Specific molecular interactions between Vitis vinifera and Botrytis cinerea are required for noble rot development in grape berries

Under peculiar climatic conditions, the beneficial form of the necrotrophic fungus Botrytis cinerea can develop on grape berries as a latent infection, known as noble rot, which induces positive biochemical and metabolic changes in the berries, including an increase in the sugar content and the production of aromatic compounds that improve wine quality. The infected berries undergo rapid withering, which is required to produce famous sweet white wines such as Sauternes and Tokaj. To gain insight into the molecular interactions between grapevine berries (Vitis vinifera) and B. cinerea during the establishment of noble rot, we prepared a large-scale transcriptomics dataset representing noble rot development and carried out a comparative meta-analysis with gray mold infection and natural post-harvest withering. In particular, we artificially induced berry botrytization of two grape varieties (Garganega and Moller-Thurgau) and sampled them at different stages of noble rot for comparative whole-transcriptome analysis, highlighting important common transcriptional reprogramming in both varieties reflecting an accelerated withering process. Simultaneously, we analyzed the modulation of B. cinerea genes and compared the expression profile during noble rot development with the previously reported gray mold infection profile, revealing the onset of an infection process by the fungus in its beneficial form associated with reduced virulence. This, together with the restrained plant defense response observed in botrytized berries, may favour the development of noble rot instead of gray mold. Finally, the comprehensive meta-analysis of gene expression during noble rot infection, gray mold and post-harvest withering led to the identification of key genes specifically modulated during noble rot infection.