PIL5, a Phytochrome-Interacting bHLH Protein, Regulates Gibberellin Responsiveness by Binding Directly to theGAIandRGAPromoters inArabidopsisSeeds

Oh, Eunkyoo; Yamaguchi, Shinjiro; Hu, Jianhong; Jikumaru, Yusuke; Jung, Byunghyuck; Paik, Inyup; Lee, Jun Young; Sun, Tai; Kamiya, Yûji; Choi, Giltsu

doi:10.1105/tpc.107.050153

Cited by 421 publications

(550 citation statements)

References 67 publications

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“…Linearised plasmids encoding BRM, BRM , ATSWI3C and a PP2A PCR product were used to generate standard curves. The gene-speciWc primers used for BRM splice variant proWling and measurements of BRM and ATSWI3C expression levels, as well as for PP2A (as described previously by Oh et al 2007) are listed in Table S1. Final concentrations of qRT-PCR primers were 0.5 M and the annealing temperature was set at 60°C in all assays.…”

Section: Brm Antibody and Western Blottingmentioning

confidence: 99%

Genetic analysis of functional redundancy of BRM ATPase and ATSWI3C subunits of Arabidopsis SWI/SNF chromatin remodelling complexes

Archacki

Sarnowski

Halibart-Puzio

et al. 2009

Planta

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In yeast and mammals, ATP-dependent chromatin remodelling complexes of the SWI/SNF family play critical roles in the regulation of transcription, cell proliferation, diVerentiation and development. Homologues of conserved subunits of SWI/SNF-type complexes, including Snf2-type ATPases and SWI3-type proteins, participate in analogous processes in Arabidopsis. Recent studies indicate a remarkable similarity between phenotypic eVects of mutations in the SWI3 homologue ATSWI3C and bromodomain-ATPase BRM genes. To verify the extent of functional similarity between BRM and ATSWI3C, we have constructed atswi3c brm double mutants and compared their phenotypic traits to those of simultaneously grown single atswi3c and brm mutants. In addition to inheritance of characteristic developmental abnormalities shared by atswi3c and brm mutants, some additive brm-speciWc traits were also observed in the atswi3c brm double mutants. Unlike atswi3c, the brm mutation results in the enhancement of abnormal carpel development and pollen abortion leading to complete male sterility. Despite the overall similarity of brm and atswi3c phenotypes, a critical requirement for BRM in the diVerentiation of reproductive organs suggests that its regulatory functions do not entirely overlap those of ATSWI3C. The detection of two diVerent transcript isoforms indicates that BRM is regulated by alternative splicing that creates an in-frame premature translation stop codon in its SNF2-like ATPase coding domain. The analysis of Arabidopsis mutants in nonsense-mediated decay suggests an involvement of this pathway in the control of alternative BRM transcript level.

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Section: Brm Antibody and Western Blottingmentioning

confidence: 99%

Genetic analysis of functional redundancy of BRM ATPase and ATSWI3C subunits of Arabidopsis SWI/SNF chromatin remodelling complexes

Archacki

Sarnowski

Halibart-Puzio

et al. 2009

Planta

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“…A germination study of multiple DELLA protein mutants suggested that RGL2 is the predominant repressor of Arabidopsis seed germination in the light and GAI, RGA, and RGL1 enhance the function of RGL2 (Cao et al, 2005). Recently, RGA and GAI have been shown to play a role in inhibiting germination of dark-imbibed seeds in the absence of active phytochromes (Oh et al, 2007). DELLA proteins other than RGL2 may enhance RGL2 function also in supraoptimal temperature conditions.…”

Section: Function Of Ga Negative Regulators On Thermoinhibitionmentioning

confidence: 99%

High Temperature-Induced Abscisic Acid Biosynthesis and Its Role in the Inhibition of Gibberellin Action in Arabidopsis Seeds

et al. 2008

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Suppression of seed germination at supraoptimal high temperature (thermoinhibiton) during summer is crucial for Arabidopsis (Arabidopsis thaliana) to establish vegetative and reproductive growth in appropriate seasons. Abscisic acid (ABA) and gibberellins (GAs) are well known to be involved in germination control, but it remains unknown how these hormone actions (metabolism and responsiveness) are altered at high temperature. Here, we show that ABA levels in imbibed seeds are elevated at high temperature and that this increase is correlated with up-regulation of the zeaxanthin epoxidase gene ABA1/ZEP and three 9-cis-epoxycarotenoid dioxygenase genes, NCED2, NCED5, and NCED9. Reverse-genetic studies show that NCED9 plays a major and NCED5 and NCED2 play relatively minor roles in high temperature-induced ABA synthesis and germination inhibition. We also show that bioactive GAs stay at low levels at high temperature, presumably through suppression of GA 20-oxidase genes, GA20ox1, GA20ox2, and GA20ox3, and GA 3-oxidase genes, GA3ox1 and GA3ox2. Thermoinhibition-tolerant germination of loss-of-function mutants of GA negative regulators, SPINDLY (SPY) and RGL2, suggests that repression of GA signaling is required for thermoinibition. Interestingly, ABA-deficient aba2-2 mutant seeds show significant expression of GA synthesis genes and repression of SPY expression even at high temperature. In addition, the thermoinhibition-resistant germination phenotype of aba2-1 seeds is suppressed by a GA biosynthesis inhibitor, paclobutrazol. We conclude that high temperature stimulates ABA synthesis and represses GA synthesis and signaling through the action of ABA in Arabidopsis seeds.

