Project description:Copy number variations (CNVs) can create new genes, change gene dosage, reshape gene structures, and modify elements regulating gene expression. As with all types of genetic variation, CNVs may influence phenotypic variation and gene expression. CNVs are thus considered major sources of genetic variation. Little is known, however, about their contribution to genetic variation in rice. To detect CNVs, we used a set of NimbleGen whole-genome comparative genomic hybridization arrays containing 715,851 oligonucleotide probes with a median probe spacing of 500 bp. We compiled a high-resolution map of CNVs in the rice genome, showing 641 CNVs between the genomes of the rice cultivars ‘Nipponbare’ (from O. sativa ssp. japonica) and ‘Guang-lu-ai 4’ (from O. sativa ssp. indica). These CNVs contain some known genes. They are linked to variation among rice varieties, and are likely to contribute to subspecific characteristics.
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:Towards understanding gene expression variation among related rice lineages on a genome-wide scale, we sought to assess global gene expression in the heading-stage panicle using a whole genome oligonucleotide microarray designed to represent 36,926 annotated indica genes.
Project description:In this study, integrated transcriptomics, proteomics and metabolomics approaches were applied to investigate the molecular responses of O3 in the leaves of two-weeks old rice (cv. Nipponbare) seedlings exposed to 0.2 ppm O3 for a period of 24 h. Based on the morphological alteration of O3-exposed rice leaves, transcript profiling of rice genes was performed in leaves exposed for 1, 12 and 24 h using rice DNA microarray chip, proteomics and metabolomics. This systematic survey showed that O3 triggers a chain reaction of altered gene, protein and metabolite expressions involved in multiple cellular processes in rice. Also investigated were the molecular responses in the leaves of two-weeks old rice (cv. Nipponbare) seedlings under continuous light and pure air (as a positive control for ozone exposure experiments) for a period of 24 h. Transcript profiling of rice genes was performed in leaves exposed for 1, 12 and 24 h using rice DNA microarray chip, proteomics and metabolomics. This systematic survey showed that continuous light and growth for 24 h also triggers a chain reaction of altered gene expressions involved in multiple cellular processes in rice, but different from those against ozone, in general. Keywords: Ozone fumigation response
Project description:Towards understanding gene expression variation among related rice lineages on a genome-wide scale, we sought to assess global gene expression in the heading-stage panicle using a whole genome oligonucleotide microarray designed to represent 36,926 annotated indica genes. Using a loop-design, we interrogated gene expression patterns in six related rice lineages, including O. sativa (two Asian cultivars indica and japonica), O. nivara (Asian annual wild rice), O. rufipogon (Asian perennial wild rice) and O. glaberrima (African cultivated rice). Series_sample_order: Sample 1-12 Slide A; Sample 13-24 Slide B
Project description:Rice Xa21 resistance gene, which encodes a protein with predicted leucine-rich repeat (LRR), transmembrane, juxtamembrane, and intracellular kinase domains, conferred immunity to diverse strains of Xanthomonas oryzae pv. oryzae (Xoo). We generated Xa21 plant on TP309 background (Oryza Sativa Japonica). Systemic Acquired Resistance (SAR) in plants confers durable broad-spectrum resistance to pathogens and requires a phytohormone, salicylic acid (SA). Arabidopsis NPR1/NIM1 is a key regulator of the SAR response. Recently, we found that rice NPR1 homolog 1 (NH1) mediated enhanced resistance responses for Xoo (Chern et al., 2005b). We further investigated relating pathways in rice by identifying proteins that interact with NH1. One of them, constitutive over-expression of NH1 mediated negative regulator of resistance (NRR) gene caused enhanced susceptibility to Xoo , indicating that this gene product negatively affects to basal resistance response (Chern et al., 2005a). To dissect defense responses for rice bacterial blight pathogen, we planed microarray using two resistant mutant named with Xa21-TP309, NH1ox and one super-susceptible mutant (NRRox) before pathogen inoculation and one day post pathogen inoculation. Keywords: Biotic stress response
Project description:We designed an array based on the release 7 of Michigan State University (MSU) rice genome annotation database (http://rice.plantbiology.msu.edu). The array was used for investigating the expression divergence and regulation between two contrasting rice genotypes under high salinity stress.