Cell, Molecular Biology and Genomics Group, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway.
PLoS One. 2018 Feb 23;13(2):e0193335. doi: 10.1371/journal.pone.0193335. eCollection 2018.
Phosphorus, an essential element for all living organisms, is a limiting nutrient in many regions of the ocean due to its fast recycling. Changes in phosphate (Pi) availability in aquatic systems affect diatom growth and productivity. We investigated the early adaptive mechanisms in the marine diatom Phaeodactylum tricornutum to P deprivation using a combination of transcriptomics, metabolomics, physiological and biochemical experiments. Our analysis revealed strong induction of gene expression for proteins involved in phosphate acquisition and scavenging, and down-regulation of processes such as photosynthesis, nitrogen assimilation and nucleic acid and ribosome biosynthesis. P deprivation resulted in alterations of carbon allocation through the induction of the pentose phosphate pathway and cytosolic gluconeogenesis, along with repression of the Calvin cycle. Reorganization of cellular lipids was indicated by coordinated induced expression of phospholipases, sulfolipid biosynthesis enzymes and a putative betaine lipid biosynthesis enzyme. A comparative analysis of nitrogen- and phosphorus-deprived P. tricornutum revealed both common and distinct regulation patterns in response to phosphate and nitrate stress. Regulation of central carbon metabolism and amino acid metabolism was similar, whereas unique responses were found in nitrogen assimilation and phosphorus scavenging in nitrogen-deprived and phosphorus-deprived cells, respectively.
磷是所有生物的必需元素，但由于其快速循环，在海洋的许多区域中都是一种限制营养物质。水系统中磷酸盐（Pi）供应的变化会影响硅藻的生长和生产力。我们使用转录组学、代谢组学、生理和生化实验相结合的方法，研究了海洋硅藻三角褐指藻对磷缺乏的早期适应机制。我们的分析表明，与光合作用、氮同化以及核酸和核糖体生物合成等过程的下调相比，磷获取和清除相关蛋白的基因表达被强烈诱导。磷缺乏通过诱导磷酸戊糖途径和细胞质糖异生，同时抑制卡尔文循环，导致碳分配的改变。通过磷脂酶、硫酸脂生物合成酶和一种假定的甜菜碱脂生物合成酶的协调诱导表达，表明细胞脂质的重新组合。对氮磷缺乏三角褐指藻的比较分析表明，对磷酸盐和硝酸盐胁迫的响应存在共同和独特的调节模式。在氮同化和磷清除方面，氮缺乏和磷缺乏细胞分别表现出独特的响应，而在中心碳代谢和氨基酸代谢方面的调节则相似。
