9-methyl sphingoid base generated by cleavage of pathogen-derived ceramide is recognized by a lectin receptor-like kinase in Arabidopsis thaliana

We introduced Lumi-Map, a platform of large-scale identification of plant PTI-related genes by a combined use of an automated bioluminescence monitoring and MutMap, a whole genome sequencing-based method for identification of causative SNPs in the mutant. Using Lumi-Map, we identified two novel genes required for immunity in Arabidopsis thaliana. We show that a ceramide PiCerD derived from an oomycete pathogen Phytophthora infestans triggers defense response in Arabidopsis. PiCerD is cleaved by Arabidopsis apoplastic ceramidase PiCD and the resulting 9-methyl branched sphingoid base is recognized by a plasmamembrane lectin receptor-like kinase PiCR of Arabidopsis. Loss of function of PiCR and PiCD compromised Arabidopsis resistance against oomycete pathogen, indicating their crucial roles in the defense. These results provide new insights into understanding the recognition mechanisms of pathogen-derived lipid molecules in plant.