Analysis of soybean DNA methylomes shows CHH hypermethylation enhances gene expression in cotyledons of developing seeds [mRNA]
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ABSTRACT: Cytosine methylation is an important mechanism for dynamical regulation of gene expression and transposon mobility during plant developmental processes. Recently, the variation of DNA methylation has been described between wild type and DNA methylation-related mutants in Arabidopsis thaliana. However, the elaborate representation of soybean DNA methylomes remains lacking. Here, we described the epigenome maps of soybean root, stem, leaf, and cotyledon of developing seed at a single-base resolution. We confirmed the transcription start sites of genes using high-throughput sequencing and reported the DNA methylation patterns in gene and transposon regions. The correlation between gene expression and DNA methylation was revealed through transcriptome sequencing. We found CHH methylation may function in promotion of gene expression and ten cotyledon-preferred genes were identified CHH hypermethylated in cotyledon. Small RNA library sequencing showed that DNA methylation was enhanced by small RNAs not by strand-specific way, and the variation of DNA methylation between the organs was highly related with expression of small RNAs.
Project description:Cytosine methylation is an important mechanism for dynamical regulation of gene expression and transposon mobility during plant developmental processes. Recently, the variation of DNA methylation has been described between wild type and DNA methylation-related mutants in Arabidopsis thaliana. However, the elaborate representation of soybean DNA methylomes remains lacking. Here, we described the epigenome maps of soybean root, stem, leaf, and cotyledon of developing seed at a single-base resolution. We confirmed the transcription start sites of genes using high-throughput sequencing and reported the DNA methylation patterns in gene and transposon regions. The correlation between gene expression and DNA methylation was revealed through transcriptome sequencing. We found CHH methylation may function in promotion of gene expression and ten cotyledon-preferred genes were identified CHH hypermethylated in cotyledon. Small RNA library sequencing showed that DNA methylation was enhanced by small RNAs not by strand-specific way, and the variation of DNA methylation between the organs was highly related with expression of small RNAs.
Project description:Cytosine methylation is an important mechanism for dynamical regulation of gene expression and transposon mobility during plant developmental processes. Recently, the variation of DNA methylation has been described between wild type and DNA methylation-related mutants in Arabidopsis thaliana. However, the elaborate representation of soybean DNA methylomes remains lacking. Here, we described the epigenome maps of soybean root, stem, leaf, and cotyledon of developing seed at a single-base resolution. We confirmed the transcription start sites of genes using high-throughput sequencing and reported the DNA methylation patterns in gene and transposon regions. The correlation between gene expression and DNA methylation was revealed through transcriptome sequencing. We found CHH methylation may function in promotion of gene expression and ten cotyledon-preferred genes were identified CHH hypermethylated in cotyledon. Small RNA library sequencing showed that DNA methylation was enhanced by small RNAs not by strand-specific way, and the variation of DNA methylation between the organs was highly related with expression of small RNAs.
