Phaeoseptoriella poaceicola Y. Gao, H. Gui & K. D. Hyde, 2024

Gao, Ying, Zhong, Tingfang, Eungwanichayapant, Prapassorn Damrongkool, Jayawardena, Ruvishika S., Hyde, Kevin D., Faraj, Turki Kh., Wanasinghe, Dhanushka N. & Gui, Heng, 2024, Two new species of Parastagonospora and a new species of Phaeoseptoriella (Phaeosphaeriaceae, Pleosporales) from grasslands in Yunnan Province, China, MycoKeys 109, pp. 239-263 : 239-263

Phaeoseptoriella poaceicola Y. Gao, H. Gui & K. D. Hyde sp. nov.

Fig. 4

Etymology.

in reference to the holotype occurring on grasses (Poaceae)

Holotype.

HKAS 128741 .

Description.

Saprobic on decaying stem of Dactylis glomerata ( Poaceae ). Sexual morph: Undetermined. Asexual morph: Conidiomata 60–75 μm high × 90–100 μm diam. (x – = 70 × 97 μm, n = 15), flattened, solitary, immersed in the epidermis of the host, globose to subglobose, brown to black spots. Conidiomatal wall 5.5–13 µm wide (x – = 9.5 μm, n = 25), thin wall, 1–4 layered, composed of pale brown cells of textura angularis, with inner layer comprising hyaline cells. Conidiogenous cells (4.1 –) 4–7.7 (– 9.1) × (4 –) 4.3–5.7 (5.5) μm (x – = 5.9 ± 1.82 × 5 ± 0.70 μm, n = 25), hyaline, globose to subglobose, smooth-walled. Conidia (30 –) 33–39 (– 41) × (4.3 –) 5–6 (– 6.7) μm (x – = 36 ± 3.23 × 5.5 ± 0.56 μm, n = 35), phragmosporous, initially hyaline, becoming pale yellowish at maturity, 7 - septate, cylindrical to subcylindrical, straight or slightly curved, smooth-walled, rounded at apex, slightly truncate at base, guttulate.

Culture characteristics.

Colonies on PDA, reaching 10–20 mm diam., after three weeks at 25–27 ° C, with irregular, floccose, raised, white from the above and in reverse yellow.

Material examined.

China • Yunnan Province, Zhaotong City (27 ° 38 ' 37 " N, 103 ° 37 ' 5 " E), on decaying stem of Dactylis glomerata ( Poaceae ), 25 September 2022, Ying Gao, LG 7 A ( HKAS 128741 , holotype), ex-type ( CGMCC 3.24561 ) • ibid. LG 7 B ( HKAS 128742 , paratype), ex-paratype ( CGMCC 3.24562 ) . ibid. • China, Yunnan Province, Zhaotong City , (27 ° 26 ' 34 " N, 103 ° 19 ' 16 " E), on decaying stems of Anaphalis tenuisissima , 20 August 2021, Ying Gao, living cultures: ZY 356 B ( CGMCC 3.25058 ), ZY 359 A ( CGMCC 3.25059 ), ZY 359 B ( CGMCC 3.25060 ) .

Note.

Phaeoseptoriella poaceicola is introduced as a new species based on morphology and phylogenetic analysis of combined SSU, LSU, ITS, tef 1 - α, and rpb 2 datasets. Our strains of Phaeoseptoriella poaceicola ( CGMCC 3.24561 , CGMCC 3.24561 , CGMCC 3.25058 , CGMCC 3.25059 , and CGMCC 3.25060 ) distinct clade (100 % ML, 1.00 PP, Clade C, Fig. 1 ). The ITS pairwise nucleotide comparison of our isolate Phaeoseptoriella poaceicola ( CGMCC 3.24561 ) with Phaeoseptoriella edithcowaniae (PP 707905), Ph. emmelinepankhurstiae (OR 673891), Ph. vidagoldsteiniae (OR 673892), Ph. zeae (NR _ 163371) showed 123 / 601 bp, 83 / 537 bp, 81 / 537 bp, 88 / 534 bp, differences (20.47 %, with 37 gaps; 15.46 %, with 27 gaps; 15.08 %, with 25 gaps; 16.48 %, with 28 gaps), respectively. Our isolate differs from Ph. edithcowaniae (PP 708933) and Ph. zeae (NG _ 067869) in 13 / 836 bp and 4 / 836 (1.56 % and 0.48 % without gaps) in the LSU regions, respectively. It differs from Ph. zeae ( MK 442674 ) in 130 / 878 bp (14.81 %, without gaps) in the rpb 2 regions, SSU and tef 1 - α of other Parastagonospora species were not provided. Phaeoseptoriella only included four species, however, Ph. emmelinepankhurstiae , Ph. edithcowaniae , and Ph. eidagoldsteiniae have not provided with morphological analyses ( Tan and Shivas 2023, 2024). Phaeoseptoriella poaceicola differs from Ph. zeae in comparatively smaller conidiomata (90–100 μm diam. vs. 200–250 μm diam.), conidiogenous cells (hyaline, globose to subglobose vs. pale brown, ampulliform to doliiform), bigger conidia (30–41 μm long, 4–7 μm wide, cylindrical to subcylindrical, 7 - septate, vs. 14–23 μm long, 3–4 μm wide, fusoid-ellipsoid, 3 - septate) ( Crous et al. 2019). Based on the guidelines for a polyphasic approach recommended for species boundary delimitation ( Chethana et al. 2021; Maharachchikumbura et al. 2021), we introduce Phaeoseptoriella poaceicola as a novel taxon.

Figures

Figure 1. Phylogenetic tree obtained from combined SSU, LSU, ITS, tef 1 - α, and rpb 2 sequence data. The tree is rooted with Quixadomyces hongheensis (HKAS 112346 and KUMCC 20-0215). Bootstrap support values for ML equal to or greater than 60 % and the Bayesian posterior probabilities equal to or higher than 0.95 PP are indicated above the nodes as ML / PP. Ex-type strains are indicated in bold, and the new isolates are highlighted in blue.

Figure 4. Asexual morph of Phaeoseptoriella poaceicola (HKAS 128741, holotype) on a dead stalk of Dactylis glomerata a, b conidiomata on the host c, d vertical section of conidiomata e conidioma wall i conidiogenous cell arise from the wall and develop conidium f – h, j conidia k germinating conidium l cultures on PDA from above m cultures on PDA from the reverse. Scale bars: 30 μm (c); 20 μm (d, e, k); 10 μm (f – h, j); 5 μm (i).