Derxomyces xingshanicus 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 : 94

Derxomyces xingshanicus Q.M. Wang, F.Y. Bai & A.H. Li sp. nov. MycoBank MB828772. Fig. 9E, F .

Etymology: the specific epithet xingshanicus refers to the geographic origin of the type strain, Xingshan county, Hubei.

Culture characteristics: In YM broth, after 7 d at 17 °C, cells are ellipsoidal and cylindrical, 2.0– 5.0 × 5.5–11.2 μm and single, budding is polar ( Fig. 9E ), a sediment is present. After 1 mo at 17 °C, a ring and a sediment are present. On YM agar, after 1 mo at 17 °C, the streak culture is yellow, butyrous, smooth and semi-glossy. The margin is entire. In Dalmau plate culture on corn meal agar, pseudohyphae and hyphae are formed. Sexual structures are not observed on YM, PDA, V8 and CM agar. Ballistoconidia are are ellipsoidal to napiform, 3.0–6.2 × 5.5– 8.0 μm ( Fig. 9F ).

Physiological and biochemical characteristics: Glucose fermentation is absent. Glucose, galactose, sucrose, maltose, cellobiose, trehalose, melibiose, raffinose, melezitose, inulin (weak), soluble starch (weak), D-xylose, L-arabinose, D-arabinose, Dribose, L-rhamnose, D-glucosamine (weak), erythritol, galactitol, D-mannitol, D-glucitol, Methyl-α- D-glucoside, salicin, DL-lactate, succinate (weak) and myo-inositol are assimilated as sole carbon sources. L-sorbose, lactose, methanol, ethanol, glycerol, ribitol, citrate and hexadecane are not assimilated. Ammonium sulfate, L-lysine, ethylamine hydrochloride and cadaverine dihydrochloride are assimilated as sole nitrogen sources. Potassium nitrate and sodium nitrite are not assimilated. Maximum growth temperature is 28 °C. Growth in vitamin-free medium is negative. Starch-like substances are produced. Growth on 50 % (w/w) glucose-yeast extract agar is negative. Urease activity is positive. Diazonium Blue B reaction is positive.

Physiologically, De. xingshanicus differs from the closely related species De. cylindricus in its inability to assimilate Lsorbose, ribitol and sodium nitrite and its ability to assimilate erythritol ( Table S1.11 ).

Typus: China, Xingshan county, Hubei province, obtained from a leaf of an unidentified plant, Jul. 2003, Q.-M. Wang (holotype CGMCC 2.2459 T preserved in a metabolically inactive state, ex-type CBS 15445 = HX16.1).

Figures

Fig. 9. 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) Bu. elongatum CGMCC 2.4428T; (B) De. pseudoboekhoutii CGMCC 2.4436T; (C, D) De. polymorphus CGMCC 2.4437T; (E, F) De. xingshaicus CGMCC 2.2459T; (G, H) De. pseudoyunnanensis CGMCC 2.3563T; (I, J) De. longiovatus CGMCC 2.3535T; (K, L) De. napiformis CGMCC 2.4446T; (M, N) De. bifurcus CGMCC 2.3470T; (O, P) De. elongatus CGMCC 2.3561T. Bars = 10 μm.