Project description:Cytosine methylation is an important mechanism for dynamical regulation of gene expression and transposon mobility during plant developmental processes. Recently, the variation of DNA methylation has been described between wild type and DNA methylation-related mutants in Arabidopsis thaliana. However, the elaborate representation of soybean DNA methylomes remains lacking. Here, we described the epigenome maps of soybean root, stem, leaf, and cotyledon of developing seed at a single-base resolution. We confirmed the transcription start sites of genes using high-throughput sequencing and reported the DNA methylation patterns in gene and transposon regions. The correlation between gene expression and DNA methylation was revealed through transcriptome sequencing. We found CHH methylation may function in promotion of gene expression and ten cotyledon-preferred genes were identified CHH hypermethylated in cotyledon. Small RNA library sequencing showed that DNA methylation was enhanced by small RNAs not by strand-specific way, and the variation of DNA methylation between the organs was highly related with expression of small RNAs. small RNA profiling of roots, stems, leaves, and cotyledons of developing seeds
Project description:Cytosine methylation is an important mechanism for dynamical regulation of gene expression and transposon mobility during plant developmental processes. Recently, the variation of DNA methylation has been described between wild type and DNA methylation-related mutants in Arabidopsis thaliana. However, the elaborate representation of soybean DNA methylomes remains lacking. Here, we described the epigenome maps of soybean root, stem, leaf, and cotyledon of developing seed at a single-base resolution. We confirmed the transcription start sites of genes using high-throughput sequencing and reported the DNA methylation patterns in gene and transposon regions. The correlation between gene expression and DNA methylation was revealed through transcriptome sequencing. We found CHH methylation may function in promotion of gene expression and ten cotyledon-preferred genes were identified CHH hypermethylated in cotyledon. Small RNA library sequencing showed that DNA methylation was enhanced by small RNAs not by strand-specific way, and the variation of DNA methylation between the organs was highly related with expression of small RNAs. methylomes of roots, stems, leaves, and cotyledons of developing seeds
Project description:Cytosine methylation is an important mechanism for dynamical regulation of gene expression and transposon mobility during plant developmental processes. Recently, the variation of DNA methylation has been described between wild type and DNA methylation-related mutants in Arabidopsis thaliana. However, the elaborate representation of soybean DNA methylomes remains lacking. Here, we described the epigenome maps of soybean root, stem, leaf, and cotyledon of developing seed at a single-base resolution. We confirmed the transcription start sites of genes using high-throughput sequencing and reported the DNA methylation patterns in gene and transposon regions. The correlation between gene expression and DNA methylation was revealed through transcriptome sequencing. We found CHH methylation may function in promotion of gene expression and ten cotyledon-preferred genes were identified CHH hypermethylated in cotyledon. Small RNA library sequencing showed that DNA methylation was enhanced by small RNAs not by strand-specific way, and the variation of DNA methylation between the organs was highly related with expression of small RNAs. mRNA-Seq of roots, stems, leaves, and cotyledons of developing seeds
Project description:DNA methylation is a chemical modification of DNA that can be faithfully inherited across generations in flowering plant genomes. Failure to properly maintain DNA methylation can lead to epigenetic variation and transposon reactivation. Plant genomes are dynamic, spanning large ranges in size and there is an interplay between the genome and epigenome in shaping one another. To understand the variation in genomic patterning of DNA methylation between species, we compared methylomes of numerous diverse angiosperm species. By examining these variations in a phylogenetic context it becomes clear that there is extensive variation in mechanisms that govern gene body DNA methylation, euchromatic silencing of transposons and repeats, as well as silencing of heterochromatic transposons. Extensive variation is observed at all cytosine sequence contexts (CG, CHG and CHH, where H = A, C, T), with the Brassicaceae showing reduced CHG methylation levels and also reduced or loss of CG gene-body methylation. The Poaceae are characterized by a lack or reduction of heterochromatic CHH methylation and enrichment of CHH methylation in genic regions. Reduced CHH methylation levels are found in clonally propagated species, suggesting that these methods of propagation may alter the epigenomic landscape over time, in the absence of sexual reproduction. These results show that DNA methylation targeting pathways have diverged functionally and that extant DNA methylation patterns are likely a reflection of the evolutionary and life histories of plant species. Bisulfite-seq of leaf tissue from plants representing diverse angiosperms. RNA-seq and small RNA-seq was performed on leaf tissue of a subset of the species.
