Versicolorisporium triseptatum Sat. Hatak., Kaz. Tanaka & Y. Harada, in Sat. Hatak., et al. Mycoscience 49(3):211 (2008).

Index Fungorum number: IF 510910;  MycoBank number: MB 510910; Facesoffungi number: FoF 11622; Fig. 1

Saprobic on decaying culms of bamboo. Sexual morph: Undetermined. Asexual morph: Conidiomata 150–210 × 240–260 μm ( x = 173 × 251 μm, n = 10), pycnidial, subepidermal, solitary or gregarious, black, coriaceous, slightly papillate, ostiolate. Periphyses short, hyaline. Conidiomatal wall 19–43 μm ( x = 28.4 μm, n = 10) wide, comprise of brown, cells of textura angularis. Conidiophores reduce to conidiogenous cells. Conidiogenous cells formed from the inner layer of the conidiomatal wall, ampulliform to cylindrical, holoblastic, bearing a single terminal conidium. Conidia 22–35 × 13–18 μm (x=27.7 × 15.2 μm, n=22), obovoid, rounded at the apex, truncate at the base, 3–4-septate, with a submedian primary septum, smooth; apical cell 3.5–6.5 μm (x=4.4 μm, n=20) long, pale brown; second cell from the apex 12–15 μm (x=13.2 μm, n=20) long, dark brown; third cell 4.5–7.6 μm (x = 5.3 μm, n = 20), long, pale brown; basal cell 2.8–4.6 μm (x = 3.70 μm, n=20) long, hyaline.

Culture characteristics – Colonies on PDA at 25 °C in the dark reached 40 mm in diam. after 3 weeks, circular, flat, entire, filamentous, cottony, surface view grey green; reverse dark olive green.

Material examined – China, Sichuan Province, Qionglai City, Nanmuxi (N 30° 19′ 15, E 103° 7′ 39), on decaying culms of Bambusa sp. (Poaceae), 24 August 2021, Y. Chen, NMX1222 (HUEST 21.0016), living culture UESTCC 21.0016.

Hosts and distribution – On decaying culms of Pleioblastus chino (Franch. & Sav.) Makino and Sasamorpha borealis (Hackel.)Nakai. (Poaceae) in Japan (Hatakeyama et al. 2008),on decaying culms of bamboo in Sichuan, China.

GenBank numbers – ITS: OL741378, LSU: OL741318, SSU: OL741381 

Notes – Versicolorisporium triseptatum is characterized by versicolored conidia formed from holoblastic conidiogenous cells (Hatakeyama et al. 2008). Our collection (HUEST 21.0016) is similar to the holotype of V. triseptatum (JCM 14775= HHUF 28815). The multilocus phylogeny shows that our isolate clustered with the ex-type strain of V. triseptatum with MP/BI=100%/1.00 bootstrap support. Therefore, we identified our isolate (HUEST 21.0016) as V. triseptatum, and this is the first report of V. triseptatum in China (Fig. 2).

Figure 1 – Versicolorisporium triseptatum (HUEST 21.0016). a, b Appearance of conidiomata on decaying culms of bamboo. c Horizontal section through conidioma. d Vertical section through conidioma. e Condia attached to conidiogenous cells. f Germinated conidium. g Surface view of culture. h Reverse view of culture. i–n Conidia. Scale bars: c, d=100 µm, f=20 µm, e, i–j=10 µm

Figure 2 – The best scoring RAxML tree based on a combined dataset of ITS, LSU, SSU, rpb2, and tef1-α sequence data. The topology and clade stability of the combined gene analyses was compared to the single gene analyses and no significant differences. The tree is rooted with Ohleria modesta (CBS 141480). The matrix had 1160 distinct alignment patterns with 22.68% undetermined characters and gaps. Estimated base frequencies were as follows; A=0.248, C=0.265, G=0.258, T=0.229; substitution rates AC=1.811179, AG=4.286074, AT=1.611330, CG=1.379457, CT=8.862589, GT=1.0; gamma distribution shape parameter α=0.148827 and final likelihood value of − 16,694. Ex-type strains are in bold and newly generated sequences are in blue bold. Bootstrap support for ML≥75% and BI≥0.95 are given at the nodes