Identification and characterization of Colletotrichum species associated with mango anthracnose in Taiwan

Mango is widely grown in Taiwan and anthracnose is one of the most important diseases of this crop. The aim of this study was to investigate Colletotrichum species associated with mango and the pathogenicity of these fungal species. From 2006 to 2017, mango tissue from 33 mango orchards were collected. Eighty-seven isolates associated with mango were analyzed preliminarily by comparing partial glyceraldehyde-3-phosphate dehydrogenase sequences. Four species belonging to C. gloeosporioides complex were preliminarily identified, namely C. asianum (68 isolates), C. fructicola (four isolates), C. siamense (eight isolates) and C. tropicale (two isolates). The other five isolates were identified as belonging to the C. acutatum complex. Ten isolates, belonging to different Colletotrichum species according to glyceraldehyde-3-phosphate dehydrogenase sequences prediction, were used for further morphology and multi-gene phylogenetic analysis. Five species were identified, namely C. asianum, C. fructicola, C. siamense, C. tropicale and C. scovillei. All five species showed pathogenicity on fruit, and C. asianum isolates C-1076 and C-1646 as well as C. siamense isolate C-526 caused larger lesions than the other isolates. On mango leaves, C. asianum, C. fructicola, C. siamense and C. scovillei isolates were pathogenic, while C. tropicale isolates, C-141 and C-303, failed to cause significant foliar lesions. In addition, C. siamense isolates C-526 and C-848 caused significantly larger lesions on leaves than other isolates. This study reports the identification and pathogenicity of Colletotrichum species related to mango anthracnose in Taiwan.