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

Fig. 3

Etymology.

Referring to the luteous, orange to amber, variable coloration of the colonies on cultures media.

Description.

Sexual morph: Unknown. Asexual morph: Conidiophores straight or curved, asymmetry, sparsely branches, cylindrical mostly sterile to the apex. Often with a main axis, frequently tips sterile, disposed, relatively distant distribution at right angles to the axis or slightly oriented towards the conidiophore terminus, often solitary, not or rebranched once. Phialide lageniform to subulate, sometimes cylindrical, often with a narrow neck, discrete or integrated, solitary or in whorls of 2-3 (-4), (9.5-) 9.8-14.6 (-15.4) × (3.2-) 3.5-5.4 (-6.7) µm, l/w ratio (1.9-) 2.1-4.3 (-4.6), 2.2-3.4 µm wide at the base, widest around the middle. Conidia ellipsoidal to oblong, sometimes obovate, green, smooth, (4.3-) 4.7-7.4 (-8.6) × (2.7-) 3.0-4.1 (-4.3) µm (mean = 6.1 × 3.5 μm, n=50), l/w ratio (1.0-) 1.4-2.0 (-2.2).

Culture characteristics.

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

Colony radius on CMA after 72 h: 20-22 mm at 25 °C, 14-15 mm at 30 °C, covering the plate after 8 days at 25 °C. Colony hyaline, indistinctly zonate, aerial hyphae nearly lacking. Conidiation starting after 8 days, formed on aerial hyphae. Chlamydospores common, subglobose to globose, smooth, terminal and intercalary, 5.3-13.4 × 5.0-11.3 µm. No distinct odor noted, yellow pigment noted.

Colony radius on PDA after 72 h: 30-32 mm at 25 °C, 27-29 mm at 30 °C, cover the plate after 6 days at 25 °C. Colony dense, aerial hyphae abundant, margin slightly lobed, forming numerous small yellow pigment droplets on the surface in the mature phase. Conidiation started after 8 days, formed on aerial hyphae. Chlamydospores abundant, subglobose to globose, smooth, terminal and intercalary, 5.5-10.6 × 5.3-10.1 µm. No distinct odor noted, yellow to brownish pigment diffusing into the agar.

Colony radius on SNA after 72 h: 18-22 mm at 25 °C, 17-19 mm at 30 °C, covering the plate after 8 days at 25 °C. Colony hyaline, not zonate, aerial hyphae sparse, relatively abundant at margin, arachnoid. Conidiation formed after 7 days, formed on aerial hyphae. Chlamydospores common, subglobose to globose, smooth, terminal and intercalary, 5.8-12.3 × 5.7-11.4 µm. No distinct odor noted, yellow pigment noted.

Materials examined.

China. Yunnan province, Zhaotong city, Yiliang county, Xiaocaoba Town , on diseased Gastrodia elata , 25 Oct 2021, T.T. Jing (holotype YMF 1.7533). Ibid. (cultures: YMF 1.7532 and YMF 1.7534) .

Notes.

Phylogenetically, T. variegatum is closely related to T. hunanense in the Spirale clade. T. hunanense can be easily distinguished by much shorter conidia ((3.6-) 4.2-5.6 (-7.5) µm) and not producing chlamydospore ( Chen and Zhuang 2017a). Moreover, T. hunanense grows faster on PDA (46-47 mm after 3 days at 25 °C) and SNA (27-28 mm after 3 days at 25 °C) and forms green pustules in culture compared with T. variegatum ( Chen and Zhuang 2017a).

Figures

Figure 3. Morphology of Trichoderma variegatum (YMF 1.7533) A-D cultures on PDA, 8 d; SNA, 9 d; CMA, 9 d; PDA, 4 d E, F, H, I conidiophores and phialides G conidia. Scale bars: 10 μm (E-I).