scholarly journals EARLY FLOWERING 3 and Photoperiod Sensing in Brachypodium distachyon

2022 ◽  
Vol 12 ◽  
Author(s):  
Frédéric Bouché ◽  
Daniel P. Woods ◽  
Julie Linden ◽  
Weiya Li ◽  
Kevin S. Mayer ◽  
...  
Keyword(s):  
Clock Genes ◽  
Brachypodium Distachyon ◽  
Expression Patterns ◽  
Marker Gene ◽  
Red Light ◽  
Early Flowering ◽  
Day Length ◽  
Wild Type ◽  
Complex Protein ◽  
Short Days

The proper timing of flowering, which is key to maximize reproductive success and yield, relies in many plant species on the coordination between environmental cues and endogenous developmental programs. The perception of changes in day length is one of the most reliable cues of seasonal change, and this involves the interplay between the sensing of light signals and the circadian clock. Here, we describe a Brachypodium distachyon mutant allele of the evening complex protein EARLY FLOWERING 3 (ELF3). We show that the elf3 mutant flowers more rapidly than wild type plants in short days as well as under longer photoperiods but, in very long (20 h) days, flowering is equally rapid in elf3 and wild type. Furthermore, flowering in the elf3 mutant is still sensitive to vernalization, but not to ambient temperature changes. Molecular analyses revealed that the expression of a short-day marker gene is suppressed in elf3 grown in short days, and the expression patterns of clock genes and flowering time regulators are altered. We also explored the mechanisms of photoperiodic perception in temperate grasses by exposing B. distachyon plants grown under a 12 h photoperiod to a daily night break consisting of a mixture of red and far-red light. We showed that 2 h breaks are sufficient to accelerate flowering in B. distachyon under non-inductive photoperiods and that this acceleration of flowering is mediated by red light. Finally, we discuss advances and perspectives for research on the perception of photoperiod in temperate grasses.

The early-flowering mutant efs is involved in the autonomous promotion pathway of Arabidopsis thaliana

Development ◽  
1999 ◽  
Vol 126 (21) ◽  
pp. 4763-4770 ◽  
Author(s):  
W.J. Soppe ◽  
L. Bentsink ◽  
M. Koornneef
Keyword(s):  
Arabidopsis Thaliana ◽  
Flowering Time ◽  
Double Mutant ◽  
Plant Size ◽  
Early Flowering ◽  
Wild Type ◽  
Late Flowering ◽  
Long Day ◽  
Short Days ◽  
Transition To Flowering

The transition to flowering is a crucial moment in a plant's life cycle of which the mechanism has only been partly revealed. In a screen for early flowering, after mutagenesis of the late-flowering fwa mutant of Arabidopsis thaliana, the early flowering in short days (efs) mutant was identified. Under long-day light conditions, the recessive monogenic efs mutant flowers at the same time as wild type but, under short-day conditions, the mutant flowers much earlier. In addition to its early-flowering phenotype, efs has several pleiotropic effects such as a reduction in plant size, fertility and apical dominance. Double mutant analysis with several late-flowering mutants from the autonomous promotion (fca and fve) and the photoperiod promotion (co, fwa and gi) pathways of flowering showed that efs reduces the flowering time of all these mutants. However, efs is completely epistatic to fca and fve but additive to co, fwa and gi, indicating that EFS is an inhibitor of flowering specifically involved in the autonomous promotion pathway. A vernalisation treatment does not further reduce the flowering time of the efs mutant, suggesting that vernalisation promotes flowering through EFS. By comparing the length of the juvenile and adult phases of vegetative growth for wild-type, efs and the double mutant plants, it is apparent that efs mainly reduces the length of the adult phase.

scholarly journals PCH1 integrates circadian and light-signaling pathways to control photoperiod-responsive growth in Arabidopsis

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
He Huang ◽  
Chan Yul Yoo ◽  
Rebecca Bindbeutel ◽  
Jessica Goldsworthy ◽  
Allison Tielking ◽  
...  
Keyword(s):  
Light Exposure ◽  
Red Light ◽  
Constitutive Expression ◽  
Day Length ◽  
Light Signaling ◽  
Dependent Manner ◽  
Phytochrome B ◽  
Necessary And Sufficient ◽  
New Protein ◽  
Short Days

