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Sample records for increases salt tolerance

  1. Azetidine-2-carboxylic acid resistant mutants of Arabidopsis thaliana with increased salt tolerance

    SciTech Connect

    Lehle, F.R.; Murphy, M.A.; Khan, R.A. )

    1989-04-01

    Nineteen mutant Arabidopsis families resistant to the proline analog azetidine-2-carboxylic acid (ACA) were characterized in terms of NaCl tolerance and proline content. Mutants were selected from about 64,000 progeny of about 16,000 self-pollinated Columbia parents which had been mutated with ethyl methane sulfonate during seed imbibition. Selections were performed during seed germination on aseptic agar medium containing 0.2 to 0.25 mM ACA. Nineteen mutant families, 12 clearly independent, retained resistance to ACA in the M{sub 4} generation. Based on germination on 150 mM NaCl, 13 of the mutant families were more tolerant than the wild type. Two mutants of intermediate resistance to ACA were markedly more salt tolerant than the others. Four mutant families appeared to overproduce proline. Of these, only 3 showed slight increases in salt tolerance.

  2. Salt tolerant plants increase nitrogen removal from biofiltration systems affected by saline stormwater.

    PubMed

    Szota, Christopher; Farrell, Claire; Livesley, Stephen J; Fletcher, Tim D

    2015-10-15

    Biofiltration systems are used in urban areas to reduce the concentration and load of nutrient pollutants and heavy metals entering waterways through stormwater runoff. Biofilters can, however be exposed to salt water, through intrusion of seawater in coastal areas which could decrease their ability to intercept and retain pollutants. We measured the effect of adding saline stormwater on pollutant removal by six monocotyledonous species with different levels of salt-tolerance. Carex appressa, Carex bichenoviana, Ficinia nodosa, Gahnia filum, Juncus kraussii and Juncus usitatus were exposed to six concentrations of saline stormwater, equivalent to electrical conductivity readings of: 0.09, 2.3, 5.5, 10.4, 20.0 and 37.6 mS cm(-1). Salt-sensitive species: C. appressa, C. bichenoviana and J. usitatus did not survive ≥10.4 mS cm(-1), removing their ability to take up nitrogen (N). Salt-tolerant species, such as F. nodosa and J. kraussii, maintained N-removal even at the highest salt concentration. However, their levels of water stress and stomatal conductance suggest that N-removal would not be sustained at concentrations ≥10.4 mS cm(-1). Increasing salt concentration indirectly increased phosphorus (P) removal, by converting dissolved forms of P to particulate forms which were retained by filter media. Salt concentrations ≥10 mS cm(-1) also reduced removal efficiency of zinc, manganese and cadmium, but increased removal of iron and lead, regardless of plant species. Our results suggest that biofiltration systems exposed to saline stormwater ≤10 mS cm(-1) can only maintain N-removal when planted with salt-tolerant species, while P removal and immobilisation of heavy metals is less affected by species selection. PMID:26150068

  3. Increasing cyclic electron flow is related to Na+ sequestration into vacuoles for salt tolerance in soybean.

    PubMed

    He, Yi; Fu, Junliang; Yu, Chenliang; Wang, Xiaoman; Jiang, Qinsu; Hong, Jian; Lu, Kaixing; Xue, Gangping; Yan, Chengqi; James, Andrew; Xu, Ligen; Chen, Jianping; Jiang, Dean

    2015-11-01

    In land plants, the NAD(P)H dehydrogenase (NDH) complex reduces plastoquinones and drives cyclic electron flow (CEF) around PSI. It also produces extra ATP for photosynthesis and improves plant fitness under conditions of abiotic environmental stress. To elucidate the role of CEF in salt tolerance of the photosynthetic apparatus, Na(+) concentration, chlorophyll fluorescence, and expression of NDH B and H subunits, as well as of genes related to cellular and vacuolar Na(+) transport, were monitored. The salt-tolerant Glycine max (soybean) variety S111-9 exhibited much higher CEF activity and ATP accumulation in light than did the salt-sensitive variety Melrose, but similar leaf Na(+) concentrations under salt stress. In S111-9 plants, ndhB and ndhH were highly up-regulated under salt stress and their corresponding proteins were maintained at high levels or increased significantly. Under salt stress, S111-9 plants accumulated Na(+) in the vacuole, but Melrose plants accumulated Na(+) in the chloroplast. Compared with Melrose, S111-9 plants also showed higher expression of some genes associated with Na(+) transport into the vacuole and/or cell, such as genes encoding components of the CBL10 (calcineurin B-like protein 10)-CIPK24 (CBL-interacting protein kinase 24)-NHX (Na(+)/H(+) antiporter) and CBL4 (calcineurin B-like protein 4)-CIPK24-SOS1 (salt overly sensitive 1) complexes. Based on the findings, it is proposed that enhanced NDH-dependent CEF supplies extra ATP used to sequester Na(+) in the vacuole. This reveals an important mechanism for salt tolerance in soybean and provides new insights into plant resistance to salt stress. PMID:26276865

  4. Increasing cyclic electron flow is related to Na+ sequestration into vacuoles for salt tolerance in soybean

    PubMed Central

    He, Yi; Fu, Junliang; Yu, Chenliang; Wang, Xiaoman; Jiang, Qinsu; Hong, Jian; Lu, Kaixing; Xue, Gangping; Yan, Chengqi; James, Andrew; Xu, Ligen; Chen, Jianping; Jiang, Dean

    2015-01-01

    In land plants, the NAD(P)H dehydrogenase (NDH) complex reduces plastoquinones and drives cyclic electron flow (CEF) around PSI. It also produces extra ATP for photosynthesis and improves plant fitness under conditions of abiotic environmental stress. To elucidate the role of CEF in salt tolerance of the photosynthetic apparatus, Na+ concentration, chlorophyll fluorescence, and expression of NDH B and H subunits, as well as of genes related to cellular and vacuolar Na+ transport, were monitored. The salt-tolerant Glycine max (soybean) variety S111-9 exhibited much higher CEF activity and ATP accumulation in light than did the salt-sensitive variety Melrose, but similar leaf Na+ concentrations under salt stress. In S111-9 plants, ndhB and ndhH were highly up-regulated under salt stress and their corresponding proteins were maintained at high levels or increased significantly. Under salt stress, S111-9 plants accumulated Na+ in the vacuole, but Melrose plants accumulated Na+ in the chloroplast. Compared with Melrose, S111-9 plants also showed higher expression of some genes associated with Na+ transport into the vacuole and/or cell, such as genes encoding components of the CBL10 (calcineurin B-like protein 10)–CIPK24 (CBL-interacting protein kinase 24)–NHX (Na+/H+ antiporter) and CBL4 (calcineurin B-like protein 4)–CIPK24–SOS1 (salt overly sensitive 1) complexes. Based on the findings, it is proposed that enhanced NDH-dependent CEF supplies extra ATP used to sequester Na+ in the vacuole. This reveals an important mechanism for salt tolerance in soybean and provides new insights into plant resistance to salt stress. PMID:26276865

  5. Salt tolerance of Beta macrocarpa is associated with efficient osmotic adjustment and increased apoplastic water content.

    PubMed

    Hamouda, I; Badri, M; Mejri, M; Cruz, C; Siddique, K H M; Hessini, K

    2016-05-01

    The chenopod Beta macrocarpa Guss (wild Swiss chard) is known for its salt tolerance, but the mechanisms involved are still debated. In order to elucidate the processes involved, we grew wild Swiss chard exposed to three salinity levels (0, 100 and 200 mm NaCl) for 45 days, and determined several physiological parameters at the end of this time. All plants survived despite reductions in growth, photosynthesis and stomatal conductance in plants exposed to salinity (100 and 200 mm NaCl). As expected, the negative effects of salinity were more pronounced at 200 mm than at 100 mm NaCl: (i) leaf apoplastic water content was maintained or increased despite a significant reduction in leaf water potential, revealing the halophytic character of B. macrocarpa; (ii) osmotic adjustment occurred, which presumably enhanced the driving force for water extraction from soil, and avoided toxic build up of Na(+) and Cl(-) in the mesophyll apoplast of leaves. Osmotic adjustment mainly occurred through accumulation of inorganic ions and to a lesser extent soluble sugars; proline was not implicated in osmotic adjustment. Overall, two important mechanisms of salt tolerance in B. macrocarpa were identified: osmotic and apoplastic water adjustment. PMID:26588061

  6. Over-expression of a novel JAZ family gene from Glycine soja, increases salt and alkali stress tolerance

    SciTech Connect

    Zhu, Dan; Cai, Hua; Luo, Xiao; Bai, Xi; Deyholos, Michael K.; Chen, Qin; Chen, Chao; Ji, Wei; Zhu, Yanming

    2012-09-21

    Highlights: Black-Right-Pointing-Pointer We isolated and characterized a novel JAZ family gene, GsJAZ2, from Glycine soja. Black-Right-Pointing-Pointer Overexpression of GsJAZ2 enhanced plant tolerance to salt and alkali stress. Black-Right-Pointing-Pointer The transcriptions of stress marker genes were higher in GsJAZ2 overexpression lines. Black-Right-Pointing-Pointer GsJAZ2 was localized to nucleus. -- Abstract: Salt and alkali stress are two of the main environmental factors limiting crop production. Recent discoveries show that the JAZ family encodes plant-specific genes involved in jasmonate signaling. However, there is only limited information about this gene family in abiotic stress response, and in wild soybean (Glycine soja), which is a species noted for its tolerance to alkali and salinity. Here, we isolated and characterized a novel JAZ family gene, GsJAZ2, from G. soja. Transcript abundance of GsJAZ2 increased following exposure to salt, alkali, cold and drought. Over-expression of GsJAZ2 in Arabidopsis resulted in enhanced plant tolerance to salt and alkali stress. The expression levels of some alkali stress response and stress-inducible marker genes were significantly higher in the GsJAZ2 overexpression lines as compared to wild-type plants. Subcellular localization studies using a GFP fusion protein showed that GsJAZ2 was localized to the nucleus. These results suggest that the newly isolated wild soybean GsJAZ2 is a positive regulator of plant salt and alkali stress tolerance.

  7. Macroevolutionary patterns of salt tolerance in angiosperms

    PubMed Central

    Bromham, Lindell

    2015-01-01

    Background Halophytes are rare, with only 0·25 % of angiosperm species able to complete their life cycle in saline conditions. This could be interpreted as evidence that salt tolerance is difficult to evolve. However, consideration of the phylogenetic distribution of halophytes paints a different picture: salt tolerance has evolved independently in many different lineages, and halophytes are widely distributed across angiosperm families. In this Viewpoint, I will consider what phylogenetic analysis of halophytes can tell us about the macroevolution of salt tolerance. Hypothesis Phylogenetic analyses of salt tolerance have shown contrasting patterns in different families. In some families, such as chenopods, salt tolerance evolved early in the lineage and has been retained in many lineages. But in other families, including grasses, there have been a surprisingly large number of independent origins of salt tolerance, most of which are relatively recent and result in only one or a few salt-tolerant species. This pattern of many recent origins implies either a high transition rate (salt tolerance is gained and lost often) or a high extinction rate (salt-tolerant lineages do not tend to persist over macroevolutionary timescales). While salt tolerance can evolve in a wide range of genetic backgrounds, some lineages are more likely to produce halophytes than others. This may be due to enabling traits that act as stepping stones to developing salt tolerance. The ability to tolerate environmental salt may increase tolerance of other stresses or vice versa. Conclusions Phylogenetic analyses suggest that enabling traits and cross-tolerances may make some lineages more likely to adapt to increasing salinization, a finding that may prove useful in assessing the probable impact of rapid environmental change on vegetation communities, and in selecting taxa to develop for use in landscape rehabilitation and agriculture. PMID:25452251

  8. A chimeric vacuolar Na(+)/H(+) antiporter gene evolved by DNA family shuffling confers increased salt tolerance in yeast.

    PubMed

    Wu, Guangxia; Wang, Gang; Ji, Jing; Li, Yong; Gao, Hailing; Wu, Jiang; Guan, Wenzhu

    2015-06-10

    The vacuolar Na(+)/H(+) antiporter plays an important role in maintaining ionic homeostasis and the osmotic balance of the cell with the environment by sequestering excessive cytoplasmic Na(+) into the vacuole. However, the relatively low Na(+)/H(+) exchange efficiency of the identified Na(+)/H(+) antiporter could limit its application in the molecular breeding of salt tolerant crops. In this study, DNA family shuffling was used to create chimeric Na(+)/H(+) antiporters with improved transport activity. Two homologous Na(+)/H(+) antiporters from halophytes Salicornia europaea (SeNHX1) and Suaeda salsa (SsNHX1) were shuffled to generate a diverse gene library. Using a high-throughput screening system of yeast complementation, a novel chimeric protein SseNHX1 carrying 12 crossover positions and 2 point mutations at amino acid level was selected. Expression of SseNHX1 in yeast mutant exhibited approximately 46% and 22% higher salt tolerance ability in yeast growth test than that of SsNHX1and SeNHX1, respectively. Measurements of the ion contents demonstrated that SseNHX1 protein in yeast cells accumulated more Na(+) and slightly more K(+) than the parental proteins did. Furthermore, this chimera also conferred increased tolerance to LiCl and a similar tolerance to hygromycin B compared with the parental proteins in yeast. PMID:25784157

  9. Increased Salt and Drought Tolerance by D-Ononitol Production in Transgenic Nicotiana tabacum L.

    PubMed Central

    Sheveleva, E.; Chmara, W.; Bohnert, H. J.; Jensen, R. G.

    1997-01-01

    A cDNA encoding myo-inositol O-methyltransferase (IMT1) has been transferred into Nicotiana tabacum cultivar SR1. During drought and salt stress, transformants (I5A) accumulated the methylated inositol D-ononitol in amounts exceeding 35 [mu]mol g-1 fresh weight In I5A, photosynthetic CO2 fixation was inhibited less during salt stress and drought, and the plants recovered faster than wild type. One day after rewatering drought-stressed plants, I5A photosynthesis had recovered 75% versus 57% recovery with cultivar SR1 plants. After 2.5 weeks of 250 mM NaCl in hydroponic solution, I5A fixed 4.9 [plus or minus] 1.4 [mu]mol CO2 m-2 s-1, whereas SR1 fixed 2.5 [plus or minus] 0.6 [mu]mol CO2 m-2 s-1. myo-Inositol, the substrate for IMT1, increases in tobacco under stress. Preconditioning of I5A plants in 50 mM NaCl increased D-ononitol amounts and resulted in increased protection when the plants were stressed subsequently with 150 mM NaCl. Pro, Suc, Fru, and Glc showed substantial diurnal fluctuations in amounts, but D-ononitol did not. Plant transformation resulting in stress-inducible, stable solute accumulation appears to provide better protection under drought and salt-stress conditions than strategies using osmotic adjustment by metabolites that are constitutively present. PMID:12223867

  10. Plant salt-tolerance mechanisms

    DOE PAGESBeta

    Deinlein, Ulrich; Stephan, Aaron B.; Horie, Tomoaki; Luo, Wei; Xu, Guohua; Schroeder, Julian I.

    2014-06-01

    Crop performance is severely affected by high salt concentrations in soils. To engineer more salt-tolerant plants it is crucial to unravel the key components of the plant salt-tolerance network. Here we review our understanding of the core salt-tolerance mechanisms in plants. Recent studies have shown that stress sensing and signaling components can play important roles in regulating the plant salinity stress response. We also review key Na+ transport and detoxification pathways and the impact of epigenetic chromatin modifications on salinity tolerance. In addition, we discuss the progress that has been made towards engineering salt tolerance in crops, including marker-assisted selectionmore » and gene stacking techniques. We also identify key open questions that remain to be addressed in the future.« less

  11. Plant salt-tolerance mechanisms

    SciTech Connect

    Deinlein, Ulrich; Stephan, Aaron B.; Horie, Tomoaki; Luo, Wei; Xu, Guohua; Schroeder, Julian I.

    2014-06-01

    Crop performance is severely affected by high salt concentrations in soils. To engineer more salt-tolerant plants it is crucial to unravel the key components of the plant salt-tolerance network. Here we review our understanding of the core salt-tolerance mechanisms in plants. Recent studies have shown that stress sensing and signaling components can play important roles in regulating the plant salinity stress response. We also review key Na+ transport and detoxification pathways and the impact of epigenetic chromatin modifications on salinity tolerance. In addition, we discuss the progress that has been made towards engineering salt tolerance in crops, including marker-assisted selection and gene stacking techniques. We also identify key open questions that remain to be addressed in the future.

  12. Salt-tolerant rootstock increases yield of pepper under salinity through maintenance of photosynthetic performance and sinks strength.

    PubMed

    Penella, Consuelo; Landi, Marco; Guidi, Lucia; Nebauer, Sergio G; Pellegrini, Elisa; San Bautista, Alberto; Remorini, Damiano; Nali, Cristina; López-Galarza, Salvador; Calatayud, Angeles

    2016-04-01

    The performance of a salt-tolerant pepper (Capsicum annuum L.) accession (A25) utilized as a rootstock was assessed in two experiments. In a first field experiment under natural salinity conditions, we observed a larger amount of marketable fruit (+75%) and lower Blossom-end Root incidence (-31%) in commercial pepper cultivar Adige (A) grafted onto A25 (A/A25) when compared with ungrafted plants. In order to understand this behavior a second greenhouse experiment was conducted to determine growth, mineral partitioning, gas exchange and chlorophyll a fluorescence parameters, antioxidant systems and proline content in A and A/A25 plants under salinity conditions (80 mM NaCl for 14 days). Salt stress induced significantly stunted growth of A plants (-40.6% of leaf dry weight) compared to the control conditions, while no alterations were observed in A/A25 at the end of the experiment. Accumulation of Na(+) and Cl(-) in leaves and roots was similar in either grafted or ungrafted plants. Despite the activation of protective mechanisms (increment of superoxide dismutase, catalase, ascorbate peroxidase activity and non-photochemical quenching), A plants showed severely reduced photosynthetic CO2 assimilation (-45.6% of AN390) and substantial buildup of malondialdehyde (MDA) by-product, suggesting the inability to counteract salt-triggered damage. In contrast, A/A25 plants, which had a constitutive enhanced root apparatus, were able to maintain the shoot and root growth under salinity conditions by supporting the maintained photosynthetic performance. No increases in catalase and ascorbate peroxidase activities were observed in response to salinity, and MDA levels increased only slightly; indicating that alleviation of oxidative stress did not occur in A/A25 plants. In these plants the increased proline levels could protect enzymatic stability from salt-triggered damage, preserving the photosynthetic performance. The results could indicate that salt stress was vanished by

  13. Plant salt tolerance: adaptations in halophytes

    PubMed Central

    Flowers, Timothy J.; Colmer, Timothy D.

    2015-01-01

    Background Most of the water on Earth is seawater, each kilogram of which contains about 35 g of salts, and yet most plants cannot grow in this solution; less than 0·2 % of species can develop and reproduce with repeated exposure to seawater. These ‘extremophiles’ are called halophytes. Scope Improved knowledge of halophytes is of importance to understanding our natural world and to enable the use of some of these fascinating plants in land re-vegetation, as forages for livestock, and to develop salt-tolerant crops. In this Preface to a Special Issue on halophytes and saline adaptations, the evolution of salt tolerance in halophytes, their life-history traits and progress in understanding the molecular, biochemical and physiological mechanisms contributing to salt tolerance are summarized. In particular, cellular processes that underpin the ability of halophytes to tolerate high tissue concentrations of Na+ and Cl−, including regulation of membrane transport, their ability to synthesize compatible solutes and to deal with reactive oxygen species, are highlighted. Interacting stress factors in addition to salinity, such as heavy metals and flooding, are also topics gaining increased attention in the search to understand the biology of halophytes. Conclusions Halophytes will play increasingly important roles as models for understanding plant salt tolerance, as genetic resources contributing towards the goal of improvement of salt tolerance in some crops, for re-vegetation of saline lands, and as ‘niche crops’ in their own right for landscapes with saline soils. PMID:25844430

  14. The expression of the Saccharomyces cerevisiae HAL1 gene increases salt tolerance in transgenic watermelon [Citrullus lanatus (Thunb.) Matsun. & Nakai.].

