Project description:Natural epigenetic variation provides a source for the generation of phenotypic diversity, but to understand its contribution to phenotypic diversity, its interaction with genetic variation requires further investigation. MethylC-seq from naturally-occurring Arabidopsis accessions
Project description:We investigated DNA methylation variation in Swedish Arabidopsis thaliana accessions. We found that methylation of transposable elements is temperature sensitive and associated with genetic polymorphism in both cis and trans, whereas gene body methylation is associated with genetic polymorphism in trans. Additionally, complementary RNA-Seq data for the Arabidopsis accessions were used to correlate methylation changes with gene expression across environments.
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:Natural variation within plant species is an important resource for discovery of genes controlling biological traits. Gene-expression profiling of natural variation is increasingly used to identify genes affecting a trait. Here, we explored variation among Arabidopsis thaliana accessions with respect to defense against Pseudomonas syringae pv. tomato DC3000 (Pst), with a focus on R-gene mediated resistance triggered by the Pst type III effector protein AvrRpt2. We explored variation at two phenotypic levels: growth of the bacteria and hypersensitive response (HR) measured by electrolyte leakage. Considerable variation among accessions was found at both phenotypic levels. The genetic variation among accessions affected both growth of Pst with (Pst avrRpt2) and without (Pst) the AvrRpt2 effector, with some variation being specific for the bacterial strains, and other variation affecting both strains in a similar manner. Variation in HR was not correlated with variation in bacterial growth. Additionally we examine variation in gene-expression profiles after mock- and Pst avrRpt2-inoculated plants, obtained using a dedicated microarray Gene-expression profiling at 6 h post inoculation identified clusters of genes from which expression levels are correlated with bacterial growth and electrolyte leakage. The expression levels of some of these clusters correlate with more than one phenotypic characteristic, such as growth of both Pst and Pst avrRpt2, whereas other clusters were correlated with just one biological parameter. Thus we demonstrate that variation in gene-expression profiles among Arabidopsis accessions is correlated with variation in phenotypic responses. Keywords: Comparisons of Arabidopsis thaliana accessions with respect to inoculation with Pseudomonas syringae pv tomato avrRpt2.
Project description:Here we investigate DNA methylation variation in Swedish Arabidopsis thaliana accessions, demonstrating that methylation of transposable elements is temperature sensitive and associated with genetic polymorphism in both cis and trans, whereas gene body methylation is highly correlated with climate of origin and associated with genetic polymorphism in trans that shows evidence of local adaptation. While genome-wide surveys of naturally occurring DNA methylation have been published previously, the degree of genetic control revealed here is unprecedented. Furthermore, the observation that DNA methylation is associated with climate, and is apparently adaptively important, is completely novel. Bisulfite sequencing of 152 Swedish Arabidobsis accessions grown at 10 C and 121 grown at 16 C
Project description:These data provide a basis for the detection of sequence based polymorphisms between the Col-1, Tsu-1, and Kas-1 accessions of Arabidopsis thaliana. The experimental data provides an initial characterization of differences among the accessions, as well as a means for improving gene expression studies with the filtering of SFP from arrays studies. Recent studies have documented remarkable genetic variation among Arabidopsis thaliana accessions collected from diverse habitats and across its geographical range. Of particular interest are accessions with putatively locally adapted phenotypes – i.e., accessions with attributes that are likely adaptive under the climatic or habitat conditions of their sites of origin. These genotypes are especially valuable as they may provide insight into the genetic basis of adaptive evolution as well as allow the discovery of genes of ecological importance. Therefore we studied the physiology, genome content and gene expression of two physiologically extreme accessions (Tsu-1 from a wet environment in Tsushima, Japan and Kas-1 from a dry environment in Kashmir, India). The gene expression studies were conducted under two levels of soil moisture and accompanied by physiological measurements to characterize early responses to soil moisture deficit. Genomic hybridization experiments identified 42,503 single feature polymorphisms (SFP) between accessions, providing an initial screen for putative SNPs, indels, or changes in gene content.
