Project description:Arabidopsis thaliana circadian and light signaling mutants have long hypocotyls under light/dark cycles. In order to determine if aberrant hypocotyl growth is due to time of day specific miss-expression of growth associated transcripts we conducted time course microarray experiments in the lux-2, lhy and phyB-9 mutants. The mutants and their parental genotypes were grown on plates under either intermediate days (12 hours light and 12 hours dark) for lux-2, or short day (8 hrs of light and 16 hrs of dark) for lhy and phyB-9, for seven days and tissue was collected every four hours over one day.
Project description:Phytochromes mediate a profound developmental shift when dark-grown seedlings are exposed to light. Here we show that a subset of genes is up regulated in phytochrome B (phyB) mutants even before dark-grown seedlings are exposed to light. Most of these genes bear the RY cis motif, which is a binding site of the transcription factor ABSCISIC ACID INSENSITIVE 3 (ABI3), and the phyB mutation also enhanced ABI3 expression. These changes in transcriptome have physiological consequences as seedlings of the abi3 mutant showed enhanced responses to pulses of far-red light, while ABI3 overexpressers exhibited the opposite pattern. Seedlings of the wild type derived from seeds germinated in full darkness showed enhanced expression of genes bearing the RY cis motif and reduced responses to far-red light. We propose that, via changes in ABI3 expression, light, perceived mainly by phyB in the seed, generates a downstream trans-developmental phase signal that pre-conditions the seedling to its most likely environment. Experiment Overall Design: We analysed the transcriptome profile in dark grown seedlings of the WT, and phyA phyB photoreceptor mutants. All seedlings have the same treatment (3d grown in complete darkness). We have two samples for each genotype that represent two replicates in each case.
Project description:In this study we used genetic approaches and transcriptome profiling to unravel the complex interaction of different developmental pathways required for chloroplast development in plants. The recently described snowy cotyledon 3 (sco3) mutant as well as the Phytochrome B (phyb) mutant revealed, in the double mutant, a complex suppressive or additive genetically linked regulation of chloroplast development, flowering time and transcription regulation. Transcriptional profilling of mutants with aberrant chloroplast development: sco3, phyb and the double mutant sco3phyb.
Project description:The mRNA expression profiles of the wild type, phyB and phyAB mutants were analyzed with darkness or 1 hour red light treatment. Results provide insight into the role of red-light and phytochromes in gene expression.
Project description:Phytochrome B (phyB) is a plant photoreceptor that forms a membraneless organelle called a photobody. However, its constituents are not fully known. Here, we isolated phyB photobodies from Arabidopsis leaves using fluorescence-activated particle sorting and analyzed their components. We found that a photobody comprises ~1,500 phyB dimers along with other proteins that could be classified into two groups: The first includes proteins that directly interact with phyB and localize to the photobody when expressed in protoplasts, while the second includes proteins that interact with the first group proteins and require co-expression of a first-group protein to localize to the photobody. As an example of the second group, TOPLESS (TPL) interacts with PHOTOPERIODIC CONTROL OF HYPOCOTYL 1 (PCH1) and localizes to the photobody when co-expressed with PCH1. Mutations in TPL family members cause shortened hypocotyls under red light, demonstrating that the method identifies photobody components that regulate red light signaling. Together, our results support that phyB photobodies include not only phyB and its primary interacting proteins but also its secondary interacting proteins.
Project description:Plants regulate their time to flowering by gathering information from the environment. Photoperiod and temperature are among the most important environmental variables. Suboptimal, but not near-freezing, temperatures regulate flowering through the thermosensory pathway, which overlaps with the autonomous pathway. Here we show that ambient temperature regulates flowering by two genetically distinguishable pathways, one that requires TFL1 and another that requires ELF3. The delay in flowering time observed at lower temperatures was partially suppressed in single elf3 and tfl1 mutants, whereas double elf3 tfl1 mutants were insensitive to temperature. tfl1 mutations abolished the temperature response in cryptochrome mutants that are deficient in photoperiod perception, but not in phyB mutants that have a constitutive photoperiodic response. Contrary to tfl1, elf3 mutations were able to suppress the temperature response in phyB mutants, but not in cryptochrome mutants. The gene expression profile revealed that the tfl1 and elf3 effects are due to the activation of different sets of genes and identified CCA1 and SOC1/AGL20 as being important cross talk points. Finally, genome-wide gene expression analysis strongly suggests a general and complementary role for ELF3 and TFL1 in temperature signalling. Three genotypes, WT (Columbia), elf3-7 and tfl1-1 mutants. Three biological replicates for each condition (genotype X temperature combination). RNA prepared independently for each sample.
