Expression Of PHYTOCHROME-INTERACTING FACTOR4 Research Articles

Cell wall integrity modulates HOOKLESS1 and PHYTOCHROME INTERACTING FACTOR4 expression controlling apical hook formation.

Formation of the apical hook in etiolated dicot seedlings results from differential growth in the hypocotyl apex and is tightly controlled by environmental cues and hormones, among which auxin and gibberellins (GAs) play an important role. Cell expansion is tightly regulated by the cell wall, but whether and how feedback from this structure contributes to hook development is still unclear. Here, we show that etiolated seedlings of the Arabidopsis (Arabidopsis thaliana) quasimodo2-1 (qua2) mutant, defective in pectin biosynthesis, display severe defects in apical hook formation and maintenance, accompanied by loss of asymmetric auxin maxima and of differential cell expansion. Moreover, qua2 seedlings show reduced expression of HOOKLESS 1 (HLS1) and PHYTOCHROME INTERACTING FACTOR 4 (PIF4), which are positive regulators of hook formation. Treatment of wild-type seedlings with the cellulose inhibitor isoxaben (isx) also prevents hook development and represses HLS1 and PIF4 expression. Exogenous GAs, loss of DELLA proteins or HLS1 overexpression partially restore hook development in qua2 and isx-treated seedlings. Interestingly, increased agar concentration in the medium restores, both in qua2 and isx-treated seedlings, hook formation, asymmetric auxin maxima and PIF4 and HLS1 expression. Analysis of plants expressing a FRET-based GA sensor indicate that isx reduces accumulation of GAs in the apical hook region in a turgor-dependent manner. Lack of the cell wall integrity sensor THESEUS 1, which modulates turgor loss point, restores hook formation in qua2 and isx-treated seedlings. We propose that turgor-dependent signals link changes in cell wall integrity to the PIF4-HLS1 signalling module to control differential cell elongation during hook formation.

A warm temperature-released negative feedback loop fine-tunes PIF4-mediated thermomorphogenesis in Arabidopsis

Plants can sense temperature changes and adjust their growth accordingly. In Arabidopsis, high ambient temperatures stimulate stem elongation by activating a key thermoresponsive regulator, PHYTOCHROME INTERACTING FACTOR 4 (PIF4). Here, we show that warmth promotes the nighttime transcription of GI, which is necessary for the high temperature-induced transcription of TOC1. Genetic analyses suggest that GI prevents excessive thermoresponsive growth by inhibiting PIF4, with this regulatory mechanism being partially reliant on TOC1. GI transcription is repressed by ELF3 and HY5, which concurrently inhibit PIF4 expression and activity. Temperature elevation causes the deactivation or degradation of ELF3 and HY5, leading to PIF4 activation and relief of GI transcriptional repression at high temperatures. This allows PIF4 to further activate GI transcription in response to elevated temperatures. GI, in turn, inhibits PIF4, establishing a negative feedback loop that fine-tunes PIF4 activity. In addition, we demonstrate that ELF3, HY5, and PIF4 regulate GI transcription by modulating the enrichment of histone variant H2A.Z at the GI locus. Together, our findings suggest that thermal release of a negative feedback loop finely adjusts plant thermomorphogenesis.

High temperature inhibits vascular development via the PIF4-miR166-HB15 module in Arabidopsis

The plant vascular system is an elaborate network of conducting and supporting tissues that extends throughout the plant body, and its structure and function must be orchestrated with different environmental conditions. Under high temperature, plants display thin and lodging stems that may lead to decreased yield and quality of crops. However, the molecular mechanism underlying high-temperature-mediated regulation of vascular development is not known. Here, we show that Arabidopsis plants overexpressing the basic-helix-loop-helix (bHLH) transcription factor PHYTOCHROME INTERACTING FACTOR 4 (PIF4), a central regulator of high-temperature signaling, display fewer vascular bundles (VBs) and decreased secondary cell wall (SCW) thickening, mimicking the lodging inflorescence stems of high-temperature-grown wild-type plants. Rising temperature and elevated PIF4 expression reduced the expression of MIR166 and, concomitantly, elevated the expression of the downstream class III homeodomain leucine-zipper (HD-ZIP III) family gene HB15. Consistently, knockdown of miR166 and overexpression of HB15 led to inhibition of vascular development and SCW formation, whereas the hb15 mutant displayed the opposite phenotype in response to high temperature. Moreover, invitro and invivo assays verified that PIF4 binds to the promoters of several MIR166 genes and represses their expression. Our study establishes a direct functional link between PIF4 and the miR166-HB15 module in modulating vascular development and SCW thickening and consequently stem-lodging susceptibility at elevated temperatures.

