Influence of the region of origin on the mycobiota of grapes with emphasis on Aspergillus and Penicillium species

A three-year study was undertaken to investigate the fungal species present on the surface of grape berries from Portuguese vineyards in four winemaking regions. Emphasis was given to Aspergillus and Penicillium species due to their relevance for mycotoxin production. From the 3517 fungal strains detected 27 genera were identified. The region of origin markedly influenced the spoilage fungal population to which berries are exposed. The main differences found were in the incidence of A. niger aggregate, Botryis cinerea and Penicillium species (P. brevicompactum, P. citrinum, P. glabrum/spinulosum, P. expansum, P. implicatum and P. thomii). In more humid climates, Botrytis seems to be the main pathogen and spoiling agent, and the incidence of black Aspergillus is minimal. The most important mycotoxin-producing species found was A. carbonarius, which is an ochratoxin A producer. The present study provides a detailed description of the fungi found on the berry surface of Portuguese grapes and shows the Aspergillus and Penicillium species, which vary significantly by geographic origin. This is of crucial importance to understand fungal hazards for grapes and wine and to the knowledge of field ecology of the species.