Project description:We use nucleosome maps obtained by high-throughput sequencing to study sequence specificity of intrinsic histone-DNA interactions. In contrast with previous approaches, we employ an analogy between a classical one-dimensional fluid of finite-size particles in an arbitrary external potential and arrays of DNA-bound histone octamers. We derive an analytical solution to infer free energies of nucleosome formation directly from nucleosome occupancies measured in high-throughput experiments. The sequence-specific part of free energies is then captured by fitting them to a sum of energies assigned to individual nucleotide motifs. We have developed hierarchical models of increasing complexity and spatial resolution, establishing that nucleosome occupancies can be explained by systematic differences in mono- and dinucleotide content between nucleosomal and linker DNA sequences, with periodic dinucleotide distributions and longer sequence motifs playing a secondary role. Furthermore, similar sequence signatures are exhibited by control experiments in which genomic DNA is either sonicated or digested with micrococcal nuclease in the absence of nucleosomes, making it possible that current predictions based on highthroughput nucleosome positioning maps are biased by experimental artifacts. Included are raw (eland) and mapped (wig) reads. The mapped reads are provided in eland and wiggle formats, and the raw reads are included in the eland file. This series includes only Mnase control data. The sonicated control is part of this already published accession, as is a in vitro nucleosome map: http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE15188 We also studied data (in vitro and in vivo maps as well as a model) from http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE13622 and from: http://www.ncbi.nlm.nih.gov/sra/?term=SRA001023
Project description:High temperature during the grain-filling stage causes deleterious effects on storage material accumulation and grain quality. But it is still unclear how high temperature affects storage materials accumulation. In this study, we systemically analyzed the expression pattern of rice genes under high temperture during the grain-filling stage.
Project description:High temperature influences plant development and can reduce crop yields. We used the Agilent Barley Gene Expression Microarray to identify high temperature responsive genes in cereals. In temperate cereals, such as wheat and barley, high temperature results in rapid progression through reproductive development in long-days but inhibits early stages of reproductive development in short-days. We examined the transcriptome of barley plants grown at two different temperatures, 15°C or 25°C, in either long or short-days. Under these conditions early reproductive development was accelerated by high temperature in long-days but inhibited by high temperature in short-days. To control for the effect of temperature on vegetative growth, plants were sampled at the same stage of vegetative development (leaf emergence) in all treatments. Transcriptome analysis identified genes that show changed transcript levels in response to daylength (long versus short-days), genes that show changed transcript levels in response to temperature (15°C versus 25°C), and small groups of genes that show changed transcript levels only in response to specific combinations of daylength and temperature. For example, genes that are upregulated only under long-days and high temperature: conditions in which early reproductive development proceeds rapidly. The temperature responsive genes identified here offer potential candidates for developmental regulators controlling the developmental response of cereal crops to high temperatures.
Project description:Analysis of gene expression of mid log phase cultures of Escherichia coli Ancestor strain, and high temperature evolved lines 42-1, 42-2 and 42-3. Keywords: other
Project description:Purpose: Brassica. juncea is vulnerable to abiotic stresses at specific stages in its life cycle. However, till date no attempts have been made to elucidate the genome-wide changes in the transcriptome of B. juncea subjected to either high temperature or drought stress. Hence, to gain global insights into genes, transcription factors and kinases regulated by these stresses and to provide basic information on coding transcripts that are associated with traits of agronomic importance, we utilized a combinatorial approach of next generation sequencing and de novo assembly to discover B. juncea transcriptome associated with high temperature and drought. Results: We constructed and sequenced three transcriptome libraries namely Brassica control (BC), Brassica high temperature stress (BHS) and Brassica drought stress (BDS) from control, high temperature treated and drought treated seedlings of Brassica juncea. More than 180 million purity filtered reads were generated which were processed through quality parameters and high quality reads were assembled de-novo using SOAPde-novo assembler. A total of 77750 unique transcripts were identified out of which 69,245 (89%) were annotated with high confidence. We established a subset of 19110 transcripts, which were differentially regulated by either high temperature and/or drought stress. Furthermore, 886 and 2834 transcripts that code for transcription factors and kinases, respectively, were also identified. Investigation of identified transcription factors revealed that 92 responded to high temperature, 72 exhibited alterations in expression during drought stress, and 60 were commonly associated with both the stresses. Similarly, 217, 259 and 193 kinases were responsive to high temperature, drought or both stresses, respectively. Maximum number of up-regulated transcription factors in high temperature and drought stress belonged to heat shock factors (HSFs) and dehydration responsive element-binding (DREB) families respectively. We also identified 239 metabolic pathways, which were perturbed during high temperature and drought treatments. Analysis of gene ontologies associated with differentially regulated genes forecasted their involvement in diverse biological processes. Conclusions: Our study provides first comprehensive discovery of B. juncea transcriptome under high temperature and drought stress conditions. Transcriptome resources generated in this study will enhance our understanding on the molecular mechanisms involved in defining the response of B. juncea against two important abiotic stresses. Furthermore this information would benefit designing of efficient crop improvement strategies for tolerance against conditions of high temperature regimes and water scarcity.
Project description:ngs2015_05_high_temperature_root-high temp wt - characterize changes in root gene expression associated with plant growth at higher temperature - plants were grown at 21°C or 26°C, 16h light (90µE)/8h dark for 10 days before harveting roots.