SubclassⅢsucrose nonfermenting1-related protein kinase 2s(SnRK2s)function in ABA and abiotic stress responses by unknown mechanisms.We found that osmotic stress/ABA-activated protein kinase 10(SAPK10),a member of ric...SubclassⅢsucrose nonfermenting1-related protein kinase 2s(SnRK2s)function in ABA and abiotic stress responses by unknown mechanisms.We found that osmotic stress/ABA-activated protein kinase 10(SAPK10),a member of rice SnRK2s,physically interacted with CBL-interacting protein kinase 1(OsCIPK1).OsCIPK1 expression was up-regulated by ABA and PEG treatment,and overexpression increased the ABA sensitivity of seed germination and root growth and plant osmotic stress tolerance.Osmotic stress or ABA-induced activation of OsCIPK1 is dependent on SAPK10.SAPK10 phosphorylates Thr-24 of OsCIPK1 in vitro,and this phosphorylation increases the activity of OsCIPK1 and positively regulates the function of OsCIPK1 in ABA responses and plant osmotic stress tolerance.This study suggests that OsCIPK1 is a direct phosphorylated substrate of SAPK10,and SAPK10-mediated phosphorylation of OsCIPK1 functions in ABA signaling and increases rice osmotic stress tolerance.展开更多
●AIM:To explore whether autophagy functions as a cellular adaptation mechanism in lens epithelial cells(LECs)under hyperosmotic stress.●METHODS:LECs were treated with hyperosmotic stress at the concentration of 270,...●AIM:To explore whether autophagy functions as a cellular adaptation mechanism in lens epithelial cells(LECs)under hyperosmotic stress.●METHODS:LECs were treated with hyperosmotic stress at the concentration of 270,300,400,500,or 600 mOsm for 6,12,18,24h in vitro.Polymerase chain reaction(PCR)was employed for the mRNA expression of autophagyrelated genes,while Western blotting detected the targeted protein expression.The transfection of stub-RFP-sens-GFPLC3 autophagy-related double fluorescence lentivirus was conducted to detect the level of autophagy flux.Scanning electron microscopy was used to detect the existence of autolysosome.Short interfering RNA of autophagy-related gene(ATG)7,transient receptor potential vanilloid(TRPV)1 overexpression plasmid,related agonists and inhibitors were employed to their influence on autophagy related pathway.Flow cytometry was employed to test the apoptosis and intracellular Ca^(2+)level.Mitochondrial membrane potential was measured by JC-1 staining.The cell counting kit-8 assay was used to calculate the cellular viability.The wound healing assay was used to evaluate the wound closure rate.GraphPad 6.0 software was utilized to evaluate the data.●RESULTS:The hyperosmotic stress activated autophagy in a pressure-and time-dependent manner in LECs.Beclin 1 protein expression and conversion of LC3B II to LC3B I increased,whereas sequestosome-1(SQSTM1)protein expression decreased.Transient Ca^(2+)influx was stimulated caused by hyperosmotic stress,levels of mammalian target of rapamycin(mTOR)phosphorylation decreased,and the level of AMP-activated protein kinase(AMPK)phosphorylation increased in the early stage.Based on this evidence,autophagy activation through the Ca^(2+)-dependent AMPK/mTOR pathway might represent an adaptation process in LECs under hyperosmotic stress.Hyperosmotic stress decreased cellular viability and accelerated apoptosis in LECs and cellular migration decreased.Inhibition of autophagy by ATG7 knockdown had similar results.TRPV1 overexpression increased autophagy and might be crucial in the occurrence of autophagy promoted by hyperosmotic stress.●CONCLUSION:A combination of hyperosmotic stress and autophagy inhibition may be a promising approach to decrease the number of LECs in the capsular bag and pave the way for improving prevention of posterior capsular opacification and capsular fibrosis.展开更多
Nitraria sibirica Pall.is an important shrub with a strong salt-alkali tolerance,but the mechanism underlying this tolerance remains obscure.In this study,N.sibirica,with salt-sensitive Vigna radiata(Linn.)Wilczek as ...Nitraria sibirica Pall.is an important shrub with a strong salt-alkali tolerance,but the mechanism underlying this tolerance remains obscure.In this study,N.sibirica,with salt-sensitive Vigna radiata(Linn.)Wilczek as the control,was subjected to transient salt stress(100 mM NaCl),alkali stress(50 mM Na_(2)CO_(3)),and osmotic stress(175 mM mannitol).The ionic fluxes of Na^(+)and K^(+)in the root apical region were measured.Results show that,under salt and alkali stress,N.sibirica roots exhibited higher capacities to limit Na+influx and reduce K+efflux,thereby resulting in lower Na^(+)/K^(+)ratios compared with V.radiata roots.Alkali stress induced stronger Na^(+)influx and K+efflux in the root salt stress treatment;Na^(+)influx was mainly observed in the root cap,while K^(+)efflux was mainly observed in the elongation zone.While under osmotic stress,N.sibirica roots showed stronger Na+efflux and weaker K+efflux than V.radiata roots.Na+efflux was mainly observed in the root elongation zone,while K+efflux was in the root cap.These results reveal the ionic strategy of N.sibirica in response to transient salt,alkali,and osmotic stresses through the regulation of Na+/K+flux homeostasis.展开更多
Intensively farmed crops used to experience numerous environmental stresses.Among these,shade and drought significantly influence the morpho-physiological and biochemical attributes of plants.However,the interactive e...Intensively farmed crops used to experience numerous environmental stresses.Among these,shade and drought significantly influence the morpho-physiological and biochemical attributes of plants.However,the interactive effect of shade and drought on the growth and development of soybean under dense cropping systems has not been reported yet.This study investigated the interactive effect of PEG-induced osmotic stress and shade on soybean seedlings.The soybean cultivar viz.,C-103 was subjected to PEG-induced osmotic stress from polyethylene glycol 6000(PEG-6000)under shading and non-shading conditions.PEG-induced osmotic stress significantly reduced the relative water contents,morphological parameters,carbohydrates and chlorophyll contents under both light environments.A significant increase was observed in osmoprotectants,reactive oxygen species and antioxidant enzymes in soybean seedlings.Henceforth,the findings revealed that,seedlings grown under non-shading conditions produced more malondialdehyde and hydrogen peroxide contents as compared to the shade-treated plants when subjected to PEG-induced osmotic stress.Likewise,the shaded plants accumulated more sugars and proline than non-shaded ones under drought stress.Moreover,it was found that nonshaded grown plants were more sensitive to PEG-induced osmotic stress than those exposed to shading conditions,which suggested that shade could boost the protective mechanisms against osmotic stress or at least would not exaggerate the adverse effects of PEG-induced osmotic stress in soybean seedlings.展开更多
Osmotic stress promotes somatic embryogenesis of Fraxinus mandshurica,which leads to accumulation of reactive oxygen species(ROS).The single pieces of cotyledons of F.mandshurica were used as explants to induce somati...Osmotic stress promotes somatic embryogenesis of Fraxinus mandshurica,which leads to accumulation of reactive oxygen species(ROS).The single pieces of cotyledons of F.mandshurica were used as explants to induce somatic embryogenesis in osmotic-stress medium.Furthermore,the hydrogen peroxide H_(2)O_(2) content of explanted cells was varied by adding exogenous H_(2)O_(2) or catalase solution to assess the effects of the exogenous H_(2)O_(2)on somatic embryogenesis,intracellular H_(2)O_(2)accumulation,and the relationship between signaling mediated by ROS or reactive nitrogen species.The results revealed that exogenous H_(2)O_(2)(100?300μmol L^(–1))increased the number of somatic embryos.On 60th day of exogenous H_(2)O_(2)(200μmol L^(–1))treatment,the number of somatic embryos of explants treated,which was 136.54%,was higher than the control.Moreover,exogenous H_(2)O_(2)(100μmol L^(–1))significantly increased the intracellular H_(2)O_(2)content and enhanced the activities of superoxidase dismutase and peroxidase.Finally,exogenous H_(2)O_(2)(100μmol L^(–1))activated the intracellular non-enzymatic pathway for nitric oxide(NO)synthesis.The somatic embryogenesis in broadleaf trees increases with the change of endogenic ROS content,and depends on the upregulation of antioxidant enzymes.Both H_(2)O_(2)and NO,as signaling molecules,were found to be involved in the process of somatic embryogenesis in broadleaf trees.In the process of exogenous H_(2)O_(2)promoting somatic embryogenesis,NO synthesis depended on non-enzymatic reactions.These results provide a scientific basis for resolving the mechanism by which ROS levels are regulated during somatic embryogenesis of broadleaf trees and establish a reasonable and efficient technology system for regulating somatic embryogenesis of trees.展开更多
