Nitrate-regulated auxin transport by NRT1.1 defines a mechanism for nutrient sensing in plants Journal Article

Author(s): Krouk, Gabriel; Lacombe, Benoît; Bielach, Agnieszka; Perrine-Walker, Francine; Malínská, Kateřina; Mounier, Emmanuelle; Hoyerová, Klára; Tillard, Pascal; Leon, Sarah; Ljung, Karin; Zažímalová, Eva; Benková, Eva; Nacry, Philippe; Gojon, Alain
Article Title: Nitrate-regulated auxin transport by NRT1.1 defines a mechanism for nutrient sensing in plants
Abstract: Nitrate is both a nitrogen source for higher plants and a signal molecule regulating their development. In Arabidopsis, the NRT1.1 nitrate transporter is crucial for nitrate signaling governing root growth, and has been proposed to act as a nitrate sensor. However, the sensing mechanism is unknown. Herein we show that NRT1.1 not only transports nitrate but also facilitates uptake of the phytohormone auxin. Moreover, nitrate inhibits NRT1.1-dependent auxin uptake, suggesting that transduction of nitrate signal by NRT1.1 is associated with a modification of auxin transport. Among other effects, auxin stimulates lateral root development. Mutation of NRT1.1 enhances both auxin accumulation in lateral roots and growth of these roots at low, but not high, nitrate concentration. Thus, we propose that NRT1.1 represses lateral root growth at low nitrate availability by promoting basipetal auxin transport out of these roots. This defines a mechanism connecting nutrient and hormone signaling during organ development.
Keywords: Animals; Cells, Cultured; Female; Mutation; Food; Signal Transduction; plant roots; Xenopus; Oocytes; Gene Expression Regulation, Plant; Arabidopsis; Indoleacetic Acids; Biological Transport, Active; Chemoreceptor Cells; Nitrates; Periplasmic Binding Proteins; Tumor Suppressor Proteins
Journal Title: Developmental Cell
Volume: 18
Issue 6
ISSN: 1534-5807
Publisher: Cell Press  
Date Published: 2010-06-15
Start Page: 927
End Page: 937
DOI: 10.1016/j.devcel.2010.05.008
Open access: no