Molecular Identification and Distribution of Fungal Species Associated with Stored Pearl Millet (Pennisetum glaucum (L.) R. Br.) in Ogbomoso, Oyo State, Nigeria

Abstract

Pearl millet (Pennisetum glaucum L. R. Br.), a member of the Poaceae family, is the sixth most important cereal crop globally and a major staple in northern Nigeria due to its high nutritional values and gluten-free properties. However, fungal contamination during storage poses serious economic and public health concerns, particularly due to the production of mycotoxins. This study investigated the occurrence and diversity of fungal species associated with stored pearl millet seeds collected from five major markets in Ogbomoso, Oyo State, Nigeria. Pearl millet seeds (480g) were collected in each market, surface-sterilized, moistened with sterile distilled water, and stored for seven days to induce spoilage. Seeds were plated on Potato Dextrose agar amended with streptomycin and incubated for three days at 25±2°C. The emerging fungi were sub-cultured to obtain pure isolates and identified using morphological characteristics and molecular analysis targeting the Internal Transcribed Spacer (ITS) region. Sequence analysis through BLAST confirmed five fungal species: Aspergillus tamarii, Fusarium arcuatisporum, Penicillium griseofulvum, Curvularia lunata, and Pseudopestalotiopsis theae. A. tamarii had the highest frequency of occurrence (29.73%), while F. arcuatisporum had the lowest frequency (13.51%). Idi-Abebe market recorded the highest fungal distribution (40.54%), likely due to poor storage infrastructure. The predominance of mycotoxigenic species underscores the need for improved post-harvest handling, routine mycological surveillance, mycotoxin risk assessment, and storage hygiene to enhance the safety and shelf life of stored pearl millet within local value chains.