Occurrence and biodiversity of Aspergillus section Nigri on ‘Tannat’ grapes in Uruguay

•The occurrence of Aspergillus uvarum was reported for the first time in South America.•Aspergillus welwitschiae showed dominance within the A. niger aggregate.•No Aspergillus carbonarius was isolated.•A PCR-RFLP method was developed to identify black Aspergilli to species level.

Ochratoxin A (OTA) is a nephrotoxic mycotoxin which has been found worldwide as a contaminant in wines. It is produced on grapes mainly by molds from Aspergillus section Nigri. This study has demonstrated for the first time the occurrence of black aspergilli on Tannat grapes from Uruguay, in a two year survey. Aspergillus uvarum (uniseriate) and Aspergillus welwitschiae (from Aspergillusniger aggregate) were the prevalent species whereas Aspergillus carbonarius which is considered the main OTA producing species was not detected. OTA production in culture medium was evaluated for native isolates from A. niger aggregate and compared to levels produced by a type strain of A. carbonarius. This work also includes the development of quick and easy molecular methods to identify black aspergilli to species level, avoiding sequencing.