Project description:To understand mRNA expression pattern during cold acclimation and deacclimation, transcriptional profiling of cold acclimation and deacclimation-treated plants were analyzed using Agilent-015059 Arabidopsis 3 Oligo Microarray 4x44K G2519F.
Project description:To understand mRNA expression pattern during cold acclimation and deacclimation, transcriptional profiling of cold acclimation and deacclimation-treated plants were analyzed using Agilent-015059 Arabidopsis 3 Oligo Microarray 4x44K G2519F. Arabidopsis Col-0 were grown on MS plate for 2 weeks (16 hours light / 8 hours dark). Two week-old Arabidopsis samples (NA, non acclimation) were treated with cold (2 M-BM-:C) for 7 days (CA7d) under 12h/12h light/dark conditions. Deacclimation-treated samples (DA6h, DA12h, DA24h) were grown at normal growth temperature under long day conditions after cold treatment for 7 days. Then total RNA was prepared from the whole seedling and used for the microarray hybridization. Three replicative hybridization experiments for each array were carried out using the independent biological samples.
Project description:Abscisic acid (ABA) plays crucial regulatory roles in cold acclimation and deacclimation of grapevine, making it a potential tool to be utilized in vineyards for the acquisition of preferred phenotypes in winter and spring. To understand the function of ABA , we conducted two experiments during cold acclimation and deacclimation and evaluated the impact of exogenous abscisic acid (ABA) on the grapevine transcriptome. RNA-seq data were collected periodically hours or days after ABA treatment. Transcriptomic data were analyzed using principal component analysis (PCA) , hierarchical clustering, unsupervised weighed gene co-expression network analysis (WGCNA), contrast-based differentially expressed genes (DEGs) identification and pre-ranked gene set enrichment analysis (GSEA). Our results suggest that ABA functions differently during cold acclimation and deacclimation by selectively regulating key pathways including auxin/indole acetic acid (IAA) metabolism, galactose metabolism and ribosome biogenesis. We also identified the activation of several apparent negative feedback systems that regulated ABA-induced transcriptomic changes, suggesting the existence of a balancing system in response to excessive ABA.
Project description:Plants adapt to cold, non-freezing temperatures through cold acclimation and subsequently lose the acquired freezing tolerance in warmer temperatures in a process called deacclimation. By measuring the freezing tolerance of mutant lines, this study identified that the loss of HRA1, LBD41, MBF1c and JUB1 slows the rate of deacclimation in the first four days in Arabidopsis thaliana. Comparative transcriptomic (RNA-Seq) and co-expression analysis of Col-0, mbf1c and jub1 during deacclimation identified an involvement of thermoswitches, cell wall remodeler and transporters in the regulation of the rate of deacclimation. In mbf1c and jub1 a unique increase in stress responsive genes and regulation of the jasmonic acid pathway was detected and linked to the mutants’ retention of freezing tolerance during deacclimation. Hypoxia was observed to be induced in early deacclimation evidenced by an increase in ADH enzyme activity and upregulated gene expression of hypoxia markers (qRT-PCR). This work suggests that the overserved hypoxia response creates hypoxic niches within the plants and supports growth and development during deacclimation.
Project description:During low temperature exposure, temperate plant species increase their freezing tolerance in a process termed cold acclimation. During deacclimation in response to warm temperatures cold acclimated plants lose freezing tolerance and resume growth and development. While considerable effort has been directed toward understanding the molecular and metabolic basis of cold acclimation, much less information is available about the regulation of deacclimation. Here, we report metabolic (GC-MS) and transcriptional (microarrays, qRT-PCR) responses underlying deacclimation during the first 24 h after a shift of cold acclimated Arabidopsis thaliana (Columbia-0) plants to warm temperature. The data revealed a faster response of the transcriptome than of the metabolome and provided evidence for tightly regulated temporal responses at both levels. Metabolically deacclimation is associated with decreasing contents of sugars, amino acids and glycolytic and TCA cycle intermediates, indicating an increased need for carbon sources and respiratory energy production associated with growth resumption under warm temperature conditions. Deacclimation also involves extensive down-regulation of protein synthesis and changes in the metabolism of lipids and cell wall components. Altered hormonal regulation appears particularly important during deacclimation, with changes in the expression of genes related to auxin, gibberellin, brassinosteroid, jasmonate and ethylene metabolisms. Several transcription factor families controlling fundamental aspects of plant development are significantly regulated during deacclimation, emphasizing that loss of freezing tolerance and growth resumption are interrelated processes that are transcriptionally highly interrelated. Expression patterns of some clock oscillator components during deacclimation resembled those under warm conditions, indicating at least partial re-activation of the circadian clock. This study provide the first comprehensive analysis of the regulation of deacclimation in cold acclimated plants. The data indicate cascades of rapidly regulated genes and metabolites that underly the developmental switch resulting in reduced freezing tolerance and the resumption of growth. They constitute a reference dataset of genes, metabolites and pathways that are crucial during the first rapid phase of deacclimation and will be useful for the further analysis of this important but under-researched plant process. We used whole genome microarrays to monitor changes in gene expression in the Arabidopsis thaliana accession Columbia-0 during the first 24 h after a shift of cold acclimated plants to warm temperature.
