Colletotrichum Species Causing Cyclocarya paliurus Anthracnose in Southern China

Cyclocarya paliurus, native to China, is a medicinal and edible plant with important health benefits. Anthracnose is an emerging disease in southern China that causes severe economic losses and poses a great threat to the C. paliurus tea industry. However, to date, the species diversity of pathogens causing C. paliurus anthracnose has remained limited. From 2018 to 2022, a total of 331 Colletotrichum isolates were recovered from symptomatic leaves in eight major C. paliurus planting provinces of southern China. Phylogenetic analyses based on nine loci (ITS, GAPDH, ACT, CHS-1, TUB, CAL, HIS3, GS and ApMat) coupled with phenotypic characteristics revealed that 43 representative isolates belonged to seven known Colletotrichum species, including C. brevisporum, C. fructicola, C. gloeosporioides sensu stricto, C. godetiae, C. nymphaeae, C. plurivorum and C. sojae. Pathogenicity tests demonstrated that all species described above were pathogenic to wounding detached leaves of C. paliurus, with C. fructicola being the most aggressive species. However, C. brevisporum, C. plurivorum and C. sojae were not pathogenic to the intact plant of C. paliurus. These findings reveal the remarkable species diversity involved in C. paliurus anthracnose and will facilitate further studies on implementing effective control of C. paliurus anthracnose in China.