Scheffersomyces jinghongensis C.Y. Chai & F.L. Hui, 2020

Jia, Ran-Ran, Lv, Shi-Long, Chai, Chun-Yue & Hui, Feng-Li, 2020, Three new Scheffersomyces species associated with insects and rotting wood in China, MycoKeys 71, pp. 87-99 : 91

Scheffersomyces jinghongensis C.Y. Chai & F.L. Hui sp. nov. Figure 2

Etymology.

The species name jinghongensis (N.L. fem. adj.) refers to the geographical origin of the type strain of this species.

Holotype.

NYNU 17926T.

Isolation data.

China, Yunnan Province, Jinghong, in rotting wood, under a tropical rainforest, July 2017, K.F. Liu & Z.W. Xi (ex-holotype: CICC 33270; CBS 15230).

Description.

The cells are ovoid to elongate (3-4 × 3-7.5 μm) and occur singly or in pairs after being placed in YM broth for 3 days at 25 °C (Fig. 2A ). Budding is multilateral. After 3 days of growth on YM agar at 25 °C, the colonies are white to cream-colored, buttery, and smooth, with entire margins. After 7 days at 25 °C on a Dalmau plate culture with CM agar, pseudohyphae were observed but true hyphae were not (Fig. 2B ). Asci or signs of conjugation were not observed on sporulation media. Glucose, galactose, trehalose, cellobiose, and d-xylose (weak) are fermented, but maltose, sucrose, melibiose, lactose, melezitose, raffinose, and inulin are not. Glucose, galactose, l-sorbose, d-glucosamine, d-ribose, d-xylose, sucrose, maltose, trehalose, cellobiose, arbutin, melezitose, inulin, glycerol, erythritol, ribitol, xylitol, d-glucitol, d-mannitol, d-glucono-1, 5-lactone, 2-keto-d-gluconate, d-glucuronate, succinate, and ethanol are assimilated. No growth was observed in l-arabinose, d-arabinose, l-rhamnose, methyl α-d-glucoside, salicin, melibiose, lactose, raffinose, l-arabinitol, galactitol, myo -inositol, 5-keto-d-gluconate, d-gluconate, dl-lactate, citrate, or methanol. For the assimilation of nitrogen compounds, growth on l-lysine, glucosamine, or d-tryptophan is positive, while growth on nitrate, nitrite, ethylamine, cadaverine, creatine, creatinine, or imidazole is negative. Growth is observed at 37 °C but not at 40 °C. Growth in the presence of 0.1% cycloheximide is positive, but growth in the presence of 10% NaCl with 5% glucose and 1% acetic acid is negative. Starch-like compounds are not produced. Urease activity and diazonium blue B reactions are also negative.

Additional isolate examined.

China, Yunnan Province, Jinghong, in rotting wood, under a tropical rainforest, July 2017, K.F. Liu & Z.W. Xi, NYNU 17977.

GenBank accession numbers.

holotype NYNU 17926T (ITS:MG255722; nrLSU D1/D2: MG255714); additional isolate NYNU 17977 (ITS: MT133547; nrLSU D1/D2: MT133543).

Notes.

Two strains representing S. jinghongensis were grouped in an independent lineage and are related to S. titanus and other Scheffersomyces species. The nucleotide differences between the new species and the close relative S. titanus ( Liu et al. 2016b) are 1.6% substitutions in the D1/D2 domain and 4.9% substitutions in the ITS region, respectively. Physiologically, S. jinghongensis can be differentiated from S. titanus based on growth in l-arabinose, l-rhamnose, methyl α-d-glucoside, salicin, lactose, myo -inositol, and 5-keto-d-gluconate, all of which were positive for S. titanus and negative for the new species. Additionally, S. jinghongensis ferments cellobiose and grows at 37 °C, but not for S. titanus .

Figures

Figure 2. Morphology of S. jinghongensis. A budding cells B pseudohyphae. Scale bars: 10 μm.