Pseudolophiostoma lincangense G. C. Ren & Tibpromma, 2024

Ren, Guang-Cong, Tibpromma, Saowaluck, Dong, Kai-Xuan, Gao, Chen-Xi, Zhang, Chao-Shan, Karunarathna, Samantha C., Elgorban, Abdallah M. & Gui, Heng, 2024, Unveiling fungi associated with Castanopsis woody litter in Yunnan Province, China: Insights into Pleosporales (Dothideomycetes) species, MycoKeys 108, pp. 15-45 : 15-45

Pseudolophiostoma lincangense G. C. Ren & Tibpromma sp. nov.

Fig. 5

Etymology.

The epithet refers to the location where the fungus was collected.

Holotype.

HKAS 122880 .

Description.

Saprobic on dead twigs of Castanopsis calathiformis ( Fagaceae ) in terrestrial habitat. Sexual morph: Ascomata 280–330 µm high, 230–290 μm diam. (x ̄ = 310 × 260 μm, n = 5), solitary or gregarious, immersed, papilla erumpent through host surface, subglobose, single or two locular, coriaceous, brown to dark brown, ostiolate. Ostioles 110–160 µm long, 80–90 μm diam., carbonaceous, mostly central, with crest-like opening, filled with hyaline periphyses. Peridium 10–20 µm wide, comprising 4–9 layers, composed of dark brown outer layers, inner layers comprising hyaline, flattened, angular, thick-walled cells of textura angularis. Hamathecium composed of numerous, 1–2 µm wide, flamentous, septate, branched, cellular pseudoparaphyses. Asci 80–100 × 15–20 µm (x ̄ = 94 × 16 µm, n = 20), 8 - spored, bitunicate, fissitunicate, cylindrical, with pedicel, apically rounded, with a minute ocular chamber. Ascospores 32–40 × 5–5.8 µm (x ̄ = 35 × 5.3 µm, n = 30), 1–2 - seriate, fusiform, hyaline, straight or slightly curved, 1 - septate, becoming 3 - septate when germinated, constricted at the septa, narrower towards both end cells, upper cell longer than lower cell, guttulate, smooth-walled, with mucilaginous sheath. Asexual morph: Undetermined.

Culture characteristics.

Ascospores germinated on PDA within 24 h at room temperature (25 ° C). Germ tubes produced from the apical or the second cell of ascospore. Colonies on PDA, reaching 25 mm diameter after two weeks at 20–25 ° C, mycelia superficial, circular, flat, fimbriate, undulate edge, gray with white gray at the center; reverse, dark green, pale yellow at the center.

Material examined.

China, Yunnan Province, Lincang (24 ° 5 ' 30 " N, 100 ° 5 ' 33 " E, elevation: 1557.49 m) on dead woody twigs of Castanopsis calathiformis ( Fagaceae ), 12 July 2020, G. C. Ren, LC 25 ( HKAS 122880 , holotype), ex-type living culture KUNCC 21-0606 .

Notes.

Multi-loci phylogenetic analyses based on a concatenated SSU, LSU, ITS, tef 1 - α, and rpb 2 sequence dataset show that our new collection (KUNCC 21-0606) clusters sister to strains of Pseudolophiostoma vitigenum (HH 26930 and HH 26931) with 100 % ML and 1.00 BYPP support (Fig. 1 ). Sequence comparison for the ITS region between Pseudolophiostoma lincangense (KUNCC 21-0606) and P. vitigenum (HH 26930, type) showed a 2.67 % (14 / 524 bp) base pair difference, 0.24 % (2 / 848 bp) base pair difference for LSU region, 1.97 % (17 / 863 bp) base pair difference for tef 1 - α region, but we were unable to compare rpb 2 gene of P. vitigenum as there was no sequence data. Comparatively, the morphological characterization of Pseudolophiostoma lincangense is similar to P. vitigenum in having immersed ascomata with papilla; carbonaceous ostiole with crest-like opening, and filled with hyaline periphyses; cylindrical asci with a short truncate pedicel and a minute ocular chamber; fusiform, hyaline, constricted at the septa, 1 - septate ascospores ( Thambugala et al. 2015). However, our new collection differs from P. vitigenum in having single or two locular ascomata, peridium consists of two layer cells of textura angularis, smaller asci (94 × 16 μm vs. 129.8 × 20.1 μm) and ascospores (35 × 5.3 μm vs. 38.5 × 10.5 μm), and of the upper cell of the ascospores is longer than the lower cell ( Thambugala et al. 2015). Therefore, we identify our collection as a new species from Yunnan Province, China.

Figures

Figure 1. Phylogram generated from ML analysis based on SSU, LSU, ITS, tef 1 - α, and rpb 2 sequence data representing the family Lophiostomataceae. Related sequences were obtained from Phukhamsakda et al. (2020). Bootstrap values for ML are equal to or greater than 75 %, and posterior probability values are equal to or greater than 0.95 from the BYPP analysis labelled on the nodes. Strains of the newly described species are in red, while type strains are in bold. The tree is rooted with Teichospora rubriostiolata (TR 7) and T. trabicola (C 134).

Figure 5. Pseudolophiostoma lincangense (HKAS 122880, holotype) a, b appearance of ascomata on the host surface c section of ascoma d ostiole e peridium f pseudoparaphyses g – j asci k – o ascospores p germinated ascospore q, r culture characters on PDA (q = from above, r = from below). Scale bars: 100 μm (c, d); 50 μm (e); 10 μm (f); 30 μm (g – j); 15 μm (k – p); 30 mm (q, r).