Detection and molecular identification of Colletotricum species causing anthracnose disease of some plants in Khuzestan province (Iran)

Summary
Anthracnose is a general term for sunken lesions and blights on stems, leaves and fruits which causes economic damage to agricultural products. This study, conducted to identify Colletotrichum species associated with anthracnose symptoms on some plants in Khuzestan province (Iran) using morphological and molecular methods. During 2016–17, 40 leaf and fruit samples showing anthracnose symptoms (from alfalfa, banana, sour lemon, orange and strawberry) were collected and surveyed for morphological study. Accordingly, 12 isolates of the genus Colletotrichum were obtained. Mycelial biomass of the isolates were produced in PDB and freeze-dried. DNA was extracted using an organic method based on phenol and chloroform. The ITS and partial regions of the 28S-D1/D2 and Tub2 were amplified using universal and specific primers and sequenced. Obtained sequences were compared  with index sequences belonging to the type strains in GenBank by BLASTn algorithm and phylogenetic analysis (maximum likelihood algorithm). The species of Colletotrichum gloeosporioides, C. karstii, C. musae, C. nymphaeae, and C. truncatum were identified along with their morphological study. In phylogenetic tree constructed based on the ITS and Tub2 combined dataset, Colletotrichum isolates under study were clustered with type strain of each species and formed monophyletic clades with 96–99% bootstrap support.