Vikalpa dujuanhuensis H.W. Shen & Z.L. Luo, Mycology, 3 (2024)
Index Fungorum number: IF571593; MycoBank number: MB571593; Facesoffungi number: FoF15707
Saprobic on submerged decaying wood. Asexual morph: Hyphomycetous. Colonies superficial, punctiform, silver gray. Mycelium mostly immersed, composed of subhyaline, smooth, thin-walled, hyphae. Conidiophores 6.1–8 × 1.6–2.3 µm, micronematous, mononematous, septate, subglobose to subcylindrical, unbranched, subhyaline to pale brown, smooth, thin-walled, sometimes reduced to conidiogenous cells. Conidiogenous cells 2.1–5.8 × 1.4–3.4 µm (x̅ = 3.2 × 2.3 µm, n = 20), holoblastic, integrated, terminal, determinate, subglobose, subhyaline to pale brown, smooth, thin-walled. Conidia 30.5–44.2 × 10.3–13.5 µm (x̅ = 38.6 × 11.8 µm, n = 30), solitary, cheiroid, silver gray or brown, inverted cone, not complanate, composed of 2–3 rows of cells, row digitate, each row with 8–10 cells, arising from a basal cell, arms closely appressed, euseptate, slightly constricted at the septum, guttulate, with or without hyaline or multiple colors mixed together appendages at the apex. Sexual morph: Undetermined.
Culture characteristics – Conidia germinating on PDA within 12 h, and germ tubes produced from the apex. Colonies on PDA reaching 20 mm diameter after 2 weeks at room temperature. Mycelium dry, dense, colonies on the surface of PDA, with regular edges, has a spherical depression in the center, grey. Reverse brown, smooth.
Material examined – China, Yunnan Province, Wenshan Zhuang and Miao Autonomous Prefecture, Bamei Town, 7 February 2022, on submerged decaying wood, W.P. Wang, S-3271 (HKAS 131386), living culture KUNCC 23–13707; ibid., 28 February 2023, S-4349 (HKAS 131362), living culture KUNCC 23–13398.
Notes – Phylogenetic analysis showed that our new collections (KUNCC 23–13398 and KUNCC 23–13707) clustered with the type strain of Vikalpa dujuanhuensis (CGMCC 3.24268) (Fig. 8). Our new collections fit well with the description of V. dujuanhuensis in having septate, unbranched conidiophores or sometimes the conidiophores are reduced to conidiogenous cells and cheiroid, similar in size conidia (30.5–44.2 × 10.3–13.5 vs. 30–41 × 12–16 µm) consisting of three rows, not complanate, euseptate, with or without appendages at the apex (Liu et al. 2024a). The LSU, ITS, and tef1-α sequences of our new collection (KUNCC 23–13398) and the type strain (CGMCC 3.24268) showed 100.00% (1000/1000 bp), 99.46% (368/370 bp), and 99.66% (889/892 bp) similarities, respectively. Thus, our new collections were identified as V. dujuanhuensis based on morphology and phylogeny.
Figure 1 – Vikalpa dujuanhuensis (HKAS 131386). a Colonies on the substratum. b, c Conidiophores with conidiogenous cells. d, h–o conidia. e–g Conidiogenous cells with conidia. p Germinating conidium. q, r Colonies on PDA from surface and reverse. Scale bars: b, c = 5 µm, d = 30 µm, e–p = 15 µm.
Figure 2 – RAxML tree based on analysis of Dictyosporiaceae that combined ITS, LSU, and tef1-α dataset. The combined analyses include 81 strains with 2181 characters, including gaps (ITS: 498 bp, LSU: 814 bp, and tef1-α: 869 bp). Bootstrap support values for maximum likelihood (ML) greater than 75% and Bayesian posterior probabilities greater than 0.95 are indicated above branches as ML/PP. The tree is rooted with Murilentithecium clematidis (MFLUCC 14–0561 and MFLUCC 14– 6545 0562). The new collections are indicated in red. Ex-type strains are indicated with “T” after the strain number.