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: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: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: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:Hyperosmotic stress caused by drought and salinity is a significant environmental threat that limits plant growth and agricultural productivity. Osmotic stress induces diverse responses in plants including Ca2+ signaling, accumulation of the stress hormone abscisic acid (ABA), reprogramming of gene expression, and altering growth. Despite intensive investigation, no global regulators of all of these responses have been identified. Here, we show that the Ca2+-responsive phospholipid binding BONZAI (BON) proteins are critical for all of these osmotic stress responses. A Ca2+-imaging-based forward genetic screen identified a loss-of-function bon1 mutant with a reduced cytosolic Ca2+ signal in response to hyperosmotic stress. The loss-of-function mutants of the BON1 gene family, bon1bon2bon3, are impaired in the induction of gene expression and ABA accumulation in response to osmotic stress. In addition, the bon mutants are hypersensitive to osmotic stress in growth inhibition. BON genes have been shown to negatively regulate plant immune responses mediated by intracellular immune receptor NLR genes including SNC1. We found that the defects of the bon mutants in osmotic stress responses were suppressed by mutations in the NLR gene SNC1 or the immunity regulator PAD4. Our findings indicate that NLR signaling represses osmotic stress responses and that BON proteins suppress NLR signaling to enable global osmotic stress responses in plants.
Project description:Environmental conditions contributing to abiotic stresses such as drought and salinity result in large annual economic losses around the world. As sessile organisms, plants cannot escape the environmental stresses they encounter, but instead must adapt to survive. Previous studies investigating osmotic and/or salt responses have largely focused on understanding short-term responses (0-1h) at the transcriptomic, proteomic and phosphoproteomic level; however, our understanding of intermediate to longer-term adaptation (24h - days) is relatively limited. In addition to protein abundance and phosphorylation changes, recent evidence suggests reversible protein acetylation may be important for abiotic stress responses. Therefore, to characterize the effects of osmotic and salt stress, we undertook a label-free proteomic and PTMomic analysis of Arabidopsis roots exposed to 300mM Mannitol and 150mM NaCl for 24 h. We quantitatively assessed protein abundance, phosphorylation and acetylation.
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.