A Study of Gibberellin Homeostasis and Cryptochrome-Mediated Blue Light Inhibition of Hypocotyl Elongation

Zhao, Xiaoying; Yu, Xuhong; Foo, Eloise; Symons, Gregory M.; Lopez, Javier; Bendehakkalu, Krishnaprasad T.; Xiang, Jing; Weller, James L.; Liu, Xuanming; Reid, James B.; Lin, Chentao

doi:10.1104/pp.107.099838

Cited by 149 publications

(174 citation statements)

References 64 publications

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“…The main target of LONG1-dependent light regulation appears to be GA2ox2, consistent with the conclusions of Reid et al (2002), although smaller effects on other genes may also contribute. Induction of Arabidopsis GA2ox genes by light has also recently been reported (Achard et al, 2007;Zhao et al, 2007;Alabadí et al, 2008), and Arabidopsis GA2ox1 was also found to be HY5-regulated in transcript profiling studies (Sibout et al, 2006;Lee et al, 2007). These findings suggest that Arabidopsis HY5 may play a similar role in light regulation of the GA pathway, although this has yet to be directly tested.…”

Section: Long1 and Light Regulation Of Ga Biosynthesissupporting

confidence: 54%

Light Regulation of Gibberellin Biosynthesis in Pea Is Mediated through the COP1/HY5 Pathway

et al. 2009

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Light regulation of gibberellin (GA) biosynthesis occurs in several species, but the signaling pathway through which this occurs has not been clearly established. We have isolated a new pea (Pisum sativum) mutant, long1, with a light-dependent elongated phenotype that is particularly pronounced in the epicotyl and first internode. The long1 mutation impairs signaling from phytochrome and cryptochrome photoreceptors and interacts genetically with a mutation in LIP1, the pea ortholog of Arabidopsis thaliana COP1. Mutant long1 seedlings show a dramatic impairment in the light regulation of active GA levels and the expression of several GA biosynthetic genes, most notably the GA catabolism gene GA2ox2. The long1 mutant carries a nonsense mutation in a gene orthologous to the ASTRAY gene from Lotus japonicus, a divergent ortholog of the Arabidopsis bZIP transcription factor gene HY5. Our results show that LONG1 has a central role in mediating the effects of light on GA biosynthesis in pea and demonstrate the importance of this regulation for appropriate photomorphogenic development. By contrast, LONG1 has no effect on GA responsiveness, implying that interactions between LONG1 and GA signaling are not a significant component of the molecular framework for light–GA interactions in pea.

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Section: Long1 and Light Regulation Of Ga Biosynthesissupporting

confidence: 54%

Light Regulation of Gibberellin Biosynthesis in Pea Is Mediated through the COP1/HY5 Pathway

et al. 2009

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“…The GA 3 biosynthesis in low and high nitrate The endogenous GA levels are not constant level during different time points in wild type Arabidopsis in light/dark cycles (Hisamatsu et al 2005;Zhao et al 2007). It oscillates in a diurnal or in a clock-controlled manner (Figs 3a, c).…”

Section: Resultsmentioning

confidence: 97%

Nitrate or NaCl regulates floral induction in Arabidopsis thaliana

Hou

Ren

et al. 2013

Biologia

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Flowering, the transition from the vegetative to reproductive phase in plants, is regulated by both endogenous and environmental signals. Exposure to an extended period of stress (such as low nitrate or NaCl) can also promote flowering in many species, but little is known about how these forms of stress regulate floral induction. In this study, we found that stress induced by low concentrations of nitrate or NaCl activated the biosynthesis of gibberellin (GA) as evidenced by increased expression of the GA biosynthetic enzyme GA1. Expression of CO and SOC1 were also enhanced, leading to an acceleration of flowering. The effects of nitrate and NaCl on the photoperiod pathway were distinct, however. Two genes related to the photoperiod pathway, CCA1 and LHY, were repressed only under low NaCl treatment, while expression was unaltered by nitrate. Therefore, we suggest that the biosynthesis of gibberellin (GA) may play an important role in integrating signals induced by exogenous stress to regulate flowering in Arabidopsis.

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“…Under GAdeficient conditions, photomorphogenesis is partially de-repressed in the dark (Alabadi et al, 2004). In addition, blue light inhibits GA20ox1 and GA3ox1 expression whereas it increases GA2ox1 expression in de-etiolated seedling (Zhao et al, 2007). These changes in GA metabolism genes correlate with transient reduction in GA 4 levels.…”

Section: Light Regulation During Photomorphogenesismentioning

confidence: 96%

Gibberellin Metabolism, Perception and Signaling Pathways in Arabidopsis

Sun

2008

The Arabidopsis Book

218

195

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Bioactive gibberellins (GAs) are diterpene phytohormones that modulate growth and development throughout the whole life cycle of the plant. Arabidopsis genes encoding most GA biosynthesis and catabolism enzymes, as well as GA receptors (GIBBERELLIN INSENSITIVE DWARF1, GID1) and early GA signaling components have been identified. Expression studies on the GA biosynthesis genes are beginning to reveal the potential sites of GA biosynthesis during plant development. Biochemical and genetic analyses demonstrate that GA de-represses its signaling pathway by binding to GID1s, which induce degradation of GA signaling repressors (DELLAs) via an ubiquitin-proteasome pathway. To modulate plant growth and development, the GA pathway is also regulated by endogenous signals (other hormones) and environmental cues (such as light, temperature and salt stress). In many cases, these internal and external cues directly affect GA metabolism and bioactive GA levels, and indirectly alter DELLA accumulation and GA responses. Importantly, direct negative interaction between DELLA and PIF3 and PIF4 (2 phytochrome interacting transcription factors) appears to integrate the effects of light and GA on hypocotyl elongation.

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A Study of Gibberellin Homeostasis and Cryptochrome-Mediated Blue Light Inhibition of Hypocotyl Elongation

Cited by 149 publications

References 64 publications

Light Regulation of Gibberellin Biosynthesis in Pea Is Mediated through the COP1/HY5 Pathway

Light Regulation of Gibberellin Biosynthesis in Pea Is Mediated through the COP1/HY5 Pathway

Nitrate or NaCl regulates floral induction in Arabidopsis thaliana

Gibberellin Metabolism, Perception and Signaling Pathways in Arabidopsis

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