Montagnula puerensis Tibpromma & T.Y. Du, 2021

Du, Tianye, Hyde, Kevin D., Mapook, Ausana, Mortimer, Peter E., Xu, Jianchu, Karunarathna, Samantha C. & Tibpromma, Saowaluck, 2021, Morphology and phylogenetic analyses reveal Montagnula puerensis sp. nov. (Didymosphaeriaceae, Pleosporales) from southwest China, Phytotaxa 514 (1), pp. 1-25 : 6-20

Montagnula puerensis Tibpromma & T.Y. Du , sp. nov. (Fig.3)

Index Fungorum number: IF558145; Facesoffungi number: FoF09620

Holotype: HKAS 111936

Etymology: named after the place Pu’er where the fungus was first discovered.

Saprobic on dead twigs of Acer sp. Sexual morph Ascomata 300–600 μm long × 230–380 μm diam. (x = 426 × 285 μm, n = 5), semi-immersed, conspicuous on host surface, solitary or scattered, globose, uniloculate to multiloculate, black, smooth-walled, with a central ostiole. Ostiole 80–130 μm long × 70–100 μm diam. (x = 120 × 90 μm, n = 5), central, filled with hyaline cells, surrounded by pale-brown stromatal tissue cells at the top of ostioles. Peridium 10–20 μm wide, thin-walled, fused with host tissues, pale brown to brown cells of textura angularis to textura prismatica. Hamathecium comprising 0.8–1.1 μm wide, numerous filamentous, branched, septate, guttulate, trabeculate pseudoparaphyses embedded in a gelatinous matrix and clearly anastomosing between the asci. Asci 70– 105 × 10–15 μm (x = 92 × 11 μm, n = 10), bitunicate, 8-spored, elongate-clavate, slightly curved, with a furcate, 85–93 μm long pedicel. Ascospores 10–20 × 4–7 μm (x = 14 × 6 μm, n = 30), biseriately arranged, ellipsoidal, 1-septate, constricted at the septum, widest at the centre, tapering towards ends, upper cell is slightly wider than the lower cell, conical both end, hyaline to yellow-brown when immature, becoming brown to dark brown when mature, guttulate, without appendages and mucilaginous sheath. Asexual morph: Undetermined.

Culture characteristics: Ascospores germinating on PDA within 24 h at room temperature (20–25 ˚C), germ tubes produced from both upper and lower cells. Colonies on PDA reaching 4 cm diam., after 4 weeks at room temperature, mycelium white to dark grey, flossy, circular with the entire edge, with filiform margin; light gray to dark brown in reverse.

FIGURE. Montagnula puerensis (HKAS 111936, holotype). a. Appearance of ascomata on the substrate. b. Section through ascomata. c–e. Immature and mature asci. f–i. Ascospores. j. Pedicel. k. Ostiole. l, m. Trabeculate pseudoparaphyses. n. Peridium . o. A germinating ascospore. p, q. Colony on PDA medium (after 20 days in culture). Scale bars: b, k = 100 μm, c–e = 50 μm, f–i, o = 10 μm, j, l–n = 20 μm.

TABLE. Comparison of gene fragments of Montagnula puerensis and five phylogenetically closely related species, different gene fragments are marked in red and the newly

generated sequences are in bold.

Remarks: comparison of LSU gene fragments showed that there were no base pair differences among closely related species. TABLE. Morphological and culture characteristics, host, and location information of Montagnula species. Host and location information of taxa are mainly from Farr & Rossman

(2021). Remarks: the symbol “—” denotes no information available.

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Material examined: China, Yunnan Province, Pu’er City, on dead twigs of Acer sp. (Sapindaceae) , 15 July 2020, S. Tibpromma, PED17 (holotype, HKAS 111936; ex-type cultures, KUMCC 20-0225; ex-isotype, KUMCC 20-0331).

Notes: In the phylogenetic analyses, five Montagnula species viz. M. chromolaenicola , M. donacina , M. graminicola , M. saikhuensis , and M. thailandica clustered with Montagnula puerensis but were well separated with moderate bootstrap support (Fig. 1). Montagnula donacina is the phylogenetically closest species to Montagnula puerensis , but they are different in morphology, M. donacina has carbonaceous ascostromata with flat bottom ( Pitt et al. 2014).

Montagnula chromolaenicola is the morphologically closest species to Montagnula puerensis , but they are different in gene fragment comparison (Table 2) of tef1-α (16 bp). Furthermore, they did not cluster in the same branch of the phylogenetic tree (Fig. 1). Meanwhile, Montagnula puerensis is different from M. graminicola because the ascospores of M. graminicola are verrucous, not constricted in the middle and surrounded by obvious sheaths ( Liu et al. 2015). Montagnula puerensis is different from M. saikhuensis because M. saikhuensis has wider (411.7 × 460.5 µm), solitary and scattered ascomata. Montagnula puerensis is different from M. thailandica because M. thailandica has globose to obpyriform ascomata; fusiform to ellipsoid ascospores that are narrower and longer than those of Montagnula puerensis .

Therefore, Montagnula puerensis , M. chromolaenicola , M. donacina , M. graminicola , M. saikhuensis and M. thailandica are different to each other.