Diversity and pathogenicity of Colletotrichum species causing anthracnose on Cunninghamia lanceolata

Chinese fir (Cunninghamia lanceolata) is a fast-growing tree species with high economic value. Anthracnose caused by Colletotrichum species poses a serious threat to Chinese fir production. To investigate the Colletotrichum species associated with anthracnose on Chinese fir, a survey was conducted from 2016 to 2020 in China. A total of 52 Colletotrichum isolates was collected from six different provinces: Fujian, Guangdong, Jiangsu, Jiangxi, Shandong and Zhejiang. These isolates were identified using morphological and multilocus phylogenetic analyses with the concatenated sequences of the rDNA internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), chitin synthase (CHS-1), actin (ACT), beta-tubulin (TUB2), calmodulin (CAL) and the intergenic region between Apn2 and Mat1-2-1 (ApMat). Colletotrichum cangyuanense, C. fructicola, C. gloeosporioides, C. karstii and C. siamense were revealed to be associated with anthracnose on Chinese fir. Pathogenicity tests showed that there were significant differences in the pathogenicity of these Colletotrichum species on the host plants. To our knowledge, this study reports the pathogen diversity of anthracnose on Chinese fir for the first time.