Elevated CO2 improves lipid accumulation by increasing carbon metabolism in Chlorella sorokiniana
Elevated CO2 improves lipid accumulation by increasing carbon metabolism in Chlorella sorokiniana
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DOI：
10.1111/pbi.12398
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发表时间：
2016-02-01
影响因子：
13.8
通讯作者：
Du, Jianchang
中科院分区：
文献类型：
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作者：
Sun, Zhilan;Chen, Yi-Feng;Du, Jianchang
向微藻提供额外的二氧化碳是一种很有希望的提高脂肪产量的方法。然而，二氧化碳升高条件下脂质堆积的分子机制仍未完全阐明。为了了解高二氧化碳如何改善脂质生产，我们对小球藻LS-2细胞在生长过程中的转录进行了测序，并比较了参与碳流的基因从二氧化碳到三酰甘油的转录动力学。这些分析确定了松材线虫LS-2中碳水化合物代谢和脂肪生物合成途径的大部分基因。在高剂量CO2胁迫下，尽管大多数从头合成脂肪酸的基因表达下调，但参与碳水化合物代谢途径的基因，包括碳固定、叶绿体糖酵解、丙酮酸脱氢酶复合体(PDHC)组分和叶绿体膜转运蛋白，在延长的脂肪积累阶段表达上调。这些数据表明，脂肪的产生在很大程度上独立于从头合成脂肪酸。二氧化碳浓度升高可能会促使细胞将光合作用的碳前体引入脂肪酸合成途径，导致三酰甘油的总生成量增加。为了支持这一观点，参与三酰甘油生物合成的基因大幅上调。因此，二氧化碳浓度升高可能会影响调控动态，导致碳流向三酰甘油的增加，从而为提高微藻的脂肪产量提供了一种可行的途径。
Supplying microalgae with extra CO2 is a promising means for improving lipid production. The molecular mechanisms involved in lipid accumulation under conditions of elevated CO2, however, remain to be fully elucidated. To understand how elevated CO2 improves lipid production, we performed sequencing of Chlorella sorokiniana LS-2 cellular transcripts during growth and compared transcriptional dynamics of genes involved in carbon flow from CO2 to triacylglycerol. These analyses identified the majority genes of carbohydrate metabolism and lipid biosynthesis pathways in C.sorokiniana LS-2. Under high doses of CO2, despite down-regulation of most de novo fatty acid biosynthesis genes, genes involved in carbohydrate metabolic pathways including carbon fixation, chloroplastic glycolysis, components of the pyruvate dehydrogenase complex (PDHC) and chloroplastic membrane transporters were upexpressed at the prolonged lipid accumulation phase. The data indicate that lipid production is largely independent of de novo fatty acid synthesis. Elevated CO2 might push cells to channel photosynthetic carbon precursors into fatty acid synthesis pathways, resulting in an increase of overall triacylglycerol generation. In support of this notion, genes involved in triacylglycerol biosynthesis were substantially up-regulated. Thus, elevated CO2 may influence regulatory dynamics and result in increased carbon flow to triacylglycerol, thereby providing a feasible approach to increase lipid production in microalgae.