Mating and Pathogenicity of the Dominant Colletotrichum Species Associated with Anthracnose Disease of Mango

Anthracnose is one of the main diseases of mango, which seriously affects the yield and quality. Previous studies found that mango anthracnose in China involves at least 13 species of Colletotrichum. From mango with anthracnose symptoms samples, we previously obtained 134 strains from 13 species, and 26.0% were C. fructicola, while 27.6% were C. siamense, and 31.3% were C. asianum, with a few specimens for each of the remaining species. These three main species were used in intraspecific mating tests to assess sexual reproduction. The intraspecific mating tests revealed that C. fructicola and C. siamense readily produced ascospores, while C. asianum did not. From the 595 intraspecific crosses with 35 isolates of C. fructicola, 34 crosses were considered fertile. Among these, thirty single-ascospore isolates were chosen for pathogenicity testing and genetic variation analysis (ITS and ApMat loci). The results revealed that some progeny showed higher aggressiveness than their parents, while some progeny showed lower aggressiveness. Future tests are needed to assess the genetic basis of these aggressiveness differences. The results provide a scientific basis for further research on sexual reproduction and pathogenicity of Colletotrichum, which may allow for comprehensive disease prevention and control.