Plants maintain water balance by varying hydraulic properties, and plasma membrane intrinsic proteins(PIPs) may be involved in this process. Leaf xylem and root hydraulic conductivity and the m RNA contents of four hi...Plants maintain water balance by varying hydraulic properties, and plasma membrane intrinsic proteins(PIPs) may be involved in this process. Leaf xylem and root hydraulic conductivity and the m RNA contents of four highly expressed Zm PIP genes(Zm PIP1;1, Zm PIP1;2, Zm PIP2;2, and Zm PIP2;5) in maize(Zea mays) seedlings were investigated. Under well-watered conditions, leaf hydraulic conductivity(K_(leaf)) varied diurnally and was correlated with whole-plant hydraulic conductivity. Similar diurnal rhythms of leaf transpiration rate(E), K_(leaf) and root hydraulic conductivity(K_(root)) in well-watered plants are important for maintaining whole-plant water balance. After 2 h of osmotic stress treatment induced by 10% polyethylene glycol 6000, the K_(root) of stressed plants decreased but K_(leaf) increased, compared with well-watered plants. The m RNA contents of four Zm PIPs were significantly up-regulated in the leaves of stressed plants, especially for Zm PIP1;2. Meanwhile, Zm PIP2;5 was significantly down-regulated in the roots of stressed plants. After 4 h of osmotic stress treatment, the E and leaf xylem water potentials of stressed plants unexpectedly increased. The increase in K_(leaf) and a partial recovery of K_(root) may have contributed to this process. The m RNA content of Zm PIP1;2 but not of the other three genes was up-regulated in roots at this time. In summary, the m RNA contents of these four Zm PIPs associated with K_(leaf) and K_(root) change in maize seedlings during short-term osmotic stress, especially for Zm PIP1;2 and Zm PIP2;5, which may help to further reveal the hydraulic resistance adjustment role of Zm PIPs.展开更多
In plants,glycerol-3-phosphate dehydrogenase(GPDH)catalyzes the interconversion of glycerol-3-phosphate(G3P)and dihydroxyacetone phosphate(DHAP)coupled to the reduction/oxidation of the nicotinamide adenine dinucleoti...In plants,glycerol-3-phosphate dehydrogenase(GPDH)catalyzes the interconversion of glycerol-3-phosphate(G3P)and dihydroxyacetone phosphate(DHAP)coupled to the reduction/oxidation of the nicotinamide adenine dinucleotide(NADH)pool,and plays a central role in glycerolipid metabolism and stress response.Previous studies have focused mainly on the NAD+-dependent GPDH isoforms,neglecting the role of flavin adenine dinucleotide(FAD)-dependent GPDHs.We isolated and characterized three mitochondrialtargeted FAD-GPDHs in soybean,of which one isoform(GmGPDH12)showed a significant transcriptional response to NaCl and mannitol treatments,suggesting the existence of a major FAD-GPDH isoform acting in soybean responses to salt and osmotic stress.An enzyme kinetic assay showed that the purified GmGPDH12 protein possessed the capacity to oxidize G3P to DHAP in the presence of FAD.Overexpression and RNA interference of GmGPDH12 in soybean hairy roots resulted in elevated tolerance and sensitivity to salt and osmotic stress,respectively.G3P contents were significantly lower in GmGPDH12-overexpressing hair roots and higher in knockdown hair roots,indicating that GmGPDH12 was essential for G3P catabolism.A significant perturbation in redox status of NADH,ascorbic acid(ASA)and glutathione(GSH)pools was observed in GmGPDH12-knockdown plants under stress conditions.The impaired redox balance was manifested by higher reactive oxygen species generation and consequent cell damage or death;however,overexpressing plants showed the opposite results for these traits.GmGPDH12 overexpression contributed to maintaining constant respiration rates under salt or osmotic stress by regulating mRNA levels of key mitochondrial respiratory enzymes.This study provides new evidence for the roles of mitochondria-localized GmGPDH12 in conferring resistance to salt or osmotic stress by maintaining cellular redox homeostasis,protecting cells and respiration from oxidative injury.展开更多
Thirteen different inbred lines in relation to the type of grain and life cycles were characterized by testing for osmotic stress associated with salinity. The identification of tolerant genotypes would be an effectiv...Thirteen different inbred lines in relation to the type of grain and life cycles were characterized by testing for osmotic stress associated with salinity. The identification of tolerant genotypes would be an effective strategy to overcome the saline stress. Osmotic stress reduces immediately the expansion of the roots and young leaves which determine a reduction in the size of the plant. A completely randomized design was adopted to test seedlings under controlled conditions of light and temperature. Two treatments were used: 0 mM NaCl (as control) and 100 mM NaCl. After 15 days of complete salinization, the seedlings were harvested and several morphological traits were measured. The morphological traits of growth were leaf growth (Ar1, Ar2, Ar3 and Ar4), dry masses of shoot and root (SDM and RDM, respectively). Also, traits associated with water economy were registered: leaf water loss (LWL) and relative water content (RWC). The morphological traits were expressed in relative terms, while the traits associated with the economy of water were expressed in absolute terms. Uni and multivariate techniques were applied to identify genotypes with divergent behaviors to osmotic stress tolerance. Also, a Tolerance Index was employed to identify superior genotypes. Four clusters were obtained after applying a Cluster Analysis and Principal Component Analysis (PCA). The genotypes were compared to each other with a test of DMS. The results obtained with different statistical techniques converged. Some variables presented a differential weight classification of genotypes. The morphological traits like RDM, SDM, Ar3, Ar4 and Ar5 were the most discriminating. Tolerance Index allowed to classify genotypes, thus SC2 and AD3 lines were that reached highest value of the index and therefore would be tolerant lines, while AF3 and LP3 had a low index and were seen as sensible.展开更多
Objectives: Exposing skin to moderate ionic osmotic stress (MIOS) triggers several biochemical responses. The objective of this work is to reveal the mechanism triggered by MIOS on the skin surface. Furthermore, this ...Objectives: Exposing skin to moderate ionic osmotic stress (MIOS) triggers several biochemical responses. The objective of this work is to reveal the mechanism triggered by MIOS on the skin surface. Furthermore, this work aims to study the involvement of the Nrf2 (nuclear factor erythroid-2-related factor 2) pathway, activated by MIOS, and its beneficial effect in protecting skin against stress via the stimulation of phase II enzymes. Methods: HaCaT cells and human skin organ culture were exposed to Dead Sea Water (DSW) as MIOS inducers and the induction of internal ROS elevation, Nrf2 translocation, mRNA gene expressions of the phase II enzymes, heme-oxygenase 1 (HO1), and Catalase (CAT) were determined. Results: Skin exposure to MIOS increases Nrf2 translocation to the nucleus, leading to increased levels of ROS, HO1, and CAT. Furthermore, exposing skin to MIOS promotes protection against UVB-related risks. This is demonstrated by attenuation of the expression of biomarkers, related to UVB-induced damage, Caspase-3, IL-8, and IL-1β. Conclusions: Skin exposure to MIOS leads to the activation of Nrf2 skin defense pathway and, therefore, could present beneficial advantages to human skin health, as demonstrated on human skin models. The beneficial effects of MIOS, induced by DSW are significantly superior to eq. NaCl brine, suggests that MIOS protection of skin against stress is partially related to specific mineral combinations.展开更多
The effects of osmotic stress on the ATPase activity, the contents of —SH group and conjugated polyamines in mitochondrial membrane from wheat seedling [Triticum aestivum L. cv. Yumai No.18(drought-tolerant) and cv. ...The effects of osmotic stress on the ATPase activity, the contents of —SH group and conjugated polyamines in mitochondrial membrane from wheat seedling [Triticum aestivum L. cv. Yumai No.18(drought-tolerant) and cv. Yumai No.9(drought-sensitive)] roots were investigated. The results showed that ATPase activity and —SH group content decreased with polyethylene glycol(PEG) 6000(-0.55 MPa) treatment for 7 d, in concert with the decrease of the ratio of noncovalently conjugated spermidine(NCC-Spd)/noncovalently conjugated putrescine(NCC-Put) and increase of the covalently conjugated putrescine(CC-Put). Osmotic stress injury to Yangmai No.9 seedlings was alleviated greatly with 1 mmol/L exogenous spermidine(Spd), in concert with marked increases of the ratio of NCC-Spd/NCC-Put, —SH group contents and ATPase activity in mitochondrial membrane. Under osmotic stress, the concomitant treatment of Yumai No.18 seedlings with methylglyoxyl bis(guanylhydrazone) (MGBG), an inhibitor of S-adenosyl methionine decarboxylase(SAMDC), and phenanthrolin (o-Phen), an inhibitor of transglutaminase(TGase), caused a significant decrease of the ratio of NCC-Spd / NCC-Put, CC-Put contents, respectively, in concert with the marked decreases of ATPase activity, —SH group content and its tolerance to osmotic stress. All the results above suggested that osmotic stress tolerance of wheat seedlings was associated with the ATPase activity, the contents of —SH group, NCC-Spd and CC-Put in mitochondrial membrane.展开更多