Plants react to seasonal change in day length through altering physiology and development. Factors that function to harmonize growth with photoperiod are poorly understood. Here we characterize a new protein that associates with both circadian clock and photoreceptor components, named PHOTOPERIODIC CONTROL OF HYPOCOTYL1 (PCH1). pch1 seedlings have overly elongated hypocotyls specifically under short days while constitutive expression of PCH1 shortens hypocotyls independent of day length. PCH1 peaks at dusk, binds phytochrome B (phyB) in a red light-dependent manner, and co-localizes with phyB into photobodies. PCH1 is necessary and sufficient to promote the biogenesis of large photobodies to maintain an active phyB pool after light exposure, potentiating red-light signaling and prolonging memory of prior illumination. Manipulating PCH1 alters PHYTOCHROME INTERACTING FACTOR 4 levels and regulates light-responsive gene expression. Thus, PCH1 is a new factor that regulates photoperiod-responsive growth by integrating the clock with light perception pathways through modulating daily phyB-signaling.

scholarly journals The expression of circadian clock genes in Daphnia magna diapause

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Anke Schwarzenberger ◽  
Luxi Chen ◽  
Linda C. Weiss
Keyword(s):  
Gene Expression ◽  
Circadian Clock ◽  
Daphnia Magna ◽  
Seasonal Changes ◽  
Clock Genes ◽  
Diapause Induction ◽  
Day Length ◽  
Circadian Clock Genes ◽  
Short Days ◽  
Gene Expression Levels

AbstractDiapause is a mechanism necessary for survival in arthropods. Often diapause induction and resurrection is light-dependent and therefore dependent on the photoperiod length and on the number of consecutive short-days. In many organisms, including the microcrustacean Daphnia magna, one functional entity with the capacity to measure seasonal changes in day-length is the circadian clock. There is a long-standing discussion that the circadian clock also controls photoperiod-induced diapause. We tested this hypothesis in D. magna, an organism which goes into a state of suspended animation with the shortening of the photoperiod. We measured gene expression of clock genes in diapause-destined embryos of D. magna in the initiation, resting and resurrection phases and checked it against gene expression levels of continuously developing embryos. We demonstrate that some genes of the clock are differentially expressed during diapause induction but not during its maintenance. Furthermore, the photoreceptor gene cry2 and the clock-associated gene brp are highly expressed during induction and early diapause, probably in order to produce excess mRNA to prepare for immediate resurrection. After resurrection, both types of embryos show a similar pattern of gene expression during development. Our study contributes significantly to the understanding of the molecular basis of diapause induction, maintenance and termination.

scholarly journals juvenile albino, a Virescent Mutant in Watermelon: Inheritance and Expression

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 803E-803
Author(s):  
X. Zhang ◽  
B.B. Rhodes ◽  
W.V. Baird ◽  
H.T. Skorupska ◽  
W.C. Bridges
Keyword(s):  
Red Light ◽  
Nuclear Gene ◽  
Chlorophyll Synthesis ◽  
Early Spring ◽  
Day Length ◽  
Spontaneous Mutant ◽  
Wild Type ◽  
Late Fall ◽  
Young Leaves ◽  
Virescent Mutant

juvenile albino (ja) is a spontaneous mutant, first observed in 1992. Hypocotyls, new young leaves, shoot tips, tendrils, and flowers on the main shoot of the ja mutant are all albino during early spring and late fall. The interior of the albino leaves gradually become green, while the margins remain albino. Fruit rind color of the mutant is variegated. Growth of the ja mutant is severely impaired in the early spring and late fall. However, the mutant grows almost normal in the summer, and produces fruits of almost normal size. Genetic analysis of F1, F2, and BC1 populations derived from the ja mutant showed that ja mutant is inherited as a single, recessive, nuclear gene. The segregation ratios in the F2 and BC1 progenies derived from the cross between the previously reported dg virescent mutant and the ja mutant indicated that both are inherited independently. Experiments with temperature (3–5C vs. 20–22C at night), day length (8 vs. 15 h), and red and/or far-red light (15 vs. 0 min) at the end of an 8-h day were performed to investigate the regulation of ja trait expression. Temperature and red/far-red light had no differential effect on mutant and wild-type plants. However, significantly increased fresh weight and chlorophyll content were observed in the ja mutant over the wild-type when grown under long-day conditions. In addition, chlorophyll synthesis or accumulation in the mutant is severely impaired under short-day conditions. To our knowledge, this is the only virescent mutant in Cucurbitaceae whose expression is regulated by day length.

