Identification of Fungal Pathotypes Associated with Skin Disorders of Citrus Reticulata Blanco Through Classical and Molecular Approach

Abstract

Citrus reticulata Blanco (kinnow) is an important fruit crop of Pakistan playing pivotal role in its export economy. Due to various pathogens the quality of fruit gets diminished. One of such problem includes the occurrence of various skin disorders which leads to the rejection of fruit in international market. This study was designed in order to identify the pathogens that ruin the peal of Citrus reticulata Blanco (kinnow) in order to improve its quality. About twenty six sampled fruits of Citrus reticulata having damaged skin were obtained from the orchards of Sargodha. The samples were classified into groups on the basis of physical appearance of lesions on peal and the disease severity was then identified. Both classical and molecular method was used for identification of pathogens. Under classical approach the infected sections from the skin of kinnow was utilized to grow fungal colonies on generalized media, i.e. potato dextrose agar, from which six fungal colonies were also isolated and studied further. Under molecular approach direct DNA was isolated from the infected skin of sampled fruits by using CTAB method. The pathogens being identified through classical approach includes: Penicillium sp., Aspergillus flavus, Aspergillus niger, Alternaria sp., Lasiodiplodia theobromae, Fusarium sp. After sequencing of DNA the pathogen species identified includes fungal Colletotrichum sp. These pathogens are involved in deterioration the skin of Citrus reticulate. They can either attack the healthy fruit leading to various infections or they can enter through various lesions caused by physical stress and worsen the condition