Filamentous fungi associated with the brown mussel, Perna perna (Bivalvia: Mytilidae), off the coast of Rio de Janeiro, Brazil

Abstract

ABSTRACT Bivalves are known to be infected by filamentous fungi, many of which have pathogenic and toxicogenic properties, and may represent a risk to human health. The present study investigated the mycological characteristics of Perna perna obtained from Guanabara Bay, Brazil. The mussels were sealed individually in sterile bags, weighed and measured, and the internal organs were examined. The organs were grown in different culture media. All but one of the 31 mussels (96.7%) examined contained fungi, and a total of 84 fungal colonies were isolated. The genera identified were Aspergillus (40.5%), Didymella (35.7%), Penicillium (10.7%), Aureobasidium (1.2%), Cladosporium (1.2%) and Phaeoisaria (1.2%). The molecular sequences obtained 99.8 and 100% identity with Didymella sp., Phaeoisaria sp. and Aureobasidium pullulans, and were deposited in GenBank. This is the first record of Didymella and Phaeoisaria in a bivalve. The digestive gland was the organ with the greatest diversity of fungi genera. A number of the fungi identified here, as Aspergillus awamori, Aspergillus japonicus, Aspergillus niger, Aspergillus versicolor and Aspergillus sydowii, are known to produce mycotoxins and others are opportunistic forms, which reinforces the need for the systematic monitoring of the study area to guarantee the safe exploitation of these bivalves for human consumption.