AUXIN-BINDING-PROTEIN1 (ABP1) in phytochrome-B-controlled responses
Yunus Effendi1, Alan M Jones, Günther F E Scherer
1Leibniz Universität Hannover, Institut für Zierpflanzenbau und Gehölzforschung, Abt. Molekulare Ertragsphysiologie, Herrenhäuser Str. 2, D-30419 Hannover, Germany.
Journal of Experimental Botany
|September 21, 2013
Summary
The auxin receptor ABP1 and phytochrome light signaling pathways are genetically linked, regulating plant organ elongation and gene expression in response to light conditions. This research provides the first genetic evidence for their shared mechanism in plant growth.
Area of Science:
- Plant Biology
- Molecular Biology
- Genetics
Background:
- Auxin receptor ABP1 regulates plasma membrane activities and auxin transport.
- Phytochromes mediate red light's regulation of ABP1 levels and auxin-inducible growth.
- A genetic link between ABP1 and phytochrome regulation of organ elongation was previously unproven.
Purpose of the Study:
- To investigate the genetic relationship between ABP1 and phytochrome-mediated regulation of organ elongation.
- To determine if ABP1 and phytochrome signaling share common mechanisms for controlling plant growth.
- To elucidate the role of ABP1 in auxin and light signaling pathways.
Main Methods:
- Mutant analysis (abp1-5, abp1/ABP1, tir1-1, phyB-9, phyA-211) to assess hypocotyl elongation and gravitropism.
- Treatment with polar auxin transport inhibitor (NPA) under varying light conditions (WL, FR-enriched).
- Quantitative analysis of reporter gene expression for auxin- and shade-induced genes.
Main Results:
- Mutants lacking functional ABP1 showed increased hypocotyl length in far-red light, unlike tir1-1 mutants.
- Auxin transport inhibition (NPA) more strongly reduced elongation in low R:FR light, indicating auxin's role in FR-induced growth.
- ABP1 mutants exhibited reduced hypocotyl gravitropism and significantly lower expression of FR-induced genes compared to wild-type and phytochrome mutants.
Conclusions:
- ABP1 genetically interacts with phytochrome signaling pathways in regulating organ elongation.
- ABP1 plays a direct or indirect role in integrating auxin and light signals for plant development.
- The study provides genetic evidence for shared mechanisms between ABP1 and phytochrome in controlling hypocotyl growth and gene expression.
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