Trichoderma vadicola G.Z. Zhang, 2022

Zhang, Guang-Zhi, Yang, He-Tong, Zhang, Xin-Jian, Zhou, Fang-Yuan, Wu, Xiao-Qing, Xie, Xue-Ying, Zhao, Xiao-Yan & Zhou, Hong-Zi, 2022, Five new species of Trichoderma from moist soils in China, MycoKeys 87, pp. 133-157 : 133

Trichoderma vadicola G.Z. Zhang sp. nov.

Fig. 7

Etymology.

The specific epithet " Trichoderma vadicola ", from the noun “vadum”, reflects the ecological environment and means that the species inhabits shallow water.

Typification.

China. Shandong, 2 m (altitude), isolated from soil, 13 August 2016, G.Z. Zhang (Holotype WT 10708), Ex-type culture ACCC 39716.

Diagnosis.

Phylogenetically, Trichoderma vadicola is related to T. caerulescens in the Viride clade (Fig. 1 ), but the sequence similarity of tef1 -α and rpb2 between these species was all 95%. Morphologically, colonies of T. vadicola and T. caerulescens on PDA have similar features, such as abundant aerial hyphae, forming strands and a whitish hairy or floccose mat. However, the former Trichoderma vadicola formed no or relatively few conidia and the latter forming greyish-bluish patches around the plug. On CMD, T. caerulescens peculiar greyish-blue pigment formed after 1-2 months and conidiophores simply or slightly branched; the former had no observed diffusing pigment and conidiophores branched in a complex manner in pyramidal structure or tree-like.

Teleomorph.

Unknown.

Growth optimal at 25 °C, no grow at 35 °C on all media. Colony radius after 72 h at 25 °C 25-29 mm on PDA, 24-27 mm on CMD, 23-26 mm on MEA and 22-26 mm on SNA. Aerial mycelia abundant on PDA after 72 h at 25 °C under 12 h photoperiod, forming strands and floccose mat. Conidiation not formed or relatively few. No diffusing pigment or distinctive odour was produced. On MEA after 72 h at 25 °C under 12 h photoperiod, aerial mycelia abundant, floccose. After 7 days, mycelia covered the plate and conidia appeared, effuse, granuliform. On CMD after 72 h at 25 °C under 12 h photoperiod, aerial mycelia not observed. After 7 days, mycelia covered the plate and conidia developed near the colony margin. On SNA after 72 h at 25 °C under 12 h photoperiod, aerial mycelia not observed. After 7 days, mycelia covered the plate, aerial mycelia floccose and conidia formed, effuse. Conidiophores and branches regularly verticillate, formed a pyramidal structure, each branch terminating in a cruciate whorl of 3-5 phialides. Phialides lageniform, (8.3-)9.9-12.3(-15.1) × (2.0-)2.6-3.2(-3.4) μm (mean = 11.1 × 2.9 μm), 1.1-2.9 μm wide (mean = 1.9 μm) near the base; phialide length/width ratio (2.7-)3.2-4.6(-6.6) (mean = 3.9). Conidia subglobose or obovoidal, (3.5-)3.7-4.3(-4.8) × (3.2-)3.4-3.6(-3.8) μm (mean = 4.0 × 3.5 μm), length/width ratio 1.0-1.3 (mean = 1.1). Chlamydospores not observed.

Distribution.

China. Shandong and Yunnan Provinces.

Additional specimen examined.

China. Yunnan, Shangri-La, Pudacuo National Park, 3551 m (altitude), isolated from soil, 21 September 2016, H.T. Yang (WT 10713).

Notes.

Phylogenetically, Trichoderma vadicola is related to T. caerulescens in the Viride clade (Fig. 1 ), but the sequence similarity of tef1 -α and rpb2 between these species was all 95%, with 62 and 60 bp differences amongst 1218 and 1130 bp, respectively. Morphologically, colonies of T. vadicola and T. caerulescens on PDA have similar features, such as abundant aerial hyphae, forming strands and a whitish hairy or floccose mat. However, the former Trichoderma vadicola formed no or relatively few conidia, with the latter forming greyish-bluish patches around the plug. On CMD, T. caerulescens formed peculiar greyish-blue pigment after 1-2 months and conidiophores simply or slightly branched ( Jaklitsch et al. 2012); the former had no observed diffusing pigment and conidiophores branched in a complex manner in pyramidal structure or tree-like.

Figures

Figure 1. Phylogenetic tree, based on the Maximum Likelihood analysis of the rpb 2 (left; InL = - 5930.92) and tef 1 - α (right; InL = - 7681.95) dataset. Bootstrap values of Maximum Likelihood (left) and Maximum Parsimony (right) above 50 % are indicated at the nodes. The tree is rooted with Protocrea illinoensis TFC 9698 and P. farinose CPK 3144. New species proposed here are indicated in bold. The type strains are indicated with an asterisk (*) after the strain number. Results of the pairwise sequence similarity are illustrated on the dashed lines between the query strain and its closely-related species (arrows point to the reference strains).

Figure 7. Trichoderma vadicola A-D cultures on different media at 25 ° C (A on PDA after 10 days B on MEA, after 7 days C on CMD after 7 days D on SNA after 7 days) E-I conidiophores and phialides J conidia. Notes: E, F, H-J on MEA G on SNA A-J from WT 10708. Scale bars: 10 μm (E-J).