    PubMed

    Ellul, P; Ríos, G; Atarés, A; Roig, L A; Serrano, R; Moreno, V

    2003-08-01

    An optimised Agrobacterium-mediated gene transfer protocol was developed in order to obtain watermelon transgenic plants [Citrullus lanatus (Thunb.) Matsun. & Nakai.]. Transformation efficiencies ranged from 2.8% to 5.3%, depending on the cultivar. The method was applied to obtain genetically engineered watermelon plants expressing the Saccharomyces cerevisiae HAL1 gene related to salt tolerance. In order to enhance its constitutive expression in plants, the HAL1 gene was cloned in a pBiN19 plasmid under control of the 35S promoter with a double enhancer sequence from the cauliflower mosaic virus and the RNA4 leader sequence of the alfalfa mosaic virus. This vector was introduced into Agrobacterium tumefaciens strain LBA4404 for further inoculation of watermelon half-cotyledon explants. The introduction of both the neomycin phosphotransferase II and HAL1 genes was assessed in primary transformants (TG1) by polymerase chain reaction analysis and Southern hybridisation. The expression of the HAL1 gene was determined by Northern analysis, and the diploid level of transgenic plants was confirmed by flow cytometry. The presence of the selectable marker gene in the expected Mendelian ratios was demonstrated in TG2 progenies. The TG2 kanamycin-resistant plantlets elongated better and produced new roots and leaves in culture media supplemented with NaCl compared with the control. Salt tolerance was confirmed in a semi-hydroponic system (EC=6 dS m(-1)) on the basis of the higher growth performance of homozygous TG3 lines with respect to their respective azygous control lines without the transgene. The halotolerance observed confirmed the inheritance of the trait and supports the potential usefulness of the HAL1 gene of S. cerevisiae as a molecular tool for genetic engineering of salt-stress protection in other crop species. PMID:12783167

  15. Plant salt tolerance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many factors have led to increased interest in using recycled wastewaters to irrigate agronomic and horticultural crops as well as plants in ornamental landscapes. One major driving force is the uncertainty of the allocation and dependability of good quality water in the future as competition among...

  16. Reducing Cytoplasmic Polyamine Oxidase Activity in Arabidopsis Increases Salt and Drought Tolerance by Reducing Reactive Oxygen Species Production and Increasing Defense Gene Expression

    PubMed Central

    Sagor, G. H. M.; Zhang, Siyuan; Kojima, Seiji; Simm, Stefan; Berberich, Thomas; Kusano, Tomonobu

    2016-01-01

    The link between polyamine oxidases (PAOs), which function in polyamine catabolism, and stress responses remains elusive. Here, we address this issue using Arabidopsis pao mutants in which the expression of the five PAO genes is knocked-out or knocked-down. As the five single pao mutants and wild type (WT) showed similar response to salt stress, we tried to generate the mutants that have either the cytoplasmic PAO pathway (pao1 pao5) or the peroxisomal PAO pathway (pao2 pao3 pao4) silenced. However, the latter triple mutant was not obtained. Thus, in this study, we used two double mutants, pao1 pao5 and pao2 pao4. Of interest, pao1 pao5 mutant was NaCl- and drought-tolerant, whereas pao2 pao4 showed similar sensitivity to those stresses as WT. To reveal the underlying mechanism of salt tolerance, further analyses were performed. Na uptake of the mutant (pao1 pao5) decreased to 75% of WT. PAO activity of the mutant was reduced to 62% of WT. The content of reactive oxygen species (ROS) such as hydrogen peroxide, a reaction product of PAO action, and superoxide anion in the mutant became 81 and 72% of the levels in WT upon salt treatment. The mutant contained 2.8-fold higher thermospermine compared to WT. Moreover, the mutant induced the genes of salt overly sensitive-, abscisic acid (ABA)-dependent- and ABA-independent- pathways more strongly than WT upon salt treatment. The results suggest that the Arabidopsis plant silencing cytoplasmic PAOs shows salinity tolerance by reducing ROS production and strongly inducing subsets of stress-responsive genes under stress conditions. PMID:26973665

  17. Reducing Cytoplasmic Polyamine Oxidase Activity in Arabidopsis Increases Salt and Drought Tolerance by Reducing Reactive Oxygen Species Production and Increasing Defense Gene Expression.

    PubMed

    Sagor, G H M; Zhang, Siyuan; Kojima, Seiji; Simm, Stefan; Berberich, Thomas; Kusano, Tomonobu

    2016-01-01

    The link between polyamine oxidases (PAOs), which function in polyamine catabolism, and stress responses remains elusive. Here, we address this issue using Arabidopsis pao mutants in which the expression of the five PAO genes is knocked-out or knocked-down. As the five single pao mutants and wild type (WT) showed similar response to salt stress, we tried to generate the mutants that have either the cytoplasmic PAO pathway (pao1 pao5) or the peroxisomal PAO pathway (pao2 pao3 pao4) silenced. However, the latter triple mutant was not obtained. Thus, in this study, we used two double mutants, pao1 pao5 and pao2 pao4. Of interest, pao1 pao5 mutant was NaCl- and drought-tolerant, whereas pao2 pao4 showed similar sensitivity to those stresses as WT. To reveal the underlying mechanism of salt tolerance, further analyses were performed. Na uptake of the mutant (pao1 pao5) decreased to 75% of WT. PAO activity of the mutant was reduced to 62% of WT. The content of reactive oxygen species (ROS) such as hydrogen peroxide, a reaction product of PAO action, and superoxide anion in the mutant became 81 and 72% of the levels in WT upon salt treatment. The mutant contained 2.8-fold higher thermospermine compared to WT. Moreover, the mutant induced the genes of salt overly sensitive-, abscisic acid (ABA)-dependent- and ABA-independent- pathways more strongly than WT upon salt treatment. The results suggest that the Arabidopsis plant silencing cytoplasmic PAOs shows salinity tolerance by reducing ROS production and strongly inducing subsets of stress-responsive genes under stress conditions. PMID:26973665

  18. Characterization of salt-tolerant β-glucosidase with increased thermostability under high salinity conditions from Bacillus sp. SJ-10 isolated from jeotgal, a traditional Korean fermented seafood.

    PubMed

    Lee, Jong Min; Kim, Yu-Ri; Kim, Joong Kyun; Jeong, Gwi-Taek; Ha, Jeong-Chul; Kong, In-Soo

    2015-07-01

    The β-glucosidase gene, bglC, was cloned from Bacillus sp. SJ-10 isolated from the squid jeotgal. Recombinant BglC protein overexpression was induced in Escherichia coli. The optimal pH and temperature of the enzyme, using p-nitrophenyl-β-D-glucopyranoside (pNPβGlc) as a substrate, were pH 6 and 40 °C, respectively. Enzymatic activity increased by 3.3- and 3.5-fold in the presence of 15% NaCl and KCl, respectively. Furthermore, enzyme thermostability improved in the presence of NaCl or KCl. At 45 °C in the presence of salts, the enzyme was stable for 2 h and maintained 80% activity. In the absence of salts, BglC completely lost activity after 110 min at 45 °C. Comparison of the kinetic parameters at various salt concentrations revealed that BglC had approximately 1.5- and 1.2-fold higher affinity and hydrolyzed pNPβGlc 1.9- and 2.1-fold faster in the presence of 15% NaCl and KCl, respectively. Additionally, the Gibb's free energy for denaturation was higher in the presence of 15% salt than in the absence of salt at 45 and 50 °C. Since enzymatic activity and thermostability were enhanced under high salinity conditions, BglC is an ideal salt-tolerant enzyme for further research and industrial applications. PMID:25682105

  19. The bioenergetics of salt tolerance

    SciTech Connect

    Packer, L.

    1991-01-01

    The aims of this project was to try to understand the adaptive mechanisms that organisms develop in order to respond to a sudden transformation in their environment to a salt shock.'' To study this problem we used a fresh water oxygenic photosynthetic cyanobacterium known as Synecoccus 6311. This organism suffers injury after this sudden exposure to high concentrations of sodium chloride equivalent to or even higher than that in sea water. Yet they are able to re-establish their photosynthetic activity which is partially injured and return to virtually normal growth rates. Identification of the temporal sequence of changes involved in adaptation to this stress was the rationale. Indeed this project employed a wide variety of biochemical and biophysical methods, including electron spin resonance techniques and nuclear magnetic resonance to study the bioenergetics and transport mechanisms, growth and energy changes in these organisms and how the structural components of the cells changed in response to adaptation to growth at high salinity. The problem has relevance for higher plants because most of the arable farmland in the world is already under use and that which is not used is usually in salite environments. Hence, understanding basic mechanisms of salt tolerance is a fundamental biological problem with great applications for bioproductivity and agriculture.

  20. The bioenergetics of salt tolerance

    SciTech Connect

    Packer, L.

    1991-01-01

    The aim of this project was to try to understand the adaptive mechanisms that organisms develop in order to respond to a sudden transformation in their environment to a salt shock.'' To study this problem we used a fresh water oxygenic photosynthetic cyanobacterium known as Synecoccus 6311. This organism suffers injury after this sudden exposure to high concentrations of sodium chloride equivalent to or even higher than that in sea water. Yet they are able to re-establish their photosynthetic activity which is partially injured and return to virtually normal growth rates. Identification of the temporal sequence of changes involved in adaptation to this stress was the rationale. Indeed this project employed a wide variety of biochemical and biophysical methods, including electron spin resonance techniques and nuclear magnetic resonance to study the bioenergetics and transport mechanisms, growth and energy changes in these organisms and how the structural components of the cells changed in response to adaptation to growth at high salinity. The problem has relevance for higher plants because most of the arable farmland in the work is already under use and that which is not used is usually in salite environments. Hence, understanding basic mechanisms of salt tolerance is a fundamental biological problem with great applications for bioproductivity and agriculture. 18 refs.

  1. Increased tolerance to salt stress in OPDA-deficient rice ALLENE OXIDE CYCLASE mutants is linked to an increased ROS-scavenging activity

    PubMed Central

    Hazman, Mohamed; Hause, Bettina; Eiche, Elisabeth; Nick, Peter; Riemann, Michael

    2015-01-01

    Salinity stress represents a global constraint for rice, the most important staple food worldwide. Therefore the role of the central stress signal jasmonate for the salt response was analysed in rice comparing the responses to salt stress for two jasmonic acid (JA) biosynthesis rice mutants (cpm2 and hebiba) impaired in the function of ALLENE OXIDE CYCLASE (AOC) and their wild type. The aoc mutants were less sensitive to salt stress. Interestingly, both mutants accumulated smaller amounts of Na+ ions in their leaves, and showed better scavenging of reactive oxygen species (ROS) under salt stress. Leaves of the wild type and JA mutants accumulated similar levels of abscisic acid (ABA) under stress conditions, and the levels of JA and its amino acid conjugate, JA–isoleucine (JA-Ile), showed only subtle alterations in the wild type. In contrast, the wild type responded to salt stress by strong induction of the JA precursor 12-oxophytodienoic acid (OPDA), which was not observed in the mutants. Transcript levels of representative salinity-induced genes were induced less in the JA mutants. The absence of 12-OPDA in the mutants correlated not only with a generally increased ROS-scavenging activity, but also with the higher activity of specific enzymes in the antioxidative pathway, such as glutathione S-transferase, and fewer symptoms of damage as, for example, indicated by lower levels of malondialdehyde. The data are interpreted in a model where the absence of OPDA enhanced the antioxidative power in mutant leaves. PMID:25873666

  2. Overexpression of soybean miR172c confers tolerance to water deficit and salt stress, but increases ABA sensitivity in transgenic Arabidopsis thaliana.

    PubMed

    Li, Wenbin; Wang, Tao; Zhang, Yuhang; Li, Yongguang

    2016-01-01

    MiRNAs play crucial roles in many aspects of plant development and the response to the environment. The miR172 family has been shown to participate in the control of flowering time and the response to abiotic stress. This family regulates the expression of APETALA2 (AP2)-like transcription factors in Arabidopsis. In the present study, soybean (Glycine max L. Merr.) miR172c, a member of the miR172 family, and its target gene were investigated for abiotic stress responses in transgenic Arabidopsis. gma-miR172c was induced by abscisic acid (ABA) treatments and abiotic stresses, including salt and water deficit. 5'-RACE (5'-rapid amplification of cDNA ends) assays indicated that miR172c directed Glyma01g39520 mRNA cleavage in soybeans. Overexpression of gma-miR172c in Arabidopsis resulted in reduced leaf water loss and increased survival rate under stress conditions. Meanwhile, the root length, germination rate, and cotyledon greening of transgenic plants were improved during both high salt and water deficit conditions. In addition, transgenic plants exhibited hypersensitivity to ABA during both the seed germination and post-germination seedling growth stages. Stress-related physiological indicators and the expression of stress/ABA-responsive genes were affected by abiotic treatments. The overexpression of gma-miR172c in Arabidopsis promoted earlier flowering compared with the wild type through modulation of the expression of flowering genes, such as FT and LFY during long days, especially under drought conditions. Glyma01g39520 weakened ABA sensitivity and reduced the tolerance to drought stress in the snz mutant of Arabidopsis by reducing the expression of ABI3 and ABI5. Overall, the present results demonstrate that gma-miR172c confers water deficit and salt tolerance but increased ABA sensitivity by regulating Glyma01g39520, which also accelerates flowering under abiotic stresses. PMID:26466661

  3. Molten salt electrolyte battery cell with overcharge tolerance

    DOEpatents

    Kaun, Thomas D.; Nelson, Paul A.

    1989-01-01

    A molten salt electrolyte battery having an increased overcharge tolerance employs a negative electrode with two lithium alloy phases of different electrochemical potential, one of which allows self-discharge rates which permits battery cell equalization.

  4. Does salt increase thirst?

    PubMed

    Leshem, Micah

    2015-02-01

    Our diet is believed to be overly rich in sodium, and it is commonly believed that sodium intake increases drinking. Hence the concern of a possible contribution of dietary sodium to beverage intake which in turn may contribute to obesity and ill health. Here we examine whether voluntary, acute intake of a sodium load, as occurs in routine eating and snacking, increases thirst and drinking. We find that after ingesting 3.5 or 4.4 g NaCl (men) and 1.9 or 3.7 g (women) on nuts during 15 minutes, there is no increase in thirst or drinking of freely available water in the following 2 h compared with eating similar amounts of sugared or unflavored nuts. This suggests that routine ingestion of boluses of salt (~30-40% of daily intake for men, ~ 20-40% for women) does not increase drinking. Methodological concerns such as about nuts as vehicle for sodium suggest further research to establish the generalizability of this unexpected result. PMID:25447020

  5. Salt Tolerance of Desorption Electrospray Ionization (DESI)

    SciTech Connect

    Jackson, Ayanna U.; Talaty, Nari; Cooks, R G; Van Berkel, Gary J

    2007-01-01

    Suppression of ion intensity in the presence of high salt matrices is common in most mass spectrometry ionization techniques. Desorption electrospray ionization (DESI) is an ionization method that exhibits salt tolerance, and this is investigated. DESI analysis was performed on three different drug mixtures in the presence of 0, 0.2, 2, 5, 10, and 20% NaCl:KCl weight by volume from seven different surfaces. At physiological concentrations individual drugs in each mixture were observed with each surface. Collision-induced dissociation (CID) was used to provide additional confirmation for select compounds. Multiple stage experiments, to MS5, were performed for select compounds. Even in the absence of added salt, the benzodiazepine containing mixture yielded sodium and potassium adducts of carbamazepine which masked the ions of interest. These adducts were eliminated by adding 0.1% 7M ammonium acetate to the standard methanol:water (1:1) spray solvent. Comparison of the salt tolerance of DESI with that of electrospray ionization (ESI) demonstrated much better signal/noise characteristics for DESI in this study. The salt tolerance of DESI was also studied by performing limit of detection and dynamic range experiments. Even at a salt concentration significantly above physiological concentrations, select surfaces were effective in providing spectra that allowed the ready identification of the compounds of interest. The already high salt tolerance of DESI can be optimized further by appropriate choices of surface and spray solution.

  6. Salt Tolerant and Sensitive Rice Varieties Display Differential Methylome Flexibility under Salt Stress

    PubMed Central

    Ferreira, Liliana J.; Azevedo, Vanessa; Maroco, João; Oliveira, M. Margarida; Santos, Ana Paula

    2015-01-01

    DNA methylation has been referred as an important player in plant genomic responses to environmental stresses but correlations between the methylome plasticity and specific traits of interest are still far from being understood. In this study, we inspected global DNA methylation levels in salt tolerant and sensitive rice varieties upon salt stress imposition. Global DNA methylation was quantified using the 5-methylcytosine (5mC) antibody and an ELISA-based technique, which is an affordable and quite pioneer assay in plants, and in situ imaging of methylation sites in interphase nuclei of tissue sections. Variations of global DNA methylation levels in response to salt stress were tissue- and genotype-dependent. We show a connection between a higher ability of DNA methylation adjustment levels and salt stress tolerance. The salt-tolerant rice variety Pokkali was remarkable in its ability to quickly relax DNA methylation in response to salt stress. In spite of the same tendency for reduction of global methylation under salinity, in the salt-sensitive rice variety IR29 such reduction was not statistically supported. In ‘Pokkali’, the salt stress-induced demethylation may be linked to active demethylation due to increased expression of DNA demethylases under salt stress. In ‘IR29’, the induction of both DNA demethylases and methyltransferases may explain the lower plasticity of DNA methylation. We further show that mutations for epigenetic regulators affected specific phenotypic parameters related to salinity tolerance, such as the root length and biomass. This work emphasizes the role of differential methylome flexibility between salt tolerant and salt sensitive rice varieties as an important player in salt stress tolerance, reinforcing the need to better understand the connection between epigenetic networks and plant responses to environmental stresses. PMID:25932633

  7. Engineering salt-tolerant Brassica plants: Characterization of yield and seed oil quality in transgenic plants with increased vacuolar sodium accumulation

    PubMed Central

    Zhang, Hong-Xia; Hodson, Joanna N.; Williams, John P.; Blumwald, Eduardo

    2001-01-01

    Transgenic Brassica napus plants overexpressing AtNHX1, a vacuolar Na+/H+ antiport from Arabidopsis thaliana, were able to grow, flower, and produce seeds in the presence of 200 mM sodium chloride. Although the transgenic plants grown in high salinity accumulated sodium up to 6% of their dry weight, growth of the these plants was only marginally affected by the high salt concentration. Moreover, seed yields and the seed oil quality were not affected by the high salinity of the soil. Our results demonstrate the potential use of these transgenic plants for agricultural use in saline soils. Our findings, showing that the modification of a single trait significantly improved the salinity tolerance of this crop plant, suggest that with a combination of breeding and transgenic plants it could be possible to produce salt-tolerant crops with far fewer target traits than had been anticipated. PMID:11606781

  8. Salt tolerant chromatography provides salt tolerance and a better selectivity for protein monomer separations.

    PubMed

    Yoshimoto, Noriko; Itoh, Daisuke; Isakari, Yu; Podgornik, Ales; Yamamoto, Shuichi

    2015-12-01

    Salt tolerant chromatography (STC) is an attractive method as buffer exchange during protein purification processes can be skipped; however, the retention and separation mechanism of such STC are still not fully understood. We carried out linear gradient elution (LGE) experiments of bovine serum albumin (BSA) including its dimer form by using poly-amine ligand STC. The peak salt concentration IR was measured as a function of normalized gradient slope GH, and the number of binding sites B was determined. The separation performance of monomer and dimer was much higher for STC. The IR values of BSA monomer and dimer for STC were much higher (IR > 0.5M) than those for conventional IEC. The IR values of arginine-Cl gradient decreased markedly compared to those of NaCl gradient whereas they did not change for conventional IEC. This might be due to combined effects of electrostatic and hydrophobic interaction to the retention of proteins in STC. Adding polyethylene glycol (PEG) into the mobile phase of IEC also increased the retention (salt tolerance) and the resolution of BSA monomer and dimer. Higher viscosity and low solubility of proteins due to PEG were disadvantages of this method. STC with poly-amine ligand might be also suited for the continuous flow-through separation of monomer. PMID:26472648

  9. Analysis of salt-tolerance genes in Zygosaccharomyces rouxii.

    PubMed

    Hou, Lihua; Wang, Meng; Wang, Cong; Wang, Chunling; Wang, Haiyong

    2013-07-01

    Zygosaccharomyces rouxii was mostly used in high-salt liquid fermentation of soy sauce. To better understand the osmo-adaption mechanism, two key salt-tolerance genes GPD1 coding for glycerol-3-phosphate dehydrogenase and FPS1 coding for a putative glycerol transporter were evaluated in the wild-type Z. rouxii (S) and a higher salt-tolerant mutant strain Z. rouxii 3-2 (S3-2) previously constructed. It was found that several mutations occurred in ZrGPD1 and ZrFPS1 in S3-2 compared with the control strain S. The mutation of ZrGPD1 in S3-2 resulted in the increase of transcription level of ZrGPD1 compared with the control. At the same time, the mutation of ZrFPS1 resulted in the decrease of transcription level of ZrFPS1. In addition, overexpression of S3-2GPD1 and S3-2FPS1 in Saccharomyces cerevisiae could cause the stronger salt tolerance compared to SGPD1 and SFPS1, respectively. The results suggested the improvement of salt tolerance in S3-2 was due to the increase of glycerol contents, which was resulted from the increase of transcription level of ZrGPD1 and the decrease of transcription level of ZrFPS1. PMID:23673487

  10. Isolation and molecular characterization of GmERF7, a soybean ethylene-response factor that increases salt stress tolerance in tobacco.

