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 Pseudomonas syringae pv. tomato DC3000 Effector HopG1 is a multi-faceted protein that Triggers Necrotic Cell Death that is attenuated by the Nonhost Resistance 2B (AtNHR2B) Protein

2021 ◽  
Author(s):  
Catalina Rodriguez-Puerto ◽  
Rupak Chakraborty ◽  
Raksha Singh ◽  
Perla Rocha-Loyola ◽  
Clemencia M. Rojas
Keyword(s):  
Cell Death ◽  
Plant Defense ◽  
Pseudomonas Syringae ◽  
Plant Immunity ◽  
Defense Responses ◽  
Necrotic Cell Death ◽  
Plant Defense Responses ◽  
Necrotic Cell ◽  
Tomato Dc3000 ◽  
Type Iii

The plant pathogenic bacterium Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) has become a paradigm in plant-bacteria interactions due to its ability to cause disease in the model plant Arabidopsis thaliana. Pst DC3000 uses the type III secretion system to deliver type III secreted effectors (T3SEs) directly into the plant cytoplasm. Pst DC3000 T3SEs contribute to pathogenicity by suppressing plant defense responses and targeting plant’s physiological processes. Although the complete repertoire of effectors encoded in the Pst DC3000 genome have been identified, the specific function for most of them remains to be elucidated. The mitochondrial-localized T3E HopG1, suppresses plant defense responses and promotes the development of disease symptoms. Here, we show that HopG1 triggers necrotic cell death that enables the growth of non-adapted pathogens. We further showed that HopG1 interacts with the plant immunity-related protein AtNHR2B and that AtNHR2B attenuates HopG1- virulence functions.

scholarly journals Tomato wall-associated kinase SlWak1 acts in an Fls2- and Fls3-dependent manner to promote apoplastic immune responses to Pseudomonas syringae

2020 ◽  
Author(s):  
Ning Zhang ◽  
Marina A Pombo ◽  
Hernan G Rosli ◽  
Gregory B Martin
Keyword(s):  
Gene Expression ◽  
Immune Responses ◽  
Pseudomonas Syringae ◽  
Molecular Mechanisms ◽  
Plant Immunity ◽  
Transcript Abundance ◽  
Dependent Manner ◽  
Wild Type ◽  
Disease Symptoms

Wall-associated kinases (Waks) are known to be important components of plant immunity against various pathogens including Pseudomonas syringae pv. tomato (Pst) although their molecular mechanisms are largely unknown. In tomato, SlWak1 has been implicated in immunity because its transcript abundance increases significantly in leaves after treatment with the flagellin-derived peptides flg22 and flgII-28, which activate the receptors Fls2 and Fls3, respectively. We generated two SlWak1 tomato mutants (Δwak1) using CRISPR/Cas9 and investigated the role of SlWak1 in tomato-Pst interactions. PTI activated in the apoplast by flg22 or flgII-28 was compromised in Δwak1 plants but PTI at the leaf surface was unaffected. The Δwak1 plants developed fewer callose deposits than wild-type plants but retained the ability to generate reactive oxygen species and activate MAPKs in response to flg22 and flgII-28. The induction of Wak1 gene expression by flg22 and flgII-28 was greatly reduced in a tomato mutant lacking Fls2 and Fls3 but induction of Fls3 gene expression by flgII-28 was unaffected in Δwak1 plants. After Pst inoculation, Δwak1 plants developed disease symptoms more slowly than Δfls2.1/fls2.2/fls3 mutant plants, although both plants ultimately were similarly susceptible. SlWak1 co-immunoprecipitated with both Fls2 and Fls3 independently of flg22/flgII-28 or Bak1. These observations suggest that SlWak1 acts in a complex with Fls2/Fls3 and plays an important role at later stages of the PTI in the apoplast.

scholarly journals Uncoupling Salicylic Acid-Dependent Cell Death and Defense-Related Responses From Disease Resistance in the Arabidopsis Mutant acd5

