The plant cell wall consists of a complex network of proteins and polysaccharides including cellulose, pectins and hemicelluloses which are degraded and modified by an arsenal of plant and fungal enzymes secreted during the interaction, generating cell wall derived oligosaccharides some of which having elicitor activities. Upon Arabidopsis thaliana-Botrytis cinerea interaction, although most of the oligosaccharides come from homogalacturonan degradation1, we discovered that a fucosylated xyloglucan oligosaccharide was accumulated and more surprisingly, that seven phosphorylated glycans were also concomitantly produced. Further structural characterization showed that they correspond to inositol-phosphoryl-glycans originating from the hydrolysis of polar heads of Series A to H glycosyl inositol phosphoryl ceramides presumably via a phospholipase C activity. Purification of the most abundant of these inositol phosphoryl ceramides followed by A. thaliana leaf infiltration showed that the ones deriving from Series G and H glycosyl inositol phosphoryl ceramides are able to activate plant defense