    PubMed

    Zhai, Ying; Wang, Ying; Li, Yanjie; Lei, Tingting; Yan, Fan; Su, Liantai; Li, Xiaowei; Zhao, Yan; Sun, Xin; Li, Jingwen; Wang, Qingyu

    2013-01-15

    Ethylene-response factors (ERFs) play an important role in regulating gene expression in plant responses to biotic and abiotic stresses. In this study, a new ERF transcription factor, GmERF7, was isolated from soybean. Sequence analysis showed that GmERF7 contained an AP2/ERF domain with 58 amino acids, two putative nuclear localization signal (NLS) domains, an acidic amino acid-rich transcriptional activation domain and a conserved N-terminal motif [MCGGAI(I/L)]. The expression of GmERF7 was induced by drought, salt, methyl jasmonate (MeJA), ethylene (ETH) and abscisic acid (ABA) treatments. However, the expression of GmERF7 decreased under cold treatment. GmERF7 localized to the nucleus when transiently expressed in onion epidermal cells. Furthermore, GmERF7 protein bound to the GCC-box element in vitro and activated the expression of the β-glucuronidase (GUS) reporter gene in tobacco leaves. Activities of GmERF7 promoter (GmERF7P) upregulated in tobacco leaves with 10h drought, salt and ETH treatments. However, activities of GmERF7P decreased with 10h cold and ABA treatments. Overexpression of GmERF7 in tobacco plants led to higher levels of chlorophyll and soluble carbohydrates and a lower level of malondialdehyde compared with wild-type tobacco plants under salt stress conditions, which indicated that GmERF7 enhanced salt tolerance in transgenic plants. PMID:23111158

  11. Comparing salt tolerance of beet cultivars and their halophytic ancestor: consequences of domestication and breeding programmes

    PubMed Central

    Rozema, Jelte; Cornelisse, Danny; Zhang, Yuancheng; Li, Hongxiu; Bruning, Bas; Katschnig, Diana; Broekman, Rob; Ji, Bin; van Bodegom, Peter

    2015-01-01

    Salt tolerance of higher plants is determined by a complex set of traits, the timing and rate of evolution of which are largely unknown. We compared the salt tolerance of cultivars of sugar beet and their ancestor, sea beet, in hydroponic studies and evaluated whether traditional domestication and more recent breeding have changed salt tolerance of the cultivars relative to their ancestor. Our comparison of salt tolerance of crop cultivars is based on values of the relative growth rate (RGR) of the entire plant at various salinity levels. We found considerable salt tolerance of the sea beet and slightly, but significantly, reduced salt tolerance of the sugar beet cultivars. This indicates that traditional domestication by selection for morphological traits such as leaf size, beet shape and size, enhanced productivity, sugar content and palatability slightly affected salt tolerance of sugar beet cultivars. Salt tolerance among four sugar beet cultivars, three of which have been claimed to be salt tolerant, did not differ. We analysed the components of RGR to understand the mechanism of salt tolerance at the whole-plant level. The growth rate reduction at higher salinity was linked with reduced leaf area at the whole-plant level (leaf area ratio) and at the individual leaf level (specific leaf area). The leaf weight fraction was not affected by increased salinity. On the other hand, succulence and leaf thickness and the net assimilation per unit of leaf area (unit leaf rate) increased in response to salt treatment, thus partially counteracting reduced capture of light by lower leaf area. This compensatory mechanism may form part of the salt tolerance mechanism of sea beet and the four studied sugar beet cultivars. Together, our results indicate that domestication of the halophytic ancestor sea beet slightly reduced salt tolerance and that breeding for improved salt tolerance of sugar beet cultivars has not been effective. PMID:25492122

  12. Overexpression of the Jatropha curcas JcERF1 gene coding an AP2/ERF-type transcription factor increases tolerance to salt in transgenic tobacco.

    PubMed

    Yang, Hua; Yu, Chuan; Yan, Jun; Wang, Xuehua; Chen, Fang; Zhao, Yun; Wei, Wei

    2014-11-01

    The JcERF1 gene, which is related to the ERF family (ethylene responsive factor coding genes), was isolated and characterized from the oil tree Jatropha curcas. The JcERF1 protein contains conserved an AP2/EREBP DNA-binding domain of 58 amino acid residues. The JcERF1 gene could be induced by abscisic acid, high salinity, hormones, and osmotic stress, suggesting that JcERF1 is regulated by certain components of the stress-signaling pathway. The full-length and C-terminus of JcERF1 driven by the GAL4 promoter functioned effectively as a transactivator in yeast, while its N-terminus was completely inactive. Transient expression analysis using a JcERF1-mGFP fusion gene in onion epidermal cells revealed that the JcERF1 protein is targeted to the nucleus. Transgenic tobacco plants carrying CaMV35S::JcERF1 fragments were shown to be much more salt tolerant compared to wild-type plants. Our results indicate that JcERF1 is a new member of the ERF transcription factors family that may play an important role in tolerance to environmental stress. PMID:25540008

  13. Bioenergetics of salt tolerance. Final report

    SciTech Connect

    Packer, L.

    1986-10-28

    Major findings are presented on how Synechococcus responds to a transition from low salt (12mM NaCl) to high salt (0.5 M NaCl) medium; we have studied immediate and long-term osmotic responses, identified deleterious effects of NaCl on cellular processes, and analyzed adaptations of the bioenergetic systems that permit the organism to tolerate a high salt environment. We have also developed new electron spin resonance methods for measuring intracellular O/sub 2/ concentrations and intracellular pH. In addition studies on the physiology and molecular mechanism of light-driven chloride transport by halorhodopsin in the halobacteria are reported. The ion-transport ATPase of halobacteria and the respiration-linked sodium transport system of the halotolerant bacterium, Bal were studied with respect to the role and functioning of ionic pumps. Chloride transport was shown to be an integral componet of the overall ion circulation in halobacterial cells, one which maintains internal salt concentration and therefore cellular volume. How halorhodopsin functions, its photointermediates, the nature of chloride-binding sites, the role of the deprotonation of the retinal Schiff-base, and how removal of most of the arginine residues, does not affect chloride-binding are reported. Methods were developed for the study of membrane-bound halobacterial ATPase, its solubilization and partial purification. 43 refs., 1 fig.

  14. Divergences in morphological changes and antioxidant responses in salt-tolerant and salt-sensitive rice seedlings after salt stress.

    PubMed

    Lee, Min Hee; Cho, Eun Ju; Wi, Seung Gon; Bae, Hyoungwoo; Kim, Ji Eun; Cho, Jae-Young; Lee, Sungbeom; Kim, Jin-Hong; Chung, Byung Yeoup

    2013-09-01

    Salinization plays a primary role in soil degradation and reduced agricultural productivity. We observed that salt stress reversed photosynthesis and reactive oxygen scavenging responses in leaves or roots of two rice cultivars, a salt-tolerant cultivar Pokkali and a salt-sensitive cultivar IR-29. Salt treatment (100 mM NaCl) on IR-29 decreased the maximum photochemical efficiency (Fv/Fm) and the photochemical quenching coefficient (qP), thereby inhibiting photosynthetic activity. By contrast, the salt treatment on Pokkali had the converse effect on Fv/Fm and qP, while increasing the nonphotochemical quenching coefficient (NPQ), thereby favoring photosynthetic activity. Notably, chloroplast or root cells in Pokkali maintained their ultrastructures largely intact under the salt stress, but, IR-29 showed severe disintegration of existing grana stacks, increase of plastoglobuli, and swelling of thylakoidal membranes in addition to collapsed vascular region in adventitious roots. Pokkali is known to have higher hydrogen peroxide (H2O2)-scavenging enzyme activities in non-treated seedlings, including ascorbate peroxidase, catalase, and peroxidase activities. However, these enzymatic activities were induced to a greater extent in IR-29 by the salt stress. While the level of endogenous H2O2 was lower in Pokkali than in IR-29, it was reversed upon the salt treatment. Nevertheless, the decreased amount of H2O2 in IR-29 upon the salt stress didn't result in a high scavenging activity of total cell extracts for H2O2, as well as O2(·-) and (·)OH species. The present study suggests that the tolerance to the moderate salinity in Pokkali derives largely from the constitutively maintained antioxidant enzymatic activities as well as the induced antioxidant enzyme system. PMID:23811121

  15. Salt Tolerance and Polyphyly in the Cyanobacterium Chroococcidiopsis (Pleurocapsales)1

    NASA Technical Reports Server (NTRS)

    Cumbers, John Robert; Rothschild, Lynn J.

    2014-01-01

    Chroococcidiopsis Geitler (Geitler 1933) is a genus of cyanobacteria containing desiccation and radiation resistant species. Members of the genus live in habitats ranging from hot and cold deserts to fresh and saltwater environments. Morphology and cell division pattern have historically been used to define the genus. To better understand the genetic and phenotypic diversity of the genus, 15 species were selected that had been previously isolated from different locations, including salt and freshwater environments. Four markers were sequenced from these 15 species, the 16S rRNA, rbcL, desC1 and gltX genes. Phylogenetic trees were generated which identified two distinct clades, a salt-tolerant clade and a freshwater clade. This study demonstrates that the genus is polyphyletic based on saltwater and freshwater phenotypes. To understand the resistance to salt in more details, species were grown on a range of sea salt concentrations which demonstrated that the freshwater species were salt-intolerant whilst the saltwater species required salt for growth. This study shows an increased resolution of the phylogeny of Chroococcidiopsis and provides further evidence that the genus is polyphyletic and should be reclassified to improve clarity in the literature.

  16. The Reaumuria trigyna leucoanthocyanidin dioxygenase (RtLDOX) gene complements anthocyanidin synthesis and increases the salt tolerance potential of a transgenic Arabidopsis LDOX mutant.

    PubMed

    Zhang, Huirong; Du, Chao; Wang, Yan; Wang, Jia; Zheng, Linlin; Wang, Yingchun

    2016-09-01

    Reaumuria trigyna is a typical, native desert halophyte that grows under extreme conditions in Inner Mongolia. In a previous transcriptomic profiling analysis, flavonoid pathway-related genes in R. trigyna showed significant differences in transcript abundance under salt stress. Leucoanthocyanidin dioxygenase (LDOX, EC 1.14.11.19) is one of three dioxygenases in the flavonoid pathway that catalyzes the formation of anthocyanidins from leucoanthocyanidins. In this study, we cloned the full-length cDNA of R. trigyna LDOX (RtLDOX), and found RtLDOX recombinant protein was able to replace flavanone-3-hydroxylase (F3H, EC 1.14.11.9), another dioxygenase in the flavonoid pathway, to convert naringenin to dihydrokaempferol in vitro. R. trigyna LDOX can complement the Arabidopsis LDOX mutant transparent testa11 (tt11-11), which has reduced proanthocyanin (PA) and anthocyanin levels in seeds, to accumulate these two compounds. Thus, RtLDOX acts as a multifunctional dioxygenase to effect the synthesis of PA and anthocyanins and can perform F3H dioxygenase activities in the flavonoid biosynthesis pathway. The RtLDOX promoter harbored many cis-acting elements that might be recognized and bound by transcription factors related to stress response. RtLDOX expression was strongly increased under salt stress, and RtLDOX transgenic Arabidopsis mutant under NaCl stress accumulated the content of flavonoids leading to an increased antioxidant activities and plant biomass. These results suggest that RtLDOX as a multifunctional dioxygenase in flavonoid biosynthesis involves in enhancing plant response to NaCl stress. PMID:27219053

  17. Co-existence of salt and drought tolerance in Triticeae.

    PubMed

    Farooq, S; Azam, F

    2001-01-01

    Cell membrane stability (CMS) technique was used to screen for drought tolerance, salt tolerant accessions of three Aegilops species, Ae. tauschii, Ae. cylindrica, Ae. geniculata and two hexaploid wheat (Tricitum aestivum L.) cultivars comprising salt tolerant LU-26 and drought tolerant Chakwal-86. The objectives were to see how valid it is for a salt tolerant plant to be drought tolerant as well and to identify the character(s) that may contribute to drought tolerance. Three moisture levels equal to 100, 50 and 25% saturation capacity of the soil were used for plant cultivation. Injury percentage (IP) based on in-vitro desiccation induced by polyethylene glycol (PEG) in leaf tissue was measured through the conductivity of the electrolyte leakage. Injury percentage decreased in all the test material with decrease in soil moisture contents. Ae. cylindrica exhibited minimum injury at 100% soil moisture level followed by Ae. tauschii and Ae. geniculata while drought tolerant wheat cultivars exhibited the maximum. The wheat cultivar Chakwal-86 has been developed for dry areas, with low soil moisture levels, and high water potential enhances the injury percentage. Aegilops cylindrica is a salt tolerant species and can thus tolerate water deficit conditions created due to low osmotic potential. Potassium appeared to play an important role in drought tolerance which was evident from high K+ contents and low K+ leakage from Aegilops cylindrica and drought tolerant wheat cultivar Chakwal-86. It was inferred from the study that salt tolerant species might prove drought tolerant in the areas where water deficit prevails due to the ability to create low intracellular osmotic potentials. PMID:12152336

  18. Lipid composition of mangrove and its relevance to salt tolerance.

    PubMed

    Oku, Hirosuke; Baba, Shigeyuki; Koga, Hiroya; Takara, Kensaku; Iwasaki, Hironori

    2003-02-01

    Lipid compositions of mangrove trees were studied in relation to the salt-tolerance mechanism. Leaves and roots were obtained from seven mature mangrove trees on Iriomote Island, Okinawa: Bruguiera gymnorrhiza, Rhizophora stylosa, Kandelia candel, Lumnitzera racemosa, Avicennia marina, Pemphis acidula and Sonneratia alba. Lipids of mangrove leaves mainly consisted of 11 lipid classes: polar lipids, unknown (UK) 1-6, sterols, triacyl glycerols, wax ester and sterol ester (UK 3 and 4 were found to be tri-terpenoid alcohol in this study). Of these lipid classes, sterol ester was the main lipid in all species comprising 17.6-33.7% of total lipids. Analysis of the chemical structure found that the sterol esters mainly consisted of fatty acid esters of tri-terpenoid alcohols. One major tri-terpenoid alcohol was identified to be lupeol by interpretation of infrared resonance, nuclear magnetic resonance and mass spectrometry. Because of the unique anatomy of the mangrove root, lipid analyses were made separately for epidermis, cortex and innermost stele, respectively. The concentration of free tri-terpenoid alcohols showed a higher tendency in the outside part than in the inside portion of the roots, suggesting their protective roles. Relevance of lipid composition to salt tolerance was studied with propagules of K. candel and B. gymnorrhiza planted with varied salt concentrations. The proportions of free tri-terpenoids increased with salinity in both leaves and roots of K. candel, and only in roots of B. gymnorrhiza. No salt-dependent changes were noted in the phospholipid and fatty acid compositions in both species. These findings suggested that salt stress specifically modulated the terpenoid concentrations in mangroves. PMID:12605298

  19. ARS-NLT-SALT AND ARS-NLT-SALT/B SALINE TOLERANT NARROW LEAF TREFOIL GERMPLASM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ARS-NLT-SALT and ARS-NLT-SALT/B are narrow leaf trefoil germplasm that are tolerant of saline germination conditions that were developed from the broad based narrow leaf trefoil germplasm ARS-1207 using two cycles of saline condition selection during seed germination. ARS-NLT-SALT was developed usin...

  20. Increasing ideological tolerance in social psychology.

    PubMed

    Inbar, Yoel; Lammers, Joris

    2015-01-01

    We argue that recognizing current ideological diversity in social psychology and promoting tolerance of minority views is just as important as increasing the number of non-liberal researchers. Increasing tolerance will allow individuals in the minority to express dissenting views, which will improve psychological science by reducing bias. We present four recommendations for increasing tolerance. PMID:26786671

  1. Expression of an Arabidopsis Vacuolar H+-pyrophosphatase Gene (AVP1) in Cotton Improves Drought- and Salt Tolerance and Increases Fibre Yield in the Field Conditions.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Arabidopsis gene AVP1 encodes a vacuolar pyrophosphatase that functions as a proton pump on the vacuolar membrane. Overexpression of AVP1 in Arabidopsis, tomato and rice enhances plant performance under salt and drought stress conditions, because up-regulation of the type I H+PPase from Arabido...

  2. Expression of an arabidopsis vacuolar H+-pyrophosphatase gene (AVP1) in cotton improves drought- and salt tolerance and increases fibre yield in the field conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Arabidopsis gene AVP1 encodes a vacuolar pyrophosphatase that functions as a proton pump on the vacuolar membrane. Overexpression of AVP1 in Arabidopsis, tomato and rice enhances plant performance under salt and drought stress conditions, because up-regulation of the type I H+-PPase from Arabid...

  3. Salt tolerance at single cell level in giant-celled Characeae

    PubMed Central

    Beilby, Mary J.

    2015-01-01

    Characean plants provide an excellent experimental system for electrophysiology and physiology due to: (i) very large cell size, (ii) position on phylogenetic tree near the origin of land plants and (iii) continuous spectrum from very salt sensitive to very salt tolerant species. A range of experimental techniques is described, some unique to characean plants. Application of these methods provided electrical characteristics of membrane transporters, which dominate the membrane conductance under different outside conditions. With this considerable background knowledge the electrophysiology of salt sensitive and salt tolerant genera can be compared under salt and/or osmotic stress. Both salt tolerant and salt sensitive Characeae show a rise in membrane conductance and simultaneous increase in Na+ influx upon exposure to saline medium. Salt tolerant Chara longifolia and Lamprothamnium sp. exhibit proton pump stimulation upon both turgor decrease and salinity increase, allowing the membrane PD to remain negative. The turgor is regulated through the inward K+ rectifier and 2H+/Cl- symporter. Lamprothamnium plants can survive in hypersaline media up to twice seawater strength and withstand large sudden changes in salinity. Salt sensitive C. australis succumbs to 50–100 mM NaCl in few days. Cells exhibit no pump stimulation upon turgor decrease and at best transient pump stimulation upon salinity increase. Turgor is not regulated. The membrane PD exhibits characteristic noise upon exposure to salinity. Depolarization of membrane PD to excitation threshold sets off trains of action potentials, leading to further loses of K+ and Cl-. In final stages of salt damage the H+/OH- channels are thought to become the dominant transporter, dissipating the proton gradient and bringing the cell PD close to 0. The differences in transporter electrophysiology and their synergy under osmotic and/or saline stress in salt sensitive and salt tolerant characean cells are discussed in

  4. Evaluation of cotton germplasm and breeding populations for salt tolerance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three experiments were conducted in 2005 and 2007 to evaluate a total of 211 cotton germplasm and breeding lines for salt tolerance in the greenhouses. The randomized complete block designs with two or three replications were employed for those experiments. 200 mM salt solutions or tap water were ap...

  5. Assessment of salt tolerant plants to remediate saline soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil salinity has intensified in the James River valley in east central South Dakota in the past 20 years. Surface evaporation on poorly drained and subirrigated soils leaves salts on the soil surface. Replacing evaporation from the soil surface with transpiration through deep-rooted salt-tolerant...

  6. (Bioenergetics of salt tolerance): Progress report, 1980-1983

    SciTech Connect

    Not Available

    1983-01-01

    We have developed novel and useful techniques based on ESR probes for measuring intracellular volumes and membrane permeability, as well as adapted more commonly used ones for various measurements in work on salt tolerance. Biological membrane systems, ranging from simpler (halobacteria and cyanobacteria) to more complex (sugar beet leaf segments) have been studied where specific problems related to salt tolerance and ionic transport were identified. The role of sodium and chloride transport in maintaining cellular volumes were studied with respect to the events which take place during adaptation to salt and their relationship to nitrate assimilation. 14 refs.