The osmotic pressure represented as a sign of plant tolerance or sensitive to salinity stress. In the following plants, the increase in OP seems to be a manner of defense mechanism to survive. OP increased in shoots o...The osmotic pressure represented as a sign of plant tolerance or sensitive to salinity stress. In the following plants, the increase in OP seems to be a manner of defense mechanism to survive. OP increased in shoots of maize, shoot and root of wheat and cotton plants was concomitant with shoot soluble sugar, root soluble protein and shoot and root amino acids of maize plants. However, in wheat the increase in OP was related with increase of root soluble sugar and protein of shoots and roots. In cotton plants, the elevation of OP was run parallel with increase soluble sugar of shoots and roots, shoot soluble protein and root amino acids. The increase in OP was related with a marked and significant reduction in the water content of these plants. However, the decrease in OP of shoot and root of broad bean was related with the reduction of shoots and roots soluble sugar, protein and root amino acids of broad bean. While the OP becomes more or less unchanged in shoots and tended to decrease in root of parsley plants, this concomitant with unchanged trend in the shoots amino acids and reduction in root soluble sugar and root amino acids. Run with previous trend values of OP and metabolites of parsley plants were related with stable values in shoot water content and reduction in root water content. With GA<sub>3</sub> and kinetin treatments mostly increase the values OP which parallel with increase and soluble sugar, soluble protein and amino acids contents of shoots and roots of maize, wheat, cotton, broad bean and parsley plants with NaCl increasing. This related with increase water uptake by roots in these plants. The results indicated that kinetin had a more effective to shoot maize, both organs of wheat, broad bean and parsley plants in response to salinity stress while GA<sub>3</sub> was more effective on cotton plants especially at higher levels of salinity. Thus plants strategy differed in their tolerance to salinity stress according to their species and differed also according to the different organs of the same plants and kinetin treatment induced highly positively affect than GA<sub>3</sub> treatments.展开更多
Leaf senescence is often caused by water deficit and the chimeric gene PSAG12-IPT is an auto-regulated gene delaying leaf senescence. Using in vitro leaf discs culture system, the changes of contents of chlorophylls, ...Leaf senescence is often caused by water deficit and the chimeric gene PSAG12-IPT is an auto-regulated gene delaying leaf senescence. Using in vitro leaf discs culture system, the changes of contents of chlorophylls, carotenoids, soluble protein and thiobarbituric acid reactive substance (TBARS) and antioxidant enzymes activities were investigated during leaf senescence of PSAGl2-IPT modified gerbera induced by osmotic stress compared with the control plant (wild type). Leaf discs were incubated in 20%, 40% (w/v) polyethylene glycol (PEG) 6 000 nutrient solution for 20 h under continuous light [130 μmol/(m2·s)]. The results showed that the contents of chlorophylls, carotenoids and soluble protein were decreased by osmotic stress with the decrease being more pronounced at 40% PEG, but that, at the same PEG concentration the decrease in the transgenic plants was significantly lower than that in the control plant. The activities of superoxide dismutase (SOD), catalases (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPX) and dehydroascorbate reductase (DHAR) were stimulated by PEG treatment. However, the increases were higher in PSAG12-IPT transgenic plants than in the control plants, particularly at 40% PEG treatment. Lipid peroxidation (TBARS content) was increased by PEG treatment with the increase being much lower in transgenic plant than in the control plant. It could be concluded that the increases in the activities of antioxidant enzymes including SOD, CAT, APX, GPX and DHAR were responsible for the delay of leaf senescence induced by osmotic stress.展开更多
In order to investigate the effect of water channel blocker HgCl2 on the hydraulic resistance in roots of maize seedlings,a xylem pressure probe was used to monitor the changes in root xylem pressure in response to Na...In order to investigate the effect of water channel blocker HgCl2 on the hydraulic resistance in roots of maize seedlings,a xylem pressure probe was used to monitor the changes in root xylem pressure in response to NaCl-or mannitol-induced osmotic stresses before and after the application of HgCl2.When the maize roots were subjected to 500 μmol L-1 HgCl2 in root bathing solution,not only a considerable decline in xylem pressure(increase in xylem tension) was observed,but the loss of responsiveness of the plant to both salt-and mannitol-induced osmotic stresses in terms of xylem pressure change was seen as well when the transpiration rate of the plant was not significantly changed.The results are similar but different from the reversed osmosis by the Fenton reaction in the internodes of Chara coralline,showing that the mechanisms of water transport across cell membrane in plant roots are far more complicated than expected.展开更多
We investigated the influence of different levels of osmotic stress on growth and development in selected wild almond species(eight Prunus spp.) grown in vitro. The study, while endorsing the efficacy of in vitro scre...We investigated the influence of different levels of osmotic stress on growth and development in selected wild almond species(eight Prunus spp.) grown in vitro. The study, while endorsing the efficacy of in vitro screening of auxiliary buds of wild almond for osmotic stress tolerance, showed species variability in its response to osmotic stress. Osmotic stress reduced growth and development of all the species. However, the putative tolerant Prunus spp. showed better performance than the putative susceptible genotypes. On average there was an 80% decrease in shoot dry weight at-1.2 MPa. Reduction in shoot weight was more common in osmotic stress-susceptible species in the section labeled ‘Euamygdalus'. The tolerant Prunus species produced smaller changes in biochemical responses than the sensitive cultivars for malondialdehyde content, catalase activity, relative permeability of protoplast membranes, and net photosynthetic rate. The tolerant species maintained cell integrity better than drought sensitive species. Wild almond species in the section labeled ‘Spartioides'(Prunus arabica(Olivier) Neikle, Prunus glauca (Browicz) A.E. Murray, Prunus scoparia Spach) and ‘Lycioides'(Prunus lycioides Spach, Prunus reuteri Bossi. et Bushe) were best adapted to osmotic stress. Increase in chlorophyll concentration and leaf thickness under high osmotic stress can be considered as preliminary selection parameters for osmotic stress tolerance in Prunus spp. The study confirmed the efficacy of the in vitro method for screening of large number of genotypes for osmotic stress tolerance in wild almond species.展开更多
Clarifying the stress signal transduction pathway would be helpful for understanding the abiotic stress resistance mechanism in apple(Malus×domestica Borkh.)and could assist in the development of new varieties wi...Clarifying the stress signal transduction pathway would be helpful for understanding the abiotic stress resistance mechanism in apple(Malus×domestica Borkh.)and could assist in the development of new varieties with high stress tolerance by genetic engineering.The key NAC transcription factor SND1,which is involved in the lignin biosynthesis process in apple,was functionally analyzed.The results of the stress treatments indicated that MdSND1 could be induced by salt,mannitol and ABA.Compared with wild-type GL-3 plants,MdSND1-overexpressing apple plants with greater antioxidant capacity and lignin were more resistant to salt and simulated osmotic stress,while RNAi plants were more vulnerable.Additionally,molecular experiments confirmed that MdSND1 could regulate the biosynthesis of lignin by activating the transcription of MdMYB46/83.Moreover,genes known to be involved in the stress signal transduction pathway(MdAREB1A,MdAREB1B,MdDREB2A,MdRD29A,and MdRD22)were screened for their close correlations with the expression of MdSND1 and the response to salt and osmotic stress.Multiple verification tests further demonstrated that MdSND1 could directly bind to these gene promoters and activate their transcription.The above results revealed that MdSND1 is directly involved in the regulation of lignin biosynthesis and the signal transduction pathway involved in the response to both salt and osmotic stress in apple.展开更多
