Molecular Characterization of Fungal Isolates Associated with Senecio biafrae (Oliv. & Hiern) Collected in Ibadan Metropolis

Abstract

Background and Aims: Senecio biafrae is an important leafy vegetable valued for its nutritional and medicinal uses in West Africa. However, it is highly prone to fungal spoilage during handling and storage, which reduces quality and may pose health risks through possible mycotoxin contamination. This study aims to profile the fungi associated with Senecio biafrae in retail and determine the potential for toxin contamination in the isolates. Place and Duration of Study: Samples were collected from markets in Ibadan and analyses were carried out in the Department of Biological Sciences, Lead City University, Ibadan between May 2025 and August 2025. Methodology: Molecular characterization of fungi associated with Senecio biafrae in Ibadan metropolis (Nigeria) was carried out using apparently fresh samples collected from retailers in four markets. Portions from the samples were cut, surface-sterilized, rinsed and dried on sterile filter paper. These samples were plated directly on Potato Dextrose Agar (PDA) and observed for fungal growth. Pure cultures were obtained by repeated subculturing, while identification was done macroscopically, microscopically and with molecular techniques using the Internal Transcribed Spacer (ITS) region of the fungal Deoxyribonucleic Acid (DNA). Furthermore, aflatoxin content of the isolates was carried out using Enzyme Linked Immunosorbent Assay (ELISA) method. Results: Molecular identification and characterization through DNA sequencing validated the morphological identity of the six fungal isolates as Aspergillus niger, Aspergillus brunneoviolaceus, Penicillium oxalicum, Aspergillus fumigatus, Aspergillus tamarii, and Mucor irregularis. Aspergillus niger had the highest percentage of occurrence (31.71%), followed by Aspergillus brunneoviolaceus (26.83%), then, Penicillium oxalicum (19.51.%) and the least occurring were Aspergillus fumigatus (7.32%), Aspergillus tamarii (7.32%) and Mucor irregularis (7.32%). The Aflatoxin content in the samples ranged from 6.8 ppb (Oje market) to 0.2ppb (Mapo market). Conclusion: With the fungal population and diversity it becomes important for regulatory authorities and retailers to ensure the proper handling of food especially during storage and retail.