored the interaction of eca mutants with pest and pathogens. Of all eca mutants, eca2 was more resistant to a fungal pathogen (Botrytis cinerea) and a bacterial pathogen (Pseudomonas syringae) as well as to a generalist herbivorous insect (Spodoptera littoralis). Permeability of the cuticle is increased in eca2; chemical characterization shows that eca2 has a significant reduction of both cuticular wax and cutin. Additionally, we determined that eca2 did not display a similar compensatory transcriptional response, compared with a previously characterized cuticular mutant, and that resistance to B. cinerea is mediated by the priming of the early and late induced defense responses, including salicylic acid– and jasmonic acid–induced genes. These results suggest that ECA2-dependent responses are involved in the nonhost defense mechanism against biotrophic and necrotrophic pathogens and against a generalist insect by modulation and priming of innate immunity and late defense responses. Making eca2 an interesting model to characterize the molecular basis for plant defenses against different biotic interactions and to study the initial events that take place in the cuticle surface of the aerial organs.

scholarly journals Sucrose-Mediated Priming of Plant Defense Responses and Broad-Spectrum Disease Resistance by Overexpression of the Maize Pathogenesis-Related PRms Protein in Rice Plants

2007 ◽  
Vol 20 (7) ◽  
pp. 832-842 ◽  
Author(s):  
Jorge Gómez-Ariza ◽  
Sonia Campo ◽  
Mar Rufat ◽  
Montserrat Estopà ◽  
Joaquima Messeguer ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Plant Defense ◽  
Broad Spectrum ◽  
Fusarium Verticillioides ◽  
Defense Responses ◽  
Defense Genes ◽  
Pr Genes ◽  
Rice Plants ◽  
Pathogenesis Related ◽  
Mediated Priming

Expression of pathogenesis-related (PR) genes is part of the plant's natural defense response against pathogen attack. The PRms gene encodes a fungal-inducible PR protein from maize. Here, we demonstrate that expression of PRms in transgenic rice confers broad-spectrum protection against pathogens, including fungal (Magnaporthe oryzae, Fusarium verticillioides, and Helminthosporium oryzae) and bacterial (Erwinia chrysanthemi) pathogens. The PRms-mediated disease resistance in rice plants is associated with an enhanced capacity to express and activate the natural plant defense mechanisms. Thus, PRms rice plants display a basal level of expression of endogenous defense genes in the absence of the pathogen. PRms plants also exhibit stronger and quicker defense responses during pathogen infection. We also have found that sucrose accumulates at higher levels in leaves of PRms plants. Sucrose responsiveness of rice defense genes correlates with the pathogen-responsive priming of their expression in PRms rice plants. Moreover, pretreatment of rice plants with sucrose enhances resistance to M. oryzae infection. Together, these results support a sucrose-mediated priming of defense responses in PRms rice plants which results in broad-spectrum disease resistance.

scholarly journals Isolation of Arabidopsis Mutants With Enhanced Disease Susceptibility by Direct Screening

Genetics ◽  
1996 ◽  
Vol 143 (2) ◽  
pp. 973-982 ◽  
Author(s):  
Jane Glazebrook ◽  
Elizabeth E Rogers ◽  
Frederick M Ausubel
Keyword(s):  
Plant Defense ◽  
Pseudomonas Syringae ◽  
Disease Susceptibility ◽  
Bacterial Pathogen ◽  
Defense Responses ◽  
Screening Strategy ◽  
Genetic Dissection ◽  
Plant Defense Responses ◽  
Defense Genes ◽  
Increased Susceptibility

Abstract To discover which components of plant defense responses make significant contributions to limiting pathogen attack, we screened a mutagenized population of Arabidopsis thalzana for individuals that exhibit increased susceptibility to the moderately virulent bacterial pathogen Pseudomonas syringae pv. maculicola ES4326 (Psm ES4326). The 12 enhanced disease susceptibility (eds) mutants isolated included alleles of two genes involved in phytoalexin biosynthesis (pad2, which had been identified previously, and pad4, which had not been identified previously), two alleles of the previously identified npr1 gene, which affects expression of other defense genes, and alleles of seven previously unidentified genes of unknown function. The npr-1 mutations caused greatly reduced expression of the PRI gene in response to PsmES4326 infection, but had little effect on expression of two other defense genes, BGL2 and PR5, suggesting that PR1 expression may be important for limiting growth of PsmES4326. While direct screens for mutants with quantitative pathogen-susceptibility phenotypes have not been reported previously, our finding that mutants isolated in this way include those affected in known defense responses supports the notion that this type of screening strategy allows genetic dissection of the roles of various plant defense responses in disease resistance.

