Yamadazyma luoyangensis2021

Yamadazyma luoyangensis C.Y. Chai & F.L. Hui, sp. nov.2021

MycoBank No: 840099

Holotype NYNU 201023

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Morphological description :

Asexual morph: The cells are ovoid to ellipsoid (2–4 × 3.5–7 µm) and occur singly or in pairs after being placed in YM broth for three days at 25 °C (Figure 2A). Budding is multilateral. After three days of growth on YM agar at 25 °C, the colonies are white to cream-colored, buttery, and smooth, with entire margins. After seven days at 25 °C on a Dalmau plate culture with CM agar, pseudohyphae are formed, but true hyphae are not (Figure 2B). Asci or signs of conjugation are not observed on sporulation media. Glucose, galactose, trehalose, and cellobiose are fermented, but maltose, sucrose, melibiose, lactose, melezitose, raffinose, d-xylose, and inulin are not. Glucose, galactose, d-glucosamine, d-ribose, d-xylose, l-arabinose, d-arabinose, l-rhamnose, sucrose, maltose, trehalose, methyl α-d-glucoside, cellobiose, salicin, arbutin, melezitose, inulin, glycerol, erythritol, ribitol, d-glucitol, d-mannitol, galactitol, d-glucono-1, 5-lactone, 5-keto-d-gluconate, d-gluconate, succinate, citrate, and ethanol are assimilated. No growth is observed in l-sorbose, melibiose, lactose, raffinose, myo-inositol, 2-keto-d-gluconate, d-glucuronate, dllactate, or methanol. In nitrogen-assimilation tests, growth is present on ethylamine, l-lysine, glucosamine, and d-tryptophan, while growth is absent on nitrate, nitrite, cadaverine, creatine, creatinine, and imidazole. Growth is observed at 35 °C but not at 37 °C. Growth in the presence of 10% NaCl with 5% glucose is present, but growth in the presence of 0.01% cycloheximide and 1% acetic acid is absent. Starch-like compounds are not produced. Urease activity and diazonium blue B reactions are negative.

sexual morph :not observed.

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Culture characteristics:

Habitat: ,in rotting wood from a forest park

Distribution: China, Henan Province, Luoyang City, Song County,

GenBank: Holotype NYNU 201023T (ITS: MW365549; D1/D2 LSU: MW365545); additional isolate NYNU 201035 (ITS: MZ318445; D1/ D2 LSU: MZ318422)

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Notes: Two isolates representing Y. luoyangensis were resolved in a well-supported clade and are most closely related to Y. mexicana (Figure 1). Yamadazyma luoyangensis can be distinguished from Y. mexicana based on ITS and D1/D2 LSU loci (4/592 in ITS and 10/531 in D1/D2 LSU). Physiologically, Y. luoyangensis differs from Y. mexicana by its ability to assimilate inulin and 5-keto-d-gluconate and its inability to assimilate lactose, raffinose, and 2-keto-d-gluconate. 

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Additionally, Y. mexicana grows at 37 °C, while Y. luoyangensis does not (Table 2) (Kurtzman 2011)

Reference: [1] Limkaisang, S.  Kom-Un, S. ,  Furtado, E. L. ,  Liew, K. W. ,   Salleh, B. , &  Sato, Y. , et al. (2005). Molecular phylogenetic and morphological analyses of oidium heveae, a powdery mildew of rubber tree. Mycoscience, 46(4), 220-226.

Yamadazyma luoyangensis (NYNU 201023, holotype) A budding cells after three days in YM broth at 25 °C B pseudohyphae on cornmeal agar after seven days at 25 °C. Scale bars: 10 µm.