Montagnula thailandica Mapook & K.D. Hyde, in Mapook et al., Fungal Diversity 101: 35 (2020)

Index Fungorum number: IF557299; MycoBank number: MB557299; Facesofungi number: FoF 07792; Fig. 1

Saprobic on dead stems. Sexual morph Ascomata (333–)463–514 × 264–505 µm, immersed to erumpent, scattered, gregarious to grouped, uni-loculate, globose to obpyriform, coriaceous, brown to dark brown, with papillate ostiole in the centre. Peridium (44–)60–81 µm wide, comprising several layers of thick-walled, brown to dark brown cells of textura angularis. Hamathecium comprising 1–2 µm wide, cylindrical to filiform, septate, branched, hyaline pseudoparaphyses. Asci 66–121×6–11 µm (x̅=82×10 µm, n=20), 8-spored, bitunicate, fissitunicate, elongate-clavate, slightly curved, long pedicel. Ascospores 14–17×4–6 µm (x̅=15 × 5 µm, n=20), overlapping 1–2-seriate, broadly fusiform to ellipsoid, hyaline to pale brown when immature, becoming brown to dark brown when mature, 1-septate, constricted at the septum, slightly wider upper cell and tapering towards ends, slightly curved, with 2–4-guttulate, smooth-walled. Asexual morph Undetermined.

Culture characteristics – Ascospores germinating on PDA within 24 h at room temperature and germ tubes produced from both cells. Colonies on PDA circular, mycelium velvety with moderately fluffy, filamentous at margin, cultures grey with white from the centre of the colony on surface, darkened from reverse.

Material examined – THAILAND, Chiang Rai Province, Muang, Mae Yao, on dead stems of unidentified host, 23 September 2019, N. Huanraluek, MY04 (MFLU 21-0052, new record), living culture, MFLUCC 21-0075.

GenBank numbers – ITS=MZ538515, LSU=MZ538549, TEF1-α=MZ567092.

Notes –The new collection shares cluster and a phylogenetic affinity to the ex-type strain Montagnula thailandica (MFLUCC 17-1508) based on a combined LSU, ITS, SSU and TEF1-α sequence analysis but with low statistical support (Fig. 2). Comparisons of ITS, TEF1-α and LSU sequences show that our isolate MFLUCC 21-0075 differs from the ex-type strain M. thailandica (MFLUCC 17-1508) in 1/550 bp (0.18%) of ITS and 7/907 bp (0.77%) of TEF1-α, while LSU has no base pair difference. In addition, our collection MFLUCC 21-0075 shares identical characters with M. thailandica (MFLUCC 17-1508) isolated by Mapook et al. (2020) from dead stems of Chromolaena odorata from Chiang Mai, Thailand. This is a second report of this species on dead stems as a new record from Thailand (Fig. 1).

Figure 1 –  Montagnula thailandica (MFLU 21-0052, new record). a, b Appearance of ascomata on woody substrate. c Section of ascoma through ostiole. d Section of ostiole. e Peridium. f Pseudoparaphyses. g–k Immature and mature asci. l–n Ascospores. o Germinated ascospore. p, q Culture on PDA from surface and reverse. Scale bars: c=200 µm, d, e=100 µm, f–k=50 µm, l–n=10 µm, o=20 µm

Figure 2 – Phylogram generated from maximum likelihood analysis based on combined LSU, ITS, SSU and TEF1-α sequence data of Montagnula taxa. The tree is rooted with Pleospora herbarum (MFLUCC 13-0344). Bootstrap support values for maximum likelihood (MLBS, left) equal to or greater than 70% is given above the nodes. Bayesian posterior probabilities (BYPP, right) equal to or greater than 0.95 are given above the nodes. Ex-type strains are in bold and newly generated sequence is in blue