Ability of Pythium oligandrum strains to protect Vitis vinifera L., by inducing plant resistance against Phaeomoniella chlamydospora , a pathogen involved in Esca, a grapevine trunk disease

•P. oligandrum inocula colonized the rhizosphere throughout the experimental period.•Plant root system colonization by P. oligandrum reduced P. chlamydospora necroses.•Plant molecular responses differed according to treatments.•P. oligandrum enhanced certain gene expression in P. chlamydospora infected plants.