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“…reported to control other light-regulated responses such as chlorophyll biosynthesis 27 or seed germination 28 -processes that are also known to be modulated by DELLAs. Hence, competitive interaction with members of the PIF family of transcription factors might be a prevailing mechanism for DELLA function, serving to explain the great diversity of responses controlled by these repressors.…”

Section: S-pif4mentioning

confidence: 99%

A molecular framework for light and gibberellin control of cell elongation

Lucas

Davière

Rodríguez-Falcón

et al. 2008

Nature

1,103

1,072

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Cell elongation during seedling development is antagonistically regulated by light and gibberellins (GAs) 1,2 . Light induces photomorphogenesis, leading to inhibition of hypocotyl growth, whereas GAs promote etiolated growth, characterized by increased hypocotyl elongation. The mechanism underlying this antagonistic interaction remains unclear. Here we report on the central role of the Arabidopsis thaliana nuclear transcription factor PIF4 (encoded by PHYTOCHROME INTERACTING FACTOR 4) 3 in the positive control of genes mediating cell elongation and show that this factor is negatively regulated by the light photoreceptor phyB (ref. 4) and by DELLA proteins that have a key repressor function in GA signalling 5 . Our results demonstrate that PIF4 is destabilized by phyB in the light and that DELLAs block PIF4 transcriptional activity by binding the DNA-recognition domain of this factor. We show that GAs abrogate such repression by promoting DELLA destabilization, and therefore cause a concomitant accumulation of free PIF4 in the nucleus. Consistent with this model, intermediate hypocotyl lengths were observed in transgenic plants over-accumulating both DELLAs and PIF4. Destabilization of this factor by phyB, together with its inactivation by DELLAs, constitutes a protein interaction framework that explains how plants integrate both light and GA signals to optimize growth and development in response to changing environments.Seedlings undergo alternative developmental programmes depending on whether they are germinated in the dark or in the light. Dark-grown seedlings exhibit etiolated growth, characterized by long hypocotyls, small and closed cotyledons with undifferentiated chloroplasts, and the repression of light-regulated genes 1 . During photomorphogenesis, light inhibits hypocotyl growth and promotes cotyledon opening and expansion, chloroplast differentiation and the activation of light-regulated genes. phyB is the main photoreceptor mediating de-etiolation in red light 4,6 . Absorption of red light converts this photoreceptor into a Pfr active form that is translocated into the nucleus 7,8 ; Pfr interacts there with members of the bHLH family of phytochrome-interacting factors (PIFs), involved in modulation of light-regulated genes with a role in photomorphogenesis 1,4 . Gibberellins (GAs) exert an opposite effect to light on photomorphogenesis 2 . GAs promote etiolated growth, whereas GA-deficiency induces a partially de-etiolated phenotype in the dark, which is reverted by a lack of DELLA function 2,9 . DELLAs function as key repressors of GA-responsive growth, by inhibiting GA-regulated gene expression 5 . These repressors accumulate in the nucleus and are rapidly degraded in response to GA 10,11 . In Arabidopsis, RGA (encoded by repressor of ga1-3) and GAI (encoded by GA insensitive) are the main repressors controlling hypocotyl growth and stem elongation 12,13 . Mutations within the DELLA domain render these proteins resistant to degradation, and result in a GA-insensitive dwarf phenotype 12,14 . This ...

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PIL5, a Phytochrome-Interacting bHLH Protein, Regulates Gibberellin Responsiveness by Binding Directly to theGAIandRGAPromoters inArabidopsisSeeds

Cited by 421 publications

References 67 publications

Genetic analysis of functional redundancy of BRM ATPase and ATSWI3C subunits of Arabidopsis SWI/SNF chromatin remodelling complexes

Genetic analysis of functional redundancy of BRM ATPase and ATSWI3C subunits of Arabidopsis SWI/SNF chromatin remodelling complexes

High Temperature-Induced Abscisic Acid Biosynthesis and Its Role in the Inhibition of Gibberellin Action in Arabidopsis Seeds

A molecular framework for light and gibberellin control of cell elongation

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