Kirschsteiniothelia dendryphioides X. Tang, K. D. Hyde, Jayaward. & J. C. Kang, 2024

Tang, Xia, Jeewon, Rajesh, Jayawardena, Ruvishika S., Gomdola, Deecksha, Lu, Yong-Zhong, Xu, Rong-Ju, Alrefaei, Abdulwahed Fahad, Alotibi, Fatimah, Hyde, Kevin D. & Kang, Ji-Chuan, 2024, Additions to the genus Kirschsteiniothelia (Dothideomycetes); Three novel species and a new host record, based on morphology and phylogeny, MycoKeys 110, pp. 35-66 : 35-66

Kirschsteiniothelia dendryphioides X. Tang, K. D. Hyde, Jayaward. & J. C. Kang , sp. nov.

Figs 4 , 5

Etymology.

The specific epithet “ dendryphioides ” is derived from the resemblance to the dendryphiopsis-like features.

Holotype.

HKAS 136930.

Description.

Saprobic on an unidentified decaying wood. Sexual morph: Undetermined. Asexual morph: Colonies on the natural substrate superficial, effuse, scattered, hairy, black, glistening. Mycelium partly immersed, on the substrate, pale brown to dark brown. Conidiophores 179–467 × 4.5–8 μm (x ̄ = 318.2 × 6.1 μm, n = 10), macronematous, mononematous, erect, subscorpioid branched, straight or flexuous, cylindrical, septate, smooth, brown to dark brown, becoming paler towards the apex. Conidiogenous cells 9–19 × 4–8 μm (x ̄ = 13.3 × 6.1 μm, n = 30), monotretic, terminal or intercalary, integrated, sometimes percurrent, cylindrical, doliiform, mostly discrete, determinate, smooth, pale brown to brown, both ends appearing darker, with new cells developing from the apical or subapical part of the subtending cells. Conidia 30–55 × 9–13.5 μm (x ̄ = 40 × 11.1 µm, n = 30), solitary, acrogenous, cylindrical, oblong and occasionally clavate, smooth, guttulate, 2–4 - septate, slightly or deeply constricted and darker at the septa, brown, rounded at the apex and sometimes truncate at the base, exhibiting obtuse ends.

Culture characteristics.

Conidia germinating on PDA within 24 hours. Colonies circular, characterised by dense, flat, spreading and fluffy growth, with an entire margin. The surface displayed a dark brown hue, while the reverse colonies exhibited a circular shape with an entire margin, also appearing dark brown.

Material examined.

China • Yunnan Province, Lushui City, Sanhe Village, Gaoligong Mountain , saprobic on decaying wood in a freshwater stream, 5 May 2021, Rong-ju Xu, XS 17 (HKAS 136930, holotype), ex-type living culture, KUNCC 10431; ibid. • saprobic on submerged decaying wood in freshwater habitats, 22 August 2021, Rong-ju Xu, SYC- 05 (HKAS 135651, paratype), living culture, KUNCC 10499.

Notes.

Kirschsteiniothelia dendryphioides exhibits dendryphiopsis-like characteristics and shares similar morphologies with other Kirschsteiniothelia species. However, K. dendryphioides differs from other species in the size of its conidiophores, conidiogenous cells and conidia. Kirschsteiniothelia dendryphioides is distinct from K. atra in having larger conidiophores (179–467 × 4.5–8 μm, L / W ratio = 52.2 vs. 148–228 µm × 6–8 μm, L / W ratio = 27), shorter conidiogenous cells (9–19 × 4–8 μm, L / W ratio = 2.2 vs. 25–33 µm × 5–7 μm, L / W ratio = 4.8) and smaller conidia (30–55 × 9–13.5 μm, L / W ratio = 3.6 vs. 54–63 × 14–18 μm, L / W ratio = 3.4).

The establishment of Kirschsteiniothelia dendryphioides as a new species is further supported by molecular data. Based on our phylogenetic analyses, K. dendryphioides strains (KUNCC 10431 and KUNCC 10499) form a subclade sister to the strains of Kirschsteiniothelia atra (CBS 109.53, DEN, MFLUCC 15-0424, MFLUCC 16-1104 and S- 783) with 83 % ML and 0.99 PP support (Fig. 1 ). The comparison of the nucleotides between the sequences of K. dendryphioides and K. atra (MFLUCC 16-1104) shows a difference of 1.9 % (9 / 481 bp) across ITS and 2.4 % (11 / 458 bp) across SSU, but no difference was observed across LSU (777 bp), excluding gaps. Based on these findings, we introduce Kirschsteiniothelia dendryphioides as a novel species, following guidelines outlined in Jeewon and Hyde (2016) and Maharachchikumbura et al. (2021). We were unable to compare the nucleotide differences across LSU and SSU of KUNCC 10499 as it lacks sequence data for these loci.

Figures

Figure 1. Phylogram of Kirschsteiniothelia taxa, based on the RAxML analysis of the combined ITS, LSU and SSU rDNA sequence dataset. Bootstrap support values for Maximum Likelihood (ML) equal to or greater than 75 % and Bayesian posterior probabilities (PP) equal to or greater than 0.95 are shown above the nodes. The tree is rooted with Strigula guangxiensis (HMAS- L 0138040) and S. nemathora (MPN 72). Newly-generated strains are denoted in red and type strains are indicated with a superscript “ T ”.

Figure 4. Kirschsteiniothelia dendryphioides (HKAS 136930, holotype) a, b colonies on natural substrate c, d conidiophores, conidiogenous cells bearing conidia e – g conidiogenous cells bearing conidia h – o conidia p upper surface view of culture q lower surface view of culture; Scale bars: 100 μm (c, d); 50 μm (e); 20 μm (f – o).

Figure 5. Kirschsteiniothelia dendryphioides (HKAS 135651, paratype) a, b colonies on natural substrate c, d conidiophores, conidiogenous cells bearing conidia e – g conidiogenous cells bearing conidia h – l conidia m upper surface view of culture n lower surface view of culture. Scale bars: 100 μm (c, d); 20 μm (e – l).