scholarly journals Constitutive activity of the Arabidopsis MAP Kinase 3 confers resistance to Pseudomonas syringae and drives robust immune responses

2017 ◽  
Vol 12 (8) ◽  
pp. e1356533 ◽  
Author(s):  
Julien Lang ◽  
Baptiste Genot ◽  
Heribert Hirt ◽  
Jean Colcombet
Keyword(s):  
Immune Responses ◽  
Map Kinase ◽  
Pseudomonas Syringae ◽  
Constitutive Activity

scholarly journals molecular link from PAMP perception to a MAPK cascade associated with tomato disease resistance

2012 ◽  
Author(s):  
Guido Sessa ◽  
Gregory B. Martin
Keyword(s):  
Cell Death ◽  
Disease Resistance ◽  
Immune Responses ◽  
Map Kinase ◽  
Pseudomonas Syringae ◽  
Molecular Mechanisms ◽  
Plant Immunity ◽  
Defense Responses ◽  
Research Activities ◽  
Mapk Cascades

The research problem: The detection of pathogen-associated molecular patterns (PAMPs) by plant pattern recognition receptors (PRRs) is a key mechanism by which plants activate an effective immune response against pathogen attack. MAPK cascades are important signaling components downstream of PRRs that transduce the PAMP signal to activate various defense responses. Preliminary experiments suggested that the receptor-like cytoplasmickinase (RLCK) Mai5 plays a positive role in pattern-triggered immunity (PTI) and interacts with the MAPKKK M3Kε. We thus hypothesized that Mai5, as other RLCKs, functions as a component PRR complexes and acts as a molecular link between PAMP perception and activation of MAPK cascades. Original goals: The central goal of this research was to investigate the molecular mechanisms by which Mai5 and M3Kε regulate plant immunity. Specific objectives were to: 1. Determine the spectrum of PAMPs whose perception is transmitted by M3Kε; 2. Identify plant proteins that act downstream of M3Kε to mediate PTI; 3. Investigate how and where Mai5 interacts with M3Kε in the plant cell; 4. Examine the mechanism by which Mai5 contributes to PTI. Changes in research directions: We did not find convincing evidence for the involvement of M3Kε in PTI signaling and substituted objectives 1 and 3 with research activities aimed at the analysis of transcriptomic profiles of tomato plants during the onset of plant immunity, isolation of the novel tomato PRR FLS3, and investigation of the involvement of the RLCKBSKs in PTI. Main achievements during this research program are in the following major areas: 1. Functional characterization of Mai5. The function of Mai5 in PTI signaling was demonstrated by testing the effect of silencing the Mai5 gene by virus-induced gene silencing (VIGS) experiments and in cell death assays. Domains of Mai5 that interact with MAPKKKs and subcellular localization of Mai5 were analyzed in detail. 2. Analysis of transcriptional profiles during the tomato immune responses to Pseudomonas syringae (Pombo et al., 2014). We identified tomato genes whose expression is induced specifically in PTI or in effector-triggered immunity (ETI). Thirty ETI-specific genes were examined by VIGS for their involvement in immunity and the MAPKKK EPK1, was found to be required for ETI. 3. Dissection of MAP kinase cascades downstream of M3Kε (Oh et al., 2013; Teper et al., 2015). We identified genes that encode positive (SGT and EDS1) and negative (WRKY1 and WRKY2) regulators of the ETI-associated cell death mediated by M3Kε. In addition, the MKK2 MAPKK, which acts downstream of M3Kε, was found to interact with the MPK3 MAPK and specific MPK3 amino acids involved interaction were identified and found to be required for induction of cell death. We also identified 5 type III effectors of the bacterial pathogen Xanthomonaseuvesicatoria that inhibited cell death induced by components of ETI-associated MAP kinase cascades. 4. Isolation of the tomato PRR FLS3 (Hind et al., submitted). FLS3, a novel PRR of the LRR-RLK family that specifically recognizes the flagellinepitope flgII-28 was isolated. FLS3 was shown to bind flgII-28, to require kinase activity for function, to act in concert with BAK1, and to enhance disease resistance to Pseudomonas syringae. 5. Functional analysis of RLCKs of the brassinosteroid signaling kinase (BSK) family.Arabidopsis and tomato BSKs were found to interact with PRRs. In addition, certain ArabidospsisBSK mutants were found to be impaired in PAMP-induced resistance to Pseudomonas syringae. Scientific and agricultural significance: Our research activities discovered and characterized new molecular components of signaling pathways mediating recognition of invading pathogens and activation of immune responses against them. Increased understanding of molecular mechanisms of immunity will allow them to be manipulated by both molecular breeding and genetic engineering to produce plants with enhanced natural defense against disease.

