scholarly journals Broad-Spectrum Disease Resistance Conferred by the Overexpression of Rice RLCK BSR1 Results from an Enhanced Immune Response to Multiple MAMPs

2019 ◽  
Vol 20 (22) ◽  
pp. 5523 ◽  
Author(s):  
Yasukazu Kanda ◽  
Hitoshi Nakagawa ◽  
Yoko Nishizawa ◽  
Takashi Kamakura ◽  
Masaki Mori
Keyword(s):  
Disease Resistance ◽  
Immune Responses ◽  
Broad Spectrum ◽  
Transcriptional Activation ◽  
Intracellular Signaling ◽  
Cultured Cells ◽  
Plant Immunity ◽  
Production Of Hydrogen ◽  
Defense Related Gene ◽  
Molecular Patterns

Plants activate their immune system through intracellular signaling pathways after perceiving microbe-associated molecular patterns (MAMPs). Receptor-like cytoplasmic kinases mediate the intracellular signaling downstream of pattern-recognition receptors. BROAD-SPECTRUM RESISTANCE 1 (BSR1), a rice (Oryza sativa) receptor-like cytoplasmic kinase subfamily-VII protein, contributes to chitin-triggered immune responses. It is valuable for agriculture because its overexpression confers strong disease resistance to fungal and bacterial pathogens. However, it remains unclear how overexpressed BSR1 reinforces plant immunity. Here we analyzed immune responses using rice suspension-cultured cells and sliced leaf blades overexpressing BSR1. BSR1 overexpression enhances MAMP-triggered production of hydrogen peroxide (H2O2) and transcriptional activation of the defense-related gene in cultured cells and leaf strips. Furthermore, the co-cultivation of leaves with conidia of the blast fungus revealed that BSR1 overexpression allowed host plants to produce detectable oxidative bursts against compatible pathogens. BSR1 was also involved in the immune responses triggered by peptidoglycan and lipopolysaccharide. Thus, we concluded that the hyperactivation of MAMP-triggered immune responses confers BSR1-mediated robust resistance to broad-spectrum pathogens.

scholarly journals Overexpressed BSR1-Mediated Enhancement of Disease Resistance Depends on the MAMP-Recognition System

2020 ◽  
Vol 21 (15) ◽  
pp. 5397
Author(s):  
Yasukazu Kanda ◽  
Yoko Nishizawa ◽  
Takashi Kamakura ◽  
Masaki Mori
Keyword(s):  
Disease Resistance ◽  
Immune Responses ◽  
Broad Spectrum ◽  
Blast Resistance ◽  
Plant Immunity ◽  
Recognition System ◽  
Wild Type ◽  
Broad Spectrum Resistance ◽  
Molecular Patterns ◽  
Plant Plasma Membrane

Plant plasma membrane-localized receptors recognize microbe-associated molecular patterns (MAMPs) and activate immune responses via various signaling pathways. Receptor-like cytoplasmic kinases (RLCKs) are considered key signaling factors in plant immunity. BROAD-SPECTRUM RESISTANCE 1 (BSR1), a rice RLCK, plays a significant role in disease resistance. Overexpression of BSR1 confers strong resistance against fungal and bacterial pathogens. Our recent study revealed that MAMP-triggered immune responses are mediated by BSR1 in wild-type rice and are hyperactivated in BSR1-overexpressing rice. It was suggested that hyperactivated immune responses were responsible for the enhancement of broad-spectrum disease resistance; however, this remained to be experimentally validated. In this study, we verified the above hypothesis by disrupting the MAMP-recognition system in BSR1-overexpressing rice. To this end, we knocked out OsCERK1, which encodes a well-characterized MAMP-receptor-like protein kinase. In the background of BSR1 overaccumulation, the knockout of OsCERK1 nearly abolished the enhancement of blast resistance. This finding indicates that overexpressed BSR1-mediated enhancement of disease resistance depends on the MAMP-triggered immune system, corroborating our previously suggested model.

scholarly journals YODA MAP3K kinase regulates plant immune responses conferring broad-spectrum disease resistance

