Trichoderma albidum Z.F. Yu & T.T. Jing, 2023

Ye, Chuwen, Jing, Tingting, Sha, Yuru, Mo, Minghe & Yu, Zefen, 2023, Two new Trichoderma species (Hypocreales, Hypocreaceae) isolated from decaying tubers of Gastrodia elate, MycoKeys 99, pp. 187-207 : 187

Trichoderma albidum Z.F. Yu & T.T. Jing sp. nov.

Fig. 2

Etymology.

Referring to the rare white, whitish colonies on cultures media.

Description.

Sexual morph: Unknown. Asexual morph: Conidiophores straight or slightly curved, branches mostly asymmetrically arranged, also paired, sometimes at irregular intervals along the main axis, closely-spaced, often orientated toward the apex, rarely forming secondary branches. Phialides lageniform to somewhat subulate, straight or slightly curved, often with a narrow neck, often in whorls of 2-5, (6.0-) 8.3-13.5 (-15.7) × (2.9-) 3.2-4.6 (-4.8) µm, l/w ratio (1.5-) 2.0-4.0 (-4.5), (1.5-) 1.9-3.2 (-3.8) µm wide at the base, widest around the middle. Conidia ovoid to subglobose, sometimes oblong, hyaline, smooth, (3.5-) 3.7-5.3 (-6.3) × (3.2-) 3.3-4.2 (-4.8) µm (mean = 4.4 × 3.8 μm, n=50), l/w ratio 1.0-1.3 (-1.8).

Culture characteristics.

Optimum temperature for growth 25 °C. No growth at 35 °C in CMA, PDA and SNA.

Colony radius on CMA after 3 days: 9-11 mm at 25 °C, 5-6 mm after 6 days at 30 °C, covering the plate after 11 days at 25 °C. Colony white to whitish, radial, not zonate, aerial hyphae sparse, arachnoid. Conidiation start after 4 days. Chlamydospores rare. No distinct odor noted, no diffusing pigment observed.

Colony radius on PDA after 3 days: 22 mm at 25 °C, 11 mm at 30 °C, covering the plate after 7 days at 25 °C. Colony dense, pale white, finely zonate, circular, aerial hyphae abundant, fluffy. Conidiation start after 8 days, formed numerously on aerial hyphae. No distinct odor noted, no diffusing pigment observed.

Colony radius on SNA after 72 h: 14 mm at 25 °C, 4 mm at 30 °C, covering the plate after 8 days at 25 °C. Colony hyaline, indistinctly zonate, aerial hyphae scarcely degenerating. Conidiation start after 7 days. Chlamydospores rare. No distinct odor noted, no diffusing pigment observed.

Materials examined.

China. Yunnan province, Zhaotong city, Yiliang county, Xiaocaoba Town , on diseased Gastrodia elata , 25 Oct. 2021, T.T. Jing (holotype YMF 1.7530). Ibid. (culture: YMF 1.7531) .

Notes.

Phylogenetically, T. albidum is associated with T. aggressivum . In comparison, T. aggressivum grows faster on PDA (50.5-56.0 mm after 3 days at 25 °C) and SNA (58.5-62.2 mm after 3 days at 25 °C), and produces shorter and narrower phialides ((4.0-) 5.7-7.8 (-21.0) × (1.3-) 2.7-3.5 (-4.3) µm) and much smaller green conidia (3.2-3.3 × 2.8-2.9 μm) ( Samuels et al. 2002).

Figures

Figure 2. Morphology of Trichoderma albidum (YMF 1.7530) A-C cultures on PDA, 7 d; SNA, 8 d; CMA, 11 d D-H conidiophores and phialides I conidia. Scale bars: 10 μm (D-I).