Morphological and Molecular Identification of Fungi Isolated From Spoilt Apples in OTA Metropolis

Abstract

The spoilage of apples remains a prevalent issue that significantly impacts the fruit industry. This study aimed to isolate and identify fungal species from deteriorated apples collected from three different locations in Ota market, Ota, Ogun State, Nigeria. Eighteen samples of red delicious and Granny Smith apples with obvious spoilage were collected and surface sterilized using 85% ethanol. The samples were then cultured on potato dextrose agar supplemented with chloramphenicol (30 mg/l) and incubated for 5–7 days at 30°C. Pure cultures of the resulting fungal colonies were obtained from the subcultures of the primary plates. The identification of fungi at the genus level was carried out through macroscopic and microscopic examinations, which included colony colour, shape, hyphae, conidia, conidiophores, and arrangement of spores. The fungal DNA was extracted and amplified using specific internal transcribed spacer primers (ITS1/ITS4) via PCR. A set of ten apple fruit spoilage fungi have been identified and classified into six distinct classes. From 40 isolates, the most prevalent isolate was Trametes polyzona strain MT9, accounting for 27.5%. Secondly, Geotrichum candidum strain MT10 had six isolates, representing 15%, while the least frequent was Fusarium sp. strain MT3, with only one isolate, amounting to 2.5%. Additionally, 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 aids in the development of effective control and preservation strategies aimed at reducing the incidence of spoilage and preserving the quality of the fruit.