Dendryphion hydei J.F. Li, Phookamsak & Jeewon, PLoS ONE 15(2): e0228067 (2020)

Index Fungorum number: IF 556746; MycoBank number: MB 556746; Facesoffungi number: FoF 04574; Fig. 1

Saprobic on submerged wood in a freshwater habitat. Sexual morph Undetermined. Asexual morph Colonies on the substrate superficial, effuse, hairy, brown to dark brown. Mycelium partly immersed to superficial on the substrate, branched, septate, pale brown to brown hyphae. Conidiophores 338–428×10–16 μm (x̅=383×13 μm, n=15) (10–16 μm wide at the base, 5–7 μm wide at the apex branch) macronematous, mononematous, septate, straight or flexuous, cylindrical, thick-walled, simple branch on the top primary branches, pale brown to brown, unbranched part dark brown. Conidiogenous cells 5–9 ×4–5 μm (x̅=7 × 4 μm, n=25) polytretic, terminal, integrated, pale brown. Conidia 33–56 (–108)×6–8 μm (x̅=44×7 μm, n=30) single, dry, drum to globose, pale brown to brown, slightly paler at the end cells, bead-like chains, 4–13(–21)-septate, constricted at the septa, middle cells wider than the top and bottom. Conidial secession schizolytic.

Culture characteristics – Conidia germinated on the PDA within 24 h, and germ tube produced from both ends. Colonies grow on the PDA, and after 2 weeks of incubation at room temperature, the diameter reaches about 4 cm. Hyphae are initially white to light grey, and then gradually become grey to dark grey, with convex middle, flocculent, grey to dark grey, smooth edges, white, and flocculent, forming a white ring about one centimeter. Reverse light yellow–brown, uniform color, smooth.

Material examined – CHINA, Yunnan Province, Puer City, (100°37′59″ E 22°36′36″ N, 919 msl), on submerged wood, 30 April 2018, H.W. Shen, Q.S. Zhou and Z.L. Luo, S-2049 (HKAS 112706, new record), living culture, DLUCC 2049.

GenBank numbers – ITS = MW723060, LSU = MW879527, SSU = MW774583, RPB2=MW729781, TEF1-α: MW729786.

Notes – Dendryphion hydei was found on a branch litter of Bidens pilosa Linn. in Chiang Mai Province, Thailand (Li et al. 2020a). Phylogenetically, our isolate clustered with the ex-type strain of Dendryphion hydei (HKAS 97479) with low statistical support (Fig. 2). Our new isolate (Fig. 1) has some differences in size from the type species; it has longer conidiophores (338–428×10–16 μm vs. 260–380×7–14 μm) and conidia (33–56 (–108)×6–8 μm vs. (17–)20–30(–35) μm long×4–7 μm), and has more septa (4–13 vs. 2–4). Based on morphological data and phylogenetic analysis, we report D. hydei as the first record in a freshwater habitat.

Figure 1 – Dendryphion hydei (HKAS 112706, new record). a Colonies on submerged wood. b–d Conidiophores with conidiogenous cells. e, f Conidiogenous cells with conidia. g–l Conidia. m, n Culture on PDA (surface and reverse). Scale bars: a=200 μm, b, c=50 μm, d–f, h–l=10 μm, g=20 μm

Figure 2 – Phylogram generated from maximum likelihood analysis based on combined LSU, SSU, TEF1-α, RPB2 and ITS sequence dataset representing genera of Torulaceae and other related families in Pleosporales. The updated sequence dataset was derived from Hyde et al. (2020b) and Li et al. (2020a). Forty-seven strains are included in the combined analyses which comprise a total of 4193 characters. Paeadictyoarthrinium diffractun MFLUCC 13-0466 and P. hydei MFLUCC 17-2512 are selected as the outgroup taxa. The best RAxML tree with a final likelihood value of − 20632.568415 is presented. RAxML analysis yielded 1256 distinct alignment patterns and 34.11% of undetermined characters or gaps. Estimated base frequencies were as follows: A=0.246275, C=0.259573, G=0.270969, T=0.223183, with substitution rates AC=1.544243, AG=3.270041, AT=1.437706, CG=0.944551, CT=7.854806, GT=1.000000; gamma distribution shape parameter alpha=0.178530. Bootstrap support values for maximum likelihood (MLBS, left) equal to or greater than 70% is given above 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