MYB112 connects light and circadian clock signals to promote hypocotyl elongation in Arabidopsis.

Ambient light and the endogenous circadian clock play key roles in regulating Arabidopsis (Arabidopsis thaliana) seedling photomorphogenesis. PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) acts downstream of both light and the circadian clock to promote hypocotyl elongation. Several members of the R2R3-MYB transcription factor (TF) family, the most common type of MYB TF family in Arabidopsis, have been shown to be involved in regulating photomorphogenesis. Nonetheless, whether R2R3-MYB TFs are involved in connecting the light and clock signaling pathways during seedling photomorphogenesis remains unknown. Here, we report that MYB112, a member of the R2R3-MYB family, acts as a negative regulator of seedling photomorphogenesis in Arabidopsis. The light signal promotes the transcription and protein accumulation of MYB112. myb112 mutants exhibit short hypocotyls in both constant light and diurnal cycles. MYB112 physically interacts with PIF4 to enhance the transcription of PIF4 target genes involved in the auxin pathway, including YUCCA8 (YUC8), INDOLE-3-ACETIC ACID INDUCIBLE 19 (IAA19), and IAA29. Furthermore, MYB112 directly binds to the promoter of LUX ARRHYTHMO (LUX), the central component of clock oscillators, to repress its expression mainly in the afternoon and relieve LUX-inhibited expression of PIF4. Genetic evidence confirms that LUX acts downstream of MYB112 in regulating hypocotyl elongation. Thus, the enhanced transcript accumulation and transcriptional activation activity of PIF4 by MYB112 additively promotes the expression of auxin-related genes, thereby increasing auxin synthesis and signaling and fine-tuning hypocotyl growth under diurnal cycles.

ZTL regulates thermomorphogenesis through TOC1 and PRR5.

Plants adapt to high temperature stresses through thermomorphogenesis, a process that includes stem elongation and hyponastic leaf growth. Thermomorphogenesis is gated by the circadian clock through two evening-expressed clock components, TIMING OF CAB EXPRESSION1(TOC1) and PSEUDO-RESPONSE REGULATORS5(PRR5). These proteins directly interact with and inhibit PHYTOCHROME INTERACTING FACTOR4(PIF4), a basic helix-loop-helix transcription factor that promotes thermoresponsive growth. PIF4-mediated thermoresponsive growth is positively regulated by ZEITLUPE(ZTL), a central clock component, but the molecular mechanisms underlying this are poorly understood. Here, we show that ZTL regulates thermoresponsive growth through TOC1 and PRR5. Genetic analyses reveal that ZTL regulates PIF4 activity as well as PIF4 expression. In Arabidopsis thaliana, ztl mutants exhibit highly accumulated TOC1 and PRR5 and unresponsive expression of PIF4 target genes under exposure to high temperatures. Mutations in TOC1 and PRR5 restore thermoactivation of PIF4 target genes and thermoresponsive growth in ztl mutants. We also show that the molecular chaperone heat-shock protein90 promotes thermoresponsive growth through the ZTL-TOC1/PRR5 signaling module. Further, we show that ZTL protein stability is increased at high temperatures. Taken together, our results demonstrate that ZTL-mediated degradation of TOC1 and PRR5 enhances the sensitivity of hypocotyl growth to high temperatures.

