Nigrospora yunnanensis M. T. Zou & Yong Wang bis

Zou, Mengting, Al-Otibi, Fatimah, Hyde, Kevin David, Wang, Yong & Pan, Xue-Jun, 2024, New Helminthosporium (Massarinaceae, Dothideomycetes) and Nigrospora (Incertae sedis, Sordariomycetes) species associated with walnut (Juglans regia L.) in China, MycoKeys 109, pp. 265-284 : 265-284

Nigrospora yunnanensis M. T. Zou & Yong Wang bis sp. nov.

Fig. 4 a – k

Etymology.

The name refers to Yunnan, the province where the fungus was collected.

Diagnosis.

Nigrospora yunnanensis is characterized by black, globose conidia (16.2 × 14.4 µm).

Type.

China • Yunnan Province: Lincang City ; 23 ° 40 ' 26.08 " N, 99 ° 56 ' 47.70 ″ E; 1900 m; 22 Dec 2023; on Juglans regia , coll. M. T. Zou; HGUP 24-0007 (holotype); ex-type culture GUCC 24-0008 ( ITS: PP 915796 , tef 1 - α: PP 947933, tub 2: PP 947937) .

Culture characteristics.

Colonies on PDA reaching 90 mm diam after ten days at 25 ° C. The anterior surface and posterior surface are white, while the mycelium is thick and fluffy. Colonies on OA reach 90 mm diam. after ten days at 25 ° C. The mycelium is circular, filiform, fluffy, while the surface and reverse are initially white, becoming gray to black, or black and producing a few black areas with age. Colonies on MEA reaching a diameter of 90 mm after ten days at 25 ° C. The mycelium circular, filiform, thick, and fluffy. The surface and reverse are initially white, but they become gray to dark black with abundant black areas spreading from the periphery to the center as they age. Sexual morph undetermined. Asexual morph on OA: Hyphae 2.5–8 µm diam, smooth, hyaline to pale brown, branched, septate. Conidiophores smooth, hyaline to brown, branched, septate, sometimes reduced to conidiogenous cells. Conidiogenous cells (n = 30) 8–14 × 6–10 µm (av. = 10.4 × 8.2 µm), aggregated in clusters on hyphae, pale brown, subglobose to ampulliform. Conidia (n = 40) 14.5–18.5 × 11–17.5 µm (av. = 16.2 × 14.4 µm) solitary, globose to subglobose, black, shiny, smooth, aseptate.

Habitat.

On Juglans regia .

Known distribution.

China, Yunnan Province, Lincang city.

Additional material examined.

China • Yunnan Province: Lincang city; 23 ° 67 ' N, 99 ° 94 ' E; 1900 m; 22 Dec 2023; on Juglans regia ; coll. M. T. Zou; HGUP 24-0007 ; living culture GUCC 24-0008, GUCC 24-0009, and GUCC 24-0010 .

Notes.

Three isolates from walnut leaves were obtained in this study and clustered in a well-supported clade distinguished from other known species (Fig. 4 ). Nigrospora yunnanensis formed an independent branch. Morphological differences (Table 2 ) support that they belong to different taxa.

Figures

Figure 4. Nigrospora yunnanensis (GUCC 23-0008) a – c culture characteristics on media after ten days (a on PDA b on CMA c on OA) d – j conidia attached to conidiogenous cells k coiled hyphae. Scale bars: 10 µm (d – k).