Colletotrichum species associated with cultivated citrus in China

There have been considerable advances in the understanding of species concepts in the genus Colletotrichum. This has lead to the need to carry out fresh surveys of Colletotrichum species associated with important hosts. Colletotrichum species are associated with Citrus plants as saprobes, important pre-harvest and post-harvest pathogens, as well as endophytes. In this study, a total of 312 Colletotrichum strains were isolated from leaves, shoots and fruits of cultivated Citrus and Fortunella species with or without disease symptoms across the main citrus production areas in China. The morphology of all strains were studied and multilocus (ACT, TUB2, CAL, GAPDH, GS, ITS) phylogeny established. Strains were from four important species complexes of Colletotrichum, namely C. gloeosporioides species complex, C. boninense species complex, C. acutatum species complex and a final group including C. truncatum, which was rare on Citrus species. The species belonging to the C. gloeosporioides species complex comprised C. gloeosporioides and C. fructicola, the C. boninense complex comprised C. karstii and a new species C. citricola and the C. acutatum complex included a new species, C. citri. The ability of strains to cause anthracnose on citrus fruits was tested by inoculation and strains of Colletotrichum gloeosporioides, C. fructicola and C. truncatum were pathogenic.