Separable Fragments and Membrane Tethering of <i>Arabidopsis</i> RIN4 Regulate Its Suppression of PAMP-Triggered Immunity

Afzal, Ahmed J.; Cunha, Luis da; Mackey, David

doi:10.1105/tpc.111.088708

Cited by 60 publications

(83 citation statements)

References 55 publications

(94 reference statements)

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“…On the one hand, RIPK could signal through RIN4/RPM1 -independent signalling cascades yet to be identified. On the other hand, genetic redundancy in the RIN4 and RIN4-like proteins might blur our analyses [50]. Further experimental evidence will be needed to establish the recruitment of the RIN4/RPM1 signalling module in xopAC -triggered immunity.…”

Section: Discussionmentioning

confidence: 99%

xopAC-triggered Immunity against Xanthomonas Depends on Arabidopsis Receptor-Like Cytoplasmic Kinase Genes PBL2 and RIPK

et al. 2013

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Xanthomonas campestris pv. campestris (Xcc) colonizes the vascular system of Brassicaceae and ultimately causes black rot. In susceptible Arabidopsis plants, XopAC type III effector inhibits by uridylylation positive regulators of the PAMP-triggered immunity such as the receptor-like cytoplasmic kinases (RLCK) BIK1 and PBL1. In the resistant ecotype Col-0, xopAC is a major avirulence gene of Xcc. In this study, we show that both the RLCK interaction domain and the uridylyl transferase domain of XopAC are required for avirulence. Furthermore, xopAC can also confer avirulence to both the vascular pathogen Ralstonia solanacearum and the mesophyll-colonizing pathogen Pseudomonas syringae indicating that xopAC-specified effector-triggered immunity is not specific to the vascular system. In planta, XopAC-YFP fusions are localized at the plasma membrane suggesting that XopAC might interact with membrane-localized proteins. Eight RLCK of subfamily VII predicted to be localized at the plasma membrane and interacting with XopAC in yeast two-hybrid assays have been isolated. Within this subfamily, PBL2 and RIPK RLCK genes but not BIK1 are important for xopAC-specified effector-triggered immunity and Arabidopsis resistance to Xcc.

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Section: Discussionmentioning

confidence: 99%

xopAC-triggered Immunity against Xanthomonas Depends on Arabidopsis Receptor-Like Cytoplasmic Kinase Genes PBL2 and RIPK

et al. 2013

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“…At first glance, the cleavage of a PTI suppressor such as RIN4 by AvrRpt2 does not appear to be favorable for the pathogen. However, RIN4 cleavage products were shown to be even more active PTI suppressors than the uncleaved protein (Afzal, da Cunha and Mackey 2011). RIN4 is presumably not the only target of AvrRpt2 because predicted AvrRpt2 cleavage sites are also present in other plant proteins.…”

Section: Effector Proteins and Plant Defense Responsesmentioning

confidence: 99%

Behind the lines–actions of bacterial type III effector proteins in plant cells

Büttner¹

2016

FEMS Microbiology Reviews

227

233

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Pathogenicity of most Gram-negative plant-pathogenic bacteria depends on the type III secretion (T3S) system, which translocates bacterial effector proteins into plant cells. Type III effectors modulate plant cellular pathways to the benefit of the pathogen and promote bacterial multiplication. One major virulence function of type III effectors is the suppression of plant innate immunity, which is triggered upon recognition of pathogen-derived molecular patterns by plant receptor proteins. Type III effectors also interfere with additional plant cellular processes including proteasome-dependent protein degradation, phytohormone signaling, the formation of the cytoskeleton, vesicle transport and gene expression. This review summarizes our current knowledge on the molecular functions of type III effector proteins with known plant target molecules. Furthermore, plant defense strategies for the detection of effector protein activities or effector-triggered alterations in plant targets are discussed.

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“…Suppression of MPK4/MPK11 activation was observed only if AvrRpt2 was expressed. Finally, to address the role of proper RIN4 cellular localization, a non-membrane-tethering mutant (RIN4 C203A/C204A/ C205A; Kim et al, 2005a;Afzal et al, 2011) was overexpressed. This also did not abrogate the MPK4/MPK11 inactivation phenotype (Fig.…”

Section: The Suppression Of Mpk4 and Mpk11 Activation Is Independent mentioning

confidence: 99%

Bacterial AvrRpt2-Like Cysteine Proteases Block Activation of the Arabidopsis Mitogen-Activated Protein Kinases, MPK4 and MPK11

et al. 2016

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To establish infection, pathogens deliver effectors into host cells to target immune signaling components, including elements of mitogen-activated protein kinase (MPK) cascades. The virulence function of AvrRpt2, one of the first identified Pseudomonas syringae effectors, involves cleavage of the plant defense regulator, RPM1-INTERACTING PROTEIN4 (RIN4), and interference with plant auxin signaling. We show now that AvrRpt2 specifically suppresses the flagellin-induced phosphorylation of Arabidopsis (Arabidopsis thaliana) MPK4 and MPK11 but not MPK3 or MPK6. This inhibition requires the proteolytic activity of AvrRpt2, is associated with reduced expression of some plant defense genes, and correlates with enhanced pathogen infection in AvrRpt2-expressing transgenic plants. Diverse AvrRpt2-like homologs can be found in some phytopathogens, plant-associated and soil bacteria. Employing these putative bacterial AvrRpt2 homologs and inactive AvrRpt2 variants, we can uncouple the inhibition of MPK4/MPK11 activation from the cleavage of RIN4 and related members from the so-called nitrate-induced family as well as from auxin signaling. Thus, this selective suppression of specific mitogen-activated protein kinases is independent of the previously known AvrRpt2 targets and potentially represents a novel virulence function of AvrRpt2.

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Separable Fragments and Membrane Tethering of Arabidopsis RIN4 Regulate Its Suppression of PAMP-Triggered Immunity

Cited by 60 publications

References 55 publications

xopAC-triggered Immunity against Xanthomonas Depends on Arabidopsis Receptor-Like Cytoplasmic Kinase Genes PBL2 and RIPK

xopAC-triggered Immunity against Xanthomonas Depends on Arabidopsis Receptor-Like Cytoplasmic Kinase Genes PBL2 and RIPK

Behind the lines–actions of bacterial type III effector proteins in plant cells

Bacterial AvrRpt2-Like Cysteine Proteases Block Activation of the Arabidopsis Mitogen-Activated Protein Kinases, MPK4 and MPK11

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