Putative virulence factors of Botrytis cinerea acting as a wound pathogen

Abstract The grey mold fungus, Botrytis cinerea , is a wound pathogen of worldwide distribution, and causes rots of almost all fruits and vegetables. The fungus can also penetrate directly from appressoria to cause severe losses to growers of flowers. B. cinerea secretes a number of inducible attack enzymes which can degrade host cell walls to widen the infection, including β-glucosidase, pectin methylesterase, the polygalacturonases, and aspartate proteinase; laccase and benzyl alcohol oxidase appear to have roles of detoxifying compounds derived from the host during pathogenesis, a function that we believe enhances the virulence of the pathogen. With additional research, several oxidases may also become a part of the virulence group. Much more work is needed, in particular the analysis of mutants, to assign formally the roles suggested here.