Perception of the pathogen?induced peptide RGF7 by the receptor?like kinases RGI4 and RGI5 triggers innate immunity in <i>Arabidopsis thaliana</i>

Signaling peptides play crucial roles in plant growth, development and defense. We report here that the Arabidopsis thaliana secreted peptide, ROOT MERISTEM GROWTH FACTOR 7 (RGF7), functions as an endogenous elicitor to trigger immunity. Expression of RGF7 precursor-encoding gene (preRGF7) is highly induced leaves upon infection by bacterial pathogen Pseudomonas syringae. The pathogen-responsive preRGF7 expression regulated transcription factor WRKY33 its upstream mitogen-activated protein kinases MPK3/MPK6 calcium-dependent CPK5/CPK6. In absence attack, chemically transgenic plants was sufficient immune responses. Pre-induction also led enhanced responses increased resistance P. syringae infection. Biochemical genetic analyses demonstrated perceived leaf-expressed RGF1 INSENSITIVE (RGI) family receptors RGI4 RGI5. SOMATIC EMBRYOGENESIS RECEPTOR KINASES (SERKs) BAK1 SERK4 are involved perception via forming RGF7-induced receptor-complexes with These results indicate pathogen-induced RGI4/RGI5-BAK1/SERK4 receptor complexes, acts a new damage-associated molecular pattern (DAMP) plays significant role