Identification of <i>Colletotrichum</i> Species Associated with Anthracnose Disease of Strawberry in Sichuan Province, China

Abstract

Strawberry anthracnose, caused by <i>Colletotrichum</i> species, is a major fungal disease threatening the strawberry industry in Sichuan Province of southwestern China. However, research on identification of <i>Colletotrichum</i> species associated with strawberry anthracnose in Sichuan remains scarce. In this study, 73 representative <i>Colletotrichum</i> strains were isolated from diseased leaves, stolons, petioles, and crowns of 11 major strawberry-planting localities in Sichuan Province. Based on morphological characteristics and multiloci phylogenetic analysis, the <i>Colletotrichum</i> strains were identified as three distinct species: <i>Colletotrichum fructicola</i> (53 strains, 72.60%), <i>Colletotrichum siamense</i> (17 strains, 23.29%), and <i>Colletotrichum gloeosporioides sensu stricto</i> (3 strains, 4.11%). Among them, <i>C. fructicola</i> was the most ubiquitous and dominant species, whereas <i>C. gloeosporioides sensu stricto</i> was restricted to Chongzhou. Importantly, our pathogenicity tests showed that <i>C. fructicola</i> and <i>C. siamense</i> can infect both leaves and stolons, whereas <i>C. gloeosporioides sensu stricto</i> was only pathogenic to leaves. Interestingly, although the sexual stage of <i>C. siamense</i> was not observed in this study, it still exhibited the strongest virulence to strawberry compared with <i>C. gloeosporioides sensu stricto</i> and <i>C. fructicola</i>. This is the first study to characterize <i>Colletotrichum</i> species causing strawberry anthracnose and evaluate their pathogenicity in Sichuan Province of southwestern China, which will provide a better strategy for accurate diagnosis and management of anthracnose disease in strawberry.