CRISPR/Cas9-mediated AtGATA25 mutant represents a novel model for regulating hypocotyl elongation in Arabidopsis thaliana

BackgroundPlants have evolved to adapt to the ever-changing environments through various morphological changes. An organism anticipates and responds to changes in its environment via the circadian clock, an endogenous oscillator lasting approximately 24 h. The circadian clock regulates various physiological processes, such as hypocotyl elongation in Arabidopsis thaliana. Phytochrome interacting factor 4 (PIF4), a member of the bHLH protein family, plays a vital hub role in light signaling pathways and temperature-mediated growth response mechanisms. PIF4 is controlled by the circadian clock and interacts with several factors. However, the components that regulate PIF4 transcription and activity are not clearly understood.Methods and ResultsHere, we showed that the Arabidopsis thaliana GATA25 (AtGATA25) transcription factor plays a fundamental role in promoting hypocotyl elongation by positively regulating the expression of PIF4. This was confirmed to in the loss-of-function mutant of AtGATA25 via CRISPR/Cas9-mediated gene editing, which inhibits hypocotyl elongation and decreases the expression of PIF4. In contrast, the overexpression of AtGATA25 in transgenic plants resulted in increased expression of PIF4 and enhanced hypocotyl elongation. To better understand AtGATA25-mediated PIF4 transcriptional regulation, we analyzed the promoter region of the target gene PIF4 and characterized the role of GATA25 through transcriptional activation analysis.ConclusionOur findings suggest a novel role of the AtGATA25 transcription factor in hypocotyl elongation.

FLS2-RBOHD-PIF4 Module Regulates Plant Response to Drought and Salt Stress.

As sessile organisms, plants are constantly challenged by several environmental stresses. Different kinds of stress often occur simultaneously, leading to the accumulation of reactive oxygen species (ROS) produced by respiratory burst oxidase homolog (RBOHD) and calcium fluctuation in cells. Extensive studies have revealed that flagellin sensitive 2 (FLS2) can sense the infection by pathogenic microorganisms and activate cellular immune response by regulating intracellular ROS and calcium signals, which can also be activated during plant response to abiotic stress. However, little is known about the roles of FLS2 and RBOHD in regulating abiotic stress. In this study, we found that although the fls2 mutant showed tolerance, the double mutant rbohd rbohf displayed hypersensitivity to abiotic stress, similar to its performance in response to immune stress. An analysis of the transcriptome of the fls2 mutant and rbohd rbohf double mutant revealed that phytochrome interacting factor 4 (PIF4) acted downstream of FLS2 and RBOHD to respond to the abiotic stress. Further analysis showed that both FLS2 and RBOHD regulated the response of plants to drought and salt stress by regulating the expression of PIF4. These findings revealed an FLS2–RBOHD–PIF4 module in regulating plant response to biotic and abiotic stresses.

ZEITLUPE enhances expression of PIF4 and YUC8 in the upper aerial parts of Arabidopsis seedlings to positively regulate hypocotyl elongation.

Microarray and genetic analyses reveal that ZTL induces the expression of genes related to auxin synthesis, thereby promoting hypocotyl elongation. ZTL is a blue-light receptor that possesses a light-oxygen-voltage-sensing (LOV) domain, an F-box motif, and a kelch repeat domain. ZTL promotes hypocotyl elongation under high temperature (28°C) in Arabidopsis thaliana; however, the mechanism of this regulation is unknown. Here, we divided seedlings into hypocotyls and upper aerial parts, and performed microarray analyses. In hypocotyl, 1062 genes were down-regulated in ztl mutants (ztl-3 and ztl-105) compared with wild type; some of these genes encoded enzymes involved in cell wall modification, consistent with reduced hypocotyl elongation. In upper aerial parts, 1038 genes were down-regulated in the ztl mutants compared with wild type; these included genes involved in auxin synthesis and auxin response. Furthermore, the expression of the PHYTOCHROME INTERACTING FACTOR 4 (PIF4) gene, which encodes a transcription factor known to positively regulate YUCCA genes (YUCs), was also decreased in the ztl mutants. Genetic analysis revealed that overexpression of PIF4 and YUC8 could restore the suppressed hypocotyl length in the ztl mutants. Our results suggest that ZTL induces expression of YUC8 via PIF4 in upper aerial parts and promotes hypocotyl elongation.

