Robertozyma xinjiangensis C. Y. Chai & F. L. Hui sp. nov.

Fig. 4

Etymology.

The specific epithet xinjiangensis refers to the geographic origin of the ex-type strain, Wulumuqi City, Xinjiang Uygur Autonomous Region.

Typus.

China • Xinjiang Uygur Autonomous Region, Wulumuqi City, Tianshan Mountains, on the phylloplane of Ulmus pumila, July 2024, Z. W. Xi, NYNU 24728 (holotype GDMCC 2.525 T preserved in a metabolically inactive state, metabolically inactive ex-type culture PYCC 10132).

Description.

On YM agar after 7 days at 20 ° C, streak cultures are pale yellow, smooth and butyrous, and the margin is entire. In YM broth after 3 days at 20 ° C, cells are oval and ellipsoidal (4.5–5.9 × 5.9–7.8 µm) and occur singly or in pairs. Budding is polar. After a month in YM broth at 20 ° C, a sediment and a ring are formed. In Dalmau plate culture on CMA at 20 ° C, pseudohyphae and hyphae are absent. Sexual structures are not observed on PDA, CMA or V 8 agar at 17 ° C. Ballistoconidia are not produced. Glucose fermentation is absent. The following carbon sources are assimilated: glucose, inulin (delayed), trehalose, salicin (weak and delayed), D-arabinose, 5 - keto-D-gluconate, glycerol, ribitol, D-mannitol, succinate, and D-gluconate (weak and delayed). Sucrose, raffinose, melibiose, D-galactose, lactose, maltose, melezitose, methyl-α-D-glucoside, cellobiose, L-sorbose, L-rhamnose, D-xylose, L-arabinose, D-ribose, methanol, ethanol, erythritol, galactitol, D-glucitol, myo - inositol, DL-lactate, citrate, D-glucosamine, N-acetyl-D-glucosamine, 2 - keto-D-gluconate, D-glucuronate, and D-glucono- 1, 5 - lactone are not assimilated. L-Lysine is assimilated as sole nitrogen sources. Nitrate, nitrite, ethylamine, and cadaverine are not assimilated. Growth is observed at 25 ° C, but not at 30 ° C. Growth on 50 % (w / w) glucose-yeast extract agar is negative. Urease activity and diazonium blue B reaction are positive.

Additional strain examined.

China • Xinjiang Uygur Autonomous Region, Wulumuqi City, Tianshan Mountains, on the phylloplane of Ulmus pumila, July 2024, Z. W. Xi, NYNU 24739 and NYNU 24756.

GenBank accession numbers.

Holotype GDMCC 2.525 T (ITS: PQ 571078, LSU: PQ 571077, RPB 2: PZ 233422); additional strains NYNU 24739 (ITS: PX 712007, LSU: PX 712008) and NYNU 24756 (ITS: PX 712009, LSU: PX 712010, RPB 2: PZ 233423).

Note.

Physiologically, R. xinjiangensis differs from the closely related species R. ningxiaensis in its ability to assimilate inulin, ribitol, and D-gluconate and its inability to assimilate galactose. Furthermore, R. xinjiangensis is able to grow at 25 ° C, whereas R. ningxiaensis does not exhibit growth at this temperature (Table 2).