Control of Penicillium expansum by an epiphytic basidiomycetous yeast

Postharvest biocontrol agents are considered a viable alternative to the use of synthetic chemicals as demonstrated by extensive research conducted by scientists and companies worldwide. In the present investigation, the biocontrol potential of a carotenoid-producing basidiomycetous yeast isolated from table grape flowers was analyzed. The strain RY1 proved to be Sporobolomyces roseus. In vitro and in vivo tests were conducted to assess its efficacy against Penicillium expansum, one of the most important postharvest pathogens and producer of the mycotoxin patulin. The yeast proved to control both fungal growth and patulin production, and, in addition, to greatly affect disease incidence and severity on apples. Its mode of action is presumably related both to the competition for nutrients and the production of antifungal volatiles. As such, although further large-scale trials are needed, our S. roseus strain represents a potential interesting biocontrol agent to be applied after harvest.