Different roles of Enhanced Disease Susceptibility1 (EDS1) bound to and dissociated from Phytoalexin Deficient4 (PAD4) in Arabidopsis immunity

Rietz, Steffen; Stamm, Anika; Malonek, Stefan; Wagner, Stephan; Becker, D. E.; Medina‐Escobar, Nieves; Vlot, A. Corina; Feys, Bart J.; Niefind, Karsten; Parker, Jane E.

doi:10.1111/j.1469-8137.2011.03675.x

Cited by 201 publications

(236 citation statements)

References 47 publications

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“…Although the two proteins might have distinct roles in regulating plant defense and other processes (Feys et al 2005;Rietz et al 2011), evidence also suggests that they can act together in the same pathway under certain conditions (Feys et al 2005;Bartsch et al 2006;Sato et al 2007). Our data that eds1-2 and pad4-1 act nonadditively to suppress acd6-1-conferred phenotypes support the latter notion, suggesting that the two genes function in the same pathway to regulate plant defense and cell death in the acd6-1 background.…”

Section: Discussionsupporting

confidence: 75%

Genetic Dissection of Salicylic Acid-Mediated Defense Signaling Networks in Arabidopsis

Ng¹,

Seabolt²,

Zhang

et al. 2011

Genetics

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Properly coordinated defense signaling networks are critical for the fitness of plants. One hub of the defense networks is centered on salicylic acid (SA), which plays a key role in activating disease resistance in plants. However, while a number of genes are known to affect SA-mediated defense, relatively little is known about how these gene interact genetically with each other. Here we exploited the unique defense-sensitized Arabidopsis mutant accelerated cell death (acd) 6-1 to dissect functional relationships among key components in the SA hub. We show that while enhanced disease susceptibility (eds) 1-2 and phytoalexin deficient (pad) 4-1 suppressed acd6-1-conferred small size, cell death, and defense phenotypes, a combination of these two mutations did not incur additive suppression. This suggests that EDS1 and PAD4 act in the same signaling pathway. To further evaluate genetic interactions among SA regulators, we constructed 10 pairwise crosses in the acd6-1 background among mutants defective in: SA INDUCTION-DEFICIENT 2 for SA biosynthesis; AGD2-LIKE DEFENSE 1, EDS5, and PAD4 for SA accumulation; and NONEXPRESSOR OF PR GENES 1 for SA signaling. Systematic analysis of the triple mutants based on their suppression of acd6-1-conferred phenotypes revealed complex and interactive genetic relationships among the tested SA genes. Our results suggest a more comprehensive view of the gene networks governing SA function and provide a framework for further interrogation of the important roles of SA and possibly other signaling molecules in regulating plant disease resistance. IN response to pathogen infection, plants can activate different layers of defense responses and undergo global gene expression reprogramming (Maleck et al. 2000;Tao et al. 2003;Katagiri 2004). A major challenge of the postgenomic era is to identify genes that control plant innate immunity and to elucidate how they are organized into networks to orchestrate host defense responses.One key hub in plant defense signaling networks is centered on the small phenolic molecule salicylic acid (SA). SA is important for basal defense, resistance proteinmediated defense, and systemic acquired resistance (HammondKosack and Jones 1996;Ryals et al. 1996;Tsuda et al. 2008). The SA hub of Arabidopsis includes many genes, which can be further grouped into three types on the basis of how they affect SA-mediated defense (Lu 2009). Type I SA genes encode enzymes that are directly involved in SA biosynthesis. One example is SA INDUCTION-DEFICIENT 2/ENHANCED DISEASE SUSCEPTIBILITY 16 (SID2/EDS16), which encodes isochorismate synthase contributing to bulk SA biosynthesis (Wildermuth et al. 2001). Type II SA genes encode proteins that do not act directly as SA biosynthetic enzymes. Mutations in these genes lead to partially compromised SA accumulation and enhanced disease susceptibility to pathogen infection, which can be rescued by exogenous SA treatment. The precise mechanism of action for each type II SA gene, however, still remains to be resolved. Example...

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Section: Discussionsupporting

confidence: 75%

Genetic Dissection of Salicylic Acid-Mediated Defense Signaling Networks in Arabidopsis

Ng¹,

Seabolt²,

Zhang

et al. 2011

Genetics

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“…Together with the putative lipase EDS1, PAD4 is thought to be part of an amplification loop that generates increased SA levels sufficient for SA signaling and defense (Wiermer et al, 2005). Direct interactions have been detected between PAD4 and EDS1, between EDS1 and SAG101, a well-known positive regulator of senescence, and between all three proteins in a ternary complex (He and Gan, 2002;Rietz et al, 2011;Zhu et al, 2011). It has been shown that PAD4 and EDS1 participate not only in resistance to pathogens but also in the transduction of photooxidative stress signals resulting in cell death and growth inhibition.…”