Genetics ◽  
2000 ◽  
Vol 156 (1) ◽  
pp. 341-350
Author(s):  
Jean T Greenberg ◽  
F Paul Silverman ◽  
Hua Liang
Keyword(s):  
Cell Death ◽  
Salicylic Acid ◽  
Disease Resistance ◽  
Pseudomonas Syringae ◽  
Higher Plants ◽  
Ethylene Signaling ◽  
Symptom Development ◽  
Wild Type ◽  
Dependent Cell ◽  
Arabidopsis Mutant

Abstract Salicylic acid (SA) is required for resistance to many diseases in higher plants. SA-dependent cell death and defense-related responses have been correlated with disease resistance. The accelerated cell death 5 mutant of Arabidopsis provides additional genetic evidence that SA regulates cell death and defense-related responses. However, in acd5, these events are uncoupled from disease resistance. acd5 plants are more susceptible to Pseudomonas syringae early in development and show spontaneous SA accumulation, cell death, and defense-related markers later in development. In acd5 plants, cell death and defense-related responses are SA dependent but they do not confer disease resistance. Double mutants with acd5 and nonexpressor of PR1, in which SA signaling is partially blocked, show greatly attenuated cell death, indicating a role for NPR1 in controlling cell death. The hormone ethylene potentiates the effects of SA and is important for disease symptom development in Arabidopsis. Double mutants of acd5 and ethylene insensitive 2, in which ethylene signaling is blocked, show decreased cell death, supporting a role for ethylene in cell death control. We propose that acd5 plants mimic P. syringae-infected wild-type plants and that both SA and ethylene are normally involved in regulating cell death during some susceptible pathogen infections.

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.

The Leucine-Rich Repeat Domain Can Determine Effective Interaction Between RPS2 and Other Host Factors in Arabidopsis RPS2-Mediated Disease Resistance

Genetics ◽  
2001 ◽  
Vol 158 (1) ◽  
pp. 439-450 ◽  
Author(s):  
Diya Banerjee ◽  
Xiaochun Zhang ◽  
Andrew F Bent
Keyword(s):  
Disease Resistance ◽  
Pseudomonas Syringae ◽  
Plant Disease Resistance ◽  
Effective Interaction ◽  
Molecular Genetic ◽  
Defense Responses ◽  
Host Factors ◽  
Leucine Rich Repeat ◽  
Domain Swap ◽  
Allele Specific

Abstract Like many other plant disease resistance genes, Arabidopsis thaliana RPS2 encodes a product with nucleotide-binding site (NBS) and leucine-rich repeat (LRR) domains. This study explored the hypothesized interaction of RPS2 with other host factors that may be required for perception of Pseudomonas syringae pathogens that express avrRpt2 and/or for the subsequent induction of plant defense responses. Crosses between Arabidopsis ecotypes Col-0 (resistant) and Po-1 (susceptible) revealed segregation of more than one gene that controls resistance to P. syringae that express avrRpt2. Many F2 and F3 progeny exhibited intermediate resistance phenotypes. In addition to RPS2, at least one additional genetic interval associated with this defense response was identified and mapped using quantitative genetic methods. Further genetic and molecular genetic complementation experiments with cloned RPS2 alleles revealed that the Po-1 allele of RPS2 can function in a Col-0 genetic background, but not in a Po-1 background. The other resistance-determining genes of Po-1 can function, however, as they successfully conferred resistance in combination with the Col-0 allele of RPS2. Domain-swap experiments revealed that in RPS2, a polymorphism at six amino acids in the LRR region is responsible for this allele-specific ability to function with other host factors.

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 Overexpression of Pto Induces a Salicylate-Independent Cell Death But Inhibits Necrotic Lesions Caused by Salicylate-Deficiency in Tomato Plants

2002 ◽  
Vol 15 (7) ◽  
pp. 654-661 ◽  
Author(s):  
Jianxiong Li ◽  
Libo Shan ◽  
Jian-Min Zhou ◽  
Xiaoyan Tang
Keyword(s):  
Cell Death ◽  
Disease Resistance ◽  
Pseudomonas Syringae ◽  
Virulent Strain ◽  
Gene Activation ◽  
Cellular Damage ◽  
Minor Role ◽  
Disease Resistance Gene ◽  
Tomato Plants ◽  
Spontaneous Cell Death

