Trichoderma thailandense Suwannar., T. Gateta, S. Boonlue & J. Kumla, 2024

Gateta, Thanawan, Suwannarach, Nakarin, Kumla, Jaturong, Nuangmek, Wipornpan, Seemakram, Wasan, Srisapoomi, Totsaporn & Boonlue, Sophon, 2024, Trichoderma thailandense sp. nov. (Hypocreales, Hypocreaceae), a new species from Thailand, Phytotaxa 669 (3), pp. 233-246 : 238-240

Trichoderma thailandense Suwannar., T. Gateta, S. Boonlue & J. Kumla , sp. nov. Figure 2 .

MycoBank number: MB854462

Etymology:— ‘ thailandense ’ referring to Thailand where samples containing the new fungus was collected.

Type:— THAILAND. Chiang Mai Province, Muang District, Chiang Mai University , 18°48´16´´N 98°57´07´´E, elevation 333 m, on pileus surface of oyster mushroom ( Pleurotus sp. ), 19 August 2020, N. Suwannarach & J. Kumla, Holotype CMUB40053 , preserved in a metabolically inactive state; Ex-type culture SDBR-CMU496 .

Gene sequences (from type):—PP774228 (ITS), PP783308 (rpb2), and PP783309 (tef1-α).

Fungicolous on pileus surface of oyster mushroom ( Pleurotus sp. ). Sexual morph Unknown. Asexual morph Conidiophore pyramidal was formed on the aerial mycelium the main axis and with side branches something at right angles. The main axis with side branches commonly terminating verticillate, whorl of up to three phialides, hyaline. Phialides commonly ampulliform, sometimes flask-shaped and inflated at the base, hyaline, 4.4–8.7 × 1.4–4.3 μm, average ± SD = 7.3±0.1.5 × 2.9±0.5 μm (n =50). Conidia globose to subglobose, one-celled, initially hyaline, and they turn green, 2.0–3.6 × 1.8–3.4 μm, average ± SD = 2.8±0.37 × 2.6±0.40 μm (n =50). Chlamydospores abundant, common single sometimes terminal and intercalary, globose to subglobose, 4.5–10.6 × 4.2–10.5 μm (n =50).

Culture characteristics:—Optimum temperature for growth is 25°C on PDA, SNA, MEA, and CMA. Colonies diameter after 72 h at 25, 30, and 35°C on the following agar: PDA 63–64, 59–61, and 45– 44 mm; SNA 54–55, 52–54, and 39–41 mm; MEA 61–62, 55–57, and 33–34 mm, and CMA 54–55, 43–45, and 22–23 mm, respectively. Colonies on PDA were abundant white thick aerial mycelium, white-light green, regularly circular, distinctly zonate. Colonies on SNA were flat with entire edges, distinctly zonate; mycelium loose, especially at the margin, aerial hyphae short. Colonies on MEA were well-defined, white-green to bright green, regularly circular, distinctly zonate; mycelium dense and radial, relatively rare in the middle, abundant in the margin. Colonies on CMD were flat aerial mycelia sparely developed. Colony hyaline, irregularly circular, indistinctly zonate; mycelium loose. No diffusing pigment observed and no producing odor on PDA, SNA, MEA, and CMA. Conidiation aggregated in sporadic near the colony margin, white. Conidial production was noted after 3 days, starting around the inoculum.

Distribution:—Known only from Thailand.

Additional specimens examined:— THAILAND. Khao Kho District, Phetchabun Province, 16°49’45.6”N, 100° 58’ 27.6”E, isolated from upland black rice in farmer rice field, 21 July 2021, T. Gateta, KKU-PBMP43 (living culture). Gene sequence ITS (LC738616), rpb2 (OR488621), and tef1-α (OR488623).

Notes:—Morphologically, the colony characteristics of T. thailandense on PDA and SNA at 25 °C similar to T. botryosum M.C.H. Rodríguez, H.C. Evans & R.W. Barreto (2021: 12) ( Rodríguez et al. 2021). However, T. botryosum can be easily distinguished from T. thailandense by its smaller conidial size (1.4–3.3 × 1.6–2.8 μm) and globose to ellipsoidal chlamydospores ( Rodríguez et al. 2021). Based on similarity of rpb2 and tef1-α sequences, T. thailandense KKU-PBMP 43 and CMUB 40053 (type species) showed values of 97.44% to 97.55% for rpb2 sequence and 96.26% to 95.73% for tef1-α sequence to T. botryosum E623 (type species). Therefore, T. thailandense and T. botryosum can be considered as a different species. Furthermore, the phylogenetic analyses of the combined ITS, rpb2, and tef1-α sequences indicated that T. thailandense has a distinguished lineage from T. botryosum and previously known Trichoderma species ( Figure 1 ).

Figures

FIGURE 1. Phylogenetic tree derived from maximum likelihood analysis of 74 fungal strains of the combined ITS, rpb2, and tef1-α genes. Trichoderma parestonicum CBS 120636 and T. ceramicum CBS 114576 were used as the outgroup. The numbers above branches represent maximum likelihood bootstrap percentages (left) and Bayesian posterior probabilities (right). Bootstrap values ≥ 75% and Bayesian posterior probabilities ≥ 0.90 are shown. The scale bar represents the expected number of nucleotide substitutions per site. Sequences of fungal strains obtained in this study are in red. Type species are in bold.

FIGURE 2. Trichoderma thailandense (SDBR-CMU496, Ex-type). Colony inoculated at 25 °C for 72 h A. PDA; B. CMD; C. SNA; D. MEA; E, F. conidiation pustules on SNA after 72 h; G–I. conidiophores, phialide and conidia; J, K. chlamydospores and L, M. conidia. Scale bars:A–D = 10 mm, G–M = 10 μm