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Krouk G.,New York University | Krouk G.,CNRS Biochemistry and Plant Molecular Physiology Laboratory | Crawford N.M.,University of California at San Diego | Coruzzi G.M.,New York University | Tsay Y.-F.,Academia Sinica, Taiwan
Current Opinion in Plant Biology | Year: 2010

Nitrate (NO 3 -) is a key nutrient as well as a signaling molecule that impacts both metabolism and development of plants. Understanding the complexity of the regulatory networks that control nitrate uptake, metabolism, and associated responses has the potential to provide solutions that address the major issues of nitrate pollution and toxicity that threaten agricultural and ecological sustainability and human health. Recently, major advances have been made in cataloguing the nitrate transcriptome and in identifying key components that mediate nitrate signaling. In this perspective, we describe the genes involved in nitrate regulation and how they influence nitrate transport and assimilation, and we discuss the role of systems biology approaches in elucidating the gene networks involved in NO 3 - signaling adaptation to fluctuating environments. © 2010.


Medici A.,CNRS Biochemistry and Plant Molecular Physiology Laboratory | Krouk G.,CNRS Biochemistry and Plant Molecular Physiology Laboratory
Journal of Experimental Botany | Year: 2014

Nitrate (NO3-) application strongly affects gene expression in plants. This regulation is thought to be crucial for their adaptation in response to a changing nutritional environment. Depending on the conditions preceding or concomitant with nitrate provision, the treatment can affect up to a 10th of genome expression in Arabidopsis thaliana. The early events occurring after NO3- provision are often called the Primary Nitrate Response (PNR). Despite this simple definition, PNR is a complex process that is difficult to properly delineate. Here we report the different concepts related to PNR, review the different molecular components known to control it, and show, using meta-analysis, that this concept/pathway is not monolithic. We especially bring our attention to the genome-wide effects of LBD37 and LBD38 overexpression, NLP7, and CHL1/NRT1.1 mutations. © The Author 2014.


Ruffel S.,CNRS Biochemistry and Plant Molecular Physiology Laboratory | Gojon A.,CNRS Biochemistry and Plant Molecular Physiology Laboratory | Lejay L.,CNRS Biochemistry and Plant Molecular Physiology Laboratory
Journal of Experimental Botany | Year: 2014

In most aerobic soils, nitrate (NO3-) is the main nitrogen source for plants and is often limiting for plant growth and development. To adapt to a changing environment, plants have developed complex regulatory mechanisms that involve short and long-range signalling pathways in response to both NO3- availability in the soil and other physiological processes like growth or nitrogen (N) and carbon (C) metabolisms. Over the past decade, transcriptomic approaches largely contributed to the identification of molecular elements involved in these regulatory mechanisms, especially at the level of root NO3- uptake. Most strikingly, the data obtained revealed the high level of interaction between N and both hormone and C signalling pathways, suggesting a strong dependence on growth, development, and C metabolism to adapt root NO3- uptake to both external NO3- availability and the N status of the plant. However, the signalling mechanisms involved in the cross-talk between N, C, and hormones for the regulation of root NO3- uptake remain largely obscure. The aim of this review is to discuss the recent advances concerning the regulatory pathways controlling NO3- uptake in response to N signalling, hormones, and C in the model plant Arabidopsis thaliana. Then, to further characterize the level of interaction between these signalling pathways we built on publicly available transcriptome data to determine how hormones and C treatments modify the gene network connecting root NO3- transporters and their regulators. © The Author 2014.


Bouguyon E.,CNRS Biochemistry and Plant Molecular Physiology Laboratory | Gojon A.,CNRS Biochemistry and Plant Molecular Physiology Laboratory | Nacry P.,CNRS Biochemistry and Plant Molecular Physiology Laboratory
Seminars in Cell and Developmental Biology | Year: 2012

Nitrate (NO 3 -) is a major nutrient for plants, taken up by their roots from the soil. Plants are able to sense NO 3 - in their environment, allowing them to quickly respond to the dramatic fluctuations of its availability. Significant advances have been made during the recent period concerning the molecular mechanisms of NO 3 - sensing and signaling in the model plant Arabidopsis thaliana. The striking action of NO 3 - as a signal regulating genome expression has been unraveled. Note worthily, NO 3 - sensing systems have been identified. These correspond to membrane transporters also ensuring the uptake of NO 3 - into root cells, thus generalizing the nutrient 'transceptor' (transporter/receptor) concept defined in yeast. Furthermore, components of the downstream transduction cascades, such as transcription factors or kinases, have also been isolated. A breakthrough arising from this improved knowledge is a better understanding of the integration of NO 3 - and hormone signaling pathways, that explains the extraordinary developmental plasticity of plants in response to NO 3 -. © 2012 Elsevier Ltd.


