Arabidopsis actin-binding protein WLIM2A links PAMP-triggered immunity and cytoskeletal organization

Abstract

AbstractMAPKs are a family of highly conserved serine/threonine protein kinases that link upstream receptors to their downstream targets which can be localized in the cytoplasm or the nucleus. Pathogens produce pathogen-associated molecular patterns (PAMPs) that trigger the activation of MAPK cascades in plants. Phosphoproteomic analysis of PAMP-inducedArabidopsisplants led to the identification of several putative MAPK targets, WLIM2A. Here, we investigated the role of WLIM2A in plant immunity via a reverse-genetics approach generatingwlim2aknockout lines using CRISPR-Cas9, as well as complementation and phosphosite mutatedWLIM2Aexpression lines in thewlim2abackground. Thewlim2alines were compromised in their response toPstDC3000 but showed enhanced resistance to fungal infection byBotrytis cinereae. Transcriptome analyses revealed that immune hormone signaling and biosynthesis genes of salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) are differentially regulated in thewlim2aknockout lines. Pathogen assays withPst DC3000showed altered stomatal phenotypes inwlim2amutants. Importantly,WLIM2Aphosphomutants had opposing stomatal behaviour and resistance phenotypes in response toPstDC3000 infection. Overall, these data show that phosphorylation of WLIM2A by MAPKs regulatesArabidopsisstomatal immunity.