scholarly journals An efficient direct screening system for microorganisms that activate plant immune responses based on plant–microbe interactions using cultured plant cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mari Kurokawa ◽  
Masataka Nakano ◽  
Nobutaka Kitahata ◽  
Kazuyuki Kuchitsu ◽  
Toshiki Furuya
Keyword(s):  
Immune Responses ◽  
Plant Defense ◽  
Pseudomonas Syringae ◽  
Large Scale ◽  
Plant Cells ◽  
Defense Responses ◽  
Root Tip ◽  
General Strategy ◽  
Plant Defense Responses ◽  
Microbe Interactions

AbstractMicroorganisms that activate plant immune responses have attracted considerable attention as potential biocontrol agents in agriculture because they could reduce agrochemical use. However, conventional methods to screen for such microorganisms using whole plants and pathogens are generally laborious and time consuming. Here, we describe a general strategy using cultured plant cells to identify microorganisms that activate plant defense responses based on plant–microbe interactions. Microbial cells were incubated with tobacco BY-2 cells, followed by treatment with cryptogein, a proteinaceous elicitor of tobacco immune responses secreted by an oomycete. Cryptogein-induced production of reactive oxygen species (ROS) in BY-2 cells served as a marker to evaluate the potential of microorganisms to activate plant defense responses. Twenty-nine bacterial strains isolated from the interior of Brassica rapa var. perviridis plants were screened, and 8 strains that enhanced cryptogein-induced ROS production in BY-2 cells were selected. Following application of these strains to the root tip of Arabidopsis seedlings, two strains, Delftia sp. BR1R-2 and Arthrobacter sp. BR2S-6, were found to induce whole-plant resistance to bacterial pathogens (Pseudomonas syringae pv. tomato DC3000 and Pectobacterium carotovora subsp. carotovora NBRC 14082). Pathogen-induced expression of plant defense-related genes (PR-1, PR-5, and PDF1.2) was enhanced by the pretreatment with strain BR1R-2. This cell–cell interaction-based platform is readily applicable to large-scale screening for microorganisms that enhance plant defense responses under various environmental conditions.

Elicitor Recognition and Signal Transduction in Plant Defense Gene Activation

1990 ◽  
Vol 45 (6) ◽  
pp. 569-575 ◽  
Author(s):  
Dierk Scheel ◽  
Jane E. Parker
Keyword(s):  
Signal Transduction ◽  
Plant Defense ◽  
Transcriptional Activation ◽  
Molecular Mechanisms ◽  
Plant Protection ◽  
Plant Cells ◽  
Defense Responses ◽  
Plant Defense Responses ◽  
Defense Genes ◽  
Plant Defense Genes

Abstract Plants defend themselves against pathogen attack by activating a whole set of defense responses, most of them relying on transcriptional activation of plant defense genes. The same responses are induced by treatment of plant cells with elicitors released from the pathogen or from the plant surface. Several plant/elicitor combinations have been used successfully as experimental systems to investigate the molecular basis of plant defense responses. Receptor-like structures on the plasma membrane of plant cells appear to bind the elicitors. Thereby, intracellular signal transduction chains are initiated which finally result in the activation of plant defense genes. A better understanding of the molecular mechanisms of early processes in plant defense responses, as provided by these studies, may in the long term help to develop environmentally safe plant protection methods for agriculture.

scholarly journals Foliar Application or Seed Priming of Cholic Acid-Glycine Conjugates can Mitigate/Prevent the Rice Bacterial Leaf Blight Disease via Activating Plant Defense Genes

2021 ◽  
Vol 12 ◽  
Author(s):  
Garima Pal ◽  
Devashish Mehta ◽  
Saurabh Singh ◽  
Kalai Magal ◽  
Siddhi Gupta ◽  
...  
Keyword(s):  
Plant Defense ◽  
Cholic Acid ◽  
Foliar Application ◽  
Bacterial Load ◽  
Crop Protection ◽  
Seed Priming ◽  
Defense Responses ◽  
Defense Genes ◽  
Plant Defense Genes ◽  
Blight Disease

Xanthomonas Oryzae pv. oryzae (Xoo) causes bacterial blight and Rhizoctonia solani (R. solani) causes sheath blight in rice accounting for >75% of crop losses. Therefore, there is an urgent need to develop strategies for the mitigation of these pathogen infections. In this study, we report the antimicrobial efficacy of Cholic Acid-Glycine Conjugates (CAGCs) against Xoo and R. solani. We show that CAGC C6 is a broad-spectrum antimicrobial and is also able to degrade biofilms. The application of C6 did not hamper plant growth and showed minimal effect on the plant cell membranes. Exogenous application of C6 on pre-infection or post-infection of Xoo on rice susceptible genotype Taichung native (TN1) can mitigate the bacterial load and improve resistance through upregulation of plant defense genes. We further demonstrate that C6 can induce plant defense responses when seeds were primed with C6 CAGC. Therefore, this study demonstrates the potential of CAGCs as effective antimicrobials for crop protection that can be further explored for field applications.

