Recognition of pathogen-derived sphingolipids in .

In plants, many invading microbial pathogens are recognized by cell-surface pattern recognition receptors, which induce defense responses. Here, we show that the ceramide -ceramide D (Pi-Cer D) from the plant pathogenic oomycete triggers defense responses in . Pi-Cer D is cleaved by an apoplastic ceramidase, NEUTRAL CERAMIDASE 2 (NCER2), and the resulting 9-methyl-branched sphingoid base is recognized by a plasma membrane lectin receptor-like kinase, RESISTANT TO DFPM-INHIBITION OF ABSCISIC ACID SIGNALING 2 (RDA2). 9-Methyl-branched sphingoid base is specific to microbes and induces plant immune responses by physically interacting with RDA2. Loss of or function compromised resistance against an oomycete pathogen. Thus, we elucidated the recognition mechanisms of pathogen-derived lipid molecules in plants.