Submersispora variabilis W. Dong, H. Zhang & K.D. Hyde, in Dong et al., Fungal Diversity 105: 440 (2020)

Index Fungorum number: IF 557917; MycoBank number: MB557917; Facesofungi number: FoF 08720; Fig. 1

Saprobic on decaying submerged wood in the river. Sexual morph Undetermined. Asexual morph Colonies on natural substrate superficial, solitary, scattered, gregarious black. Mycelium immersed in natural substrate. Conidiophores rather short, 9–26 µm long, 2–4 µm wide, semimacronematous, mononematous, cylindrical, unbranched, septate, pale brown, thin and smooth-walled. Conidiogenous cells monoblastic, holoblastic, determinate, pale brown. Conidia 47–74×50–79 µm (x̅=61×57 µm, n=10), acrogenous, solitary, globose to subglobose, sometimes ellipsoidal to oblong, muriform, multi-septate, constricted at the septa, composed of angular cells, no septa when mature, brown to dark black, smooth-walled.

Culture characteristics – Conidia germinating on PDA within 12 h at room temperature. Colonies circular, reaching 2.5 cm in 3 weeks at room temperature, mycelium superficial, flat, slightly crenate edge, bright grey in surface, dark in reverse, with radially white grey arranges at the margin.

Material examined – THAILAND, Chiang Mai, Mae Ai District, Tha Ton, Kok River, on decaying submerged wood in the river shore, 9 December 2019, S. Boonmee and N. Huanraluek, N-KR15 (MFLU 21-0063, new record), living culture, MFLUCC 21-0086.

GenBank numbers – ITS = MZ538527, LSU=MZ538561, SSU=MZ538575, RPB2=MZ567114, TEF1-α=MZ567103.

Notes – Our new collection is a typical Submersispora species, and it shares similar morphology with Submersispora variabilis in the features of conidia (Dong et al. 2020b). The multigene phylogenetic analysis showed that our isolated MFLUCC 21-0086 clustered with the type species S. variabilis with 100% MLBS, 1.00 BYPP support (Fig. 2). Therefore, we identify our collection (Fig. 1) as a new record for S. variabilis from Thailand.

Figure 1 – Submersispora variabilis (MFLU 21-0063, new record). a, b Appearance of fungal colonies on woody substrate. c–e Conidiophores with conidia. f, g Close up of conidia. h, i Culture on PDA from surface and reverse. Scale bars: c–e=20 μm, f–g=10 μm

Figure 2 – Phylogram generated from maximum likelihood analysis based on combined LSU, ITS, TEF1-α and SSU sequence data of genera in Longipedicellataceae. The tree is rooted with Bambusicola bambusae (MFLUCC 11-0614). 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 sequences are in blue