The novel extremophilic yeast Rhodotorula frigidialcoholis, formerly R. JG1b, was isolated from ice-cemented permafrost in University Valley (Antarctic), one of coldest and driest environments on Earth. Phenotypic and phylogenetic analyses classified R. frigidialcoholis as a novel species. To characterize its cold-adaptive strategies, we performed mRNA and sRNA transcriptomic analyses, phenotypic profiling, and assessed ethanol production at 0 and 23 °C. Downregulation of the ETC and citrate cycle genes, overexpression of fermentation and pentose phosphate pathways genes, growth without reduction of tetrazolium dye, and our discovery of ethanol production at 0 °C indicate that R. frigidialcoholis induces a metabolic switch from respiration to ethanol fermentation as adaptation in Antarctic permafrost. This is the first report of microbial ethanol fermentation utilized as the major energy pathway in response to cold and the coldest temperature reported for natural ethanol production. R. frigidialcoholis increased its diversity and abundance of sRNAs when grown at 0 versus 23 °C. This was consistent with increase in transcription of Dicer, a key protein for sRNA processing. Our results strongly imply that post-transcriptional regulation of gene expression and mRNA silencing may be a novel evolutionary fungal adaptation in the cryosphere.

新型极端嗜热酵母冷红酵母（Rhodotorula frigidialcoholis） ，以前称为R . JG1b是从大学谷（南极洲）的冰冻永久冻土中分离出来的，那里是地球上最冷和最干燥的环境之一。表型和系统发育分析将R. frigidialcoholis归类为一个新物种。为了表征其冷适应策略，我们进行了 mRNA 和 sRNA 转录组分析、表型分析，并评估了 0 和 23 °C 下的乙醇产量。 ETC 和柠檬酸循环基因的下调、发酵和磷酸戊糖途径基因的过度表达、四唑染料不还原的生长以及我们在 0 °C 下生产乙醇的发现表明，冷菌诱导从呼吸到乙醇发酵的代谢转换，如下所示：南极永久冻土的适应。这是首次报道微生物乙醇发酵被用作应对寒冷和天然乙醇生产报道的最冷温度的主要能量途径。罗。冷乙醇在 0 与 23 °C 下生长时，其 sRNA 的多样性和丰度有所增加。这与 Dicer 转录的增加一致，Dicer 是 sRNA 加工的关键蛋白。我们的结果强烈暗示基因表达的转录后调控和 mRNA 沉默可能是冰冻圈中真菌的一种新的进化适应。