Project description:Background The soybean (Glycine max) cotyledon is a specialized tissue whose main function is to serve as a nutrient reserve that supplies the needs of the young plant throughout seedling development. During this process the cotyledons experience a functional transition to a mainly photosynthetic tissue. To identify at the genetic level the specific active elements that participate in the natural transition of the cotyledon from storage to photosynthetic activity, we studied the transcript abundance profile at different time points using a new soybean oligonucleotide chip containing 19,200 probes (70-mer long). Results After normalization and statistical analysis we determined that 3,594 genes presented a statistically significant altered expression in relation to the imbibed seed in at least one of the time points defined for the study. Detailed analysis of this data identified individual, specific elements of the glyoxylate pathway that play a fundamental role during the functional transition of the cotyledon from nutrient storage to photosynthesis. The dynamics between glyoxysomes and peroxisomes is evident during these series of events. We also identified several other genes whose products could participate co-ordinately throughout the functional transition and the associated mechanisms of control and regulation and we described multiple unknown genetic elements that by association have the potential to make a major contribution to this biological process. Conclusions We demonstrate that the global transcript profile of the soybean cotyledon during seedling development is extremely active, highly regulated and dynamic. We defined the expression profiles of individual gene family members, enzymatic isoforms and protein subunits and classified them accordingly to their involvement in different functional activities relevant to seedling development and the cotyledonary functional transition in soybean, especially the ones associated with the glyoxylate cycle. Our data suggests that in the soybean cotyledon a very complex and synchronized system of control and regulation of several metabolic pathways is essential to carry out the necessary functions during this developmental process. Keywords: Time Course
Project description:DNA methylation is a chemical modification of DNA that can be faithfully inherited across generations in flowering plant genomes. Failure to properly maintain DNA methylation can lead to epigenetic variation and transposon reactivation. Plant genomes are dynamic, spanning large ranges in size and there is an interplay between the genome and epigenome in shaping one another. To understand the variation in genomic patterning of DNA methylation between species, we compared methylomes of numerous diverse angiosperm species. By examining these variations in a phylogenetic context it becomes clear that there is extensive variation in mechanisms that govern gene body DNA methylation, euchromatic silencing of transposons and repeats, as well as silencing of heterochromatic transposons. Extensive variation is observed at all cytosine sequence contexts (CG, CHG and CHH, where H = A, C, T), with the Brassicaceae showing reduced CHG methylation levels and also reduced or loss of CG gene-body methylation. The Poaceae are characterized by a lack or reduction of heterochromatic CHH methylation and enrichment of CHH methylation in genic regions. Reduced CHH methylation levels are found in clonally propagated species, suggesting that these methods of propagation may alter the epigenomic landscape over time, in the absence of sexual reproduction. These results show that DNA methylation targeting pathways have diverged functionally and that extant DNA methylation patterns are likely a reflection of the evolutionary and life histories of plant species.
Project description:Eukaryotic DNA methylation is found in silent transposable elements and active genes. Nucleosome remodelers of the DDM1/Lsh family are thought to be specifically required to maintain transposon methylation, but the reason for this is unknown. Here, we find that a chromatin gradient that extends from the most heterochromatic transposons to euchromatic genes determines the requirement of DDM1 for methylation maintenance in all sequence contexts. We also show that small RNA-directed DNA methylation (RdDM) is inhibited by heterochromatin and absolutely requires the nucleosome remodeler DRD1. DDM1 and RdDM independently mediate nearly all transposon methylation, which is catalyzed by the methyltransferases MET1 (CG), CMT3 (CHG), DRM2 (CHH) and CMT2 (CHH), and collaborate to repress transposition and regulate the methylation and expression of genes. Our results indicate that the Arabidopsis genome is defined by a heterochromatic continuum that governs the access of DNA methyltransferases and potentially all DNA binding proteins. Examination of DNA methylation, transcription and nucleosomes in Arabidopsis wild-type and/or ddm1, RdDM and DNA methylase mutants.
Project description:Eukaryotic DNA methylation is found in silent transposable elements and active genes. Nucleosome remodelers of the DDM1/Lsh family are thought to be specifically required to maintain transposon methylation, but the reason for this is unknown. Here, we find that a chromatin gradient that extends from the most heterochromatic transposons to euchromatic genes determines the requirement of DDM1 for methylation maintenance in all sequence contexts. We also show that small RNA-directed DNA methylation (RdDM) is inhibited by heterochromatin and absolutely requires the nucleosome remodeler DRD1. DDM1 and RdDM independently mediate nearly all transposon methylation, which is catalyzed by the methyltransferases MET1 (CG), CMT3 (CHG), DRM2 (CHH) and CMT2 (CHH), and collaborate to repress transposition and regulate the methylation and expression of genes. Our results indicate that the Arabidopsis genome is defined by a heterochromatic continuum that governs the access of DNA methyltransferases and potentially all DNA binding proteins.