Wicklowia fusiformispora Boonmee, Huanraluek & K.D. Hyde, sp. nov.
Index Fungorum number: IF 558541; MycoBank number: MB 558541; Facesoffungi number: FoF 09954; Fig. 1
Etymology – The specific epithet “fusiformispora” refers to the fusiform shape of ascospores.
Holotype – MFLU 21-0068
Saprobic on decaying submerged wood in the river. Sexual morph Ascomata 212–244 × 225–274 μm (x̅=231×253 μm), immersed, erumpent when mature, ellipsoid on the host surface, scattered, gregarious, subglobose, uni-loculate, dark brown, ostiolate. Peridium 32–51 μm wide, thick-walled, composed of light brown to dark brown of pseudoparenchymatous cells of textura angularis. Hamathecium comprising 1–3 μm wide, numerous, cylindrical, filiform, branched, septate, hyaline pseudoparaphyses. Asci 78–151×21–30 μm (x̅=115×30 μm, n=10), 8-spored, bitunicate, fissitunicate, cylindrical-clavate, apically thickened and rounded, with an ocular chamber when immature, sessile or short pedicellate. Ascospores 32–41×9–19 μm (x̅=36×12 μm, n=20), 2–3-seriate overlapping, fusiform to cylindrical-ellipsoid, with rounded ends, slightly inequilateral, asymmetrical, slightly curved, hyaline, 1-septate, constricted at the septum, guttulate when immature, surrounded by a thin mucilaginous sheath, smooth-walled. Asexual morph Undetermined.
Culture characteristics – Ascospores germinated on PDA within 12 h at room temperature. Colonies on MEA, reaching 15 mm diam. in 4 weeks at room temperature. Mycelium superficial, hairy, radiating outwards, effuse with wavy to fimbriate edge, dark brown.
Material examined – THAILAND, Chiang Mai Province, Mae Ai, Tha Ton, Kok River, on decaying submerged wood in the river shore, 9 December 2019, S. Boonmee, N-KR1 (MFLU 21-0068, holotype), ex-type living culture, MFLUCC 21-0091.
GenBank numbers – ITS=MZ538533, LSU=MZ538567, SSU=MZ538576, TEF1-α=MZ567108.
Notes – Wicklowia fusiformispora shares common characters with other described species in Wicklowia, but it differs from all the other species in terms of details regarding features including of shape and size of ascomata, asci and ascospores (Raja et al. 2010; Boonmee et al. 2019; Calabon et al. 2020a). Phylogenetic analysis based on a combined LSU and SSU sequence dataset indicates that W. fusiformispora clustered with W. phuketensis with 97% MLBS, 1.00 BYPP support (Fig. 2). However, Wicklowia fusiformispora is distinct from W. phuketensis by its uni-loculate ascomata and has smaller asci (78–151 × 21–30 μm vs. 86–288×22–32 µm) and ascospores (32–41×9–19 μm vs. 34–43×9–12 µm) (Calabon et al. 2020a, b). A comparison of LSU sequences indicates that W. fusiformispora differs from W. aquatica in 27/850 bp (3.17%), W. phuketensis in 10/850 bp (1.17%), and W. submersa 18/850 (2.11%). Sequence data of the ITS region of W. aquatica, W. phuketensis and W. submersa are not available in the GenBank for the comparison. We therefore, identify W. fusiformispora as a new species which collected from Kok River in northern Thailand (Fig. 1).
Figure 1 – Wicklowia fusiformispora (MFLU 21-0068, holotype). a, b Appearance of ascomata on decaying submerged wood. c, d Cross sections of ascomata. e Section of peridium. f Pseudoparaphyses. g–k Asci. l–o Ascospores. p Ascospore stained in Nigrosine reagent. q Germinated ascospore. r, s Culture on MEA from above and below. Scale bars: c, d=200 µm, e–k, q=20 µm, l–p=10 µm
Figure 2 – Maximum likelihood phylogenetic tree based on a combined LSU and SSU sequence data of Wicklowia taxa (Wicklowiaceae) and related families. The tree is rooted with Delitschia chaetomioides (SMH 3253.2) and D. winteri (CBS 225.62). Bootstrap support values for maximum likelihood (MLBS, left) equal to or greater than 50% 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