Project description:Here we report genome-wide high resolution allele-specific maps of DNA methylation and histone H3 lysine 27 trimethylation (H3K27me3) in maize endosperm. To investigate the allele-specific DNA methylation pattern of maize endosperm on a genome-wide scale, we performed MethylC-seq for shoot, embryo, and endosperm tissue 12 d after pollination (DAP) of inbred B73, and the endosperm tissue 12 DAP of reciprocal crosses B73 Ã Mo17 (BM) and Mo17 Ã B73 (MB). We also performed additional RNA-seq for samples from 12-DAP and 10-DAP endosperm of both reciprocal crosses between inbreds B73 and Mo17
Project description:Rice is a very important food staple that feeds more than half the world's population. Two major Asian cultivated rice (Oryza sativa L.) subspecies, japonica and indica, show significant phenotypic variation in their stress responses. However, the molecular mechanisms underlying this phenotypic variation are still largely unknown. A common link among different stresses is that they produce an oxidative burst and result in an increase of reactive oxygen species (ROS). In this study, methyl viologen (MV) as a ROS agent was applied to investigate the rice oxidative stress response. We observed that 93-11 (indica) seedlings exhibited leaf senescence with severe lesions under MV treatment compared to Nipponbare (japonica). Whole-genome microarray experiments were conducted, and 1,062 probe sets were identified with gene expression level polymorphisms between the two rice cultivars in addition to differential expression under MV treatment, which were assigned as Core Intersectional Probesets (CIPs). These CIPs were analyzed by gene ontology (GO) and highlighted with enrichment GO terms related to toxin and oxidative stress responses as well as other responses. These GO term-enriched genes of the CIPs include glutathine S-transferases (GSTs), P450, plant defense genes, and secondary metabolism related genes such as chalcone synthase (CHS). Further insertion/deletion (InDel) and regulatory element analyses for these identified CIPs suggested that there may be some eQTL hotspots related to oxidative stress in the rice genome, such as GST genes encoded on chromosome 10. In addition, we identified a group of marker genes individuating the japonica and indica subspecies. In summary, we developed a new strategy combining biological experiments and data mining to study the possible molecular mechanism of phenotypic variation during oxidative stress between Nipponbare and 93-11. This study will aid in the analysis of the molecular basis of quantitative traits.
Project description:Endosperm is an essential seed tissue with a unique epigenetic landscape. During endosperm development, differential epigenetic regulation of the maternal and paternal genomes plays important roles in regulating gene expression, especially at imprinted genes. Profiling the endosperm epigenetic landscape on a genome-wide scale is challenging due to its small size, mode of development, and close association with maternal tissue. Here, we applied a low input chromatin profiling method, CUT&RUN (cleavage under targets and release using nuclease), to profile parental-specific chromatin modifications using low numbers of Arabidopsis endosperm nuclei. We demonstrate that CUT&RUN generates genome-wide H3K27me3 landscapes with high sensitivity, specificity and reproducibility using around 20,000 endosperm nuclei purified by flow cytometry and fluorescence-activated cell sorting. H3K27me3 peaks identified by CUT&RUN and previous ChIP (chromatin immunoprecipitation) approaches were largely overlapping, with some distinctions in heterochromatin. The versatility and simplicity of CUT&RUN makes it a viable alternative to ChIP, which requires greater amounts of starting material, and will enable the study of tissue or even cell-type specific epigenomes in Arabidopsis and other plant species.
Project description:High throughput Illumina sequencing of poly-A selected RNA from Arabidopsis Col and Ler reciprocal F1 hybrid embryo and endosperm tissue isolated at 6-7 days after pollination to identify imprinted genes.
Project description:The nuclear content of the plant endosperm is the result of the contribution two maternal genomes and a single paternal genome. This 2:1 dosage relationship provides a unique system for studying the additivity of gene expression levels in reciprocal hybrids. A combination of microarray profiling and allele-specific expression analysis was performed using RNA isolated from endosperm tissues of maize inbred lines B73 and Mo17 and their reciprocal hybrids at two developmental stages, 13 and 19 days after pollination. By assessing the relative levels of expression in the reciprocal hybrids it was possible to determine the prevalence of additive and non-additive expression patterns. While the majority of differentially expressed genes displayed additive expression patterns in the endosperm, approximately 10% of the genes displayed non-additive expression patterns including maternal-like, paternal-like, dominant high-parent, dominant low-parent and expression patterns outside the range of the inbreds. The frequency of hybrid expression patterns outside of the parental range in maize endosperm tissue is much higher than that observed for vegetative tissues. For a set of 90 genes allele-specific expression assays were employed to monitor allelic bias and regulatory variation. Eight of these genes exhibited evidence for maternally or paternally biased expression at multiple stages of endosperm development and are potential examples of differential imprinting. Collectively, our data indicate that parental effects on gene expression are much stronger in endosperm than in vegetative tissues, and that endosperm imprinting may be far more common than previously estimated. Experiment Overall Design: Gene expression levels were profiled in 19 day after pollination endosperm tissue from four maize genotypes; B73, Mo17, Mo17xB73 and B73xMo17.
