CALCIUM-DEPENDENT PROTEIN KINASE5 Associates with the Truncated NLR Protein TIR-NBS2 to Contribute to exo70B1-Mediated Immunity

Abstract

Calcium-dependent protein kinases (CPKs) function as calcium sensors and play important roles in plant immunity. Loss of function of the exocyst complex subunit EXO70B1 leads to autoimmunity caused by activation of TN2, a truncated Toll/interleukin-1 receptor-nucleotide binding sequence protein. Here we show, based on a screen for suppressors of , that-activated autoimmune responses require However, the CPK5 homologs CPK4, CPK6, and CPK11, which were previously reported to function redundantly with CPK5 in effector-triggered immunity, did not contribute to-associated phenotypes, indicating that CPK5 plays a unique role in plant immunity. Overexpressing results in TN2-dependent autoimmunity and enhanced disease resistance, reminiscent of the phenotypes. Ectopic expression of in the mutant led to constitutive CPK5 protein kinase activity, which was not detectable in mutants. Furthermore, TN2 interacts with the CPK5 N-terminal variable and kinase domains, stabilizing CPK5 kinase activity in vitro. This work uncovers a direct functional link between an atypical immune receptor and a crucial component of early immune signaling: increased immunity in depends on TN2 and CPK5 and, in a positive feedback loop, TN2 keeps CPK5 enzymatically active beyond the initiating stimulus.

Next‐generation sequencing identified genomic region and diagnostic markers for resistance to bacterial wilt on chromosome B02 in peanut (Arachis hypogaea L.)

“…Recent reports showed that the repression of auxin pathway improved the resistance to bacterial pathogen (French et al, 2018;Navarro, 2016). The gene Araip.CMC8E might code for calcium-dependent protein kinase, which could perceive changes in intracellular calcium concentrations to transmit defence signal in response to PAMPs and pathogen effectors (Liu et al, 2017;Wang et al, 2018a). The gene Araip.CZ54N was predicted to encode for serine/threonineprotein phosphatase, which was reported to be involved in hypersensitive response (Zhou et al, 1995).…”

Properties and functions of calcium‐dependent protein kinases and their relatives inArabidopsis thaliana

“…To maintain membrane association, proteins undergo reversible palmitoylation on a close cysteine or harbor a basic domain in the VNTD (Chehab et al ., ) which can be counteracted by phosphorylation. The reversibility of this process allows proteins to shuttle between cytoplasm and membranes, as observed for AtCPK10/30/32 that translocate to the nucleus in response to nitrate (Liu et al ., 2017a). Palmitoylation has also been observed in vitro for AtCPK16 (Stael et al ., ) and in vivo for AtCRK2 and nine CPKs (Hemsley et al ., ).…”

Prioritization of abiotic and biotic plant stress responses through ABI1 phosphatase and CPK5 calcium-dependent protein kinase switch

“…In stable transgenic A. thaliana plants expressing CPK5-YFP the co-expression of ABI1-1mcherry results in a stronger effect than ABI1-11-mcherry ( Fig. S5A) and leads to tiny plants and lethality for the ABI1-1 variant, reminiscent to a constitutive 'enhanced SAR' phenotype (9) and auto-immunity (10). This finding suggests an over-induced immune response caused by already activated CPK5-signaling plus an additional synergistic factor through phosphatase ABI1-1.…”