Aspergillus flavus: genetic variation, patterns of distribution and substrate specificity
Ramírez-Camejo, Luis Alberto
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Aspergillus flavusis an opportunistic pathogen of humans, animals and plants, characterized by aflatoxin production and tolerance to salinity and high temperature. Recently we have found that A. flavusis common in sea fans (Gorgonia sp.) in waters around Puerto Rico. However the source of inoculum is unclear. Also, it is unclear whether A. flavusstrains demonstrate substrate specificity. Few phylogeographic studies have focused on marine fungi. In this study, we compared genetic similarity between A. flavusstrains isolated from several substrates and sites to determine if there is an association between substrate and phylogeny, and genetic distance vs. geographic distance. DNA was extracted and parts of three genes were sequenced. Ten Amplified Fragment Length Polymorphism (AFLP) combinations were used to fingerprint some of the isolates from sea fans. Phylogenetic relationships were estimated with maximum parsimony (for sequences) and neighbor-joining (for AFLPs). Results showed no correlation between substrate specificity and phylogenetic distribution. A. flavusstrains appear to be generalists. No clade was noted to have a specific phylogeographic distribution, so there was no evidence of endemism in A. flavusstrains. Improved resolution of genetic identity of A. flavusstrains can help us understand the dynamics of opportunistic pathogens and their role in coral reefs.