Colletotrichum xishanense Q.T. Wang, S.Y. Zhao & C.L. Hou

Zhao, Shi-Yi, Wang, Qiu-Tong, Guo, Mei-Jun & Hou, Cheng-Lin, 2024, Colletotrichum xishanense as a new etiological anthracnose agent on Fagopyrum gracilipes in Yunnan Province, China, Phytotaxa 644 (3), pp. 201-210 : 206-207

Colletotrichum xishanense Q.T. Wang, S.Y. Zhao & C.L. Hou , sp. nov.

MycoBank MB852865

Etymology: Referring to the location Xishan Forest Park where the host plant was collected.

Typification: CHINA. YUNAN PROVINCE: On leaves of Fagopyrum gracilipes, Aug. 2019 , Q.T. Wang, S.Y. Zhao & C.L. Hou. (Holotype, CAF8000205 ). Ex-type culture CFCC 70552 = CNUCC 453-2-3-1 .

Description: Sexual morph not observed. Asexual morph on OA. Conidiomata absent, conidiophores formed directly on hyphae. Vegetative hyphae hyaline to medium brown, smooth-walled, septate, branched. Setae not observed. Conidiophores solitary, hyaline, septate, usually reduced to conidiogenous cells. Conidiogenous cells hyaline, aseptate, smooth-walled, ampulliform, 14.5–20 × 2.5–3.5 μm. Conidia hyaline, aseptate, smooth-walled, straight, cylindrical, one end obtuse round and another end truncate, 13–17 × 4.5–6 μm (av. ± SD = 15.1 ± 1.1 × 5.1 ± 0.3 μm), L/W ratio = 3.0. Appressoria solitary or in loose groups, brown to dark brown, clavate or arrowhead -shaped, margin undulate, 11.0–18.0 × 4.0–7.5 μm (av. ± SD = 14.4 ± 1.9 × 6.1 ± 0.9 μm), L/W ratio = 2.4.

Culture characteristics: Colonies on PDA 61–62 mm diam in 7 days, margin entire or undulate, surface grayish orange, aerial mycelium dense, reverse olivaceous, white edge.

Other specimen examined: CHINA. YUNAN PROVINCE: On leaves of Fagopyrum gracilipes, Aug. 2019 , Q.T. Wang, S.Y. Zhao & C.L. Hou, living culture CNUCC 453-2-3-2.

Notes: Colletotrichum xishanense formed a branch with high support values on the 6-loci phylogenetic tree (MP = 100%, BI = 1.00), while clustered with C. cycadis in a branch with lower support values. Morphologically, there is a difference in the size of conidia and appressoria between them. The conidial length of C. cycadis is 9.5–13.5 × 3–4 μm and the length of appressoria is 4.5–8 × 2–5.5 μm. The conidial length of C. xishanense is 13–17 × 4.5–6 μm and length of appressoria is 11.0–18.0 × 4.0–7.5 μm. On the 2-loci phylogenetic tree, C. xishanense formed an independent branch with high support values (MP = 100%, BI = 1.00). A BLASTn search of the sequence of strain CNUCC 453-2- 3- 1 in NCBI GenBank revealed low sequence similarity with act, apmat, chs-1, gapdh, gs, tub2 of other species. The most similar to its act, apmat, chs-1, gapdh, gs, tub2 sequences were C. camellia (97.59%), C. arecicola (95.07%), C. kahawae (98.54%), C. kahawae (97.96%), C. camelliae (97.38%) and C. camelliae (98.33%). Therefore, based on morphology combined with multigene phylogenetic analysis, this branch was designated as a new species in this study.