Botryosphaeriales » Botryosphaeriaceae » Dothiorella

Dothiorella rosacearum

Dothiorella rosacearum N. Wu, A.J. Dissanayake & Jian K. Liu, sp. nov.

Index Fungorum number: IF900579; Facesoffungi number: FoF14259.

Etymology: Referring to the host family Rosaceae on which the type specimen was collected.

Holotype: MFLU 23-0014.

Saprobic on dead twigs of Amygdalus sp. (Rosaceae). Sexual morph: Not observed. Asexual morph: Conidiomata 153–234 × 222–336 μm (x̅ = 187 × 270 μm, n = 20), immersed, scattered, dark brown to black, globose or subglobose, solitary, initially intraepidermal, visible as black dots on the host when mature, thick-walled, glabrous. Ostiole 30–32 μm diam., single, straight, sometimes bent, centrally located. Peridium up to 31–45 μm wide, comprising host and fungal tissues, dark brown to black, 5–10 cell layers of textura angularis, becoming thin-walled and hyaline towards the inner region. Paraphyses absent. Conidiophores are reduced to conidiogenous cells. Conidiogenous cells 4–9 × 3–5 μm (x̅ = 7 × 4 μm, n = 20), hyaline, aseptate, contents granular, cylindrical to ellipsoidal, smooth-walled, unbranched or occasionally branched, with swollen bases. Conidia 17–21 × 7–10 μm (x̅ = 18 × 8 μm, n = 50), hyaline, aseptate, contents granular, smooth, thin-walled, oval, straight, rounded at the apex, or sometimes with truncate bases, becoming brown and septate when aged, without longitudinal striations or mucilaginous sheath.

Culture characteristics: Conidia germinating on PDA within 12 h. Colonies are fast growing on PDA, reaching 90 mm diam. after 5–6 days at 20–23 °C. Sparse, aerial, filamentous, becoming dark brown to black after 2 weeks.

Material examined: Thailand, Chiang Mai Province, Amphoe Mae Taeng, Tambon Pa Pae, 19°06’32.6’’ N, 98°44’21.1’’ E, on dead twigs of Amygdalus sp. (Rosaceae), 8 August 2019, Na Wu, YW255 (MFLU 23-0014, holotype); ex-type living culture MFLUCC 23-0038; ibid., on an unidentified decaying wood, 7 August 2019, Na Wu, YW253 (MFLU 23-0013, paratype), living culture MFLUCC 23-0037.

Notes: The phylogenetic result showed that two isolates of Dothiorella rosacearum constitute a distinct lineage but claded closer to Do. brevicollis, Do. diospyricola, Do. lampangensis, Do. longicollis, Do. obovata and Do. tectonae. A comparison of ITS sequences data between Do. rosacearum and Do. tectonae showed that there are 19 bp of 539 base pairs differences (including the gaps). In addition, the shortly raised irregular striations can be found on the conidia of Do. tectonae, while no striations were observed in Do. rosacearum. Therefore, Do. rosacearum is a morphologically and phylogenetically distinct species and herein introduced as a new species.