COLD-REGULATED GENE27 Integrates Signals from Light and the Circadian Clock to Promote Hypocotyl Growth in Arabidopsis.

Light and the circadian clock are two essential external and internal cues affecting seedling development. COLD-REGULATED GENE27 (COR27), which is regulated by cold temperatures and light signals, functions as a key regulator of the circadian clock. Here, we report that COR27 acts as a negative regulator of light signaling. COR27 physically interacts with the CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1)-SUPPRESSOR OF PHYTOCHROME A1 (SPA1) E3 ubiquitin ligase complex and undergoes COP1-mediated degradation via the 26S proteasome system in the dark. cor27 mutant seedlings exhibit shorter hypocotyls, while transgenic lines overexpressing COR27 show elongated hypocotyls in the light. In addition, light induces the accumulation of COR27. On one hand, accumulated COR27 interacts with ELONGATED HYPOCOTYL5 (HY5) to repress HY5 DNA binding activity. On the other hand, COR27 associates with the chromatin at the PHYTOCHROME INTERACTING FACTOR4 (PIF4) promoter region and upregulates PIF4 expression in a circadian clock-dependent manner. Together, our findings reveal a mechanistic framework whereby COR27 represses photomorphogenesis in the light and provide insights toward how light and the circadian clock synergistically control hypocotyl growth.

TCP Transcription Factors Associate with PHYTOCHROME INTERACTING FACTOR 4 and CRYPTOCHROME 1 to Regulate Thermomorphogenesis in Arabidopsis thaliana

SummaryTemperature, one of the most critical environmental cues, greatly affects plant growth, development, and reproduction. PHYTOCHROME-INTERACTING FACTOR 4 (PIF4), a key transcription factor in light signaling pathway, plays a central role in temperature-mediated growth responses. How higher temperature regulates the function of PIF4, however, is not well understood. Here we demonstrate that three phylogenetically related TEOSINTE BRANCHED 1/CYCLOIDEA/PCF (TCP) transcription factors, TCP5, TCP13, and TCP17, play fundamental roles in promoting thermoresponsive hypocotyl growth by positively regulating the activity of PIF4. TCP17 was found to interact with a blue light receptor, CRYPTOCHROME 1 (CRY1), at lower temperature, leading to reduced activity of TCP17. Higher temperature can increase the stability of TCP17, and release TCP17 from the CRY1-TCP17 complex, allowing it to upregulate the expression of PIF4 and enhance the transcriptional activity of PIF4. This study revealed the important roles of TCPs in regulating the activity of PIF4 in thermomorphogenesis.

COP1 SUPPRESSOR 4 promotes seedling photomorphogenesis by repressing CCA1 and PIF4 expression in Arabidopsis

CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1) and DE-ETIOLATED 1 (DET1) are founding components of two central repressor complexes of photomorphogenesis that trigger the degradation of a larger number of photomorphogenic-promoting factors in darkness. Here, we identify COP1 SUPPRESSOR 4 (CSU4) as a genetic suppressor of the cop1-6 mutation. Mutations in CSU4 largely rescued the constitutively photomorphogenic phenotype of cop1-6 and det1-1 in darkness. Loss of CSU4 function resulted in significantly longer hypocotyl in the light. Further biochemical studies revealed that CSU4 physically interacts with CIRCADIAN CLOCK-ASSOCIATED 1 (CCA1) and negatively regulates its transcriptional repression activity toward its targets. CSU4 represses the expression of CCA1 in the early morning and of PHYTOCHROME INTERACTING FACTOR 4 (PIF4) in the early evening. Our study suggests that CSU4 acts as a negative regulator of CCA1 via physically associating with CCA1, which in turn, likely serves to repress expression of CCA1 and PIF4 to promote photomorphogenesis.

