Journal article

Shoot-supplied ammonium targets the root auxin influx carrier AUX1 and inhibits lateral root emergence in Arabidopsis

B Li, Q Li, Y Su, H Chen, L Xiong, G Mi, HJ Kronzucker, W Shi

Plant Cell and Environment | WILEY-BLACKWELL | Published : 2011

Abstract

Deposition of ammonium (NH4+) from the atmosphere is a substantial environmental problem. While toxicity resulting from root exposure to NH4+ is well studied, little is known about how shoot-supplied ammonium (SSA) affects root growth. In this study, we show that SSA significantly affects lateral root (LR) development. We show that SSA inhibits lateral root primordium (LRP) emergence, but not LRP initiation, resulting in significantly impaired LR number. We show that the inhibition is independent of abscisic acid (ABA) signalling and sucrose uptake in shoots but relates to the auxin response in roots. Expression analyses of an auxin-responsive reporter, DR5:GUS, and direct assays of auxin tr..

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University of Melbourne Researchers

Grants

Awarded by National Basic Research Program of China


Awarded by National Natural Science Foundation of China


Awarded by National Sciences and Engineering Research Council of Canada (NSERC)


Funding Acknowledgements

We thank Professors Malcolm Bennett (University of Nottingham), Ben Scheres (Utrecht University) and Tom Guilfoyle (University of Missouri) for providing the transgenic lines of Arabidopsis, and the Arabidopsis Biological Resource Center for the mutant seeds. We are grateful to Malcolm Bennett (University of Nottingham) for invaluable advice during designing and writing of the manuscript. We also thank other members of our team for helpful comments on the manuscript. This work was supported by the National Basic Research Program of China (2007CB109303), the National Natural Science Foundation of China (30771285) and the National Sciences and Engineering Research Council of Canada (NSERC, Discovery Grant 217277-2009).