Stress tolerance is a desired characteristic of yeast strains for industrial applications. Stress tolerance has been well described in Saccharomyces yeasts but has not yet been characterized in oleaginous Rhodotorula yeasts even though they are considered promising platforms for lipid production owing to their outstanding lipogenicity. In a previous study, the thermotolerant strain L1–1 was isolated from R. toruloides DMKU3-TK16 (formerly Rhodosporidium toruloides). In this study, we aimed to further examine the ability of this strain to tolerate other stresses and its lipid productivity under various stress conditions. We found that the L1–1 strain could tolerate not only thermal stress but also oxidative stress (ethanol and H₂O₂), osmotic stress (glucose) and a cell membrane disturbing reagent (DMSO). Our results also showed that the L1–1 strain exhibited enhanced ability to maintain ROS homeostasis, stronger cell wall strength and increased levels of unsaturated membrane lipids under various stresses. Moreover, we also demonstrated that ethanol-induced stress significantly increased the lipid productivity of the thermotolerant L1–1. The thermotolerant L1–1 was also found to produce a higher lipid titer under the dual ethanol-H₂O₂ stress than under non-stress conditions. This is the first report to indicate that ethanol stress can induce lipid production in an R. toruloides thermotolerant strain.

中文翻译：

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乙醇和H2O2胁迫增强了油质Rhodotorula toruloides耐热突变体L1-1中的脂质产生。

压力耐受性是用于工业应用的酵母菌株的期望特征。在酿酒酵母中已经很好地描述了胁迫耐受性，但是在油性红球酵母中还没有表征出其耐受性，尽管由于其出色的脂肪原性而被认为是生产脂质的有前途的平台。在先前的研究中，耐热的应变L1-1从分离R.孢酵母DMKU3-TK16（原红冬孢酵母）。在这项研究中，我们旨在进一步研究该菌株在各种胁迫条件下耐受其他胁迫的能力及其脂类生产力。我们发现，L1-1菌株不仅可以耐受热胁迫，还可以耐受氧化胁迫（乙醇和氢₂ O ₂），渗透压（葡萄糖）和细胞膜干扰剂（DMSO）。我们的结果还表明，在各种压力下，L1-1菌株显示出增强的维持ROS稳态，增强细胞壁强度和增加不饱和膜脂质水平的能力。此外，我们还证明了乙醇诱导的应激显着提高了耐热L1-1的脂质生产率。还发现耐热L1-1在双重乙醇-H ₂ O ₂胁迫下比在非胁迫条件下产生更高的脂质效价。这是第一个表明乙醇胁迫可以诱导拟南芥耐热菌株中脂质产生的报告。