UMR MICALIS, INRA, AgroParisTech, CBAI, Thiverval Grignon, France.
Appl Environ Microbiol. 2013 Feb;79(4):1200-11. doi: 10.1128/AEM.03259-12. Epub 2012 Dec 7.
Yarrowia lipolytica, located at the frontier of hemiascomycetous yeasts and fungi, is an excellent candidate for studies of metabolism evolution. This yeast, widely recognized for its technological applications, in particular produces volatile sulfur compounds (VSCs) that fully contribute to the flavor of smear cheese. We report here a relevant global vision of sulfur metabolism in Y. lipolytica based on a comparison between high- and low-sulfur source supplies (sulfate, methionine, or cystine) by combined approaches (transcriptomics, metabolite profiling, and VSC analysis). The strongest repression of the sulfate assimilation pathway was observed in the case of high methionine supply, together with a large accumulation of sulfur intermediates. A high sulfate supply seems to provoke considerable cellular stress via sulfite production, resulting in a decrease of the availability of the glutathione pathway's sulfur intermediates. The most limited effect was observed for the cystine supply, suggesting that the intracellular cysteine level is more controlled than that of methionine and sulfate. Using a combination of metabolomic profiling and genetic experiments, we revealed taurine and hypotaurine metabolism in yeast for the first time. On the basis of a phylogenetic study, we then demonstrated that this pathway was lost by some of the hemiascomycetous yeasts during evolution.
解脂耶氏酵母位于半子囊菌酵母和真菌的交界处，是研究代谢进化的绝佳候选生物。这种酵母因其技术应用而广为人知，特别是它能够产生挥发性硫化合物（VSCs），这些化合物对涂抹奶酪的风味有重要贡献。我们在此通过转录组学、代谢物分析和 VSC 分析等综合方法，报告了 Yarrowia lipolytica 中基于高硫和低硫源（硫酸盐、蛋氨酸或胱氨酸）供应的硫代谢的相关整体情况。在高蛋氨酸供应的情况下，硫酸盐同化途径受到最强的抑制，同时硫中间产物大量积累。高硫酸盐供应似乎通过亚硫酸盐的产生引起了相当大的细胞应激，导致谷胱甘肽途径的硫中间产物的可用性降低。对于胱氨酸供应，观察到的影响最小，这表明细胞内半胱氨酸水平的控制比蛋氨酸和硫酸盐更为严格。我们使用代谢组学分析和遗传实验的组合，首次在酵母中揭示了牛磺酸和羟乙磺酸的代谢。基于系统发育研究，我们随后证明在进化过程中，一些半子囊菌酵母丢失了这条途径。
