Molecular study of pathogenic and saprophytic fungal species on infected parts of Malus pumila L. of district Qilla Abdullah, Balochistan, Pakistan

Abstract

Apple (Malus pumila L) of the family Rosaceae, most cultivated fruit in temperate regions of the world and is used fresh or processed. The apple production is affected by several pathogens including fungi.  The present study was designed to identify disease-causing agents that reduce fruit production in the district Qilla Abdullah of Balochistan, Pakistan, which is the main apple production area of the province. Three varieties of apple: ‘Tur-Kulu’ (‘Red Delicious’), ‘Shin-Kulu’ (‘Golden Delicious’), and ‘Kaja’ were selected. Infected leaf samples were collected from eight different sites of tehsil Gulistan, district Qilla Abdullah. The cultures of fungal micro-flora were grown on two media, potato dextrose agar (PDA), and malt extract agar (MEA) followed by incubation for one week. The resulting colonies were observed under a microscope and identified based on morphological characters. Predominant fungal species was identified through ITS marker and PCR amplification. The isolated pathogens belonged to Zygomycota and Ascomycota divisions. The pathogens found were Aspergillus niger, A. oryzae, A. terrus, Colletotrichum gloeosporioides, Fusarium oxysporum, Mucor spp., Penicillium expansum, and one species of Absidia as well as Rhizopus. Colletotrichum gloeosporioides were predominantly found in all varieties. Morphological and phylogenetic analysis confirmed the identity of Colletotrichum gloeosporioides. As a result of this study, the predominant pathogen species Colletotrichum gloeosporioides is one of the causes of leaf infection in apple varieties.