Project description:Arabidopsis Col-0 seeds were germinated and grown for two weeks on Arabidopsis thaliana salt media (ATS, control) or ATS media supplemented 50, 75, 100 or 125 mM NaCl that imposes both an ionic and osmotic stress; or ATS media supplemented with iso-osmolar concentrations of sorbitol (100, 150, 200 or 250 mM) that imposes only an osmotic stress. The aim of the study was to identify genes involved in plant growth and adaptation to ionic stress compared to genes involved in growth and adaptation to osmotic stress conditions. To do this we identified lists of genes that are differentially expressed in plants grown in NaCl (A) and lists of genes differentially expressed in plants grown in sorbitol (B). We then compared these lists to find ionic/salt-specific genes that are only expressed in plants grown in NaCl and not in plants grown in sorbitol; and osmotic genes that are expressed both in plants grown in NaCl and in plants grown in sorbitol. Associated publication: Cackett et al. (2022) Salt-specific gene expression reveals elevated auxin levels in Arabidopsis thaliana plants grown under saline conditions, DOI: 10.3389/fpls.2022.804716
Project description:Bacteria respond to osmotic stress by a substantial increase in the intracellular osmolality, adjusting their cell turgor for altered growth conditions. Using E. coli as a model organism we demonstrate here that bacterial responses to hyperosmotic stress specifically depend on the nature of osmoticum used. We show that increasing acute hyperosmotic NaCl stress above ~1.0 Os kg-1 causes a dose-dependent K+ leak from the cell, resulting in a substantial decrease in cytosolic K+ content and a concurrent accumulation of Na+ in the cell. At the same time, isotonic sucrose or mannitol treatment (non-ionic osmotica) results in a gradual increase of the net K+ uptake. Ion flux data is consistent with growth experiments showing that bacterial growth is impaired by NaCl at the concentration resulting in a switch from net K+ uptake to efflux. Microarray experiments reveal that about 40% of up-regulated genes shared no similarity in their responses to NaCl and sucrose treatment, further suggesting specificity of osmotic adjustment in E. coli to ionic- and non-ionic osmotica The observed differences are explained by the specificity of the stress-induced changes in the membrane potential of bacterial cells highlighting the importance of voltage-gated K+ transporters for bacterial adaptation to hyperosmotic stress.
Project description:Generally, salt stress causes both osmotic and ionic stress. To discern the effects of osmotic and ionic specific effects on Burma mangrove transcriptome, we conducted expression profiling in 500 mM NaCl or 1M solbitol treated leaves. This study will lead to a rapid and effective selection of gene that confers high salt tolerance in transgenic plants and to a comprehensive understanding of plant stress response. Keywords: Stress response
Project description:Bacteria respond to osmotic stress by a substantial increase in the intracellular osmolality, adjusting their cell turgor for altered growth conditions. Using E. coli as a model organism we demonstrate here that bacterial responses to hyperosmotic stress specifically depend on the nature of osmoticum used. We show that increasing acute hyperosmotic NaCl stress above ~1.0 Os kg-1 causes a dose-dependent K+ leak from the cell, resulting in a substantial decrease in cytosolic K+ content and a concurrent accumulation of Na+ in the cell. At the same time, isotonic sucrose or mannitol treatment (non-ionic osmotica) results in a gradual increase of the net K+ uptake. Ion flux data is consistent with growth experiments showing that bacterial growth is impaired by NaCl at the concentration resulting in a switch from net K+ uptake to efflux. Microarray experiments reveal that about 40% of up-regulated genes shared no similarity in their responses to NaCl and sucrose treatment, further suggesting specificity of osmotic adjustment in E. coli to ionic- and non-ionic osmotica The observed differences are explained by the specificity of the stress-induced changes in the membrane potential of bacterial cells highlighting the importance of voltage-gated K+ transporters for bacterial adaptation to hyperosmotic stress. Experiment Overall Design: Two biological replicates per treatment with microarray analysis using the Affymetrix GeneChip E. coli Genome array. Treatments used included: Experiment Overall Design: Control - E. coli Frag1, grown to early stationary growth phase in a mineral salts medium with 0.1% glucose at 25 C Experiment Overall Design: Sucrose hyperosmotic treatment - 1.25 M sucrose added to control culture Experiment Overall Design: for 10 min. Experiment Overall Design: NaCl hyperosmotic treatment - 1.37 M NaCl added to control culture Experiment Overall Design: For microarray data comparisons the sucrose and NaCl hyperosmotic treatment data was compared to the no treatment control data separately. The sucrose to control and NaCL to control comparison data tables are linked below.
Project description:Transcriptomic study of the impact of osmopriming on rape seeds (Brassica napus L.; cv 'Libomir') during priming process and after germination. The assays were replicated twice on two independent priming and germination experiments. Seeds were osmoprimed in PEG solution (-1.2 MPa osmotic potential) during 7 days, dried to initial moisture content and then germinated for 7 hours on water. The analysis during different phases of priming procedure (soaking and drying), after whole osmopriming process and germination were done.
Project description:We used RNA-Seq to measure transcript abundance in 4 Saccharomyces cerevisiae strains (BY4743, BC187, NCYC3290, and YPS128) from a diverse range of genetic lineages when growing in rich media (YPD) with 0.7M NaCl to characterize differential expression across strains in response to osmotic and ionic stress.
Project description:Salt and PEG tolerances of 70 Arabidopsis accessions were screened. Five commonly used Arabidopsis accessions (C24, Col, Ler, SHA, Ws) were selected for further analysis. The results showed that SHA and C24 were relatively tolerant, while Ler and Ws were relatively susceptible to both salt and PEG stress. Transcriptomic analysis revealed that 4105 to 8782 genes exhibited significant expression level changes among five accessions in the presence and absence of stress treatments. The function of these genes were involved in stress response, ROS and metabolic pathways. The detailed networks affected by salt and osmotic stresses were dissected.
Project description:Transcriptomic study of the impact of osmopriming on rape seeds (Brassica napus L.; cv 'Libomir') during priming process and after germination. The assays were replicated twice on two independent priming and germination experiments. Seeds were osmoprimed in PEG solution (-1.2 MPa osmotic potential) during 7 days, dried to initial moisture content and then germinated for 7 hours on water. The analysis during different phases of priming procedure (soaking and drying), after whole osmopriming process and germination were done. 10 samples, four condition experiment; non dried primed seeds (Pnd) vs. dry unprimed seeds (UPd) (PEG soaking), non dried primed seeds (Pnd) vs dry primed seeds (Pd) (drying after soaking), dry primed seeds (Pd) vs. dry unprimed seeds (UPd) (full osmopriming process), primed seeds imbibed on water (P7h) vs unprimed seeds imbibed on water (UP7h) (germination after osmopriming). Biological replicates: 2 replicates for comparison PEG soaking, drying after soaking, full osmopriming process and germination after osmopriming.
Project description:In this work we studied the participation of RdDM pathway in response to salinity during germination, we found that the RdDM promotes germination while AGO4 null mutant negatively regulates the germination process.