Cladophialophora aquatica M.S. Calabon, Boonmee, E.B.G. Jones & K.D. Hyde, sp. nov.

Index Fungorum number: IF 558644;  MycoBank number: MB 558644; Facesoffungi number: FoF 09153; Fig. 1

Etymology – Name reflects the aquatic habitat from where this species was collected.

Holotype – MFLU 21-0119

Saprobic on submerged decaying wood in a freshwater. Sexual morph Undetermined. Asexual morph Hyphomycetous. Hyphae 1.2–4 μm wide, septate, hyaline to lightly pigmented. Chlamydospores 8–13.5×3.5–9 μm (x̅=10.5–6 μm, n=30), numerous, mostly in chains, intercalary or solitary, globose to subglobose, smooth, olivaceous brown to dark brown.

Culture characteristics – Colonies growing on MEA, reaching 20–30 mm in 2 weeks at 25 °C. Mycelia superficial, circular, with entire margin, flat, smooth, from above gray, from below dark brown. Chlamydospores produced in culture and induced with plant tissues within 30 days.

Material examined – THAILAND, Chiang Mai Province, Mushroom Research Center, on submerged decaying wood in a freshwater habitat, 11 February 2019, M.S. Calabon, MC03 (MFLU 21-0119, holotype), ex-type living culture, MFLUCC 21-0108.

GenBank numbers – ITS=MT864355, LSU=MT860433.

Notes – Unlike other species of Cladophialophora, C. aquatica did not produce conidial chains in culture but chlamydospores were prominent and numerous (Fig. 1). One strain of Cladophialophora immunda CBS 109797 and C. tortuosa produced chlamydospores in culture infrequently (Badali et al. 2008; Obase et al. 2016). In the phylogenetic analysis of LSU and ITS sequence data, Cladophialophora aquatica clustered with C. exuberans, C. matsushimae and C. mycetomatis with only 1.00 BYPP support (Fig. 2). Cladophialphora matsushimae differs in having conidial chains that resembles septate vegetative hyphae and subcylindrical conidia, ramoconidia, and microconidia (Koukol 2010). Cladophialphora exuberans and C. mycetomatis differ from C. aquatica in having conidiogenous cells that sympodially proliferate with a few conidiogenous loci, and the presence of ramoconidia and conidia (Badali et al. 2008; Nascimento et al. 2017).

Figure 1 – Cladophialophora aquatica (MFLUCC 21-0108, ex-type). a Culture on MEA from surface and reverse. b–m Chlamydospores. Scale bars: b=300 μm, c, d=50 μm, e–m=20 μm

Figure 2 – Phylogram generated from maximum likelihood analysis based on combined LSU and ITS sequence data representing the species of Cladophialophora. Related sequences are taken from Kiyuna et al. (2018). Rhopalophora clavispora (CBS 637.73) and Fusichalara minuta (CBS 709.88) were used as the outgroup taxa. Fifty-three taxa are included in the combined analyses which comprised 1041 characters (502 characters for LSU, 539 characters for ITS) after alignment. The best scoring RAxML tree with a final likelihood value of − 9519.130038 is presented. The matrix had 524 distinct alignment patterns, with 16.53% of undetermined characters or gaps. Estimated base frequencies were as follows: A=0.236745, C=0.249453, G=0.269107, T=0.244695; substitution rates: AC=1.891141, AG=3.179450, AT=1.427526, CG=0.913317, CT=6.628918, GT=1.000000; gamma distribution shape parameter α=0.260996. The MP analysis resulted a single most parsimonious tree (TL=1789, CI=0.455, RI=0.710, RC=0.323, HI=0.545). Bootstrap support values for MLBS and MPBS equal to or greater than 75% and BYPP 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