Aquaporins(AQPs)are a family of integral membrane proteins that have been shown to be important for osmoregulation in many vertebrates.To identify potential stress resistance-related aqp genes in salinity adaptation o...Aquaporins(AQPs)are a family of integral membrane proteins that have been shown to be important for osmoregulation in many vertebrates.To identify potential stress resistance-related aqp genes in salinity adaptation of the roughskin sculpin Trachidermus fasciatus,we investigated the time-course expression dynamics of seven aquaporin genes(aqp1,4,7,8,10,11 and 12)in three osmoregulatory tissues(kidney,gill and intestine)and one metabolic tissue(liver).The fish were subjected to two different acute osmotic treatments(seawater-tofreshwater transfer respectively achieved in 1 h and 24 h,namely,E-acute and acute group).The expression profiling of the seven aqp genes were performed using quantitative real-time PCR(qRT-PCR).At the time of all sampling time points(0 h,12 h,24 h and 48 h),no expression of aqp4 was found in the gill,liver and intestine;no expression of aqp7 was found in the gill and liver.Significant differences of aqp expression were determined in the four target tissues,and the mRNA levels were largely variable among gene members and tissues.Similar patterns of the time-course expression were detected in most of the aqp genes in T.fasciatus between the two acute groups,except that only one gene(aqp12)in the kidney and three genes(aqp7,aqp8 and aqp10)in the intestine revealed different expression patterns.These results suggest that the expression response of aqp genes was similar under osmotic changes with different rates.展开更多
Trehalose is a non-reducing disaccharide with high stability and strong water absorption properties that can improve the resistance of organisms to various abiotic stresses.Trehalose-6-phosphate synthase(TPS)plays imp...Trehalose is a non-reducing disaccharide with high stability and strong water absorption properties that can improve the resistance of organisms to various abiotic stresses.Trehalose-6-phosphate synthase(TPS)plays important roles in trehalose metabolism and signaling.In this study,the full-length cDNA of ThTPS was cloned from Tamarix hispida Willd.A phylogenetic tree including ThTPS and 11 AtTPS genes from Arabidopsis indicated that the ThTPS protein had a close evolutionary relationship with AtTPS7.However,the function of At TPS7 has not been determined.To analyze the abiotic stress tolerance function of ThTPS,the expression of ThTPS in T.hispida under salt and drought stress and JA,ABA and GA3 hormone stimulation was monitored by qRT-PCR.The results show that ThTPS expression was clearly induced by all five of these treatments at one or more times,and salt stress caused particularly strong induction of Th TPS in the roots of T.hispida.The ThTPS gene was transiently overexpressed in T.hispida.Both physiological indexes and staining results showed that ThTPS gene overexpression increased salt and osmotic stress tolerance in T.hispida.Overall,the Th TPS gene can respond to abiotic stresses such as salt and drought,and its overexpression can significantly improve salt and osmotic tolerance.These findings establish a foundation to better understand the responses of TPS genes to abiotic stress in plants.展开更多
The aims of this study was to examine the effect of the osmotic (NaCl) water stress on, growth and accumulation of endogenous compatible solutes of Bacillus amyloliquefaciens and Microbacterium oleovorans, biocontrol ...The aims of this study was to examine the effect of the osmotic (NaCl) water stress on, growth and accumulation of endogenous compatible solutes of Bacillus amyloliquefaciens and Microbacterium oleovorans, biocontrol agents against Fusarium verticillioides. Triptic soya broth media were modified ionically to 0.99;0.98;0.97 and 0.96 aw with NaCl. The endogenous contents of the intracellular compatible solutes glycine-betaine and ectoine were quantified. Cells grown under ionic solute stress showed accumulation of significant amounts of both amino acids in all treatments. The growth rate of F. verticillioides was decreased significantly by interaction with B. amyloliquefaciens and M. oleovorans physiologically adapted at 0.96 aw. This study have demonstrated the ability to synthesize betaine and ectoine under high-osmolality conditions of B. amyloliquefaciens and M. oleovorans cells. Such ecophysiological manipulation, especially to water stress, may increase the potential for biological control of F. verticillioides at field under wider aw conditions.展开更多
PM2 gene (accession number: M80664) with high lysine content from soybean (Glycine max) was found in GenBank by changing three BLASTp parameters. Amino acid composition analysis of PM2 showed that Lys content was on t...PM2 gene (accession number: M80664) with high lysine content from soybean (Glycine max) was found in GenBank by changing three BLASTp parameters. Amino acid composition analysis of PM2 showed that Lys content was on the high level of 18.22%. Protein encoded by PM2 also belonged to the family of late embryogenesis abundant (LEA) proteins, which was considered that it had a strong relation with the abiotic stress resistance. In this experiment, PM2 gene was obtained from dry soybean seeds by RT-PCR, plant expression vector pEMTPM2 was constructed, and then transformed into tobacco by using agrobacterium-mediated method. Eight salt and drought tolerant lines were obtained from 31 differentiated lines. Real-time PCR showed that PM2 gene overexpressed in all four PCR positive lines with the osmotic stress resistance. These results confirmed that the overexpression of PM2 gene enhanced the osmotic stress resistance of transgenic tobacco.展开更多
Changes in sucrose metabolism in response to salt (NaCl) and water (polyethylene glycol, PEG6000) iso-osmotic stresses were measured in tomato cultivar Liaoyuan Duoli (Solanum lycopersicum L.) and the objective was to...Changes in sucrose metabolism in response to salt (NaCl) and water (polyethylene glycol, PEG6000) iso-osmotic stresses were measured in tomato cultivar Liaoyuan Duoli (Solanum lycopersicum L.) and the objective was to provide a new evidence for the relationship between salt and osmotic stresses. The carbohydrate contents, as well as sucrose metabolizing enzymes activities and transcript levels were determined. The results indicated that soluble sugar and hexoses accumulated to higher levels and the contents of sucrose and starch were lower in mature fruit under the two stress treatments. Salt and water stresses can enhance the invertase and sucrose synthase activities of tomato fruit in a long period of time (45-60 days after anthesis), and elevate the expression of soluble acid invertase mRNA. It showed that two different stresses could also regulate the soluble acid invertase activity by controlling its gene expression. The activity of sucrose synthase was linked to the changes in soluble sugar levels but not with transcript levels. The effects of salt and water stress treatments on sucrose phosphate synthase activities were weak.展开更多
基金supported by grants from the National Natural Science Foundation of China(31971824,32170316)。
文摘SubclassⅢsucrose nonfermenting1-related protein kinase 2s(SnRK2s)function in ABA and abiotic stress responses by unknown mechanisms.We found that osmotic stress/ABA-activated protein kinase 10(SAPK10),a member of rice SnRK2s,physically interacted with CBL-interacting protein kinase 1(OsCIPK1).OsCIPK1 expression was up-regulated by ABA and PEG treatment,and overexpression increased the ABA sensitivity of seed germination and root growth and plant osmotic stress tolerance.Osmotic stress or ABA-induced activation of OsCIPK1 is dependent on SAPK10.SAPK10 phosphorylates Thr-24 of OsCIPK1 in vitro,and this phosphorylation increases the activity of OsCIPK1 and positively regulates the function of OsCIPK1 in ABA responses and plant osmotic stress tolerance.This study suggests that OsCIPK1 is a direct phosphorylated substrate of SAPK10,and SAPK10-mediated phosphorylation of OsCIPK1 functions in ABA signaling and increases rice osmotic stress tolerance.
