Project description:Identification of differentially expressed genes in Arabidopsis thaliana mutants in response to combined abiotic stress treatment through Microarray experiment.
Project description:Arabidopsis plants that have experienced stress from water withdrawal show an improved ability to tolerate subsequent exposures as a ‘memory’ from the previous stress. This physiological stress memory is associated with ‘transcriptional memory’ illustrated by a subset of dehydrations stress responding genes that produce significantly different transcript amounts during repeated dehydration stresses relative to their response in the first. Here we report the genome-wide representation of dehydration stress transcriptional memory genes in A. thaliana. We identify four novel transcription patterns in response to repeated dehydration stress treatments. The nature of the proteins encoded by genes from each type of memory-response pattern is analyzed and the consequences of the genes’ memory behavior are considered in the context of possible biological relevance. The memory behavior of genes co-regulated by the dehydration/ABA and other abiotic stress and hormone responding pathways suggested that the crosstalk at the transcriptional level between them was affected as well. The intensity and the nature of specific biochemical, membrane, chloroplast, and stress response-related interactions during multiple exposures to dehydration stress are different from the responses to a single dehydration stress. The results reveal additional, hitherto unknown, levels of complexity of the plants’ transcriptional behavior when adjusting and adapting to recurring water deficits.
Project description:Arabidopsis plants that have experienced stress from water withdrawal show an improved ability to tolerate subsequent exposures as a ‘memory’ from the previous stress. This physiological stress memory is associated with ‘transcriptional memory’ illustrated by a subset of dehydrations stress responding genes that produce significantly different transcript amounts during repeated dehydration stresses relative to their response in the first. Here we report the genome-wide representation of dehydration stress transcriptional memory genes in A. thaliana. We identify four novel transcription patterns in response to repeated dehydration stress treatments. The nature of the proteins encoded by genes from each type of memory-response pattern is analyzed and the consequences of the genes’ memory behavior are considered in the context of possible biological relevance. The memory behavior of genes co-regulated by the dehydration/ABA and other abiotic stress and hormone responding pathways suggested that the crosstalk at the transcriptional level between them was affected as well. The intensity and the nature of specific biochemical, membrane, chloroplast, and stress response-related interactions during multiple exposures to dehydration stress are different from the responses to a single dehydration stress. The results reveal additional, hitherto unknown, levels of complexity of the plants’ transcriptional behavior when adjusting and adapting to recurring water deficits. For each condition (water, S1, and S3) the transcriptome was sequenced for two replicates. The watered condition is considered the control.
Project description:Freshwater is a limited and dwindling global resource; therefore, efficient water use is required for food crops that have high water demands, such as rice, or for the production of sustainable energy biomass. We show here that expression of the Arabidopsis HARDY (HRD) gene in rice improves water use efficiency, the ratio of biomass produced to the water used, by enhancing photosynthetic assimilation and reducing transpiration. These drought tolerant low-water-consuming rice plants exhibit increased shoot biomass under well irrigated conditions and an adaptive increase in root biomass under drought stress. The HRD gene, an AP2/ERF-like transcription factor, identified by a gain-of-function Arabidopsis mutant hrd-D having roots with enhanced strength, branching, and cortical cells, exhibits drought resistance and salt tolerance, accompanied by an enhancement in the expression of abiotic stress associated genes. Although HRD overexpression in Arabidopsis produces thicker leaves with more chloroplast-bearing mesophyll cells, in rice there is an increase in leaf biomass and bundle sheath cells that probably contribute to the enhanced photosynthesis assimilation and efficiency. HRD overexpression was also studied for clues of molecular mechanisms involved using microarrays. The results exemplify application of a gene identified from the model plant Arabidopsis for the improvement of water use efficiency coincident with drought resistance in the crop plant rice. Keywords: Genetic modification transcription factor overexpression mutant