Molecular Identification of Pathogens Causing Anthracnose on Shatian Lemon in Guangzhou City

Objective  The study aimed to clarify the types of pathogens causing anthracnose on Shatian lemon, with a view to providing guidance for the prevention and control of anthracnose on Shatian lemon in field.

Method  The collected anthracnose samples were isolated and purified, and 9 strains of the pathogens ST2-1, ST2-2, ST2-3, ST3-1, ST3-2, ST3-3, ST4-1, ST4-1, ST4-2, and ST4-3 of anthracnose on Shatian lemon were obtained. Then puncturing and spraying inoculation methods were used to test the pathogenicity of the above strains, and their ITS, TUB2, ACT, LSU, GAPDH and CAL fragments were cloned for multi-gene joint identification.

Result  ST2-1, ST2-2, ST2-3, ST3-1, ST3-2, ST3-3, ST4-1, ST4-2 and ST4-3 are all highly pathogenic. The biological characteristics and phylogenetic tree indicated that ST2-1, ST2-2 and ST2-3 belonged to Colletotrichum siamense, ST3-1, ST3-2 and ST3-3 belonged to Colletotrichum cliviicola, ST4-1, ST4-2 and ST4-3 belonged to Colletotrichum fructicola.

Conclusion  Based on the morphological characteristics and molecular biological identification results, the pathogens causing anthracnose on Shatian lemon in Guangzhou were C.siamense, C.cliviicola and C. fructicola, in which C. siamese was isolated from the diseased fruit of Shatian lemon, C. cliviicola and C. fructicola were isolated from the diseased leaves of Shatian lemon, and it was the first report in the world that C. cliviicola could cause anthracnose on citrus plants.