文摘●AIM:To explore whether autophagy functions as a cellular adaptation mechanism in lens epithelial cells(LECs)under hyperosmotic stress.●METHODS:LECs were treated with hyperosmotic stress at the concentration of 270,300,400,500,or 600 mOsm for 6,12,18,24h in vitro.Polymerase chain reaction(PCR)was employed for the mRNA expression of autophagyrelated genes,while Western blotting detected the targeted protein expression.The transfection of stub-RFP-sens-GFPLC3 autophagy-related double fluorescence lentivirus was conducted to detect the level of autophagy flux.Scanning electron microscopy was used to detect the existence of autolysosome.Short interfering RNA of autophagy-related gene(ATG)7,transient receptor potential vanilloid(TRPV)1 overexpression plasmid,related agonists and inhibitors were employed to their influence on autophagy related pathway.Flow cytometry was employed to test the apoptosis and intracellular Ca^(2+)level.Mitochondrial membrane potential was measured by JC-1 staining.The cell counting kit-8 assay was used to calculate the cellular viability.The wound healing assay was used to evaluate the wound closure rate.GraphPad 6.0 software was utilized to evaluate the data.●RESULTS:The hyperosmotic stress activated autophagy in a pressure-and time-dependent manner in LECs.Beclin 1 protein expression and conversion of LC3B II to LC3B I increased,whereas sequestosome-1(SQSTM1)protein expression decreased.Transient Ca^(2+)influx was stimulated caused by hyperosmotic stress,levels of mammalian target of rapamycin(mTOR)phosphorylation decreased,and the level of AMP-activated protein kinase(AMPK)phosphorylation increased in the early stage.Based on this evidence,autophagy activation through the Ca^(2+)-dependent AMPK/mTOR pathway might represent an adaptation process in LECs under hyperosmotic stress.Hyperosmotic stress decreased cellular viability and accelerated apoptosis in LECs and cellular migration decreased.Inhibition of autophagy by ATG7 knockdown had similar results.TRPV1 overexpression increased autophagy and might be crucial in the occurrence of autophagy promoted by hyperosmotic stress.●CONCLUSION:A combination of hyperosmotic stress and autophagy inhibition may be a promising approach to decrease the number of LECs in the capsular bag and pave the way for improving prevention of posterior capsular opacification and capsular fibrosis.
基金supported by the Natural Science Foundation of Xinjiang Uygur Autonomous Region(No.2019D01C069)Natural Science Foundation of Xinjiang University(No.62031224614)。
文摘Nitraria sibirica Pall.is an important shrub with a strong salt-alkali tolerance,but the mechanism underlying this tolerance remains obscure.In this study,N.sibirica,with salt-sensitive Vigna radiata(Linn.)Wilczek as the control,was subjected to transient salt stress(100 mM NaCl),alkali stress(50 mM Na_(2)CO_(3)),and osmotic stress(175 mM mannitol).The ionic fluxes of Na^(+)and K^(+)in the root apical region were measured.Results show that,under salt and alkali stress,N.sibirica roots exhibited higher capacities to limit Na+influx and reduce K+efflux,thereby resulting in lower Na^(+)/K^(+)ratios compared with V.radiata roots.Alkali stress induced stronger Na^(+)influx and K+efflux in the root salt stress treatment;Na^(+)influx was mainly observed in the root cap,while K^(+)efflux was mainly observed in the elongation zone.While under osmotic stress,N.sibirica roots showed stronger Na+efflux and weaker K+efflux than V.radiata roots.Na+efflux was mainly observed in the root elongation zone,while K+efflux was in the root cap.These results reveal the ionic strategy of N.sibirica in response to transient salt,alkali,and osmotic stresses through the regulation of Na+/K+flux homeostasis.
基金supported by the National Natural Science Foundation of China(31871552 and 31671445)the Sichuan Science and Technology Program,China(2018HH0108)the Sichuan Innovation Team Project of National Modern Agricultural Industry Technology System,China(sccxtd-2020-20)。
文摘Intensively farmed crops used to experience numerous environmental stresses.Among these,shade and drought significantly influence the morpho-physiological and biochemical attributes of plants.However,the interactive effect of shade and drought on the growth and development of soybean under dense cropping systems has not been reported yet.This study investigated the interactive effect of PEG-induced osmotic stress and shade on soybean seedlings.The soybean cultivar viz.,C-103 was subjected to PEG-induced osmotic stress from polyethylene glycol 6000(PEG-6000)under shading and non-shading conditions.PEG-induced osmotic stress significantly reduced the relative water contents,morphological parameters,carbohydrates and chlorophyll contents under both light environments.A significant increase was observed in osmoprotectants,reactive oxygen species and antioxidant enzymes in soybean seedlings.Henceforth,the findings revealed that,seedlings grown under non-shading conditions produced more malondialdehyde and hydrogen peroxide contents as compared to the shade-treated plants when subjected to PEG-induced osmotic stress.Likewise,the shaded plants accumulated more sugars and proline than non-shaded ones under drought stress.Moreover,it was found that nonshaded grown plants were more sensitive to PEG-induced osmotic stress than those exposed to shading conditions,which suggested that shade could boost the protective mechanisms against osmotic stress or at least would not exaggerate the adverse effects of PEG-induced osmotic stress in soybean seedlings.
