Molecular Investigations of Food-Borne Cladosporium and Fusarium Species from Nigeria

A sampling of contaminated foodstuffs throughout southwest Nigeria yielded three fungalisolates belonging to the genus Fusarium and two belonging to the genus Cladosporium. In this study we subjected these isolates to various molecular investigations. The morphological species identifications were confirmed or refined with BLAST queries for sequences from two genomic regions (translation elongation factor-1 α and ITS). BLAST results uncovered species identification inconsistencies for one Fusarium isolate, SRRC1606, and for both Cladosporium isolates based on the examined loci. Using additional species sequences obtained from Gen Bank, the phylogenetic associations for each genomic region were explored and observed species haplotype associations for the Fusarium sequences; however, this was not the case for the Cladosporium sequences. There was evidence of recombination in both loci for the Fusarium species, but only in the translation elongation factor locus for the Cladosporium sample population. Fusarium coalescent analyses for both loci inferred two lineages, one containing only F. oxysporum sequences and the other containing the remaining species examined. These same analyses for the Cladosporia inferred ancient segregation of one lineage, containing only the outgroup taxa, from a second lineage that exhibited recent divergence events among the other taxa examined. Mycological population dynamics and analyses can achieve a better understanding of interventions to protect consumers from contaminated foods.