  7. Four pathogenic Candida species differ in salt tolerance.

    PubMed

    Krauke, Yannick; Sychrova, Hana

    2010-10-01

    The virulence of Candida species depends on many environmental conditions, including extracellular pH and concentration of alkali metal cations. Tests of the tolerance/sensitivity of four pathogenic Candida species (C. albicans, C. dubliniensis, C. glabrata, and C. parapsilosis) to alkali metal cations under various growth conditions revealed significant differences among these species. Though all of them can be classified as rather osmotolerant yeast species, they exhibit different levels of tolerance to different salts. C. parapsilosis and C. albicans are the most salt-tolerant in general; C. dubliniensis is the least tolerant on rich YPD media and C. glabrata on acidic (pH 3.5) minimal YNB medium. C. dubliniensis is relatively salt-sensitive in spite of its ability to maintain as high intracellular K(+)/Na(+) ratio as its highly salt-tolerant relative C. albicans. On the other hand, C. parapsilosis can grow in the presence of very high external NaCl concentrations in spite of its high intracellular Na(+) concentrations (and thus lower K(+)/Na(+) ratio) and thus resembles salt-tolerant (halophilic) Debaryomyces hansenii. PMID:20300937

  8. Physical Chemistry and Evolution of Salt Tolerance in Halobacteria

    NASA Astrophysics Data System (ADS)

    Lanyi, Janos K.

    1980-06-01

    The cellular constituents of extremely halophilic bacteria not only tolerate high salt concentration, but in many cases require it for optical functioning. The characteristics affected by salt include enzyme activity, stability, allosteric regulation, conformation and subunit association. The salt effects are of two major kinds: electrostatic shielding of negative charges by cations at low salt concentration, and hydrophobic stabilization by salting-out type salts at high salt concentration. The composition of halobacterial proteins shows an excess of acidic amino acids and a deficiency of nonpolar amino acids, which accounts for these effects. Since the cohesive forces are weaker and the repulsing forces are stronger in these proteins, preventing aggregation in salt, these structures are no longer suited for functioning in the absence of high salt concentrations. Unlike these nonspecific effects, ribosomes in halobacteria show marked preference for potassium over sodium ions. To ensure the proper intracellular ionic composition, powerful ion transport systems have evolved in the halobacteria, resulting in the extrusion of sodium ions and their replacement by potassium. It is likely that such membrane transport system for ionic movements is a necessary requisite for salt tolerance.

  9. Physical chemistry and evolution of salt tolerance in halobacteria

    NASA Technical Reports Server (NTRS)

    Lanyi, J. K.

    1980-01-01

    The cellular constituents of extremely halophilic bacteria not only tolerate high salt concentration, but in many cases require it for optical functioning. The characteristics affected by salt include enzyme activity, stability, allosteric regulation, conformation and subunit association. The salt effects are of two major kinds: electrostatic shielding of negative charges by cations at low salt concentration, and hydrophobic stabilization by salting-out type salts at high salt concentration. The composition of halobacterial proteins shows an excess of acidic amino acids and a deficiency of nonpolar amino acids, which accounts for these effects. Since the cohesive forces are weaker and the repulsing forces are stronger in these proteins, preventing aggregation in salt, these structures are no longer suited for functioning in the absence of high salt concentrations. Unlike these nonspecific effects, ribosomes in halobacteria show marked preference for potassium over sodium ions. To ensure the proper intracellular ionic composition, powerful ion transport systems have evolved in the halobacteria, resulting in the extrusion of sodium ions and their replacement by potassium. It is likely that such membrane transport system for ionic movements is a necessary requisite for salt tolerance.

  10. A Novel α/β-Hydrolase Gene IbMas Enhances Salt Tolerance in Transgenic Sweetpotato

    PubMed Central

    Song, Xuejin; He, Shaozhen; Liu, Qingchang

    2014-01-01

    Salt stress is one of the major environmental stresses in agriculture worldwide and affects crop productivity and quality. The development of crops with elevated levels of salt tolerance is therefore highly desirable. In the present study, a novel maspardin gene, named IbMas, was isolated from salt-tolerant sweetpotato (Ipomoea batatas (L.) Lam.) line ND98. IbMas contains maspardin domain and belongs to α/β-hydrolase superfamily. Expression of IbMas was up-regulated in sweetpotato under salt stress and ABA treatment. The IbMas-overexpressing sweetpotato (cv. Shangshu 19) plants exhibited significantly higher salt tolerance compared with the wild-type. Proline content was significantly increased, whereas malonaldehyde content was significantly decreased in the transgenic plants. The activities of superoxide dismutase (SOD) and photosynthesis were significantly enhanced in the transgenic plants. H2O2 was also found to be significantly less accumulated in the transgenic plants than in the wild-type. Overexpression of IbMas up-regulated the salt stress responsive genes, including pyrroline-5-carboxylate synthase, pyrroline-5-carboxylate reductase, SOD, psbA and phosphoribulokinase genes, under salt stress. These findings suggest that overexpression of IbMas enhances salt tolerance of the transgenic sweetpotato plants by regulating osmotic balance, protecting membrane integrity and photosynthesis and increasing reactive oxygen species scavenging capacity. PMID:25501819

  11. Increased tolerance to humans among disturbed wildlife

    PubMed Central

    Samia, Diogo S. M.; Nakagawa, Shinichi; Nomura, Fausto; Rangel, Thiago F.; Blumstein, Daniel T.

    2015-01-01

    Human disturbance drives the decline of many species, both directly and indirectly. Nonetheless, some species do particularly well around humans. One mechanism that may explain coexistence is the degree to which a species tolerates human disturbance. Here we provide a comprehensive meta-analysis of birds, mammals and lizards to investigate species tolerance of human disturbance and explore the drivers of this tolerance in birds. We find that, overall, disturbed populations of the three major taxa are more tolerant of human disturbance than less disturbed populations. The best predictors of the direction and magnitude of bird tolerance of human disturbance are the type of disturbed area (urbanized birds are more tolerant than rural or suburban populations) and body mass (large birds are more tolerant than small birds). By identifying specific features associated with tolerance, these results guide evidence-based conservation strategies to predict and manage the impacts of increasing human disturbance on birds. PMID:26568451

  12. Increased tolerance to humans among disturbed wildlife.

    PubMed

    Samia, Diogo S M; Nakagawa, Shinichi; Nomura, Fausto; Rangel, Thiago F; Blumstein, Daniel T

    2015-01-01

    Human disturbance drives the decline of many species, both directly and indirectly. Nonetheless, some species do particularly well around humans. One mechanism that may explain coexistence is the degree to which a species tolerates human disturbance. Here we provide a comprehensive meta-analysis of birds, mammals and lizards to investigate species tolerance of human disturbance and explore the drivers of this tolerance in birds. We find that, overall, disturbed populations of the three major taxa are more tolerant of human disturbance than less disturbed populations. The best predictors of the direction and magnitude of bird tolerance of human disturbance are the type of disturbed area (urbanized birds are more tolerant than rural or suburban populations) and body mass (large birds are more tolerant than small birds). By identifying specific features associated with tolerance, these results guide evidence-based conservation strategies to predict and manage the impacts of increasing human disturbance on birds. PMID:26568451

  13. Reduction of perchlorate and nitrate by salt tolerant bacteria.

    PubMed

    Okeke, Benedict C; Giblin, Tara; Frankenberger, William T

    2002-01-01

    Spent regenerant brine from ion-exchange technology for the removal of perchlorate and nitrate produces a high salt waste stream, which requires remediation before disposal. Bioremediation is an attractive treatment option. In this study, we enriched for salt tolerant bacteria from sediments from Cargill salt evaporation facility (California, USA), the Salton Sea (California, USA), and a high density hydrocarbon oxidizing bacterial cocktail. The bacterial cocktail enrichment culture reduced ClO4- from 500 to 260 mg 1 in 4 weeks. Salt tolerant bacterial isolates from the enrichment cultures and two denitrifying salt tolerant bacteria, Haloferax denitrificans and Parococcus halodenitricans, substantially reduced perchlorate. The highest rate of perchlorate removal was recorded with the isolate, Citrobacter sp.: 32% reduction in 1 week. This bacterium substantially reduced perchlorate in 0-5% NaCl solutions and maximally at 30 degrees C and at an initial pH 7.5. In simulated brines containing 7.5% total solids, the Citrobacter sp. significantly reduced both perchlorate and nitrate with 34.9 and 15.6% reduction, respectively, in 1 week. Coculture of a potent perchlorate reducing, non-salt tolerant (non-saline) bacterium, perclace and the Citrobacter sp. proved most effective for perchlorate removal in the brine (46.4% in 1 week). This study demonstrates that both anions can be reduced in treatment of brines from ion exchange systems. PMID:12009133

  14. Overexpression of the soybean GmERF3 gene, an AP2/ERF type transcription factor for increased tolerances to salt, drought, and diseases in transgenic tobacco.

    PubMed

    Zhang, Gaiyun; Chen, Ming; Li, Liancheng; Xu, Zhaoshi; Chen, Xueping; Guo, Jiaming; Ma, Youzhi

    2009-01-01

    A new member of the AP2/ERF transcription factor family, GmERF3, was isolated from soybean. Sequence analysis showed that GmERF3 contained an AP2/ERF domain of 58 amino acids and two putative nuclear localization signal (NLS) domains. It belonged to a group IV protein in the ERF (ethylene response factor) subfamily as typified by a conserved N-terminal motif [MCGGAI(I/L)]. Expression of GmERF3 was induced by treatments with high salinity, drought, abscisic acid (ABA), salicylic acid (SA), jasmonic acid (JA), ethylene (ET), and soybean mosaic virus (SMV), whereas there was no significant GmERF3 mRNA accumulation under cold stress treatment. GmERF3 could bind to the GCC box and DRE/CRT element, and was targeted to the nucleus when transiently expressed in onion epidermal cells. The GmERF3 protein fused to the GAL4 DNA-binding domain to activate transcription of reporter genes in yeast. Ectopic expression of the GmERF3 gene in transgenic tobacco plants induced the expression of some PR genes and enhanced resistance against infection by Ralstonia solanacearum, Alternaria alternata, and tobacco mosaic virus (TMV), and gave tolerance to high salinity and dehydration stresses. Furthermore, overexpression of GmERF3 in transgenic tobacco led to higher levels of free proline and soluble carbohydrates compared to wild-type plants under drought conditions. The overall results suggested that GmERF3 as an AP2/ERF transcription factor may play dual roles in response to biotic and abiotic stresses in plants. PMID:19602544

  15. SALT TOLERANCE ASSESSMENT OF KENTUCKY BLUEGRASS CULTIVARS SELECTED FOR DROUGHT TOLERANCE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Six selections of Kentucky bluegrass (Poa pratensis L.) cultivars, selected based on their drought tolerance under field and growth chamber conditions in New Brunswick, NJ., were evaluated for salt tolerance based on yield and growth rates at eight soil water salinities [2 (control), 6,8,10,12,14,18...

  16. Creating Drought- and Salt-Tolerant Crops by Overexpressing a Vacuolar Pyrophosphatase Gene

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increased expression of an Arabidopsis vacuolar pyrophosphatase gene, AVP1, leads to increased drought and salt tolerance in transgenic plants, which has been demonstrated in laboratory and field conditions. The molecular mechanism of AVP1-mediated drought resistance is likely due to increased proto...

  17. FTIR and EDXRF investigations of salt tolerant soybean mutants

    NASA Astrophysics Data System (ADS)

    Akyuz, Sevim; Akyuz, Tanil; Celik, Ozge; Atak, Cimen

    2013-07-01

    Molecular structure and elemental composition of soybean (Glycine max L. Merr.) seeds of S04-05 (Ustun-1) variety together with its salt tolerant mutants were investigated by Fourier transform infrared (FTIR) and energy dispersive X-ray fluorescence (EDXRF) spectrometry. Salt tolerant soybean mutants were in vivo and in vitro selected from the M2 generation of gamma irradiated S04-05 soybean variety. Examination of the secondary structure of proteins revealed the presence of some alterations in soybean mutants in comparison to those of the control groups. The difference IR spectra indicated that salt tolerant mutants (M2) have less protein but more lipid contents. Chemometric treatment of the FTIR data was performed and principle component analysis (PCA) revealed clear difference between control group of seeds and mutants. EDXRF analysis showed that salt tolerant mutants considerably contained more chlorine, copper and zinc elements when compared to the control group, although most of the trace elements concentrations were not significantly altered.

  18. 77 FR 21676 - Silicic Acid, Sodium Salt etc.; Tolerance Exemption

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-11

    ...This regulation establishes an exemption from the requirement of a tolerance for residues of Silicic acid, sodium salt, reaction products with chlorotrimethylsilane and iso-propyl alcohol, reaction with poly(oxypropylene)-poly(oxyethylene) glycol; when used as an inert ingredient in a pesticide chemical formulation. Dow Corning Corporation submitted a petition to EPA under the Federal Food,......

  19. Salt- and alkaline-tolerance are linked in Acacia.

    PubMed

    Bui, Elisabeth N; Thornhill, Andrew; Miller, Joseph T

    2014-07-01

    Saline or alkaline soils present a strong stress on plants that together may be even more deleterious than alone. Australia's soils are old and contain large, sometimes overlapping, areas of high salt and alkalinity. Acacia and other Australian plant lineages have evolved in this stressful soil environment and present an opportunity to understand the evolution of salt and alkalinity tolerance. We investigate this evolution by predicting the average soil salinity and pH for 503 Acacia species and mapping the response onto a maximum-likelihood phylogeny. We find that salinity and alkalinity tolerance have evolved repeatedly and often together over 25 Ma of the Acacia radiation in Australia. Geographically restricted species are often tolerant of extreme conditions. Distantly related species are sympatric in the most extreme soil environments, suggesting lack of niche saturation. There is strong evidence that many Acacia have distributions affected by salinity and alkalinity and that preference is lineage specific. PMID:25079493

  20. Dissipation of excess photosynthetic energy contributes to salinity tolerance: a comparative study of salt-tolerant Ricinus communis and salt-sensitive Jatropha curcas.

    PubMed

    Lima Neto, Milton C; Lobo, Ana K M; Martins, Marcio O; Fontenele, Adilton V; Silveira, Joaquim Albenisio G

    2014-01-01

    The relationships between salt tolerance and photosynthetic mechanisms of excess energy dissipation were assessed using two species that exhibit contrasting responses to salinity, Ricinus communis (tolerant) and Jatropha curcas (sensitive). The salt tolerance of R. communis was indicated by unchanged electrolyte leakage (cellular integrity) and dry weight in leaves, whereas these parameters were greatly affected in J. curcas. The leaf Na+ content was similar in both species. Photosynthesis was intensely decreased in both species, but the reduction was more pronounced in J. curcas. In this species biochemical limitations in photosynthesis were more prominent, as indicated by increased C(i) values and decreased Rubisco activity. Salinity decreased both the V(cmax) (in vivo Rubisco activity) and J(max) (maximum electron transport rate) more significantly in J. curcas. The higher tolerance in R. communis was positively associated with higher photorespiratory activity, nitrate assimilation and higher cyclic electron flow. The high activity of these alternative electron sinks in R. communis was closely associated with a more efficient photoprotection mechanism. In conclusion, salt tolerance in R. communis, compared with J. curcas, is related to higher electron partitioning from the photosynthetic electron transport chain to alternative sinks. PMID:24094996

  1. Thinopyrum ponticum chromatin-integrated wheat genome shows salt-tolerance at germination stage.

    PubMed

    Yuan, Wen-Ye; Tomita, Motonori

    2015-01-01

    A wild wheatgrass, Thinopyrum ponticum (2n = 10x = 70), which exhibits substantially higher levels of salt tolerance than cultivated wheat, was employed to transfer its salt tolerance to common wheat by means of wide hybridization. A highly salt-tolerant wheat line S148 (2n = 42) was obtained from the BC3F2 progenies between Triticum aestivum (2n = 42) and Th. ponticum. In the cross of S148 × salt-sensitive wheat variety Chinese Spring, the BC4F2 seeds at germination stage segregated into a ratio of 3 salt tolerant to 1 salt sensitive, indicating that the salt tolerance was conferred by a dominant gene block. Genomic in situ hybridization analysis revealed that S148 had a single pair of Th. ponticum-T. aestivum translocated chromosomes bearing the salt-tolerance. This is an initial step of molecular breeding for salt-tolerant wheat. PMID:25809604

  2. Molecular and physiological responses to abscisic acid and salts in roots of salt-sensitive and salt-tolerant Indica rice varieties.

    PubMed Central

    Moons, A; Bauw, G; Prinsen, E; Van Montagu, M; Van der Straeten, D

    1995-01-01

    The Indica rice (Oryza sativa L.) varieties Pokkali and Nona Bokra are well-known salt tolerance donors in classical breeding. In an attempt to understand the molecular basis of their tolerance, physiological and gene expression studies were initiated. The effect of abscisic acid (ABA) on total proteins in roots from 12-d-old seedlings of Pokkali, Nona Bokra, and the salt-sensitive cultivar Taichung N1 were analyzed on two-dimensional gels. The abundance of ABA-induced proteins was highest in the most tolerant variety, Pokkali. Three ABA-responsive proteins, present at different levels in roots from tolerant and sensitive varieties, were further characterized by partial amino acid analysis. A novel histidine-rich protein and two types of late embryogenesis abundant (LEA) proteins were identified. Protein immunoblotting revealed that the levels of dehydrins and group 3 LEA proteins were significantly higher in roots from tolerant compared with sensitive varieties. Endogenous ABA levels showed a transient increase in roots exposed to osmotic shock (150 mM NaCl). Peak ABA concentrations were 30-fold higher for Nona Bokra and 6-fold higher for Pokkali compared with Taichung N1. Both the salt-induced endogenous ABA levels and a greater molecular response of root tissue to ABA were associated with the varietal differences in tolerance. PMID:7870812

  3. Silicon-mediated changes in polyamines participate in silicon-induced salt tolerance in Sorghum bicolor L.

    PubMed

    Yin, Lina; Wang, Shiwen; Tanaka, Kiyoshi; Fujihara, Shinsuke; Itai, Akihiro; Den, Xiping; Zhang, Suiqi

    2016-02-01

    Silicon (Si) is generally considered a beneficial element for the growth of higher plants, especially under stress conditions, but the mechanisms remain unclear. Here, we tested the hypothesis that Si improves salt tolerance through mediating important metabolism processes rather than acting as a mere mechanical barrier. Seedlings of sorghum (Sorghum bicolor L.) growing in hydroponic culture were treated with NaCl (100 mm) combined with or without Si (0.83 mm). The result showed that supplemental Si enhanced sorghum salt tolerance by decreasing Na(+) accumulation. Simultaneously, polyamine (PA) levels were increased and ethylene precursor (1-aminocyclopropane-1-carboxylic acid: ACC) concentrations were decreased. Several key PA synthesis genes were up-regulated by Si under salt stress. To further confirm the role of PA in Si-mediated salt tolerance, seedlings were exposed to spermidine (Spd) or a PA synthesis inhibitor (dicyclohexylammonium sulphate, DCHA) combined with salt and Si. Exogenous Spd showed similar effects as Si under salt stress whereas exogenous DCHA eliminated Si-enhanced salt tolerance and the beneficial effect of Si in decreasing Na(+) accumulation. These results indicate that PAs and ACC are involved in Si-induced salt tolerance in sorghum and provide evidence that Si plays an active role in mediating salt tolerance. PMID:25753986

  4. [Physiological response and salt-tolerance of Gleditsia microphylla under NaCl stress].

