1Thomas, B. T., *1Coker, M. O., 1Popoola, O. D., 1Adesetan, T. O., 1Banjo, O. A., 1Taiwo, O. S., 1Popoola, K. E., 2Thomas, A. N., 1Adegbe, G. M., and 3Owolabi, S. L.
1Department of Microbiology, Olabisi Onabanjo University, Ago-Iwoye, Ogun State, Nigeria
2Department of Animal Production, Olabisi Onabanjo University, Ago-Iwoye, Ogun State, Nigeria
3Department of Science Laboratory Technology (Microbiology Unit), Gateway Polytechnic, Saapade, Ogun State, Nigeria
*Correspondence to: olawunmi.coker@oouagoiwoye.edu.ng; +2349054006625; ORCID ID: https://orcid.org/0000–0003–0937-7755
Abstract:
Background: The importance of RAPD in revealing genetic diversity among ochratoxigenic strains of Aspergillus carbonarius lies in its ability to provide critical information that can support the development of effective strategies to limit ochratoxin A contamination in agricultural produce. This study therefore focused on evaluating the genetic diversity of 20 A. carbonarius strains previously isolated in an earlier investigation.
Methodology: This study focused on evaluating the genetic diversity of 20 A. carbonarius strains previously isolated in an earlier investigation. A total of 26 RAPD primers were initially screened to determine optimal annealing temperatures and to identify those that produced clear, consistent, and reproducible banding patterns. Primers meeting these criteria were subsequently employed in genetic analysis, following standard RAPD protocols.
Results: The obtained results revealed that 7 RAPD primers gave clear and good polymorphisms at the optimal PCR amplification conditions between 36oC and 40oC. These 7 primers generated 18 distinctive RAPD loci from the 20 A. carbonarius isolates. The analysis of population structure at the geopolitical region of Ogun State revealed that the intra-site genetic variation (range=0.02 to 0.33) made up most of the genetic variation observed (82.0%). The magnitude of the overall variation arising from site-level divergence (GST) ranged from 0.01 to 0.42, suggesting minimal site-level population structure. The phylogenetic relationships among the 20 A. carbonarius isolates revealed that none of the isolates exhibited genetically distinct clusters.
Conclusion: The high genetic variation detected among ochratoxigenic A. carbonarius strains underscores the biotechnological importance of RAPD-based molecular characterization for strain-level discrimination, biosafety assessment, and targeted ochratoxin A risk management, thereby supporting informed strain selection and application in fungal biotechnology.
Keywords: Aspergillus carbonarius, Ochratoxin, Genetic Diversity, RAPD
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