Morphological and molecular identification of fungi isolated from spoilt apples in Ota metropolis

Spoilage of apples continues to be a significant issue in the fruit industry. This study aimed to isolate and identify fungal species on deteriorated apples collected from three different locations in Ota market, Ota, Ogun State, Nigeria. A total of eighteen (18) samples of red delicious and Granny Smith apples with obvious spoilage were collected, and their surfaces were sterilized using 85% ethanol. After that, the samples were cultivated on potato dextrose agar (PDA) supplemented with 30 mg/l of chloramphenicol, and incubated at 30 °C for five to seven days. From the subcultures of the primary plates, pure fungal cultures were obtained and were identified by morphological characterization and internal transcribed spacer (ITS1/ITS4) gene method. Ten fungi that cause spoilage in apples have been identified and grouped into six distinct classes. Among the 40 isolates, the most common one was Trametes polyzona strain MT9, accounting for 27.5% of the total isolates. The second most prevalent isolate was Geotrichum candidum strain MT10, with six isolates, representing 15% of the total. The least frequent was Fusarium sp. strain MT3, with only one isolate, amounting to 2.5%. It was in this connection, that a sequence analysis of the ITS regions of the nuclear-encoded rDNA was conducted, revealing significant alignments with Aspergillus sp., Lasiodiplodia theobromae, Curvularia aeria, and Trametes polyzona. This research investigation sought to elucidate the relationships between specified species, yielding a biocontrol strategy for mitigating fruit deterioration and conserving quality.