    PubMed

    Lu, Bin; Hou, Yue-min; Li, Xin-yang; Chang, Yue-xia; Huang, Da-zhuang; Lu, Bing-she

    2015-11-01

    In order to exploit the salt-tolerance ability and mechanism of Gleditsia microphylla, the plant growth, cell membrane permeability, the activities of cell protective enzymes, and the distri- butions of Na+ and K+ in different tissues were investigated under various NaCl stress (0.053%, 0.15%, 0.3%, 0.45% and 0.6%) with potted two-year seedlings. The results were as follows: With the increase of NaCl concentration, the seedling growth decreased while the salt injured index in- creased, and the salt-tolerance thresholds of seedling was 0.42% NaCl. With the NaCl concentration increasing, the membrane permeability, superoxide anion radical generating rate and MDA content increased grandly, while the activities of SOD, POD and CAT demonstrated an increase-decrease curve which reached the peak at 0.3% or 0.45%. Under the high salt stress condition, the supero- xide anion could be consumed timely by increasing the activities of SOD, POD and CAT enzymes, which was useful to avoid cell injure. Under salt stress condition, the Na+ content in different tissues increased gradually, following the order of root > leaf > stem, and the K+ content and K+/Na+ in different tissues decreased, following the order of leaf > root > stem. The K+-Na+ selective transpor- tation coefficients (S(K+) · Na+) of stem and leaf tissues under the soil NaCl stress condition were both increased, following the order of leaf > stem. In conclusion, the findings suggested that the salt- adaptation mechanisms of G. microphylla were root salt-rejection by Na+ accumulation and restriction in root tissue and leaf salt-tolerance by a remarkably increased ability of K+ selective absorption and accumulation in leaf tissue. PMID:26915182

  5. Tetraploid citrus rootstocks are more tolerant to salt stress than diploid.

    PubMed

    Saleh, Basel; Allario, Thierry; Dambier, Dominique; Ollitrault, Patrick; Morillon, Raphaël

    2008-09-01

    Citrus trees are subject to several abiotic constraints such as salinity. Providing new rootstocks more tolerant is thus a requirement. In this article, we investigated salt stress tolerance of three tetraploid rootstock genotypes when compared to their respective diploid rootstocks (Poncirus trifoliata, Carrizo citrange, Cleopatra mandarin). Plant growth, leaf fall and ion contents were investigated. At the end of the experiment, leaf fall was observed only for diploid Poncirus trifoliata plants as well as chlorosis symptoms for Poncirus trifoliata and Carrizo citrange diploid plants. The diploid Cleopatra mandarin plants growth rate was not affected by salt stress and has even been increased for tetraploid Cleopatra mandarin. Ion contents investigation has shown lower accumulations of chloride ions in leaves of the tetraploid plants when compared to diploid plants. Our results suggest that citrus tetraploid rootstocks are more tolerant to salt stress than their corresponding diploid. PMID:18722990

  6. Exploration for the salt stress tolerance genes from a salt-treated halophyte, Suaeda asparagoides.

    PubMed

    Ayarpadikannan, Selvam; Chung, Eunsook; Cho, Chang-Woo; So, Hyun-Ah; Kim, Soon-Ok; Jeon, Joo-Min; Kwak, Myoung-Hae; Lee, Seon-Woo; Lee, Jai-Heon

    2012-01-01

    Salinity stress severely affects plant growth and development causing crop loss worldwide. Suaeda asparagoides is a salt-marsh euhalophyte widely distributed in southwestern foreshore of Korea. To isolate salt tolerance genes from S. asparagoides, we constructed a cDNA library from leaf tissues of S. asparagoides that was treated with 200 mM NaCl. A total of 1,056 clones were randomly selected for EST sequencing, and 932 of them produced readable sequence. By sequence analysis, we identified 538 unigenes and registered each in National Center for Biotechnology Information. The 80 salt stress related genes were selected to study their differential expression. Reverse transcription-PCR and Northern blot analysis revealed that 23 genes were differentially expressed under the high salinity stress conditions in S. asparagoides. They are functionally diverse including transport, signal transduction, transcription factor, metabolism and stress associated protein, and unknown function. Among them dehydrin (SaDhn) and RNA binding protein (SaRBP1) were examined for their abiotic stress tolerance in yeast (Saccharomyces cerevisiae). Yeast overexpressing SaDhn and SaRBP1 showed enhanced tolerance to osmotic, freezing and heat shock stresses. This study provides the evidence that SaRBP1 and SaDhn from S. asparagoides exert abiotic stress tolerance in yeast. Information of salt stress related genes from S. asparagoides would contribute for the accumulating genetic resources to improve osmotic tolerance in plants. PMID:21874516

  7. Salt tolerances of some mainland tree species select as through nursery screening.

    PubMed

    Miah, Md Abdul Quddus

    2013-09-15

    A study of salt tolerance was carried out on germination, survival and height growth performance of important mesophytic species such as Acacia auriculiformis, Acacia hybrid, Artocarpus heterophyllus, Albizia procera, Albizia lebbeck, Acacia nilotica, Achras sapota, Casuarina equisetifolaia, Emblica officinalis, Leucaena leucocephala, Samania saman, Swetenia macrophylla, Terminalia arjuna, Tamarindus indica, Terminalia bellirica and Thespesia populnea in nursery stage using fresh water and salt (NaCl) solutions of 10, 15 and 20 ppm. Effect of salt on germination, survival performance and height growth performance were examined in this condition. Based on the observation, salt tolerance of these species has been determined Acacia auriculiformis, Acacia hybrid, Achras sapota, Casuarina equisetifolia, Leucaena leucocephala and Tamarindus indica has showed the best capacity to perform in different salinity conditions. Acacia nilotica, Emblica officinalis, Thespesia populnea has performed better. Albizia procera, Samania saman and Terminalia bellirica, germination and height performance showed good but when salinity increases survivability were decreases. PMID:24502152

  8. Screening of Purslane (Portulaca oleracea L.) Accessions for High Salt Tolerance

    PubMed Central

    Juraimi, Abdul Shukor; Rafii, M. Y.; Abdul Hamid, Azizah

    2014-01-01

    Purslane (Portulaca oleracea L.) is an herbaceous leafy vegetable crop, comparatively more salt-tolerant than any other vegetables with high antioxidants, minerals, and vitamins. Salt-tolerant crop variety development is of importance due to inadequate cultivable land and escalating salinity together with population pressure. In this view a total of 25 purslane accessions were initially selected from 45 collected purslane accessions based on better growth performance and subjected to 5 different salinity levels, that is, 0.0, 10.0, 20.0, 30.0, and 40.0 dS m−1 NaCl. Plant height, number of leaves, number of flowers, and dry matter contents in salt treated purslane accessions were significantly reduced (P ≤ 0.05) and the enormity of reduction increased with increasing salinity stress. Based on dry matter yield reduction, among all 25 purslane accessions 2 accessions were graded as tolerant (Ac7 and Ac9), 6 accessions were moderately tolerant (Ac3, Ac5, Ac6, Ac10, Ac11, and Ac12), 5 accessions were moderately susceptible (Ac1, Ac2, Ac4, Ac8, and Ac13), and the remaining 12 accessions were susceptible to salinity stress and discarded from further study. The selected 13 purslane accessions could assist in the identification of superior genes for salt tolerance in purslane for improving its productivity and sustainable agricultural production. PMID:25003141

  9. Overexpression of Late Embryogenesis Abundant 14 enhances Arabidopsis salt stress tolerance

    SciTech Connect

    Jia, Fengjuan Qi, Shengdong Li, Hui Liu, Pu Li, Pengcheng Wu, Changai Zheng, Chengchao Huang, Jinguang

    2014-11-28

    Highlights: • It is the first time to investigate the biological function of AtLEA14 in salt stress response. • AtLEA14 enhances the salt stress tolerance both in Arabidopsis and yeast. • AtLEA14 responses to salt stress by stabilizing AtPP2-B11, an E3 ligase, under normal or salt stress conditions. - Abstract: Late embryogenesis abundant (LEA) proteins are implicated in various abiotic stresses in higher plants. In this study, we identified a LEA protein from Arabidopsis thaliana, AtLEA14, which was ubiquitously expressed in different tissues and remarkably induced with increased duration of salt treatment. Subcellular distribution analysis demonstrated that AtLEA14 was mainly localized in the cytoplasm. Transgenic Arabidopsis and yeast overexpressing AtLEA14 all exhibited enhanced tolerance to high salinity. The transcripts of salt stress-responsive marker genes (COR15a, KIN1, RD29B and ERD10) were overactivated in AtLEA14 overexpressing lines compared with those in wild type plants under normal or salt stress conditions. In vivo and in vitro analysis showed that AtLEA14 could effectively stabilize AtPP2-B11, an important E3 ligase. These results suggested that AtLEA14 had important protective functions under salt stress conditions in Arabidopsis.

  10. Over-expression of a tomato N-acetyl-L-glutamate synthase gene (SlNAGS1) in Arabidopsis thaliana results in high ornithine levels and increased tolerance in salt and drought stresses

    PubMed Central

    Kalamaki, Mary S.; Alexandrou, Dimitris; Lazari, Diamanto; Merkouropoulos, Georgios; Fotopoulos, Vasileios; Pateraki, Irene; Aggelis, Alexandros; Carrillo-López, Armando; Rubio-Cabetas, Maria J.; Kanellis, Angelos K.

    2009-01-01

    A single copy of the N-acetyl-L-glutamate synthase gene (SlNAGS1) has been isolated from tomato. The deduced amino acid sequence consists of 604 amino acids and shows a high level of similarity to the predicted Arabidopsis NAGS1 and NAGS2 proteins. Furthermore, the N-terminus ArgB domain and the C-terminus ArgA domain found in SlNAGS1 are similar to the structural arrangements that have been reported for other predicted NAGS proteins. SlNAGS1 was expressed at high levels in all aerial organs, and at basic levels in seeds, whereas it was not detected at all in roots. SlNAGS1 transcript accumulation was noticed transiently in tomato fruit at the red-fruit stage. In addition, an increase of SlNAGS1 transcripts was detected in mature green tomato fruit within the first hour of exposure to low oxygen concentrations. Transgenic Arabidopsis plants have been generated expressing the SlNAGS1 gene under the control of the cauliflower mosaic virus (CaMV) 35S promoter. Three homozygous transgenic lines expressing the transgene (lines 1-7, 3-8, and 6-5) were evaluated further. All three transgenic lines showed a significant accumulation of ornithine in the leaves with line 3-8 exhibiting the highest concentration. The same lines demonstrated higher germination ability compared to wild-type (WT) plants when subjected to 250 mM NaCl. Similarly, mature plants of all three transgenic lines displayed a higher tolerance to salt and drought stress compared to WT plants. Under most experimental conditions, transgenic line 3-8 performed best, while the responses obtained from lines 1-7 and 6-5 depended on the applied stimulus. To our knowledge, this is the first plant NAGS gene to be isolated, characterized, and genetically modified. PMID:19357433

  11. Over-expression of a tomato N-acetyl-L-glutamate synthase gene (SlNAGS1) in Arabidopsis thaliana results in high ornithine levels and increased tolerance in salt and drought stresses.

    PubMed

    Kalamaki, Mary S; Alexandrou, Dimitris; Lazari, Diamanto; Merkouropoulos, Georgios; Fotopoulos, Vasileios; Pateraki, Irene; Aggelis, Alexandros; Carrillo-López, Armando; Rubio-Cabetas, Maria J; Kanellis, Angelos K

    2009-01-01

    A single copy of the N-acetyl-L-glutamate synthase gene (SlNAGS1) has been isolated from tomato. The deduced amino acid sequence consists of 604 amino acids and shows a high level of similarity to the predicted Arabidopsis NAGS1 and NAGS2 proteins. Furthermore, the N-terminus ArgB domain and the C-terminus ArgA domain found in SlNAGS1 are similar to the structural arrangements that have been reported for other predicted NAGS proteins. SlNAGS1 was expressed at high levels in all aerial organs, and at basic levels in seeds, whereas it was not detected at all in roots. SlNAGS1 transcript accumulation was noticed transiently in tomato fruit at the red-fruit stage. In addition, an increase of SlNAGS1 transcripts was detected in mature green tomato fruit within the first hour of exposure to low oxygen concentrations. Transgenic Arabidopsis plants have been generated expressing the SlNAGS1 gene under the control of the cauliflower mosaic virus (CaMV) 35S promoter. Three homozygous transgenic lines expressing the transgene (lines 1-7, 3-8, and 6-5) were evaluated further. All three transgenic lines showed a significant accumulation of ornithine in the leaves with line 3-8 exhibiting the highest concentration. The same lines demonstrated higher germination ability compared to wild-type (WT) plants when subjected to 250 mM NaCl. Similarly, mature plants of all three transgenic lines displayed a higher tolerance to salt and drought stress compared to WT plants. Under most experimental conditions, transgenic line 3-8 performed best, while the responses obtained from lines 1-7 and 6-5 depended on the applied stimulus. To our knowledge, this is the first plant NAGS gene to be isolated, characterized, and genetically modified. PMID:19357433

  12. Induced maize salt tolerance by rhizosphere inoculation of Bacillus amyloliquefaciens SQR9.

    PubMed

    Chen, Lin; Liu, Yunpeng; Wu, Gengwei; Veronican Njeri, Kimani; Shen, Qirong; Zhang, Nan; Zhang, Ruifu

    2016-09-01

    Salt stress reduces plant growth and is now becoming one of the most important factors restricting agricultural productivity. Inoculation of plant growth-promoting rhizobacteria (PGPR) has been shown to confer plant tolerance against abiotic stress, but the detailed mechanisms of how this occurs remain unclear. In this study, hydroponic experiments indicated that the PGPR strain Bacillus amyloliquefaciens SQR9 could help maize plants tolerate salt stress. After exposure to salt stress for 20 days, SQR9 significantly promoted the growth of maize seedlings and enhanced the chlorophyll content compared with the control. Additional analysis showed that the involved mechanisms could be the enhanced total soluble sugar content for decreasing cell destruction, improved peroxidase/catalase activity and glutathione content for scavenging reactive oxygen species, and reduced Na(+) levels in the plant to decrease Na(+) toxicity. These physiological appearances were further confirmed by the upregulation of RBCS, RBCL, H(+) -PPase, HKT1, NHX1, NHX2 and NHX3, as well as downregulation of NCED expression, as determined by quantitative reverse transcription-polymerase chain reaction. However, SQR9 counteracted the increase of abscisic acid in response to salt stress. In summary, these results show that SQR9 confers plant salt tolerance by protecting the plant cells and managing Na(+) homeostasis. Hence, it can be used in salt stress prone areas, thereby promoting agricultural production. PMID:26932244

  13. Physiological and molecular characterization of the enhanced salt tolerance induced by low-dose gamma irradiation in Arabidopsis seedlings

    SciTech Connect

    Qi, Wencai; Zhang, Liang; Xu, Hangbo; Wang, Lin; Jiao, Zhen

    2014-07-25

    Highlights: • 50-Gy gamma irradiation markedly promotes the seedling growth under salt stress in Arabidopsis. • The contents of H{sub 2}O{sub 2} and MDA are obviously reduced by low-dose gamma irradiation under salt stress. • Low-dose gamma irradiation stimulates the activities of antioxidant enzymes under salt stress. • Proline accumulation is required for the low-gamma-ray-induced salt tolerance. • Low gamma rays differentially regulate the expression of genes related to salt stress. - Abstract: It has been established that gamma rays at low doses stimulate the tolerance to salt stress in plants. However, our knowledge regarding the molecular mechanism underlying the enhanced salt tolerance remains limited. In this study, we found that 50-Gy gamma irradiation presented maximal beneficial effects on germination index and root length in response to salt stress in Arabidopsis seedlings. The contents of H{sub 2}O{sub 2} and MDA in irradiated seedlings under salt stress were significantly lower than those of controls. The activities of antioxidant enzymes and proline levels in the irradiated seedlings were markedly increased compared with the controls. Furthermore, transcriptional expression analysis of selected genes revealed that some components of salt stress signaling pathways were stimulated by low-dose gamma irradiation under salt stress. Our results suggest that gamma irradiation at low doses alleviates the salt stress probably by modulating the physiological responses as well as stimulating the stress signal transduction in Arabidopsis seedlings.

  14. Transgenic salt-tolerant tomato plants accumulate salt in foliage but not in fruit.

    PubMed

    Zhang, H X; Blumwald, E

    2001-08-01

    Transgenic tomato plants overexpressing a vacuolar Na+/H+ antiport were able to grow, flower, and produce fruit in the presence of 200 mM sodium chloride. Although the leaves accumulated high sodium concentrations, the tomato fruit displayed very low sodium content. Contrary to the notion that multiple traits introduced by breeding into crop plants are needed to obtain salt-tolerant plants, the modification of a single trait significantly improved the salinity tolerance of this crop plant. These results demonstrate that with a combination of breeding and transgenic plants it could be possible to produce salt-tolerant crops with far fewer target traits than had been anticipated. The accumulation of sodium in the leaves and not in the fruit demonstrates the utility of such a modification in preserving the quality of the fruit. PMID:11479571

  15. Acclimation improves salt stress tolerance in Zea mays plants.

    PubMed

    Pandolfi, Camilla; Azzarello, Elisa; Mancuso, Stefano; Shabala, Sergey

    2016-08-20

    Plants exposure to low level salinity activates an array of processes leading to an improvement of plant stress tolerance. Although the beneficial effect of acclimation was demonstrated in many herbaceous species, underlying mechanisms behind this phenomenon remain poorly understood. In the present study we have addressed this issue by investigating ionic mechanisms underlying the process of plant acclimation to salinity stress in Zea mays. Effect of acclimation were examined in two parallel sets of experiments: a growth experiment for agronomic assessments, sap analysis, stomatal conductance, chlorophyll content, and confocal laser scanning imaging; and a lab experiment for in vivo ion flux measurements from root tissues. Being exposed to salinity, acclimated plants (1) retain more K(+) but accumulate less Na(+) in roots; (2) have better vacuolar Na(+) sequestration ability in leaves and thus are capable of accumulating larger amounts of Na(+) in the shoot without having any detrimental effect on leaf photochemistry; and (3) rely more on Na(+) for osmotic adjustment in the shoot. At the same time, acclimation affect was not related in increased root Na(+) exclusion ability. It appears that even in a such salt-sensitive species as maize, Na(+) exclusion from uptake is of a much less importance compared with the efficient vacuolar Na(+) sequestration in the shoot. PMID:27372277

  16. Relationship between Salt Tolerance and Resistance to Polyethylene Glycol-Induced Water Stress in Cultured Citrus Cells 1

    PubMed Central

    Ben-Hayyim, Gozal

    1987-01-01

    Salt-tolerant selected cells of Shamouti orange (Citrus sinensis) and Sour orange (Citrus aurantium) grew considerably better than nonselected cells at any NaCl concentration tested up to 200 millimolar. Also, the growth response of each treatment was identical in the two species. However, the performance of cells of the two species under osmotic stress induced by polyethylene glycol (PEG), which is presumably a nonabsorbed osmoticum, was significantly different. The nonselected Shamouti cell lines were significantly more sensitive to osmotic stress than the selected cells. The salt adapted Shamouti cells were apparently also adapted to osmotic stress induced by PEG. In Sour orange, however, the selected lines had no advantage over the nonselected line in response to osmotic stress induced by PEG. This response was also similar quantitatively to the response of the selected salt-tolerant Shamouti cell line. It seems that the tolerance to salt in Shamouti, a partial salt excluder, involves an osmotic adaptation, whereas in Sour orange, a salt accumulator, such an adaptation apparently does not occur. PEG-induced osmotic stress causes an increase in the percent dry weight of salt-sensitive and salt-tolerant cells of both species. No such increase was found under salt stress. The size of control and stressed cells is not significantly different. PMID:16665715

  17. Selenium accumulation and selenium-salt co-tolerance in five grass species. [Festuca arundinaceae; Agropyron deserorum; Buchloe dactyloides; Agrostis stolonifera; Cynodon dactylon

    SciTech Connect

    Wu, L.; Huang, Z.; Burau, R.G.

    1987-04-01

    Five grass species including Tall fescue (Festuca arundinaceae Schred), Crested wheatgrass (Agropyron deserorum Fisch), Buffalo grass (Buchlor dactyloides (Nutt.) Engelm.), Seaside bentgrass (Agrostis stolonifera L.) and Bermuda grass (Cynodon dactylon (L.) Pers., Syn.) were examined for selenium and salt tolerance and selenium accumulation under solution culture conditions. Distinct differences in both selenium and salt tolerance were detected among the five species, but no direct association between selenium and salt resistance was found. Tall fescue displayed considerable tolerance under 1 ppm selenium and 100 mM salt treatment. Combined selenium and salt treatment revealed that selenium uptake was increased by the incorporation of salt in the culture solution. However, salt uptake was not significantly affected by the presence of selenium in the culture solution. At moderate toxic levels of selenium, the species with greater tolerance accumulated less selenium than did the less tolerant species.

  18. Educational Strategies to Increase Racial Tolerance.

    ERIC Educational Resources Information Center

    Buchignani, Norman

    This paper reviews the effectiveness and practicality of various educational approaches for increasing racial tolerance and calls for developing strategies that have been formally evaluated to avoid the waste of time and limited resources. The first section discusses the racial inadequacies of most programs which purport to affect racial…

  19. The bioenergetics of salt tolerance: Final report (2)

    SciTech Connect

    Lanyi, J.K.

    1986-10-28

    Studies on the physiology and molecular mechanism of light-driven chloride transport by halorhodopsin in the halobacteria are described. These studies focus on the ion-transport ATPase of halobacteria and the respiration-linked sodium transport system of the halotolerant bacterium, Bal. The results have provided insights into the role and functioning of ionic pumps. Chloride transport was shown to be an integral component of the overall ion circulation in halobacterial cells, one which maintains internal salt concentration and therefore cellular volume. A considerable amount of new information was gained about how halorhodopsin functions: its photointermediates, the nature of chloride-binding sites, the role of the deprotonation of the retinal Schiff-base, and how removal of most of the arginine residues affects (or rather, not affects) chloride-binding. Methods were adapted and developed for the study of membrane-bound halobacterial ATPase, its solubilization and (so far) partial purification. It was shown that in the salt-tolerant pseudomonad, Bal, the sodium-sensitive step in the respiratory chain is at the reduction of the semiquinone to quinol, as in another unrelated, but also salt-tolerant, marine microorganism. 17 refs., 1 fig.