DET1 and HY5 Control PIF4-Mediated Thermosensory Elongation Growth through Distinct Mechanisms

SummaryPlant growth and development are defined by environmental cues. The transcription factor PHYTOCHROME INTERACTING FACTOR 4 (PIF4) is the central signaling hub that integrates environmental cues, including light and temperature, to regulate growth and development. The thermosensory mechanisms controlling the PIF4-mediated temperature response, and its integration with other environmental responses, remain poorly understood. DE-ETIOLATED 1 (DET1) and CONSTITUTIVE PHOTOMORPHOGENESIS 1 (COP1), key regulators of light signaling, have been proposed to control thermosensory growth by transcriptional regulation of PIF4, through ELONGATED HYPOCOTYL 5 (HY5). Here, we show that DET1/COP1 and HY5 regulate thermosensory elongation through distinct mechanisms. DET1 and COP1 are essential for promoting PIF4 expression and stabilizing PIF4 protein. Furthermore, HY5 inhibits elongation growth through competitive chromatin binding to PIF4 targets, not through transcriptional regulation of PIF4. Our findings reveal a mechanistic framework in which DET1/COP1 and HY5 regulatory modules act independently to regulate growth through the environmental signal integrator PIF4.

Local Transcriptional Control of YUCCA Regulates Auxin Promoted Root-Growth Inhibition in Response to Aluminium Stress in Arabidopsis.

Auxin is necessary for the inhibition of root growth induced by aluminium (Al) stress, however the molecular mechanism controlling this is largely unknown. Here, we report that YUCCA (YUC), which encodes flavin monooxygenase-like proteins, regulates local auxin biosynthesis in the root apex transition zone (TZ) in response to Al stress. Al stress up-regulates YUC3/5/7/8/9 in the root-apex TZ, which we show results in the accumulation of auxin in the root-apex TZ and root-growth inhibition during the Al stress response. These Al-dependent changes in the regulation of YUCs in the root-apex TZ and YUC-regulated root growth inhibition are dependent on ethylene signalling. Increasing or disruption of ethylene signalling caused either enhanced or reduced up-regulation, respectively, of YUCs in root-apex TZ in response to Al stress. In addition, ethylene enhanced root growth inhibition under Al stress was strongly alleviated in yuc mutants or by co-treatment with yucasin, an inhibitor of YUC activity, suggesting a downstream role of YUCs in this process. Moreover, ethylene-insensitive 3 (EIN3) is involved into the direct regulation of YUC9 transcription in this process. Furthermore, we demonstrated that PHYTOCHROME INTERACTING FACTOR4 (PIF4) functions as a transcriptional activator for YUC5/8/9. PIF4 promotes Al-inhibited primary root growth by regulating the local expression of YUCs and auxin signal in the root-apex TZ. The Al–induced expression of PIF4 in root TZ acts downstream of ethylene signalling. Taken together, our results highlight a regulatory cascade for YUCs-regulated local auxin biosynthesis in the root-apex TZ mediating root growth inhibition in response to Al stress.

Enhancement of hypocotyl elongation by LOV KELCH PROTEIN2 production is mediated by auxin and phytochrome-interacting factors in Arabidopsis thaliana.

