比较基因组分析Yarrowia lipolytica BBE-17的赤藓糖醇合成机制

Comparative genomic analysis of erythritol synthesis mechanism in Yarrowia lipolytica BBE-17

Yarrowia lipolytica BBE-17是一种野生型非模式菌,可发酵生产赤藓糖醇,具有潜在的工业应用价值。我们将菌株BBE-17与模式菌株CLIB122进行了比较基因组分析,探究其赤藓糖醇积累的可能机制,揭示了BBE-17中43921个单核苷酸多态性(SNPs),8078个小片段插入和缺失。此外,与参考基因组相比,发现了129个基因组结构变异和142个覆盖六条染色体的DNA拷贝数变异。在这些变异中,与赤藓糖醇合成有关的途径基因只有TKL1和ER,分别发生了1个单核苷酸多态性变化,并且只导致1个氨基酸发生改变,表明这两个基因中的SNP不是造成赤藓糖醇积累的主要原因,而BBE-17中大量的缺失型基因组变化可能是代谢网络改变的主要原因,也可能是靶向代谢途径增强和赤藓糖醇积累的主要原因。在基因组层面全局揭示了BBE-17与CLIB122的差异,探寻其积累赤藓糖醇的机制,为进一步优化改造亚罗解脂酵母生产赤藓糖醇提供了思路和理论依据。

Yarrowia lipolytica BBE-17 is a wild-type non-model strain, with potential industrial application value due to its ability of accumulating erythritol by fermentation. In this study, we carried out comparative genomic analysis and compared Yarrowia lipolytica BBE-17 with the model strain Yarrowia lipolytica CLIB122, to identify the potential mechanisms of erythritol accumulation. Comparative genomic analysis revealed 43921 single nucleotide polymorphisms(SNPs), 8078 small fragment insertions and deletion in Yarrowia lipolytica BBE-17. In addition, compared with the reference genome, 129 genomic structural variations and 142 DNA copy number variations involving six chromosomes were found. Notably, majority of the variations were of the deletion type. Interestingly, only two key pathway genes, TKL1 and ER, were related to erythritol synthesis, contained SNPs, and only one of these led to an amino acid change in the protein, suggesting that the SNPs in these two genes may not be the main reason for erythritol accumulation. Compared with the model strain, the vast number of genomic changes of the deletion type in Yarrowia lipolytica BBE-17 may be responsible for alteration of the overall metabolic network and is the main reason for the enhancement of target metabolic pathway and accumulation of erythritol. Our data provides idea and theoretical basis for further optimization of production of erythritol by Yarrowia lipolytica strains.