Colletotrichum fructicola and C. siamense are involved in chilli anthracnose in India

Chilli anthracnose is a major problem in India and worldwide. In this study, we investigated the phylogenetic relationships of 52 fungal isolates associated with chilli anthracnose in southern India. All the 52 isolates were sequenced for partial ITS/5.8S rRNA and glyceraldehyde-3-phosphate dehydrogenase (gapdh) genes and showed affinities with Colletotrichum siamense and C. fructicola within Colletotrichum. gloeosporioides species complex. Further, a reduced subset of 17 selected isolates was made and in a maximum parsimony analysis of a multigene data-set including partial ITS/5.8S rRNA, actin (act), calmodulin (cal), chitin synthase (chs1), gapdh and β-tubulin (tub2) gene sequence data, these fungal isolates clustered with the type strain of C. fructicola, except for strain MTCC 3439 that showed phylogenetic affinities with C. siamense. The pathogenicity tests involving two representative isolates: UASB-Cg-14 and MTCC 3439, confirmed the involvement of C. fructicola and C. siamense in the development of disease symptoms on fresh chilli fruits. This is the first report of the association of C. fructicola and C. siamense in causing chilli anthracnose in India.