Minimelanolocus submersus Z.L. Luo, H.Y. Su & K.D. Hyde

Wan, Yi-Le, Bao, Dan-Feng, Luo, Zong-Long, Bhat, Darbhe-Jayarama, Xu, Yue-Xin, Su, Hong-Yan & Hao, Yu-E, 2021, Two new species of Minimelanolocus (Herpotrichiellaceae, Chaetothyriales) from submerged wood in Yunnan, China, Phytotaxa 480 (1), pp. 45-56 : 53

Minimelanolocus submersus Z.L. Luo, H.Y. Su & K.D. Hyde , Fungal Diversity 80: 143 (2016). ( Fig. 4 )

Index Fungorum number: IF552154, Facesoffungi number: FoF02219

Saprobic on submerged wood in aquatic habitats. Asexual morph: hyphomycetous on woody substrate, superficial, effuse, hairy, scattered, dark brown or black. Mycelium mostly immersed, consisting of septate, dark brown to black, smooth hyphae. Conidiophores 165–405 × 7–9 μm (x = 286 × 8 μm, n = 8), mononematous, macronematous, erect, smooth-walled, straight or slightly flexuous, unbranched, cylindrical, dark brown, gradually becoming subhyaline to pale brown towards apex, smooth, septate. Conidiogenous cells denticulate, terminal, becoming intercalary, holoblastic, thin-walled, integrated, indeterminate, subhyaline to pale brown, sympodially extending. Conidia 37–49 × 6–8 μm (x = 43 × 7 μm, n = 20), acropleurogenous, solitary, clavate to fusiform, erect or slightly curved, subhyaline or pale brown, 1-septate when young, 5–7-septate at maturity, not constricted at septa, conidial secession schizolytic. Sexual morph: Undetermined.

Material examined:— CHINA, Yunnan Province, Nujiang River , 1219m, 27.02105°E, 98.52060°N, on submerged decaying wood, 4 May 2015, Q. Dai, S-352, ( DLU 325 ), living culture, DLUCC 325 .

Notes: —Phylogenetic analysis showed that our new collection (DLUCC 325) clustered with M. submersus (KUMCC 15–0206) with low bootstrap support ( Fig. 1 ). The comparison of the base pairs of the ITS and LSU gene regions for both strains revealed, 5 and 1 base pair differences, respectively.Although our collection (DLUCC 325) has similar morphology with the holotype of M. submersus ( Hyde et al. 2016b) , there are some morphological differences between them. Our collection has longer and wider conidiophores (165–405 × 7–9 μm vs. 110–180 × 5–6 μm) and larger conidia (37–49 × 6–8 μm vs. 19–33 × 3.5–4.5 μm). Our isolate has more septa (1–7-septate) than the holotype (1–5-septate). There are no other significant morphological differences to distinguish these strains, therefore, we identified the new isolate as M. submersus based on multi-loci phylogeny and morphological characters. Both M. submersus strains, KUMCC 15–0206 and DLUCC 325, were collected from submerged wood in Dali, Yunnan and their morphological differences probably reveal that different growing environments cause subtle differences. Our specimen was collected from Nujiang River (lotic habitat) while the holotype was obtained from Erhai Lake (lentic habitat) and this may affect morphological characters. The heterogeneities and variations may provide freshwater ascomycetes an adaption to aquatic life ( Raja et al. 2018).

Figures

FIGURE 1. Phylogenetic tree based on RAxML analyses of a combined ITS, LSU and SSU dataset. Bootstrap support values for maximum likelihood (MLBS) higher than 75% and Bayesian posterior probabilities (PP) greater than 0.95 are indicated above the nodes as MLBS/PP. The tree is rooted to Cyphellophora sessilis (CBS 243.85) and C. oxyspora (CBS 698.73). Ex-type strains are in bold and newly generated sequences are in red.

FIGURE 4. Minimelanolocus submersus (DLU 325). a.Appearance of the colony on wood. b–c. Conidiophores and developing conidia. d–g. Conidiogenous cells. h–q. Conidia. r. Germinated conidium. s, t. Colonies on PDA (s. above view, t. reverse). Scale bars: b–d = 50 μm, e–r = 20 μm.