The presence of ochratoxin A in dried fruits is possible due to contamination by strains of the Aspergillus niger species aggregate. We analysed by RAPD and β -tubulin sequences the genetic relationships among 51 isolates from the A. niger aggregate collected from dried fruit samples e.g. black sultana, dates, figs and plums in different countries. A. niger sensu stricto, A. foetidus and A. tubingensis were found, but A. niger sensu stricto was the most prevalent species that was found in all fruit substrates of all geographical origins. A. tubingensis isolates, which were the second most frequent, were subdivided into two subgroups IA and IB. RAPD profiles, three single nucleotide polymorphisms in the region β -tub2 of the β -tubulin gene and other three in the region β -tub1 clearly discriminated the two groups of this species. Although it is still premature to assign a new taxonomic rank to these groups, our result may explain the incongruence in the literature about the capability of A. tubingensis to produce ochratoxin A.
Full conference title:
161st Society for General Microbiology
- SGM 161st (2007)