Derxomyces bifurcus 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 : 95

Derxomyces bifurcus Q.M. Wang, F.Y. Bai & A.H. Li sp. nov. MycoBank MB828776. Fig. 9M, N .

Etymology: the specific epithet bifurcus refers to the vegetative cells producing bifurcate budding of the type strain.

Culture characteristics: In YM broth, after 7 d at 17 °C, cells are cylindrical and ellipsoidal, 1.5–2.8 × 5.0– 8.3 μm and single, budding is bifurcate or multi-polar ( Fig. 9M ), a sediment is formed. After 1 mo at 17 °C, a ring and sediment are present. On YM agar, after 1 mo at 17 °C, the streak culture is yellowish-cream, butyrous, wrinkled and dull. The margin is entire or eroded. In Dalmau plate culture on corn meal agar, pseudohyphae are formed. Sexual structures are not observed on YM, PDA, V8 and CM agar. Ballistoconidia are are ellipsoidal to napiform, 3.0– 4.0 × 5.0– 6.6 μm ( Fig. 9N ).

Physiological and biochemical characteristics: Glucose fermentation is absent. Glucose, galactose, sucrose, maltose, cellobiose, trehalose, melibiose, raffinose, melezitose, inulin, soluble starch (weak), D-xylose, L-arabinose, D-arabinose, D-ribose and L-rhamnose are assimilated as sole carbon sources. L-sorbose, lactose, D-glucosamine, N-Acetyl-D-glucosamine, methanol, ethanol, glycerol, erythritol, ribitol, galactitol, D-mannitol, D-glucitol, Methyl-α- D-glucoside, salicin, 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 28 °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, De. bifurcus differs from its closely related species De. napiformis in its inability to assimilate Methyl-α- Dglucoside, succinate and myo-inositol and its ability to assimilate inulin, D-ribose and potassium nitrate ( Table S1.11 ).

Typus: China, Simao county, Yunnan province, obtained from a leaf of an unidentified plant, Nov. 2006, Q.-M. Wang (holotype CGMCC 2.3470 T preserved in a metabolically inactive state, ex-type CBS 15489 = SM37.5).

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.