Project description:In natural habitats, plants are often exposed to multiple stresses. Most studies, however, for plant abiotic stress responses analyzed those to individual stress but not combined stresses. In this report, we performed comparison analyses of gene expression to individual stresses, salt, osmotic and heat, and to a combination of these three stresses, which mimics arid conditions. We show here that the combined stress treatment induces unique gene expression pattern but not a simple reflection of the additive effects of individual stresses. First, the number of genes induced by combined stresses (150 mM NaCl, 200 mM mannitol and 35°C heat) was much smaller when compared to the sum of those induced by individual stress treatments, while the number of genes downregulated by multiple stresses was larger. A large number of genes induced by mannitol were not induced by multiple stresses, while those induced by salts were less affected in combined stress treatments. In addition, 125 genes, including13 for transcription factors, were found to be induced specifically by combined stress treatments. We report here that the plant response to a multi-stress environment represents an output of complex interactions between different stress aspects and signaling events of the various components of this environmental situation, and the determinative factor in this response is to avoid/minimize the antagonistic effects and to magnify the synergistic features of the imposed environmental challenges. Based on our results, we propose that genes that are highly induced by multiple treatments may be candidate for engineering stress tolerant crop plants. Wild-type plants of Arabidopsis thaliana were treated with three abiotic stresses, high salinity (150mM and 300mM), high osmotic pressure (200mM and 400mM mannitol) and heat (35°C), individually or simultaneously. Plants were treated with salt or mannitol for 16 hrs (first 1 hr and last 7 hrs are in light and other time in dark) or with heat for 4 hrs (in light) before sampling. There are three biologcal replicates.
Project description:Plant responses to abiotic stresses are accompanied by massive changes in transcriptome composition. To provide a comprehensive view of stress-induced changes in the Arabidopsis thaliana transcriptome, we have used whole-genome tiling arrays to analyze the effects of salt, osmotic, cold and heat stress as well as application of the hormone abscisic acid (ABA), an important mediator of stress responses.
Project description:Multiprotein bridging factor 1c MBF1c (At3g24500) is a stress-response transcription co-activator. To test the function of MBF1c, we over-expressed it in transgenic Arabidopsis plants using the 35S-CaMV promoter. T4 seeds form 3 independent lines were tested for their tolerance to biotic and abiotic stress conditions. Constitutive expression of MBF1c in Arabidopsis enhanced the tolerance of transgenic plants to bacterial infection, salinity, heat and osmotic stress. Moreover, the enhanced tolerance of transgenic plants to osmotic and heat stress was maintained even when these two stresses were combined. The expression of MBF1c in transgenic plants augmented the accumulation of a number of sugars and defense transcrtipts in response to heat stress. Transcriptome profiling and inhibitor studies suggest that MBF1c expression enhances the tolerance of transgenic plants to heat and osmotic stress by partially activating, or perturbing, the ethylene-response signal transduction pathway. MBF1 proteins could be used to enhance the tolerance of plants to different abiotic stresses. Suzuki et al., 2005 Plant Physiology, submitted. Experimenter name = Ron Mittler Experimenter phone = 1-775-784-1384 Experimenter fax = 1-775-784-1650 Experimenter department = Dept. of Biochemistry Experimenter institute = University of Nevada Experimenter address = MS200 Experimenter address = Reno Experimenter address = Nevada Experimenter zip/postal_code = 89557 Experimenter country = USA Keywords: genetic_modification_design; stimulus_or_stress_design
Project description:Nontargeted and targeted metabolomics measurements of abiotic stress responses in three-week-old Arabidopsis thaliana plants' rosette leaf tissue for Col-0 wild type plants and double/triple knockout mutants of aquaporins (pip2;1 pip2;2 and pip2;1 pip2;2 pip2;4) treated with drought, heat at different air humidities, or combined drought-heat stress at different air humidities. This experiment contains FT-ICR-MS measurements for 103 Arabidopsis thaliana rosette leaf samples covering three genotypes under six different environmental conditions. The three genotypes comprise the Col-0 wildtype and two loss-of-function mutants of aquaporins, a pip2;1 pip2;2 double mutant and a pip2;1 pip2;2 pip2;4 triple mutant (respective AGI locus identifiers: AT3G53420, AT2G37170, AT5G60660). The six conditions include control condition (well-watered, 22 °C, 70% relative air humidity), drought stress (one week without watering), heat stress without changing the absolute humidity of the ambient air (6 hours at 33 °C, 37% relative air humidity), heat stress with supplemented air humidity to maintain a constant vapor pressure deficit before and during the heat episode (6 hours at 33 °C, 84% relative air humidity), and the combinations of drought pretreatment with each of the two heat stress variants (one week of drought followed by 6 hours of heat stress). Samples from all conditions were harvested at the same time (within 15 min starting at 5 pm). For validation, GC-TOF-MS measurements were done for two genotypes (wildtype, double mutant) and two conditions (drought, control) on partially overlapping samples.
