Plasmopara viticola effector PvRXLR111 stabilizes VvWRKY40 to promote virulence

Abstract

Plasmopara viticola, the causal organism of grapevine downy mildew, secretes a vast array of effectors to manipulate host immunity. Previously, several cell death‐inducing PvRXLR effectors have been identified, but their functions and host targets are poorly understood. Here, we investigated the role of PvRXLR111, a cell death‐inducing RXLR effector, in manipulating plant immunity. When coexpressed with other PvRXLR effectors, PvRXLR111‐induced cell death was prevented. Transient expression of PvRXLR111 in Nicotiana benthamiana suppressed bacterial flagellin peptide flg22‐elicited immune responses and enhanced Phytophthora capsici infection. PvRXLR111 induction in Arabidopsis increased susceptibility to Hyaloperonospora arabidopsidis. PvRXLR111 expression in Pseudomonas syringae promoted bacterial colonization. By immunoprecipitation‐mass spectrometry analysis, yeast two‐hybrid, pull‐down, and bimolecular fluorescence complementation assays, it was shown that PvRXLR111 interacted with Vitis vinifera putative WRKY transcription factor 40 (VvWRKY40), which increased VvWRKY40 stability. Transient expression of VvWRKY40 in N. benthamiana inhibited flg22‐induced reactive oxygen species burst and enhanced P. capsici infection and silencing NbWRKY40 attenuated P. capsici colonization. These results suggest VvWRKY40 functions as a negative regulator in plant immunity and that PvRXLR111 suppresses host immunity by stabilizing VvWRKY40.

The secreted ribonuclease T2 protein FoRnt2 contributes to Fusarium oxysporum virulence

“…PsCRN108, a P. sojae CRN effector, enhances susceptibility to P. capsici , while the expression of the gene in N. benthamiana and A. thaliana down‐regulates defence‐related gene expression (Song et al, 2015 ). Transient expression of PvRXLR11, which is an effector of Plasmopara viticola , in N. benthamiana enhances P. capsici infection, indicating that PvRXLR11 can suppress host defence responses by stabilizing VvWRKY40 (Ma et al, 2021 ). RXLR25, a virulence factor and effector of P. capsici , inhibits the phosphorylation of target proteins of host plants to suppress immunity and promote Phytophthora pathogen infection of host plants (Liang et al, 2021 ).…”

Pathogen Adaptation to American (Rpv3-1) and Eurasian (Rpv29) Grapevine Loci Conferring Resistance to Downy Mildew

“…Almost all the adapted strains were not very aggressive, as testified by the reduced growth on the reference cultivar PN, and therefore they could possess fitness penalties compared to non-adapted strains within the pathogen population in the field. The studies on the effector array of P. viticola during the interaction with vinifera and non- vinifera species are under constant evolution [ 25 , 32 , 33 , 34 ]. It would be interesting in the future to identify the effectors expressed by these two strains.…”

Valsa mali secretes an effector protein VmEP1 to target a K homology domain‐containing protein for virulence in apple

“…Cell death was quantified by determining electrolyte leakage using a previously described method (Ma et al, 2021 ; Nayyar & Chander, 2004 ). Samples from N. benthamiana (diameter 1 cm) expressing MdKRBP4 were immersed in nanopure water (5 ml) for 3 h at room temperature to determine the electrical conductivity (E 1 ).…”

“…Typically, to counteract the plant immune system and establish a successful infection during colonization, pathogenic microorganisms deploy effectors to avoid host recognition and inhibit the host defence response (Pradhan et al, 2021 ). These effector molecules manipulate the immune response by targeting key host proteins, such as lectin‐like receptor kinase protein (Kanzaki et al, 2008 ), E3 ubiquitin ligase (Bos et al, 2010 ; Park et al, 2012 ), BAK1‐associated receptor complexes (Lu et al, 2010 ), protein kinase (Murphy et al, 2018 ; Tanaka et al, 2014 ), exocyst component Sec5 (Du et al, 2015 ), peroxidase (Hemetsberger et al, 2012 ; Zhang et al, 2015 ), protein phosphatase 1 (Boevink et al, 2016 ), endoplasmic reticulum (ER)‐luminal binding immunoglobulin proteins (Jing et al, 2016 ), cytoplasmic transacetylase (Li et al, 2018 ), and WRKY transcription factors (Ma et al, 2021 ), which regulate diverse aspects of plant cell development and metabolism. However, pathogen effectors rarely target KH domain‐containing proteins.…”