基金supported by the National Natural Science Foundation of China(31570596 and 31400535)the Fundamental Research Funds for the Central Universities(2572018BW02)+1 种基金the Innovation Project of State Key Laboratory of Tree Genetics and Breeding(Northeast Forestry University,2016C01)the National Key R&D Program of China(2017YFD0600600)。
文摘Osmotic stress promotes somatic embryogenesis of Fraxinus mandshurica,which leads to accumulation of reactive oxygen species(ROS).The single pieces of cotyledons of F.mandshurica were used as explants to induce somatic embryogenesis in osmotic-stress medium.Furthermore,the hydrogen peroxide H_(2)O_(2) content of explanted cells was varied by adding exogenous H_(2)O_(2) or catalase solution to assess the effects of the exogenous H_(2)O_(2)on somatic embryogenesis,intracellular H_(2)O_(2)accumulation,and the relationship between signaling mediated by ROS or reactive nitrogen species.The results revealed that exogenous H_(2)O_(2)(100?300μmol L^(–1))increased the number of somatic embryos.On 60th day of exogenous H_(2)O_(2)(200μmol L^(–1))treatment,the number of somatic embryos of explants treated,which was 136.54%,was higher than the control.Moreover,exogenous H_(2)O_(2)(100μmol L^(–1))significantly increased the intracellular H_(2)O_(2)content and enhanced the activities of superoxidase dismutase and peroxidase.Finally,exogenous H_(2)O_(2)(100μmol L^(–1))activated the intracellular non-enzymatic pathway for nitric oxide(NO)synthesis.The somatic embryogenesis in broadleaf trees increases with the change of endogenic ROS content,and depends on the upregulation of antioxidant enzymes.Both H_(2)O_(2)and NO,as signaling molecules,were found to be involved in the process of somatic embryogenesis in broadleaf trees.In the process of exogenous H_(2)O_(2)promoting somatic embryogenesis,NO synthesis depended on non-enzymatic reactions.These results provide a scientific basis for resolving the mechanism by which ROS levels are regulated during somatic embryogenesis of broadleaf trees and establish a reasonable and efficient technology system for regulating somatic embryogenesis of trees.
基金financially supported by the National Natural Science Foundation of China (31400527, 31501276)the National High-Tech R&D Program of China (2011AA100504)+1 种基金the Project 111 of the Ministry of Education of China (B12007)the Fund of State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, China (K318009902-1408)
文摘Plants maintain water balance by varying hydraulic properties, and plasma membrane intrinsic proteins(PIPs) may be involved in this process. Leaf xylem and root hydraulic conductivity and the m RNA contents of four highly expressed Zm PIP genes(Zm PIP1;1, Zm PIP1;2, Zm PIP2;2, and Zm PIP2;5) in maize(Zea mays) seedlings were investigated. Under well-watered conditions, leaf hydraulic conductivity(K_(leaf)) varied diurnally and was correlated with whole-plant hydraulic conductivity. Similar diurnal rhythms of leaf transpiration rate(E), K_(leaf) and root hydraulic conductivity(K_(root)) in well-watered plants are important for maintaining whole-plant water balance. After 2 h of osmotic stress treatment induced by 10% polyethylene glycol 6000, the K_(root) of stressed plants decreased but K_(leaf) increased, compared with well-watered plants. The m RNA contents of four Zm PIPs were significantly up-regulated in the leaves of stressed plants, especially for Zm PIP1;2. Meanwhile, Zm PIP2;5 was significantly down-regulated in the roots of stressed plants. After 4 h of osmotic stress treatment, the E and leaf xylem water potentials of stressed plants unexpectedly increased. The increase in K_(leaf) and a partial recovery of K_(root) may have contributed to this process. The m RNA content of Zm PIP1;2 but not of the other three genes was up-regulated in roots at this time. In summary, the m RNA contents of these four Zm PIPs associated with K_(leaf) and K_(root) change in maize seedlings during short-term osmotic stress, especially for Zm PIP1;2 and Zm PIP2;5, which may help to further reveal the hydraulic resistance adjustment role of Zm PIPs.
基金financially supported by National Natural Science Foundation of China(31701449,31971968,31971899,31501332)National Key Research and Development Program of China(2016YFD 0100500,2016YFD0100300,2016YFD0100201-21,JFYS2016ZY03003792-01-21)+7 种基金China Postdoctoral Science Foundation(2019M661243)Postdoctoral Project of Northeast Agricultural University(NEAUBH-19002)EUCLEG(727312,2017YFE0111000)Natural Science Foundation of Heilongjiang Province(QC2017013)Special Financial Aid to Post-doctor Research Fellow in Heilongjiang(LBH-TZ1714)Heilongjiang Academy of Agricultural Sciences Funds(2019YYYF019)International Postdoctoral Exchange Fellowship Program of China Postdoctoral Council(20180004)Heilongjiang Funds for Distinguished Young Scientists(JC2016004,JC2017006)。
文摘In plants,glycerol-3-phosphate dehydrogenase(GPDH)catalyzes the interconversion of glycerol-3-phosphate(G3P)and dihydroxyacetone phosphate(DHAP)coupled to the reduction/oxidation of the nicotinamide adenine dinucleotide(NADH)pool,and plays a central role in glycerolipid metabolism and stress response.Previous studies have focused mainly on the NAD+-dependent GPDH isoforms,neglecting the role of flavin adenine dinucleotide(FAD)-dependent GPDHs.We isolated and characterized three mitochondrialtargeted FAD-GPDHs in soybean,of which one isoform(GmGPDH12)showed a significant transcriptional response to NaCl and mannitol treatments,suggesting the existence of a major FAD-GPDH isoform acting in soybean responses to salt and osmotic stress.An enzyme kinetic assay showed that the purified GmGPDH12 protein possessed the capacity to oxidize G3P to DHAP in the presence of FAD.Overexpression and RNA interference of GmGPDH12 in soybean hairy roots resulted in elevated tolerance and sensitivity to salt and osmotic stress,respectively.G3P contents were significantly lower in GmGPDH12-overexpressing hair roots and higher in knockdown hair roots,indicating that GmGPDH12 was essential for G3P catabolism.A significant perturbation in redox status of NADH,ascorbic acid(ASA)and glutathione(GSH)pools was observed in GmGPDH12-knockdown plants under stress conditions.The impaired redox balance was manifested by higher reactive oxygen species generation and consequent cell damage or death;however,overexpressing plants showed the opposite results for these traits.GmGPDH12 overexpression contributed to maintaining constant respiration rates under salt or osmotic stress by regulating mRNA levels of key mitochondrial respiratory enzymes.This study provides new evidence for the roles of mitochondria-localized GmGPDH12 in conferring resistance to salt or osmotic stress by maintaining cellular redox homeostasis,protecting cells and respiration from oxidative injury.
文摘Thirteen different inbred lines in relation to the type of grain and life cycles were characterized by testing for osmotic stress associated with salinity. The identification of tolerant genotypes would be an effective strategy to overcome the saline stress. Osmotic stress reduces immediately the expansion of the roots and young leaves which determine a reduction in the size of the plant. A completely randomized design was adopted to test seedlings under controlled conditions of light and temperature. Two treatments were used: 0 mM NaCl (as control) and 100 mM NaCl. After 15 days of complete salinization, the seedlings were harvested and several morphological traits were measured. The morphological traits of growth were leaf growth (Ar1, Ar2, Ar3 and Ar4), dry masses of shoot and root (SDM and RDM, respectively). Also, traits associated with water economy were registered: leaf water loss (LWL) and relative water content (RWC). The morphological traits were expressed in relative terms, while the traits associated with the economy of water were expressed in absolute terms. Uni and multivariate techniques were applied to identify genotypes with divergent behaviors to osmotic stress tolerance. Also, a Tolerance Index was employed to identify superior genotypes. Four clusters were obtained after applying a Cluster Analysis and Principal Component Analysis (PCA). The genotypes were compared to each other with a test of DMS. The results obtained with different statistical techniques converged. Some variables presented a differential weight classification of genotypes. The morphological traits like RDM, SDM, Ar3, Ar4 and Ar5 were the most discriminating. Tolerance Index allowed to classify genotypes, thus SC2 and AD3 lines were that reached highest value of the index and therefore would be tolerant lines, while AF3 and LP3 had a low index and were seen as sensible.
