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Citation
Tags
HERO ID
516761
Reference Type
Journal Article
Title
Cytokinin regulates root meristem activity via modulation of the polar auxin transport
Author(s)
Ruzicka, K; Simaskova, M; Duclercq, J; Petrasek, J; Zazimalova, E; Simon, S; Friml, J; Van Montagu, MCE; Benkova, E
Year
2009
Is Peer Reviewed?
1
Journal
Proceedings of the National Academy of Sciences of the United States of America
ISSN:
0027-8424
EISSN:
1091-6490
Volume
106
Issue
11
Page Numbers
4284-4289
Language
English
DOI
10.1073/pnas.0900060106
Web of Science Id
WOS:000264278800043
Abstract
Plant development is governed by signaling molecules called phytohormones. Typically, in certain developmental processes more than 1 hormone is implicated and, thus, coordination of their overlapping activities is crucial for correct plant development. However, molecular mechanisms underlying the hormonal crosstalk are only poorly understood. Multiple hormones including cytokinin and auxin have been implicated in the regulation of root development. Here we dissect the roles of cytokinin in modulating growth of the primary root. We show that cytokinin effect on root elongation occurs through ethylene signaling whereas cytokinin effect on the root meristem size involves ethylene-independent modulation of transport-dependent asymmetric auxin distribution. Exogenous or endogenous modification of cytokinin levels and cytokinin signaling lead to specific changes in transcription of several auxin efflux carrier genes from the PIN family having a direct impact on auxin efflux from cultured cells and on auxin distribution in the root apex. We propose a novel model for cytokinin action in regulating root growth: Cytokinin influences cell-to-cell auxin transport by modification of expression of several auxin transport components and thus modulates auxin distribution important for regulation of activity and size of the root meristem.
Keywords
auxin; auxin transport; cytokinin; hormonal crosstalk; root meristem; cultured tobacco cells; arabidopsis-thaliana; ethylene biosynthesis; expression; plants; efflux; growth; gene; pin; gradients
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