Didymella yunnanensis Y. Wang, Y. Tu, X. Chen, H. Jiang, H. Ren, Q. Lu, C. Wei & W. Lv, 2024

Wang, Yuchun, Tu, Yiyi, Chen, Xueling, Jiang, Hong, Ren, Hengze, Lu, Qinhua, Wei, Chaoling & Lv, Wuyun, 2024, Didymellaceae species associated with tea plant (Camellia sinensis) in China, MycoKeys 105, pp. 217-251 : 217-251

Didymella yunnanensis Y. Wang, Y. Tu, X. Chen, H. Jiang, H. Ren, Q. Lu, C. Wei & W. Lv sp. nov.

Fig. 5

Etymology.

Named after the location where it was collected, Yunnan Province.

Description.

Sexual morph: undetermined. Asexual morph: Pycnidia smooth, subglobose to ellipsoidal, hyaline. Conidia ellipsoidal to subcylindrical, pale, smooth- and thin-walled, abundant, generated from pycnidia, aseptate, 4–6.5 × 1.8–2.6 µm (av. = 5.2 ± 0.5 × 2.3 ± 0.2 µm, n = 30). Mycelia sparsely branched from subapical hyphal compartments (lateral branching), septate, hyaline.

Culture characteristics.

Colonies on PDA have scarce aerial mycelium reaching 24–27 mm diam. after being cultured for 7 days at 28 ° C in the dark, margin regular, olive in the centre, white edges; black on the reverse, white edges. Pycnidia and conidia produced on the colony surface after being cultured for 14 days at 28 ° C in the dark. Colonies on OA reaching 18–21 mm diam. after 7 days at 28 ° C in the dark, margin regular, aerial mycelium flat, black in the centre, white edges; olive on the reverse, white edges.

Materials examined.

China, Yunnan Province, Puer City, Jingdong Yizu Autonomous County, from healthy leaves of C. sinensis cv. Longjing 43, 16 Jun 2020, Y. C. Wang, Holotype HMAS 352387 , culture ex-type CGMCC 3.24241 = YCW 1909 .

Notes.

Didymella yunnanensis is closely related to D. prosopidis with high statistical support (88 % / 0.92, ML / PP, Fig. 2 ). Didymella yunnanensis has 85 bp differences in LSU locus from D. prosopidis . In addition, D. yunnanensis can be distinguished from D. prosopidis by the morphological features of conidia and the conidia size of D. yunnanensis (4–6.5 × 1.8–2.6 µm) is smaller than that of D. prosopidis (5–7 × 2.5–3.5 µm). In the present study, Didymella yunnanensis was isolated from healthy tea plant leaves.

Figures

Figure 2. Phylogenetic tree generated by Maximum Likelihood analysis, based on the combined ITS, LSU, RPB 2 and TUB 2 dataset of Didymella species. Bootstrap support values above 50 % and Bayesian posterior values above 0.75 are shown at each node (ML / PP). Pleiochaeta setosa CBS 118.25 / CBS 496.63 and Coniothyrium palmarum CBS 400.71 are used as outgroups. Ex-type strains are emphasised in bold.

Figure 5. Didymella yunnanensis CGMCC 3.24241 (YCW 1909) A, B colony on PDA (front and reverse) C, D colony on OA (front and reverse) E myceli F pycnidia forming on PDA G conidia. Scale bars: 10 μm (E – G).