MOLECULAR CHARACTERIZATION OF PHYLLOPLANE MICROBES ASSOCIATED WITH SWEET POTATO (Ipomoea batatas (L.) LAM.)

The phylloplane of plants are associated with diverse micro-organisms which could be phytopathogens or non-pathogenic beneficial microbes. This study aimed at the isolation, characterization and identification of fungi and bacteria associated with the phylloplane of seven sweet potato varieties (UMUSPO 1, UMUSPO 2, UMUSPO 3, UMUSPO 4, TiS 0.87, Mother delight and King James) using molecular techniques. Leaf samples were collected from field-grown plants and taken to the laboratory for isolation of associated phylloplane microbes. The fungi and bacteria were isolated using Potato Dextrose Agar (PDA) medium and nutrient agar respectively. Deoxyribonucleic acid (DNA) was extracted from the fungi isolated from UMUSPO3 and UMUSPO4 varieties while bacterial DNA was extracted from UMUSPO 4. The genomic DNA was extracted using Zymo Quick-DNA fungal /Bacterial MiniPrep kit. Polymerase Chain Reaction (PCR) amplification targeted the Internal Transcribed Spacer (ITS) gene for the fungi and the 16S gene for the bacteria using universal primer pairs (ITS4 and ITS5 for the fungal DNA, and 27F and 1525R for the bacterial DNA). The sequence of each organism was aligned with the sequences in the National Center for Biotechnology Information (NCBI) database. The result of the alignment revealed that the fungal isolate of UMUSPO3 was 95.07% identical to Trichoderma koningiopsis (AJ27995.1) and the fungal isolate of UMUSPO4 was 91.67% identical to Aspergillus brunneoviolaceus (MI4384816.1). The bacterial isolate of UMUSPO4 was 100% identical to Bacillus cereus (MK120124.1). This study has revealed some of the microorganisms associated with the phylloplane of sweet potato in the study area.