Identification and Characterization of Colletotrichum Species Associated with Mango Anthracnose in Guangxi, China

Mango (Mangifera indica) is widely grown across southern China, especially in the provinces of Guangxi, Hainan, Yunnan, Sichuan, and Taiwan. Guangxi itself has over 86,667 ha of mango production. The purpose of this study was to identify Colletotrichum species associated with mango in different parts of Guangxi and examine their pathogenicity on leaves and fruits of mango in vitro. Diseased leaves were collected from 25 mango orchards in different areas of Guangxi province. Sixty-five isolates were obtained from mango leaves with anthracnose symptoms, and these were further characterized based on morphology and DNA sequencing. Twenty-nine isolates from different areas were selected for sequencing and analyses of the internal transcribed spacer region, glyceraldehyde-3-phosphate dehydrogenase, partial actin, β-tubulin, and chitin synthase genomic regions. The most common fungal isolates were these three species: Colletotrichum asianum, C. fructicola, and C. siamense. C. asianum was the most common and widely distributed in Guangxi (51.7%), followed by C. fructicola (37.9%) and C. siamense (10.2%), both found in Tiandong, Tianyang, and Wuming counties. There was no evidence of geographical specialization of the different species. Pathogenicity assays showed that all isolates were pathogenic to mango leaves and fruit (cultivar Tainong). No relationship was found between origin of isolates and their virulence. This is the first description of C. asianum, C. fructicola, and C. siamense as causal agents of mango leaf anthracnose from Guangxi province, China.