Palmiascoma qujingense
Palmiascoma qujingense Monkai & Phookamsak, in Monkai, Wanasinghe, Jeewon, Promputtha & Phookamsak, Mycol. Progr. 20: 727 (2021)
Index Fungorum number: IF 556132; Facesofungi number: FoF 09505
Saprobic on dead woody twigs of Myristica yunnanensis. Sexual morph: Ascomata 280–400 μm high, 200–300 μm wide (x̅ = 322.1 × 258.4 μm, n = 10), clustered or scattered, immersed to semi-immersed, slightly erumpent, conical to subglobose or irregular in shape, glabrous, black, short-papillate, ostiolate. Peridium 15−40 μm wide, thin to thick-walled, of unequal thickness, slightly thick at sides, comprising dark brown cells of textura angularis. Hamathecium of dense, 1.5–3 μm wide, hyaline, septate, branched, cellular pseudoparaphyses, anastomosing above the asci, embedded in a mucilaginous matrix. Asci 60−80 × 9−10 μm (x̅ = 69.6 ± 6 × 9.6 ± 0.8 μm, n = 20), 8-spored, bitunicate, fissitunicate, cylindric-clavate, short pedicellate, apically rounded, with a minute ocular chamber. Ascospores 12−16 × 4.5−5.5 μm (x̅ = 14.1 ± 1.1 × 4.6 ± 0.5 μm, n = 25), overlapping 1–2-seriate, clavate to ellipsoidal, slightly curved, pale yellowish when young, becoming brown to dark brown at maturity, 1-septate, slightly constricted at the septum, upper part slightly wider, rough-walled, echinulate, lacking a mucilaginous sheath (Monkai et al. 2021). Asexual morph: Coelomycetous. Conidiomata 90–250 μm high × 80–150 μm diam., (x̅ = 170 × 130 μm, n = 5), scattered, immersed, coriaceous, globose to subglobose, brown to dark brown. Conidiomatal wall 15–45 μm thick, 3–4 layered, composed of brown outer layers and hyaline inner layers of thin walled cells of textura angularis. Conidiophores reduced to conidiogenous cells. Conidiogenous cells 4–6 × 3–4 μm (x̅ = 4.8 × 3.1 μm, n = 10), enteroblastic, phialidic, determinate, discrete, oblong to ampulliform, hyaline, smooth walled, arising from the stratum. Conidia 4–6 × 2–3 μm (x̅ = 4.6 × 2.4 μm, n = 30), straight, initially hyaline, becoming brown at maturity, subglobose to oval, one celled, rounded ends, thick walled, guttulate.
Culture Characters: Conidia germinating on PDA within 24 h at room temperature (25 °C).
Germ tubes produced from the apex. Colonies on PDA, reaching 50 mm diameter after two weeks at 20–25 ℃, mycelia superficial, circular, sparse mycelia, zonate, white at the margin, atrovirens at the center.
Material examined: China, Yunnan Province, Xishuangbanna, on dead woody twigs of Myristica yunnanensis (Myristicaceae), 15 December 2019, G.C. Ren, XS36 (HKAS 122889), living culture KUMCC 21 0678.
Known distribution: On dead twigs of Fagaceae sp. in China (Monkai et al. 2021), branch blight pathogen of Juglans regia (Juglandaceae) in China (Wang et al. 2022), on dead woody twigs of Myristica yunnanensis (Myristicaceae) in China (This study).
GenBank numbers: LSU: OQ170845, ITS: OQ158925, tef1-α: OR613426.
Notes – Phylogenetic analyses show that our strain KUMCC 21-0678 grouped within Palmiascoma qujingense with 100% ML bootstrap support and 1.00 BYPP value. The type strain of P. qujingense (KUMCC 19-0201) was only described from the sexual morph (Monkai et al. 2021), and later Wang et al. (2022) introduced both sexual and asexual morphs of P. qujingense. A BLASTn search of the ITS sequence, our strain showed 100% similarity to P. qujingense and the closest match of the tef1-α sequence with 98.5% similarity was P. qujingense (CAUCC 21-0013). Palmiascoma qujingense (CAUCC 21-0013) was identified as a disease of Juglans regia (walnut species) (Wang et al. 2022). The morphology of the new isolate is similar to the description of P. qujingense (CAUCC 21-0013) provided by Wang et al. (2022). Therefore, we identified our collections as asexual morphs of P. qujingense based on morphological characterization and phylogenetic analyses and introduced P. qujingense as a saprobic fungi from China.
Figure 1. Phylogram generated from ML analysis based on SSU, LSU, ITS, tef1-α, and rpb2 sequence data, representing Bambusicolaceae. Related sequences are obtained following Phukhamsakda et al. (2022). Forty-two strains are included in the combined analyses, which comprise 4040 characters for SSU, LSU, ITS, tef1-α, and rpb2 alignment. Murilentithecium clematidis (MFLUCC 14 0561) and M. lonicerae (MFLUCC 18 0675) were used as the outgroup taxa. The best-scoring RAxML tree with a final likelihood value of 17373.628804 is presented. The matrix had 939 distinct alignment patterns, with 17.41% of undetermined characters or gaps. Estimated base frequencies were as follows; A = 0.242291, C = 0.257231, G = 0.271517, T = 0.228961; substitution rates AC = 1.354747, AG = 2.926058, AT = 1.006416, CG = 0.994544, CT = 6.807971, 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 3. Palmiascoma qujingense (HKAS 122889). a Material examined. b, c Conidiomata on the natural wood surface. d Sections through conidiomata. e Conidiomata wall. f, g Conidiogenous cells and developing conidia. h Conidia. i, j Culture characters on PDA. Scale bars: d = 100 μm, e = 30 μm, f–h = 10 μm, i, j = 30 mm.
References
- 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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