Botryosphaeriales » Botryosphaeriaceae » Dothiorella

Dothiorella ovata

Dothiorella ovata N. Wu, A.J. Dissanayake & Jian K. Liu sp. nov. Figure 1.

Index Fungorum number: IF900578; Facesoffungi number: FoF14258.

Etymology: In reference to the ovoid conidia.

Holotype: MFLU 23-0009.

Saprobic on a dead wood. Sexual morph: Not observed. Asexual morph: Conidiomata 119–173 × 160–273 μm (x̅ = 141 × 204 μm, n = 20), semi-immersed or immersed in the substrate, emerging through the epidermis when mature, globose to subglobose, pyriform, dark brown, unilocular, solitary, glabrous, ostiolate. Ostiole 22–26 μm diam., single, circular, papillate, centrally located. Peridium up to 16–38 μm wide, comprising host and fungal tissues, thick-walled, dark brown to hyaline cells of textura angularis. Paraphyses absent. Conidiophores are reduced to conidiogenous cells. Conidiogenous cells 4–11 × 3–4 μm (x̅ = 7 × 4 μm, n = 20), hyaline, phialidic, cylindrical, straight or curved, smooth-walled. Conidia 20–26 × 9–11 μm (x̅ = 22 × 10 μm, n = 50), hyaline, aseptate, ovoid, rounded at both ends or sometimes with truncate bases, becoming pigmented brown and one septate at maturation, constricted in the middle, smooth-walled, 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, white in first few days, after 2 weeks, becoming black.

Material examined: Thailand, Chiang Mai Province, Amphoe Mae Taeng, Tambon Cho Lae, 19°08’01.3’’ N, 99°00’29.4’’ E, on an unidentified dead wood, 6 August 2019, Na Wu, YW177 (MFLU 23-0009, holotype); ex-type living culture MFLUCC 23-0035; ibid., 7 August 2019, Na Wu, YW231 (MFLU 23-0010, paratype), living culture MFLUCC 23-0036.

Notes: Dothiorella ovata is nested in between Do. albiziae, Do. septata and Do. thailandica but can be recognized as a distinct lineage. Morphologically, Do. ovata is similar to Do. septata and Do. albiziae, which in having oblong to ovoid, hyaline conidia becoming brown and one septate at maturation. However, Do. ovata differs from Do. septata and Do. albiziae by its slightly constricted septum and the larger conidia. In addition, a comparison of tef1-α sequences data of Do. ovata and Do. albiziae showed that there are 14 bp (base pair) differences (of 252 bp including the gaps), while Do. ovata and Do. thailandica showed 18 bp differences (of 302 bp including the gaps). Therefore, we introduce Do. ovata as a new species.

Figure 1. Dothiorella ovata (MFLU 23-0009, holotype). (a–c) Conidiomata on host substrate. (d) Vertical section of conidiomata. (e) Section of peridium. (f) Ostiolar region with periphyses. (g–j) Conidiogenous cells and developing conidia. (k–o) Conidia. (p) Germinated conidium. (q,r) Colonies on PDA, above (q) and below (r). Scale bars: (b,c) = 50 μm, (d,e) = 20 μm, (f) = 10 μm, (g,h) = 5 μm, (i–p) = 10 μm.

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