Project description:Identification of differentially expressed genes in Arabidopsis thaliana mutants in response to combined abiotic stress treatment through Microarray experiment.
Project description:Multiprotein bridging factor 1c MBF1c (At3g24500) is a stress-response transcription co-activator. To test the function of MBF1c, we over-expressed it in transgenic Arabidopsis plants using the 35S-CaMV promoter. T4 seeds form 3 independent lines were tested for their tolerance to biotic and abiotic stress conditions. Constitutive expression of MBF1c in Arabidopsis enhanced the tolerance of transgenic plants to bacterial infection, salinity, heat and osmotic stress. Moreover, the enhanced tolerance of transgenic plants to osmotic and heat stress was maintained even when these two stresses were combined. The expression of MBF1c in transgenic plants augmented the accumulation of a number of sugars and defense transcrtipts in response to heat stress. Transcriptome profiling and inhibitor studies suggest that MBF1c expression enhances the tolerance of transgenic plants to heat and osmotic stress by partially activating, or perturbing, the ethylene-response signal transduction pathway. MBF1 proteins could be used to enhance the tolerance of plants to different abiotic stresses. Suzuki et al., 2005 Plant Physiology, submitted. Experimenter name = Ron Mittler; Experimenter phone = 1-775-784-1384; Experimenter fax = 1-775-784-1650; Experimenter department = Dept. of Biochemistry; Experimenter institute = University of Nevada; Experimenter address = MS200; Experimenter address = Reno; Experimenter address = Nevada; Experimenter zip/postal_code = 89557; Experimenter country = USA Experiment Overall Design: 6 samples were used in this experiment
Project description:Environmental stresses such as drought, heat and salinity limit plant development and agricultural productivity. While individual stresses have been studied extensively, much less is known about the molecular interaction of responses to multiple stresses. To address this problem, we investigated molecular responses of Arabidopsis thaliana to single, double, and triple combinations of salt, osmotic, and heat stresses. A metabolite profiling analysis indicated the production of specific compatible solutes depending on the nature of the stress applied. We found that in combination with other stresses, heat has a dominant effect on global gene expression and metabolites level patterns. Treatments that include heat stress lead to strongly reduced transcription of genes coding for abundant photosynthetic proteins and proteins regulating the cell life cycle, while genes involved in protein degradation are upregulated. Under combined stress conditions, the plants shifted their metabolism to a survival state characterized by low productivity. Our work provides molecular evidence for the dangers for plant productivity and future world food security posed by heat waves resulting from global warming. We highlight candidate genes, many of which are functionally uncharacterized, for engineering plant abiotic stress tolerance.
Project description:Arabidopsis thaliana and Arabidopsis lyrata are two closely related Brassicaceae species, which are used as models for plant comparative biology. They differ by lifestyle, predominant mating strategy, ecological niches and genome organization. To identify heat stress induced genes, we performed RNA-sequencing of rosette leaves from mock-treated, heat-stressed and heat-stressed-recoved plants of both species.
Project description:Global warming and heat stress belong to the most critical environmental challenges to agriculture worldwide, causing severe losses of major crop yields. In present study we report that the endophytic bacterium Enterobacter sp. SA187 protects Arabidopsis thaliana to heat stress. To understand the mechanisms at molecular level we performed RNA-seq