The nodule inception-like protein 7 modulates nitrate sensing and metabolism in Arabidopsis
The nodule inception-like protein 7 modulates nitrate sensing and metabolism in Arabidopsis
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DOI：
10.1111/j.1365-313x.2008.03695.x
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发表时间：
2009-02-01
期刊：
影响因子：
7.2
通讯作者：
Krapp, Anne
中科院分区：
文献类型：
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作者：
Castaings, Loren;Camargo, Antonio;Krapp, Anne
硝酸盐是一种必需的营养物质，参与植物的许多适应性反应，如根的局部增殖、开花或气孔运动。这种硝酸盐特异性机制是如何在分子水平上调控的，人们知之甚少。虽然拟南芥ANR1转录因子似乎控制了硝酸盐对侧根伸长的刺激，但迄今为止还没有在高等植物中发现硝酸盐同化的调节因子。豆科植物特有的共生固氮是由一种被认为是转录因子NIN控制的。最近，藻类同源物NIT2被发现调节硝酸盐同化。在这里，我们报道了拟南芥nin样蛋白7 （NLP7）敲除突变体组成性地表现出氮饥饿植物的几个特征，并且它们耐受干旱胁迫。我们发现nlp7突变体在硝酸盐信号转导中受损，并且nlp7的表达模式与nlp7在氮感知中的功能一致。与GFP的翻译融合显示NLP7推定转录因子的核定位。我们认为NLP7是硝酸盐信号转导途径的重要组成部分，是非结瘤植物氮同化的新调控蛋白。
Nitrate is an essential nutrient, and is involved in many adaptive responses of plants, such as localized proliferation of roots, flowering or stomatal movements. How such nitrate-specific mechanisms are regulated at the molecular level is poorly understood. Although the Arabidopsis ANR1 transcription factor appears to control stimulation of lateral root elongation in response to nitrate, no regulators of nitrate assimilation have so far been identified in higher plants. Legume-specific symbiotic nitrogen fixation is under the control of the putative transcription factor, NIN, in Lotus japonicus. Recently, the algal homologue NIT2 was found to regulate nitrate assimilation. Here we report that Arabidopsis thaliana NIN-like protein 7 (NLP7) knockout mutants constitutively show several features of nitrogen-starved plants, and that they are tolerant to drought stress. We show that nlp7 mutants are impaired in transduction of the nitrate signal, and that the NLP7 expression pattern is consistent with a function of NLP7 in the sensing of nitrogen. Translational fusions with GFP showed a nuclear localization for the NLP7 putative transcription factor. We propose NLP7 as an important element of the nitrate signal transduction pathway and as a new regulatory protein specific for nitrogen assimilation in non-nodulating plants.