PIRIN2 stabilizes cysteine proteaseXCP2 and increases susceptibility to the vascular pathogenRalstonia solanacearumin Arabidopsis

Abstract

PIRIN (PRN) is a member of the functionally diverse cupin protein superfamily. There are four members of the Arabidopsis thaliana PRN family, but the roles of these proteins are largely unknown. Here we describe a function of the Arabidopsis PIRIN2 (PRN2) that is related to susceptibility to the bacterial plant pathogen Ralstonia solanacearum. Two prn2 mutant alleles displayed decreased disease development and bacterial growth in response to R. solanacearum infection. We elucidated the underlying molecular mechanism by analyzing PRN2 interactions with the papain-like cysteine proteases (PLCPs) XCP2, RD21A, and RD21B, all of which bound to PRN2 in yeast two-hybrid assays and in Arabidopsis protoplast co-immunoprecipitation assays. We show that XCP2 is stabilized by PRN2 through inhibition of its autolysis on the basis of PLCP activity profiling assays and enzymatic assays with recombinant protein. The stabilization of XCP2 by PRN2 was also confirmed in planta. Like prn2 mutants, an xcp2 single knockout mutant and xcp2 prn2 double knockout mutant displayed decreased susceptibility to R. solanacearum, suggesting that stabilization of XCP2 by PRN2 underlies susceptibility to R. solanacearum in Arabidopsis.

Proteome-Wide Analysis of Cysteine Reactivity during Effector-Triggered Immunity

“…Plants contain numerous proteases, and many are known to participate in immune signaling and HR initiation or execution (van der Hoorn, 2008). Barring a few exceptions (Breitenbach et al, 2014;Zhang et al, 2014), the coordination of pathogen defense pathways with the action of proteases is insufficiently understood (van der Hoorn, 2008). Several mechanisms could contribute to the impaired regulation of ETI redox homeostasis in top1top2.…”

Papain‐like cysteine proteases as hubs in plant immunity

“…Remarkably, inhibition of maize apoplastic cysteine proteases by the endogenous cystatin CC9 is essential to suppress host immunity during infection with the biotrophic pathogen U. maydis (Van der Linde et al ., ,b). Furthermore, Arabidopsis PIRIN2, a member of the cupin protein subfamily, stabilizes the protease XCP2 and increases susceptibility to the vascular pathogen R. solanacearum (Zhang et al ., ). Recently, a 9‐lipoxygenase‐derived cyclopentanone in maize, 10‐oxo‐11‐phytoenoic acid (10‐OPEA), was found to act as a potent cell death signal in multiple organs present during biotic stresses and developmental conditions (Christensen et al ., , ).…”

Transcriptome Profiling of the Green Alga Spirogyra pratensis (Charophyta) Suggests an Ancestral Role for Ethylene in Cell Wall Metabolism, Photosynthesis, and Abiotic Stress Responses

“…4, D-F). In Arabidopsis, RD21B is involved in peptidase activity during biotic and abiotic stress (Zhang et al, 2014) but does not show any ethylene responsiveness in seedlings (Winter et al, 2007;Chang et al, 2013). LEA proteins play a role during dehydration tolerance and other stress responses (Hundertmark and Hincha, 2008).…”