2018 ◽  
Vol 218 (2) ◽  
pp. 661-680 ◽  
Author(s):  
Sara Sopeña-Torres ◽  
Lucía Jordá ◽  
Clara Sánchez-Rodríguez ◽  
Eva Miedes ◽  
Viviana Escudero ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Immune Responses ◽  
Broad Spectrum

scholarly journals Divergent Evolution of PcF/SCR74 Effectors in Oomycetes Is Associated with Distinct Recognition Patterns in Solanaceous Plants

mBio ◽  
2020 ◽  
Vol 11 (3) ◽  
Author(s):  
Xiao Lin ◽  
Shumei Wang ◽  
Laura de Rond ◽  
Nicoletta Bertolin ◽  
Roland H. M. Wouters ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Cell Surface ◽  
Immune Responses ◽  
Arms Race ◽  
Wild Potato ◽  
Content Type ◽  
Surface Receptors ◽  
Molecular Patterns ◽  
Solanaceous Plants ◽  
Coevolutionary Arms Race

ABSTRACT Plants deploy cell surface receptors known as pattern-recognition receptors (PRRs) that recognize non-self molecules from pathogens and microbes to defend against invaders. PRRs typically recognize microbe-associated molecular patterns (MAMPs) that are usually widely conserved, some even across kingdoms. Here, we report an oomycete-specific family of small secreted cysteine-rich (SCR) proteins that displays divergent patterns of sequence variation in the Irish potato famine pathogen Phytophthora infestans. A subclass that includes the conserved effector PcF from Phytophthora cactorum activates immunity in a wide range of plant species. In contrast, the more diverse SCR74 subclass is specific to P. infestans and tends to trigger immune responses only in a limited number of wild potato genotypes. The SCR74 response was recently mapped to a G-type lectin receptor kinase (G-LecRK) locus in the wild potato Solanum microdontum subsp. gigantophyllum. The G-LecRK locus displays a high diversity in Solanum host species compared to other solanaceous plants. We propose that the diversification of the SCR74 proteins in P. infestans is driven by a fast coevolutionary arms race with cell surface immune receptors in wild potato, which contrasts the presumed slower dynamics between conserved apoplastic effectors and PRRs. Understanding the molecular determinants of plant immune responses to these divergent molecular patterns in oomycetes is expected to contribute to deploying multiple layers of disease resistance in crop plants. IMPORTANCE Immune receptors at the plant cell surface can recognize invading microbes. The perceived microbial molecules are typically widely conserved and therefore the matching surface receptors can detect a broad spectrum of pathogens. Here we describe a family of Phytophthora small extracellular proteins that consists of conserved subfamilies that are widely recognized by solanaceous plants. Remarkably, one subclass of SCR74 proteins is highly diverse, restricted to the late blight pathogen Phytophthora infestans and is specifically detected in wild potato plants. The diversification of this subfamily exhibits signatures of a coevolutionary arms race with surface receptors in potato. Insights into the molecular interaction between these potato-specific receptors and the recognized Phytophthora proteins are expected to contribute to disease resistance breeding in potato.

scholarly journals Phosphatase PP2C6 negatively regulates phosphorylation status of Pti1b kinase, a regulator of flagellin-triggered immunity in tomato

2019 ◽  
Author(s):  
Fabian Giska ◽  
Gregory B. Martin
Keyword(s):  
Immune Responses ◽  
Plant Immunity ◽  
Active Form ◽  
Control Plant ◽  
Negative Regulator ◽  
Response To Treatment ◽  
Positive Regulators ◽  
Molecular Patterns

AbstractPlant immune responses, including the production of reactive oxygen species (ROS), are triggered when pattern recognition receptors (PRR) become activated upon detection of microbe-associated molecular patterns (MAMPs). Receptor-like cytoplasmic kinases are key components of PRR-dependent signaling pathways. In tomato two such kinases, Pti1a and Pti1b, are important positive regulators of the plant immune response. However, it is unknown how these kinases control plant immunity at the molecular level, and how their activity is regulated. To investigate these issues, we used mass spectrometry to search for interactors of Pti1b in Nicotiana benthamiana leaves and identified a protein phosphatase, PP2C6. An in vitro pull-down assay and in vivo split luciferase complementation assay verified this interaction. Pti1b was found to autophosphorylate on threonine-233 and this phosphorylation was abolished in the presence of PP2C6. An arginine-to-cysteine substitution at position 240 in the Arabidopsis MARIS kinase was previously reported to convert it into a constitutive-active form. The analogous substitution in Pti1b made it resistant to PP2C6 phosphatase activity, although it still interacted with PP2C6. Treatment of N. benthamiana leaves with the MAMP flg22 induced threonine phosphorylation of Pti1b. Expression of PP2C6, but not a phosphatase-inactive variant of this protein, in N. benthamiana leaves greatly reduced ROS production in response to treatment with MAMPs flg22 or csp22. The results indicate that PP2C6 acts as a negative regulator by dephosphorylating the Pti1b kinase, thereby interfering with its ability to activate plant immune responses.

