Dematiomelanomma yunnanense Y. Gao, Wanas., H. Gui & K.D. Hyde, 2023

Gao, Ying, Zhong, Tingfang, Bhat, Jayarama D., Gomes de Farias, Antonio Roberto, Dawoud, Turki M., Hyde, Kevin D., Xiong, Weiqiang, Li, Yunju, Gui, Heng, Yang, Xuefei, Wu, Shixi & Wanasinghe, Dhanushka N., 2023, Pleomorphic Dematiomelanomma yunnanense gen. et sp. nov. (Ascomycota, Melanommataceae) from grassland vegetation in Yunnan, China, MycoKeys 98, pp. 273-297 : 273

Dematiomelanomma yunnanense Y. Gao, Wanas., H. Gui & K.D. Hyde sp. nov.

Figs 2 , 3

Etymology.

The specific epithet “yunnanense” refers to Yunnan Province, where the holotype was collected.

Holotype.

HKAS 124666.

Description.

Saprobic on decaying stalk of Rubus parvifolius and Hypericum monogynum . Sexual morph: Ascomata 360-440 μm high × 425-500 μm diam. (x̄ = 396 × 460 μm, n = 10), mostly gregarious, black, globose to subglobose, superficial, ostiolate. Ostiole central, minute papillate, filled with hyaline cells. Peridium 30-60 μm thick (x̄ = 47 μm, n = 30), irregularly multi-layered, comprising brown to black cells of textura angularis, with inner layer composed of flattened, hyaline cells of textura angularis. Hamathecium composed of 1-2.5 μm (x̄ = 1.7 μm, n = 30) wide, septate, hyaline, branched pseudoparaphyses. Asci (165-)180-223(-232) × (18-)19-25(-26) μm (x̄ = 200 × 22 μm, n = 20, SD = 22 × 3.3), eight-spored, bitunicate, fissitunicate, cylindrical, pedicellate, apically rounded, thick-walled at apex, with a minute ocular chamber. Ascospores (27-)29-33(-34) × (9-)10.2-12.6(-14.5) μm (x̄ = 30.8 × 11.4 μm, n = 30, SD = 2 × 1.2), muriform, with 3-7 transverse septa, and 1-3 vertical septa, with transverse septum appearing first, then vertical septa gradually emerge, mostly ellipsoidal or fusiform, rounded at both ends, initially hyaline, becoming dark brown at maturity, constricted at septa, smooth-walled, with a mucilaginous sheath. Asexual morph: Conidiomata 240-360 μm high × 185-245 µm diam (x̄ = 279 × 214 μm, n = 10), pycnidial, solitary or gregarious, superficial, obpyriform, dark brown to black, ostiolate. Ostiole 122-134 μm high × 57-62 µm wide (x̄ = 125 × 60 μm, n = 5), single, centric, circular, with hyaline periphyses, ostiolate, e single, circular, centrally papillate with or without periphyses. Conidiomatal wall multi-layered, 30-50 µm wide (x̄ = 34 μm, n = 30), composed of brown cells of textura angularis, with inner layer comprising hyaline cells. Macroconidiogenous cells (5-)5.5-8.7(-9.7) × (4-)5.8-8(-9.5) μm (x̄ = 7 × 7 μm, SD = 1.6 × 1.3 μm, n = 20), enteroblastic, annellidic, integrated, indeterminate, doliiform, smooth-walled, hyaline, arising from the inner wall cells of pycnidial wall. Macroconidia (30-)32.5-37.5(-39) × (8-)10-12(-14) μm (x̄ = 35 × 11 μm, SD = 2.5 × 1.2, n = 30), medium brown to dark brown, ellipsoidal to fusiform, phragmosporous to muriform, with 6-9 transverse septa, and 1-2 longitudinal septa, 1-2 oblique septa, curved to straight.

Culture characteristics.

