Melomastia thamplaensis
Melomastia thamplaensis (J.F. Zhang, J.K. Liu, K.D. Hyde & Z.Y. Liu) W.L. Li, Maharachch. & J.K. Liu, Journal of Fungi 8(1, no. 76): 16 (2022)
Index Fungorum number: IF 552496; Facesoffungi number: FoF 02612
Saprobic on dead woody twigs of Millettia leptobotrya. Sexual morph: Ascomata 240–420 μm high × 140–440 μm diam., (x̅ = 320 × 330 μm, n = 5), immersed under the bark of the host, solitary or scattered, globose to subglobose, coriaceous to carbonaceous, black, with a central ostiole. Ostioles 175–230 × 80–130 μm (x̅ = 200 × 110 μm, n = 5), papillate, black. Peridium 30–50 μm wide, composed of dark brown outer layers and inner layers of hyaline, thick-walled cells of textura prismatica. Hamathecium 1.5–2.5 μm wide, comprising numerous, unbranching, septate, hyaline pseudoparaphyses embedded in a gelatinous matrix. Asci 140–170 × 5.8–6.4 μm (x̅ = 162 × 6 μm, n = 20), 8-spored, bitunicate, long cylindrical, straight or curved, apically rounded with an obvious apical ring, short pedicellate. Ascospores 23–27 × 4.4–5.3 μm (x̅ = 25 × 4.9 μm, n = 30), uniseriate, hyaline, fusiform with acute angular ends, 3-septate, slightly constricted at the septa, with guttules in each cell, thick and smooth-walled, without a gelatinous sheath. Asexual morph: Undetermined.
Culture characteristics: Ascospores germinating on PDA within 24 h at room temperature (25 °C). Germ tubes produced from the apical cell of the ascospore. Colonies on PDA, reaching 20 mm diameter after two weeks at 20–25 ℃, mycelia superficial, circular, flat, lobate edge, pale yellow reverse, pale yellow at the edge, dark brown at center.
Material examined: China, Yunnan Province, Xishuangbanna, on dead woody twigs of Millettia leptobotrya (Fabaceae), 15 December 2019, G.C. Ren, XS18 (HKAS 122773), living culture KUMCC 21-0671.
Known distribution: On dead branch of an unidentified plant in Thailand (Zhang et al. 2017), on dead woody twigs of Millettia leptobotrya (Fabaceae) in China.
GenBank numbers: SSU: OQ168226, LSU: OQ170875, ITS: OQ158953, tef1-α: OR613415.
Notes: Dyfrolomyces thamplaensis was introduced by Zhang et al. (2017) based on the combined phylogeny of LSU, SSU, and tef1-α sequence data and has been found from dead branches in karst landforms of China and Thailand. Li et al. (2022) synonymized Dyfrolomyces thamplaensis under Melomastia thamplaensis based on morphological characterization and phylogenetic analyses. In the present study, a multi-gene phylogeny indicates that our strain (KUMCC 21-0671) clustered together with Melomastia thamplaensis (MFLUCC 15-0635) with 99% ML bootstrap support and 1.00 BYPP value (Fig. 7). Our collection (KUMCC 21-0671) is similar to M. thamplaensis in having globose to subglobose, coriaceous to carbonaceous ascomata with papillate ostioles, long cylindrical, short-pedicellate asci with a prominent apical ring, and hyaline, fusiform, 3-septate ascospores (Zhang et al. 2017). Taking into consideration the genetic similarity and phylogenetic results, we report our saprobic fungal collection (KUMCC 21-0671) as the first record of M. thamplaensis on the woody litter of Millettia leptobotrya (Fabaceae) in China.
Figure 1. Phylogram generated from ML analysis based on SSU, LSU, ITS, tef1-α, and rpb2 sequence data representing Pleurotremataceae. Related sequences are obtained following Li et al. (2022). Forty-six strains are included in the combined analyses, which comprise 3948 characters for SSU, LSU, ITS, tef1-α, and rpb2 alignment. Anisomeridium phaeospermum (MPN539) and A. ubianum (MPN94) were used as the outgroup taxa. The best-scoring RAxML tree with a final likelihood value of -28755.342067 is presented. The matrix had 2026 distinct alignment patterns, with 32.59% of undetermined characters or gaps. Estimated base frequencies were as follows; A = 0.238390, C = 0.263023, G = 0.288210, T = 0.210377; substitution rates AC = 1.022596, AG = 2.177198, AT = 1.179336, CG = 1.031321, CT = 5.495584, GT = 1.0000. The tree topology of the ML analysis is similar to the Bayesian analysis. Bootstrap values for ML equal to or greater than 70% and BYPP values greater than 0.95 (the rounding of values to 2 decimal proportions) are labelled on the nodes. Strains of the newly described species are in blue, while type strains are in bold.
Figure 2. Melomastia thamplaensis (HKAS 122773). a Material examined. b Appearance of ascomata on the host substrate. c horizontal section of ascomata. d vertical sections of ascomata. e Section of an ascoma. f Vertical section of an ostiole. g Peridium. h Pseudoparaphyses. i–l Asci. m–p Ascospores. q Germinated ascospore. r, s Culture characters on PDA (r = from above, s = from below). Scale bars: e–f = 150 μm, g = 50 μm, h = 20 μm, i–l = 50 μm, m–q = 10 mm, r, s = 30 mm.
References
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