Whole-cell response to nitrogen deprivation in the diatom Phaeodactylum tricornutum.
Whole-cell response to nitrogen deprivation in the diatom Phaeodactylum tricornutum.
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DOI：
10.1093/jxb/erv340
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发表时间：
2015-10
影响因子：
6.9
通讯作者：
Brembu T
中科院分区：
文献类型：
--
作者：
Alipanah L;Rohloff J;Winge P;Bones AM;Brembu T
综合转录组学和代谢组学分析的硅藻Phaeodactylum tricornutum的氮剥夺反应揭示了内部含氮资源的再动员，以及碳和脂质结构的重塑。藻类生长受氮（N）有效性的强烈影响。硅藻是一类重要的生态单细胞藻类，科普氮素缺乏的条件下，已经进化出多种适应机制。在这项研究中，我们整合了生理数据与转录和代谢数据，以揭示在氮剥夺条件下的海洋硅藻三角褐指藻的分子和代谢修饰。生理和代谢产物的测量表明，光合能力和叶绿素含量的细胞减少，而中性脂质增加在N剥夺文化。全局基因表达分析表明，三角褐指藻通过增加氮运输、同化和利用有机氮资源来响应氮剥夺。氮剥夺后，减少生物合成和N化合物，如氨基酸，蛋白质和核酸的再循环增加，观察在转录水平。大多数与光合作用和叶绿素生物合成相关的基因也被抑制。通过下调卡尔文循环和金藻毒素生物合成，协调上调糖酵解、三羧酸循环和丙酮酸代谢，重组碳代谢，导致碳源向脂质代谢汇集。最后，膜脂的重新分配和三酰甘油从头生物合成的诱导引导细胞积累中性脂质。
An integrated transcriptomics and metabolomics analysis of the nitrogen-deprivation response in the diatom Phaeodactylum tricornutum uncovered remobilization of internal nitrogen-containing resources, and remodelling of carbon and lipid structures. Algal growth is strongly affected by nitrogen (N) availability. Diatoms, an ecologically important group of unicellular algae, have evolved several acclimation mechanisms to cope with N deprivation. In this study, we integrated physiological data with transcriptional and metabolite data to reveal molecular and metabolic modifications in N-deprived conditions in the marine diatom Phaeodactylum tricornutum. Physiological and metabolite measurements indicated that the photosynthetic capacity and chlorophyll content of the cells decreased, while neutral lipids increased in N-deprived cultures. Global gene expression analysis showed that P. tricornutum responded to N deprivation through an increase in N transport, assimilation, and utilization of organic N resources. Following N deprivation, reduced biosynthesis and increased recycling of N compounds like amino acids, proteins, and nucleic acids was observed at the transcript level. The majority of the genes associated with photosynthesis and chlorophyll biosynthesis were also repressed. Carbon metabolism was restructured through downregulation of the Calvin cycle and chrysolaminarin biosynthesis, and co-ordinated upregulation of glycolysis, the tricarboxylic acid cycle, and pyruvate metabolism, leading to funnelling of carbon sources to lipid metabolism. Finally, reallocation of membrane lipids and induction of de novo triacylglycerol biosynthesis directed cells to accumulation of neutral lipids.