Project description:In this study we used the Affymetrix Barley 1 GeneChip to investigate transcriptome responses of barley cv. Dicktoo to low temperature, including triplicated measurements of cold, freeze/thaw cycles and de-acclimation over 33 days. Experiment Overall Design: Plants were grown at 20ºC for seven days and subject to a symmetrical cycle of acclimation, cold, freeze-thaw, and deacclimation. Chilling began by decreasing the temperature overnight from 20ºC to 4ºC at a rate of 1.3ºC�h-1 and maintaining temperatures of 4 ºC in the day and 2ºC at night for 5 days. Freeze-thaw cycling lasted 12 days with day temperatures of 4ºC and night temperatures gradually decreasing from -2ºC the first night to -4ºC for three nights and -10ºC for four nights, then recovering to -4ºC for three nights and -2ºC for one night. This treatment was designed to allow daily freeze-thaw cycling and protein synthesis. Chilling conditions (4ºC day, 2ºC night) were resumed for five days, followed by deacclimation with increasing temperature to 20ºC overnight and maintaining for three days. Sampling was done at four different times, each at the 11th hour of light to avoid circadian effects: 1) before chilling treatment, 2) five days after initiation of chilling treatment, 3) eight days into freeze-thaw treatment and 4) three days into de-acclimation.
Project description:In this study we used the Affymetrix Barley 1 GeneChip to investigate transcriptome responses of barley cv. Morex to low temperature, including triplicated measurements of cold, freeze/thaw cycles and de-acclimation over 33 days. Experiment Overall Design: Plants were grown at 20ºC for seven days and subject to a symmetrical cycle of acclimation, cold, freeze-thaw, and deacclimation. Chilling began by decreasing the temperature overnight from 20ºC to 4ºC at a rate of 1.3ºCâ¢h-1 and maintaining temperatures of 4 ºC in the day and 2ºC at night for 5 days. Freeze-thaw cycling lasted 12 days with day temperatures of 4ºC and night temperatures gradually decreasing from -2ºC the first night to -4ºC for three nights and -10ºC for four nights, then recovering to -4ºC for three nights and -2ºC for one night. This treatment was designed to allow daily freeze-thaw cycling and protein synthesis. Chilling conditions (4ºC day, 2ºC night) were resumed for five days, followed by deacclimation with increasing temperature to 20ºC overnight and maintaining for three days. Sampling was done at four different times, each at the 11th hour of light to avoid circadian effects: 1) before chilling treatment, 2) five days after initiation of chilling treatment, 3) eight days into freeze-thaw treatment and 4) three days into de-acclimation.
Project description:The changes in the transcriptome of leaves between 0, 9, 13 and 17 days of cold acclimation were analyzed using RNA-Seq in Veyo and Falster genotypes of perennial ryegrass.
Project description:During cold acclimation plants increase their freezing tolerance in response to low non-freezing temperatures. This is accompanied by many physiological, biochemical and molecular changes that have been extensively investigated. In addition, many cold acclimated plants become more freezing tolerant during exposure to mild, non-damaging sub-zero temperatures. There is hardly any information available about the molecular basis of this adaptation. However, Arabidopsis thaliana is among the species that acclimate to sub-zero temperatures. This makes it possible to use the molecular and genetic tools available in this species to identify components of sub-zero signal transduction and acclimation. Here, we have used microarrays and a qRT-PCR primer platform covering 1880 genes encoding transcription factors to monitor changes in gene expression in the accessions Columbia-0, Rschew and Tenela during the first three days of sub-zero acclimation at -3°C. The results indicate that gene expression during sub-zero acclimation follows a tighly controlled time-course. Especially AP2/EREBP and WRKY transcription factors may be important regulators of sub-zero acclimation, although the CBF signal transduction pathway seems to be less important during sub-zero than during cold acclimation. Globally, we estimate that approximately 5% of all Arabidopsis genes are regulated during sub-zero acclimation. Particularly photosynthesis-related genes were down-regulated and genes belonging to the functional classes of cell wall biosynthesis, hormone metabolism and RNA regulation of transcription were up-regulated. Collectively, these data provide the first global analysis of gene expression during sub-zero acclimation and allow the identification of candidate genes for forward and reverse genetic studies into the molecular mechanisms of sub-zero acclimation. We used whole genome microarrays to monitor changes in gene expression in the Arabidopsis thaliana accessions Columbia-0, Rschew and Tenela during three days of acclimation to sub-zero temperature at -3°C after cold acclimation Plants from Arabidopsis thaliana accessions Columbia-0, Rschew and Tenela were cold acclimated at 4°C for two weeks. Detached leaves were then sub-zero acclimated at -3°C for 8 h, 1 d or 3 d at -3°C. Leaves of cold acclimated plants and sub-zero acclimated leaves were collected for RNA extraction and hybridization on Affymetrix ATH1 microarrays in order to explore temporal transcriptome changes during sub-zero acclimation. For each sample total RNA was isolated from a pool of three leaves from three different plants. The experiment was performed in three idenpendent biological replicates.
Project description:Dormant grapevine buds from 4 genotypes were collected over a variable time series after being exposed to growth room temperatures. Buds were collected from the field during winter and assessed for the loss of cold hardiness (deacclimation) in tandem with analysis of gene expression changes. DEGs are examined for various enriched pathways. Wild grapevines deacclimate faster than cultivated grapevines and the entire gene regulation cascade was also faster in wild grapevines. No keystone genes were identified that could explaint he faster phenotype, suggesting all the regulatory pathways are tuned faster in wild grapes.