Nacry P.,CNRS Biochemistry and Plant Molecular Physiology Laboratory | Bouguyon E.,CNRS Biochemistry and Plant Molecular Physiology Laboratory | Gojon A.,CNRS Biochemistry and Plant Molecular Physiology Laboratory
Plant and Soil | Year: 2013

Background: Nitrogen (N) is one of the key mineral nutrients for plants and its availability has a major impact on their growth and development. Most often N resources are limiting and plants have evolved various strategies to modulate their root uptake capacity to compensate for both spatial and temporal changes in N availability in soil. The main N sources for terrestrial plants in soils of temperate regions are in decreasing order of abundance, nitrate, ammonium and amino acids. N uptake systems combine, for these different N forms, high- and low-affinity transporters belonging to multige families. Expression and activity of most uptake systems are regulated locally by the concentration of their substrate, and by a systemic feedback control exerted by whole-plant signals of N status, giving rise to a complex combinatory network. Besides modulation of the capacity of transport systems, plants are also able to modulate their growth and development to maintain N homeostasis. In particular, root system architecture is highly plastic and its changes can greatly impact N acquisition from soil. Scope: In this review, we aim at detailing recent advances in the identification of molecular mechanisms responsible for physiological and developmental responses of root N acquisition to changes in N availability. These mechanisms are now unravelled at an increasing rate, especially in the model plant Arabidopsis thaliana L. Within the past decade, most root membrane transport proteins that determine N acquisition have been identified. More recently, molecular regulators in nitrate or ammonium sensing and signalling have been isolated, revealing common regulatory genes for transport system and root development, as well as a strong connection between N and hormone signalling pathways. Conclusion: Deciphering the complexity of the regulatory networks that control N uptake, metabolism and plant development will help understanding adaptation of plants to sub-optimal N availability and fluctuating environments. It will also provide solutions for addressing the major issues of pollution and economical costs related to N fertilizer use that threaten agricultural and ecological sustainability. © 2013 Springer Science+Business Media Dordrecht.


Boursiac Y.,CNRS Biochemistry and Plant Molecular Physiology Laboratory | Leran S.,CNRS Biochemistry and Plant Molecular Physiology Laboratory | Corratge-Faillie C.,CNRS Biochemistry and Plant Molecular Physiology Laboratory | Gojon A.,CNRS Biochemistry and Plant Molecular Physiology Laboratory | And 2 more authors.
Trends in Plant Science | Year: 2013

Abscisic acid (ABA) metabolism, perception, and transport form a triptych allowing higher plants to use ABA as a signaling molecule. The molecular bases of ABA metabolism are now well described and, over the past few years, several ABA receptors have been discovered. Although ABA transport has long been demonstrated in planta, the first breakthroughs in identifying plasma membrane-localized ABA transporters came in 2010, with the identification of two ATP-binding cassette (ABC) proteins. More recently, two ABA transporters in the nitrate transporter 1/peptide transporter (NRT1/PTR) family have been identified. In this review, we discuss the role of these different ABA transporters and examine the scientific impact of their identification. Given that the NRT1/PTR family is involved in the transport of nitrogen (N) compounds, further work should determine whether an interaction between ABA and N signaling or nutrition occurs. © 2013 Elsevier Ltd.


Prado K.,CNRS Biochemistry and Plant Molecular Physiology Laboratory | Maurel C.,CNRS Biochemistry and Plant Molecular Physiology Laboratory
Frontiers in Plant Science | Year: 2013

