Black Aspergilli, which comprises species belonging to Aspergillus section Nigri, are distributed worldwide and have a significant impact on human society due to both their beneficial and harmful effects. Although black Aspergilli are mainly isolated from the soil, they are among the most common fungi causing food spoilage. Recently, several studies focused on this group of organisms due to their role as causative agents of black rot of grapes and subsequently cause ochratoxin A contamination. Herein an overview on the occurrence, biodiversity, ecology, toxigenic potential and genetic aspects relevant to ochratoxin production and molecular detection of black Aspergilli in grapes was presented. Nine different black Aspergillus species have been identified on grapes with different secondary metabolites profiles. These species are often difficult to identify with classical methods. The polyphasic approach used in our studies led to characterization of 3 new species occurring on grapes: A. brasiliensis, A. ibericus and A. uvarum. However, the main source of ochratoxin A contamination in grapes is Aspergillus carbonarius, followed by A. niger and A. tubingensis. The genetic aspects of ochratoxin production evidenced that a polyketide synthase is likely to be linked to ochratoxin production, in a similar way as in the cases of other mycotoxins such as fumonisins and aflatoxins. Furthermore, it was found that genes in different ochratoxigenic fungi like Penicillium and Aspergillus are dissimilar. Although four genes of ochratoxin biosynthetic pathway have recently been characterized from Penicillium nordicum, no gene proved to be involved in ochratoxin biosynthesis has yet been identified in A. carbonarius. Management of ochratoxin risk in the wine food chain is a challenging task. Various biotic, abiotic, agronomical and environmental factors play an important role in relation to ochratoxin accumulation in grapes and wine. Possible prevention and reduction strategies in the wine food chain have been proposed, and main critical pontrol points and preventive measures to be taken in account in high OTA risk areas is presented.
Aspergillus in grapes:ecology, biodiversity and genomics
Perrone G;Gallo A;Susca A;
2009
Abstract
Black Aspergilli, which comprises species belonging to Aspergillus section Nigri, are distributed worldwide and have a significant impact on human society due to both their beneficial and harmful effects. Although black Aspergilli are mainly isolated from the soil, they are among the most common fungi causing food spoilage. Recently, several studies focused on this group of organisms due to their role as causative agents of black rot of grapes and subsequently cause ochratoxin A contamination. Herein an overview on the occurrence, biodiversity, ecology, toxigenic potential and genetic aspects relevant to ochratoxin production and molecular detection of black Aspergilli in grapes was presented. Nine different black Aspergillus species have been identified on grapes with different secondary metabolites profiles. These species are often difficult to identify with classical methods. The polyphasic approach used in our studies led to characterization of 3 new species occurring on grapes: A. brasiliensis, A. ibericus and A. uvarum. However, the main source of ochratoxin A contamination in grapes is Aspergillus carbonarius, followed by A. niger and A. tubingensis. The genetic aspects of ochratoxin production evidenced that a polyketide synthase is likely to be linked to ochratoxin production, in a similar way as in the cases of other mycotoxins such as fumonisins and aflatoxins. Furthermore, it was found that genes in different ochratoxigenic fungi like Penicillium and Aspergillus are dissimilar. Although four genes of ochratoxin biosynthetic pathway have recently been characterized from Penicillium nordicum, no gene proved to be involved in ochratoxin biosynthesis has yet been identified in A. carbonarius. Management of ochratoxin risk in the wine food chain is a challenging task. Various biotic, abiotic, agronomical and environmental factors play an important role in relation to ochratoxin accumulation in grapes and wine. Possible prevention and reduction strategies in the wine food chain have been proposed, and main critical pontrol points and preventive measures to be taken in account in high OTA risk areas is presented.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.