A Colletotrichum gloeosporioides Cerato-platanin protein, CgCP1, contributes to the conidiation and plays roles in the interaction with rubber tree.

Colletotrichum gloeosporioides is the causal agent of rubber tree anthracnose and leads to serious losses of natural rubber production. The pathogenesis of C. gloeosporioides on rubber tree remains unknown. Ceratoplatanin proteins are small, secreted cysteine-rich proteins that contribute to virulence and function in plant-fungal interactions. A gene encoding cerato-platanin protein, CgCP1, was identified in C. gloeosporioides. In silico analysis indicated that CgCP1 belongs to a new branch of the cerato-platanin protein family. The CgCP1 knockout mutants (Delta CgCPI) and complementary strain (Res-Delta CgCP1) were generated to investigate its biological function. The results showed that the speed of growth of aerial hyphae was not significantly different among the wild-type (WI), Delta CgCPI, and Res-Delta CgCP1 strains, but conidiation of Delta CgCP1 significantly decreased in comparison with the WT. The pathogenicity test proved that the severity of symptoms caused by Delta CgCPI was reduced significantly compared with those caused by the Res-Delta CgCP1 and WT strains. Additionally, CgCP1 induced necrosis-like cell death on tobacco leaf and accumulation of reactive oxygen species in rubber tree mesophyll protoplasts. Altogether, these data indicate the involvement of C. gloeosporioides CgCP1 in conidiation and the interaction with rubber tree.