Genetic Regulation of Development in Sorghum bicolor (IX. The ma3R Allele Disrupts Diurnal Control of Gibberellin Biosynthesis)

Foster, Kenneth R.; Morgan, Page W.

doi:10.1104/pp.108.1.337

Cited by 52 publications

(41 citation statements)

References 19 publications

(31 reference statements)

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“…In potato (Solanum tuberosum), the complex diurnal profiles of StGA20ox1 and StGA20ox2 expression (Carrera et al, 1999;Jackson et al, 2000) suggest the involvement of circadian regulation. In line with the observed activity changes of GA-biosynthetic genes, the accumulation of bioactive GAs was also found to follow diurnal rhythmicity (Foster and Morgan, 1995). In addition to the daily oscillation of GA levels, the accumulation of elongationcontrolling indole-3-acetic acid and ethylene were shown to be determined by the circadian clock (Jouve et al, 1999;Thain et al, 2004).…”

Section: Discussionsupporting

confidence: 55%

Diurnal Regulation of the Brassinosteroid-Biosynthetic CPD Gene in Arabidopsis

et al. 2006

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Plant steroid hormones, brassinosteroids (BRs), are essential for normal photomorphogenesis. However, the mechanism by which light controls physiological functions via BRs is not well understood. Using transgenic plants carrying promoter-luciferase reporter gene fusions, we show that in Arabidopsis (Arabidopsis thaliana) the BR-biosynthetic CPD and CYP85A2 genes are under diurnal regulation. The complex diurnal expression profile of CPD is determined by dual, light-dependent, and circadian control. The severely decreased expression level of CPD in phytochrome-deficient background and the red light-specific induction in wildtype plants suggest that light regulation of CPD is primarily mediated by phytochrome signaling. The diurnal rhythmicity of CPD expression is maintained in brassinosteroid insensitive 1 transgenic seedlings, indicating that its transcriptional control is independent of hormonal feedback regulation. Diurnal changes in the expression of CPD and CYP85A2 are accompanied by changes of the endogenous BR content during the day, leading to brassinolide accumulation at the middle of the light phase. We also show that CPD expression is repressed in extended darkness in a BR feedback-dependent manner. In the dark the level of the bioactive hormone did not increase; therefore, our data strongly suggest that light also influences the sensitivity of plants to BRs.

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Section: Discussionsupporting

confidence: 55%

Diurnal Regulation of the Brassinosteroid-Biosynthetic CPD Gene in Arabidopsis

et al. 2006

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“…Levels of four of these GAs have been shown to cycle in a diurnal fashion in cv 90M (recessive phyB-2), cv 100M (dominant PHYB), and cv 58M (null mutant phyB-1). Furthermore, the timing of the peaks of bioactive GA 1 and its precursor GA 20 are shifted in the PhyB mutant, from afternoon in the wild type to early morning in the mutant (Foster and Morgan, 1995). The significance of these findings is enhanced by the observation that, when the mutant is grown under long, noninductive days, flowering is delayed and the GA 1 and GA 20 peaks shift to late in the day, similar to the timing observed for the wild type.…”

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confidence: 51%

Phytochrome B and the Regulation of Circadian Ethylene Production in Sorghum1

1998

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The sorghum (Sorghum bicolor L. Moench) cultivar 58M, which contains the null mutant phytochrome B gene, shows reduced photoperiodic sensitivity and exhibits a shade-avoidance phenotype. Ethylene production by seedlings of wild-type and phytochrome B mutant cultivars was monitored every 3 h, and both cultivars were found to produce ethylene in a circadian rhythm, with peak production occurring during the day. The phytochrome B mutant produces rhythmic peaks of ethylene with approximately 10 times the amplitude of the wild-type counterpart with the same period and diurnal timing. The source of the mutant's additional ethylene is the shoot. The diurnal rhythm can be produced with either light or temperature cycles; however, both light and temperature cycles are required for circadian entrainment. The temperature signal overrides the light signal in the production of diurnal rhythms, because seedlings grown under thermoperiods reversed with the photoperiod produced ethylene peaks during the warm nights. To examine the effect of extreme shading on ethylene production, seedlings were grown under dim, far-red-enriched light. This treatment duplicated the phytochrome B mutant's shade-avoidance phenotype in the wild type and caused the wild type to produce ethylene peaks similar to those observed in the mutant. The results confirm that phytochrome B is not required for proper function of circadian timing, but it may be involved in modulating physiological rhythms driven by the biological clock oscillator.

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“…Because GI regulates light input to the circadian clock (Huq et al, 2000;Martin-Tryon et al, 2007;Oliverio et al, 2007) and functions within the clock oscillator (Park et al, 1999;Edwards et al, 2005;Locke et al, 2005;Gould et al, 2006), changes in its phase could also alter the phase of other clock-associated factors. Not all outputs are affected (CO and FT phases are unchanged), but phase changes in particular rhythms in response to Pfr reduction have been reported in sorghum (Sorghum bicolor; Foster and Morgan, 1995) and barley (Hordeum vulgare; Deitzer et al, 1982), so this phenomenon may not be specific to GI.…”

Section: Discussionmentioning

confidence: 99%

Acceleration of Flowering during Shade Avoidance in Arabidopsis Alters the Balance betweenFLOWERING LOCUS C-Mediated Repression and Photoperiodic Induction of Flowering

Wollenberg

Strasser²,

Cerdán³

et al. 2008

Plant Physiology

109

131

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The timing of the floral transition in Arabidopsis (Arabidopsis thaliana) is influenced by a number of environmental signals. Here, we have focused on acceleration of flowering in response to vegetative shade, a condition that is perceived as a decrease in the ratio of red to far-red radiation. We have investigated the contributions of several known flowering-time pathways to this acceleration. The vernalization pathway promotes flowering in response to extended cold via transcriptional repression of the floral inhibitor FLOWERING LOCUS C (FLC); we found that a low red to far-red ratio, unlike cold treatment, lessened the effects of FLC despite continued FLC expression. A low red to far-red ratio required the photoperiod-pathway genes GIGANTEA (GI) and CONSTANS (CO) to fully accelerate flowering in long days and did not promote flowering in short days. Together, these results suggest a model in which far-red enrichment can bypass FLC-mediated late flowering by shifting the balance between FLC-mediated repression and photoperiodic induction of flowering to favor the latter. The extent of this shift was dependent upon environmental parameters, such as the length of far-red exposure. At the molecular level, we found that far-red enrichment generated a phase delay in GI expression and enhanced CO expression and activity at both dawn and dusk. Finally, our analysis of the contribution of PHYTOCHROME AND FLOWERING TIME1 (PFT1) to shade-mediated rapid flowering has led us to suggest a new model for the involvement of PFT1 in light signaling.

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Genetic Regulation of Development in Sorghum bicolor (IX. The ma3R Allele Disrupts Diurnal Control of Gibberellin Biosynthesis)

Cited by 52 publications

References 19 publications

Diurnal Regulation of the Brassinosteroid-Biosynthetic CPD Gene in Arabidopsis

Diurnal Regulation of the Brassinosteroid-Biosynthetic CPD Gene in Arabidopsis

Phytochrome B and the Regulation of Circadian Ethylene Production in Sorghum1

Acceleration of Flowering during Shade Avoidance in Arabidopsis Alters the Balance betweenFLOWERING LOCUS C-Mediated Repression and Photoperiodic Induction of Flowering

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