Project description:Nitrate is the major source of nitrogen available for many crop plants and is often the limiting factor for plant growth and agricultural productivity especially for maize. Many studies have been done identifying the transcriptome changes under low nitrate conditions. However, the microRNAs (miRNAs) varied under nitrate limiting conditions in maize has not been reported. MiRNAs play important roles in abiotic stress responses and nutrient deprivation. We used the microarray systems to detect miRNAs responding to the chronic nitrate limiting conditions in maize leaves and roots.
Project description:We report de novo genome assemblies, transcriptomes, annotations, and methylomes for the 26 maize inbreds that serve as the founders for the maize nested association mapping population. The data indicate that the number of pan-genes in maize exceeds 103,000 and that the ancient tetraploid character of maize continues to degrade by fractionation to the present day. Excellent contiguity over repeat arrays and complete annotation of centromeres further revealed the locations and internal structures of major cytological landmarks. We show that combining structural variation with SNPs can improve the power of quantitative mapping studies. Finally, we document variation at the level of DNA methylation, and demonstrate that unmethylated regions are enriched for cis-regulatory elements that correlate with known QTLs and changes in gene expression.
Project description:Epigenetic modification plays important roles in plant and animal development. DNA methylation can impact the transposable element (TE) silencing, gene imprinting and regulate gene expression.Through a genome-wide analysis, DNA methylation peaks were respectively characterized and mapped in maize embryo and endosperm genome. Distinct methylation level across maize embryo and endosperm was observed. The maize embryo genome contained more DNA methylation peaks than endosperm. However, the endosperm chloroplast genome contained more DNA methylation peaks to compare with the embryo chloroplast genome. DNA methylation regions were characterized and mapped in genome. More CG island (CGI) shore are methylated than CGI in maize suggested that DNA methylation level is not positively correlated with CpG density. The DNA methylation occurred more frequently in the promoter sequence and transcriptional termination region (TTR) than other regions of the genes. The result showed that 99% TEs we characterized are methylated in maize embryo, but some (34.8%) of them are not methylated in endosperm. Maize embryo and endosperm exhibit distinct pattern/level of methylation. The most differentially methylated two regions between embryo and endosperm are High CpG content promoters (HCPs) and high CpG content TTRs (HCTTRs). DNA methylation peaks distinction of mitochondria and chloroplast DNA were less than the nucleus DNA. Our results indicated that DNA methylation is associated with the gene silencing or gene activation in maize endosperm and embryo. Many genes involved in embryogenesis and seed development were found differentially methylated in embryo and endosperm. We found 17 endosperm-specific expressed imprinting genes were hypomethylated in endosperm and were hypermethylated in embryo. The expression of a maize DEMETER -like (DME-like) gene and MBD101 gene (MBD4 homolog) which direct bulk genome DNA demethylation were higher in endosperm than in embryo. These two genes may be associated with the distinct methylation level across maize embryo and endosperm.The methylomes of maize embryo and endosperm was obtained by MeDIP-seq method. The global mapping of maize embryo and endosperm methylation in this study broadened our knowledge of DNA methylation patterns in maize genome, and provided useful information for future studies on maize seed development and regulation of metabolic pathways in different seed tissues. Examination of DNA methylated modifications in 2 maize tissues.
Project description:Nitrate is the major source of nitrogen available for many crop plants and is often the limiting factor for plant growth and agricultural productivity especially for maize. Many studies have been done identifying the transcriptome changes under low nitrate conditions. However, the microRNAs (miRNAs) varied under nitrate limiting conditions in maize has not been reported. MiRNAs play important roles in abiotic stress responses and nutrient deprivation. Root is the organ that plants transport nitrate. we used the microarray systems to perform a genome-wide search to detect miRNAs responding to the chronic and transient nitrate limiting conditions in maize.
2011-09-01 | GSE31231 | GEO
Project description:Global studies of drought-tolerance on maize
Project description:The maize B chromosome is a non-essential chromosome and is not detrimental to plant development at low copy numbers. Nondisjunction of the maize B chromosome occurs at the second pollen mitosis. Maize lines containing B chromosomes are widely used in a variety of studies, such as gene dosage effect, centromere function and engineering of artificial chromosomes etc. An understanding of how the B chromosome affect gene expression is required for utilizing the B chromosome as tools for genetic studies and engineering. Therefore, we performed RNA-seq and small-RNA seq experiments on maize lines containing one through seven copies of B chromosomes to examine how gene expression responds to change of B copy numbers.