ABSTRACT: Transcription profiling by array of three Arabidopsis accessions under acclimation to sub-zero temperature at -3 degree Celsius after cold acclimation
Project description:Plants from temperate regions can be primed by exposure to low, non-freezing temperatures resulting in improved freezing tolerance. Whereas the molecular and metabolic basis of cold priming has been investigated in detail, hardly anything is known about memory of a previous cold event under warm conditions and a following low temperature triggering event. We show that three days of cold priming at 4°C, a seven-day lag phase at 20°C and a triggering treatment of 4°C improved the freezing tolerance of Arabidopsis Col-0 and other accessions compared to plants that were not primed before. Transcripts, metabolites and lipids as possible molecular determinants of this increase in freezing tolerance were investigated in Arabidopsis accessions Col-0 and N14 after priming, memory phase and triggering by Illumina-based RNA-Seq, GC-MS metabolite profiling and UPLC FT-MS-based lipidomics. Comparing primed and triggered with only triggered samples 93 and 128 unique differentially expressed genes could be identified in Col-0 and N14, together with three and six significantly changed lipids and one metabolite in N14. Possible functions of these candidates will be discussed. This work identified for the first time molecular and metabolic changes accompanying cold stress memory and triggering by a second cold stress.
Project description:The cold acclimation process is regulated by many factors like ambient temperature, day length, light intensity, or hormonal status. Experiments with plants grown under different light-quality conditions indicate that the plant response to cold is also a light-quality-dependent process. Here, the role of light quality in the cold response was studied in one-month-old Arabidopsis thaliana (Col‐0) plants exposed for one week to 4 °C at short‐day conditions under white (100 and 20 μmol m‐2s‐1), blue or red (20 μmol m‐2s‐1) light conditions. An upregulated expression of CBF1, an inhibition of photosynthesis, and an increase in membrane damage showed that blue light enhanced the effect of low temperature. Interestingly, cold-treated plants under blue and red light showed only limited freezing tolerance compared to white light cold-treated plants. Next, the specificity of the light quality signal in cold response was evaluated in Arabidopsis accessions originating from different and contrasting latitudes. In all but one Arabidopsis accessions, blue light increased the effect of cold on photosynthetic parameters and electrolyte leakage. This effect was not found for Ws-0, which lacks functional CRY2 protein, indicating its role in the cold response. Proteomics data confirmed significant differences between red and blue light treated plants at low temperature and showed that the cold response is highly accession specific. In general, blue light increased mainly the cold-stress related proteins and red light induced higher expression of chloroplast-related proteins, which correlated with higher photosynthetic parameters in red light cold-treated plants. Altogether, our data suggest that light modulates two distinct mechanisms during the cold treatment - red light driven cell function maintaining program and blue light activated specific cold response. The importance of mutual complementarity of these mechanisms was demonstrated by significantly higher freezing tolerance of cold-treated plants under white light.
Project description:Low temperature is one of the major abiotic stresses limiting rice growth and productivity, it is urgent to reveal the genetic and molecular mechanisms of plant responses to low temperature stress and to search for useful genetic resources for improving low-temperature tolerance. the 8 accessions from China Core Collection include 4 cold tolerance accessions, 3 sensitivity accessions and 1 intermediate type accession. We used microarrays to detail variation of the gene expression after cold treatment and screen more cold-response genes in rice.
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: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
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:Arabidopsis thaliana and Eutrema salsugineum show the ability to cold acclimate. However, the degree of freezing tolerance depends in both cases on the accession. To elucidate the transcriptional basis of this differencial freezing tolerance, we performed where we grew plants under control conditions (20°C/18°C day/night) or under cold conditions (additional 4°C for 2 weeks). Rosettes were harvested from non-acclimated and cold acclimated plants for RNA isolation. Expression patterns were compared between treatments, accessions and species.
Project description:To understand the role of Arabidopsis histone deacetylase HDA6 in plant cold acclimation, we have employed transcriptional profiling of the hda6 mutant and its parental line under cold and control conditions to identify genes differentially expressed in the hda6 mutant under cold and control conditions. Aligent’s Whole Arabidopsis Gene Expression Microarray (G2519F, V4, 4x44K) were used. Arabidopsis hda6 mutant axe1-5 and its parental line DR5 were grown in MS agar plates for 2 weeks (16 hours light / 8 hours dark). For cold treated sample, the plants were subjected for cold treatment at 2?C for 3 days (12 hours light / 12 hours dark). Then total RNA was prepared and used for the microarray hybridization. Three replicative hybridization experiments for each array were carried out using the independent biological samples.
Project description:Plants experience a wide array of environmental stimuli to form a memory of adversity. Histone modification plays roles in plant stress memory, of which the mechanisms of H3K4me3 of low temperature memory in plants are poorly understood although H3K4me3 is a key histone modification. Combined with phenotypic analysis, chip-seq, and transcriptome analyses were performed to investigate the potential H3K4me3 contributions for different phases of recurring cold stresses Arabidopsis plants. We then performed gene expression profiling analysis using data obtained from RNA-seq of different low temperature treatments.
Project description:N6-methyldeoxyadenosine (6mA) is a newly-discovered DNA modification that plays a role in regulating plant adaptation to abiotic stresses. However, the changes and molecular regulatory mechanisms of N6-methyldeoxyadenosine under cold stress in plants remain uncertain. Here, we found the global level of 6mA in both Arabidopsis and rice are raised after cold treatment. Genome-wide profiling of 6mA revealed that 6mA peaks are primarily distributed within gene body regions under both normal and low-temperature conditions. Additionally, genes that were up-methylated were enriched in various biological processes, while down-methylated genes did not exhibit any significant enrichment. Association analysis showed that 6mA was positively correlated with gene expression level and 6mA-containing genes displayed a significantly higher expression level than non-6mA-containing genes. Joint analysis of the 6mA methylome and transcriptome of Arabidopsis and rice revealed that the fluctuations in 6mA levels caused by exposure to cold did not correlate with the changes of transcript levels in response to low temperatures. Moreover, we found that 6mA modified orthologous genes exhibit high expression levels. However, upon cold treatment, only a small amount of differentially 6mA-methylated orthologous genes were shared between Arabidopsis and rice. In sum, this study profiled the changes of 6mA in response to cold temperature and has unlocked the potential of this DNA modification in regulating the expression of stress-related genes.