P-182 - Insight into genetic variability in phytotoxin biosynthetic gene clusters of Botrytis cinerea strains underlying its virulence in tomato

Grey mold, caused by the necrotrophic fungal pathogen Botrytis cinerea, is a widespread disease of tomatoes, resulting in reduced yield and post-harvest losses. The pathogen possesses diverse secondary metabolite gene clusters, such as the sesquiterpene botrydial gene cluster and the polyketide-type botcinic acid. Although a role in disease progression has been attributed to such metabolites, the driver for genetic variability in these clusters remains unknown. To initiate this study, we collected and characterized fifteen isolates according to their virulence and sporulation capacity.
A custom-built multispectral phenotyping platform was used to assess infection in detached tomato leaves. These experiments showed that light conditions significantly affected the sporulation and virulence of B. cinerea. Strains inoculated under daylight showed lower sporulation than those under near UV. Strikingly, we found that daylight-inoculated strains were more virulent than near-UV-inoculated strains, although spore amounts were higher under the former conditions. We are optimizing an LC-MS/MS method for detecting and quantifying botrytdial and botcinic acid derivatives. In addition, the two biosynthetic gene clusters will be identified using whole genome sequencing. These data will provide an understanding of genetic variability within these clusters, the first step to exploring their role during the colonization of tomato.