  20. The bioenergetics of salt tolerance: Final report (Irvine Laboratory)

    SciTech Connect

    Lanyi, J.K.

    1986-10-28

    We have studied the physiology and molecular mechanism of light-driven chloride transport by halorhodopsin in the halobacteria, and initiated work in the ion-transport ATPase of halobacteria and the respiration-linked sodium transport system of the halotolerant bacterium, Bal. The results have provided insights into the role and functioning of ionic pumps. Chloride transport was shownto be an integral component of the overall ion circulation in halobacterial cells, one which maintains internal salt concentration and therefore cellular volume. How halorhodopsin functions; its photointermediates, the nature of chloride-binding sites, the role of the deprotonation of the retinal Schiff-base, and how removal of most of the arginine residues affects chloride-binding were investigated. Methods were adapted and developed for the study of membrane-bound halobacterial ATPase, its solubilization and partial purification. It was shown that in the salt-tolerant pseudomonad, Bal, the sodium-sensitive step in the respiratory chain is at the reduction of the semiquinone to quinol, as in another unrelated, but also salt-tolerant, marine microorganism. 10 refs., 1 fig.

  1. Salt tolerance and stress level affect plant biomass-density relationships and neighbor effects

    NASA Astrophysics Data System (ADS)

    Yu, Zhenxing; Chen, Wenwen; Zhang, Qian; Yang, Haishui; Tang, Jianjun; Weiner, Jacob; Chen, Xin

    2014-07-01

    It has been shown that plant biomass-density relationships are altered under extreme or stressed conditions. We do not know whether variation in biomass-density relationships is a direct result of stress tolerance or occurs via changes in plant-plant interactions. Here, we evaluated biomass-density relationships and neighbor effects in six plant species that differ in salt tolerance in a salt marsh, and conducted a literature review of biomass-density relationship under higher and lower stress levels. Our field study showed that both neighbor effects and the exponent of the biomass-density relationship (α) varied among plant species with different degrees of salt tolerance. There was a positive relationship between neighbor effects (measured as relative interaction index) and α-value among the tested species. The literature review showed that α and its variation increased under higher stress. Our results indicate that plant species with different salinity tolerance differ in the direction and strength of neighbor effects, resulting in variation in biomass-density relationships. Our results support the hypothesis that differences in biomass-density relationships among species are not due to differences in stress tolerance alone, they are mediated by changes in plant-plant interactions.

  2. Over-expression of PsGPD, a mushroom glyceraldehyde-3-phosphate dehydrogenase gene, enhances salt tolerance in rice plants.

    PubMed

    Cho, Jung-Il; Lim, Hye-Min; Siddiqui, Zamin Shaheed; Park, Sung-Han; Kim, A-Ram; Kwon, Taek-Ryoun; Lee, Seong-Kon; Park, Soo-Chul; Jeong, Mi-Jeong; Lee, Gang-Seob

    2014-08-01

    Transgenic potatoes expressing glyceraldehyde-3-phosphate dehydrogenase (GPD), isolated from the oyster mushroom, Pleurotus sajor-caju, had increased tolerance to salt stress (Jeong et al. Biochem Biophys Res Commun 278:192-196, 2000). To examine the physiological mechanisms enhancing salt tolerance in GPD-transgenic rice plants, the salt tolerance of five GPD transgenic rice lines (T1-T5) derived from Dongjin rice cultivar were evaluated in a fixed 150 mM saline environment in comparison to two known wild-type rice cultivars, Dongjin (salt sensitive) and Pokali (salt tolerant). Transgenic lines, T2, T3, and T5, had a substantial increase in biomass and relative water content compared to Dongjin. Stomatal conductance and osmotic potential were higher in the GPD transgenic lines and were similar to those in Pokali. The results are discussed based on the comparative physiological response of GPD transgenic lines with those of the salt-sensitive and salt-tolerant rice cultivars. PMID:24737077

  3. Soybean Salt Tolerance 1 (GmST1) Reduces ROS Production, Enhances ABA Sensitivity, and Abiotic Stress Tolerance in Arabidopsis thaliana.

    PubMed

    Ren, Shuxin; Lyle, Chimera; Jiang, Guo-Liang; Penumala, Abhishek

    2016-01-01

    Abiotic stresses, including high soil salinity, significantly reduce crop production worldwide. Salt tolerance in plants is a complex trait and is regulated by multiple mechanisms. Understanding the mechanisms and dissecting the components on their regulatory pathways will provide new insights, leading to novel strategies for the improvement of salt tolerance in agricultural and economic crops of importance. Here we report that soybean salt tolerance 1, named GmST1, exhibited strong tolerance to salt stress in the Arabidopsis transgenic lines. The GmST1-overexpressed Arabidopsis also increased sensitivity to ABA and decreased production of reactive oxygen species under salt stress. In addition, GmST1 significantly improved drought tolerance in Arabidopsis transgenic lines. GmST1 belongs to a 3-prime part of Glyma.03g171600 gene in the current version of soybean genome sequence annotation. However, comparative reverse transcription-polymerase chain reaction analysis around Glyma.03g171600 genomic region confirmed that GmST1 might serve as an intact gene in soybean leaf tissues. Unlike Glyma.03g171600 which was not expressed in leaves, GmST1 was strongly induced by salt treatment in the leaf tissues. By promoter analysis, a TATA box was detected to be positioned close to GmST1 start codon and a putative ABRE and a DRE cis-acting elements were identified at about 1 kb upstream of GmST1 gene. The data also indicated that GmST1-transgenic lines survived under drought stress and showed a significantly lower water loss than non-transgenic lines. In summary, our results suggest that overexpression of GmST1 significantly improves Arabidopsis tolerance to both salt and drought stresses and the gene may be a potential candidate for genetic engineering of salt- and drought-tolerant crops. PMID:27148284

  4. Soybean Salt Tolerance 1 (GmST1) Reduces ROS Production, Enhances ABA Sensitivity, and Abiotic Stress Tolerance in Arabidopsis thaliana

    PubMed Central

    Ren, Shuxin; Lyle, Chimera; Jiang, Guo-liang; Penumala, Abhishek

    2016-01-01

    Abiotic stresses, including high soil salinity, significantly reduce crop production worldwide. Salt tolerance in plants is a complex trait and is regulated by multiple mechanisms. Understanding the mechanisms and dissecting the components on their regulatory pathways will provide new insights, leading to novel strategies for the improvement of salt tolerance in agricultural and economic crops of importance. Here we report that soybean salt tolerance 1, named GmST1, exhibited strong tolerance to salt stress in the Arabidopsis transgenic lines. The GmST1-overexpressed Arabidopsis also increased sensitivity to ABA and decreased production of reactive oxygen species under salt stress. In addition, GmST1 significantly improved drought tolerance in Arabidopsis transgenic lines. GmST1 belongs to a 3-prime part of Glyma.03g171600 gene in the current version of soybean genome sequence annotation. However, comparative reverse transcription-polymerase chain reaction analysis around Glyma.03g171600 genomic region confirmed that GmST1 might serve as an intact gene in soybean leaf tissues. Unlike Glyma.03g171600 which was not expressed in leaves, GmST1 was strongly induced by salt treatment in the leaf tissues. By promoter analysis, a TATA box was detected to be positioned close to GmST1 start codon and a putative ABRE and a DRE cis-acting elements were identified at about 1 kb upstream of GmST1 gene. The data also indicated that GmST1-transgenic lines survived under drought stress and showed a significantly lower water loss than non-transgenic lines. In summary, our results suggest that overexpression of GmST1 significantly improves Arabidopsis tolerance to both salt and drought stresses and the gene may be a potential candidate for genetic engineering of salt- and drought-tolerant crops. PMID:27148284

  5. 40 CFR 180.383 - Sodium salt of acifluorfen; tolerances for residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Sodium salt of acifluorfen; tolerances for residues. 180.383 Section 180.383 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.383 Sodium salt of...

  6. 40 CFR 180.383 - Sodium salt of acifluorfen; tolerances for residues.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Sodium salt of acifluorfen; tolerances for residues. 180.383 Section 180.383 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.383 Sodium salt of...

  7. Interpopulation differences in the salt tolerance of two Cladophora species

    NASA Astrophysics Data System (ADS)

    Thomas, D. N.; Collins, J. C.; Russell, G.

    1990-02-01

    The effects of changes in external salinity upon Baltic and U.K. populations of Cladophora rupestris (L) Kütz and C. glomerata (L) Kütz have been studied. Rates of net photosynthesis after salinity treatment (0-102‰) were used as a measure of salinity tolerance. There were very pronounced differences in the salt tolerance of the two C. glomerata populations, whereas Baltic and U.K. C. rupestris differed significantly only in responses to extreme hyposaline treatment. The effect of salinity on the thallus content of K + and Na + was measured. There were significant differences in the ratios of these ions in populations of both species. The populations also differed significantly in the dimensions of their cells and cellular volume.

  8. Stress Tolerance Profiling of a Collection of Extant Salt-Tolerant Rice Varieties and Transgenic Plants Overexpressing Abiotic Stress Tolerance Genes.

    PubMed

    Kurotani, Ken-ichi; Yamanaka, Kazumasa; Toda, Yosuke; Ogawa, Daisuke; Tanaka, Maiko; Kozawa, Hirotsugu; Nakamura, Hidemitsu; Hakata, Makoto; Ichikawa, Hiroaki; Hattori, Tsukaho; Takeda, Shin

    2015-10-01

    Environmental stress tolerance is an important trait for crop improvement. In recent decades, numerous genes that confer tolerance to abiotic stress such as salinity were reported. However, the levels of salt tolerance differ greatly depending on growth conditions, and mechanisms underlying the complicated nature of stress tolerance are far from being fully understood. In this study, we investigated the profiles of stress tolerance of nine salt-tolerant rice varieties and transgenic rice lines carrying constitutively expressed genes that are potentially involved in salt tolerance, by evaluating their growth and viability under salt, heat, ionic and hyperosmotic stress conditions. Profiling of the extant varieties and selected chromosome segment substitution lines showed that salt tolerance in a greenhouse condition was more tightly correlated with ionic stress tolerance than osmotic stresses. In Nona Bokra, one of the most salt-tolerant varieties, the contribution of the previously identified sodium transporter HKT1;5 to salt tolerance was fairly limited. In addition, Nona Bokra exhibited high tolerance to all the stresses imposed. More surprisingly, comparative evaluation of 74 stress tolerance genes revealed that the most striking effect to enhance salt tolerance was conferred by overexpressing CYP94C2b, which promotes deactivation of jasmonate. In contrast, genes encoding ABA signaling factors conferred multiple stress tolerance. Genes conferring tolerance to both heat and hyperosmotic stresses were preferentially linked to functional categories related to heat shock proteins, scavenging of reactive oxygen species and Ca(2+) signaling. These comparative profiling data provide a new basis for understanding the ability of plants to grow under harsh environmental conditions. PMID:26329877

  9. Regulation of nitrogen metabolism in salt tolerant and salt sensitive Frankia strains.

    PubMed

    Srivastava, Amrita; Mishra, Arun Kumar

    2014-04-01

    Effect of salinity (0, 50, 100, 250, 500 and 750 mM NaCI) was observed on some important physiological parameters of nitrogen metabolism such as nitrate uptake, intracellular and extracellular ammonium status and activities of nitrogenase, nitrate reductase, nitrite reductase and glutamine synthetase among Frankia strains differing in their salt tolerance capacity. Nitrogenase activity closely followed the growth pattern with regular decline on NaCI supplementation. All the other enzymes showed optimum activity at 100 mM and declined further. Co-regulation of the nitrate uptake system and sequential enzyme activities plays a crucial role in governing the nitrogen status of strains during salt stress. HsIil0 experiencing minimum decline in enzyme activities and best possible nitrogen regulation under NaC1 replete condition showed adequate nutritional management. Among all the strains, HsIil0 proved to be salt tolerant on account of above features while the salt sensitive strain HsIi8 lacked the ability to regulate various steps of nitrogen metabolism during salinity, and thus Frankia strain HsIil0 can potentially serve as a potential biofertilizer in the saline soil. PMID:24772938

  10. Evaluation of a Simple Method to Screen Soybean Genotypes for Salt Tolerance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Excessive salt can reduce soybean yield in grower fields. Salt tolerant cultivars are needed to prevent field yield losses where excess salt is a problem. Soybean genotypes have primarily been evaluated for reaction to salt in the greenhouse using a labor intensive and costly hydroponics method. ...

  11. Populus euphratica HSF binds the promoter of WRKY1 to enhance salt tolerance.

    PubMed

    Shen, Zedan; Yao, Jun; Sun, Jian; Chang, Liwei; Wang, Shaojie; Ding, Mingquan; Qian, Zeyong; Zhang, Huilong; Zhao, Nan; Sa, Gang; Hou, Peichen; Lang, Tao; Wang, Feifei; Zhao, Rui; Shen, Xin; Chen, Shaoliang

    2015-06-01

    Poplar species increase expressions of transcription factors to deal with salt environments. We assessed the salt-induced transcriptional responses of heat-shock transcription factor (HSF) and WRKY1 in Populus euphratica, and their roles in salt tolerance. High NaCl (200mM) induced PeHSF and PeWRKY1 expressions in P. euphratica, with a rapid rise in roots than in leaves. Moreover, the salt-elicited PeHSF reached its peak level 6h earlier than PeWRKY1 in leaves. PeWRKY1 was down-regulated in salinized P. euphratica when PeHSF was silenced by tobacco rattle virus-based gene silencing. Subcellular assays in onion epidermal cells and Arabidopsis protoplasts revealed that PeHSF and PeWRKY1 were restricted to the nucleus. Transgenic tobacco plants overexpressing PeWRKY1 showed improved salt tolerance in terms of survival rate, root growth, photosynthesis, and ion fluxes. We further isolated an 1182-bp promoter fragment upstream of the translational start of PeWRKY1 from P. euphratica. Promoter sequence analysis revealed that PeWRKY1 harbours four tandem repeats of heat shock element (HSE) in the upstream regulatory region. Yeast one-hybrid assay showed that PeHSF directly binds the cis-acting HSE. To determine whether the HSE cluster was important for salt-induced PeWRKY1 expression, the promoter-reporter construct PeWRKY1-pro::GUS was transferred to tobacco plants. β-glucuronidase activities increased in root, leaf, and stem tissues under salt stress. Therefore, we conclude that salinity increased PeHSF transcription in P. euphratica, and that PeHSF binds the cis-acting HSE of the PeWRKY1 promoter, thus activating PeWRKY1 expression. PMID:25900569

  12. OsHKT2;2/1-mediated Na(+) influx over K(+) uptake in roots potentially increases toxic Na(+) accumulation in a salt-tolerant landrace of rice Nona Bokra upon salinity stress.

    PubMed

    Suzuki, Kei; Costa, Alex; Nakayama, Hideki; Katsuhara, Maki; Shinmyo, Atsuhiko; Horie, Tomoaki

    2016-01-01

    HKT transporters are Na(+)-permeable membrane proteins, which mediate Na(+) and K(+) homeostasis in K(+)-depleted and saline environments in plants. Class II HKT transporters, a distinct subgroup found predominantly in monocots, are known to mediate Na(+)-K(+) co-transport in principle. Here we report features of ion transport functions of No-OsHKT2;2/1, a class II transporter identified in a salt tolerant landrace of indica rice, Nona Bokra. We profiled No-OsHKT2;2/1 expression in organs of Nona Bokra plants with or without salinity stress. Dominant accumulation of the No-OsHKT2;2/1 transcript in K(+)-starved roots of Nona Bokra plants largely disappeared in response to 50 mM NaCl. We found that No-OsHKT2;2/1 expressed in the high-affinity K(+) uptake deficient mutant of Saccharomyces cerevisiae and Xenopus laevis oocytes shows robust K(+) selectivity even in the presence of a large amount of NaCl as reported previously. However, No-OsHKT2;2/1-expressing yeast cells exhibited Na(+) hypersensitive growth under various concentrations of K(+) and Na(+) as the cells expressing Po-OsHKT2;2, a similar class II transporter from another salt tolerant indica rice Pokkali, when compared with the growth of cells harboring empty vector or cells expressing OsHKT2;4. The OsHKT2;4 protein expressed in Xenopus oocytes showed strong K(+) selectivity in the presence of 50 mM NaCl in comparison with No-OsHKT2;2/1 and Po-OsHKT2;2. Together with apparent plasma membrane-localization of No-OsHKT2;2/1, these results point to possibilities that No-OsHKT2;2/1 could mediate destructive Na(+) influx over K(+) uptake in Nona Bokra plants upon salinity stress, and that a predominant physiological function of No-OsHKT2;2/1 might be the acquisition of Na(+) and K(+) in K(+)-limited environments. PMID:26578190

  13. Arabidopsis ATAF1 enhances the tolerance to salt stress and ABA in transgenic rice.

    PubMed

    Liu, Yongchang; Sun, Jie; Wu, Yaorong

    2016-09-01

    NAC (NAM, ATAF1/2, CUC2) transcription factors are plant-specific and have diverse functions in many plant developmental processes and responses to stress. In our previous study, we found that the expression of ATAF1, an Arabidopsis NAC gene, was obviously induced by high-salinity and abscisic acid (ABA). The overexpression of ATAF1 in Arabidopsis increased plant sensitivity to ABA and salt. To investigate whether ATAF1 affects the sensitivity of monocotyledon plant to salt and ABA, ATAF1 transgenic rice were generated. Transgenic rice exhibited significantly improved salt tolerance and insensitivity to ABA. The results of real-time PCR showed that ATAF1 overexpression in rice elevated the transcription of OsLEA3, OsSalT1 and OsPM1, which are stress-associated genes. Our results indicate that ATAF1 plays an important role in response to salt stress and may be utilized to improve the salt tolerance of rice. PMID:27216423

  14. Proteomic study of a tolerant genotype of durum wheat under salt-stress conditions.

    PubMed

    Capriotti, Anna Laura; Borrelli, Grazia Maria; Colapicchioni, Valentina; Papa, Roberto; Piovesana, Susy; Samperi, Roberto; Stampachiacchiere, Serena; Laganà, Aldo

    2014-02-01

    Salinity is one of the major abiotic stress conditions limiting crop growth and productivity. Duilio is a wheat genotype that shows tolerant behavior in both salt-stress and drought-stress conditions. Toward better understanding of the biochemical response to salinity in this genotype of durum wheat, a comparative label-free shotgun proteomic analysis based on normalized spectral abundance factors was conducted on wheat leaf samples subjected to increasing salt-stress levels (100 and 200 mmol L(-1) NaCl) with respect to untreated samples. We found significant changes in 71 proteins for the first stress level, in 83 proteins at the higher salinity level, and in 88 proteins when comparing salt-stress levels with each other. The major changes concerned the proteins involved in primary metabolism and production of energy, followed by those involved in protein metabolism and cellular defense mechanisms. Some indications of different specific physiological and defense mechanisms implicated in increasing tolerance were obtained. The enhanced salinity tolerance in Duilio appeared to be governed by a higher capacity for osmotic homeostasis, a more efficient defense, and an improvement of protection from mechanical stress by increased cell wall lignifications, allowing a better potential for growth recovery. PMID:24337188

  15. A Novel Thylakoid Ascorbate Peroxidase from Jatrophacurcas Enhances Salt Tolerance in Transgenic Tobacco

    PubMed Central

    Liu, Zhibin; Bao, Han; Cai, Jin; Han, Jun; Zhou, Lirong

    2014-01-01

    Ascorbate peroxidase (APX) plays an important role in the metabolism of hydrogen peroxide in higher plants. In the present study, a novel APX gene (JctAPX) was cloned from Jatropha curcas L. The deduced amino acid sequence was similar to that of APX of some other plant species. JctAPX has a chloroplast transit peptide and was localized to the chloroplasts by analysis with a JctAPX-green fluorescent protein (GFP) fusion protein. Quantitative polymerase chain reaction (qPCR) analysis showed that JctAPX was constitutively expressed in different tissues from J. curcas and was upregulated by NaCl stress. To characterize its function in salt tolerance, the construct p35S: JctAPX was created and successfully introduced into tobacco by Agrobacterium-mediated transformation. Compared with wild type (WT), the transgenic plants exhibited no morphological abnormalities in the no-stress condition. However, under 200 mM NaCl treatment, JctAPX over-expressing plants showed increased tolerance to salt during seedling establishment and growth. In addition, the transgenic lines showed higher chlorophyll content and APX activity, which resulted in lower H2O2 content than WT when subjected to 400 mM NaCl stress. These results suggest that the increased APX activity in the chloroplasts from transformed plants increased salt tolerance by enhancing reactive oxygen species (ROS)-scavenging capacity under short-term NaCl stress conditions. PMID:24368517

