Lophiotrema mucilaginosum

Lophiotrema mucilaginosis M. Raza & L. Cai Fungal Diversity 32,(2019)

Index Fungorum number: IF555333; Facesoffungi number: FoF04941

Saprobic on dead twigs of Dipterocarpus gracilis (Dipterocarpaceae). Sexual morph: Ascomata 190–240 μm high, 150–190 μm diameter (x̅= 221 × 174 μm, n = 5), solitary or gregarious, immersed, subglobose or obpyriform, brown to dark brown, ostiolate. Ostiole 46–60 μm long, 23–30 μm diameter, carbonaceous, mostly central, minute papilla, with crest-like opening, filled with hyaline periphysate. Peridium 8–13, composed of fattened, angular, pseudoparenchymatous cells, dark brown, thick-walled cells. Hamathecium composed of numerous, 1.5–2.5 μm wide, flamentous, septate, branched, cellular pseudoparaphyses. Asci 70–90 × 8–8.7 μm (x̅=79 × 8.4 μm, n = 20), 8-spored, bitunicate, fissitunicate, cylindrical, with a short truncate pedicel, apically rounded, with a minute ocular chamber. Ascospores 19–22.5 × 3.5–4.1 μm (x̅ = 21 × 3.7 μm, n=30), 1–2-seriate, fusiform, hyaline, straight or slightly curved, 1(–3)-septate, mostly 3-septate, constricted at the septa, narrower towards both end cells, smooth-walled, guttules, with an entire mucilaginous sheath. Asexual morph: Undetermined.

Culture characteristics: Ascospores germinating on PDA within 24 h at room temperature. Germ tubes are produced from the apical or the second cell of the ascospore. Colonies on PDA, reaching 25 mm diameter after 2 weeks at 20–25℃, mycelia superficial, circular, flat, fimbriate, entire edge, gray with gray white at the center; reverse, atrovirens, pale yellow at the center.

Material examined: China, Yunnan Province, Baoshan, on dead woody twigs of Dipterocarpus gracilis (Dipterocarpaceae), 12 July 2020, G.C. Ren, BS16 (HKAS 122873), living culture KUMCC 21-0505.

GenBank submissions – ITS: OQ771948, LSU: OQ771954, SSU: OQ771961.

Notes: Phookamsak et al. (2019) introduced Lophiotrema mucilaginosis as a new species collected on dead wood from Yunnan Province, China. Comparatively, the features of our new collections are similar to L. mucilaginosis in having immersed ascomata with ostiolate; carbonaceous ostiole with crest-like opening, filled with hyaline periphysate; cylindrical asci with an ocular chamber; fusiform, hyaline, 1(–3)-septate ascospores with an entire mucilaginous sheath, but our new collections had smaller asci (81 × 7.5 μm vs. 127.5 × 14.5μm) and ascospores (22 × 4 μm vs. 39.1 × 8.6μm) (Phookamsak et al., 2019; Figure 2.64). In our phylogenetic study, the multi-gene phylogenetic analysis based on the combined LSU, LSU, ITS, tef1-α, and rpb2 sequences showed that our new strain clustered with L. hydei and L. mucilaginosis with 89% ML bootstrap support (Figure 2.64). Comparison of LSU and ITS sequence data reveals no significant difference between our new isolates and Lophiotrema mucilaginosis. Therefore, we identify our collection as a new host record of Lophiotrema mucilaginosis on Dipterocarpus gracilis from Yunnan Province, China.

Figure 1. Phylogenetic tree generated from maximum likelihood analysis (RAxML) based on a combined ITS, LSU, SSU, TEF1-α and RPB2 sequence dataset of genera in Lophiotremataceae. Maximum likelihood bootstrap support values greater than 70% and Bayesian posterior probabilities greater than 0.95 BYPP are indicated on the branches. The new isolate is in blue. The type strains are in bold. The tree is rooted with Cryptocoryneum akitaense (KT 3019).