Colletotrichum species associated with Camellia anthracnose in China

Abstract

Species of Camellia oleifera, Ca. sinensis and Ca. japonica represent globally-important tree germplasm resource and have significant ecological and economic value. However, they have suffered from anthracnose caused by pathogenic fungi from the genus of Colletotrichum. To determine the diversity of Colletotrichum species associated with Camellia anthracnose in China, we collected infected leaves from three major cultivation provinces. A total number of 167 fungal strains resembling Colletotrichum were obtained, 41 from Ca. oleifera, 48 from Ca. sinensis, and 78 from Ca. japonica. Comparison of morphology and phylogenetic analyses based on six loci (ACT, CAL, CHS-1, GAPDH, TUB2 and ITS) of the representative isolates revealed that they fall in four species complexes and represent 15 known and one undescribed taxa. The species complexes are Colletotrichum gloeosporioides (C. aenigma, C. alienum, C. camelliae, C. fructicola, C. gloeosporioides, C. jiangxiense, C. pandanicola, C. siamense, C. wuxiense and C. puerense described here), C. acutatum (C. fioriniae and C. nymphaeae), C. boninense (C. boninense and C. karstii) and C. orchidearum (C. clivicola and C. plurivorum). Of these, C. fructicola was the most dominant species occurring on Ca. oleifera (68.3%), Ca. sinensis (50.0%) and Ca. japonica (29.49%). Pathogenicity test results indicated that C. camelliae is the most pathogenic to the three Camellia species. This study represents the first report of C. aenigma, C. alienum, C. boninense, C. camelliae, C. clivicola, C. fioriniae, C. fructicola, C. gloeosporioides, C. jiangxinse, C. karstii, C. nymphaeae, C. pandanicola and C. wuxiense causing anthracnose on Ca. japonica and C. pandanicola on Ca. sinensis. Knowledge gained in this study enlarges our understanding of Colletotrichum species causing anthracnose on three important Camellia trees and contributes to the disease management.