Genetic Regulation of Development in Sorghum bicolor (X. Greatly Attenuated Photoperiod Sensitivity in a Phytochrome-Deficient Sorghum Possessing a Biological Clock but Lacking a Red Light-High Irradiance Response)

Childs, Kevin L.; Lu, Jia Ling; Mullet, John E.; Morgan, Page W.

doi:10.1104/pp.108.1.345

Cited by 27 publications

(26 citation statements)

References 30 publications

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“…Possibly, PhyB is not fundamentally involved with setting the oscillator but is involved in coupling the response between the oscillator and the rhythm. Other evidence supporting this hypothesis has been presented: although CAB expression levels were dissimilar between the wild type and the PHYB mutant, a circadian rhythm with similar timing persisted in both (Childs et al, 1995).…”

Section: Discussionmentioning

confidence: 64%

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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Section: Discussionmentioning

confidence: 64%

Phytochrome B and the Regulation of Circadian Ethylene Production in Sorghum1

1998

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“…Thus, the inhibitory effect of phyB on the floral initiation under both SD and LD is observed commonly in flowering plants irrespective of LD or SD plants (Halliday et al, 1994;Childs et al, 1995). Moreover, an extended dark period (8L/16D) or EOD-FR treatments under SD (10L/14D) conditions hastened floral initiation of the wild type, resulting in the same flowering time as of phyB mutants ( Figure 8C).…”

Section: Flowering Time Of Phytochrome Mutantsmentioning

confidence: 82%

Distinct and Cooperative Functions of Phytochromes A, B, and C in the Control of Deetiolation and Flowering in Rice

et al. 2005

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We have isolated phytochrome B (phyB) and phyC mutants from rice (Oryza sativa) and have produced all combinations of double mutants. Seedlings of phyB and phyB phyC mutants exhibited a partial loss of sensitivity to continuous red light (Rc) but still showed significant deetiolation responses. The responses to Rc were completely canceled in phyA phyB double mutants. These results indicate that phyA and phyB act in a highly redundant manner to control deetiolation under Rc. Under continuous far-red light (FRc), phyA mutants showed partially impaired deetiolation, and phyA phyC double mutants showed no significant residual phytochrome responses, indicating that not only phyA but also phyC is involved in the photoperception of FRc in rice. Interestingly, the phyB phyC double mutant displayed clear R/FR reversibility in the pulse irradiation experiments, indicating that both phyA and phyB can mediate the low-fluence response for gene expression. Rice is a short-day plant, and we found that mutation in either phyB or phyC caused moderate early flowering under the long-day photoperiod, while monogenic phyA mutation had little effect on the flowering time. The phyA mutation, however, in combination with phyB or phyC mutation caused dramatic early flowering.

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“…The Iv mutants of pea, which are deficient in phyB, retain normal VLFR for leaflet expansion and inhibition of stem elongation (Weiler et al 1995). The ma/ mutant of sorghum has been proposed to be a phyB mutant and retains a partial response to Re, which might be a VLFR (Childs et al 1995). Thus, phyB operates via LFR and there is no evidence for a role in VLFR or HIR.…”

Section: Phytochrome a Mediates Very Low Fluence Responses Under Contmentioning

confidence: 99%

Dual effect of phytochrome A on hypocotyl growth under continuous red light

Mazzella

Magliano

Casal

1997

Plant Cell & Environment

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Tbe role of pbytocbrome A in tbe control of bypocotyl growtb under continuous red ligbt (Re) was investigated using phyA and phyB mutants of Arabidopsis thaliana, wbicb lack pbytochrome A (pbyA) or pbytocbrome B (pbyB), respeetively, and transgenie seedlings of Nicotiana tabacum overexpressing Avena pbyA, compared to tbe corresponding wild type (WT). In WT seedlings of A. thaliana, hypocotyl growtb inhibition showed a biphasic response to the fluence rate of Re, with a brake at 10 /imol m s . At equal total fluence rate, hourly pulses of red light caused slightly more inhibition than Re. The response to very low fluences of eontinuous or pulsed red light was absent in the phyA and phyA phyB mutants and present in the phyB mutant. The second part of the response was steeper in the phyA mutant than in the WT but was absent in the phyB mutant. In WT tobacco the response to Re was biphasic. Overexpression of Avena phyA enhanced the response only at very low fluence rates of Re (< 10"^ ;UmoI m~^ s"'). In both species, the effect of hourly pulses of far-red light was similar to the maximum inhibition observed in the first phase of the response to Re. Using reciprocity failure (i.e. higher inhibition under continuous than pulsed light) as the operational criterion, a 'true' high-irradianee reaction occurred under continuous far-red light but not under Re or red plus far-red light mixtures. Native and overexpressed phyA are proposed to mediate very low fluence responses under Re. In WT A. thaliana, this effeet is eounteraeted by a negative action of phyA on phyB-mediated low-fluenee responses.

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Genetic Regulation of Development in Sorghum bicolor (X. Greatly Attenuated Photoperiod Sensitivity in a Phytochrome-Deficient Sorghum Possessing a Biological Clock but Lacking a Red Light-High Irradiance Response)

Cited by 27 publications

References 30 publications

Phytochrome B and the Regulation of Circadian Ethylene Production in Sorghum1

Phytochrome B and the Regulation of Circadian Ethylene Production in Sorghum1

Distinct and Cooperative Functions of Phytochromes A, B, and C in the Control of Deetiolation and Flowering in Rice

Dual effect of phytochrome A on hypocotyl growth under continuous red light

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