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 PP2C phosphatase Pic1 negatively regulates the phosphorylation status of Pti1b kinase, a regulator of flagellin-triggered immunity in tomato

2019 ◽  
Vol 476 (11) ◽  
pp. 1621-1635 ◽  
Author(s):  
Fabian Giska ◽  
Gregory B. Martin
Keyword(s):  
Immune Responses ◽  
Plant Immunity ◽  
Active Form ◽  
Control Plant ◽  
Negative Regulator ◽  
Response To Treatment ◽  
Positive Regulators ◽  
Molecular Patterns

Abstract Plant immune responses, including the production of reactive oxygen species (ROS), are triggered when pattern recognition receptors (PRRs) become activated upon detection of microbe-associated molecular patterns (MAMPs). Receptor-like cytoplasmic kinases are key components of PRR-dependent signaling pathways. In tomato, two such kinases, Pti1a and Pti1b, are important positive regulators of the plant immune response. However, it is unknown how these kinases control plant immunity at the molecular level and how their activity is regulated. To investigate these issues, we used mass spectrometry to search for interactors of Pti1b in Nicotiana benthamiana leaves and identified a PP2C protein phosphatase, referred to as Pic1. An in vitro pull-down assay and in vivo split-luciferase complementation assay verified this interaction. Pti1b was found to autophosphorylate on threonine-233, and this phosphorylation was abolished in the presence of Pic1. An arginine-to-cysteine substitution at position 240 in the Arabidopsis MARIS kinase was previously reported to convert it into a constitutive-active form. The analogous substitution in Pti1b made it resistant to Pic1 phosphatase activity, although it still interacted with Pic1. Treatment of N. benthamiana leaves with the MAMP flg22 induced threonine phosphorylation of Pti1b. The expression of Pic1, but not a phosphatase-inactive variant of this protein, in N. benthamiana leaves greatly reduced ROS production in response to treatment with MAMPs flg22 or csp22. The results indicate that Pic1 acts as a negative regulator by dephosphorylating the Pti1b kinase, thereby interfering with its ability to activate plant immune responses.

scholarly journals Molecular characterization of HEXOKINASE1 in plant innate immunity

2020 ◽  
Vol 63 (1) ◽  
Author(s):  
Wu Jing ◽  
Shahab Uddin ◽  
Rupak Chakraborty ◽  
Duong Thu Van Anh ◽  
Donah Mary Macoy ◽  
...  
Keyword(s):  
Immune Responses ◽  
Pseudomonas Syringae ◽  
Glucose Sensor ◽  
Plant Immunity ◽  
Interacting Protein ◽  
Bacterial Populations ◽  
Effector Triggered Immunity ◽  
Callose Formation ◽  
Molecular Patterns

AbstractHexokinase1 (HXK1) is an Arabidopsis glucose sensor that has a variety of roles during plant growth and devlopment, including during germination, flowering, and senescence. HXK1 also acts as a positive regulator of plant immune responses. Previous research suggested that HXK1 might influence plant immune responses via responses to glucose. Plant immune responses are governed by two main pathways: PAMP-triggered immunity (PTI) and effector-triggered immunity (ETI). PTI involves the recognition of Pathogen-Associated Molecular Patterns (PAMPs) and leads to increased callose formation and accumulation of pathogenesis response (PR) proteins. ETI acts in response to effectors secreted by Gram-negative bacteria. During ETI, the membrane-localized protein RPM1-interacting protein 4 (RIN4) becomes phosphorylated in reponse to interactions with effectors and mediates the downstream response. In this study, the effects of glucose on plant immune responses against infection with Pseudomonas syringae pv. tomato DC3000 and other P. syringae strains were investigated in the presence and absence of HXK1. Infiltration of leaves with glucose prior to infection led to decreases in bacterial populations and reductions in disease symptoms in wild-type Arabidopsis plants, indicating that glucose plays a role in plant immunity. Both PTI and ETI responses were affected. However, these effects were not observed in a hxk1 mutant, indicating that the effects of glucose on plant immune responses were mediated by HXK1-related pathways.

scholarly journals Understanding and Exploiting Post-Translational Modifications for Plant Disease Resistance

