Parabambusicola yunnanensis L.S. Han & D.Q. Dai, in Han, Dai, Du, Wijayawardene, Promputtha, Bhat & Gao, Phytotaxa 589(3): 250 (2023)

Index Fungorum number: IF 559989;  MycoBank number: MB 559989; Facesoffungi number: FoF 12952, Fig. 1

Saprobic on submerged decayed stems of bamboo in freshwater habitats, appearing as raised, dome-shaped areas on the host surface. Sexual morph: Ascomata 175–260 µm high, 375–675 µm wide, immersed, subglobose, mostly clustered together, sometimes solitary. Peridium 25–60 µm wide, thick, 2-layered; outer layer consisting of thickwalled, multi-rows of brown, polyhedral cells of textura angularis, inner layer comprising multi-rows of pale brown to hyaline, elongated cells of textura angularis or taxtura prismatica. Hamathecium composed of numerous, filamentous, 1–2.5 µm wide, septate pseudoparaphyses. Asci 85–130 × 18–24 µm (x = 108 × 21 µm, n = 25), broadly cylindrical to cylindric-clavate, 8-spored, hyaline, bitunicate, subsessile, rounded at the apex, with clearly visible inconspicuous ocular chamber when young. Ascospores 45.5–57×6–8.5 µm (x=51×7.5 µm, n=25), overlapping 2–3-seriate, hyaline, fusiform to vermiform, slightly curved, narrower towards the lower cell, 3–(4)-septate, primary septum mostly median, smooth-walled, with sheath. Asexual morph: Undetermined.

Culture characteristics – Colonies on PDA reaching 35 mm diam. after 4 weeks at 25 °C. Colony dense, circular, flattened, surface smooth, with entire edge, velvety to floccose; from above greenish grey to dark green, paler at the edge; from below, black; produced dark brown pigmentation around colony on agar medium.

Material examined – China, Guizhou Province, Guiyang City, Changpoling Forest Park, on submerged decayed stems of bamboo in fresh water stream, 20 August 2021, Y.R. Sun, CL19 (HGUP 22-0810), living culture, GUCC 22-0821.

GenBank numbers – ITS: OR004597, LSU: OP942442, SSU: OP938586, tef1-α: OQ995148.

Notes – Parabambusicola yunnanensis was introduced by Han et al. (2023) from dead culm of bamboo in terrestrial habitats. Phylogenetically, our isolate GUCC 22-0821 clusters together with P. yunnanensis ZHKUCC 22-0290 by 100% ML and 1.00 BI support (Fig. 2). Morphologically, GUCC 22-0821 shares similar ascomata and ascospore characters with ZHKUCC 22-0290, but shorter asci (85–130 µm vs 130–180 μm). This may be caused by the different habitats. In addition, the nucleotide pairwise comparison of LSU and SSU sequences showed no base pair difference and the ITS sequence showed only two base pair differences. However, our collection was obtained from aquatic habitat. We identified our collection as Parabambusicola yunnanensis and described and illustrated here.

Figure 1 – Parabambusicola yunnanensis (HGUP 22-0810). a, b Appearance of ascomata on host substrate. c, d Section through ascoma. e–h Asci. i Peridium. j Pseudoparaphyses. k–o Ascospores. p Ascospores stained in Indian ink. Scale bars: c, d=100 µm, e–h, k–p=20 µm, i=50 µm, j=10 µm

Figure 2 –Phylogram generated from maximum likelihood analysis based on combined LSU, SSU, ITS and tef1-α sequence data. Thirty one taxa were included in the combined gene analyses, which comprised 3409 characters (LSU=838 bp, SSU=1,002 bp, ITS=699 bp, tef1-α=870 bp). The best scoring RAxML tree with a final likelihood value of − 24,627.042646 is presented. Bootstrap support for ML equal to or greater than 75% and BI equal to or greater than 0.95 are given above the nodes. Bambusicola loculate (MFLUCC 13-0856) and B. massarinia (MFLUCC 11-0389) were used as the outgroup taxa. The newly generated sequence is indicated in blue. The ex-type strains are indicated in bold