Spathaspora jiuxiensis 2020

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

MycoBank 836446

Holotype: China, Yunnan Province, Honghe Prefecture, Luxi County, in rotting wood in Jiuxi Mountain Forest Park, July 2017, K.F. Liu & L. Zhang (holotype, NYNU 17416T preserved in a metabolically-inactive state), ex-holotype: CICC 33264; CBS 15226.

Morphological description:

In YM broth after 3 days at 25 °C, cells are ovoid to elongate (3–6 × 3.5–9 μm) and occur singly or in pairs (Fig. 4a); pseudohyphae are present. 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 12 days at 25 °C on Dalmau plate culture on CM agar, pseudohyphae and true hyphae are formed (Fig. 4b). Asci or signs of conjugation were not seen on the sporulation media used. Glucose and maltose are weakly fermented. 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-ribose, d-xylose, sucrose, maltose, trehalose, methyl α-dglucoside, cellobiose, salicin, arbutin, melezitose, inulin, ribitol, d-glucitol, d-mannitol, 2-keto-d-gluconate, dl-lactate, succinate and ethanol are assimilated. No growth occurs with galactose, l-sorbose, l-arabinose, d-arabinose, l-rhamnose, melibiose, lactose, raffinose, glycerol, erythritol, xylitol, galactitol, myo-inositol, d-glucono-1, 5-lactone, 5-keto-d-gluconate, d-gluconate, d-glucuronate, citrate, l-arabinitol or methanol. For the assimilation of nitrogen compounds, growth on l-lysine, glucosamine or d-tryptophan is present, whereas growth on nitrate, nitrite, ethylamine, 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.

Habitat: in rotting wood from a tropical rainforest 

Distribution: China 

GenBank Accession: Strain   NYNU 17417\NYNU 17416 T  ITSMT276035\MG255706  D1/D2 MT276032\MG255718

Notes: The two strains, both representing Sp. jiuxiensis, cluster in a well-supported clade in the phylogenetic analysis and are closely related to Sp. parajiuxiensis. The nucleotide differences between these two new species were 1.4% substitutions in the D1/D2 domain and 4.6% substitutions in the ITS region (Groenewald et al. 2016). These two sister species can also be differentiated by a few physiological characteristics; Sp. jiuxiensis can assimilate dl-lactate and Sp. parajiuxiensis can grow at 37 °C.

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 4. Morphology of Spathaspora jiuxiensis (NYNU 17416, holotype) a budding cells and pseudohyphae on YM broth after 3 d b true hyphae with blastoconidia on CM agar after 14 d. Scale bars: 10 μm.