ORCID Profile
0000-0002-3535-6053
Current Organisation
Universiteit Leiden Instituut Biologie Leiden
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Publisher: Public Library of Science (PLoS)
Date: 05-05-2017
Publisher: Cold Spring Harbor Laboratory
Date: 28-07-2021
DOI: 10.1101/2021.07.28.454147
Abstract: Plants use intracellular immune receptors (NLRs) to detect pathogen-derived effector proteins. The Arabidopsis NLR pair RRS1-R/RPS4 confers disease resistance to different bacterial pathogens by perceiving structurally distinct effectors AvrRps4 from Pseudomonas syringae pv . pisi and PopP2 from Ralstonia solanacearum via an integrated WRKY domain in RRS1-R. How the WRKY domain of RRS1 (RRS1 WRKY ) perceives distinct classes of effector to initiate an immune response is unknown. We report here the crystal structure of the in planta processed C-terminal domain of AvrRps4 (AvrRps4 C ) in complex with RRS1 WRKY . Perception of AvrRps4 C by RRS1 WRKY is mediated by the β2-β3 segment of RRS1 WRKY that binds an electronegative patch on the surface of AvrRps4 C . Structure-based mutations that disrupt AvrRps4 C /RRS1 WRKY interactions in vitro compromise RRS1/RPS4-dependent immune responses. We also show that AvrRps4 C can associate with the WRKY domain of the related but distinct RRS1B/RPS4B NLR pair, and the DNA binding domain of At WRKY41, with similar binding affinities. This work demonstrates how integrated domains in plant NLRs can directly bind structurally distinct effectors to initiate immunity. This study reveals a mechanism of effector recognition by a plant NLR immune receptor that carries an integrated domain (ID) which mimics an authentic pathogen effector target. An Arabidopsis immune receptor carrying RRS1 and RPS4 NLR proteins detects the Pseudomonas syringae pv . pisi secreted effector AvrRps4 via a WRKY ID in RRS1. We used structural biology to reveal the mechanisms of AvrRps4/WRKY interaction and demonstrated that this binding is essential for effector recognition in planta. Our analysis revealed distinctive features of the WRKY ID that mediate the recognition of structurally distinct effectors from different bacterial pathogens. These insights could enable engineering NLRs with novel recognition specificities, and enhances our understanding of how effectors interact with host proteins.
Publisher: Oxford University Press (OUP)
Date: 19-02-2013
Abstract: In fungi and metazoans, extracellular signals are often perceived by G-protein-coupled receptors (GPCRs) and transduced through heterotrimeric G-protein complexes to downstream targets. Plant heterotrimeric G proteins are also involved in erse biological processes, but little is known about their upstream receptors. Moreover, the presence of bona fide GPCRs in plants is yet to be established. In Arabidopsis (Arabidopsis thaliana), heterotrimeric G protein consists of one Gα subunit (G PROTEIN α-SUBUNIT1), one Gβ subunit (ARABIDOPSIS G PROTEIN β-SUBUNIT1 [AGB1]), and three Gγs subunits (ARABIDOPSIS G PROTEIN γ-SUBUNIT1 [AGG1], AGG2, and AGG3). We identified AGB1 from a suppressor screen of BAK1-interacting receptor-like kinase1-1 (bir1-1), a mutant that activates cell death and defense responses mediated by the receptor-like kinase (RLK) SUPPRESSOR OF BIR1-1. Mutations in AGB1 suppress the cell death and defense responses in bir1-1 and transgenic plants overexpressing SUPPRESSOR OF BIR1-1. In addition, agb1 mutant plants were severely compromised in immunity mediated by three other RLKs, FLAGELLIN-SENSITIVE2 (FLS2), Elongation Factor-TU RECEPTOR (EFR), and CHITIN ELICITOR RECEPTOR KINASE1 (CERK1), respectively. By contrast, G PROTEIN α-SUBUNIT1 is not required for either cell death in bir1-1 or pathogen-associated molecular pattern-triggered immunity mediated by FLS2, EFR, and CERK1. Further analysis of agg1 and agg2 mutant plants indicates that AGG1 and AGG2 are also required for pathogen-associated molecular pattern-triggered immune responses mediated by FLS2, EFR, and CERK1, as well as cell death and defense responses in bir1-1. We hypothesize that the Arabidopsis heterotrimeric G proteins function as a converging point of plant defense signaling by mediating responses initiated by multiple RLKs, which may fulfill equivalent roles to GPCRs in fungi and animals.
Publisher: Proceedings of the National Academy of Sciences
Date: 24-07-2020
Abstract: Animal NLRs form wheel-like structures called inflammasomes upon perception of pathogen-associated molecules. The induced proximity of the signaling domains at the center of the wheel is hypothesized to recruit caspases for the first step of immune signal transduction. We expressed a plant-animal NLR fusion to demonstrate that induced proximity of TIR signaling domains from plant NLRs is sufficient to activate plant immune signaling. This demonstrates that a signaling-competent inflammasome can be formed from known, minimal components. The intrinsic NADase activity of plant TIRs is necessary for immune signaling, but fusions to a bacterial or a mammalian TIR domain with NADase activity, which also lead to accumulation of NAD + hydrolysis products (e.g. cyclic ADP-ribose), were unable to activate immune signaling.
Publisher: Proceedings of the National Academy of Sciences
Date: 08-12-2021
Abstract: This study reveals a mechanism for effector perception by a plant NLR immune receptor that contains an integrated domain (ID) that mimics an authentic effector target. The Arabidopsis immune receptors RRS1 and RPS4 detect the Pseudomonas syringae pv. pisi secreted effector AvrRps4 via a WRKY ID in RRS1. We used structural biology to reveal the mechanisms of AvrRps4 C –WRKY interaction and demonstrated that this binding is essential for effector recognition in planta. Our analysis revealed features of the WRKY ID that mediate perception of structurally distinct effectors from different bacterial pathogens. These insights could enable engineering NLRs with novel recognition specificities, and enhance our understanding of how effectors interact with host proteins to promote virulence.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Pingtao Ding.