Fonsecazyma quercina sp. nov., a novel yeast species isolated from Persian oak (Quercus brantii) branch in Iran

A taxonomic study of yeast isolates collected from the Persian oak (Quercus brantii) branch in the Zagros oak forests (Kermanshah Province, West of Iran) revealed the presence of a novel yeast species. Morphological and physiological characteristics, as well as sequence analysis of the D1/D2 region of the large subunit rRNA gene and the internal transcribed spacer region, showed that, the novel species belonged to the genus Fonsecazyma (Tremellales, Bulleraceae). The name Fonsecazyma quercina sp. nov. is proposed for this new species. This novel species has the highest sequence similarity with Fonsecazyma sp. KT301 (97.58%). This isolate comprises spherical single cells and can grow in NaCl concentrations up to 1 M. It can thrive at pH levels of 4, 8, and 10 but not at a pH of 2. The isolate is psychrotolerant, exhibiting optimal growth between 6 and 25 °C but unable to grow outside of this temperature range. Regarding carbon sources, the isolate efficiently utilizes and assimilates glucose and trehalose. It also can utilize sucrose, mannose, maltose, and fructose to some extent but shows weak utilization of cellobiose, sorbitol, and rhamnose. However, this isolate cannot utilize galactose, sorbose, lactose, melibiose, arabinose, ribose, or glycine as sole carbon sources. The holotype of Fonsecazyma quercina sp. nov. was deposited at the Fungus Reference Collection of Herbarium Ministerii Iranici Agriculturae (IRAN) as an inactive form.