Spathaspora rosae C.Y. Chai & F.L. Hui, 2020

Lv, Shi-Long, Chai, Chun-Yue, Wang, Yun, Yan, Zhen-Li & Hui, Feng-Li, 2020, Five new additions to the genus Spathaspora (Saccharomycetales, Debaryomycetaceae) from southwest China, MycoKeys 75, pp. 31-49 : 31

Spathaspora rosae C.Y. Chai & F.L. Hui sp. nov. Figure 6

Type.

China, Yunnan Province, Jinghong City, Mengyang Town, in rotting wood in a tropical rainforest, July 2017, Z.W. Xi & L. Zhang (holotype, NYNU 17934T preserved in a metabolically-inactive state), ex-holotype: CICC 33271; CBS 15231.

Etymology.

Rosae was named in honour of Carlos A. Rosa for his contributions in yeast taxonomy.

Description.

In YM broth after 3 days at 25 °C, cells are ovoid to elongate (4-7 × 5-16 μm) and occur singly or in pairs (Fig. 6a ). Budding is multilateral. Sediment is formed after a month, but a pellicle is not observed. After 3 days of growth on YM agar at 25 °C, colonies are white to cream-coloured, butyrous and smooth with entire margins. After 7 days at 25 °C, on Dalmau plate culture on CM agar, pseudohyphae and true hyphae are formed (Fig. 6b ). Asci or signs of conjugation are not seen on sporulation media used. Xylose fermentation is negative using Durham tubes, but ethanol is produced from xylose when determined with alcohol oxidase and peroxidase tests. Glucose, d-glucosamine, d-xylose, sucrose, maltose, trehalose, methyl α-d-glucoside, cellobiose, salicin, arbutin, inulin, ribitol, d-glucitol, d-mannitol, 2-keto-d-gluconate, dl-lactate, succinate, citrate and ethanol are assimilated. No growth occurs with galactose, l-sorbose, d-ribose, l-arabinose, d-arabinose, l-rhamnose, melibiose, lactose, raffinose, melezitose, glycerol, erythritol, xylitol, galactitol, myo -inositol, d-glucono-1, 5-lactone, 5-keto-d-gluconate, d-gluconate, d-glucuronate, l-arabinitol or methanol. For the assimilation of nitrogen compounds, growth on ethylamine, l-lysine, glucosamine or d-tryptophan is present, whereas growth on nitrate, nitrite, cadaverine, creatine, creatinine or imidazole is absent. Growth is observed at 35 °C, but not at 37 °C. Growth in the presence of 0.01% cycloheximide is present, but growth in the presence of 0.1% cycloheximide, 10% NaCl plus 5% glucose and 1% acetic acid is absent. Starch-like compounds are not produced. Urease activity and diazonium blue B reactions are negative.

Additional isolates examined.

China, Yunnan Province, Jinghong City, Mengyang Town, in rotting wood in a tropical rainforest, July 2017, Z.W. Xi & L. Zhang NYNU 17903, NYNU 17909.

Notes.

Three strains, representing Sp. rosae , grouped in a well-supported clade and appear to be most closely related to Sp. allomyrinae ( Wang et al. 2016). The nucleotide differences between Sp. rosae and its close relative, Sp. allomyrinae , were 10.2% substitutions in the D1/D2 domain and 11% substitutions in the ITS region ( Groenewald et al. 2016). Physiologically, Sp. rosae can be differentiated from Sp. allomyrinae , based on growth in galactose, melezitose, xylitol and 5-keto-d-gluconate, which are positive for Sp. allomyrinae and negative for Sp. rosae . Moreover, Sp. allomyrinae weakly ferments glucose, galactose, maltose and cellobiose, but Sp. rosae does not.

Figures

Figure 6. Morphology of Spathaspora rosae (NYNU 17934, holotype) a budding cells and elongated vegetative cells on YM broth after 3 d b true hyphae with blastoconidia on CM agar after 14 d. Scale bars: 10 μm.