Project description:The nuclear content of the plant endosperm is the result of the contribution two maternal genomes and a single paternal genome. This 2:1 dosage relationship provides a unique system for studying the additivity of gene expression levels in reciprocal hybrids. A combination of microarray profiling and allele-specific expression analysis was performed using RNA isolated from endosperm tissues of maize inbred lines B73 and Mo17 and their reciprocal hybrids at two developmental stages, 13 and 19 days after pollination. By assessing the relative levels of expression in the reciprocal hybrids it was possible to determine the prevalence of additive and non-additive expression patterns. While the majority of differentially expressed genes displayed additive expression patterns in the endosperm, approximately 10% of the genes displayed non-additive expression patterns including maternal-like, paternal-like, dominant high-parent, dominant low-parent and expression patterns outside the range of the inbreds. The frequency of hybrid expression patterns outside of the parental range in maize endosperm tissue is much higher than that observed for vegetative tissues. For a set of 90 genes allele-specific expression assays were employed to monitor allelic bias and regulatory variation. Eight of these genes exhibited evidence for maternally or paternally biased expression at multiple stages of endosperm development and are potential examples of differential imprinting. Collectively, our data indicate that parental effects on gene expression are much stronger in endosperm than in vegetative tissues, and that endosperm imprinting may be far more common than previously estimated. Keywords: genotype comparison
Project description:The nuclear content of the plant endosperm is the result of the contribution two maternal genomes and a single paternal genome. This 2:1 dosage relationship provides a unique system for studying the additivity of gene expression levels in reciprocal hybrids. A combination of microarray profiling and allele-specific expression analysis was performed using RNA isolated from endosperm tissues of maize inbred lines B73 and Mo17 and their reciprocal hybrids at two developmental stages, 13 and 19 days after pollination. By assessing the relative levels of expression in the reciprocal hybrids it was possible to determine the prevalence of additive and non-additive expression patterns. While the majority of differentially expressed genes displayed additive expression patterns in the endosperm, approximately 10% of the genes displayed non-additive expression patterns including maternal-like, paternal-like, dominant high-parent, dominant low-parent and expression patterns outside the range of the inbreds. The frequency of hybrid expression patterns outside of the parental range in maize endosperm tissue is much higher than that observed for vegetative tissues. For a set of 90 genes allele-specific expression assays were employed to monitor allelic bias and regulatory variation. Eight of these genes exhibited evidence for maternally or paternally biased expression at multiple stages of endosperm development and are potential examples of differential imprinting. Collectively, our data indicate that parental effects on gene expression are much stronger in endosperm than in vegetative tissues, and that endosperm imprinting may be far more common than previously estimated. Keywords: genotype comparison
Project description:The nuclear content of the plant endosperm is the result of the contribution two maternal genomes and a single paternal genome. This 2:1 dosage relationship provides a unique system for studying the additivity of gene expression levels in reciprocal hybrids. A combination of microarray profiling and allele-specific expression analysis was performed using RNA isolated from endosperm tissues of maize inbred lines B73 and Mo17 and their reciprocal hybrids at two developmental stages, 13 and 19 days after pollination. By assessing the relative levels of expression in the reciprocal hybrids it was possible to determine the prevalence of additive and non-additive expression patterns. While the majority of differentially expressed genes displayed additive expression patterns in the endosperm, approximately 10% of the genes displayed non-additive expression patterns including maternal-like, paternal-like, dominant high-parent, dominant low-parent and expression patterns outside the range of the inbreds. The frequency of hybrid expression patterns outside of the parental range in maize endosperm tissue is much higher than that observed for vegetative tissues. For a set of 90 genes allele-specific expression assays were employed to monitor allelic bias and regulatory variation. Eight of these genes exhibited evidence for maternally or paternally biased expression at multiple stages of endosperm development and are potential examples of differential imprinting. Collectively, our data indicate that parental effects on gene expression are much stronger in endosperm than in vegetative tissues, and that endosperm imprinting may be far more common than previously estimated. Experiment Overall Design: Affymetrix microarrays were used to perform expression profiling on 13 day after pollination endosperm tissue of four different genotypes; B73; Mo17, B73xMo17 and Mo17xB73. There are three biological replicates for each of the tissues. Each biological sample represents a pool containing 5 endosperms each, from 6 different ears.