Functional characterization of PCRK1, a putative protein kinase with a role in immunity.

In Arabidopsis, defense signaling is triggered by the perception of conserved molecular patterns by pattern recognition receptors (PRRs). Signal transduction from the PRRs requires members of a family of Receptor-Like Cytoplasmic Kinases (RLCKs). Previously, we described one such RLCK, PTI Compromised Receptor-Like Cytoplasmic Kinase 1 (PCRK1) that is important for immunity induced by Microbe Associated Molecular Patterns (MAMPs) as well as Damage Associated Molecular Patterns (DAMPs). In this study, we measured the growth of Pma ES4326 in double mutants carrying pcrk1 together with the salicylic acid (SA) biosynthesis mutation sid2-2 or the jasmonic acid (JA) receptor mutation coi1-1, showing that the function of PCRK1 is SA independent but may be partially dependent on JA. Mutation of phosphorylated serine residues S232, S233 and S237 compromised the immune signaling function of PCRK1.