The Biocontrol Root-Oomycete, , Triggers Grapevine Resistance and Shifts in the Transcriptome of the Trunk Pathogenic Fungus, .

The worldwide increase in grapevine trunk diseases, mainly esca, represents a major threat for vineyard sustainability. Biocontrol of a pioneer fungus of esca, , was investigated here by deciphering the tripartite interaction between this trunk-esca pathogen, grapevine and the biocontrol-oomycete, . When colonizes grapevine roots, it was observed that the wood necroses caused by were significantly reduced. Transcriptomic analyses of plant and fungus responses were performed to determine the molecular events occurring, with the aim to relate degradation of wood to gene expression modulation. Following -root colonization, major transcriptomic changes occurred both, in the grapevine-defense system and in the -virulence factors. Grapevine-defense was enhanced in response to attacks, with acting as a plant-systemic resistance inducer, promoting jasmonic/ethylene signaling pathways and grapevine priming. pathogenicity genes, such as those related to secondary metabolite biosynthesis, carbohydrate-active enzymes and transcription regulators, were also affected in their expression. Shifts in grapevine responses and key-fungal functions were associated with the reduction of wood necroses. This study provides evidence of wood fungal pathogen transcriptional changes induced by a root biocontrol agent, , in which there is no contact between the two microorganisms.