Biomolecules ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1122
Author(s):  
Catherine Gough ◽  
Ari Sadanandom
Keyword(s):  
Disease Resistance ◽  
Immune Responses ◽  
Plant Disease Resistance ◽  
Plant Immunity ◽  
Dynamic Responses ◽  
Post Translational Modifications ◽  
Pathogen Effectors ◽  
Trade Offs ◽  
Defence Signalling ◽  
Fine Tune

Plants are constantly threatened by pathogens, so have evolved complex defence signalling networks to overcome pathogen attacks. Post-translational modifications (PTMs) are fundamental to plant immunity, allowing rapid and dynamic responses at the appropriate time. PTM regulation is essential; pathogen effectors often disrupt PTMs in an attempt to evade immune responses. Here, we cover the mechanisms of disease resistance to pathogens, and how growth is balanced with defence, with a focus on the essential roles of PTMs. Alteration of defence-related PTMs has the potential to fine-tune molecular interactions to produce disease-resistant crops, without trade-offs in growth and fitness.

scholarly journals The N-terminus of an Ustilaginoidea virens Ser-Thr-rich glycosylphosphatidylinositol-anchored protein elicits plant immunity as a MAMP

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Tianqiao Song ◽  
You Zhang ◽  
Qi Zhang ◽  
Xiong Zhang ◽  
Danyu Shen ◽  
...  
Keyword(s):  
Immune Responses ◽  
Plant Immunity ◽  
Phosphatidyl Inositol ◽  
Defense Responses ◽  
Ustilaginoidea Virens ◽  
Amino Acid Peptide ◽  
N Terminus ◽  
Defense Related Gene ◽  
Rice Panicles

AbstractMany pathogens infect hosts through specific organs, such as Ustilaginoidea virens, which infects rice panicles. Here, we show that a microbe-associated molecular pattern (MAMP), Ser-Thr-rich Glycosyl-phosphatidyl-inositol-anchored protein (SGP1) from U. virens, induces immune responses in rice leaves but not panicles. SGP1 is widely distributed among fungi and acts as a proteinaceous, thermostable elicitor of BAK1-dependent defense responses in N. benthamiana. Plants specifically recognize a 22 amino acid peptide (SGP1 N terminus peptide 22, SNP22) in its N-terminus that induces cell death, oxidative burst, and defense-related gene expression. Exposure to SNP22 enhances rice immunity signaling and resistance to infection by multiple fungal and bacterial pathogens. Interestingly, while SGP1 can activate immune responses in leaves, SGP1 is required for U. virens infection of rice panicles in vivo, showing it contributes to the virulence of a panicle adapted pathogen.

scholarly journals A NAC Transcription Factor TuNAC69 Contributes to ANK-NLR-WRKY NLR-Mediated Stripe Rust Resistance in the Diploid Wheat Triticum urartu

2022 ◽  
Vol 23 (1) ◽  
pp. 564
Author(s):  
Yang Xu ◽  
Shenghao Zou ◽  
Hao Zeng ◽  
Wei Wang ◽  
Bin Wang ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Stripe Rust ◽  
Transcriptional Activation ◽  
Puccinia Striiformis ◽  
Plant Immunity ◽  
Rust Fungus ◽  
Diploid Wheat ◽  
Stripe Rust Resistance ◽  
Virus Induced Gene Silencing ◽  
Triticum Urartu

Stripe rust is one of the most devastating diseases in wheat. Nucleotide-binding site (NBS) and leucine-rich repeat (LRR) domain receptors (NLRs) recognize pathogenic effectors and trigger plant immunity. We previously identified a unique NLR protein YrU1 in the diploid wheat Triticum urartu, which contains an N-terminal ANK domain and a C-terminal WRKY domain and confers disease resistance to stripe rust fungus Puccinia striiformis f. sp. Tritici (Pst). However, how YrU1 functions in disease resistance is not clear. In this study, through the RNA-seq analysis, we found that the expression of a NAC member TuNAC69 was significantly up-regulated after inoculation with Pst in the presence of YrU1. TuNAC69 was mainly localized in the nucleus and showed transcriptional activation in yeast. Knockdown TuNAC69 in diploid wheat Triticum urartu PI428309 that contains YrU1 by virus-induced gene silencing reduced the resistance to stripe rust. In addition, overexpression of TuNAC69 in Arabidopsis enhanced the resistance to powdery mildew Golovinomyces cichoracearum. In summary, our study indicates that TuNAC69 participates in the immune response mediated by NLR protein YrU1, and likely plays an important role in disease resistance to other pathogens.

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