Trichobotrys yunjushanensis W. J. Zhang & Z. J. Zhai, 2024

Zhang, Wen-Jing, Xu, Gui-Ping, Liu, Yu, Gao, Yang, Song, Hai-Yan, Hu, Hai-Jing, Zhou, Jian-Ping, Chen, Ming-Hui, Fan, Deng-Mei, Hu, Dian-Ming & Zhai, Zhi-Jun, 2024, Multi-gene phylogenetic analyses revealed two novel species and one new record of Trichobotrys (Pleosporales, Dictyosporiaceae) from China, MycoKeys 106, pp. 117-132 : 117-132

Trichobotrys yunjushanensis W. J. Zhang & Z. J. Zhai sp. nov.

Fig. 3

Etymology.

Referring to the collection site of the Yunjushan Mountain in Jiangxi Province, China.

Holotype.

HFJAU 10044 .

Description.

Saprobic on decaying bamboo culms. Sexual morph: Undetermined. Asexual morph: Hyphomycetous. Colonies effuse, white, yellow to olivaceous, velvety. Mycelium mostly superficial, creeping and twining, composed of septate, brown to olivaceous, branched hyphae. Conidiophores 3‒4 μm wide (x ̄ = 3.4 μm, n = 20), up to 1150 μm long, mononematous, erect, straight or flexous, septate, with fertile dichotomously branched, pale brown to olivaceous, verruculose, echinulate, thick-walled. Conidiophores branches 18–48 × 3–4 μm (x ̄ = 29.1 × 3.6 μm, n = 15), sometimes long, fertile, 0‒1 (‒ 2) - septate, verruculose, rough, pale brown. Conidiogenous cells 6–11 × 3–5 μm (x ̄ = 8.5 × 4.0 μm, n = 10), integrated, polyblastic, terminal to subterminal on fertile branches, with several denticulate conidiogenous loci, hyaline to dark brown. Conidia 7‒12 μm diam (x ̄ = 9.3 μm, n = 30), catenate, usually acrogenous or lateral, aseptate, spherical, verrucose, echinulate, sometimes guttulate, yellowish brown to dark brown when mature.

Cultural characteristics.

Conidia germinating on PDA within 24 h. Colonies incubated on PDA media at 25 ° C grow rapidly, reaching 21 mm diam after 6 days, in natural light, circular, pale on the margin, yellow at the centre, with white dense aerial mycelium; reverse yellow white to dark green. Hyphae hypline, superficial, septate but not obvious, with a layer of yellow pigment, 1.9‒3.7 μm wide.

Material examined.

China. Jiangxi Province: Jiujiang City, Yongxiu County, Yunjushan Mountain , on decaying bamboo culms submerged in a freshwater stream, alt. 672.5 m, 29.23 ° N, 115.59 ° E, 28 April 2020, G. P. Xu, Y. Liu and Z. J. Zhai, YJS 112 ( HFJAU 10044 , holotype), ex-type living culture, JAUCC 4987 = JAUCC 4988 .

Notes.

In the multi-gene phylogenetic tree, Trichobotrys yunjushanensis groups with T. effusa clade with low support (BS / PP = 43 / 0.67), but they form a monophyletic group when including T. meilingensis (Fig. 1 ). Morphologically, T. yunjushanensis is distinct from the holotype of T. effusa by its conidial size (7‒12 μm vs. 3‒4 μm) and longer conidiophores (up to 1150 μm vs. up to 200 μm) ( Petch 1924). Trichobotrys yunjushanensis is mostly similar to T. meilingensis and T. ramosa in having dichotomously branched and rough conidiophores. However, T. yunjushanensis can be easily distinguished from T. ramosa by its larger conidia (7‒12 μm vs. 3‒5 μm) ( D’Souza and Bhat 2001). Furthermore, T. yunjushanensis differs from T. meilingensis in having longer conidiophores (up to 1150 μm vs. up to 510 μm) and is phylogenetically distinct from the latter. Therefore, both morphological characters and phylogenetic analyses supported T. yunjushanensis as a new taxon within Trichobotrys .

Figures

Figure 1. Phylogenetic tree of Dictyosporiaceae inferred from the combined regions (ITS-LSU-SSU- tef 1 - α) using Maximum Likelihood (ML) analysis. The Periconia igniaria clade was used as the outgroup. PP ≥ 0.95 and BS ≥ 75 % were indicated around the branches. The new sequences generated in this study are given in red and type strains are in bold.

Figure 3. Trichobotrys yunjushanensis (HFJAU 10044, holotype) a, b colonies on bamboo culm c, d conidiophores with conidiogenous cells e, f conidiogenous cell with conidia g portion of conidiophore with fertile lateral branches h – k conidia l germinating conidium m, n culture on PDA from above (m) and reverse (n). Scale bars: 100 µm (a, b); 20 µm (c); 5 µm (d ‒ l); 25 mm (m, n).