scholarly journals Effector Triggered Immunity: NLR Immune Perception and Downstream Defense Responses

2015 ◽  
Vol 13 ◽  
pp. e0183 ◽  
Author(s):  
Yi-Hsuan Chiang ◽  
Gitta Coaker
Keyword(s):  
Defense Responses ◽  
Effector Triggered Immunity

scholarly journals The Effect of Transcription Factor MYB14 on Defense Mechanisms in Vitis quinquangularis-Pingyi

2020 ◽  
Vol 21 (3) ◽  
pp. 706 ◽  
Author(s):  
Yangyang Luo ◽  
Qingyang Wang ◽  
Ru Bai ◽  
Ruixiang Li ◽  
Lu Chen ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Nicotiana Benthamiana ◽  
Defense Mechanisms ◽  
Qualitative Difference ◽  
Defense Responses ◽  
Molecular Pattern ◽  
Effector Triggered Immunity ◽  
Pathogen Associated Molecular Pattern ◽  
Basal Immunity ◽  
Stilbene Biosynthesis

In the current study, we identified a transcription factor, MYB14, from Chinese wild grape, Vitis quinquangularis-Pingyi (V. quinquangularis-PY), which could enhance the main stilbene contents and expression of stilbene biosynthesis genes (StSy/RS) by overexpression of VqMYB14. The promoter of VqMYB14 (pVqMYB14) was shown to be induced as part of both basal immunity (also called pathogen-associated molecular pattern (PAMP)-triggered immunity, PTI) and effector-triggered immunity (ETI), triggered by the elicitors flg22 and harpin, respectively. This was demonstrated by expression of pVqMYB14 in Nicotiana benthamiana and Vitis. We identified sequence differences, notably an 11 bp segment in pVqMYB14 that is important for the PTI/ETI, and particularly for the harpin-induced ETI response. In addition, we showed that activation of the MYB14 promoter correlates with differences in the expression of MYB14 and stilbene pattern induced by flg22 and harpin. An experimental model of upstream signaling in V. quinquangularis-PY is presented, where early defense responses triggered by flg22 and harpin partially overlap, but where the timing and levels differ. This translates into a qualitative difference with respect to patterns of stilbene accumulation.

scholarly journals Functional Analysis of Plant Defense Suppression and Activation by the Xanthomonas Core Type III Effector XopX

2015 ◽  
Vol 28 (2) ◽  
pp. 180-194 ◽  
Author(s):  
William Stork ◽  
Jung-Gun Kim ◽  
Mary Beth Mudgett
Keyword(s):  
Plant Defense ◽  
Defense Responses ◽  
Effector Proteins ◽  
Immune Signaling ◽  
Type Iii ◽  
Effector Triggered Immunity ◽  
Gene Transcripts ◽  
Type Iii Secretion Effector ◽  
Susceptible Tomato

Many phytopathogenic type III secretion effector proteins (T3Es) have been shown to target and suppress plant immune signaling but perturbation of the plant immune system by T3Es can also elicit a plant response. XopX is a “core” Xanthomonas T3E that contributes to growth and symptom development during Xanthomonas euvesicatoria infection of tomato but its functional role is undefined. We tested the effect of XopX on several aspects of plant immune signaling. XopX promoted ethylene production and plant cell death (PCD) during X. euvesicatoria infection of susceptible tomato and in transient expression assays in Nicotiana benthamiana, which is consistent with its requirement for the development of X. euvesicatoria-induced disease symptoms. Additionally, although XopX suppressed flagellin-induced reactive oxygen species, it promoted the accumulation of pattern-triggered immunity (PTI) gene transcripts. Surprisingly, XopX coexpression with other PCD elicitors resulted in delayed PCD, suggesting antagonism between XopX-dependent PCD and other PCD pathways. However, we found no evidence that XopX contributed to the suppression of effector-triggered immunity during X. euvesicatoria–tomato interactions, suggesting that XopX's primary virulence role is to modulate PTI. These results highlight the dual role of a core Xanthomonas T3E in simultaneously suppressing and activating plant defense responses.