Auxin and two phytochrome-interacting factors, PHYTOCHROME-INTERACTING FACTOR4 (PIF4) and PIF5, play crucial roles in the enhancement of hypocotyl elongation in transgenic Arabidopsis thaliana plants that overproduce LOV KELCH PROTEIN2 (LKP2). LOV KELCH PROTEIN2 (LKP2) is a positive regulator of hypocotyl elongation under white light in Arabidopsis thaliana. In this study, using microarray analysis, we compared the gene expression profiles of hypocotyls of wild-type Arabidopsis (Columbia accession), a transgenic line that produces green fluorescent protein (GFP), and two lines that produce GFP-tagged LKP2 (GFP-LKP2). We found that, in GFP-LKP2 hypocotyls, 775 genes were up-regulated, including 36 auxin-responsive genes, such as 27 SMALL AUXIN UP RNA (SAUR) and 6 AUXIN/INDOLE-3-ACETIC ACID (AUX/IAA) genes, and 21 genes involved in responses to red or far-red light, including PHYTOCHROME-INTERACTING FACTOR4 (PIF4) and PIF5; and 725 genes were down-regulated, including 15 flavonoid biosynthesis genes. Hypocotyls of GFP-LKP2 seedlings, but not cotyledons or roots, contained a higher level of indole-3-acetic acid (IAA) than those of control seedlings. Auxin inhibitors reduced the enhancement of hypocotyl elongation in GFP-LKP2 seedlings by inhibiting the increase in cortical cell number and elongation of the epidermal and cortical cells. The enhancement of hypocotyl elongation was completely suppressed in progeny of the crosses between GFP-LKP2 lines and dominant gain-of-function auxin-resistant mutants (axr2-1 and axr3-1) or loss-of-function mutants pif4, pif5, and pif4 pif5. Our results suggest that the enhancement of hypocotyl elongation in GFP-LKP2 seedlings is due to the elevated level of IAA and to the up-regulated expression of PIF4 and PIF5 in hypocotyls.

Natural variants of ELF3 affect thermomorphogenesis by transcriptionally modulating PIF4-dependent auxin response genes

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.

The Transcriptional Regulator BBX19 Promotes Hypocotyl Growth by Facilitating COP1-Mediated EARLY FLOWERING3 Degradation in Arabidopsis.

Hypocotyl elongation is a highly coordinated physiological response regulated by myriad internal and external cues. Here, we show that BBX19, a transcriptional regulator with two B-box motifs, is a positive regulator of growth; diminished BBX19 expression by RNA interference reduces hypocotyl length, and its constitutive expression promotes growth. This function of BBX19 is dependent on the E3 ubiquitin ligase CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1), EARLY FLOWERING3 (ELF3), and PHYTOCHROME-INTERACTING FACTOR4 (PIF4) and PIF5. BBX19 is nucleus-colocalized and interacts physically with COP1 and ELF3, a component of the evening complex that represses the expression of PIF4 and PIF5. Moreover, ELF3 protein abundance inversely correlates with BBX19 expression levels in a COP1-dependent manner. By contrast, PIF expression, coinciding with the initiation of hypocotyl growth in the early evening, is positively correlated with the BBX19 transcript abundance. These results collectively establish BBX19 as an adaptor that binds to and recruits ELF3 for degradation by COP1 and, as such, dynamically gates the formation of the evening complex, resulting in derepression of PIF4/5. This finding refines our perspective on how plants grow by providing a molecular link between COP1, ELF3, and PIF4/5 as an underlying mechanism of photomorphogenic development in Arabidopsis thaliana.

Differentially phased leaf growth and movements in Arabidopsis depend on coordinated circadian and light regulation.

In contrast to vastly studied hypocotyl growth, little is known about diel regulation of leaf growth and its coordination with movements such as changes in leaf elevation angle (hyponasty). We developed a 3D live-leaf growth analysis system enabling simultaneous monitoring of growth and movements. Leaf growth is maximal several hours after dawn, requires light, and is regulated by daylength, suggesting coupling between growth and metabolism. We identify both blade and petiole positioning as important components of leaf movements in Arabidopsis thaliana and reveal a temporal delay between growth and movements. In hypocotyls, the combination of circadian expression of PHYTOCHROME INTERACTING FACTOR4 (PIF4) and PIF5 and their light-regulated protein stability drives rhythmic hypocotyl elongation with peak growth at dawn. We find that PIF4 and PIF5 are not essential to sustain rhythmic leaf growth but influence their amplitude. Furthermore, EARLY FLOWERING3, a member of the evening complex (EC), is required to maintain the correct phase between growth and movement. Our study shows that the mechanisms underlying rhythmic hypocotyl and leaf growth differ. Moreover, we reveal the temporal relationship between leaf elongation and movements and demonstrate the importance of the EC for the coordination of these phenotypic traits.