Cytokinins influence root gravitropism via differential regulation of auxin transporter expression and localization in Arabidopsis
Language English Country England, Great Britain Media print-electronic
Document type Journal Article
PubMed
27322763
DOI
10.1111/nph.14049
Knihovny.cz E-resources
- Keywords
- AUX1, Arabidopsis, PIN-FORMED (PIN), auxin, cytokinins, root gravitropism,
- MeSH
- Arabidopsis drug effects physiology MeSH
- Models, Biological MeSH
- Biological Transport drug effects MeSH
- Cytokinins pharmacology MeSH
- Gravitation MeSH
- Gravitropism drug effects MeSH
- Plant Roots drug effects physiology MeSH
- Indoleacetic Acids metabolism MeSH
- Meristem drug effects physiology MeSH
- Arabidopsis Proteins metabolism MeSH
- Signal Transduction drug effects MeSH
- Green Fluorescent Proteins metabolism MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- AUX1 protein, Arabidopsis MeSH Browser
- Cytokinins MeSH
- Indoleacetic Acids MeSH
- Arabidopsis Proteins MeSH
- Green Fluorescent Proteins MeSH
Redirection of intercellular auxin fluxes via relocalization of the PIN-FORMED 3 (PIN3) and PIN7 auxin efflux carriers has been suggested to be necessary for the root gravitropic response. Cytokinins have also been proposed to play a role in controlling root gravitropism, but conclusive evidence is lacking. We present a detailed study of the dynamics of root bending early after gravistimulation, which revealed a delayed gravitropic response in transgenic lines with depleted endogenous cytokinins (Pro35S:AtCKX) and cytokinin signaling mutants. Pro35S:AtCKX lines, as well as a cytokinin receptor mutant ahk3, showed aberrations in the auxin response distribution in columella cells consistent with defects in the auxin transport machinery. Using in vivo real-time imaging of PIN3-GFP and PIN7-GFP in AtCKX3 overexpression and ahk3 backgrounds, we observed wild-type-like relocalization of PIN proteins in the columella early after gravistimulation, with gravity-induced relocalization of PIN7 faster than that of PIN3. Nonetheless, the cellular distribution of PIN3 and PIN7 and expression of PIN7 and the auxin influx carrier AUX1 was affected in AtCKX overexpression lines. Based on the retained cytokinin sensitivity in pin3 pin4 pin7 mutant, we propose the AUX1-mediated auxin transport rather than columella-located PIN proteins as a target of endogenous cytokinins in the control of root gravitropism.
CEITEC Central European Institute of Technology Masaryk University Brno CZ 62500 Czech Republic
Institute of Science and Technology Klosterneuburg AT 3400 Austria
References provided by Crossref.org
Cytokinin functions as an asymmetric and anti-gravitropic signal in lateral roots
What Has Been Seen Cannot Be Unseen-Detecting Auxin In Vivo
