Evolution and regulation of nitrogen flux through compartmentalized metabolic networks in a marine diatom
Evolution and regulation of nitrogen flux through compartmentalized metabolic networks in a marine diatom
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DOI：
10.1038/s41467-019-12407-y
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发表时间：
2019-10-07
影响因子：
16.6
通讯作者：
Allen, Andrew E.
中科院分区：
文献类型：
--
作者：
Smith, Sarah R.;Dupont, Chris L.;Allen, Andrew E.
硅藻在硝酸盐的竞争中胜过其他浮游植物，但人们对这种能力的机制知之甚少。基因组和基因组支持的研究表明，硅藻具有氮代谢的独特特征，但对营养利用和生长的影响却知之甚少。利用转录组学、蛋白质组学、代谢组学、通量组学和通量平衡分析相结合的方法，研究三角褐指藻模式羽状硅藻氮素利用的短期变化，从系统水平上了解氮素的同化作用和胞内分布。在硅藻中，叶绿体和线粒体在碳和氮代谢的关键交叉点上被能量整合。参与这种整合的途径包括细胞器定位的GS-GOGAT循环，用于氨基部分交换的天冬氨酸和丙氨酸系统，以及阐明硅藻尿素循环作用的分裂细胞器精氨酸生物合成途径。这种独特的结构使硅藻能够有效地适应不断变化的氮素状况，从而赋予了相对于其他浮游植物类群的生态优势。
Diatoms outcompete other phytoplankton for nitrate, yet little is known about the mechanisms underpinning this ability. Genomes and genome-enabled studies have shown that diatoms possess unique features of nitrogen metabolism however, the implications for nutrient utilization and growth are poorly understood. Using a combination of transcriptomics, proteomics, metabolomics, fluxomics, and flux balance analysis to examine short-term shifts in nitrogen utilization in the model pennate diatom in Phaeodactylum tricornutum, we obtained a systems-level understanding of assimilation and intracellular distribution of nitrogen. Chloroplasts and mitochondria are energetically integrated at the critical intersection of carbon and nitrogen metabolism in diatoms. Pathways involved in this integration are organelle-localized GS-GOGAT cycles, aspartate and alanine systems for amino moiety exchange, and a split-organelle arginine biosynthesis pathway that clarifies the role of the diatom urea cycle. This unique configuration allows diatoms to efficiently adjust to changing nitrogen status, conferring an ecological advantage over other phytoplankton taxa.