Browsing by Author "Lejay, Laurence"

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    Genome-wide analysis in response to nitrogen and carbon identifies regulators for root AtNRT2 transporters
    (2021) Ruffel, Sandrine; Chaput, Valentín; Przybyla Toscano, Jonathan; Fayos, Ian; Ibarra, Catalina; Moyano, Tomás; Fizames, Cécile; Tillard, Pascal; O’Brien, José Antonio; Gutiérrez, Rodrigo A.; Gojon, Alain; Lejay, Laurence
    In Arabidopsis (Arabidopsis thaliana), the High-Affinity Transport System (HATS) for root nitrate (⁠NO3−⁠) uptake depends mainly on four NRT2 NO3− transporters, namely NRT2.1, NRT2.2, NRT2.4, and NRT2.5. The HATS is the target of many regulations to coordinate nitrogen (N) acquisition with the N status of the plant and with carbon (C) assimilation through photosynthesis. At the molecular level, C and N signaling pathways control gene expression of the NRT2 transporters. Although several regulators of these transporters have been identified in response to either N or C signals, the response of NRT2 gene expression to the interaction of these signals has never been specifically investigated, and the underlying molecular mechanisms remain largely unknown. To address this question we used an original systems biology approach to model a regulatory gene network targeting NRT2.1, NRT2.2, NRT2.4, and NRT2.5 in response to N/C signals. Our systems analysis of the data identified three transcription factors, TGA3, MYC1, and bHLH093. Functional analysis of mutants combined with yeast one-hybrid experiments confirmed that all three transcription factors are regulators of NRT2.4 or NRT2.5 in response to N or C signals. These results reveal a role for TGA3, MYC1, and bHLH093 in controlling the expression of root NRT2 transporter genes.
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    Nitrate in 2020: Thirty years from transport to signaling networks
    (2020) Vidal, Elena A.; Alvarez, José M.; Araus, Viviana; Riveras Hernández, Eleodoro Javier; Brooks, Matthew D.; Krouk, Gabriel; Ruffel, Sandrine; Lejay, Laurence; Crawford, Nigel M.; Coruzzi, Gloria M.; Gutiérrez Ilabaca, Rodrigo Antonio
    Nitrogen (N) is an essential macronutrient for plants and a major limiting factor for plant growth and crop production. Nitrate is the main source of N available to plants in agricultural soils and in many natural environments. Sustaining agricultural productivity is of paramount importance in the current scenario of increasing world population, diversification of crop uses, and climate change. Plant productivity for major crops around the world, however, is still supported by excess application of N-rich fertilizers with detrimental economic and environmental impacts. Thus, understanding how plants regulate nitrate uptake and metabolism is key for developing new crops with enhanced N use efficiency and to cope with future world food demands. The study of plant responses to nitrate has gained considerable interest over the last 30 years. This review provides an overview of key findings in nitrate research, spanning biochemistry, molecular genetics, genomics, and systems biology. We discuss how we have reached our current view of nitrate transport, local and systemic nitrate sensing/signaling, and the regulatory networks underlying nitrate-controlled outputs in plants. We hope this summary will serve not only as a timeline and information repository but also as a baseline to define outstanding questions for future research.