Enhancement of sphingolipids synthesis improves osmotic tolerance of Saccharomyces cerevisiae.


State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China [Email]


To enhance the growth performance of Saccharomyces cerevisiae under osmotic stress, mutant XCG001, which tolerates up to 1.5 M NaCl, was isolated through adaptive laboratory evolution (ALE). Comparisons of the transcriptome data of mutant XCG001 and the wild-type strain identified ELO2 as being associated with osmotic tolerance. In the ELO2 overexpression strain (XCG010), the contents of inositol phosphorylceramide (IPC, t18:0/26:0), mannosylinositol phosphorylceramide (MIPC, t18:0/22:0(2OH)), MIPC (d18:0/22:0), MIPC (d20:0/24:0), mannosyldiinositol phosphorylceramide (M(IP)2C, d20:0/26:0), M(IP)2C (t18:0/26:0(2OH)), and M(IP)2C (d20:0/26:0(2OH)) increased by 88.3 times, 167 times, 63.3 times, 23.9 times, 27.9 times, 114 times, and 208 times at 1.0 M NaCl, respectively, compared with the corresponding values of the control strain XCG002. As a result, the membrane integrity, cell growth, and cell survival rate of strain XCG010 increased by 24.4% ± 1.0%, 21.9% ± 1.5%, and 22.1% ± 1.1% at 1.0 M NaCl, respectively, compared with the corresponding values of the control strain XCG002 (wild-type strain with a control plasmid). These findings provided a novel strategy for engineering complex sphingolipids to enhance osmotic tolerance.IMPORTANCEThis study demonstrated a novel strategy for manipulation membrane complex sphingolipids to enhance S. cerevisiae tolerance to osmotic stress. Elo2, a sphingolipid acyl chain elongase, was related to osmotic tolerance, through transcriptome analysis of the wild-type strain and an osmotic tolerant strain generated from ALE. Overexpression of ELO2 increased the content of complex sphingolipid with longer acyl chain, thus membrane integrity and osmotic tolerance improved.

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