Trichoderma subalni Y.B. Zhang & W.Y. Zhuang, 2018

Zhang, Yu-Bo & Zhuang, Wen-Ying, 2018, New species of Trichoderma in the Harzianum, Longibrachiatum and Viride clades, Phytotaxa 379 (2), pp. 131-142 : 139

Trichoderma subalni Y.B. Zhang & W.Y. Zhuang , sp. nov. ( Fig. 4 )

Fungal names: FN 570574

Etymology:— The specific epithet refers to the morphological similarity to T. alni .

Type:— CHINA. Tibet: Bomê, Gangxiang Nature Reserve, alt. 2700 m, on rotten wood, 19 Sep 2016, Y.B. Zhang, Z.Q. Zeng, Z.H. Yu, H.D. Zheng, K. Chen & X.C. Wang 11017 (holotype HMAS 275683, ex-type culture HMAS 247267).

Stromata solitary or aggregated in small groups, pulvinate, outline irregular, ca. 1–3 mm in diam., 1 mm high. Surface yellowish brown to reddish brown, becoming dark in 3% KOH. Ostioles inconspicuous. In section, cortical tissue of textura angularis, 12–25 μm thick, cells luteofulvous, thick-walled, (2–)2.9–8(–11) × 1.5–6 μm (n = 30); subcortical tissue of textura angularis, cells slightly orange, thin-walled, 6–10 × 4–6 μm; subperithecial tissue of textura epidermoidea, cells hyaline, thin-walled, 9–33 × 4.5–16 μm; tissue at the base of textura angularis mixed with hyphae, cells hyaline to light orange, thin-walled, 6–18 × 4–10 μm, hyphae hyaline to light orange, thin-walled, 2.8–9 μm wide. Perithecia subglobose or flask-shaped, 191–243 × 88–176 μm; peridium light orange to orange-yellow, 3.5–12 μm thick at flanks, 5–11 μm thick at the base. Ostioles 50–77 μm high, 19–41 μm wide at the apex. Asci subcylindrical, 76–100 × 4–5 μm, with a stipe 9–17 μm long. Ascospores green, verruculose, dimorphic, distal cells globose or oblong, 3–5 × 3–4.5 μm, L/W 1–1.4(–1.5); proximal cells subglobose to ellipsoid, 3–5 × 2.5–3.5 μm, L/ W 1.1 –1.7(–1.9).

Colony on CMD 41–48 mm in radius after 72 h at 25 °C, covering the plate after 5 days. Colony circular, semitranslucent, aerial hyphae loosely distributed. Conidiation noted after 4 days on aerial hyphae and in pustules. No diffusing pigment produced; no distinct odor detected.

Colony on PDA 27–43 mm in radius after 72 h at 25 °C, covering the plate after 7 days. Colony outline irregular, with margin lobed, zonate, aerial hyphae abundant, downy. Conidiation noted after 2 days on aerial hyphae near the plug. Yellowish brown pigment produced; no distinct odor detected.

Colony on SNA 26–47 mm in radius after 72 h at 25 °C, covering the plate after 7 days. Colony outline irregular, hyaline, margin lobed, inconspicuously zonate, aerial hyphae sparsely disposed. Conidiation noted after 4 days on aerial hyphae. Conidiophores trichoderma-like, often re-branching once. Phialides solitary or commonly divergent in whorls of 2–4, subulate, lageniform or ampulliform, 7–15 × 2–3.5 μm, L/W 2–5.3, 1.5–3 μm wide at the base. Conidia green, surface smooth, globose, oblong or ellipsoid, 2.5–5 × 2–3 μm, L/W 1–1.6. No diffusing pigment produced; no distinct odor detected.

Additional specimen examined:— CHINA. Tibet: Bomê, Gangxiang Nature Reserve, alt. 2700 m, on rotten wood, 19 Sep 2016, Y.B. Zhang, Z.Q. Zeng, Z.H. Yu, H.D. Zheng, K. Chen & X.C. Wang 11020 ( HMAS 275684, culture HMAS 247268).

Notes:— Trichoderma subalni is morphologically similar to T. alni in stroma appearance, anatomical structure and size of ascospores. But T. alni differs in somewhat loose conidiophore branching pattern, slightly larger ascospores [proximal cells (3.5–)4.5–6(–7.2) × (2.7–)3–3.5(–4) μm], and sequence data ( Jaklitsch et al. 2008). Phylogenetically, T. subalni is closely related to T. zayuense , although the latter grows faster, produces chlamydospores on PDA and SNA, and possesses wider phialides (3.1–4.2 × 2.8–3.8 μm) ( Chen & Zhuang 2017a). There are 30–40 bp divergences in TEF 1 sequence between T. subalni and T. zayuense .

Figures

FIGURE 4. Trichoderma subalni. a–c Stromata on natural substrate. d Perithecium in section. e Cortical and subcortical tissues in section. f Subperithecial tissue and stroma base in section. g Ascus. h–j Cultures after 6 days at 25 °C (h CMD, i PDA, j SNA). k–o Conidiophores (SNA, 4 days). p Conidia (SNA, 4 days). Bars: a–c, h–j = 10 mm, d, f = 50 μm, e, k–n = 20 μm, g, o, p = 10 μm.