Byssosphaeria poaceicola Tennakoon & D. M. Hu, 2024

Tennakoon, Danushka S., Thambugala, Kasun M., de Silva, Nimali I., Song, Hai-Yan, Suwannarach, Nakarin, Chen, Fu-Sheng & Hu, Dian-Ming, 2024, An overview of Melanommataceae (Pleosporales, Dothideomycetes): Current insight into the host associations and geographical distribution with some interesting novel additions from plant litter, MycoKeys 106, pp. 43-96 : 43-96

Byssosphaeria poaceicola Tennakoon & D. M. Hu sp. nov.

Fig. 5

Etymology.

Named after the host family ( Poaceae ) where this fungus was collected.

Holotype.

HFJAU 10338 .

Description.

Saprobic on dead stem of Arundo pliniana Turra ( Poaceae ). Sexual morph: Ascomata 550–650 × 600–800 µm (x ̄ = 610 × 715 μm, n = 10), solitary to gregarious, superficial, dark brown to black, setose, coriaceous, unilocular, globose to subglobose, non-papillate, apex rounded with an orange to yellow ostiole, ostiole central, with pore-like opening, periphysate. Peridium 30–45 μm wide, thick-walled, composed of 6–7 layers of dark brown cells, orange to yellow near ostiole, arranged in textura angularis. Hamathecium 1–2.5 μm wide, comprising dense, filiform, anastomosing, septate, trabeculate pseudoparaphyses, embedded in a gelatinous matrix. Asci 165–180 × 12–15 μm (x ̄ = 171 × 13 μm, n = 20), 8 - spored, bitunicate, fissitunicate, cylindrical clavate, apically rounded, long pedicellate (30–40 μm), with an indistinct ocular chamber. Ascospores 32–40 × 7–8 μm (x ̄ = 36 × 7.5 μm, n = 30), overlapping, 1–2 - seriate, ellipsoid to fusiform, initially hyaline, pale brown when mature, 1 - septate, constricted at the septum, slightly curved, guttulate, smooth-walled. A sexual morph: Undetermined.

Material examined.

China, Yunnan Province, Kunming , on a dead stem of Arundo pliniana ( Poaceae ), 22 July 2016, D. S. Tennakoon, KDS 30 ( HFJAU 10338 , holotype) ; ibid. 28 August 2016, KDS 29 ( HFJAU 10337 , paratype).

Notes.

In the combined LSU, SSU, ITS and tef 1 - α phylogenetic analysis, two strains of Byssosphaeria poaceicola ( HFJAU 10337 and HFJAU 10338 ) formed a monophyletic clade sister to By. phoenicis strains ( ZHKUCC 21-0122 and ZHKUCC 21-012 ) with 83 % ML and 0.99 BYPP statistical support. Morphologically, they share similarities in having superficial, dark brown to black, coriaceous, non-papillate ascomata, cylindrical clavate asci and ellipsoid to fusiform, 1 - septate, pale brown ascospores ( Kularathnage et al. 2022). Although Byssosphaeria poaceicola can be distinguished from By. phoenicis in their size differences of asci (165–180 × 12–15 μm vs. 100–160 × 10–15 μm) and ascospores (32–40 × 7–8 μm vs. 25–30 × 5–7 μm) ( Kularathnage et al. 2022). In addition, a comparison of the 497 nucleotides across the ITS (+ 5.8 S) gene region of By. poaceicola and By. phoenicis shows 16 base pair differences (3.21 %). It is interesting to notice that the Byssosphaeria species have not been collected much from Poaceae hosts, except for bamboo species ( Jiang et al. 2022). Based on this finding, it appears that Byssosphaeria species can adapt to a variety of habitats, although there are limited studies to investigate their diversity on various hosts and regions.

Figures

Figure 5. Byssosphaeria poaceicola (HFJAU 10338, holotype) a, b appearance of ascomata on the host c vertical section of an ascoma d ostiole e peridium f pseudoparaphyses g – i asci j – o ascospores. Scale bars: 200 µm (c); 20 µm (d, e); 50 µm (f – i); 10 µm (j – o).