RESUMO
Aspergillus section Nigri populations isolated from seven growing regions from Argentina were characterized by sequencing in order to identify species responsible for production of ochratoxin A (OTA) and fumonisins (FB(s)). Sequences of genes encoding calmodulin, ß-tubulin, the second largest subunit of RNA polymerase II and translation elongation factor 1 alpha were analysed. The phylogenetic analysis showed the presence of six lineages: A. carbonarius, A. tubingensis, A. niger, A. japonicus, A. homomorphus and A. foetidus grouped in four major clusters. The molecular tools used allowed the identification for the first time of A. homomorphus from vineyards. OTA production confirmed the importance of A. carbonarius as the main ochratoxigenic species isolated and, to a variable degree, of A. niger and A. tubingensis, which were by far the most commonly occurring species on grapes in Argentina. The only strains able to produce OTA and fumonisins (B(2)-B(4)) belong to the A. niger cluster.
Assuntos
Aspergillus/metabolismo , Fumonisinas/metabolismo , Ocratoxinas/metabolismo , Argentina , Aspergillus/classificação , Aspergillus/genética , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Fumonisinas/química , Ocratoxinas/química , Filogenia , Tubulina (Proteína)/genética , Tubulina (Proteína)/metabolismo , Vitis/microbiologiaRESUMO
Twenty-five samples of maize kernels collected at harvest time from geographically different corn fields in Peru, were examined for the occurrence of toxigenic Fusarium species. The most frequently recovered species were F. subglutinans (48%), F. moniliforme (46%), and F. equiseti (5%). Other Fusarium species isolated (up to 1%) included F. graminearum, F. acuminatum, F. solani, F. oxysporum, and F. culmorum. Assays of Fusarium culture extracts using Artemia salina larvae, showed F. subglutinans as one of the most toxigenic species, and its toxicity was mostly correlated to the capability to produce beauvericin (BEA). All eight tested isolates of F. subglutinans grown on autoclaved corn kernels produced BEA (from 50 to 250 mg/kg) as well as moniliformin (M) (from 70 to 270 mg/Kg). This is the first report on BEA and M production by maize isolates of F. subglutinans from South America.