Project description:Plants regulate their time to flowering by gathering information from the environment. Photoperiod and temperature are among the most important environmental variables. Suboptimal, but not near-freezing, temperatures regulate flowering through the thermosensory pathway, which overlaps with the autonomous pathway. Here we show that ambient temperature regulates flowering by two genetically distinguishable pathways, one that requires TFL1 and another that requires ELF3. The delay in flowering time observed at lower temperatures was partially suppressed in single elf3 and tfl1 mutants, whereas double elf3 tfl1 mutants were insensitive to temperature. tfl1 mutations abolished the temperature response in cryptochrome mutants that are deficient in photoperiod perception, but not in phyB mutants that have a constitutive photoperiodic response. Contrary to tfl1, elf3 mutations were able to suppress the temperature response in phyB mutants, but not in cryptochrome mutants. The gene expression profile revealed that the tfl1 and elf3 effects are due to the activation of different sets of genes and identified CCA1 and SOC1/AGL20 as being important cross talk points. Finally, genome-wide gene expression analysis strongly suggests a general and complementary role for ELF3 and TFL1 in temperature signalling.
Project description:Phytochromes mediate a profound developmental shift when dark-grown seedlings are exposed to light. Here we show that a subset of genes is up regulated in phytochrome B (phyB) mutants even before dark-grown seedlings are exposed to light. Most of these genes bear the RY cis motif, which is a binding site of the transcription factor ABSCISIC ACID INSENSITIVE 3 (ABI3), and the phyB mutation also enhanced ABI3 expression. These changes in transcriptome have physiological consequences as seedlings of the abi3 mutant showed enhanced responses to pulses of far-red light, while ABI3 overexpressers exhibited the opposite pattern. Seedlings of the wild type derived from seeds germinated in full darkness showed enhanced expression of genes bearing the RY cis motif and reduced responses to far-red light. We propose that, via changes in ABI3 expression, light, perceived mainly by phyB in the seed, generates a downstream trans-developmental phase signal that pre-conditions the seedling to its most likely environment. , ,
Project description:Phytochrome B (phyB), one member of phytochrome family in rice, plays important roles in regulating a range of developmental processes, and stress responses. However, little information about the mechanism involved in phyB-mediated light signaling pathway has been reported in rice. Another, it has been well-known that microRNAs (miRNAs) perform important roles in plant development and stress responses. Thus it is intriguing to explore the role of miRNAs in phyB-mediated light signaling pathway in rice. In this study, comparative high-throughput sequencing and degradome analysis were adopted to identify candidate miRNAs and their targets that participate in phyB-mediated light signaling pathway. A total of 838 known miRNAs, 663 novel miRNAs and 1,957 target genes were identified from wild-type (WT) and phyB mutant. Among them, 135 miRNAs showed differential expression, suggesting that the expressions of these miRNAs are under the control of phyB. In addition, 32 out of the 135 differentially expressed miRNAs were detected to slice 70 genes in rice genome. Analysis of these target genes showed that members of various transcription factor families constitute the largest proportion, indicating miRNAs are probably involved in phyB-mediated light signaling pathway mainly via regulating the expression of transcription factors. This study presented a comprehensive expression analysis of miRNAs and their targets that might be involved in phyB-mediated light signaling pathway for the first time. The results provide new clues for functional characterization of miRNAs in phyB-mediated light signaling pathway, which would be helpful in comprehensively uncovering molecular mechanism of phytochrome-mediated photomorphogenesis and stress responses in plant.
Project description:VERNALIZATION INSENSITIVE 3-LIKE (VIL) proteins are PHD-finger proteins that recruit the repressor complex Polycomb Repressive Complex 2 (PRC2) to the promoters of flowering repressors to promote flowering. Here, we show that the tomato VIL gene CRAWLING ELEPHANT (CREL) promotes differentiation throughout plant development and affects the trimethylation of Histone H3 on lysine 27 (H3K27me3) at a subset of PRC2 targets across the genome. We identified the crel mutant in a screen for suppressors of the simple-leaf phenotype of entire (e), a mutant in the AUX/IAA gene ENTIRE/SlIAA9, which is involved in compound-leaf development in tomato. crel mutants have increased leaf complexity, and suppress the ectopic blade growth of e mutants. In addition, crel mutants are late flowering, and have delayed and aberrant stem, root and flower development. Consistent with a role for CREL in recruiting PRC2, the H3K27me3 modification is altered at a subset of PRC2 targets throughout the genome in crel mutants. Our results uncover a wide role for CREL in plant and organ differentiation in tomato and suggest that CREL is required for targeting PRC2 activity, and thus silencing, to a specific subset of polycomb targets.