Molecular characterisation of pathogenic fungi of maize grains

Abstract

Fungi differ from each other phylogenetically, ecologically, metabolically, biochemically, physiologically and morphologically. Despite industrial, medicinal and agricultural importance of fungi, their identification remains daunting for young mycologists. A study was conducted to identify the common fungal pathogens causing post-harvest contamination of stored maize grains purchased from the Rumuokoro daily market in Port Harcourt, Rivers State. Fungal cultures were isolated and morphologically identified using both standard blotter method and Potato Dextrose Agar (PDA) media. The DNA of the most common fungal isolate, coded M-11, was molecularly characterised using Internal Transcribed Spacer 1 (ITS-1) molecular marker. The M-11 isolate DNA sequence was aligned using the Basic Local Alignment Search Tool for nucleotide (BLASTN) 2.8.0 version of the National Centre for Biotechnology Information (NCBI) database. The amplified DNA sequence of the millet isolates yielded 569 base pairs. The results indicated that the M-11 isolate sequence was 89.34% identical to Aspergillus flavus var. flavus strain CSS 130026 and 88.11% identical to Aspergillus flavus isolate AA 133. The above outcome shows that one of the causal organisms associated with stored maize grains is Aspergillus flavus. It is anticipated that these results will improve on the current information available, provide information for developing effective disease control strategy for alleviating the post-harvest losses caused by Aspergillus flavus and also provide a foundation for further study of potential mycotoxic effect of consuming diseased maize seeds.