Transcription profiling of Arabidopsis wild type and hfr1/sics1 knock-out mutant seedlings exposed to low R/FR light
ABSTRACT: Aim of the experiment is the identification of genes differentially regulated in hfr1/sics1 seedlings relative to wild type after prolonged exposure to low R/FR. To this end, gene expression changes were analysed in Arabidopsis wild-type and hfr1/sics1 knock-out mutant seedlings exposed to low R/FR light. The experiment was designed to enable comparison between the different genotypes exposed or not exposed to low R/FR light.
Shade-intolerant plants perceive the reduction in the ratio of red light (R) to far-red light (FR) as a warning of competition with neighboring vegetation and display a suite of developmental responses known as shade avoidance. In recent years, major progress has been made in understanding the molecular mechanisms underlying shade avoidance. Despite this, little is known about the dynamics of this response and the cascade of molecular events leading to plant adaptation to a low-R/FR environment. ...[more]
Project description:Aim of the experiment is the identification of regulatory genes rapidly induced by low R/FR and still up-regulated after prolonged exposure to FR-rich light. To this end, gene expression changes were analysed in Arabidopsis thaliana seedlings after exposure to low R/FR light for a short and a long period of time. The experiment was designed to enable comparison between treated and untreated Arabidopsis seedlings.
Project description:Aim of the experiment is the identification of genes differentially regulated in phyA seedlings relative to wild type after prolonged exposure to low R/FR. To this end, gene expression changes were analysed in Arabidopsis wild-type and phyA knock-out mutant seedlings exposed to low R/FR light. The experiment was designed to enable comparison between the different genotypes exposed or not exposed to low R/FR light.
Project description:Aim of the experiment is the analysis of early and late molecular events in plant response to canopy shade. To this end, gene expression changes were analysed in Arabidopsis seedlings after exposure to low R/FR light for 4 hours and 1 day. The experiment was designed to enable comparison between treated and untreated Arabidopsis seedlings.
Project description:The purpose of this experiment was to identify genes responding differently to a 24 h low red to far red ratio (R:FR) treatment in plants grown at 16 and 22 degrees Experiment Overall Design: Microarrays were used as a gene discovery tool to identify genes showing differential regulation by low R:FR at 2 growth temperatures. Plants subject to a 24 h low R:FR light treatment were compared with control plants maintained in high R:FR. This experiment was carried out at two growth temperatures, 16oC and 22oC.
Project description:In dense plant stands, the ratio between red and far-red (R:FR) light declines and shade intolerant species will respond to this cue for future shade by inducing the shade avoidance syndrome (SAS), enabling them to outgrow their neighbours. Shade tolerant species from the forest understory are unable to outgrow neighbouring trees and will suppress SAS. Although the molecular mechanisms underlying SAS are well studied in various species, mechanisms of SAS-suppression in shade tolerant species have rarely been studied. We applied RNA sequencing on Geranium pyrenaicum and G. robertianum, two wild species with contrasting growth responses to low R:FR light. G. pyrenaicum strongly induces petiole elongation when exposed to low R:FR light, at any time of the photoperiod. Contrastingly, G. robertianum only induces this response early in the day, and suppresses petiole growth in low R:FR light at the end of the photoperiod, which results after 24 hours in a net difference with control treatments of zero. We compared expression patterns in the most apical (most responsive) part of the second petioles, in two-week-old Geranium plants (two leaf stage) after 2 and 11.5 hours of far-red light enrichment. This way, we identified a number of novel candidate regulators of shade avoidance, and differential phytochrome control of plant immunity genes in the two species. For de-novo assembly of the reference transcriptomes, we pooled petiole- and leaf lamina tissue exposed to normal white light (180 mol m-2 s-1 PAR, R:FR 1.8, ± 60 mol m-2 s-1 blue light), low R:FR light (0.2), blue-depleted light (± 4 mol m-2 s-1 blue) and green shade (50 mol m-2 s-1 PAR, R:FR 0.45, ± 13 mol m-2 s-1 blue) for 2, 11.5 and 24 hours. Libraries of these samples were normalized, Illumina sequenced, and together with sequences of non-normalized petiole samples of the expression analysis constructed into a reference transcriptome for each species, using the Trinity protocol. Transcripts were clustered into orthologue clusters using the ortho-MCL clustering technique. Non-normalized libraries of samples (control vs. low R:FR light, 2 and 11.5 hours after start of the treatment) were sequenced and aligned to the newly assembled transcriptomes. Read counts were summed per orthologue cluster before statistical analysis was proceeded.
