Abstract: 【Objective】 Anthracnose pathogens can infect tea leaves, causing extensive necrosis of leaves and defoliation. The objective of this study is to identify the pathogens causing anthracnose on tea plants from the major tea areas in China, and to provide an important scientific basis for tea plant disease management in the future. 【Method】 Colletotrichum species associated with anthracnose diseases of tea plants were isolated using single spore isolation and confirmed by DNA sequencing of the partial sequences of β-tubulin and rDNA-ITS region. Neighbor-Joining analysis was performed to establish the multilocus phylogeny using MEGA 6.0. The morphology of isolated strains growing on fresh PDA plates was also described. Pathogenicity of typical isolates was further verified by inoculation assay on the tea varieties of ‘Longjing 43’ and ‘Zhongcha 108’ with and without wound treatments. 【Result】 A total of 78 Colletotrichum strains were isolated from tea plants in 15 provinces (municipality, autonomous region) of China. The 2-locus (ITS, TUB2) dataset for phylogenetic analysis results showed that isolates clustered in three clades, 45 isolates clustered with the ex-type isolate of C. camelliae, 28 isolates clustered with C. fructicola, 5 isolates clustered with C. siamense and all isolates belonged to the C. gloeosporioides species complex. Moreover, the results showed that C. camelliae was the most widely distributed species in the tea regions of China, reflecting that it was the dominant Colletotrichum species on Camellia sinensis. Meanwhile, morphological analysis showed that C. camelliae colonies on PDA growth rate 11.8 mm·d^-1, aerial mycelium white, dense, cottony; setae and sclerotium were not observed; conidiophores and conidiogenous cells were not observed; conidia hyaline, smooth-walled, cylindrical with obtuse ends, sometimes narrowed at the centre or towards the base, (8-15) µm×(3-6) µm; mycelial appressoria brown, clavate, irregularly shaped, branched, (8-10.5) µm×(6.5-8) µm; conidial appressoria were not observed. C. fructicola colonies on PDA growth rate 6.76 mm·d^-1, aerial mycelium white, reverse brown in the centre, white at the margin, dense, cottony; setae and sclerotium were not observed. Conidiophores hyaline, septate, branched; conidiogenous cells hyaline, cylindrical, (7-18) μm, apex (1-2) μm diam. Conidia hyaline, cylindrical, both ends rounded, sometimes narrowed at the centre, (10-15) µm× (3-3.5) µm; mycelial appressoria dark brown, cylindrical, (6.5-8) µm×(3.5-5.5) µm; conidial appressoria dark brown or brown, rounded, (5-7) µm×(5-6.5) µm. C. siamense colonies on PDA growth rate 7.6 mm·d^-1, white, dense, cottony; setae and sclerotium were not observed; Conidiophores hyaline, septate, branched. Conidiogenous cells hyaline, cylindrical, 8-16 μm, apex 1-2 μm diam. Conidia hyaline, cylindrical, fusiformis, sometimes narrowed at the centre, (9.5-13.5) µm×(3-3.5) µm; mycelial appressoria dark brown, rounded, clavate, irregularly shaped, (5-8) µm×(3-5.5) µm. Interestingly, pathogenicity test showed that the C. camelliae could cause anthracnose lesions on the wounded leaves of ‘Longjing 43’ but not on the intact leaves; on the contrary, there were no visible disease symptoms on the ‘Zhongcha 108’ leaves. Moreover, both C. fructicola and C. siamense did not show pathogenicity on these two tea varieties. 【Conclusion】 Based on the phylogenetic analyses and the morphological observation of Colletotrichum strains isolated from tea plants from 15 provinces (municipality, autonomous region) of China, it is concluded that C. camelliae is the main causal agent of Ca. sinensis anthracnose in the major tea areas of China.

Key words: anthracnose, tea plant, molecular phylogeny, Zhongcha 108, Longjing 43, pathogenicity