Section: Discussionmentioning

confidence: 99%

Early Senescence and Cell Death in Arabidopsis saul1 Mutants Involves the PAD4-Dependent Salicylic Acid Pathway

Vogelmann

Drechsel²,

Bergler³

et al. 2012

Plant Physiology

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Age-dependent leaf senescence and cell death in Arabidopsis (Arabidopsis thaliana) requires activation of the transcription factor ORESARA1 (ORE1) and is not initiated prior to a leaf age of 28 d. Here, we investigate the conditional execution of events that regulate early senescence and cell death in senescence-associated ubiquitin ligase1 (saul1) mutants, deficient in the PLANT U-BOX-ARMADILLO E3 ubiquitin ligase SAUL1. In saul1 mutants challenged with low light, the switch of age-dependent cell death was turned on prematurely, as indicated by the accumulation of ORE1 transcripts, induction of the senescence marker gene SENESCENCE-ASSOCIATED GENE12, and cell death. However, ORE1 accumulation by itself was not sufficient to cause saul1 phenotypes, as demonstrated by double mutant analysis. Exposure of saul1 mutants to low light for only 24 h did not result in visible symptoms of senescence; however, the senescence-promoting transcription factor genes WRKY53, WRKY6, and NAC-LIKE ACTIVATED BY AP3/PI were up-regulated, indicating that senescence in saul1 seedlings was already initiated. To resolve the time course of gene expression, microarray experiments were performed at narrow intervals. Differential expression of the genes involved in salicylic acid and defense mechanisms were the earliest events detected, suggesting a central role for salicylic acid in saul1 senescence and cell death. The salicylic acid content increased in low-light-treated saul1 mutants, and application of exogenous salicylic acid was indeed sufficient to trigger saul1 senescence in permissive light conditions. Double mutant analyses showed that PHYTOALEXIN DEFICIENT4 (PAD4) but not NONEXPRESSER OF PR GENES1 (NPR1) is essential for saul1 phenotypes. Our results indicate that saul1 senescence depends on the PAD4-dependent salicylic acid pathway but does not require NPR1 signaling.

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“…2 G and H). RBA1-mediated cell death also was dependent on PAD4, which is part of the EDS1 signaling complex (29), and was partially dependent on SID2, but was independent of RAR1, a cochaperone protein required for some, but not all, NLRbased disease-resistance responses (Fig. 2H) (30).…”

Section: Rba1 Is Autoactive and Enhanced Disease Susceptibility 1-depmentioning

confidence: 99%

TIR-only protein RBA1 recognizes a pathogen effector to regulate cell death in Arabidopsis

Nishimura

Anderson

Cherkis

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

132

119

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Detection of pathogens by plants is mediated by intracellular nucleotide-binding site leucine-rich repeat (NLR) receptor proteins. NLR proteins are defined by their stereotypical multidomain structure: an N-terminal Toll-interleukin receptor (TIR) or coiled-coil (CC) domain, a central nucleotide-binding (NB) domain, and a C-terminal leucine-rich repeat (LRR). The plant innate immune system contains a limited NLR repertoire that functions to recognize all potential pathogens. We isolated Response to the bacterial type III effector protein HopBA1 (RBA1), a gene that encodes a TIR-only protein lacking all other canonical NLR domains. RBA1 is sufficient to trigger cell death in response to HopBA1. We generated a crystal structure for HopBA1 and found that it has similarity to a class of proteins that includes esterases, the hemebinding protein ChaN, and an uncharacterized domain of Pasteurella multocida toxin. Self-association, coimmunoprecipitation with HopBA1, and function of RBA1 require two previously identified TIR-TIR dimerization interfaces. Although previously described as distinct in other TIR proteins, in RBA1 neither of these interfaces is sufficient when the other is disrupted. These data suggest that oligomerization of RBA1 is required for function. Our identification of RBA1 demonstrates that "truncated" NLRs can function as pathogen sensors, expanding our understanding of both receptor architecture and the mechanism of activation in the plant immune system. plant immunity | NLR | Toll-interleukin-1 receptor homology domain | oligomerization | type III secretion

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Different roles of Enhanced Disease Susceptibility1 (EDS1) bound to and dissociated from Phytoalexin Deficient4 (PAD4) in Arabidopsis immunity

Cited by 201 publications

References 47 publications

Genetic Dissection of Salicylic Acid-Mediated Defense Signaling Networks in Arabidopsis

Genetic Dissection of Salicylic Acid-Mediated Defense Signaling Networks in Arabidopsis

Early Senescence and Cell Death in Arabidopsis saul1 Mutants Involves the PAD4-Dependent Salicylic Acid Pathway

TIR-only protein RBA1 recognizes a pathogen effector to regulate cell death in Arabidopsis

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