Cyberlindnera basumtsoensis L. Tian, Y. Y. Zheng, D. Phurbu & Q. M. Wang, 2025

Tian, Lin, Phurbu, Dorji & Zheng, Yan-Yan, 2025, Microbotryozyma lacustris sp. nov. (Basidiomycota, Ustilentylomataceae) and Cyberlindnera basumtsoensis sp. nov. (Ascomycota, Phaffomycetaceae), two novel yeasts isolated from freshwater Lake Basom Tso, China, MycoKeys 126, pp. 135-150 : 135-150

Cyberlindnera basumtsoensis L. Tian, Y. Y. Zheng, D. Phurbu & Q. M. Wang sp. nov.

Fig. 4

Etymology.

The species is named after the place where the type strain was isolated.

Holotype.

China • Xizang Autonomous Region, Nyingchi City, Gongbo’gyamda County, Basom Lake , from freshwater, GPS: 30°02'11"N, 93°78'53"E, 3440 m a. s. l., on 15 August 2023, Y. Y. Zheng, ( holotype CGMCC 2.8853 T permanently preserved in a metabolically inactive state, ex-holotype JCM 10419 = ZYY 005 ) .

Description.

Culture characteristics: After 3 days of incubation in YM broth at 17 ° C, cells were ellipsoidal to ovoid, measuring 2.6–3.7 × 3.0–5.5 µm, and reproduced by monopolar budding (Fig. 4 ). After one month under the same conditions, conspicuous rings and sediment were present. On YM agar at 17 ° C for 3 days, colonies were creamy-white, butyrous, and emitted a characteristic aroma; the center was slightly raised and produced filaments when lifted with a loop. Pseudohyphae were not formed on cornmeal agar. No ascospores or sexual structures were observed on YM, PDA, V 8, or cornmeal agar after 6 weeks. Ballistoconidia were not produced. Physiological and biochemical characteristics: D-Glucose, sucrose, melibiose, raffinose, melezitose, inulin, soluble starch, L-rhamnose, ethanol, glycerol, galactitol, D-mannitol, D-glucitol, DL-lactic acid, and succinic acid were assimilated. D-Galactose, maltose, cellobiose, and citric acid were assimilated weakly or after a delay. L-Sorbose, trehalose, lactose, L-arabinose, D-arabinose, D-ribose, N-acetyl-D-glucosamine, methanol, erythritol, ribitol, α-methyl-D-glucoside, inositol, and hexadecane were not assimilated. Cadaverine dihydrochloride, L-lysine (weakly), and potassium nitrate (weakly) were utilized as sole nitrogen sources; ammonium sulfate, sodium nitrite, and ethylamine hydrochloride were not utilized. Starch-like compounds were not produced. Growth in vitamin-free medium was weak. No growth occurred on 50 % (w / w) glucose – yeast extract agar.

Materials examined.

China • Qinghai Province, Golog Tibetan Autonomous Prefecture, Jiuzhi County, County Road X 740 , isolated from a plant, GPS: 33°62'81"N, 101°54'60"E, 3525.7 m a. s. l., on 18 September 2025 (living culture Y-18-1-13-6 ) .

Notes.

Strains CGMCC 2.8853 T and Y-18-1-13-6 represent a novel species within the genus Cyberlindnera , for which we propose the name C. basumtsoensis . The type strain CGMCC 2.8853 showed significant genetic divergence from its closest phylogenetic neighbors, with sequence disparities of 10.22 % in the D 1 / D 2 domain and 15.66 % in the ITS region, unequivocally supporting its status as a distinct species. Phenotypically, C. basumtsoensis exhibits a distinctive combination of traits, including weak assimilation of D-galactose, delayed assimilation of raffinose and inulin, weak utilization of potassium nitrate and L-lysine, and an inability to assimilate trehalose or ethylamine hydrochloride (Table 4). These characteristics provide a clear phenotypic signature that differentiates it from other described Cyberlindnera species.

Figures

Figure 4. Morphology of C. basumtsoensis sp. nov. (strain CGMCC 2.8853 T). A. Individual colonies by streaking onto Potato Dextrose Agar (PDA) after 3 days; B. Cylindrical arthroconidia on yeast extract – malt extract (YM) after three days of growth at 17 ° C. Scale bars: 10 μm.