ABSTRACT: Phosphorus (P) limits primary production in regions of the surface ocean, and many plankton species exhibit specific physiological responses to P deficiency. The metabolic response of Micromonas pusilla, an ecologically relevant marine photoautotroph, to P deficiency was investigated using metabolomics and comparative genomics. The concentrations of some intracellular metabolites were elevated in the P-deficient cells (e.g. xanthine, inosine), and genes involved in the associated metabolic pathways shared a predicted conserved amino acid motif in the non-coding regions of each gene. The presence of the conserved motif suggests that these genes may be co-regulated, and the motif may constitute a regulatory element for binding a transcription factor, specifically that of Psr1 (phosphate starvation response). A putative phosphate starvation response gene ( psr1-like) was identified in M. pusilla with homology to well characterized psr1/ phr1 genes in algae and plants, respectively. This gene appears to be present and expressed in other marine algal taxa (e.g. Emiliania huxleyi) in field sites that are chronically P limited. Results from the present study have implications for understanding phytoplankton taxon-specific roles in mediating P cycling in the ocean.

中文翻译：

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存在磷饥饿反应基因（类psr1）并在小单胞菌和其他海藻中表达

摘要：磷（P）限制了海洋表层区域的初级生产，许多浮游生物对磷缺乏表现出特定的生理反应。毛小单胞菌的代谢反应利用代谢组学和比较基因组学研究了与磷缺乏症有关的生态相关海洋光合自养生物。P缺陷型细胞（例如黄嘌呤，肌苷）中某些细胞内代谢物的浓度升高，并且参与相关代谢途径的基因在每个基因的非编码区共有一个预测的保守氨基酸基序。保守基序的存在表明这些基因可以被共同调控，并且该基序可以构成用于结合转录因子，特别是Psr1（磷酸饥饿反应）的转录因子的调控元件。推定的磷酸盐饥饿响应基因（PSR 1样）中被确定M. pusilla同源良好表征的PSR 1 / PHR藻类和植物中分别有1个基因。该基因似乎存在于其他长期受磷限制的田间地点的海洋藻类群中（例如Emiliania huxleyi）并表达。本研究的结果对于理解浮游植物分类群在介导海洋磷循环中的作用具有重要意义。