文摘Objectives: Exposing skin to moderate ionic osmotic stress (MIOS) triggers several biochemical responses. The objective of this work is to reveal the mechanism triggered by MIOS on the skin surface. Furthermore, this work aims to study the involvement of the Nrf2 (nuclear factor erythroid-2-related factor 2) pathway, activated by MIOS, and its beneficial effect in protecting skin against stress via the stimulation of phase II enzymes. Methods: HaCaT cells and human skin organ culture were exposed to Dead Sea Water (DSW) as MIOS inducers and the induction of internal ROS elevation, Nrf2 translocation, mRNA gene expressions of the phase II enzymes, heme-oxygenase 1 (HO1), and Catalase (CAT) were determined. Results: Skin exposure to MIOS increases Nrf2 translocation to the nucleus, leading to increased levels of ROS, HO1, and CAT. Furthermore, exposing skin to MIOS promotes protection against UVB-related risks. This is demonstrated by attenuation of the expression of biomarkers, related to UVB-induced damage, Caspase-3, IL-8, and IL-1β. Conclusions: Skin exposure to MIOS leads to the activation of Nrf2 skin defense pathway and, therefore, could present beneficial advantages to human skin health, as demonstrated on human skin models. The beneficial effects of MIOS, induced by DSW are significantly superior to eq. NaCl brine, suggests that MIOS protection of skin against stress is partially related to specific mineral combinations.
文摘The effects of osmotic stress on the ATPase activity, the contents of —SH group and conjugated polyamines in mitochondrial membrane from wheat seedling [Triticum aestivum L. cv. Yumai No.18(drought-tolerant) and cv. Yumai No.9(drought-sensitive)] roots were investigated. The results showed that ATPase activity and —SH group content decreased with polyethylene glycol(PEG) 6000(-0.55 MPa) treatment for 7 d, in concert with the decrease of the ratio of noncovalently conjugated spermidine(NCC-Spd)/noncovalently conjugated putrescine(NCC-Put) and increase of the covalently conjugated putrescine(CC-Put). Osmotic stress injury to Yangmai No.9 seedlings was alleviated greatly with 1 mmol/L exogenous spermidine(Spd), in concert with marked increases of the ratio of NCC-Spd/NCC-Put, —SH group contents and ATPase activity in mitochondrial membrane. Under osmotic stress, the concomitant treatment of Yumai No.18 seedlings with methylglyoxyl bis(guanylhydrazone) (MGBG), an inhibitor of S-adenosyl methionine decarboxylase(SAMDC), and phenanthrolin (o-Phen), an inhibitor of transglutaminase(TGase), caused a significant decrease of the ratio of NCC-Spd / NCC-Put, CC-Put contents, respectively, in concert with the marked decreases of ATPase activity, —SH group content and its tolerance to osmotic stress. All the results above suggested that osmotic stress tolerance of wheat seedlings was associated with the ATPase activity, the contents of —SH group, NCC-Spd and CC-Put in mitochondrial membrane.
文摘The osmotic pressure represented as a sign of plant tolerance or sensitive to salinity stress. In the following plants, the increase in OP seems to be a manner of defense mechanism to survive. OP increased in shoots of maize, shoot and root of wheat and cotton plants was concomitant with shoot soluble sugar, root soluble protein and shoot and root amino acids of maize plants. However, in wheat the increase in OP was related with increase of root soluble sugar and protein of shoots and roots. In cotton plants, the elevation of OP was run parallel with increase soluble sugar of shoots and roots, shoot soluble protein and root amino acids. The increase in OP was related with a marked and significant reduction in the water content of these plants. However, the decrease in OP of shoot and root of broad bean was related with the reduction of shoots and roots soluble sugar, protein and root amino acids of broad bean. While the OP becomes more or less unchanged in shoots and tended to decrease in root of parsley plants, this concomitant with unchanged trend in the shoots amino acids and reduction in root soluble sugar and root amino acids. Run with previous trend values of OP and metabolites of parsley plants were related with stable values in shoot water content and reduction in root water content. With GA<sub>3</sub> and kinetin treatments mostly increase the values OP which parallel with increase and soluble sugar, soluble protein and amino acids contents of shoots and roots of maize, wheat, cotton, broad bean and parsley plants with NaCl increasing. This related with increase water uptake by roots in these plants. The results indicated that kinetin had a more effective to shoot maize, both organs of wheat, broad bean and parsley plants in response to salinity stress while GA<sub>3</sub> was more effective on cotton plants especially at higher levels of salinity. Thus plants strategy differed in their tolerance to salinity stress according to their species and differed also according to the different organs of the same plants and kinetin treatment induced highly positively affect than GA<sub>3</sub> treatments.
文摘Leaf senescence is often caused by water deficit and the chimeric gene PSAG12-IPT is an auto-regulated gene delaying leaf senescence. Using in vitro leaf discs culture system, the changes of contents of chlorophylls, carotenoids, soluble protein and thiobarbituric acid reactive substance (TBARS) and antioxidant enzymes activities were investigated during leaf senescence of PSAGl2-IPT modified gerbera induced by osmotic stress compared with the control plant (wild type). Leaf discs were incubated in 20%, 40% (w/v) polyethylene glycol (PEG) 6 000 nutrient solution for 20 h under continuous light [130 μmol/(m2·s)]. The results showed that the contents of chlorophylls, carotenoids and soluble protein were decreased by osmotic stress with the decrease being more pronounced at 40% PEG, but that, at the same PEG concentration the decrease in the transgenic plants was significantly lower than that in the control plant. The activities of superoxide dismutase (SOD), catalases (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPX) and dehydroascorbate reductase (DHAR) were stimulated by PEG treatment. However, the increases were higher in PSAG12-IPT transgenic plants than in the control plants, particularly at 40% PEG treatment. Lipid peroxidation (TBARS content) was increased by PEG treatment with the increase being much lower in transgenic plant than in the control plant. It could be concluded that the increases in the activities of antioxidant enzymes including SOD, CAT, APX, GPX and DHAR were responsible for the delay of leaf senescence induced by osmotic stress.
基金supported by the National Natural Science Foundation of China (30471044)
文摘In order to investigate the effect of water channel blocker HgCl2 on the hydraulic resistance in roots of maize seedlings,a xylem pressure probe was used to monitor the changes in root xylem pressure in response to NaCl-or mannitol-induced osmotic stresses before and after the application of HgCl2.When the maize roots were subjected to 500 μmol L-1 HgCl2 in root bathing solution,not only a considerable decline in xylem pressure(increase in xylem tension) was observed,but the loss of responsiveness of the plant to both salt-and mannitol-induced osmotic stresses in terms of xylem pressure change was seen as well when the transpiration rate of the plant was not significantly changed.The results are similar but different from the reversed osmosis by the Fenton reaction in the internodes of Chara coralline,showing that the mechanisms of water transport across cell membrane in plant roots are far more complicated than expected.
文摘We investigated the influence of different levels of osmotic stress on growth and development in selected wild almond species(eight Prunus spp.) grown in vitro. The study, while endorsing the efficacy of in vitro screening of auxiliary buds of wild almond for osmotic stress tolerance, showed species variability in its response to osmotic stress. Osmotic stress reduced growth and development of all the species. However, the putative tolerant Prunus spp. showed better performance than the putative susceptible genotypes. On average there was an 80% decrease in shoot dry weight at-1.2 MPa. Reduction in shoot weight was more common in osmotic stress-susceptible species in the section labeled ‘Euamygdalus'. The tolerant Prunus species produced smaller changes in biochemical responses than the sensitive cultivars for malondialdehyde content, catalase activity, relative permeability of protoplast membranes, and net photosynthetic rate. The tolerant species maintained cell integrity better than drought sensitive species. Wild almond species in the section labeled ‘Spartioides'(Prunus arabica(Olivier) Neikle, Prunus glauca (Browicz) A.E. Murray, Prunus scoparia Spach) and ‘Lycioides'(Prunus lycioides Spach, Prunus reuteri Bossi. et Bushe) were best adapted to osmotic stress. Increase in chlorophyll concentration and leaf thickness under high osmotic stress can be considered as preliminary selection parameters for osmotic stress tolerance in Prunus spp. The study confirmed the efficacy of the in vitro method for screening of large number of genotypes for osmotic stress tolerance in wild almond species.
