Kinase mediated regulation of plant innate immune responses
G. COAKER (1), Y. Chiang (1), M. Zhang (1), T. Toruno (1) (1) University of California, Davis, U.S.A.

Plants employ a variety of innate immune receptors that can recognize diverse pathogens. Surface localized receptors can recognize conserved microbial features and apoplastic effectors, while intracellular receptors recognize pathogen effectors delivered inside host cells. Plant immune signaling networks heavily rely on protein phosphorylation. In particular, receptor-like cytoplasmic kinases (RLCKs) have been identified as components of surface localized and intracellular receptor complexes. Here, we will present our most recent results identifying an Arabidopsis MAP kinase, SIK1, which interacts with multiple RLCKs and positively regulates RLCK stability. sik1 mutants are compromised in immunity mediated by the RPS5 immune receptor. RPS5 is an intracellular NBS-LRR immune receptor that recognizes the Pseudomonas syringae effector AvrPphB via perturbation of the PBS1 RLCK. SIK1 interacts with PBS1 and SIK1 presence enhances PBS1 stability. These data indicate that RPS5-mediated immunity is compromised in sik1 mutants due to insufficient accumulation of PBS1. SIK1 also positively regulates stability of the BIK1 RLCK and sik1 mutants exhibit altered responses to perception of bacterial flagellin. Collectively, these results indicate that SIK1 enhances the stability of multiple RLCKs to positively regulate immune responses.


Abstract Number: P7-2
Session Type: Plenary