Gibberellin-Mediated Proteasome-Dependent Degradation of the Barley DELLA Protein SLN1 Repressor

Fu, Xiang‐Dong; Richards, Donald E.; Aït-Ali, Tahar; Hynes, Llewelyn W.; Ougham, Helen J.; Peng, Jinrong; Harberd, Nicholas P.

doi:10.1105/tpc.006197

Cited by 258 publications

(199 citation statements)

References 69 publications

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“…GA increases growth by causing degradation of DELLA growth repressor proteins, and also through DELLA-independent mechanisms (Peng et al, 1997;Fu et al, 2002;Cheng et al, 2004;Cao et al, 2006). Therefore, we investigated the involvement of DELLA proteins in Suc-induced hypocotyl elongation under light/ dark cycles.…”

Section: Phytohormone Signaling and Suc-induced Hypocotyl Elongation mentioning

confidence: 99%

“…Therefore, we investigated the involvement of DELLA proteins in Suc-induced hypocotyl elongation under light/ dark cycles. The gai-1 mutant harbors a deletion within the DELLA domain of GIBBERELLIC ACID INSENSI-TIVE (GAI), which prevents GA-induced proteasomal degradation of GAI (Peng et al, 1997;Fu et al, 2002). Under 4-h photoperiods, Suc supplementation increased hypocotyl length in gai-1, but the magnitude of Suc-induced elongation in gai-1 was reduced compared with the wild type (hypocotyls became 36.5% longer in gai-1 in response to Suc, compared with 59.2% longer in the wild type; Fig.…”

Section: Phytohormone Signaling and Suc-induced Hypocotyl Elongation mentioning

confidence: 99%

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The Energy-Signaling Hub SnRK1 Is Important for Sucrose-Induced Hypocotyl Elongation

et al. 2017

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Emerging seedlings respond to environmental conditions such as light and temperature to optimize their establishment. Seedlings grow initially through elongation of the hypocotyl, which is regulated by signaling pathways that integrate environmental information to regulate seedling development. The hypocotyls of Arabidopsis (Arabidopsis thaliana) also elongate in response to sucrose. Here, we investigated the role of cellular sugar-sensing mechanisms in the elongation of hypocotyls in response to Suc. We focused upon the role of SnRK1, which is a sugar-signaling hub that regulates metabolism and transcription in response to cellular energy status. We also investigated the role of TPS1, which synthesizes the signaling sugar trehalose-6-P that is proposed to regulate SnRK1 activity. Under light/dark cycles, we found that Suc-induced hypocotyl elongation did not occur in tps1 mutants and overexpressors of KIN10 (AKIN10/SnRK1.1), a catalytic subunit of SnRK1. We demonstrate that the magnitude of Suc-induced hypocotyl elongation depends on the day length and light intensity. We identified roles for auxin and gibberellin signaling in Suc-induced hypocotyl elongation under short photoperiods. We found that Suc-induced hypocotyl elongation under light/dark cycles does not involve another proposed sugar sensor, HEXOKINASE1, or the circadian oscillator. Our study identifies novel roles for KIN10 and TPS1 in mediating a signal that underlies Suc-induced hypocotyl elongation in light/dark cycles.

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Section: Phytohormone Signaling and Suc-induced Hypocotyl Elongation mentioning

confidence: 99%

Section: Phytohormone Signaling and Suc-induced Hypocotyl Elongation mentioning

confidence: 99%

The Energy-Signaling Hub SnRK1 Is Important for Sucrose-Induced Hypocotyl Elongation

et al. 2017

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“…As key repressors of GA-responsive growth, DELLA proteins accumulate in the nucleus and are rapidly degraded in response to GA (Silverstone et al, 2001;Fu et al, 2002). A key question regarding the function of DELLA proteins, which do not have a DNA-binding domain, is how they regulate downstream genes, thus mediating the growth restraint on plants.…”

Section: Rga Regulates Flower Development By Activating Stress-relatementioning

confidence: 99%

Global Identification of DELLA Target Genes during Arabidopsis Flower Development

Hou

Shen

et al. 2008

Plant Physiology

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Gibberellin (GA) plays important roles in regulating many aspects of plant development. GA derepresses its signaling pathway by promoting the degradation of DELLA proteins, a family of nuclear growth repressors. Although the floral organ identity is established in flowers of the GA-deficient mutant ga1-3, the growth of all floral organs is severely retarded. In particular, abortive anther development in ga1-3 results in male sterility. Genetic analysis has revealed that various combinations of null mutants of DELLA proteins could gradually rescue floral organ defects in ga1-3 and that RGA is the most important DELLA protein involved in floral organ development. To elucidate the early molecular events controlled by RGA during flower development, we performed whole-genome microarray analysis to identify genes in response to the steroid-inducible activation of RGA in ga1-3 rgl2 rga 35S:RGA-GR. Although DELLA proteins were suggested as transcriptional repressors, similar numbers of genes were down-regulated or up-regulated by RGA during floral organ development. More than one-third of RGA down-regulated genes were specifically or predominantly expressed in stamens. A significant number of RGA-regulated genes are involved in phytohormone signaling or stress response. Further expression analysis through activation of RGA by steroid induction combined with cycloheximide identified eight genes as immediate targets of RGA. In situ hybridization and transgenic studies further showed that the expression pattern and function of several selected genes were consistent with the predictions from microarray analysis. These results suggest that DELLA regulation of floral organ development is modulated by multiple phytohormones and stress signaling pathways.

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“…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 .…”

mentioning

confidence: 99%

A molecular framework for light and gibberellin control of cell elongation

Lucas

Davière

Rodríguez-Falcón

et al. 2008

Nature

1,087

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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Gibberellin-Mediated Proteasome-Dependent Degradation of the Barley DELLA Protein SLN1 Repressor

Cited by 258 publications

References 69 publications

The Energy-Signaling Hub SnRK1 Is Important for Sucrose-Induced Hypocotyl Elongation

The Energy-Signaling Hub SnRK1 Is Important for Sucrose-Induced Hypocotyl Elongation

Global Identification of DELLA Target Genes during Arabidopsis Flower Development

A molecular framework for light and gibberellin control of cell elongation

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