Tomato plants overexpressing the disease resistance gene Pto (35S∷Pto) exhibit spontaneous cell death, accumulation of salicylic acid (SA), elevated expression of pathogenesis-related genes, and enhanced resistance to a broad range of pathogens. Because salicylate plays an important role in the cell death and defense activation in many lesion mimic mutants, we investigated the interaction of SA-mediated processes and the 35S∷Pto-mediated defense pathway by introducing the nahG transgene that encodes salicylate hydroxylase. Here, we show that SA is not required for the 35S∷Pto-activated microscopic cell death and plays a minor role in defense gene activation and general disease resistance in 35S∷Pto plants. In contrast, temperature greatly affects the spontaneous cell death and general resistance in 35S∷Pto plants, and high temperature inhibits the cell death. The NahG tomato plants develop spontaneous, unconstrained necrotic lesions on leaves. These lesions also are initiated by the inoculation of a virulent strain of Pseudomonas syringae pv. tomato. However, the NahG-dependent necrotic lesions are inhibited in the NahG/35S∷Pto plants. This inhibition is most pronounced under conditions favoring the 35S∷Pto-mediated spontaneous cell death development. These results indicate that the signaling pathways activated by Pto overexpression suppress the cellular damage that is caused by SA depletion. We also found that ethylene is dispensable for the 35S∷Pto-mediated general defense.

scholarly journals A20: a master regulator of arthritis

2020 ◽  
Vol 22 (1) ◽  
Author(s):  
Yongyao Wu ◽  
Xiaomin He ◽  
Ning Huang ◽  
Jiayun Yu ◽  
Bin Shao
Keyword(s):  
Cell Death ◽  
Immune Responses ◽  
Mouse Models ◽  
Inflammatory Arthritis ◽  
Molecular Mechanisms ◽  
Related Research ◽  
Inflammatory Protein ◽  
New Findings ◽  
Tnf Α

Abstract A20, also known as TNF-α-induced protein 3 (TNFAIP3), is an anti-inflammatory protein that plays an important part in both immune responses and cell death. Impaired A20 function is associated with several human inflammatory and autoimmune diseases. Although the role of A20 in mediating inflammation has been frequently discussed, its intrinsic link to arthritis awaits further explanation. Here, we review new findings that further demonstrate the molecular mechanisms through which A20 regulates inflammatory arthritis, and we discuss the regulation of A20 by many factors. We conclude by reviewing the latest A20-associated mouse models that have been applied in related research because they reflect the characteristics of arthritis, the study of which will hopefully cast new light on anti-arthritis treatments.

scholarly journals Update on Cuticular Wax Biosynthesis and Its Roles in Plant Disease Resistance

2020 ◽  
Vol 21 (15) ◽  
pp. 5514
Author(s):  
Xiaoyu Wang ◽  
Lingyao Kong ◽  
Pengfei Zhi ◽  
Cheng Chang
Keyword(s):  
Disease Resistance ◽  
Plant Disease Resistance ◽  
Plant Disease ◽  
Molecular Mechanisms ◽  
Higher Plants ◽  
Defense Responses ◽  
Cuticular Wax ◽  
Cuticular Waxes ◽  
Infection Processes ◽  
Plant Pathogen Interactions

The aerial surface of higher plants is covered by a hydrophobic layer of cuticular waxes to protect plant tissues against enormous environmental challenges including the infection of various pathogens. As the first contact site between plants and pathogens, the layer of cuticular waxes could function as a plant physical barrier that limits the entry of pathogens, acts as a reservoir of signals to trigger plant defense responses, and even gives cues exploited by pathogens to initiate their infection processes. Past decades have seen unprecedented proceedings in understanding the molecular mechanisms underlying the biosynthesis of plant cuticular waxes and their functions regulating plant–pathogen interactions. In this review, we summarized the recent progress in the molecular biology of cuticular wax biosynthesis and highlighted its multiple roles in plant disease resistance against bacterial, fungal, and insect pathogens.

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