Ascospores germinated on PDA within 20 hours, and germ tube initially produced from the 2 ends of the ascospores. Colonies on PDA reaching 25 mm in 3 weeks at room temperature (25-27 °C), irregular, center is slightly raised, panniform, mycelium grows on the surface of PDA, brown from the above, brown in the center gradually becoming yellow towards the edges from the below. Conidia germinating on PDA within 24 hours. Colonies on PDA reaching 20 mm in 2 weeks at 25-27 °C, circular, slightly raised, floccose, white from the above and yellowish from the center and below, smooth with filamentous edge. Mycelium 2-3 μm broad, (x̄ = 2.5 μm, n = 30), septate, hyaline, branched and sporulated after 24 weeks. Asexual morph on PDA (Fig. 4 ): Conidiomata 60-155 μm high × 62-145 µm diam (x̄ = 123 × 119 μm, n = 10), pycnidial, gregarious, immersed to superficial, globose to subglobose, dark brown to black, ostiolate, with clear gelatinous substance at the top. Peridium thin, composed of brown cells of textura angularis to globulosa. Microconidiogenous cells (4.5-)6.5-8.6(-9) × (2.5-)3.5-6(-6.5) μm (x̄ = 7.5 × 4.7 μm, SD = 1.1 × 1.2 μm, n = 25), hyaline, integrated, enteroblastic, percurrently annellidic, ampulliform to subcylindrical. Microconidia (2.5-)2.7-3.6(-5) × (1.6-)1.8-2.2(-2.5) μm (x̄ = 3.2 × 2 μm, SD = 0.44 × 0.2 μm, n = 30), hyaline, aseptate, round to oblong or ellipsoidal, with small guttules.

Material examined.

China, Yunnan Province, Zhaotong city, Daguan County Grassland (27°44'23"N, 103°47'59"E), on decaying stalk of Hypericum monogynum , 21 August 2021, ZG7FB (HKAS 124666, holotype, asexual morph), ex-type, KUNCC 23-12728. ibid., ZG7 (HKAS 127122, isotype), ex-isotype, KUNCC 22-12677 . China, Yunnan Province, Zhaotong city, Daguan County Grassland (27°44'23"N, 103°47'59"E), on decaying stalk of Rubus parvifolius , 21 August 2021, Ying Gao, ZG 11FB (HKAS 124667, sexual morph), living culture, KUNCC 23-12730. ibid., ZG11 (HKAS 127123), living culture, CGMCC 3.23744 .

Note.

Four strains of Dematiomelanomma clustered in Melanommataceae as a strongly supported monophyletic clade (Fig. 1 ) in both ML and BI of a concatenated SSU, LSU, ITS, tef 1-α and rpb 2 dataset. Two specimens belong to the sexual morph (KUNCC23-12730, CGMCC 3.23744) collected on decaying stalks of Rubus parvifolius and two asexual morphic coelomycetous fungi (KUNCC 23-12728, KUNCC 22-12677) were collected on the decaying stem of Hypericum monogynum from grassland in Zhaotong, Yunnan. There was no significant difference between the morphological characteristics of these sexual morphic specimens or asexual morphic specimens and DNA-based sequence comparisons of these collections. Therefore, we introduce them as different collections of Dematiomelanomma yunnanense sp. nov.

Figures

Figure 1. Maximum likelihood (ML) tree resulting from a RAxML analysis of the combined (SSU, LSU, ITS, tef 1 - α and rpb 2) alignment of the analyzed genera in Melanommataceae. The tree is rooted with Cyclothyriella rubronotata (CBS 121892 and CBS 141486). Bootstrap support values for ML equal to or greater than 70 % and the Bayesian posterior probabilities equal to or higher than 0.95 PP are indicated above the nodes as ML / PP. Branches with an asterisk (*) indicate ML = 100 % and PP = 1.00. Ex-type, ex-isotype, ex-paratype or ex-epitype strains are in bold, and the new isolate is indicated in blue.

Figure 2. Sexual morph of Dematiomelanomma yunnanense (HKAS 124667) on decaying stalk of Rubus parvifolius L. a, b ascomata in face view c vertical section of the ascoma d pseudoparaphyses e an ascospore in Indian Ink to show a sheath f-h ascospores i-l Asci m germinating ascospore n, o surface and reverse of colony on PDA. Scale bars: 100 μm (c); 10 μm (d-h); 50 μm (i-l).

Figure 3. Asexual morph of Dematiomelanomma yunnanense on a dead stalk of Hypericum monogynum L. (HKAS 124666, holotype) a, b conidiomata in face view c, d vertical section of conidiomata e vertical section of the base of the pulvinate-structure f conidioma wall g conidiogenous cells arising from the wall and developing conidia h vertical section through ostiole i developing stages of conidia j-p conidia q geminating conidia r cultures on PDA from above s cultures on PDA from reverse. Scale bars: 100 μm (c, d); 50 μm (e); 30 μm (f); 10 μm (g); 20 μm (h); 30 μm (i); 15 μm (j-l); 10 μm (m-p); 20 μm (q).

Figure 4. Asexual morph of Dematiomelanomma yunnanense from the culture (CGMCC 3.23744) on PDA a, b colony of the sexual morphic stage after 24 weeks on PDA (b from the bottom) c-e conidiomata f conidioma wall g mycelium h conidiogenous cells arising from the wall and developing conidia i conidia. Scale bars: 100 μm (e); 15 μm (f); 30 μm (g); 5 μm (h); 15 μm (i).