Hermatomyces nabanheensis Tibpromma, Bhat & K.D. Hyde, Fungal Diversity 87: 39 (2017)

Index Fungorum number: IF 552901; MycoBank number: MB 552901; Facesoffungi number: FoF 03135; Fig. 1

Saprobic on dead rachis of Cyathea spinulosa. Sexual morph Undetermined. Asexual morph Hyphomycetes. Colonies on natural substrate dry, blackish brown, superficial, circular or oval, bird nest-like, doughnut-shaped, scattered, blackish brown, glistening, conidia readily liberated when disturbed. Mycelium 1.7–3.3 μm wide, superficial, composed of a network of branched, septate, hyaline to pale brown. Conidiophores are reduced to Conidiogenous cells, micronematous, short, hyaline to pale brown, arising from prostrate hyphae at the centre of circular colony. Conidiogenous cells 4–5.5 (–8.5) × 2.4–3.7, holoblastic, monoblastic, integrated, terminal, cylindrical, hyaline to subhyaline. Conidia dimorphic, lenticular and cylindrical, thick-walled. Lenticular conidia 30–39 × 20–28 μm (x̅=34×23.5 μm, n=20), numerous, thick-walled, central cells dark brown, hyaline to pale brown peripheral cells with septa, forming a distinct ring on the outside. Cylindrical conidia 32–39×19.5–27 μm (x̅=36×24 μm, n=15) μm in broadest part of lower cells, with 2 forked columns of 2–4 cells, cylindrical, swollen, constricted at septa, subhyaline, upper part of terminal cells dark brown, granulate, rough.

Culture characteristics – Conidia germinated on PDA within 15 h at incubator at 25ºC. Germ tubes produced around conidia and were transferred to fresh PDA media. Pure cultures were incubated at 25ºC and reaching 2.2 cm diam. in 10 days, circular, smooth surface, velvety and raised, gray to brown to gray from center to margin from the forward of culture, yellow–brown in the centre while white at the edge from the reverse of culture.

Material examined – CHINA, Guizhou Province, Zunyi, Chishui, Hushi, Chishui Alsophila Natural Reserve (28°29′43″ N 106°0′24″ E), on dead rachis of Cyathea spinulosa, 22 September 2019, J.Y. Zhang, C30 (MFLU 21-0025, new record), living culture, MFLUCC 21-0024.

GenBank numbers – ITS=MZ198895, LSU=MZ198897.

Notes – The phylogenetic analysis based on multigene phylogenetic analysis indicates that our new isolate clustered together with the ex-type strain Hermatomyces nabanheensis (KMUCC 16-0149) with 100% MLBP, 1.00 BYPP support (Fig. 2). A comparison of base pair sequences between H. nabanheensis (KMUCC 16-0149; Hyde et al. 2017) and our isolate (MFLUCC 21-0024) showed that they differ by 3 bases in LSU and 5 bases in ITS. The new isolate is similar to H. nabanheensis (KMUCC 16-0149) in shape of colony, conidiophores, conidiogenous cells and conidia (Hyde et al. 2017). However, the new isolate differs from H. nabanheensis (HKAS96214) in having larger conidia (lenticular conidia 30–39 × 20–28 μm vs. 20.2–25 × 16.6–20.7; cylindrical conidia 30–37×19.5–25 μm vs. 15–26.8×12.1–18.2) (Fig. 1). Based on the evidence of phylogeny and morphological characteristics, we consider the new isolates conspecific to H. nabanheensis and this is the first record of H. nabanheensis from a fern (Cyathea spinulosa).

Figure 1 – Hermatomyces sphaericoides (MFLU 21-0054, new record). a, b Colonies on the natural substrate. c–e Conidiogenous cells. f–i Conidia. j Germinated conidium. k, l Culture on PDA from surface and reverse at 1 month. Scale bars: c–e, j=20 μm, f–i=10 μm

Figure 2 – Phylogram generated from maximum likelihood analysis based on combined ITS, LSU and TEF1-α sequence data of Hermatomyces taxa (Hermatomycetaceae) and closely related families Aquasubmersaceae and Anteagloniaceae .Elsinoecentrolobi CBS 222.50 and E. veneta CBS 150.27 are selected as the outgroup taxa. Bootstrap support values for maximum likelihood (MLBS, left) equal to or greater than 70% is given above or below the nodes. Bayesian posterior probabilities (BYPP, right) equal to or greater than 0.95 are given above the nodes. Ex-type strains are in bold and newly generated sequences are in blue