Tetraploa nagasakiensis (Kaz. Tanaka & K. Hiray.) Kaz. Tanaka & K. Hiray., Fungal Divers 63: 253 (2013)

Basionym: Tetraplosphaeria nagasakiensis Kaz. Tanaka & K. Hiray., in Tanaka et al., Stud Mycol 64: 180 (2009)

Index Fungorum number: IF 801978;  MycoBank number: MB 801978; Facesoffungi number: FoF 05080; Fig. 1

Saprobic on dead stem of Hedychium coronarium J. Koenig. Sexual morph: Ascomata 150–210 μm high×140–250 μm diam. (x=180×205 µm, n=10), solitary or scattered, coriaceous, immersed to erumpent, visible as black dots on the host surface, unilocular, globose to subglobose, brown to dark brown, ostiolate, with minute papilla, filled with short, hyaline periphyses. Peridium 16–25 μm wide, comprising light brown cells of textura angularis, fusing at the outside indistinguishable from the host tissues. Hamathecium comprising 1.2–1.8 μm wide, cylindrical to filiform, septate, branched, pseudoparaphyses. Asci 100–115 × 14–17 μm (x=108 × 15 μm, n=20), 8-spored, bitunicate, clavate to cylindrical, short pedicellate, with ocular chamber. Ascospores 28–34 × 4–5 μm (x=30×4.2 μm, n=30), overlapping 1–2-seriate, hyaline, narrowly fusiform with acute ends, slightly curved, 1-septate, constricted at the septum, smooth-walled. Asexual morph: Undetermined.

Culture characteristics – Colonies on PDA, 16–20 mm diam. after three weeks, colonies from above: medium dense, circular, flat, slightly raised, surface smooth with crenate edge, with smooth aspects, grey to dark brown at the margin, light brown in the center; reverse: dark brown to black at the margin, brown to grey in the center.

Material examined – China, Yunnan Province, Baoshan, dead stem of Hedychium coronarium (Zingiberaceae), 22 August 2017, D.S. Tennakoon, DS009 (MFLU 18-0089); living culture, MFLUCC 17-2647.

Hosts and distribution – Bamboo (Poaceae) in China, Japan; Hedychium coronarium (Zingiberaceae) in China (Tanaka et al. 2009; Hyde et al. 2019a).

GenBank numbers – ITS: OQ970538, LSU: OQ970466; SSU: OQ970468

Notes – Tetraplosphaeria nagasakiensis was introduced by Tanaka et al. (2009) from culms of bamboo in Japan. Subsequently, this species was synonymized by Hyde et al. (2013) as Tetraploa nagasakiensis. This has been recorded from dead bamboo branches in China as well (Hyde et al. 2019a). The morphological characteristics of our collection (MFLU 18-0089) fit well with the Tetraploa nagasakiensis in having immersed to erumpent, unilocular, globose to subglobose, coriaceous ascomata, clavate to cylindrical, short pedicellate asci and hyaline, narrowly fusiform, 1-septate ascospores (Tanaka et al. 2009; Hyde et al. 2019a). Multigene phylogeny (Fig. 2) also indicate that our collection (MFLU 18-0089) clusters with Tetraploa nagasakiensis in 93% ML, 91% MP, 0.99 BI support. Therefore, based on both morphology and phylogeny evidence, we introduce our collection as a new host record of Tetraploa nagasakiensis from Hedychium coronarium (Zingiberaceae).

Figure 1 – Tetraploa nagasakiensis (MFLU 18-0089). a, b Appearance of ascomata on substrate. c, d Vertical cross-sections through ascomata. e Vertical cross-sections through neck region. f Peridium. g Pseudoparaphyses. h, i Asci. j–n Ascospores. o A germinating ascospore. p Colony on PDA from above. q Colony on PDA from below. Scale bars: c, d=80 μm, e=20 μm, f, j–o=10 μm, g–i=50 µm

Figure 2 – Phylogram generated from maximum likelihood analyses based on combined LSU, ITS, SSU, β tubulin and tef1-α sequence data which comprised 3716 characters (LSU=852, ITS=571, SSU=1,336, β tubulin=639, tef1-α=318). The best scoring RAxML tree with a final likelihood value of f − 20,590.306011 is presented. The matrix had 1192 distinct alignment patterns, with 32.10% of undetermined characters or gaps. Estimated base frequencies were as follows: A=0.239693, C=0.252943, G=0.275644, T=0.231720; substitution rates AC=2.413323, AG=3.943519, AT=1.709808, CG=1.421703, CT=8.021695, GT=1.0; gamma distribution shape parameter α=0.164747. Bootstrap support for ML and MP equal to or greater than 75% and Bayesian posterior probabilities equal to or greater than 0.95 (the rounding of values to 2 decimal proportions) are labelled at each node. Ex-type strains are in bold, while the new isolates are indicated in blue bold. The tree is rooted to Muritestudina chiangraiensis (MFLUCC 17-2551)