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.

scholarly journals BAK1 Is Not a Target of the Pseudomonas syringae Effector AvrPto

2011 ◽  
Vol 24 (1) ◽  
pp. 100-107 ◽  
Author(s):  
Tingting Xiang ◽  
Na Zong ◽  
Jie Zhang ◽  
Jinfeng Chen ◽  
Mingsheng Chen ◽  
...  
Keyword(s):  
Cell Surface ◽  
Immune Responses ◽  
Pseudomonas Syringae ◽  
Plant Cell ◽  
Crucial Role ◽  
Pathogenic Bacteria ◽  
Effector Proteins ◽  
Receptor Like Kinase ◽  
Receptor Kinases ◽  
New Evidence

Plant cell surface-localized receptor kinases such as FLS2, EFR, and CERK1 play a crucial role in detecting invading pathogenic bacteria. Upon stimulation by bacterium-derived ligands, FLS2 and EFR interact with BAK1, a receptor-like kinase, to activate immune responses. A number of Pseudomonas syringae effector proteins are known to block immune responses mediated by these receptors. Previous reports suggested that both FLS2 and BAK1 could be targeted by the P. syringae effector AvrPto to inhibit plant defenses. Here, we provide new evidence further supporting that FLS2 but not BAK1 is targeted by AvrPto in plants. The AvrPto-FLS2 interaction prevented the phosphorylation of BIK1, a downstream component of the FLS2 pathway.

scholarly journals Disruption of PAMP-Induced MAP Kinase Cascade by a Pseudomonas syringae Effector Activates Plant Immunity Mediated by the NB-LRR Protein SUMM2

2012 ◽  
Vol 11 (3) ◽  
pp. 253-263 ◽  
Author(s):  
Zhibin Zhang ◽  
Yaling Wu ◽  
Minghui Gao ◽  
Jie Zhang ◽  
Qing Kong ◽  
...  
Keyword(s):  
Map Kinase ◽  
Pseudomonas Syringae ◽  
Plant Immunity ◽  
Map Kinase Cascade ◽  
Kinase Cascade ◽  
Lrr Protein

scholarly journals Bacillus subtilis and Pseudomonas fluorescens Trigger Common and Distinct Systemic Immune Responses in Arabidopsis thaliana Depending on the Pathogen Lifestyle

Vaccines ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 503
Author(s):  
Ngoc Huu Nguyen ◽  
Patricia Trotel-Aziz ◽  
Sandra Villaume ◽  
Fanja Rabenoelina ◽  
Adrian Schwarzenberg ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Immune Responses ◽  
Signaling Pathways ◽  
Pseudomonas Syringae ◽  
Systemic Resistance ◽  
Functional Study ◽  
Marker Genes ◽  
Beneficial Bacteria ◽  
Bacillus Spp ◽  
Immune Pathways

Plants harbor various beneficial bacteria that modulate their innate immunity, resulting in induced systemic resistance (ISR) against various pathogens. However, the immune mechanisms underlying ISR triggered by Bacillus spp. and Pseudomonas spp. against pathogens with different lifestyles are not yet clearly elucidated. Here, we show that root drenching of Arabidopsis plants with Pseudomonas fluorescensPTA-CT2 and Bacillus subtilis PTA-271 can induce ISR against the necrotrophic fungus B. cinerea and the hemibiotrophic bacterium Pseudomonas syringae Pst DC3000. In the absence of pathogen infection, both beneficial bacteria do not induce any consistent change in systemic immune responses. However, ISR relies on priming faster and robust expression of marker genes for the salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) signaling pathways upon pathogen challenge. These responses are also associated with increased levels of SA, JA, and abscisic acid (ABA) in the leaves of bacterized plants after infection. The functional study also points at priming of the JA/ET and NPR1-dependent defenses as prioritized immune pathways in ISR induced by both beneficial bacteria against B. cinerea. However, B. subtilis-triggered ISR against Pst DC3000 is dependent on SA, JA/ET, and NPR1 pathways, whereas P. fluorescens-induced ISR requires JA/ET and NPR1 signaling pathways. The use of ABA-insensitive mutants also pointed out the crucial role of ABA signaling, but not ABA concentration, along with JA/ET signaling in primed systemic immunity by beneficial bacteria against Pst DC3000, but not against B. cinerea. These results clearly indicate that ISR is linked to priming plants for enhanced common and distinct immune pathways depending on the beneficial strain and the pathogen lifestyle.

