Rosettozyma motuoensis 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 : 119-121

Rosettozyma motuoensis Q.M. Wang, F.Y. Bai & A.H. Li sp. nov. MycoBank MB828834. Figs 16E, F and 17C .

Etymology: the specific epithet motuoensis refers to the geographic origin of the type strain, Motuo, Tibet.

Culture characteristics: In YM broth, after 7 d at 17 °C, cells are ellipsoidal, either singly or in rosettes, 1.5– 2.5 × 12.5– 20.0 μm, budding is polar ( Fig. 16E ), 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 white, butyrous, smooth, 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, 1.4– 2.3 × 11.7– 21.0 μm ( Fig. 16F ).

Physiological and biochemical characteristics: Glucose fermentation is absent. Glucose, sucrose, maltose, trehalose, melezitose, ethanol, D-mannitol, D-glucitol, Methyl-α- D-glucoside and succinate are assimilated as sole carbon sources. Galactose, Lsorbose, cellobiose, lactose, melibiose, raffinose, inulin, soluble starch, D-xylose, L-arabinose, D-arabinose, D-ribose, L- rhamnose, D-glucosamine, N-Acetyl-D-glucosamine, methanol, glycerol, erythritol, ribitol, galactitol, salicin, D-gluconate, DLlactate, citrate, myo-inositol and hexadecane are not assimilated. Ammonium sulfate, potassium nitrate, L-lysine and ethylamine hydrochloride are assimilated as sole nitrogen sources. Sodium nitrite and cadaverine dihydrochloride are not assimilated. Maximum growth temperature is 22– 23 °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. motuoensis and their two closely related species, Ro. petaloides and Ro. cystopteridis , can be distinguished from one another by the assimilation of D-xylose, L-arabinose, Darabinose, glycerol and succinate. Ro. motuoensis differs from Ro. petaloides in its inability to assimilate D-xylose, L-arabinose and glycerol and its ability to assimilate succinate. Ro. motuoensis differs from Ro. cystopteridis in its inability to assimilate D-arabinose and its ability to assimilate succinate ( Table S1.28 ).

Typus: China, Motuo , Tibet, obtained from a leaf of an unidentified plant, Sep. 2014, Q.-M. Wang (holotype CGMCC 2.5819 T preserved in a metabolically inactive state, ex-type CBS 15588 = XZ118E6).

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.