Diversity of Mycotoxin-Producing Fungi in Leafy and Fruit Vegetables Sold in Port Harcourt Metropolis, Nigeria

Abstract

Mycotoxins are secondary metabolites produced by fungi and are capable of causing diseases and even death in both humans and other animals. This study investigated the diversity of mycotoxin-producing fungi from leafy (Telfairia occidentalis and Bassica oleracea) and fruit (Solanum lycopersicum and Cucumis sativus) vegetables sold in Port Harcourt metropolis, Nigeria using molecular techniques. The fungi were isolated from vegetable samples showing signs of disease using standard methods. DNA extraction and Polymerase chain reaction were carried out at the molecular laboratory of Regional Centre of Biotechnology and Bioresources research, University of Port Harcourt. The isolates were screened for the presence of mycotoxigenic genes (nor1 (aflatoxin), tri6 (trichothecene), otanps (Ochratoxin A), fum13 (fumonisin) and ZEA (zearalenone)) using PCR technique. The isolates containing mycotoxins were identified using ITS gene sequences. Ten out of the eighteen isolates were positive for four (nor1, tri6, otanps and fum13) out of the five mycotoxigenic genes screened. The nine isolates included fungi belong to six genera: Meyerozyma, Pithomyces, Fusarium, Trametes, Penicillium and Aspergillus. The ten isolates were classified as Meyerozyma carbbica RCBBR_Sf13, Pithomyces chartarum RCBBR_Sf5, Fusarium falciforme RCBBR_Sf10, Trametes duplexa RCBBR_Sf17, Trametes versicolor RCBBR_Sf2a, Trametes duplexa RCBBR_Mf1, Fusarium longifundum RCBBR_Mf4, Penicillium soosanum RCBBR_Mf7, Aspergillus aflatoxiformans RCBBR_Sf9, Fusarium circinatum RCBBR_Sf3 based on their ITS gene sequences. Their ITS gene sequences have been deposited in GenBank under the accession numbers OR816039-OR816047, with the exception of Fusarium circinatum RCBBR_Sf3 which could not accession. This study has demonstrated that mycotoxin-producing fungi are diverse and widespread in leafy and fruit vegetables sold within Port Harcourt Metropolis. This raises both public health and food security concerns.