Membrane Glycerolipid Remodeling Triggered by Nitrogen and Phosphorus Starvation in Phaeodactylum tricornutum
Membrane Glycerolipid Remodeling Triggered by Nitrogen and Phosphorus Starvation in Phaeodactylum tricornutum
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DOI：
10.1104/pp.114.252395
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发表时间：
2015-01-01
期刊：
影响因子：
7.4
通讯作者：
Marechal, Eric
中科院分区：
文献类型：
--
作者：
Abida, Heni;Dolch, Lina-Juana;Marechal, Eric
硅藻是海水和淡水生态系统中浮游植物生物多样性的一个主要门类。已知它们通过三酰甘油的积累来响应环境的某些化学变化，但膜甘油脂中发生的相对变化尚未被研究。我们的目标是首先为海洋模式硅藻三角褐指藻的甘油脂体定义一个参考，这是描述和剖析脂代谢途径的必要前提，这些途径被协调和调节，以建立每个亚细胞膜隔室。通过结合多种分析技术，我们测定了在不同氮或磷供应水平下生长的三角帆船的甘油脂组分。在世界各地收集的不同三角侧耳种质中，任一种养分的缺乏都会引发三酰甘油的积累，但时间尺度和程度不同。我们深入研究了营养饥饿对Pt1菌株(藻类和原生动物培养集编号：1055/3)的影响。缺氮是更严重的胁迫，引发类囊体衰老和生长停滞。相比之下，缺磷诱导了一种阶梯式的适应性反应。甘油脂体变化的时间尺度以及与大规模转录组研究的比较表明，未知的初级磷储存分子(可能是多聚磷)的耗尽，以及某些编码特定脂肪合成酶的基因的转录控制。我们认为磷脂是在缺磷时分解的次级储磷分子，而非磷脂的合成是通过磷脂酰甘油到磺胺脂和磷脂酰胆碱到甜菜碱脂的置换以及三酰甘油的后期积累来实现的。
Diatoms constitute a major phylum of phytoplankton biodiversity in ocean water and freshwater ecosystems. They are known to respond to some chemical variations of the environment by the accumulation of triacylglycerol, but the relative changes occurring in membrane glycerolipids have not yet been studied. Our goal was first to define a reference for the glycerolipidome of the marine model diatom Phaeodactylum tricornutum, a necessary prerequisite to characterize and dissect the lipid metabolic routes that are orchestrated and regulated to build up each subcellular membrane compartment. By combining multiple analytical techniques, we determined the glycerolipid profile of P. tricornutum grown with various levels of nitrogen or phosphorus supplies. In different P. tricornutum accessions collected worldwide, a deprivation of either nutrient triggered an accumulation of triacylglycerol, but with different time scales and magnitudes. We investigated in depth the effect of nutrient starvation on the Pt1 strain (Culture Collection of Algae and Protozoa no. 1055/3). Nitrogen deprivation was the more severe stress, triggering thylakoid senescence and growth arrest. By contrast, phosphorus deprivation induced a stepwise adaptive response. The time scale of the glycerolipidome changes and the comparison with large-scale transcriptome studies were consistent with an exhaustion of unknown primary phosphorus-storage molecules (possibly polyphosphate) and a transcriptional control of some genes coding for specific lipid synthesis enzymes. We propose that phospholipids are secondary phosphorus-storage molecules broken down upon phosphorus deprivation, while nonphosphorus lipids are synthesized consistently with a phosphatidylglycerol-to-sulfolipid and a phosphatidycholine-to-betaine lipid replacement followed by a late accumulation of triacylglycerol.