The smad5 mutation somitabun blocks Bmp2b signaling during early dorsoventral patterning of the zebrafish embryo

Development ◽  
1999 ◽  
Vol 126 (10) ◽  
pp. 2149-2159 ◽  
Author(s):  
M. Hild ◽  
A. Dick ◽  
G.J. Rauch ◽  
A. Meier ◽  
T. Bouwmeester ◽  
...  
Keyword(s):  
Zebrafish Embryo ◽  
Expression Patterns ◽  
Marker Gene ◽  
Single Amino Acid ◽  
Dorsoventral Patterning ◽  
Wild Type ◽  
Cell Fates ◽  
Marker Gene Expression ◽  
Smad Proteins ◽  
Set Up

Signaling by members of the TGFbeta superfamily is thought to be transduced by Smad proteins. Here, we describe a zebrafish mutant in smad5, designated somitabun (sbn). The dominant maternal and zygotic effect of the sbntc24 mutation is caused by a change in a single amino acid in the L3 loop of Smad5 protein which transforms Smad5 into an antimorphic version, inhibiting wild-type Smad5 and related Smad proteins. sbn mutant embryos are strongly dorsalized, similarly to mutants in Bmp2b, its putative upstream signal. Double mutant analyses and RNA injection experiments show that sbn and bmp2b interact and that sbn acts downstream of Bmp2b signaling to mediate Bmp2b autoregulation during early dorsoventral (D-V) pattern formation. Comparison of early marker gene expression patterns, chimera analyses and rescue experiments involving temporally controlled misexpression of bmp or smad in mutant embryos reveal three phases of D-V patterning: an early sbn- and bmp2b-independent phase when a coarse initial D-V pattern is set up, an intermediate sbn- and bmp2b-dependent phase during which the putative morphogenetic Bmp2/4 gradient is established, and a later sbn-independent phase during gastrulation when the Bmp2/4 gradient is interpreted and cell fates are specified.

scholarly journals Fusion of the SRDX Motif to OsPIL11 or OsPIL16 Causes Rice Constitutively Photomorphogenic Phenotypes In Darkness

2021 ◽  
Author(s):  
Yaping Li ◽  
Fang Zhang ◽  
Chongke Zheng ◽  
Jinjun Zhou ◽  
Xiangxue Meng ◽  
...  
Keyword(s):  
Expression Patterns ◽  
Red Light ◽  
Sequencing Analysis ◽  
Transcriptional Activators ◽  
Wild Type ◽  
Chlorophyll Metabolism ◽  
Expression Levels ◽  
Pathway Enrichment ◽  
Expression Of Genes ◽  
Transgenic Lines

Abstract Dark-grown seedlings develop skotomorphogenically. Because of the development of rice direct seeding cultivation systems, there is an increasing need for clarifying the molecular mechanism underlying rice skotomorphogenic development. It has been reported that SRDX motif, LDLDLELRLGFA, was able to convert a transcriptional activator into a strong repressor. In the present study, to explore the functions of PILs in rice skotomorphogenesis, we generated OsPIL11-SRDX and OsPIL16-SRDX transgenic lines by fusing the SRDX transcriptional repressor motif to the C-terminal of two members of the phytochrome interacting factor-like (OsPIL) family in rice (OsPIL11 and OsPIL16). The OsPIL11-SRDX and OsPIL16-SRDX seedlings grown in darkness had constitutively photomorphogenic phenotypes with short coleoptiles and open leaf blades. The results of an RNA sequencing analysis revealed that the dark-grown OsPIL11-SRDX and OsPIL16-SRDX lines had gene expression patterns similar to those of wild-type seedlings grown under red light. Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses indicated that the expression levels of genes related to photosynthesis, photosynthesis–antenna proteins, and porphyrin and chlorophyll metabolism were up-regulated in the dark-grown OsPIL11-SRDX and OsPIL16-SRDX lines, whereas the expression of genes related to the auxin pathway was down-regulated. In contrast, the expression levels of these photosynthesis-related genes were down-regulated in dark-grown transgenic seedlings overexpressing OsPIL11 or OsPIL16, which had exaggerated skotomorphogenesis. Considered together, our data indicate that OsPIL11 and OsPIL16 primarily function as transcriptional activators, at least in regards to promoting skotomorphogenesis and repressing the expression of photosynthesis-related genes.

