Oligosaccharides from Botrytis cinerea and Elicitation of Grapevine Defense

An extract from Botrytis cinerea culture filtrate was sprayed on grapevine plants (Vitis vinifera) to investigate its potential to stimulate defense reactions. The extract triggered the induction of genes encoding pathogenesis-related (PR) proteins as chitinases (CHIT), polygalacturonase-inhibiting protein (PGIP), serine proteinase inhibitor (PIN), and enzymes involved in phytoalexin synthesis as phenylalanine ammonia-lyase (PAL) and stilbene synthase (STS). Correlated to the up-regulation of these latter genes, stilbene content increased in treated leaves. Consequently, treatment of grapevine leaves with the fungal extract triggered protection toward Plasmopara viticola and Erysiphe necator, the causal agents of grapevine downy and powdery mildews, respectively. Disease severity was significantly reduced in elicited plants, approximately 61 % for downy mildew and 83 % for powdery mildew. This approach could represent a valuable strategy to protect grapevine from diseases as an alternative or complementary method to the use of pesticides