Molecular analysis of Aspergillus section Flavi isolated from Brazil nuts.
Brazil nuts are an important export market in its main producing countries, including Brazil, Bolivia, and Peru. Approximately 30,000 tons of Brazil nuts are harvested each year. However, substantial nut contamination by Aspergillus section Flavi occurs with subsequent production of aflatoxins. In our study, Aspergillus section Flavi were isolated from Brazil nuts (Bertholletia excelsa), and identified by morphological and molecular means. We obtained 241 isolates from nut samples, 41% positive for aflatoxin production. Eighty-one isolates were selected for molecular investigation. Pairwise genetic distances among isolates and phylogenetic relationships were assessed. The following Aspergillus species were identified: A. flavus, A. caelatus, A. nomius, A. tamarii, A. bombycis, and A. arachidicola. Additionally, molecular profiles indicated a high level of nucleotide variation within β-tubulin and calmodulin gene sequences associated with high genetic divergence from RAPD data. Among the 81 isolates analyzed by molecular means, three of them were phylogenetically distinct from all other isolates representing the six species of section Flavi. A putative novel species was identified based on molecular profiles.
Departamento de Biologia Geral, Universidade Estadual de Londrina, P.O. Box 6001, Londrina, 6051-970, Brazil.
Juliana Soares
JS
Gonçalves
Lara Munique
LM
Ferracin
Maria Lucia
ML
Carneiro Vieira
Beatriz Thie
BT
Iamanaka
Marta Hiromi
MH
Taniwaki
Maria Helena
MH
Pelegrinelli Fungaro
D000348:Aflatoxins / Q000378:metabolism; D001230:Aspergillus / Q000145:classification* / Q000166:cytology / Q000235:genetics* / Q000302:isolation & purification; D031383:Bertholletia / Q000382:microbiology*; D001938:Brazil; D002147:Calmodulin / Q000235:genetics; D016000:Cluster Analysis; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D014644:Genetic Variation; D008969:Molecular Sequence Data; D010802:Phylogeny; D019105:Random Amplified Polymorphic DNA Technique; D017422:Sequence Analysis, DNA; D014404:Tubulin / Q000235:genetics
D000348:Aflatoxins; D002147:Calmodulin; D004271:DNA, Fungal; D014404:Tubulin