Project description:Plants respond to changes in the red:far red ratio (R:FR) of incident light. A reduction in this ratio (increase in FR) results in the Shade Avoidance Response (SAR) with associated changes in gene expression. The Phyotchrome-Interacting Factors (PIFs) are bHLH transcription factors known to be involved in the SAR. An analysis of changes in gene expression in WT and quadruple pif1pif3pif4pif5 (pifq; Leivar et al., 2008 (PMID 19920208)) mutant seedlings in response to an increase in FR should identify primary targets of PIF signaling. We used microarrays to examine the SAR in WT (Columbia) and pifq mutant Arabidopsis seedlings. Arabidopsis WT and pifq mutant seeds were plated on GM medium without sucrose at room temperature. During this procedure, the seeds were routinely exposed to white light (WL) for a total of 1.5 hours after imbibition. Seeds were then stratified for 5 days at 4ºC in darkness, and then grown in WL (19 umol/m2/s, R/FR ratio of 6.48) for 2 days at 21°C (WL0 samples). Two-day-old WL-grown seedlings were then maintained in the same fluence rate of WL supplemented with far-red light (WL-FR, R/FR ratio of 0.006) for 1 (FR1), 3 (FR3) or 24 (FR24) hours before harvesting. Control seedlings were also maintained in parallel in the same fluence rate of WL for 24h (WL24) before harvesting. Three different biological replicates of each treatment were grown separately and extracted, processed, and analyzed independently.
Project description:Low R:FR signaling through phytochromes induces shade avoidance responses, including petiole elongation. Salicylic acid-mediated defense against pathogens is inhibited under these conditions. Using microarrays we studied the crosstalk between low R:FR and SA at the global gene expression level in Arabidopsis thaliana. Plants were exposed for 2 h. to the following treatments: high R/FR with mock spray, low R/FR with mock spray, high R/FR with SA spray, low R/FR with SA spray. Gene expression was determined in petioles.
Project description:Low reduced red:far-red ratio [R:FR] signaling through phytochromes induces shade avoidance responses, including petiole elongation. Jasmonic acid-mediated defense against herbivores and pathogens is inhibited under these conditions. Using microarrays we studied the crosstalk between low R:FR and JA at the global gene expression level in Arabidopsis thaliana. Plants were exposed for 2 h. to the following treatments: high R/FR with mock spray, low R/FR with mock spray, high R/FR with JA spray, low R/FR with JA spray. Gene expression was determined in petioles.
Project description:This experiment was a time course performed over 24 hours to look at the effects on gene expression of exposure to low red:far-red ratio light in Arabidopsis thaliana plants. In this way genes involved in the shade avoidance response might be identified. This experiment was designed for gene identification only and containes no replicates,genes identified were verified by quantitative PCR for publication.
Project description:Phytochrome Interacting Factor 5 plays an important role in adaptive responses of plants to shaded environment collectively called shade avoidance syndrome. PIF 5 belongs to the bHLH transcription factor family and regulated gene expression in a low R/FR dependent fashion. In this experiment we investigate PIF5-DNA-binding genome wide to generate a candidate list of genes, which are directly regulated by PIF5. ChIP-Seq sample of whole seedlings treated with low R/FR light