Project description:To examine the rice genome methylation landscape and assess its functional significance, we generated the first single-base resolution genome methylation maps for Oryza sativa ssp. japonica, indica and their wild relatives, Oryza rufipogon and Oryza nivara. The methylation level of rice genomes is four times higher than that of Arabidopsis. Methylation in the promoter and gene body regions have similar patterns and effects on gene expression as those in Arabidopsis but different from a previous study on rice chromosomes 4 and 10. Most interestingly, we discovered for the first time that methylation in gene transcriptional termination regions can significantly repress gene expression, and the effect is even stronger than promoter methylation, which opens a new direction in the study of epigenetic regulation of gene expressions. Through integrated analysis of genetic, methylome and expression variation between cultivated and wild rice, we found that the genetic factor reflected by DNA variations may be the major determinant for methylation patterns at the whole-genome level and that methylation variation can only account for limited expression variation of genes between cultivated and wild rice.
Project description:These data provide a basis for exploration of gene expression differences between physiologically diverse accessions of Arabidopsis thaliana. Recent studies have documented remarkable genetic variation among Arabidopsis thaliana accessions collected from diverse habitats and across its geographical range. Of particular interest are accessions with putatively locally adapted phenotypes – i.e., accessions with attributes that are likely adaptive under the climatic or habitat conditions of their sites of origin. These genotypes are especially valuable as they may provide insight into the genetic basis of adaptive evolution as well as allow the discovery of genes of ecological importance. Therefore we studied the physiology, genome content and gene expression of 18 physiologically diverse accessions. The gene expression studies were conducted under two levels of soil moisture and accompanied by physiological measurements to characterize early responses to soil moisture deficit.
Project description:Understanding the mechanism of cadmium (Cd) accumulation in plants is important to help reduce its potential toxicity to both plants and humans through dietary and environmental exposure. Here, we report on a study to uncover the genetic basis underlying natural variation in Cd accumulation in a world-wide collection of 349 wild collected Arabidopsis thaliana accessions. We identified a 4-fold variation (0.5 – 2 μg Cd g-1 dry weight) in leaf Cd accumulation when these accessions were grown in a controlled common garden. By combining genome-wide association mapping, linkage mapping in an experimental F2 population and transgenic complementation, we reveal that HMA3 is the sole major locus responsible for the variation in leaf Cd accumulation we observe in this diverse population of A. thaliana accessions. Analysis of the predicted amino acid sequence of HMA3 from 149 A. thaliana accessions reveals the existence of 10 major natural protein haplotypes. Association of these haplotypes with leaf Cd accumulation and genetics complementation experiments indicate that 5 of these haplotypes are active and 5 are inactive, and that elevated leaf Cd accumulation is associated with the reduced function of HMA3 caused by a nonsense mutation and polymorphisms that change two specific amino acids.
Project description:Many environmental, genetic, and epigenetic factors are known to affect the frequency and positioning of meiotic crossovers (COs). Suppression of COs by large, cytologically visible inversions and translocations has long been recognized, but relatively little is known about how smaller structural variants (SVs) affect COs. To examine fine-scale determinants of the CO landscape, including SVs, we used a rapid, cost-effective method for high-throughput sequencing to generate a precise map of over 17,000 COs between the Col-0 and Ler accessions of Arabidopsis thaliana. COs were generally suppressed in regions with SVs, but this effect did not depend on the size of the variant region, and was only marginally affected by the variant type. CO suppression did not extend far beyond the SV borders, and CO rates were slightly elevated in the flanking regions. Disease resistance gene clusters, which often exist as SVs, exhibited high CO rates at some loci, but there was a tendency toward depressed CO rates at loci where large structural differences exist between the two parents. Our high-density map also revealed in fine detail how CO positioning relates to genetic (DNA motifs) and epigenetic (chromatin structure) features of the genome. We conclude that suppression of COs occurs over a narrow region spanning large and small-scale SVs, representing influence on the CO landscape in addition to sequence and epigenetic variation along chromosomes.