Postnatal growth rate and gonadal development in circadian tau mutant hamsters reared in constant dim red light

Reproduction ◽  
2000 ◽  
pp. 327-330 ◽  
Author(s):  
RJ Lucas ◽  
JA Stirland ◽  
YN Mohammad ◽  
AS Loudon
Keyword(s):  
Time Course ◽  
Red Light ◽  
Somatic Growth ◽  
Postnatal Growth ◽  
Gonadal Development ◽  
Testicular Development ◽  
Wild Type ◽  
Similar Time ◽  
Syrian Hamsters ◽  
Body Weights

The role of the circadian clock in the reproductive development of Syrian hamsters (Mesocricetus auratus was examined in wild type and circadian tau mutant hamsters reared from birth to 26 weeks of age under constant dim red light. Testis diameter and body weights were determined at weekly intervals in male hamsters from 4 weeks of age. In both genotypes, testicular development, subsequent regression and recrudescence exhibited a similar time course. The age at which animals displayed reproductive photosensitivity, as exhibited by testicular regression, was unrelated to circadian genotype (mean +/- SEM: 54 +/- 3 days for wild type and 59 +/- 5 days for tau mutants). In contrast, our studies revealed a significant impact of the mutation on somatic growth, such that tau mutants weighed 18% less than wild types at the end of the experiment. Our study reveals that the juvenile onset of reproductive photoperiodism in Syrian hamsters is not timed by the circadian system.

scholarly journals Analysis of maxillopedia Expression Pattern and Larval Cuticular Phenotype in Wild-Type and Mutant Tribolium

Genetics ◽  
2000 ◽  
Vol 155 (2) ◽  
pp. 721-731 ◽  
Author(s):  
Teresa D Shippy ◽  
Jianhua Guo ◽  
Susan J Brown ◽  
Richard W Beeman ◽  
Robin E Denell
Keyword(s):  
Rna Interference ◽  
Expression Pattern ◽  
Tribolium Castaneum ◽  
Expression Patterns ◽  
Ectopic Expression ◽  
Homeotic Gene ◽  
Wild Type ◽  
Double Stranded Rna ◽  
Similar Expression ◽  
Mutant Phenotypes

Abstract The Tribolium castaneum homeotic gene maxillopedia (mxp) is the ortholog of Drosophila proboscipedia (pb). Here we describe and classify available mxp alleles. Larvae lacking all mxp function die soon after hatching, exhibiting strong transformations of maxillary and labial palps to legs. Hypomorphic mxp alleles produce less severe transformations to leg. RNA interference with maxillopedia double-stranded RNA results in phenocopies of mxp mutant phenotypes ranging from partial to complete transformations. A number of gain-of-function (GOF) mxp alleles have been isolated based on transformations of adult antennae and/or legs toward palps. Finally, we have characterized the mxp expression pattern in wild-type and mutant embryos. In normal embryos, mxp is expressed in the maxillary and labial segments, whereas ectopic expression is observed in some GOF variants. Although mxp and Pb display very similar expression patterns, pb null embryos develop normally. The mxp mutant larval phenotype in Tribolium is consistent with the hypothesis that an ancestral pb-like gene had an embryonic function that was lost in the lineage leading to Drosophila.

INFLUENCE OF PHOTOPERIOD ON THYROTROPIN RELEASING HORMONE-INDUCED PROLACTIN RELEASE IN EWES

1983 ◽  
Vol 63 (1) ◽  
pp. 67-73 ◽  
Author(s):  
B. E. HOWLAND ◽  
D. SONYA ◽  
L. M. SANFORD ◽  
W. M. PALMER
Keyword(s):  
Thyrotropin Releasing Hormone ◽  
Day Length ◽  
Constant Light ◽  
Serum Prolactin ◽  
Prolactin Release ◽  
Blood Samples ◽  
Releasing Hormone ◽  
Before And After ◽  
Release Curve ◽  
Short Days

The influence of photoperiod on serum prolactin levels and prolactin release induced by thyrotropin releasing hormone (TRH) was determined in ewes maintained under the following lighting regimes: Room 1, lighting mimicked natural changes in photoperiod; Room 2, annual photoperiod changes condensed into 6 mo with short days in June; Room 3, same as Room 2 except photoperiod changed abruptly from 16.5 to 8.0 h on 21 Mar. and back to 16.5 h on 21 June; Room 4, constant light. Weekly blood samples were obtained from February to August. Additionally, blood samples were collected before and after treatment with 10 μg TRH on 19 May, 13 June, 27 June and 19 July. Prolactin levels were elevated in ewes exposed to long days or constant light. The mean of all pre-TRH samples was significantly correlated with stress-induced elevations in prolactin (highest pre-TRH value) (r = 0.72) and area under the TRH-induced release curve (r = 0.56). The prolactin release in response to TRH was greatest in ewes exposed to long days or constant light. Abrupt increase of day length elevated pretreatment prolactin levels (P < 0.01) and increased area under the response curve (P < 0.05). Key words: Photoperiod, TRH, prolactin, ewes

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