Type-A response regulators are required for proper root apical meristem function through post-transcriptional regulation of PIN auxin efflux carriers
Article first published online: 21 JUL 2011
© 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd
The Plant Journal
Volume 68, Issue 1, pages 1–10, October 2011
How to Cite
Zhang, W., To, J. P. C., Cheng, C.-Y., Eric Schaller, G. and Kieber, J. J. (2011), Type-A response regulators are required for proper root apical meristem function through post-transcriptional regulation of PIN auxin efflux carriers. The Plant Journal, 68: 1–10. doi: 10.1111/j.1365-313X.2011.04668.x
- Issue published online: 29 SEP 2011
- Article first published online: 21 JUL 2011
- Accepted manuscript online: 6 JUN 2011 09:23AM EST
- Received 5 April 2011; revised 31 May 2011; accepted 2 June 2011; published online 21 July 2011.
- two-component signaling;
- root development
The phytohormones cytokinin and auxin regulate a diverse array of plant processes, often acting together to modulate growth and development. Although much has been learned with regard to how each of these hormones act individually, we are just beginning to understand how these signals interact to achieve an integrated response. Previous studies indicated that exogenous cytokinin has an effect on the transcription of several PIN efflux carriers. Here we show that disruption of type-A Arabidopsis response regulators (ARRs), which are negative regulators of cytokinin signalling, alters the levels of PIN proteins and results in increased sensitivity to N-1-naphthylphthalamic acid, an inhibitor of polar auxin transport. Disruption of eight of the 10 type-A ARR genes affects root development by altering the size of the apical meristem. Furthermore, we show that the effect of cytokinin on PIN abundance occurs primarily at the post-transcriptional level. Alterations of PIN levels in the type-A ARR mutants result in changes in the distribution of auxin in root tips as measured by a DR5::GFP reporter, and an altered pattern of cell division and differentiation in the stem cell niche in the root apical meristem. Together, these data indicate that cytokinin, acting through the type-A ARRs, alters the level of several PIN efflux carriers, and thus regulates the distribution of auxin within the root tip.