Derxomyces alseodaphnes C. Y. Chai & F. L. Hui sp. nov.

Fig. 2

Etymology.

The specific epithet alseodaphnes refers to Alseodaphne, the plant genus from which the type strain was isolated.

Typus.

China • Hainan Prov.: Wuzhishan City, Wuzhi Mountain, on the phylloplane of Alseodaphne rugosa, August 2024, S. L. Lv, NYNU 24817 (holotype GDMCC 2.534 T preserved as a metabolically inactive state, culture ex-type JCM 38177).

Description.

On YM agar after 7 days at 20 ° C, the streak culture is pale-yellow, butyrous and smooth, with an entire margin. After 3 days in YM broth at 20 ° C, cells are ovoid and ellipsoidal, 2.1–4.0 × 2.6–4.9 μm and single, budding is polar. After 1 month at 20 ° C, a ring and sediment are present. In Dalmau plate culture on CMA, pseudohyphae and hyphae are not formed. Sexual structures are not observed on PDA, CMA or V 8 agar. Ballistoconidia are not produced. Glucose fermentation is absent. Glucose, inulin, sucrose, raffinose, melibiose, galactose, trehalose, maltose, melezitose, methyl-α-D-glucoside, cellobiose, salicin (weak), L-sorbose (delayed), L-rhamnose, D-xylose, L-arabinose, D-arabinose, 5 - keto-D-gluconate, D-ribose (delayed), erythritol (delayed), galactitol (delayed), D-mannitol, D-glucitol (delayed), myo-inositol (weak), DL-lactate, succinate (weak), citrate (weak and delayed), D-gluconate, D-glucosamine, N-acetyl-D-glucosamine, 2 - keto-D-gluconate, D-glucuronate and glucono- 1, 5 - lactone (weak) are assimilated as sole carbon sources. Lactose, methanol, ethanol, glycerol and ribitol are not assimilated. Ethylamine and L-lysine are assimilated as sole nitrogen sources. Nitrate, nitrite and cadaverine are not assimilated. Growth is observed on YM agar at 25 ° C, but not at 30 ° C. Growth on 50 % (w / w) glucose-yeast extract agar is negative. Growth in vitamin-free medium is positive. Starch-like substances are not produced. Urease activity is positive. Diazonium Blue B reaction is positive.

Additional strain examined.

China • Hainan Prov.: Wuzhishan City, Wuzhi Mountain, on the phylloplane of Polyalthia suberosa, August 2024, S. L. Lv, NYNU 2487.

GenBank accession numbers.

Holotype GDMCC 2.534 T (ITS: PQ 568969, D 1 / D 2: PQ 568968); additional strain NYNU 2487 (ITS: PV 404185, D 1 / D 2: PV 404184).

Note.

Physiologically, D. alseodaphnes can be distinguished from the closely-related species, D. hubeiensis, in its inability to assimilate ribitol and grow at 30 ° C, while being able to assimilate inulin and to grow in vitamin-free medium (Table 2).

Notes. 1, D. alseodaphnes; 2, D. hubeiensis; 3, D. henanensis; 4, D. pseudoschimicola; 5, D. melastomatis; 6, D. komagatae. +, positive reaction; –, negative reaction; d, delayed positive; s, slow positive; w, weakly positive. All data from this study, except * which were obtained from the original description (Wang and Bai 2008; Jiang et al. 2024).