Occurrence, Molecular Characterization and Phylogenetic Relationship of Aspergillus Species Isolated from Garri Sold in Benue State, North Central, Nigeria

Abstract

Characterization and identification of molds based on cultural and morphological characteristics are often not reliable and frail with limitations. The occurrence of Aspergillus species in garri on sale in markets in Benue State, Nigeria, was studied by molecular techniques. Aspergillus species were isolated and purified on Potato Dextrose Agar. DNA from the purified isolates was extracted using the ZR fungal DNA miniprep and amplified by PCR mix made up of 12.5 μL of Taq 2X Master Mix. Primer sequences for the fungi characterization were internal transcribed spacers ITS 4 and ITS 5. The phylogenetic tree was plotted between the isolated organisms and reference sequences and evolutionary analysis was conducted in MEGA X. Result revealed that one thousand, six hundred and forty-six Aspergilli were isolated comprising of 980 and 666 isolates from the white and yellow garri respectively. Aspergillus flavus, A. fumigatus, A. niger, A. aculeatinus, and A. aculeatus were identified. Twenty percent (20%) of the strains had aflatoxin D structural gene, 50% amplified AFLP and 70% of the strains expressed AFLQ genes needed for the biosynthesis of aflatoxin B1. Majority of the strains that showed the expression of these structural genes were consistent with Aspergillus flavus. Phylogenetic tree showed a close relationship among the isolates and their most identical sequence in the NCBI database.