  16. Yeast functional screen to identify genes conferring salt stress tolerance in Salicornia europaea

    PubMed Central

    Nakahara, Yoshiki; Sawabe, Shogo; Kainuma, Kenta; Katsuhara, Maki; Shibasaka, Mineo; Suzuki, Masanori; Yamamoto, Kosuke; Oguri, Suguru; Sakamoto, Hikaru

    2015-01-01

    Salinity is a critical environmental factor that adversely affects crop productivity. Halophytes have evolved various mechanisms to adapt to saline environments. Salicornia europaea L. is one of the most salt-tolerant plant species. It does not have special salt-secreting structures like a salt gland or salt bladder, and is therefore a good model for studying the common mechanisms underlying plant salt tolerance. To identify candidate genes encoding key proteins in the mediation of salt tolerance in S. europaea, we performed a functional screen of a cDNA library in yeast. The library was screened for genes that allowed the yeast to grow in the presence of 1.3 M NaCl. We obtained three full-length S. europaea genes that confer salt tolerance. The genes are predicted to encode (1) a novel protein highly homologous to thaumatin-like proteins, (2) a novel coiled-coil protein of unknown function, and (3) a novel short peptide of 32 residues. Exogenous application of a synthetic peptide corresponding to the 32 residues improved salt tolerance of Arabidopsis. The approach described in this report provides a rapid assay system for large-scale screening of S. europaea genes involved in salt stress tolerance and supports the identification of genes responsible for such mechanisms. These genes may be useful candidates for improving crop salt tolerance by genetic transformation. PMID:26579166

  17. Overexpression of NaKR3 enhances salt tolerance in Arabidopsis.

    PubMed

    Luo, Q; Zhao, Z; Li, D K; Zhang, Y; Xie, L F; Peng, M F; Yuan, S; Yang, Y

    2016-01-01

    Salinity is a major abiotic stress in agriculture. Here, we report that SODIUM POTASSIUM ROOT DEFECTIVE3 (NaKR3), which encodes a heavy metal-associated domain protein, is involved in salt tolerance in Arabidopsis. The results of quantitative reverse transcription-polymerase chain reaction analysis revealed that NaKR3 was induced by high salinity and osmotic stresses, but not by Cu(2+) stress. Transient expression of NaKR3-GFP in Arabidopsis protoplasts showed that the NaKR3 protein was localized in the cytosol. Transgenic Arabidopsis plants constitutively expressing NaKR3 under the control of the cauliflower mosaic virus 35S promoter exhibited increased tolerance to salt treatment. Furthermore, overexpression of NaKR3 increased the expression of SOS1 and SOS3, but decreased the accumulation of salt-induced proline. Taken together, our results indicate that NaKR3 is involved in the salt stress response in Arabidopsis. PMID:26909945

  18. An Ipomoea batatas Iron-Sulfur Cluster Scaffold Protein Gene, IbNFU1, Is Involved in Salt Tolerance

    PubMed Central

    Song, Xuejin; He, Shaozhen; Zhai, Hong; Liu, Qingchang

    2014-01-01

    Iron-sulfur cluster biosynthesis involving the nitrogen fixation (Nif) proteins has been proposed as a general mechanism acting in various organisms. NifU-like protein may play an important role in protecting plants against abiotic and biotic stresses. An iron-sulfur cluster scaffold protein gene, IbNFU1, was isolated from a salt-tolerant sweetpotato (Ipomoea batatas (L.) Lam.) line LM79 in our previous study, but its role in sweetpotato stress tolerance was not investigated. In the present study, the IbNFU1 gene was introduced into a salt-sensitive sweetpotato cv. Lizixiang to characterize its function in salt tolerance. The IbNFU1-overexpressing sweetpotato plants exhibited significantly higher salt tolerance compared with the wild-type. Proline and reduced ascorbate content were significantly increased, whereas malonaldehyde (MDA) content was significantly decreased in the transgenic plants. The activities of superoxide dismutase (SOD) and photosynthesis were significantly enhanced in the transgenic plants. H2O2 was also found to be significantly less accumulated in the transgenic plants than in the wild-type. Overexpression of IbNFU1 up-regulated pyrroline-5-carboxylate synthase (P5CS) and pyrroline-5-carboxylate reductase (P5CR) genes under salt stress. The systemic up-regulation of reactive oxygen species (ROS) scavenging genes was found in the transgenic plants under salt stress. These findings suggest that IbNFU1gene is involved in sweetpotato salt tolerance and enhances salt tolerance of the transgenic sweetpotato plants by regulating osmotic balance, protecting membrane integrity and photosynthesis and activating ROS scavenging system. PMID:24695556

  19. Salinity tolerance in soybean is modulated by natural variation in GmSALT3.

    PubMed

    Guan, Rongxia; Qu, Yue; Guo, Yong; Yu, Lili; Liu, Ying; Jiang, Jinghan; Chen, Jiangang; Ren, Yulong; Liu, Guangyu; Tian, Lei; Jin, Longguo; Liu, Zhangxiong; Hong, Huilong; Chang, Ruzhen; Gilliham, Matthew; Qiu, Lijuan

    2014-12-01

    The identification of genes that improve the salt tolerance of crops is essential for the effective utilization of saline soils for agriculture. Here, we use fine mapping in a soybean (Glycine max (L.) Merr.) population derived from the commercial cultivars Tiefeng 8 and 85-140 to identify GmSALT3 (salt tolerance-associated gene on chromosome 3), a dominant gene associated with limiting the accumulation of sodium ions (Na+) in shoots and a substantial enhancement in salt tolerance in soybean. GmSALT3 encodes a protein from the cation/H+ exchanger family that we localized to the endoplasmic reticulum and which is preferentially expressed in the salt-tolerant parent Tiefeng 8 within root cells associated with phloem and xylem. We identified in the salt-sensitive parent, 85-140, a 3.78-kb copia retrotransposon insertion in exon 3 of Gmsalt3 that truncates the transcript. By sequencing 31 soybean landraces and 22 wild soybean (Glycine soja) a total of nine haplotypes including two salt-tolerant haplotypes and seven salt-sensitive haplotypes were identified. By analysing the distribution of haplotypes among 172 Chinese soybean landraces and 57 wild soybean we found that haplotype 1 (H1, found in Tiefeng 8) was strongly associated with salt tolerance and is likely to be the ancestral allele. Alleles H2-H6, H8 and H9, which do not confer salinity tolerance, were acquired more recently. H1, unlike other alleles, has a wide geographical range including saline areas, which indicates it is maintained when required but its potent stress tolerance can be lost during natural selection and domestication. GmSALT3 is a gene associated with salt tolerance with great potential for soybean improvement. PMID:25292417

  20. Salicylic Acid Improved In Viro Meristem Regeneration and Salt Tolerance in Two Hibiscus Species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salicylic acid (SA) has been reported to induce abiotic stress, including salt tolerance in plants. The objective of this study was to determine whether application of various exogenous SA concentrations to in vitro grown meristem shoots could induce salt tolerance in two Hibiscus species. The effec...

  1. Improving salt tolerance in small grain crops using physiological genomics approaches

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The success in salt tolerance breeding has been limited in the past decades. The major reasons for the limited success are due to a) lack of reliable selection criteria, and b) environmental effects related to the complexity of the traits associated with salt tolerance. Previous research conducted a...

  2. The wheat MAP kinase phosphatase 1 alleviates salt stress and increases antioxidant activities in Arabidopsis.

    PubMed

    Zaidi, Ikram; Ebel, Chantal; Belgaroui, Nibras; Ghorbel, Mouna; Amara, Imène; Hanin, Moez

    2016-04-01

    Mitogen-activated protein kinase phosphatases (MKPs) are important negative regulators in the MAPK signaling pathways, which play crucial roles in plant growth, development and stress responses. We have previously shown that the heterologous expression of a durum wheat MKP, TMKP1, results in increased tolerance to salt stress in yeast but its particular contribution in salt stress tolerance in plants was not investigated. Here, TMKP1 was overexpressed in Arabidopsis thaliana and physiological changes were assessed in transgenic plants exposed to stress conditions. Under salt stress and especially LiCl, the TMKP1 overexpressors displayed higher germination rates in comparison to wild type plants. The enhancement of salt stress tolerance was accompanied by increased antioxidant enzyme activities, namely superoxide dismutase, catalase and peroxydases. Such increases in antioxidant activities were concomitant with lower malondialdehyde, superoxide anion O2(-) and hydrogen peroxide levels in the TMKP1 transgenic seedlings. Moreover, we provide evidence that, in contrast to the Arabidopsis ortholog AtMKP1, TMKP1 acts as a positive regulator of salt stress tolerance via its ectopic expression in the Arabidopsis mkp1 mutant. PMID:26927025

  3. Physiological and biochemical parameters for evaluation and clustering of rice cultivars differing in salt tolerance at seedling stage.

    PubMed

    Chunthaburee, Sumitahnun; Dongsansuk, Anoma; Sanitchon, Jirawat; Pattanagul, Wattana; Theerakulpisut, Piyada

    2016-07-01

    Salinity tolerance levels and physiological changes were evaluated for twelve rice cultivars, including four white rice and eight black glutinous rice cultivars, during their seedling stage in response to salinity stress at 100 mM NaCl. All the rice cultivars evaluated showed an apparent decrease in growth characteristics and chlorophyll accumulation under salinity stress. By contrast an increase in proline, hydrogen peroxide, peroxidase (POX) activity and anthocyanins were observed for all cultivars. The K(+)/Na(+) ratios evaluated for all rice cultivars were noted to be highly correlated with the salinity scores thus indicating that the K(+)/Na(+) ratio serves as a reliable indicator of salt stress tolerance in rice. Principal component analysis (PCA) based on physiological salt tolerance indexes could clearly distinguish rice cultivars into 4 salt tolerance clusters. Noteworthy, in comparison to the salt-sensitive ones, rice cultivars that possessed higher degrees of salt tolerance displayed more enhanced activity of catalase (CAT), a smaller increase in anthocyanin, hydrogen peroxide and proline content but a smaller drop in the K(+)/Na(+) ratio and chlorophyll accumulation. PMID:27298579

  4. A Cu/Zn superoxide dismutase from Jatropha curcas enhances salt tolerance of Arabidopsis thaliana.

    PubMed

    Liu, Z B; Zhang, W J; Gong, X D; Zhang, Q; Zhou, L R

    2015-01-01

    Superoxide dismutases (SODs) are involved in protecting plants against diverse biotic and abiotic stresses. In the present study, a novel Cu/Zn-SOD gene (JcCu/Zn-SOD) was cloned from Jatropha curcas L. Quantitative reverse transcription-polymerase chain reaction analysis revealed that JcCu/Zn-SOD is constitutively expressed in different tissues of J. curcas and induced under NaCl treatment. To characterize the function of this gene with respect to salt tolerance, the construct p35S:JcCu/Zn-SOD was developed and transformed into Arabidopsis using Agrobacterium-mediated transformation. Compared with wild-type, transgenic plants over-expressing JcCu/Zn-SOD showed enhanced tolerance to salt stress during germination, seedling establishment, and growth in terms of longer root, larger rosette area, and a larger number of leaves in addition to higher SOD activity levels under NaCl stress. In addition, over-expression of JcCu/Zn-SOD resulted in lower monodialdehyde content in transgenic Arabidopsis compared to wild-type plants under the same NaCl stress. Therefore, JcCu/Zn-SOD can increase a plant salt stress tolerance potentially by reducing oxidant injury. PMID:25867355

  5. Identification of two loci in tomato reveals distinct mechanisms for salt tolerance.

    PubMed

    Borsani, O; Cuartero, J; Fernández, J A; Valpuesta, V; Botella, M A

    2001-04-01

    Salt stress is one of the most serious environmental factors limiting the productivity of crop plants. To understand the molecular basis for salt responses, we used mutagenesis to identify plant genes required for salt tolerance in tomato. As a result, three tomato salt-hypersensitive (tss) mutants were isolated. These mutants defined two loci and were caused by single recessive nuclear mutations. The tss1 mutant is specifically hypersensitive to growth inhibition by Na(+) or Li(+) and is not hypersensitive to general osmotic stress. The tss2 mutant is hypersensitive to growth inhibition by Na(+) or Li(+) but, in contrast to tss1, is also hypersensitive to general osmotic stress. The TSS1 locus is necessary for K(+) nutrition because tss1 mutants are unable to grow on a culture medium containing low concentrations of K(+). Increased Ca(2)+ in the culture medium suppresses the growth defect of tss1 on low K(+). Measurements of membrane potential in apical root cells were made with an intracellular microelectrode to assess the permeability of the membrane to K(+) and Na(+). K(+)-dependent membrane potential measurements indicate impaired K(+) uptake in tss1 but not tss2, whereas no differences in Na(+) uptake were found. The TSS2 locus may be a negative regulator of abscisic acid signaling, because tss2 is hypersensitive to growth inhibition by abscisic acid. Our results demonstrate that the TSS1 locus is essential for K(+) nutrition and NaCl tolerance in tomato. Significantly, the isolation of the tss2 mutant demonstrates that abscisic acid signaling is also important for salt and osmotic tolerance in glycophytic plants. PMID:11283342

  6. 40 CFR 180.1285 - Polyoxin D zinc salt; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Polyoxin D zinc salt; exemption from... FOOD Exemptions From Tolerances § 180.1285 Polyoxin D zinc salt; exemption from the requirement of a... zinc salt in or on all food commodities when applied as a fungicide and used in accordance with...

  7. 40 CFR 180.1285 - Polyoxin D zinc salt; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Polyoxin D zinc salt; exemption from... FOOD Exemptions From Tolerances § 180.1285 Polyoxin D zinc salt; exemption from the requirement of a... zinc salt in or on all food commodities when applied as a fungicide and used in accordance with...

  8. DCA1 Acts as a Transcriptional Co-activator of DST and Contributes to Drought and Salt Tolerance in Rice.

    PubMed

    Cui, Long-Gang; Shan, Jun-Xiang; Shi, Min; Gao, Ji-Ping; Lin, Hong-Xuan

    2015-10-01

    Natural disasters, including drought and salt stress, seriously threaten food security. In previous work we cloned a key zinc finger transcription factor gene, Drought and Salt Tolerance (DST), a negative regulator of drought and salt tolerance that controls stomatal aperture in rice. However, the exact mechanism by which DST regulates the expression of target genes remains unknown. In the present study, we demonstrated that DST Co-activator 1 (DCA1), a previously unknown CHY zinc finger protein, acts as an interacting co-activator of DST. DST was found to physically interact with itself and to form a heterologous tetramer with DCA1. This transcriptional complex appears to regulate the expression of peroxidase 24 precursor (Prx 24), a gene encoding an H2O2 scavenger that is more highly expressed in guard cells. Downregulation of DCA1 significantly enhanced drought and salt tolerance in rice, and overexpression of DCA1 increased sensitivity to stress treatment. These phenotypes were mainly influenced by DCA1 and negatively regulated stomatal closure through the direct modulation of genes associated with H2O2 homeostasis. Our findings establish a framework for plant drought and salt stress tolerance through the DCA1-DST-Prx24 pathway. Moreover, due to the evolutionary and functional conservation of DCA1 and DST in plants, engineering of this pathway has the potential to improve tolerance to abiotic stress in other important crop species. PMID:26496194

  9. DCA1 Acts as a Transcriptional Co-activator of DST and Contributes to Drought and Salt Tolerance in Rice

    PubMed Central

    Cui, Long-Gang; Shan, Jun-Xiang; Shi, Min; Gao, Ji-Ping; Lin, Hong-Xuan

    2015-01-01

    Natural disasters, including drought and salt stress, seriously threaten food security. In previous work we cloned a key zinc finger transcription factor gene, Drought and Salt Tolerance (DST), a negative regulator of drought and salt tolerance that controls stomatal aperture in rice. However, the exact mechanism by which DST regulates the expression of target genes remains unknown. In the present study, we demonstrated that DST Co-activator 1 (DCA1), a previously unknown CHY zinc finger protein, acts as an interacting co-activator of DST. DST was found to physically interact with itself and to form a heterologous tetramer with DCA1. This transcriptional complex appears to regulate the expression of peroxidase 24 precursor (Prx 24), a gene encoding an H2O2 scavenger that is more highly expressed in guard cells. Downregulation of DCA1 significantly enhanced drought and salt tolerance in rice, and overexpression of DCA1 increased sensitivity to stress treatment. These phenotypes were mainly influenced by DCA1 and negatively regulated stomatal closure through the direct modulation of genes associated with H2O2 homeostasis. Our findings establish a framework for plant drought and salt stress tolerance through the DCA1-DST-Prx24 pathway. Moreover, due to the evolutionary and functional conservation of DCA1 and DST in plants, engineering of this pathway has the potential to improve tolerance to abiotic stress in other important crop species. PMID:26496194

  10. Function and expression of a novel rat salt-tolerant protein: evidence of a role in cellular sodium metabolism.

    PubMed

    Tsuji, E; Tsuji, Y; Sasaguri, M; Arakawa, K

    1998-09-01

    Higher dietary salt intake in humans is associated with higher BP, but the BP response to NaCl, so-called salt sensitivity, is heterogeneous among individuals. It has been postulated that modifications in cellular cation metabolism may be related to salt sensitivity in mammalian hypertension. The authors have isolated a novel rat complementary DNA, called salt-tolerant protein (STP), that can functionally complement Saccharomyces cervisiae HAL1, which improves salt tolerance by modulating the cation transport system. On high-salt (8% NaCl) diets, both Dahl salt-sensitive and salt-resistant rats displayed an elevated BP and increased STP mRNA expression. Immunohistochemistry using an anti-rat STP antibody demonstrated the presence of STP immunoreactivity in the proximal tubules. In cells that transiently expressed STP, the intracellular [Na+]/[K+] ratio was higher than that in control cells. STP contains predicted coiled-coil and Src homology 3 domains, and shows a partially high degree of nucleotide identity to human thyroid-hormone receptor interacting protein. These results suggest that STP may play an important role in salt sensitivity through cellular sodium metabolism by mediating signal transduction and a hormone-dependent transcription mechanism. PMID:9727364

  11. Salt-Induced Stabilization of EIN3/EIL1 Confers Salinity Tolerance by Deterring ROS Accumulation in Arabidopsis

    PubMed Central

    Wen, Xing; Li, Wenyang; Shi, Hui; Yang, Longshu; Zhu, Huaiqiu; Guo, Hongwei

    2014-01-01

    Ethylene has been regarded as a stress hormone to regulate myriad stress responses. Salinity stress is one of the most serious abiotic stresses limiting plant growth and development. But how ethylene signaling is involved in plant response to salt stress is poorly understood. Here we showed that Arabidopsis plants pretreated with ethylene exhibited enhanced tolerance to salt stress. Gain- and loss-of-function studies demonstrated that EIN3 (ETHYLENE INSENSITIVE 3) and EIL1 (EIN3-LIKE 1), two ethylene-activated transcription factors, are necessary and sufficient for the enhanced salt tolerance. High salinity induced the accumulation of EIN3/EIL1 proteins by promoting the proteasomal degradation of two EIN3/EIL1-targeting F-box proteins, EBF1 and EBF2, in an EIN2-independent manner. Whole-genome transcriptome analysis identified a list of SIED (Salt-Induced and EIN3/EIL1-Dependent) genes that participate in salt stress responses, including several genes encoding reactive oxygen species (ROS) scavengers. We performed a genetic screen for ein3 eil1-like salt-hypersensitive mutants and identified 5 EIN3 direct target genes including a previously unknown gene, SIED1 (At5g22270), which encodes a 93-amino acid polypeptide involved in ROS dismissal. We also found that activation of EIN3 increased peroxidase (POD) activity through the direct transcriptional regulation of PODs expression. Accordingly, ethylene pretreatment or EIN3 activation was able to preclude excess ROS accumulation and increased tolerance to salt stress. Taken together, our study provides new insights into the molecular action of ethylene signaling to enhance plant salt tolerance, and elucidates the transcriptional network of EIN3 in salt stress response. PMID:25330213

  12. Overexpression of the PtSOS2 gene improves tolerance to salt stress in transgenic poplar plants.

    PubMed

    Yang, Yang; Tang, Ren-Jie; Jiang, Chun-Mei; Li, Bei; Kang, Tao; Liu, Hua; Zhao, Nan; Ma, Xu-Jun; Yang, Lei; Chen, Shao-Liang; Zhang, Hong-Xia

    2015-09-01

    In higher plants, the salt overly sensitive (SOS) signalling pathway plays a crucial role in maintaining ion homoeostasis and conferring salt tolerance under salinity condition. Previously, we functionally characterized the conserved SOS pathway in the woody plant Populus trichocarpa. In this study, we demonstrate that overexpression of the constitutively active form of PtSOS2 (PtSOS2TD), one of the key components of this pathway, significantly increased salt tolerance in aspen hybrid clone Shanxin Yang (Populus davidiana × Populus bolleana). Compared to the wild-type control, transgenic plants constitutively expressing PtSOS2TD exhibited more vigorous growth and produced greater biomass in the presence of high concentrations of NaCl. The improved salt tolerance was associated with a decreased Na(+) accumulation in the leaves of transgenic plants. Further analyses revealed that plasma membrane Na(+) /H(+) exchange activity and Na(+) efflux in transgenic plants were significantly higher than those in the wild-type plants. Moreover, transgenic plants showed improved capacity in scavenging reactive oxygen species (ROS) generated by salt stress. Taken together, our results suggest that PtSOS2 could serve as an ideal target gene to genetically engineer salt-tolerant trees. PMID:25641517

  13. 40 CFR 180.129 - o-Phenylphenol and its sodium salt; tolerances for residues.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false o-Phenylphenol and its sodium salt; tolerances for residues. 180.129 Section 180.129 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.129 o-Phenylphenol...