scholarly journals Comprehensive Identification of PTI Suppressors in Type III Effector Repertoire Reveals that Ralstonia solanacearum Activates Jasmonate Signaling at Two Different Steps

2019 ◽  
Vol 20 (23) ◽  
pp. 5992 ◽  
Author(s):  
Masahito Nakano ◽  
Takafumi Mukaihara
Keyword(s):  
Pseudomonas Syringae ◽  
Cysteine Protease ◽  
Ralstonia Solanacearum ◽  
Acid Synthesis ◽  
Defense Responses ◽  
Dependent Manner ◽  
Jaz Proteins ◽  
Ros Burst ◽  
Ja Signaling ◽  
Activity Dependent

Ralstonia solanacearum is the causative agent of bacterial wilt in many plants. To identify R. solanacearum effectors that suppress pattern-triggered immunity (PTI) in plants, we transiently expressed R. solanacearum RS1000 effectors in Nicotiana benthamiana leaves and evaluated their ability to suppress the production of reactive oxygen species (ROS) triggered by flg22. Out of the 61 effectors tested, 11 strongly and five moderately suppressed the flg22-triggered ROS burst. Among them, RipE1 shared homology with the Pseudomonas syringae cysteine protease effector HopX1. By yeast two-hybrid screening, we identified jasmonate-ZIM-domain (JAZ) proteins, which are transcriptional repressors of the jasmonic acid (JA) signaling pathway in plants, as RipE1 interactors. RipE1 promoted the degradation of JAZ repressors and induced the expressions of JA-responsive genes in a cysteine–protease-activity-dependent manner. Simultaneously, RipE1, similarly to the previously identified JA-producing effector RipAL, decreased the expression level of the salicylic acid synthesis gene that is required for the defense responses against R. solanacearum. The undecuple mutant that lacks 11 effectors with a strong PTI suppression activity showed reduced growth of R. solanacearum in Nicotiana plants. These results indicate that R. solanacearum subverts plant PTI responses using multiple effectors and manipulates JA signaling at two different steps to promote infection.

scholarly journals The Cotton Ghplp2 Positively Regulates Plant Defense against Verticillium Dahliae by Modulating Fatty Acid Accumulation and Jasmonic Acid Signaling Pathway

2021 ◽  
Author(s):  
Yutao Zhu ◽  
Xiaoqian Hu ◽  
Yujiao Jia ◽  
Linying Gao ◽  
Yakun Pei ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Linoleic Acid ◽  
Jasmonic Acid ◽  
Plant Defense ◽  
Signaling Pathway ◽  
Linolenic Acid ◽  
Verticillium Dahliae ◽  
Transgenic Arabidopsis ◽  
Cotton Plants ◽  
Ja Signaling

Abstract Patatin-like proteins (PLPs) have nonspecific lipid acyl hydrolyze (LAH) activity, which can hydrolyze membrane lipids into fatty acids and lysophospholipids. The vital role of PLPs in plant growth and abiotic stress has been well elucidated. However, the function of PLPs in plant defense response against pathogens is still poorly understood. Here, we isolated and identified a novel cotton (Gossypium hirsutum) patatin-like protein gene GhPLP2. GhPLP2 expression was induced upon treatment with pathogens Verticillium dahliae, Fusarium xysporum, and signaling molecules jasmonic acid (JA), ethylene in cotton plants. Subcellular localization revealed that GhPLP2 was localized in the cell wall and plasma membrane. GhPLP2-silenced cotton plants showed reduced resistance to V. dahliae infection, while overexpression of GhPLP2 in Arabidopsis enhanced the resistance to V. dahliae, with mild symptoms, decreased disease index, and fungal biomass. Hypersensitive response, callose deposition, and H2O2 accumulation triggered by V. dahlia elicitor were reduced in silenced cotton plants. GhPLP2-transgenic Arabidopsis had more accumulation of JA and JA synthesis precursor linoleic acid (LA, 18:2) and α-linolenic acid (ALA, 18:3) than control plants. Consistently, linoleic acid, α-linolenic acid, and jasmonic acid have decreased in GhPLP2-silenced cotton plants. Further, the gene expression of the JA signaling pathway is up-regulated in transgenic Arabidopsis and down-regulated in silenced cotton plants, respectively. These results showed that GhPLP2 is involved in plants' resistance to V. dahliae by maintaining fatty acid metabolism pools for JA biosynthesis and activation of the JA signaling pathway.

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