Homortomyces xianggelilaensis
Homortomyces xianggelilaensis G.C. Ren & K.D. Hyde (2024)
Index Fungorum number: IF901347; Facesoffungi Number: FoF13883
Holotype: MFLU 122769
Etymology: The species epithet “xianggelila” refers to the location where the specimen was collected.
Saprobic on dead woody twigs of Quercus serrata. Sexual morph: Ascomata 230–350 μm high × 300–320 μm diam., (x̅ = 315 × 310 μm, n = 6), scattered, solitary, immersed to partially erumpent through the host tissues, black, globose to subglobose, unilocular, ostiolate. Peridium 15–30 μm wide, comprising 2–3 layers of brown, thick walled cells of textura angularis. Hamathecium comprising 2–3.5 μm wide, scarce, filiform, hyaline, septate, pseudoparaphyses embedded in a gelatinous matrix. Asci 85–110 × 27–35 μm (x̅ = 97 × 30 μm, n = 25), mostly 6–8 spored, bitunicate, cylindric clavate to broadly clavate, straight or slightly curved, with short truncate pedicel, apically rounded. Ascospores 20–26 × 10–13 μm (x̅ = 22.9 × 11.8 μm, n = 30), biseriate, oblong or fabiform, pale brown to light brown when immature, becoming brown to dark brown when mature, 1 septate, smooth walled, with rounded ends. Asexual morph: Undetermined.
Culture characteristics: Ascospores germinating on PDA within 24 h at room temperature (25 °C). Germ tubes produced from the basal and apical cells of ascospore. Colonies on PDA, slow growing, reaching 15 mm diameter after two weeks at 20–25 ℃, mycelia medium dense, superficial, raised, circular, surface rough with crenate edge, pale yellow, reverse dark grey, pale yellow at margin.
Material examined: China, Yunnan Province, Diqing, Xianggelila, on dead woody twigs of Quercus serrate (Fagaceae), 21 August 2019, G.C. Ren, T904 (HKAS 122769, holotype), ex type living culture KUMCC 21 0656. ibid., T910 (HKAS 122770, isotype), ex-isotype KUMCC 21
0658.
GenBank numbers: KUMCC 21-0656: LSU: OQ170852, ITS: PP408196; KUMCC 21-
0658: LSU: OQ170853, ITS: PP408197.
Notes: Homortomyces xianggelilaensis is introduced as a new species based on its distinct morphology and phylogenetic analyses of the combined LSU and ITS dataset. Two of our strains (KUMCC 21 0656 and KUMCC 21 0658) clustered sister to H. combreti with 92% ML bootstrap support and 1.00 BYPP value. Our species can be distinguished from H. tamaricis in having cylindric clavate to broadly clavate, 6–8 spored asci with oblong or fabiform, 1 septate ascospores, while H. tamaricis has cylindrical, 2–6 spored asci with fusiform, 3 septate ascospores (Thambugala et al. 2017). Homortomyces combreti is only known from their asexual morphs and was associated with leaf spots on Combretum erythrophyllum (Crous et al. 2012). As we did not obtain the asexual morph from Homortomyces xianggelilaensis, the morphological comparison between our new species and Homortomyces combreti is not possible. A nucleotide pairwise comparison showed that Homortomyces xianggelilaensis differs from H. combreti in 24/832 bp of LSU (2.59%, without gaps). However, based on the phylogenetic distinctiveness, Homortomyces xianggelilaensis is introduced as a new species.
Figure 1. Phylogram generated from ML analysis based on LSU and ITS sequence data. Related sequences are obtained following Wijayawardene et al. (2014b) and BLAST search results in GenBank. Twenty-one strains are included in the combined analyses which comprise 1375 characters for LSU and ITS alignment. Helicomyces roseus (CBS 28351) was used as the outgroup taxon. The best-scoring RAxML tree with a final likelihood value of -5336.843287 is presented. The matrix had 381 distinct alignment patterns, with 14.32% of undetermined characters or gaps. Estimated base frequencies were as follows; A = 0.237833, C = 0.239976, G = 0.293129, T = 0.229062; substitution rates AC = 1.383847, AG = 2.064248, AT = 1.659808, CG = 0.843518, CT = 5.572533, 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 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. Homortomyces xianggelilaensis (HKAS 122769, holotype). a Material examined. b Appearance of ascomata on the host substrate. c Section of an ascoma. d Peridium. e Pseudoparaphyses. f–j Asci. k–o Ascospores. p Germinated ascospore. q, r Culture characters on PDA (q = from above, r = from below). Scale bars: c = 100 μm, d, f–j = 50 μm, e = 30 μm, k–p = 20 μm, q, r = 30 mm.
- Ren GC, Jayasiri SC, Tibpromma S, De Farias ARG, et al. (2024) Saprobic ascomycetes associated with woody litter from the Greater Mekong Subregion (Southwestern China and Northern Thailand). Mycosphere 15(1), 954–1082, Doi 10.5943/mycosphere/15/1/8
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