Nigrograna schinifolium H. M. Hu & Q. R. Li, 2023

Hu, Hongmin, He, Minghui, Wu, Youpeng, Long, Sihan, Zhang, Xu, Liu, Lili, Shen, Xiangchun, Wijayawardene, Nalin N., Meng, Zebin, Long, Qingde, Kang, Jichuan & Li, Qirui, 2023, Taxonomic and phylogenetic characterisations of six species of Pleosporales (in Didymosphaeriaceae, Roussoellaceae and Nigrogranaceae) from China, MycoKeys 100, pp. 123-151 : 123

Nigrograna schinifolium H. M. Hu & Q. R. Li sp. nov.

Fig. 8

Type material.

Holotype. GMB0498.

Etymology.

With reference to the host, Zanthoxylum schinifolium Sieb. & Zucc.

Description.

Saprobic on dead stem of Z. Schinifolium.

Sexual morph:

Ascomata 198-320 μm wide, 105-160 μm high, solitary or aggregated in small groups, black, semi-immersed, appearing as slightly raised regions. Ostioles are black, lined with paraphyses. Peridium 26-39 μm wide, comprising several fused layers of "textura angularis", thin-walled and pale brown at the interior, becoming darker and thicker-walled to the outside. Hamathecium comprising 1-2 μm wide, cylindrical to filiform, septate, branched, pseudoparaphyses, embedded in a gelatinous matrix. Asci 44-59 × 8-10 μm (average = 51.5 × 9.3 μm, n = 25), 8-spored, bitunicate, fissitunicate, cylindrical to broadly filiform, with a short stipe and knob-like base, apically rounded with a minute ocular chamber. Ascospores 10-14 × 2.8-4 μm (average = 11.6 × 3.3 μm, n = 40), broadly fusiform to inequilaterally ellipsoid, with the second cell slightly enlarged, straight or slightly curved, with obtuse to rounded ends, hyaline when immature, becoming brown to dark brown at maturity, 3-euseptate, slightly constricted at the median septum. Asexual morph: undetermined.

Culture characters.

After 4 weeks at 25 °C, colonies on PDA have a diameter of 2-2.5 cm and are circular, slightly raised to umbonate and dull with an entire edge. They appear floccose and smooth and droplets can be observed due to cellular respiration, water formation or antibiotic production. Colonies from the upper region have brown to cream-coloured margins and blackish-brown centres, while their reverse is white to yellowish-brown at the margin and blackish-brown in the centre.

Specimen examined.

China, Guizhou Province, Qiannan Prefecture, Sandu Shui Autonomous County, Yao Man Mountain National Forest Park (25°94′18.76"N, 107°95′70.09"E), 563 m elev., on branches of Zanthoxylum schinifolium , 28 September 2022, Y.P. Wu, 2022YRS36 (GMB0498, holotype, GMBC0498, ex-type; KUN-HKAS 12983, isotype).

Other examined material.

China, Guizhou Province, Huaxi District, Shilihetan Wetland Park (26°23'13.4"N, 106°66'56.4"E), 1501 m elev., on branches of Zanthoxylum schinifolium , 8 October 2022, Y.P Wu and H.M Hu, 2022SLHT44 (GMB0504; GMBC0504, living culture) .

Notes.

Nigrograna schinifolium and N. thymi Mapook et al. form a monophyletic clade with moderate support (MPBP 48%, BYPP 0.83, Fig. 3 ). However, N. schinifolium is distinguished by having 3-septate ascospores ( Hyde et al. 2017). Morphologically, N. schinifolium can be distinguished from other species of Nigrograna by its shorter asci and ascospores ( Hyde et al. 2017; Zhao et al. 2018; Zhang et al. 2020a). Our research confirms N. schinifolium is a new species.

Figures

Figure 3. RAxML phylogram of Nigrogranaceae, based on a combined dataset of ITS and tef 1 DNA sequences. The tree is rooted by Occultibambusa pustula (MFLUCC 11 - 0502) and O. bambusae (MFLUCC 13 - 0855). Bootstrap supports ML (MLB ≥ 75 %) and Bayesian posterior probabilities (BYPP ≥ 0.95) are given as MLB / BYPP above the branches. Sequences from newly-generated isolates are in red, bold letters, while those of ex-type isolates are shown in black, bold letters.

Figure 8. Nigrograna schinifolium (GMB 0498) A specimen B appearance of ascomata on substrate C cross-section of ascomata D longitudinal section of an ascoma E peridium F pseudoparaphyses G - I asci J-L ascospores M, N culture on PDA. Scale bars: 0.5 mm (B-C); 10 μm (D-L).