Rosettozyma cystopteridis Q.M. Wang, F.Y. Bai & A.H. Li, 2020

Li, A. - H., Yuan, F. - X., Groenewald, M., Bensch, K., Yurkov, A. M., Li, K., Han, P. - J., Guo, L. - D., Aime, M. C., Sampaio, J. P., Jindamorakot, S., Turchetti, B., Inacio, J., Fungsin, B., Wang, Q. - M. & Bai, F. - Y., 2020, Diversity and phylogeny of basidiomycetous yeasts from plant leaves and soil: Proposal of two new orders, three new families, eight new genera and one hundred and seven new species, Studies In Mycology 96, pp. 17-140 : 119

Rosettozyma cystopteridis Q.M. Wang, F.Y. Bai & A.H. Li sp. nov. MycoBank MB828833. Figs 16C, D and 17A, B .

Etymology: the specific epithet cystopteridis refers to Cystopteris , the plant genus from which the type strain was isolated.

Culture characteristics: In YM broth, after 7 d at 17 °C, cells are ellipsoidal, either singly or in rosettes, 2.2–2.8 × 11.4 –20.3 μm, budding is polar ( Fig. 16C ), a sediment is formed. After 1 mo at 17 °C, a pellicle and a sediment are present. On YM agar, after 1 mo at 17 °C, the streak culture is whitish to cream, butyrous, slightly wrinkle, semi-glistening. The margin is entire. In Dalmau plate culture on corn meal agar, pseudohyphae are not formed. Sexual structures are not observed on YM, PDA, V8 and CM agar. Ballistoconidia are allantoid or falcate, 1.7– 2.8 × 7.7– 15.4 μm ( Fig. 16D ).

Physiological and biochemical characteristics: Glucose fermentation is absent. Glucose, sucrose, maltose, trehalose, melezitose, L-arabinose (variable), D-arabinose, ethanol, erythritol (variable), D-mannitol, D-glucitol, Methyl-α- D-glucoside (variable) and salicin are assimilated as sole carbon sources. Galactose, L-sorbose, cellobiose, lactose, melibiose, raffinose, inulin, soluble starch, D-xylose, D-ribose, L-rhamnose, Dglucosamine, methanol, glycerol, ribitol, galactitol, DL-lactate, succinate, citrate, myo-inositol and hexadecane are not assimilated. Ammonium sulfate, potassium nitrate, L-lysine, ethylamine hydrochloride and cadaverine dihydrochloride are assimilated as sole nitrogen sources. Sodium nitrite is not assimilated. Maximum growth temperature is 27 °C. Growth in vitamin-free medium is negative. Starch-like substances are not produced. Growth on 50 % (w/w) glucose-yeast extract agar is negative. Urease activity is positive. Diazonium Blue B reaction is positive.

Physiologically, Ro. cystopteridis and its two closely related species, Ro. petaloides and Ro. motuoensis , can be distinguished from one another by the assimilation of D-xylose, Larabinose, D-arabinose, glycerol and succinate. Ro. cystopteridis differs from Ro. petaloides in its inability to assimilate D-xylose and glycerol. Ro. cystopteridis differs from Ro. motuoensis in its inability to assimilate succinate and its ability to assimilate Darabinose ( Table S1.28 ).

Typus: China, Bomi county, Tibet, obtained from a leaf of Cystopteris moupinensis, Sep. 2004 , F.-Y. Bai (holotype CGMCC 2.2615 T preserved in a metabolically inactive state, ex-type CBS 15448 = XZ16E1).

Figures

Fig. 16. Vegetative cells grown in YM broth for 5 d at 17 °C and ballistoconidia produced on corn meal agar after 7 d at 17 °C. (A, B) Ros. petaloides CGMCC 2.3446T; (C, D) Ros. cystopteridis CGMCC 2.2615T; (E, F) Ros. motuoensis CGMCC 2.5819T; (G, H) Sp. cellobiolyticus CGMCC 2.5675T; (I, J) Sp. reniformis CGMCC 2.5627T; (K, L) Sp. ellipsoideus CGMCC 2.5619T; (M, N) Sp. primogenomicus IAM13481T; (O, P) Rh. platycladi CGMCC 2.3118T. Bars = 10 μm.

Fig. 17. SEM image of vegetative cells grown in YM broth for 5 d at 17 °C. (A, B) Ros. cystopteridis CGMCC 2.2615T, A Bars = 10 μm, B Bars = 2 μm; (C) Ros. motuoensis CGMCC 2.5819T, Bars = 10 μm; (D) He. tridentata CGMCC 2.5602T, Bars = 10 μm; (E, F) He. cylindrica CGMCC 2.5650T, E Bars = 20 μm, F Bars = 5 μm; (G) Ya. terricola CGMCC 2.5820T, Bars = 10 μm; (H) Ch. rhododendri CGMCC 2.5821T, Bars = 5 μm.