Nitrate commands genome-wide gene expression changes that impact metabolism, physiology, plant growth, and development. In an effort to identify new components involved in nitrate responses in plants, we analyze the Arabidopsis thaliana root phosphoproteome in response to nitrate treatments via liquid chromatography coupled to tandem mass spectrometry. 176 phosphoproteins show significant changes at 5 or 20 min after nitrate treatments. Proteins identified by 5 min include signaling components such as kinases or transcription factors. In contrast, by 20 min, proteins identified were associated with transporter activity or hormone metabolism functions, among others. The phosphorylation profile of NITRATE TRANSPORTER 1.1 (NRT1.1) mutant plants was significantly altered as compared to wild-type plants, confirming its key role in nitrate signaling pathways that involves phosphorylation changes. Integrative bioinformatics analysis highlights auxin transport as an important mechanism modulated by nitrate signaling at the post-translational level. We validated a new phosphorylation site in PIN2 and provide evidence that it functions in primary and lateral root growth responses to nitrate.

中文翻译：

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硝酸盐引发的磷酸化蛋白质组变化和 PIN2 磷酸位点调节根系结构

硝酸盐命令影响新陈代谢、生理、植物生长和发育的全基因组基因表达变化。为了确定植物中与硝酸盐反应有关的新成分，我们通过液相色谱与串联质谱联用分析了拟南芥根磷酸化蛋白质组对硝酸盐处理的反应。176 种磷蛋白在硝酸盐处理后 5 或 20 分钟显示出显着变化。5 分钟后鉴定的蛋白质包括信号成分，如激酶或转录因子。相比之下，到 20 分钟时，鉴定出的蛋白质与转运蛋白活性或激素代谢功能等有关。NITRATE TRANSPORTER 1.1 ( NRT1.1)的磷酸化谱与野生型植物相比，突变植物发生了显着变化，证实了其在涉及磷酸化变化的硝酸盐信号通路中的关键作用。综合生物信息学分析强调生长素转运是翻译后水平上由硝酸盐信号调节的重要机制。我们验证了 PIN2 中的一个新磷酸化位点，并提供证据表明它在初级和侧根生长对硝酸盐的反应中起作用。