The nodule inception-like protein 7 modulates nitrate sensing and metabolism in Arabidopsis

Authors

  • Loren Castaings,

    1. Institut Jean-Pierre Bourgin, Unité de Nutrition Azotée des Plantes, INRA, Route de St Cyr, F-78026 Versailles Cedex, France
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  • Antonio Camargo,

    1. Departamento de Bioquimica y Biologia Molecular, Facultad de Ciencas, Universidad de Cordoba, Campus de Rabanales, E-14071 Cordoba, Spain
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  • Delphine Pocholle,

    1. Institut Jean-Pierre Bourgin, Unité de Nutrition Azotée des Plantes, INRA, Route de St Cyr, F-78026 Versailles Cedex, France
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  • Virginie Gaudon,

    1. Institut Jean-Pierre Bourgin, Unité de Nutrition Azotée des Plantes, INRA, Route de St Cyr, F-78026 Versailles Cedex, France
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  • Yves Texier,

    1. Institut Jean-Pierre Bourgin, Unité de Nutrition Azotée des Plantes, INRA, Route de St Cyr, F-78026 Versailles Cedex, France
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  • Stéphanie Boutet-Mercey,

    1. Institut Jean-Pierre Bourgin, Unité de Nutrition Azotée des Plantes, INRA, Route de St Cyr, F-78026 Versailles Cedex, France
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  • Ludivine Taconnat,

    1. Unité de Recherche en Génomique Végétale, INRA, 2 rue Gaston Crémieux, CP5708, 91057 Evry Cedex, France
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  • Jean-Pierre Renou,

    1. Unité de Recherche en Génomique Végétale, INRA, 2 rue Gaston Crémieux, CP5708, 91057 Evry Cedex, France
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  • Françoise Daniel-Vedele,

    1. Institut Jean-Pierre Bourgin, Unité de Nutrition Azotée des Plantes, INRA, Route de St Cyr, F-78026 Versailles Cedex, France
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  • Emilio Fernandez,

    1. Departamento de Bioquimica y Biologia Molecular, Facultad de Ciencas, Universidad de Cordoba, Campus de Rabanales, E-14071 Cordoba, Spain
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  • Christian Meyer,

    1. Institut Jean-Pierre Bourgin, Unité de Nutrition Azotée des Plantes, INRA, Route de St Cyr, F-78026 Versailles Cedex, France
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  • Anne Krapp

    Corresponding author
    1. Institut Jean-Pierre Bourgin, Unité de Nutrition Azotée des Plantes, INRA, Route de St Cyr, F-78026 Versailles Cedex, France
      (fax +33 1 30 83 30 96; e-mail anne.krapp@versailles.inra.fr).
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(fax +33 1 30 83 30 96; e-mail anne.krapp@versailles.inra.fr).

Summary

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.

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