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ARS Home » Southeast Area » New Orleans, Louisiana » Southern Regional Research Center » Food and Feed Safety Research » Research » Publications at this Location » Publication #314617
Title: Molecular investigations of food-borne Cladosporium and Fusarium species from Nigeria

Author
item Moore, Geromy
item FAPOHUNDA, STEPHEN - Babcock University

Submitted to: Mycotoxicology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/6/2016
Publication Date: 10/4/2016
Citation: Moore, G.G., Fapohunda, S.O. 2016. Molecular investigations of food-borne Cladosporium and Fusarium species from Nigeria. Mycotoxicology. 3:1-14.

Interpretive Summary: Contaminated foods were sampled from markets across southwestern Nigeria in 2011. Fungal contaminants were isolated and identified morphologically before being submitted into the SRRC fungal collection. Molecular investigations were undertaken to confirm species identity as well as to ascertain species associations through various population analyses. This article offers information relating to the sampled isolates from two fungal genera: Fusaium and Cladosporium. Species from both genera can negatively impact consumers so accurate identification and understanding of their respective inter-specific interactions are important.

Technical Abstract: A sampling of contaminated foodstuffs throughout southwest Nigeria yielded three fungal isolates belonging to the genus Fusarium and two fungal isolates belonging to the genus Cladosporium. In this study we subjected these isolates to various molecular investigations. We were able to confirm or refine our morphological species identifications with BLAST queries for sequences from three genomic regions (beta-tubulin, calmodulin and ITS). BLAST results uncovered a species identification inconsistency for one Fusarium isolate, SRRC1606, based on ITS sequence, and for both Cladosporium isolates based on their beta-tubulin sequences, compared to the other loci. Using additional species sequences obtained from GenBank, we explored phylogenetic associations for each genomic region. We found evidence of recombination in all three loci for the Fusarium species examined, but only in the beta-tubulin locus for our Cladosporium population. Fusarium coalescent analyses for all loci inferred two lineages, with the three Nigerian isolates sharing a lineage that has undergone frequent speciation. These same analyses for the Cladosporia inferred ancient segregation of the two Nigerian isolates from the other species analyzed. Examination of the amino acid coding sequences for the beta-tubulin and calmodulin loci revealed a high degree of residue conservation across all species/genera. Understanding these population dynamics, with relation to fungi that contaminate foodstuffs, may serve to help us better protect consumers from contaminated foods.