Pleosporales » Didymosphaeriaceae » Dictyoarthrinium

Dictyoarthrinium thailandicum

Dictyoarthrinium thailandicum G.C. Ren and K.D. Hyde, Biology 11(no. 1660): 15 (2022)

Index Fungorum number: IF 559807. FacesofFungi number: FoF 10705.

Saprobic on dead woody twigs of Castanopsis sp. Sexual morph: undetermined. Asexual morph: Colonies solitary, irregular, black. Mycelium superficial, septate, branched, anastomosing hyphae. Conidiophores 130–220 × 4–5 µm ( = 180 × 4.5 µm, n = 25), erect, macronematous, basauxic, cylindrical, straight or flexuous, sub-hyaline-to-pale-brown, the transverse septa partly brown with distances of 3–7 µm, rough-walled. Conidiophore mother cells 4–4.5 × 3.8–4.1 µm ( = 4.5 × 4 µm, n = 10), cup-shaped, pale brown. Conidiogenous cells 3–7 × 3–5 µm ( = 5 × 4 µm, n = 20), blastic, integrated, terminal and intercalary, cylindrical, sub-hyaline. Conidia 9–11 × 8.5–10.5 µm ( = 10 × 9.7 µm, n = 30), solitary, holoblastic, spherical, 1-celled and sub-hyaline-to-pale-brown when young, cruciate-septate with four cells, constricted at the septa, rounded at the ends, spherical or subspherical, brown-todark- brown at maturity, verrucose, mature conidia split along one line of the septa, arising from the lateral or apical part of conidiophores.

Culture characteristics: The colonies on PDA reached 15–20 mm diam. After 14 days at room temperature (25–30 ºC), superficial, circular, umbonate at the center, rough surface, with dense mycelia, velvety, flat, and white.

Material examined: Thailand, Chiang Mai Province, Yang Piang Omkoi, on dead woody twigs of Castanopsis sp., 25 August 2019, G.C. Ren, YP01 (MFLU 22-0040, holotype), ex-type culture KUMCC 21-0664; ibid, Tak Province, Moe Wa Luang Tha Song Yang, on dead woody twigs of Castanopsis sp., 17 October 2019, G.C. Ren, TSY02 (MFLU 22-0041, paratype), ex-paratype culture KUMCC 21-0665.

Notes: Dictyoarthrinium thailandicum is introduced as a new species based on its distinct morphology and the phylogeny of the combined SSU, LSU, ITS, tef 1- dataset. This species is phylogenetically distinct from other Dictyoarthrinium species and formed a clade sister to D. musae with 76% ML bootstrap and 1.00 BYPP support. This species is similar to D. musae in having black colonies, cup-shaped conidiophore mother cells, and cylindrical conidiogenous cells. However, the size of the conidiophores and conidia of D. thailandicum (180 × 4.5 µm, 10 × 9.7 µm) is comparatively larger than those of D. musae (81.5 × 1.6 µm, 8.7 × 7.9 µm)

 

Figure 1. Phylogram generated from ML analysis based on the combined SSU, LSU, ITS, and tef 1- dataset. Bootstrap support values for ML equal to or higher than 75%, and BYPP equal to or greater than 0.90 are shown above the nodes.

 

Figure 2.  Dictyoarthrinium thailandicum (MFLU 22-0040, holotype). (a,b) Conidia on the host; (c–e) conidia with conidiophores on stalk; (f,g) developmental stage of an immature lateral conidium; (h) four-celled terminal conidium; (i–l) warted four-celled mature conidia; (m) germinated conidia; (n,o) culture characters on PDA. Scale bars, (c,e) 100 μm; (d) 50 μm; (f–h) 15 μm; (i–m) 10 μm; (n,o) 30 mm.

 

References

1. Ren GC, Wanasinghe DN, de Farias ARG, Hyde KD et al. (2022) Taxonomic Novelties of Woody Litter Fungi (Didymosphaeriaceae, Pleosporales) from the Greater Mekong Subregion. Biology, 11, 1660, Doi /10.3390/biology11111660.

 

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