Filobasidium castaneae C. Y. Cai & F. L. Hui sp. nov.

Fig. 3 B

Etymology.

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

Typus.

China • Henan Province, Nanyang City, Baotianman Nature Reserve, in the phylloplane of Castanea mollissima, November 2021, R. R. Jia and W. T. Hu, NYNU 2111105 (holotype CICC 33541 T preserved in a metabolically inactive state in the China Centre of Industrial Culture Collection, culture ex-type JCM 35729 deposited in the Japan Collection of Microorganisms).

Description.

On YM agar, after 7 days at 20 ° C, the streak culture is gray-cream, mucoid, smooth, and glossy. The margin is entire. On YM agar, after 7 days at 20 ° C, cells are globosal and ellipsoidal, 3.6–5.8 × 4.2–7.1 μm, and single, budding is polar. After 1 month at 20 ° C, a ring and sediment are present. In Dalmau plate culture on corn meal agar, pseudohyphae are not formed. Sexual structures are not observed on PDA, CM agar, and YCBS agar for two months. Ballistoconidia are not produced. Glucose fermentation is absent. Glucose, inulin, sucrose, raffinose, melibiose, galactose, lactose, trehalose, maltose, melezitose, methyl-α-D-glucoside, cellobiose, salicin, L-sorbose, L-rhamnose, D-xylose, L-arabinose, 5 - keto-D-gluconate, D-ribose, glycerol, ribitol, galactitol, D-mannitol, D-glucitol, myo-inositol, succinate, citrate, D-gluconate, N-acetyl-D-glucosamine, 2 - keto-D-gluconate, D-glucuronate, and glucono- 1, 5 - lactone are assimilated as sole carbon sources. D-Arabinose, methanol, ethanol, erythritol, DL-lactate, and D-glucosamine are not assimilated. Nitrate, nitrite, ethylamine, and L-lysine are assimilated as sole nitrogen sources. Cadaverine is not assimilated. Maximum growth temperature is 25 ° C. Growth in vitamin-free medium is positive. Growth on 50 % (w / w) glucose-yeast extract agar is negative. Starch-like substances are not produced. Urease activity is positive. Diazonium Blue B reaction is positive.

Additional strain examined.

China • Guizhou Province, Buyi and Miao Autonomous Prefecture of Qian Nan, Pingtang County, in the phylloplane of Mussaenda pubescens, February 2023, D. Lu, NYNU 23230 and NYNU 23245.

GenBank accession numbers.

Holotype CICC 33541 T (ITS: OM 049430, D 1 / D 2: OM 049431); additional strains NYNU 23230 (ITS: PP 114094, D 1 / D 2: PP 114092) and NYNU 23245 (ITS: PP 114096, D 1 / D 2: PP 114097).

Note.

Filobasidium castaneae sp. nov. can be physiologically distinguished from its closely related species F. globosum, F. mali, and F. pseudomali sp. nov. through its ability to assimilate D-ribose and glycerol (Table 3).