Distoseptispora pachyconidia
Distoseptispora pachyconidia R. Zhu & H. Zhang, in Zhang, Zhu, Qing, Yang, Li, Wang, Zhang & Ning, J. Fungi 8(no. 1063): 22 (2022)
Index Fungorum number: IF559924
Saprobic on submerged decaying wood in a freshwater stream. Anamorph: Colonies on wood effuse, hairy, dark brown, glistening, solitary or in small group. Mycelium immersed, composed of septate, pale brown to brown hyphae, smooth-walled. Conidiophores (13–)20–36(–48) × 6–8 µm (x̄ = 28 × 7 µm, n = 30), macronematous, mononematous, solitary or in groups, erect, straight or slightly flexuous, cylindrical, unbranched, 1–3-septate, brown, rounded at the apex, slightly enlarged at the basal, smooth-walled. Conidiogenous cells 6–8 × 5–6 µm (x̄ = 7 × 5 µm, n = 25), monoblastic, terminal, determinate, subcylindrical, brown, smooth-walled. Conidia (82–)137–246(–296) × (9–)13–16 µm (x̄ = 192 × 15 µm, n = 40), acrogenous, solitary, obclavate, pale brown to brown, truncate at the base, tapering towards the apex, straight or slightly curved, 14–45-distoseptate, constricted at the septa, guttulate, thick and smooth-walled. Teleomorph: Undetermined.
Culture characteristics: Conidia germinating on PDA within 12 hrs and germ tubes produced from apex and septa of conidium. Colonies growing on PDA reach 2–3 cm in one month at 26 °C in the dark, with dense, velvety, pale brown to dark brown mycelium from above; dark brown from below.
Material examined: China, Yunnan Province, Honghe Hani and Yi Autonomous Prefecture, Honghe County, 23°19′32"N, 102°20′52"E, on submerged decaying branches in a freshwater stream, 23 February 2022, Z.Q. Zhang & Q.X. Yang YJ 40–30–1 (HKAS 125824, living culture KUNCC 23–13048).
Notes: Phylogenetically, our new strain KUNCC 23–13048 grouped with the strains of Distoseptispora pachyconidia (KUMCC 21–10724 and GZCC 22–0074) with 75% ML and 0.96% PP support. Pairwise comparison of ITS, LSU, tef1-α and rpb2 sequences show negligible base pair differences. As previously reported, the conidia size and color of our new collection HKAS 125824 are significantly different from those originally described for D. pachyconidia (137–246 µm vs. 42–136 µm; pale brown to brown vs. pale-brown with a green tinge), as well as the number of conidial septa (14–45-distoseptate vs. 8–21-distoseptate) (Yang et al. 2018; Shen et al. 2021; Ma et al. 2022). Our new collection is also slightly different from the collection described by Ma et al. (2022), especially the number of conidial septa (14–45-distoseptate vs. up to 38-distoseptate) (Ma et al. 2022). However, based on slight differences in molecular data, this collection was not sufficient to qualify as a new species, and therefore, identify this collection as D. pachyconidia, which was first discovered in the Red River Basin of Yunnan.
Figure 1. Maximum likelihood (ML) tree is based on combined LSU, ITS, tef1-α and rpb2 sequence data. Bootstrap support values with a ML greater than 65% and Bayesian posterior probabilities (PP) greater than 0.95 are given above the nodes, shown as “ML/PP”. The tree is rooted to Aquapteridospora fusiformis (MFLUCC 18–1606) and A.lignicola (MFLUCC 15–0377). New species are indicated in blue and type strains are in bold.
Figure 2. Distoseptispora pachyconidia (HKAS 125824) a, b colonies on woody substrates c conidiophores e conidiophores with conidia d conidiogenous cells f, g conidia h germinated conidium i culture on PDA. Scale bars: 20 μm (c, d); 60 μm (e–h).
References
Shen H-W, Bao D-F, Boonmee S, Lu Y-Z, Su X-J, Li Y-X, Luo Z-L (2024) Diversity of Distoseptispora (Distoseptisporaceae) taxa on submerged decaying wood from the Red River in Yunnan, China. MycoKeys 102: 1–28. https://doi.org/10.3897/mycokeys.102.116096
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