scholarly journals The PTI to ETI Continuum in Phytophthora-Plant Interactions

2020 ◽  
Vol 11 ◽  
Author(s):  
Zunaira Afzal Naveed ◽  
Xiangying Wei ◽  
Jianjun Chen ◽  
Hira Mubeen ◽  
Gul Shad Ali
Keyword(s):  
Host Defense ◽  
Induced Defense ◽  
Plant Immunity ◽  
Defense Responses ◽  
Mapk Signaling ◽  
Cell Trafficking ◽  
Plant Interactions ◽  
Physiological Processes ◽  
Effector Triggered Immunity ◽  
Induced Defense Responses

Phytophthora species are notorious pathogens of several economically important crop plants. Several general elicitors, commonly referred to as Pathogen-Associated Molecular Patterns (PAMPs), from Phytophthora spp. have been identified that are recognized by the plant receptors to trigger induced defense responses in a process termed PAMP-triggered Immunity (PTI). Adapted Phytophthora pathogens have evolved multiple strategies to evade PTI. They can either modify or suppress their elicitors to avoid recognition by host and modulate host defense responses by deploying hundreds of effectors, which suppress host defense and physiological processes by modulating components involved in calcium and MAPK signaling, alternative splicing, RNA interference, vesicle trafficking, cell-to-cell trafficking, proteolysis and phytohormone signaling pathways. In incompatible interactions, resistant host plants perceive effector-induced modulations through resistance proteins and activate downstream components of defense responses in a quicker and more robust manner called effector-triggered-immunity (ETI). When pathogens overcome PTI—usually through effectors in the absence of R proteins—effectors-triggered susceptibility (ETS) ensues. Qualitatively, many of the downstream defense responses overlap between PTI and ETI. In general, these multiple phases of Phytophthora-plant interactions follow the PTI-ETS-ETI paradigm, initially proposed in the zigzag model of plant immunity. However, based on several examples, in Phytophthora-plant interactions, boundaries between these phases are not distinct but are rather blended pointing to a PTI-ETI continuum.

scholarly journals Sustained Incompatibility between MAPK Signaling and Pathogen Effectors

2020 ◽  
Vol 21 (21) ◽  
pp. 7954
Author(s):  
Julien Lang ◽  
Jean Colcombet
Keyword(s):  
Defense Responses ◽  
Mapk Signaling ◽  
Effector Proteins ◽  
Plant Defense Responses ◽  
Pathogen Effectors ◽  
Current State ◽  
Pathogen Effector ◽  
Mitogen Activated Protein ◽  
Effector Triggered Immunity ◽  
Signaling Components

In plants, Mitogen-Activated Protein Kinases (MAPKs) are important signaling components involved in developemental processes as well as in responses to biotic and abiotic stresses. In this review, we focus on the roles of MAPKs in Effector-Triggered Immunity (ETI), a specific layer of plant defense responses dependent on the recognition of pathogen effector proteins. Having inspected the literature, we synthesize the current state of knowledge concerning this topic. First, we describe how pathogen effectors can manipulate MAPK signaling to promote virulence, and how in parallel plants have developed mechanisms to protect themselves against these interferences. Then, we discuss the striking finding that the recognition of pathogen effectors can provoke a sustained activation of the MAPKs MPK3/6, extensively analyzing its implications in terms of regulation and functions. In line with this, we also address the question of how a durable activation of MAPKs might affect the scope of their substrates, and thereby mediate the emergence of possibly new ETI-specific responses. By highlighting the sometimes conflicting or missing data, our intention is to spur further research in order to both consolidate and expand our understanding of MAPK signaling in immunity.

scholarly journals Signaling Pathways and Downstream Effectors of Host Innate Immunity in Plants

2021 ◽  
Vol 22 (16) ◽  
pp. 9022
Author(s):  
Jitendra Kumar ◽  
Ayyagari Ramlal ◽  
Kamal Kumar ◽  
Anita Rani ◽  
Vachaspati Mishra
Keyword(s):  
Innate Immunity ◽  
Host Plants ◽  
Defense Responses ◽  
R Genes ◽  
Molecular Processes ◽  
Receptor Proteins ◽  
Downstream Effectors ◽  
Effector Triggered Immunity ◽  
Current Article ◽  
Molecular Patterns

