Lophiotrema lincangensis Wanas. & K.D. Hyde, sp. nov.

Index Fungorum number: IF 558584; MycoBank number: MB 558584; Facesoffungi number: FoF 09948; Fig. 1

Etymology – The specific epithet “lincangensis” refers to the Lincang City, Yunnan Province, China where the type was collected.

Holotype – HKAS 115777

Saprobic on dead twigs of Fagaceae sp. Sexual morph: Ascomata 140–180 µm high, 120–160 μm diam. (x̅=158×139 μm, n=10), solitary or gregarious, immersed to erumpent through host tissue, globose to subglobose, brown to dark brown, uni-loculate, glabrous, ostiolate. Ostiole mostly central, minute papilla. Peridium 15–30 μm wide, composed of angular, pseudoparenchymatous cells, outer layer, dark brown, thick-walled cells, inner layer, hyaline with thin-walled cells. Hamathecium composed of numerous, 1.5–2 µm wide, filamentous, septate, cellular pseudoparaphyses. Asci 50–90×6.5–9 µm (x̅=63.5×7.5 µm, n=20), 8-spored, bitunicate, fissitunicate, cylindrical to cylindric-clavate, short pedicellate, apically rounded, with a minute ocular chamber. Ascospores 16–22 × 3–4 µm (x̅=19.5×3 µm, n=30), overlapping bi-seriate, fusiform, hyaline, straight or slightly curved, one-celled when young and become inconspicuously 1-septate at maturation, the upper cell is longer than the lower cell, constricted at the septum, narrower towards both end cells, smooth-walled, guttules. Asexual morph Undetermined.

Culture characteristics – Ascospores germinating on PDA within 24 h and germ tubes arising from both ends. Colonies on PDA, slow growing, reaching 2 cm diam. after 4 weeks of incubation at room temperature, initially white becoming blackish brown at maturity, slightly effuse, radially with a smooth edge, blackish brown.

Material examined – CHINA, Yunnan, Lincang City, Linxiang, 24.883878° N 100.092519° E, on dead twigs of Fagaceae sp., 10 August 2020, GC Ren, LC21-01 (HKAS 115777, holotype), ex-type living culture could not maintain; ibid. LC21-03 (HKAS 115778), living culture could not maintain.

GenBank numbers – ITS = MZ493298, MZ493299, LSU = MZ493312, MZ493313, SSU = MZ493284, MZ493285, RPB2 = MZ508416, MZ508417 , TEF1-α=MZ508407, MZ508408.

Notes – During our investigation on the woody-based microfungi in Yunnan, two isolates were recovered from Fagaceae hosts in Lincang City. Morphological characteristics such as asci and ascospores fit well within the species concept of Lophiotrema (Fig. 1). In our phylogenetic study, these new strains clustered with L. hydei and L. mucilaginosis with 100% MLBS support (Fig. 2). Comparatively, our new collections had smaller asci and conidia than these two species (see notes of L. hydei). A nucleotide base comparison of ITS (513 bp) among our new strains, L. hydei and L. mucilaginosis reveals 23 bp (4.5%) and 24 bp (4.7%) base pair differences (Jeewon and Hyde 2016). The TEF1-α nucleotides (889 bp) comparison of the two species with our new strain reveals 29 bp (3.3%) and 24 bp (2.7%) difference respectively. The RPB2 nucleotides comparison (953 bp) of with L. mucilaginosis and our new strains reveals 54 bp (5.6%) base pair differences. Whereas L. hydei is lacking of RPB2 sequence data.

Figure 1 – Lophiotrema lincangensis (HKAS 115777, holotype). a, b Appearance of ascomata on host surface. c Longitudinal section of an ascoma. d Section of the peridium. e Pseudoparaphyses. f–i Asci. j–o Ascospores. p Germinated ascospore. q, r Culture characteristic on PDA (q=from above, r=from below). Scale bars: c=100 μm, d, f–i=20 μm, e=5 μm, j–p=10 μm, q, r=10 mm

Figure 2 – Phylogram generated from maximum likelihood analysis based on combined SSU, LSU, ITS, TEF1-α and RPB2 sequence data to indicate the newly generated strains in Lophiotremataceae. Sixty strains are included in the combined analyses which comprise a total of 4357 characters. Murilentithecium clematidis (MFLUCC 14-0561 and MFLUCC 14-0562) is selected as the outgroup taxon. The best RAxML tree with a final likelihood value of − 24211.323363 is presented. RAxML analysis yielded 1272 distinct alignment patterns and 6.17% of undetermined characters or gaps. Estimated base frequencies were as follows: A=0.246394, C=0.256619, G=0.267068, T=0.229919, with substitution rates AC=1.576531, AG=4.38051, AT=1.49611, CG=1.339907, CT=10.502267, GT=1.000000; gamma distribution shape parameter alpha=0.450773. Bootstrap support values for maximum likelihood (MLBS, left) equal to or greater than 70% is given above the nodes. Ex-type strains are in bold and newly generated sequences are in blue