P-055 - MIK2-family receptors from different plant lineages show overlapping and distinct recognition specificity for exogenous and endogenous signalling peptides

Fusarium spp. cause severe plant diseases exemplified by Fusarium Head Blight of cereal crops or Panama Disease of banana. Microbe-associated molecular patterns (MAMPs) can be perceived by plants activating pattern-triggered immunity (PTI). Knowledge of MAMPs or corresponding plant immunity components is largely lacking for Fusarium spp.. We identified a peptide elicitor fraction in Fusarium and related fungi that elicits PTI. We evidenced the causal mutation in an elicitor-insensitive Arabidopsis mutant in a leucine-rich receptor-like kinase gene (MIK2). We now widened MIK2 functions to the perception of comparable elicitors from a broader spectrum of Sordariomycetes. Genetic interaction of MIK2 with PTI signalling components and new data on receptor-elicitor-interaction further establish MIK2 as a probable pattern-recognition receptor. Because MIK2 also functions as a receptor for endogenous SCOOP peptides that act as immune-stimulating phytocytokines in Brassicaceae, we studied MIK2-family receptors from tomato,  a plant species that does not encode SCOOP peptides. Together with recent literature, we suggest an unique function in phytocytokine signaling in Brassicaceae but cross-plant family conserved MIK2 function in PTI. Hence, MIK2 receptor kinases likely evolved as pattern recognition receptors and subfunctionalized, specifically in Brassicaceae, for SCOOP peptide recognition.