Phytopathogens, such as biotrophs, hemibiotrophs and necrotrophs, pose serious stress on the development of their host plants, compromising their yields. Plants are in constant interaction with such phytopathogens and hence are vulnerable to their attack. In order to counter these attacks, plants need to develop immunity against them. Consequently, plants have developed strategies of recognizing and countering pathogenesis through pattern-triggered immunity (PTI) and effector-triggered immunity (ETI). Pathogen perception and surveillance is mediated through receptor proteins that trigger signal transduction, initiated in the cytoplasm or at the plasma membrane (PM) surfaces. Plant hosts possess microbe-associated molecular patterns (P/MAMPs), which trigger a complex set of mechanisms through the pattern recognition receptors (PRRs) and resistance (R) genes. These interactions lead to the stimulation of cytoplasmic kinases by many phosphorylating proteins that may also be transcription factors. Furthermore, phytohormones, such as salicylic acid, jasmonic acid and ethylene, are also effective in triggering defense responses. Closure of stomata, limiting the transfer of nutrients through apoplast and symplastic movements, production of antimicrobial compounds, programmed cell death (PCD) are some of the primary defense-related mechanisms. The current article highlights the molecular processes involved in plant innate immunity (PII) and discusses the most recent and plausible scientific interventions that could be useful in augmenting PII.

scholarly journals Comparative transcriptomic profiling of susceptible and resistant cultivars of pigeonpea demonstrates early molecular responses during Fusarium udum infection

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Arnab Purohit ◽  
Sanatan Ghosh ◽  
Shreeparna Ganguly ◽  
Madan Singh Negi ◽  
Shashi Bhushan Tripathi ◽  
...  
Keyword(s):  
Early Stage ◽  
Defense Responses ◽  
Homology Search ◽  
Transcriptomic Profiling ◽  
Regulatory Pathways ◽  
Fusarium Udum ◽  
Invasion Stage ◽  
Effector Triggered Immunity ◽  
Root Tissues ◽  
Important Disease

AbstractVascular wilt caused by Fusarium udum Butler is the most important disease of pigeonpea throughout the world. F. udum isolate MTCC 2204 (M1) inoculated pigeonpea plants of susceptible (ICP 2376) and resistant (ICP 8863) cultivars were taken at invasion stage of pathogenesis process for transcriptomic profiling to understand defense signaling reactions that interplay at early stage of this plant–pathogen encounter. Differential transcriptomic profiles were generated through cDNA-AFLP from M1 inoculated resistant and susceptible pigeonpea root tissues. Twenty five percent of transcript derived fragments (TDFs) were found to be pathogen induced. Among them 73 TDFs were re-amplified and sequenced. Homology search of the TDFs in available databases and thorough study of scientific literature identified several pathways, which could play crucial role in defense responses of the F. udum inoculated resistant plants. Some of the defense responsive pathways identified to be active during this interaction are, jasmonic acid and salicylic acid mediated defense responses, cell wall remodeling, vascular development and pattering, abscisic acid mediated responses, effector triggered immunity, and reactive oxygen species mediated signaling. This study identified important wilt responsive regulatory pathways in pigeonpea which will be helpful for further exploration of these resistant components for pigeonpea improvement.

scholarly journals Defense Responses of Nicotiana benthamiana 14‐3‐3 Genes in Virus‐Induced Effector‐Triggered Immunity

2015 ◽  
Vol 29 (S1) ◽  
Author(s):  
Jennifer Spencer ◽  
Soha Sobhanian ◽  
Melanie Sacco
Keyword(s):  
Nicotiana Benthamiana ◽  
Defense Responses ◽  
Effector Triggered Immunity

scholarly journals Conserved Opposite Functions in Plant Resistance to Biotrophic and Necrotrophic Pathogens of the Immune Regulator SRFR1

