Spathaspora mengyangensis 2020

Spathaspora mengyangensis C.Y. Chai & F.L. Hui, sp. nov.2020

MycoBank 836445

Holotype: China, Yunnan Province, Jinghong City, Mengyang Town, in rotting wood from a tropical rainforest, July 2017, K.F. Liu & L. Zhang (holotype, NYNU 17741T preserved in a metabolically-inactive state), ex-holotype: CICC 33267; CBS 15227.

Morphological description:

In YM broth after 3 days at 25 °C, cells are ovoid (3–7 × 5–7.5 μm) and occur singly or in pairs (Fig. 3a). 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 14 days at 25 °C on Dalmau plate culture on CM agar, pseudohyphae are present, but true hyphae are not formed (Fig. 3b). Sporulation occurs on CM agar after 14 days at 25 °C. Unconjugated asci are formed from single cells with one elongated ascospore which are tapered and curved at the ends (Fig. 3c). Xylose fermentation is negative using Durham tubes, but ethanol is produced from xylose when determined with alcohol oxidase and peroxidase tests. Glucose, d-ribose, d-xylose, sucrose, maltose, trehalose, methyl α-d-glucoside, cellobiose, salicin, arbutin, inulin, ribitol, d-glucitol, d-mannitol, 2-keto-d-gluconate, succinate and ethanol are assimilated. No growth occurs with galactose, l-sorbose, d-glucosamine, l-arabinose, d-arabinose, l-rhamnose, melibiose, lactose, raffinose, melezitose, glycerol, erythritol, xylitol, galactitol, myo-inositol, dglucono-1, 5-lactone, 5-keto-d-gluconate, d-gluconate, d-glucuronate, dl-lactate, citrate 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 30 °C, but not at 35 °C. Growth in the presence of 10% NaCl plus 5% glucose, 0.01% cycloheximide and 1% acetic acid is absent. Starch-like compounds are not produced. 

Urease activity and diazonium blue B reactions are negative.

Habitat: in rotting wood from a tropical rainforest 

Distribution: China 

GenBank Accession: Strain NYNU17705 ITSMT272353  D1/D2 MT272351

Notes:Phylogenetic analyses show that Sp. mengyangensis is closely related to Sp. elongata and C. subhashii; however, the independent phylogenetic position and different physiological characters can distinguish Sp. mengyangensis from its sister species Sp. elongata (as mentioned above). Similarly, Sp. mengyangensis differed from C. subhashii by 2.8% substitutions in the D1/D2 domain and 7.8% substitutions in the ITS region (Groenewald et al. 2016). Physiologically, Sp. mengyangensis can be differentiated from C. subhashii by the ability to assimilate d-ribose, trehalose, d-glucitol and d-mannitol and the inability to assimilate galactose, l-arabinose and melezitose. In addition, C. subhashii can grow at 40 °C, but Sp. mengyangensis cannot.

Reference: Lv S-L, Chai C-Y, Wang Y, Yan Z-L, Hui F-L (2020) Five new additions to the genus Spathaspora (Saccharomycetales, Debaryomycetaceae) from southwest China. MycoKeys 75: 31–49. https://doi.org/10.3897/ mycokeys.75.57192

Figure 3. Spathaspora mengyangensis (NYNU 17741, holotype) a budding cells on YM broth after 3 d b simple pseudohyphae on CM agar after 14 d c ascus and ascospore (arrow) on CM agar after 14 d. Scale bars: 10 μm.