Derxomyces polymorphus 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 : 93-94

Derxomyces polymorphus Q.M. Wang, F.Y. Bai & A.H. Li sp. nov. MycoBank MB828771. Fig. 9C, D .

Etymology: the specific epithet polymorphus refers to the variable vegetative cell morphology of the type strain.

Culture characteristics: In YM broth, after 7 d at 17 °C, cells are ovoid to fusiform, 2.0– 4.8 × 4.7– 8.0 μm and single, budding is polar ( Fig. 9C ), 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 yellowish-cream, smooth and dull. 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 subglobosal to napiform, 3.0 –4.3 × 4.3–5.7 μm ( Fig. 9D ).

Physiological and biochemical characteristics: Glucose fermentation is absent. Glucose, galactose, sucrose, maltose, cellobiose, trehalose, melibiose, raffinose, melezitose, inulin (weak), soluble starch, D-xylose, L-rhamnose (weak), galactitol, D-glucitol, salicin (weak) and succinate are assimilated as sole carbon sources. L-sorbose, lactose, L-arabinose, D-arabinose, D-ribose, D-glucosamine, N-Acetyl-D-glucosamine, methanol, ethanol, glycerol, erythritol, ribitol, D-mannitol, Methyl-α- D-glucoside, DLlactate, citrate, myo-inositol and hexadecane are not assimilated. Ammonium sulfate, potassium nitrate (weak), L-lysine, ethylamine hydrochloride, cadaverine dihydrochloride are assimilated as sole nitrogen sources. Sodium nitrite is not assimilated. Maximum growth temperature is 27–28 °C. Growth in vitamin-free medium is weak. 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. polymorphus differs from the closely related species De. nakasei in its inability to assimilate L-sorbose, L-arabinose, D-arabinose, D-ribose, D-glucosamine, erythritol, D-mannitol, Methyl-α- D-glucoside, DL-lactate and myo-inositol ( Table S1.11 ).

Typus: China, Fuzhou county, Fujian province, obtained from a leaf of an unidentified plant, Aug. 2011, Q.-M. Wang (holotype CGMCC 2.4437 T preserved in a metabolically inactive state, ex-type CBS 15512 = FJYZ12-13).

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.