Abstract
BackgroundPerception and transduction of temperature changes result in altered growth enabling plants to adapt to increased ambient temperature. While PHYTOCHROME-INTERACTING FACTOR4 (PIF4) has been identified as a major ambient temperature signaling hub, its upstream regulation seems complex and is poorly understood. Here, we exploited natural variation for thermo-responsive growth in Arabidopsis thaliana using quantitative trait locus (QTL) analysis.ResultsWe identified GIRAFFE2.1, a major QTL explaining ~18 % of the phenotypic variation for temperature-induced hypocotyl elongation in the Bay-0 x Sha recombinant inbred line population. Transgenic complementation demonstrated that allelic variation in the circadian clock regulator EARLY FLOWERING3 (ELF3) is underlying this QTL. The source of variation could be allocated to a single nucleotide polymorphism in the ELF3 coding region, resulting in differential expression of PIF4 and its target genes, likely causing the observed natural variation in thermo-responsive growth.ConclusionsIn combination with other recent studies, this work establishes the role of ELF3 in the ambient temperature signaling network. Natural variation of ELF3-mediated gating of PIF4 expression during nightly growing periods seems to be affected by a coding sequence quantitative trait nucleotide that confers a selective advantage in certain environments. In addition, natural ELF3 alleles seem to differentially integrate temperature and photoperiod information to induce architectural changes. Thus, ELF3 emerges as an essential coordinator of growth and development in response to diverse environmental cues and implicates ELF3 as an important target of adaptation.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-015-0566-6) contains supplementary material, which is available to authorized users.
Highlights
Perception and transduction of temperature changes result in altered growth enabling plants to adapt to increased ambient temperature
A single nucleotide polymorphism in EARLY FLOWERING3 is underlying the GIR2.1 quantitative trait locus (QTL) Knowing that a diurnal photoperiod was a prerequisite for temperature-induced hypocotyl elongation (TIHE) differences between Bay-0 and Sha (Fig. 2b), we identified EARLY FLOWERING3 (ELF3) as a candidate gene located in the GIR2.1 target interval
Natural variation in thermomorphogenesis caused by ELF3 variants could be mediated at several levels
Summary
Perception and transduction of temperature changes result in altered growth enabling plants to adapt to increased ambient temperature. While PHYTOCHROME-INTERACTING FACTOR4 (PIF4) has been identified as a major ambient temperature signaling hub, its upstream regulation seems complex and is poorly understood. Hypocotyl elongation [2] and leaf hyponasty [3] belong to the most sensitive thermomorphogenic changes in plant development. These coordinated responses likely enhance evaporative leaf cooling [4, 5] and. PIF4 protein binds to the promoters of auxin biosynthesis and response genes [6,7,8,9] It thereby transcriptionally activates auxin responses, resulting in elongation growth. PIF4 itself seems to be transcriptionally regulated in a temperature-dependent manner by the bZIP transcription factor ELONGATED HYPOCOTYL5 (HY5) [10]
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