The water status of plant leaves is dependent on both stomatal regulation and water supply from the vasculature to inner tissues. The present review addresses the multiple physiological and mechanistic facets of the latter process. Inner leaf tissues contribute to at least a third of the whole resistance to water flow within the plant. Physiological studies indicated that leaf hydraulic conductance (Kleaf) is highly dependent on the anatomy, development and age of the leaf and can vary rapidly in response to physiological or environmental factors such as leaf hydration, light, temperature, or nutrient supply. Differences in venation pattern provide a basis for variations in Kleaf during development and between species. On a short time (hour) scale, the hydraulic resistance of the vessels can be influenced by transpiration-induced cavitations, wall collapses, and changes in xylem sap composition. The extravascular compartment includes all living tissues (xylem parenchyma, bundle sheath, and mesophyll) that transport water from xylem vessels to substomatal chambers. Pharmacological inhibition and reverse genetics studies have shown that this compartment involves water channel proteins called aquaporins (AQPs) that facilitate water transport across cell membranes. In many plant species, AQPs are present in all leaf tissues with a preferential expression in the vascular bundles. The various mechanisms that allow adjustment of Kleaf to specific environmental conditions include transcriptional regulation of AQPs and changes in their abundance, trafficking, and intrinsic activity. Finally, the hydraulics of inner leaf tissues can have a strong impact on the dynamic responses of leaf water potential and stomata, and as a consequence on plant carbon economy and leaf expansion growth. The manipulation of these functions could help optimize the entire plant performance and its adaptation to extreme conditions over short and long time scales. © 2013 Prado and Maurel.


Krouk G.,CNRS Biochemistry and Plant Molecular Physiology Laboratory
Plant Molecular Biology | Year: 2016

During their sessile mode of life, plants need to endure variations in their environment such as a drastic variability in the nutrient concentration in soil solution. It is almost trivial to say that such fluctuations in the soil modify plant growth, development and phase transitions. However, the signaling pathways underlying the connections between nitrogen related signaling and hormonal signaling controlling growth are still poorly documented. This review is meant to present how nitrate/nitrogen controls hormonal pathways. Furthermore, it is very interesting to highlight the increasing evidence that the hormonal signaling pathways themselves seem to feed back control of the nitrate/nitrogen transport and assimilation to adapt nutrition to growth. This thus defines a feed-forward cycle that finely coordinates plant growth and nutrition. © 2016 Springer Science+Business Media Dordrecht


Li G.,CNRS Biochemistry and Plant Molecular Physiology Laboratory | Santoni V.,CNRS Biochemistry and Plant Molecular Physiology Laboratory | Maurel C.,CNRS Biochemistry and Plant Molecular Physiology Laboratory
Biochimica et Biophysica Acta - General Subjects | Year: 2014

Background Aquaporins are membrane channels that facilitate the transport of water and small neutral molecules across biological membranes of most living organisms. Scope of review Here, we present comprehensive insights made on plant aquaporins in recent years, pointing to their molecular and physiological specificities with respect to animal or microbial counterparts. Major conclusions In plants, aquaporins occur as multiple isoforms reflecting a high diversity of cellular localizations and various physiological substrates in addition to water. Of particular relevance for plants is the transport by aquaporins of dissolved gases such as carbon dioxide or metalloids such as boric or silicic acid. The mechanisms that determine the gating and subcellular localization of plant aquaporins are extensively studied. They allow aquaporin regulation in response to multiple environmental and hormonal stimuli. Thus, aquaporins play key roles in hydraulic regulation and nutrient transport in roots and leaves. They contribute to several plant growth and developmental processes such as seed germination or emergence of lateral roots. General significance Plants with genetically altered aquaporin functions are now tested for their ability to improve plant resistance to stresses. This article is part of a Special Issue entitled Aquaporins. © 2013 Elsevier B.V.


Luu D.-T.,CNRS Biochemistry and Plant Molecular Physiology Laboratory | Luu D.-T.,Hanoi University | Maurel C.,CNRS Biochemistry and Plant Molecular Physiology Laboratory
Traffic | Year: 2013

Aquaporins (AQPs) are channel proteins that facilitate the transport of water and small solutes across biological membranes. In plants, AQPs exhibit a high multiplicity of isoforms in relation to a high diversity of sub-cellular localizations, at the plasma membrane (PM) and in various intracellular compartments. Some members also exhibit a dual localization in distinct cell compartments, whereas others show polarized or domain-specific expression at the PM or tonoplast, respectively. A diversity of mechanisms controlling the routing of newly synthesized AQPs towards their destination membranes and involving diacidic motifs, phosphorylation or tetramer assembly is being uncovered. Recent approaches using single particle tracking, fluorescence correlation spectroscopy and fluorescence recovery after photobleaching have, in combination with pharmacological interference, stressed the peculiarities of AQP sub-cellular dynamics in environmentally challenging conditions. A role for clathrin and sterol-rich domains in cell surface dynamics and endocytosis of PM AQPs was uncovered. These recent advances provide deep insights into the cellular mechanisms of water transport regulation in plants. They also point to AQPs as an emerging model for studying the sub-cellular dynamics of plant membrane proteins. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

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