2021 ◽  
Vol 22 (12) ◽  
pp. 6427
Author(s):  
Geon-Hui Son ◽  
Jiyun Moon ◽  
Rahul Mahadev Shelake ◽  
Uyen Thi Vuong ◽  
Robert A. Ingle ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Plant Immunity ◽  
Defense Responses ◽  
Negative Regulator ◽  
Heterodera Schachtii ◽  
Pathogen Effector ◽  
Effector Triggered Immunity ◽  
Biotrophic Pathogens ◽  
Resistance Protein ◽  
Sugar Beet Cyst Nematode

Plant immunity is mediated in large part by specific interactions between a host resistance protein and a pathogen effector protein, named effector-triggered immunity (ETI). ETI needs to be tightly controlled both positively and negatively to enable normal plant growth because constitutively activated defense responses are detrimental to the host. In previous work, we reported that mutations in SUPPRESSOR OF rps4-RLD1 (SRFR1), identified in a suppressor screen, reactivated EDS1-dependent ETI to Pseudomonas syringae pv. tomato (Pto) DC3000. Besides, mutations in SRFR1 boosted defense responses to the generalist chewing insect Spodoptera exigua and the sugar beet cyst nematode Heterodera schachtii. Here, we show that mutations in SRFR1 enhance susceptibility to the fungal necrotrophs Fusarium oxysporum f. sp. lycopersici (FOL) and Botrytis cinerea in Arabidopsis. To translate knowledge obtained in AtSRFR1 research to crops, we generated SlSRFR1 alleles in tomato using a CRISPR/Cas9 system. Interestingly, slsrfr1 mutants increased expression of SA-pathway defense genes and enhanced resistance to Pto DC3000. In contrast, slsrfr1 mutants elevated susceptibility to FOL. Together, these data suggest that SRFR1 is functionally conserved in both Arabidopsis and tomato and functions antagonistically as a negative regulator to (hemi-) biotrophic pathogens and a positive regulator to necrotrophic pathogens.

scholarly journals Nuclear Localization of HopA1Pss61 Is Required for Effector-Triggered Immunity

Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 888
Author(s):  
Hobin Kang ◽  
Quang-Minh Nguyen ◽  
Arya Bagus Boedi Iswanto ◽  
Jong Chan Hong ◽  
Saikat Bhattacharjee ◽  
...  
Keyword(s):  
Cell Death ◽  
Pseudomonas Syringae ◽  
Nuclear Localization ◽  
Functional Characterization ◽  
Defense Responses ◽  
Disease Resistance Gene ◽  
In Planta ◽  
Resistance Proteins ◽  
Cell Death Response ◽  
Effector Triggered Immunity

Plant resistance proteins recognize cognate pathogen avirulence proteins (also named effectors) to implement the innate immune responses called effector-triggered immunity. Previously, we reported that hopA1 from Pseudomonas syringae pv. syringae strain 61 was identified as an avr gene for Arabidopsis thaliana. Using a forward genetic screen approach, we cloned a hopA1-specific TIR-NBS-LRR class disease resistance gene, RESISTANCE TO PSEUDOMONAS SYRINGAE6 (RPS6). Many resistance proteins indirectly recognize effectors, and RPS6 is thought to interact with HopA1Pss61 indirectly by surveillance of an effector target. However, the involved target protein is currently unknown. Here, we show RPS6 is the only R protein that recognizes HopA1Pss61 in Arabidopsis wild-type Col-0 accession. Both RPS6 and HopA1Pss61 are co-localized to the nucleus and cytoplasm. HopA1Pss61 is also distributed in plasma membrane and plasmodesmata. Interestingly, nuclear localization of HopA1Pss61 is required to induce cell death as NES-HopA1Pss61 suppresses the level of cell death in Nicotiana benthamiana. In addition, in planta expression of hopA1Pss61 led to defense responses, such as a dwarf morphology, a cell death response, inhibition of bacterial growth, and increased accumulation of defense marker proteins in transgenic Arabidopsis. Functional characterization of HopA1Pss61 and RPS6 will provide an important piece of the ETI puzzle.

DEFENSE RESPONSES DURING THE LEGUME—Rhizobium SYMBIOSIS: INDUCTION AND SUPPRESSION (review)

2014 ◽  
pp. 3-12
Author(s):  
K.A. Ivanova ◽  
◽  
V.E. Tsyganov ◽  
Keyword(s):  
Defense Responses
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