基金supported by grants from the National Natural Science Foundation of China(31972380,31170635).
文摘Clarifying the stress signal transduction pathway would be helpful for understanding the abiotic stress resistance mechanism in apple(Malus×domestica Borkh.)and could assist in the development of new varieties with high stress tolerance by genetic engineering.The key NAC transcription factor SND1,which is involved in the lignin biosynthesis process in apple,was functionally analyzed.The results of the stress treatments indicated that MdSND1 could be induced by salt,mannitol and ABA.Compared with wild-type GL-3 plants,MdSND1-overexpressing apple plants with greater antioxidant capacity and lignin were more resistant to salt and simulated osmotic stress,while RNAi plants were more vulnerable.Additionally,molecular experiments confirmed that MdSND1 could regulate the biosynthesis of lignin by activating the transcription of MdMYB46/83.Moreover,genes known to be involved in the stress signal transduction pathway(MdAREB1A,MdAREB1B,MdDREB2A,MdRD29A,and MdRD22)were screened for their close correlations with the expression of MdSND1 and the response to salt and osmotic stress.Multiple verification tests further demonstrated that MdSND1 could directly bind to these gene promoters and activate their transcription.The above results revealed that MdSND1 is directly involved in the regulation of lignin biosynthesis and the signal transduction pathway involved in the response to both salt and osmotic stress in apple.
基金The Qingdao Applied Basic Research Project under contract No.14-2-4-15-jchthe National Natural Science Foundation of China under contract No.31772828。
文摘Aquaporins(AQPs)are a family of integral membrane proteins that have been shown to be important for osmoregulation in many vertebrates.To identify potential stress resistance-related aqp genes in salinity adaptation of the roughskin sculpin Trachidermus fasciatus,we investigated the time-course expression dynamics of seven aquaporin genes(aqp1,4,7,8,10,11 and 12)in three osmoregulatory tissues(kidney,gill and intestine)and one metabolic tissue(liver).The fish were subjected to two different acute osmotic treatments(seawater-tofreshwater transfer respectively achieved in 1 h and 24 h,namely,E-acute and acute group).The expression profiling of the seven aqp genes were performed using quantitative real-time PCR(qRT-PCR).At the time of all sampling time points(0 h,12 h,24 h and 48 h),no expression of aqp4 was found in the gill,liver and intestine;no expression of aqp7 was found in the gill and liver.Significant differences of aqp expression were determined in the four target tissues,and the mRNA levels were largely variable among gene members and tissues.Similar patterns of the time-course expression were detected in most of the aqp genes in T.fasciatus between the two acute groups,except that only one gene(aqp12)in the kidney and three genes(aqp7,aqp8 and aqp10)in the intestine revealed different expression patterns.These results suggest that the expression response of aqp genes was similar under osmotic changes with different rates.
基金supported by the Province in Heilongjiang Outstanding Youth Science Fund(JC2017004)the National Natural Science Foundation of China(No.31370676)Heilongjiang Touyan Innovation Team Program(Tree Genetics and Breeding Innovation Team)。
文摘Trehalose is a non-reducing disaccharide with high stability and strong water absorption properties that can improve the resistance of organisms to various abiotic stresses.Trehalose-6-phosphate synthase(TPS)plays important roles in trehalose metabolism and signaling.In this study,the full-length cDNA of ThTPS was cloned from Tamarix hispida Willd.A phylogenetic tree including ThTPS and 11 AtTPS genes from Arabidopsis indicated that the ThTPS protein had a close evolutionary relationship with AtTPS7.However,the function of At TPS7 has not been determined.To analyze the abiotic stress tolerance function of ThTPS,the expression of ThTPS in T.hispida under salt and drought stress and JA,ABA and GA3 hormone stimulation was monitored by qRT-PCR.The results show that ThTPS expression was clearly induced by all five of these treatments at one or more times,and salt stress caused particularly strong induction of Th TPS in the roots of T.hispida.The ThTPS gene was transiently overexpressed in T.hispida.Both physiological indexes and staining results showed that ThTPS gene overexpression increased salt and osmotic stress tolerance in T.hispida.Overall,the Th TPS gene can respond to abiotic stresses such as salt and drought,and its overexpression can significantly improve salt and osmotic tolerance.These findings establish a foundation to better understand the responses of TPS genes to abiotic stress in plants.
文摘The aims of this study was to examine the effect of the osmotic (NaCl) water stress on, growth and accumulation of endogenous compatible solutes of Bacillus amyloliquefaciens and Microbacterium oleovorans, biocontrol agents against Fusarium verticillioides. Triptic soya broth media were modified ionically to 0.99;0.98;0.97 and 0.96 aw with NaCl. The endogenous contents of the intracellular compatible solutes glycine-betaine and ectoine were quantified. Cells grown under ionic solute stress showed accumulation of significant amounts of both amino acids in all treatments. The growth rate of F. verticillioides was decreased significantly by interaction with B. amyloliquefaciens and M. oleovorans physiologically adapted at 0.96 aw. This study have demonstrated the ability to synthesize betaine and ectoine under high-osmolality conditions of B. amyloliquefaciens and M. oleovorans cells. Such ecophysiological manipulation, especially to water stress, may increase the potential for biological control of F. verticillioides at field under wider aw conditions.
基金Supported by Key Program of Natural Science Foundation of Heilongjiang Province (ZJN03-5)
文摘PM2 gene (accession number: M80664) with high lysine content from soybean (Glycine max) was found in GenBank by changing three BLASTp parameters. Amino acid composition analysis of PM2 showed that Lys content was on the high level of 18.22%. Protein encoded by PM2 also belonged to the family of late embryogenesis abundant (LEA) proteins, which was considered that it had a strong relation with the abiotic stress resistance. In this experiment, PM2 gene was obtained from dry soybean seeds by RT-PCR, plant expression vector pEMTPM2 was constructed, and then transformed into tobacco by using agrobacterium-mediated method. Eight salt and drought tolerant lines were obtained from 31 differentiated lines. Real-time PCR showed that PM2 gene overexpressed in all four PCR positive lines with the osmotic stress resistance. These results confirmed that the overexpression of PM2 gene enhanced the osmotic stress resistance of transgenic tobacco.
基金supported by the National Key Tech-nologies R&D Program of China (2008BADA6B05)
文摘Changes in sucrose metabolism in response to salt (NaCl) and water (polyethylene glycol, PEG6000) iso-osmotic stresses were measured in tomato cultivar Liaoyuan Duoli (Solanum lycopersicum L.) and the objective was to provide a new evidence for the relationship between salt and osmotic stresses. The carbohydrate contents, as well as sucrose metabolizing enzymes activities and transcript levels were determined. The results indicated that soluble sugar and hexoses accumulated to higher levels and the contents of sucrose and starch were lower in mature fruit under the two stress treatments. Salt and water stresses can enhance the invertase and sucrose synthase activities of tomato fruit in a long period of time (45-60 days after anthesis), and elevate the expression of soluble acid invertase mRNA. It showed that two different stresses could also regulate the soluble acid invertase activity by controlling its gene expression. The activity of sucrose synthase was linked to the changes in soluble sugar levels but not with transcript levels. The effects of salt and water stress treatments on sucrose phosphate synthase activities were weak.
