Trichoderma bashania Feihu Wang & C. L. Yang, 2025

Wang, Feihu, Xu, Xiulan, Liu, Feng, Xiang, Shasha, Li, Xinyue, Liu, Yinggao & Yang, Chunlin, 2025, Four new species of Trichoderma (Hypocreaceae, Hypocreales) discovered in the staple food bamboo of pandas, MycoKeys 124, pp. 227-248 : 227-248

Trichoderma bashania Feihu Wang & C. L. Yang sp. nov.

Fig. 3

Etymology.

Named after the genus of the host plant from which the holotype was collected, Bashania faberi.

Holotype.

SICAU 25-0179 .

Habitat.

On the culm of Bashania faberi.

Description.

Sexual morph: Stromata scattered, sparsely spreading, growing on the side adjacent to the ground surface, base narrow, pulvinate or discoidal. Color of stromata pale orange-yellow when fresh, brown when mature, with a diameter of 1–4 mm and a thickness of 1–2 mm. Immature, surface of stromata finely velvety, upon maturity, tuberculate with fine granules or slightly rugose. Outline circular, oblong or irregularly lobed. Surface smooth, tubercular or rugose, when young finely velvety. Ascomata 120–190 × 80–140 μm (x – = 145 × 115 μm, n = 30), numerous, with 10–30 ascomata present, and are sub-globose or pear-shaped in form. Ostioles flush with the surface, 18–30 μm wide at the apex, 26–38 μm high (n = 20). Peridium 13–24 μm (n = 60) thick at the base, composed of hyaline textura globosa. Asci 60–90 × 3.5–6 μm (x – = 85 × 4.5 μm, n = 30), short stipe, containing 13 - ascospores, apex not thickened, hyaline, cylindrical. Ascospores 3–6 × 2.5–4.5 μm (x – = 4.5 × 3 μm, n = 50), hyaline, containing 1–2 oil droplets, single-celled, non-septate, and sub-globose. Asexual morph: Conidiophores simple structure, with 1–3 solitary phialides borne at the tips of lateral branches. Phialides measure 4–18 × 1.5–3 μm (x – = 14 × 2.5 μm, n = 20), mostly lageniform, less commonly subfusiform, and typically do not thicken near the base. Conidia vary in size and shape, measuring 2.5–4.5 × 2–4 μm (x – = 4 × 3 μm, n = 50), oval, ellipsoid, and hyaline, smooth-surfaced.

Material examined.

China • Sichuan Province, Chengdu City, Dujiangyan , Primitive Forest of Bashania faberi ( 31°12'8.63"N, 103°42'49.96"E, Alt. 1212 m), 11 December 2023, Feihu Wang, WFH 202312013, ( SICAU 25-0179 , holotype), ex-type culture SICAUCC 25-0151 . ibid. WFH 202312013 B ( SICAU 25-0180 , paratype), living culture SICAUCC 25-0152 .

GenBank accession numbers.

SICAUCC 25-0151 ( ITS: PV 789471; tef 1 - α: PV 828324; rpb 2: PV 828316); SICAUCC 25-0152 ( ITS: PV 789472; tef 1 - α: PV 828325; rpb 2: PV 828317).

Culture characters.

This fungal strain exhibits optimal growth on all tested media at 30 ° C, whereas growth is restricted or completely inhibited at 35 ° C. On PDA, at 30 ° C, the colony slowly covers a 60 - mm Petri dish within 10 days, displaying a grayish-white color with a radial growth pattern and fluffy texture. Conidiation initiates after 15 days, producing numerous white conidia that aggregate into irregularly margined patches. On SNA, growth is the slowest among the three media; at 30 ° C, the colony reaches a radius of 50 mm after 10 days, remaining white with a radial pattern and sparse hyphae. Conidiation begins 15 days post-inoculation, forming white, irregularly margined conidial patches composed of aggregated conidia. No odor or pigment diffusion is detected. On MEA, at 30 ° C, the colony rapidly covers the entire 60 - mm dish within 7 days, featuring a well-defined border, radial growth, and creamy-white mycelium with dense, abundant aerial hyphae. No distinct odor or diffusing pigment is observed.

Notes.

Phylogenetically, Trichoderma bashania ( SICAU 25-0179 ) and ( SICAU 25-0179 ) formed a distinct clade and is related to T. dorothopsis (HZA 5 E) in the Koningii clade, but the similarities of rpb 2 and tef 1 - α between these two species were only 95.3 % and 98.3 %, respectively. From a morphological perspective, only the asexual stage of T. dorothopsis has been described, and there are differences in conidia between these two Trichoderma species. The conidia of T. bashania are elliptical or ovoid, whereas those of T. dorothopsis are globose to subglobose ( Tomah et al. 2020). Phylogenetic analysis indicates that the new taxon T. bashania ( SICAU 25-0179 ) is closely related to T. dorothopsis (HZA 5 E) (Fig. 1 ). However, our strain exhibits nucleotide differences from T. dorothopsis in the rpb 2 region amounting to 4.7 % (39 / 822, 3 gaps), 1.7 % (13 / 753, 0 gap) differences in tef 1 - α. The PHI test revealed no significant recombination event between our strain and the closely related taxa (Φw = 1.00) (Fig. 2 ). These differences also support the classification of T. bashania as a distinct species separate from T. dorothopsis .

Figures

Figure 1. Phylogram generated from maximum likelihood analysis based on combined ITS, tef 1 - α and rpb 2 sequence data of Trichoderma (koningii species complex) taxa. The species determined in this study are indicated in bold red. Bootstrap values (BS) from maximum likelihood (MLBS, left) higher than 70 BS and Bayesian posterior probabilities (BYPP, right) greater than 0.90 are given at the nodes. Hyphens (-) represent support values less than 70 MLBS / 0.90 BYPP. The ex-type strains are in T.

Figure 2. The PHI test results for Trichoderma bashania, T. fargesia, T. mianyangensis, T. yaanensis, and closely related species were obtained using both LogDet transformation and splits decomposition methods. The PHI test did not find any statistically significant recombination (Φw = 1) in the data set. The new strains are represented in red and bold. “ T ” represents the type strain.

Figure 3. Trichoderma bashania (SICAU 25-0179, holotype). a. Appearance of ascomata on dead host; b. Stromata; c. Ascomatal tissue in section; d. Peridium; e – h. Asci; i. Ascospores; j. Culture on PDA (15 days at 30 ° C); k. Cultures on SNA (15 days at 30 ° C); l. Cultures on MEA (15 days at 30 ° C); m – o. Conidiophores and phialides (PDA 30 days at 30 ° C); p. Conidia (PDA 30 days at 30 ° C). Scale bars: 500 µm (b); 200 µm (c); 10 µm (d – h, p); 5 µm (i, m – o).