Detection of Colletotrichum capsici causing chili anthracnose through morphological and species-specific marker and its genetic diversity

Anthracnose of chili is caused by different Colletotrichum species. Precise detection of the species responsible is essential in strategizing disease management and control. We collected ten Colletotrichum isolates causing chili anthracnose to identify the organism by species-specific SSR marker, characterized them morphologically and determined genetic diversity by RAPD-PCR technique. The fungal pathogens were taken from anthracnose lesions without visible spores. Identification and characterization based on the morphology of the fungal colony, and the dimension and shape of the conidia formed were done. Two pathogen species-specific microsatellite loci were used for molecular detection. As was expected, the markers amplified DNA bands of 394 and 447bp, which confirmed the pathogen as Colletotrichum capsici. Five RAPD primers generated 64 distinct bands, of which 84.38% showed polymorphism. UPGMA Dendrogram segregated ten isolates into two distinct clades. Wide variability was detected among the isolates indicating the existence of different pathotypes of anthracnose causing C. capsici in Bangladesh. This paper identifies Colletotrichum capsici as the causal agent of chilli anthracnose in Bangladesh by molecular and conventional methods and detects molecular diversity among the C. capsici isolates. The information obtained has potential application in the detection and effective control of chill anthracnose.