RECEPTOR–LIKE CYTOPLASMIC KINASE FACILITATES PLANT IMMUNITY VIA INTERACTION AND PHOSPHORYLATION WITH EFFECTOR-TARGETED PROTEIN RIN4 IN ARABIDOPSIS
E. CHUNG (1), R. Anderson (2), J. Dangl (3) (1) Howard Hughes Medical Institute (HHMI) / UNC-Chapel Hill, U.S.A.; (2) Department of Biology, UNC-Chapel Hill, U.S.A.; (3) Howard Hughes Medical Institute (HHMI), UNC-Chapel Hill, U.S.A.

RIN4 is a small plasma membrane tethered plant protein contributing to Microbe-Associated Molecular Patterns (MAMPs)-triggered immunity (MTI) outputs via induced phosphorylation on Ser141. RIN4 is targeted by at least four different bacterial type III effectors. Two of these effector proteins, AvrB and AvrRpm1, induce RIN4 phosphorylation on Thr166 residue via RPM1-induced protein kinase (RIPK) to repress MTI responses by decreasing RIN4 S141 phosphorylation. Induced RIN4 pThr166 can be recognized by the nucleotide-binding domain and leucine-rich repeat (NLR) family of intracellular immune receptor Resistance to Pseudomonas maculicola 1 (RPM1). RIPK belongs to a family of Receptor-like Cytoplasmic Kinases (RLCK) VII including botrytis-induced kinase 1 (BIK1) and PBS1-like 1 (PBL1). BIK1 and PBL1 are involved in activation of Flagellin sensing 2 (FLS2) by the flagellin peptide flg22. Therefore, we investigated role of BIK1 and PBL1 in MTI in terms of RIN4 phosphorylation. Here we show that BIK1 interacts with RIN4 in vitro and in planta and can phosphorylate RIN4 Ser141 contributing to full MTI response. In addition, we identified several other RIN4-interacting kinases in the receptor–like cytoplasmic kinases (RLCK) IIV family. Thus, we propose these RLCK IIV kinases manipulate RIN4 to modulate plant immunity.

Abstract Number: P17-509
Session Type: Poster