Delineating the functional roles of dynamin related proteins in plant innate immunity

2015 ◽  
Author(s):  
◽  
John M. Smith
Keyword(s):  
Innate Immunity ◽  
Immune Responses ◽  
Pseudomonas Syringae ◽  
Potential Role ◽  
Vesicular Trafficking ◽  
Microbial Pathogens ◽  
University Of Missouri ◽  
Functional Roles ◽  
The University ◽  
Related Proteins

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Vesicular trafficking mediates the movement of cargo molecules from donor to target organelles and is emerging as a critical means by which plants modulate immune responses to microbial pathogens. However, relatively few vesicular trafficking proteins have been implicated as regulatory components of plant immune responses. Here, a candidate-based approach was utilized to identify Arabidopsis thaliana Dynamin-Related Protein 2B (DRP2B), as a novel vesicular trafficking protein functioning in flg22-signaling and innate immunity against Pseudomonas syringae. Loss of DRP2B differently affects three distinct branches of the flg22-signaling network. My analysis was extended to investigate other DRP family members which have also been previously implicated in endocytosis. Interestingly, loss of another DRP family member results in an identical separation of immune signaling responses as described for drp2b mutant plants, providing evidence that these two DRPs may operate within a common flg22-induced signaling pathway. In addition to identifying novel components that affect flg22-induced signaling responses, work in this dissertation sought to understand the potential role(s) of flg22-induced endocytosis of FLS2 in the initiation and attenuation of flg22-induced signaling responses. To this end, I made significant contributions showing that vesicular trafficking of FLS2 is important for the desensitization of cells to flg22 via ligand-induced endocytic degradation of FLS2 and that resensitization of cells to flg22 by secretion of newly-synthesized FLS2 prepares cells for subsequent rounds of flg22-perception. Altogether, work in this dissertation provides some of the first evidence of a link between flg22-induced endocytosis of FLS2 and early flg22-signaling responses.

scholarly journals The μ Subunit of Arabidopsis Adaptor Protein-2 Is Involved in Effector-Triggered Immunity Mediated by Membrane-Localized Resistance Proteins

2016 ◽  
Vol 29 (5) ◽  
pp. 345-351 ◽  
Author(s):  
Noriyuki Hatsugai ◽  
Rachel Hillmer ◽  
Shohei Yamaoka ◽  
Ikuko Hara-Nishimura ◽  
Fumiaki Katagiri
Keyword(s):  
Plasma Membrane ◽  
Immune Responses ◽  
Pseudomonas Syringae ◽  
Adaptor Protein ◽  
Floral Organ ◽  
Coated Vesicle ◽  
Defense Gene Expression ◽  
Hypersensitive Cell Death ◽  
Cell Death Response ◽  
Effector Triggered Immunity

Endocytosis has been suggested to be important in the cellular processes of plant immune responses. However, our understanding of its role during effector-triggered immunity (ETI) is still limited. We have previously shown that plant endocytosis, especially clathrin-coated vesicle formation at the plasma membrane, is mediated by the adaptor protein-2 (AP-2) complex and that loss of the μ subunit of AP-2 (AP2M) affects plant growth and floral organ development. Here, we report that AP2M is required for full-strength ETI mediated by the disease resistance (R) genes RPM1 and RPS2 in Arabidopsis. Reduced ETI was observed in an ap2m mutant plant, measured by growth of Pseudomonas syringae pv. tomato DC3000 strains carrying the corresponding effector genes avrRpm1 or avrRpt2 and by hypersensitive cell death response and defense gene expression triggered by these strains. In contrast, RPS4-mediated ETI and its associated immune responses were not affected by the ap2m mutation. While RPM1 and RPS2 are localized to the plasma membrane, RPS4 is localized to the cytoplasm and nucleus. Our results suggest that AP2M is involved in ETI mediated by plasma membrane–localized R proteins, possibly by mediating endocytosis of the immune receptor complex components from the plasma membrane.

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