Project description:We advance a three gene model of arsenate tolerance in rice based on testing root growth of 108 recombinant inbred lines (RILs) of the Bala x Azucena population. Marker genotype at 3 loci determined arsenate tolerance in 99% of RILs tested. Interestingly, plants must inherit 2, but any two alleles from the tolerant parent (Bala) to have the tolerant phenotype. Challenging the Affymetrix GeneChip Rice Genome array with Azucena and Bala RNA isolated from control and arsenate treated plants revealed 592 genes 2 fold-upregulated by arsenate and 696 downregulated. The array data was also used to identify which genes are expressed within the three target loci. We used microarrays to detail the gene expression at three locations in the rice genome termed AsTol6.1, AsTol6.2 and AsTol10 in response to 1ppm arsenate. The data was also used to study the global gene expression of the two varieties of rice, Azucena and Bala, in the presence of 1ppm arsenate. Keywords: Hydroponics, 0 and 1ppm sodium arsenate, Rice varieties Azucena and Bala
Project description:Studies have shown that Rice Salt Sensitive 1 (RSS1) is involved in stress response in rice plants. Primers were developed for amplification via Polymerase Chain Reaction (PCR) of a region that contained a simple sequence repeat (SSR) in RSS1. PCR was performed on 6 different varieties of Oryza sativa. PCR product was sequenced on an ABI 3730 capillary sequence machine. Sequence data was aligned to observe differences in SSR length between each rice variety.
Project description:Studies have shown that Respiratory Burst Oxidase Homolog B (RBOHB) are involved in stress response in rice plants. Primers were developed for amplification via Polymerase Chain Reaction (PCR) of a region that contained a simple sequence repeat (SSR) in RBOHB. PCR was performed on 6 different varieties of Oryza sativa. PCR product was sequenced on an ABI 3730 capillary sequence machine. Sequence data was aligned to observe differences in SSR length between each rice variety.
Project description:The aim of this study was to conduct global gene expression profiling and comparative analysis of two chilling tolerant rice varieties, Jumli Marshi and Sijung (spp. Japonica), during early chilling stress (24h, 10C). Leaf tissue from cv. Jumli Marshi and cv. Sijung plants grown under chilling stress conditions were harvested after 4 and 24 h. Control plants (0 h) were harvested at the beginning of the experiment, i.e., at mid-day. Three biological replicates were profiled for each time point and variety. In order to readily detect highly (saturated) as well as weakly (near background signal) expressed genes, scanning was done twice on the microarrays: at the PMT sensitivity level 100% (pmt100) and 10% (pmt10).
Project description:Changes in patterns of gene expression are believed to be responsible for the phenotypic differences within and between species. Although the evolutionary significance of functional mutations has been emphasized in rice domestication, little is known about the differences in gene regulation underlying the phenotypic diversification among rice varieties. MicroRNAs (miRNAs) are small regulatory RNAs that play crucial roles in regulating post-transcriptional gene expression. Here, we studied the variation in the expression of both miRNAs and mRNA transcripts in three indica and three japonica rice varieties using RNA sequencing (RNA-seq) to examine the miRNA regulatory effect on target gene expression in rice. In total, 71.0%, 9.2%, and 1.5% of the expressed mature miRNAs showed tissue, subspecies, and tissue-subspecies interaction-biased expression. Most of these differentially expressed miRNAs are evolutionarily weakly conserved. To examine the miRNA regulatory effect on global gene expression under endogenous conditions, we performed pair-wise correlation coefficient analyses on the expression levels of 240 mature miRNAs and 1178 messenger RNAs (mRNAs) both globally and for each specific miRNA-mRNA pair. We found that the deeply conserved miRNAs can significantly decrease the target mRNA abundance. In addition, a total of 109 miRNA-mRNA pairs were identified as significantly correlated pairs (Adjusted p<0.01). Of those, 41 pairs showed positive correlations, while 68 pairs showed negative correlations. Functional analysis elucidated that these mRNAs belonged to different biological pathways that could regulate the stress response, metabolic processes, and rice development. In conclusion, the joint interrogation of miRNA and mRNA expression profiles in this study proved useful for the study of the role of miRNA expression and regulation in the plant transcriptome.
Project description:A biological phenomenon in which hybrids exhibit superior phenotypes from its parental inbred lines known as heterosis, has been widely exploited in plant breeding and extensively used in crop improvement. Hybrid rice has immense potential to increase yield over other rice varieties and hence is crucial in meeting increasing demand of rice globally. Moreover, the molecular basis of heterosis is still not fully understood and hence it becomes imperative to unravel its genetic and molecular basis. In this context, RNA sequencing technology (RNA-Seq) was employed to sequence transcriptomes of two rice hybrids, Ajay and Rajalaxmi, their parental lines, CRMS31A (sterile line, based on WA-CMS) and CRMS32A (sterile line based on Kalinga-CMS) respectively along with the common restorer line of both hybrids, IR-42266-29-3R at two critical rice developmental stages viz., panicle initiation (PI) and grain filling (GF). Identification of differentially expressed genes (DEGs) at PI and GF stages will further pave the way for understanding heterosis. In addition, such kind of study would help in better understanding of heterosis mechanism and genes up-regulated and down-regulated during the critical stages of rice development for higher yield.
Project description:In this study, we used a cross-species network approach to uncover nitrogen (N)-regulated network modules conserved across a model and a crop species. By translating gene network knowledge from the data-rich model Arabidopsis (Arabidopsis thaliana, ecotype Columbia-0) to a crop, rice (Oryza sativa spp. japonica (Nipponbare)), we identified evolutionarily conserved N-regulatory modules as targets for translational studies to improve N use efficiency in transgenic plants.