Project description:This SuperSeries is composed of the following subset Series: GSE35057: Phytochrome Interacting Factor 4 and 5 regulate different set of genes in high and low red/far-red light GSE35059: ChIP-Seq analysis of Phytochrome Interacting Factor 5 DNA binding in low R/FR condition Refer to individual Series
Project description:Phytochromes are red/far red photosensors regulating numerous developmental programs in plants. Among them phytochrome A (phyA) is essential to enable seedling de-etiolation in continuous far-red (FR) light a condition mimicking the environment under a dense canopy. The ecological relevance of this response is demonstrated by the high mortality rate of phyA mutants germinating in deep vegetational shade. phyA signaling involves a direct interaction of the photoreceptor with members of the bHLH transcription factor family, PIF1 and PIF3 (Phytochrome Interacting Factor). Here we investigated the involvement of PIF4 and PIF5 in phyA signaling and found that they redundantly control de-etiolation in FR light. The pif4pif5 double mutant is hypersensitive to low fluence rates of FR light. This phenotype is dependent on FR light perception by phyA but does not rely on alterations of the phyA level. Our microarrays analysis shows that PIF4 and PIF5 are part of an inhibitory mechanism repressing the expression of some light-responsive genes in the dark and are also needed for full expression of several growth-related genes in the light. Unlike PIF1 and PIF3, PIF4 and PIF5 are not degraded in response to FR light indicating that they are light-regulated by a different mechanism. Our genetic analysis suggests that this is achieved through the sequestration of these PIFs by the closely related bHLH transcription factor HFR1 (long Hypocotyl in FR light). Experiment Overall Design: he pif4pif5 double mutant were compared to wild-type plants when kept in the dark or subjected to 1 or 24 hours of 0.5 or 5 µmol/m2/s far-red light respectively.
Project description:Phytochromes are red/far red photosensors regulating numerous developmental programs in plants. Among them phytochrome A (phyA) is essential to enable seedling de-etiolation in continuous far-red (FR) light a condition mimicking the environment under a dense canopy. The ecological relevance of this response is demonstrated by the high mortality rate of phyA mutants germinating in deep vegetational shade. phyA signaling involves a direct interaction of the photoreceptor with members of the bHLH transcription factor family, PIF1 and PIF3 (Phytochrome Interacting Factor). Here we investigated the involvement of PIF4 and PIF5 in phyA signaling and found that they redundantly control de-etiolation in FR light. The pif4pif5 double mutant is hypersensitive to low fluence rates of FR light. This phenotype is dependent on FR light perception by phyA but does not rely on alterations of the phyA level. Our microarrays analysis shows that PIF4 and PIF5 are part of an inhibitory mechanism repressing the expression of some light-responsive genes in the dark and are also needed for full expression of several growth-related genes in the light. Unlike PIF1 and PIF3, PIF4 and PIF5 are not degraded in response to FR light indicating that they are light-regulated by a different mechanism. Our genetic analysis suggests that this is achieved through the sequestration of these PIFs by the closely related bHLH transcription factor HFR1 (long Hypocotyl in FR light).
Project description:The absorption of visible light in aquatic environments has led to the common assumption that aquatic organisms sense and adapt to penetrative blue/green light wavelengths, but show little or no response to the more attenuated red/far-red wavelengths. Here we show that two marine diatom species, Phaeodactylum tricornutum and Thalassiosira pseudonana, possess a bona fide red/far-red light sensing phytochrome (DPH) that uses biliverdin as a chromophore and displays accentuated red-shifted absorbance peaks compared to other characterized plant and algal phytochromes. Exposure to both red and far-red light causes changes in gene expression in P. tricornutum and the responses to far-red light disappear in DPH knockout cells, demonstrating that P. tricornutum DPH mediates far-red light signaling. The identification of DPH genes in diverse diatom species widely distributed along the water column further emphasizes the ecological significance of far-red light sensing, raising questions about the sources of far-red light. Our analyses indicate that, although far-red wavelengths from sunlight are only detectable at the ocean surface, chlorophyll fluorescence and Raman scattering can generate red/far-red photons in deeper layers. This study opens up novel perspectives on phytochrome-mediated far-red light signaling in the ocean and on the light sensing and adaptive capabilities of marine phototrophs.
Project description:PIL5 is a key negative regulator of phytochrome mediated seed germination and PIL5 protein is degraded by red light irradiation through phytochrome. The microarray aimed to find various red light-regulated genes and PIL5-regulated genes in the imbibed seeds. Experiment Overall Design: Col-0 and pil5 seeds were irradiated by far-red light or far-red/red light and then, incubated in the dark for 12 hours. Total three biological replicates were used for the microarray.
Project description:Analysis of etiolated seedlings exposed for 1hr to red light. Phytochromes are red/far-red light receptors, palying important roles in photomorphogenesis. Results suggest that red light and phytochromes regulate a set of genes' expression in seedlings.
Project description:phytochrome B (phyB) acts as the red light photoreceptor and negatively regulates the growth-promoting factor PHYTOCHROME INTERACTING 4 (PIF4) through a direct physical interaction, which in turn changes the expression of a large number of genes. phyB-PIF4 module regulates a variety of biological and developmental processes in plants. In this study, we demonstrate that B-BOX PROTEIN 11 (BBX11) physically interacts with both phyB and PIF4. BBX11 negatively regulates PIF4 accumulation as well as its biochemical activity, consequently leading to the repression of PIF4-controlled genes' expression and promotion of photomorphogenesis in the prolonged red light. This study reveals a regulatory mechanism that mediates red light signal transduction and sheds a light on phyB-PIF4 module in promoting red light-dependent photomorphognenesis.
Project description:The red/far-red light photoreceptor phytochrome mediates photomorphological responses in plants. For light sensing and signaling, phytochromes need to associate with open-chain tetrapyrrole molecules as the chromophore. Biosynthesis of tetrapyrrole chromophores requires members of ferredoxin-dependent bilin reductases (FDBRs). There are two FDBRs in Physcomitrella patens, HY2 and PUBS. Knocking out both generates the phytochrome-deficient mutant. Datasets here provides the transcriptome profiling of Physcomitrella protonema grown in the dark and exposed to one hour red light. Wild type and the hy2 pubs double mutant were used to dissect the regulated genes of moss phytochromes. For details, please see PMID: .
Project description:Light and microRNAs (miRNAs) are key external and internal signals for plant development respectively. However the relationship between light signaling and miRNA biogenesis pathways remains unknown. Here we found that miRNA processer DCL1/HYL1 interacts with a basic helix–loop–helix (bHLH) transcription factor, phytochrome-interacting factor 4 (PIF4), which mediates the destabilization of DCL1 during dark-red light transition. PIF4 acts as a transcription factor for some miRNA genes and is necessary for the proper accumulation of miRNAs. DCL1/HYL1 and mature miRNAs play roles in the regulation of plant hypocotyl growth. These results uncovered a previously unknown crosstalk between miRNA biogenesis and red light signaling through the PIF4-dependent regulation of miRNA transcription and processing to affect red light-directed plant photomorhogenesis.