  14. 40 CFR 180.129 - o-Phenylphenol and its sodium salt; tolerances for residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false o-Phenylphenol and its sodium salt; tolerances for residues. 180.129 Section 180.129 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.129 o-Phenylphenol...

  15. 40 CFR 180.129 - o-Phenylphenol and its sodium salt; tolerances for residues.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false o-Phenylphenol and its sodium salt; tolerances for residues. 180.129 Section 180.129 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.129 o-Phenylphenol...

  16. 40 CFR 180.129 - o-Phenylphenol and its sodium salt; tolerances for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false o-Phenylphenol and its sodium salt; tolerances for residues. 180.129 Section 180.129 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.129 o-Phenylphenol...

  17. Development of EST-SSR markers related to salt tolerance and their application in genetic diversity and evolution analysis in Gossypium.

    PubMed

    Wang, B H; Zhu, P; Yuan, Y L; Wang, C B; Yu, C M; Zhang, H H; Zhu, X Y; Wang, W; Yao, C B; Zhuang, Z M; Li, P

    2014-01-01

    Salt stress is becoming one of the major problems in global agriculture with the onset of global warming, an increasing scarcity of fresh water, and improper land irrigation and fertilization practices, which leads to reduction of crop output and even causes crop death. To speed up the exploitation of saline land, it is a good choice to grow plants with a high level of salt tolerance and economic benefits. As the leading fiber crop grown commercially worldwide, cotton is placed in the moderately salt-tolerant group of plant species, and there is promising potential to improve salt tolerance in cultivated cotton. To facilitate the mapping of salt-tolerant quantitative trait loci in cotton so as to serve the aims of salt-tolerant molecular breeding in cotton, it is necessary to develop salt-tolerant molecular markers. The objective of this research was to develop simple sequence repeat (SSR) markers based on cotton salt-tolerant expressed sequence tags. To test the efficacy of these SSR markers, their polymorphism and cross-species transferability were evaluated, and their value was further investigated on the basis of genetic diversity and evolution analysis. PMID:24854659

  18. Nuclear-localized AtHSPR links abscisic acid-dependent salt tolerance and antioxidant defense in Arabidopsis.

    PubMed

    Yang, Tao; Zhang, Liang; Hao, Hongyan; Zhang, Peng; Zhu, Haowei; Cheng, Wei; Wang, Yongli; Wang, Xinyu; Wang, Chongying

    2015-12-01

    Salt stress from soil or irrigation water limits plant growth. A T-DNA insertion mutant in C24, named athspr (Arabidopsis thaliana heat shock protein-related), showed several phenotypes, including reduced organ size and enhanced sensitivity to environmental cues. The athspr mutant is severely impaired under salinity levels at which wild-type (WT) plants grow normally. AtHSPR encodes a nuclear-localized protein with ATPase activity, and its expression was enhanced by high salinity and abscisic acid (ABA). Overexpression (OE) of AtHSPR significantly enhanced tolerance to salt stress by increasing the activities of the antioxidant system and by maintaining K(+) /Na(+) homeostasis. Quantitative RT-PCR analyses showed that OE of AtHSPR increased the expression of ABA/stress-responsive, salt overly sensitive (SOS)-related and antioxidant-related genes. In addition, ABA content was reduced in athspr plants with or without salt stress, and exogenous ABA restored WT-like salt tolerance to athspr plants. athspr exhibited increased leaf stomatal density and stomatal index, slower ABA-induced stomatal closure and reduced drought tolerance relative to the WT. AtHSPR OE enhanced drought tolerance by reducing leaf water loss and stomatal aperture. Transcript profiling in athspr showed a differential salt-stress response for genes involved in accumulation of reactive oxygen species (ROS), ABA signaling, cell death, stress response and photosynthesis. Taken together, our results suggested that AtHSPR is involved in salt tolerance in Arabidopsis through modulation of ROS levels, ABA-dependent stomatal closure, photosynthesis and K(+) /Na(+) homeostasis. PMID:26603028

  19. Physiological Evaluation of Alkali-Salt Tolerance of Thirty Switchgrass (Panicum virgatum) Lines.

    PubMed

    Hu, Guofu; Liu, Yiming; Zhang, Xunzhong; Yao, Fengjiao; Huang, Yan; Ervin, Erik H; Zhao, Bingyu

    2015-01-01

    Soil salt-alkalization is a major limiting factor for crop production in many regions. Switchgrass (Panicum virgatum L.) is a warm-season C4 perennial rhizomatous bunchgrass and a target lignocellulosic biofuel species. The objective of this study was to evaluate relative alkali-salt tolerance among 30 switchgrass lines. Tillers of each switchgrass line were transplanted into pots filled with fine sand. Two months after transplanting, plants at E5 developmental stage were grown in either half strength Hoagland's nutrient solution with 0 mM Na+ (control) or half strength Hoagland's nutrient solution with 150 mM Na+ and pH of 9.5 (alkali-salt stress treatment) for 20 d. Alkali-salt stress damaged cell membranes [higher electrolyte leakage (EL)], reduced leaf relative water content (RWC), net photosynthetic rate (Pn), stomatal conductance (gs), and transpiration rate (Tr). An alkali-salt stress tolerance trait index (ASTTI) for each parameter was calculated based on the ratio of the value under alkali-salt stress and the value under non-stress conditions for each parameter of each line. Relative alkali-salt tolerance was determined based on principal components analysis and cluster analysis of the physiological parameters and their ASTTI values. Significant differences in alkali-salt stress tolerance were found among the 30 lines. Lowland lines TEM-SEC, Alamo, TEM-SLC and Kanlow were classified as alkali-salt tolerant. In contrast, three lowland lines (AM-314/MS-155, BN-13645-64) and two upland lines (Caddo and Blackwell-1) were classified as alkali-salt sensitive. The results suggest wide variations exist in alkali-salt stress tolerance among the 30 switchgrass lines. The approach of using a combination of principal components and cluster analysis of the physiological parameters and related ASTTI is feasible for evaluating alkali-salt tolerance in switchgrass. PMID:26146987

  20. The RING Finger E3 Ligase SpRing is a Positive Regulator of Salt Stress Signaling in Salt-Tolerant Wild Tomato Species.

    PubMed

    Qi, Shilian; Lin, Qingfang; Zhu, Huishan; Gao, Fenghua; Zhang, Wenhao; Hua, Xuejun

    2016-03-01

    Protein ubiquitination in plants plays critical roles in many biological processes, including adaptation to abiotic stresses. Previously, RING finger E3 ligase has been characterized during salt stress response in several plant species, but little is known about its function in tomato. Here, we report that SpRing, a stress-inducible gene, is involved in salt stress signaling in wild tomato species Solanum pimpinellifolium 'PI365967'. In vitro ubiquitination assay revealed that SpRing is an E3 ubiquitin ligase and the RING finger conserved region is required for its activity. SpRing is expressed in all tissues of wild tomato and up-regulated by salt, drought and osmotic stresses, but repressed by low temperature. Green fluorescent protein (GFP) fusion analysis showed that SpRing is localized at the endoplasmic reticulum. Silencing of SpRing through a virus-induced gene silencing approach led to increased sensitivity to salt stress in wild tomato. Overexpression of SpRing in Arabidopsis thaliana resulted in enhanced salt tolerance during seed germination and early seedling development. The expression levels of certain key stress-related genes are altered both in SpRing-overexpressing Arabidopsis plants and virus-induced gene silenced tomato seedlings. Taken together, our results indicate that SpRing is involved in salt stress and functions as a positive regulator of salt tolerance. PMID:26786853

  1. Symbiosis increases coral tolerance to ocean acidification

    NASA Astrophysics Data System (ADS)

    Ohki, S.; Irie, T.; Inoue, M.; Shinmen, K.; Kawahata, H.; Nakamura, T.; Kato, A.; Nojiri, Y.; Suzuki, A.; Sakai, K.; van Woesik, R.

    2013-04-01

    Increasing the acidity of ocean waters will directly threaten calcifying marine organisms such as reef-building scleractinian corals, and the myriad of species that rely on corals for protection and sustenance. Ocean pH has already decreased by around 0.1 pH units since the beginning of the industrial revolution, and is expected to decrease by another 0.2-0.4 pH units by 2100. This study mimicked the pre-industrial, present, and near-future levels of pCO2 using a precise control system (±5% pCO2), to assess the impact of ocean acidification on the calcification of recently-settled primary polyps of Acropora digitifera, both with and without symbionts, and adult fragments with symbionts. The increase in pCO2 of 100 μatm between the pre-industrial period and the present had more effect on the calcification rate of adult A. digitifera than the anticipated future increases of several hundreds of micro-atmospheres of pCO2. The primary polyps with symbionts showed higher calcification rates than primary polyps without symbionts, suggesting that (i) primary polyps housing symbionts are more tolerant to near-future ocean acidification than organisms without symbionts, and (ii) corals acquiring symbionts from the environment (i.e. broadcasting species) will be more vulnerable to ocean acidification than corals that maternally acquire symbionts.

  2. Salt intrusion in tidal wetlands: European willow species tolerate oligohaline conditions

    NASA Astrophysics Data System (ADS)

    Markus-Michalczyk, Heike; Hanelt, Dieter; Ludewig, Kristin; Müller, David; Schröter, Brigitte; Jensen, Kai

    2014-01-01

    Tidal wetlands experience salt intrusion due to the effects of climate change. This study clarifies that the European flood plain willows species Salix alba and Salix viminalis tolerate oligohaline conditions. Salix alba L. and Salix viminalis L. are distributed on flood plains up to transitional waters of the oligohaline to the mesohaline estuarine stretch in temperate climates. They experience spatial and temporal variations in flooding and salinity. In the past, willows dominated the vegetation above the mean high water line, attenuated waves and contributed to sedimentation. In recent centuries, human utilization reduced willow stands. Today, the Elbe estuary - a model system for an estuary in temperate zones - exhibits increasing flooding and salinity due to man-induced effects and climatic changes. Willows were described as having no salinity tolerance. In contrast, our soil water salinity measurements at willows in tidal wetlands prove that mature Salix individuals tolerate oligohaline conditions. To assess immature plant salinity tolerance, we conducted a hydroponic greenhouse experiment. Vegetative propagules originating from a freshwater and an oligohaline site were treated in four salinities. Related to growth rates and biomass production, we found interspecific similarities and a salinity tolerance up to salinity 2. Vitality and chlorophyll fluorescence indicated an acclimation of Salix viminalis to oligohaline conditions. We conclude, that the survival of S. alba and S. viminalis and the restoration of willow stands in estuarine flood plains - with regard to wave attenuation and sedimentation - might be possible, despite increasing salinity in times of climate change.

  3. Over-expression of poplar transcription factor ERF76 gene confers salt tolerance in transgenic tobacco.

    PubMed

    Yao, Wenjing; Wang, Lei; Zhou, Boru; Wang, Shengji; Li, Renhua; Jiang, Tingbo

    2016-07-01

    Ethylene response factors (ERFs) belong to a large plant-specific transcription factor family, which play a significant role in plant development and stress responses. Poplar ERF76 gene, a member of ERF TF family, can be up-regulated in response to salt stress, osmotic stress, and ABA treatment. The ERF76 protein was confirmed to be targeted preferentially in the nucleus of onion cell by particle bombardment. In order to understand the functions of ERF76 gene in salt stress response, we conducted temporal and spatial expression analysis of ERF76 gene in poplar. Then the ERF76 cDNA fragment containing an ORF was cloned from di-haploid Populus simonii×P. nigra and transferred into tobacco (Nicotiana tobacum) genome by Agrobacterium-mediated leaf disc method. Under salt stress, transgenic tobacco over-expressing ERF76 gene showed a significant increase in seed germination rate, plant height, root length, and fresh weight, as well as in relative water content (RWC), superoxide dismutase (SOD) activity, peroxidase (POD) activity, and proline content, compared to control tobacco lines. In contrast, transgenic tobacco lines displayed a decrease in malondialdehyde (MDA) accumulation, relative electrical conductivity (REC) and reactive oxygen species (ROS) accumulation in response to salt stress, compared to control tobacco lines. Over all, the results indicated that ERF76 gene plays a critical role in salt tolerance in transgenic tobacco. PMID:27123829

  4. Transcriptome analysis reveals that distinct metabolic pathways operate in salt-tolerant and salt-sensitive upland cotton varieties subjected to salinity stress.

    PubMed

    Guo, Jinyan; Shi, Gongyao; Guo, Xiaoyan; Zhang, Liwei; Xu, Wenying; Wang, Yumei; Su, Zhen; Hua, Jinping

    2015-09-01

    Salinity stress is one of the most devastating abiotic stresses in crop plants. As a moderately salt-tolerant crop, upland cotton (Gossypium hirsutum L.) is a major cash crop in saline areas and a suitable model for salt stress tolerance research. In this study, we compared the transcriptome changes between the salt-tolerant upland cotton cultivar Zhong 07 and salt-sensitive cultivar Zhong G5 in response to NaCl treatments. Transcriptional regulation, signal transduction and secondary metabolism in two varieties showed significant differences, all of which might be related to mechanisms underlying salt stress tolerance. The transcriptional profiles presented here provide a foundation for deciphering the mechanism underlying salt tolerance. Based on our findings, we proposed several candidate genes that might be used to improve salt tolerance in upland cotton. PMID:26259172

  5. EHD1 functions in endosomal recycling and confers salt tolerance.

    PubMed

    Bar, Maya; Leibman, Meirav; Schuster, Silvia; Pitzhadza, Hilla; Avni, Adi

    2013-01-01

    Endocytosis is a crucial process in all eukaryotic organisms including plants. We have previously shown that two Arabidopsis proteins, AtEHD1 and AtEHD2, are involved in endocytosis in plant systems. Knock-down of EHD1 was shown to have a delayed recycling phenotype in mammalians. There are many works in mammalian systems detailing the importance of the various domains in EHDs but, to date, the domains of plant EHD1 that are required for its activity have not been characterized. In this work we demonstrate that knock-down of EHD1 causes a delayed recycling phenotype and reduces Brefeldin A sensitivity in Arabidopsis seedlings. The EH domain of EHD1 was found to be crucial for the localization of EHD1 to endosomal structures. Mutant EHD1 lacking the EH domain did not localize to endosomal structures and showed a phenotype similar to that of EHD1 knock-down seedlings. Mutants lacking the coiled-coil domain, however, showed a phenotype similar to wild-type or EHD1 overexpression seedlings. Salinity stress is a major problem in current agriculture. Microarray data demonstrated that salinity stress enhances the expression of EHD1, and this was confirmed by semi quantitative RT-PCR. We demonstrate herein that transgenic plants over expressing EHD1 possess enhanced tolerance to salt stress, a property which also requires an intact EH domain. PMID:23342166

  6. Soil bacteria confer plant salt tolerance by tissue-specific regulation of the sodium transporter HKT1

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Elevated sodium (Na+) decreases plant growth and thereby agricultural productivity. The ion transporter HKT1 controls Na+ import in roots, yet dysfunction or over-expression of HKT1 fails to increase salt tolerance, raising questions as to HKT1’s role in regulating Na+ homeostasis. Here, we report t...

  7. Salt tolerance is related to a specific antioxidant response in the halophyte cordgrass, Spartina densiflora

    NASA Astrophysics Data System (ADS)

    Canalejo, Antonio; Martínez-Domínguez, David; Córdoba, Francisco; Torronteras, Rafael

    2014-06-01

    Halophytes usually have a robust antioxidative defense system to alleviate oxidative damage during salt stress. Spartina densiflora is a colonizing halophyte cordgrass, native of South America, which has become a common species in salt marshes of northern hemisphere, where it is ousting indigenous species. This study addressed salinity stress in S. densiflora; the occurrence of oxidative stress and the possible involvement of the antioxidative system in its high salt tolerance were studied. Plants were evaluated at in situ conditions, in the laboratory during a 28 day-acclimation period (AP) in clean substrate irrigated with a control salt content of 4 g L-1 (68 mM) and during a subsequent 28 day-treatment period (TP) exposed to different NaCl concentrations: control (68 mM), 428 mM or 680 mM. In the in situ setting, the high leave Na+ content was accompanied by high levels of hydroperoxides and reduced levels of total chlorophyll and carotenes, which correlated with enhanced activation of antioxidant defense biomarkers as total ascorbic acid (AA) content and guaiacol peroxidase (POD: EC 1.11.1.7)), catalase (CAT: EC 1.11.1.6) and ascorbate peroxidase (APX: EC 1.11.1.11) activities. Throughout the AP, leave Na+ and oxidative stress markers decreased concomitantly and reached stable low levels. During the TP, dose and time-dependent accumulation of Na+ in high NaCl-treated plants was concurrent with a decrease in content of total chlorophyll and carotenes and with an increase in the levels of total AA and CAT and APX activities. In conclusion, as hypothesized, high salinity induces conditions of oxidative stress in S. densiflora, so that its salt tolerance appears to be related to the implementation of a specific antioxidant response. This may account for Spartina densiflora's successful adaptation to habitats with fluctuating salinity and favour its phytoremediation potential.

  8. Site Suitability Analysis for Dissemination of Salt-tolerant Rice Varieties in Southern Bangladesh

    NASA Astrophysics Data System (ADS)

    Sinha, D. D.; Singh, A. N.; Singh, U. S.

    2014-11-01

    Bangladesh is a country of 14.4 million ha geographical area and has a population density of more than 1100 persons per sq. km. Rice is the staple food crop, growing on about 72 % of the total cultivated land and continues to be the most important crop for food security of the country. A project "Sustainable Rice Seed Production and Delivery Systems for Southern Bangladesh" has been executed by the International Rice Research Institute (IRRI) in twenty southern districts of Bangladesh. These districts grow rice in about 2.9 million ha out of the country's total rice area of 11.3 million ha. The project aims at contributing to the Government of Bangladesh's efforts in improving national and household food security through enhanced and sustained productivity by using salinity-, submergence- and drought- tolerant and high yielding rice varieties. Out of the 20 project districts, 12 coastal districts are affected by the problem of soil salinity. The salt-affected area in Bangladesh has increased from about 0.83 million ha in 1973 to 1.02 million ha in 2000, and 1.05 million ha in 2009 due to the influence of cyclonic storms like "Sidr", "Laila" and others, leading to salt water intrusion in croplands. Three salinity-tolerant rice varieties have recently been bred by IRRI and field tested and released by the Bangladesh Rice Research Institute (BRRI) and Bangladesh Institute of Nuclear Agriculture (BINA). These varieties are BRRI dhan- 47 and Bina dhan-8 and - 10. However, they can tolerate soil salinity level up to EC 8-10 dSm-1, whereas the EC of soils in several areas are much higher. Therefore, a large scale dissemination of these varieties can be done only when a site suitability analysis of the area is carried out. The present study was taken up with the objective of preparing the site suitability of the salt-tolerant varieties for the salinity-affected districts of southern Bangladesh. Soil salinity map prepared by Soil Resources Development Institute of

  9. Genetic analysis of salt-tolerant mutants in Arabidopsis thaliana.

    PubMed Central

    Quesada, V; Ponce, M R; Micol, J L

    2000-01-01

    Stress caused by the increased salinity of irrigated fields impairs plant growth and is one of the major constraints that limits crop productivity in many important agricultural areas. As a contribution to solving such agronomic problems, we have carried out a large-scale screening for Arabidopsis thaliana mutants induced on different genetic backgrounds by EMS treatment, fast neutron bombardment, or T-DNA insertions. From the 675,500 seeds we screened, 17 mutant lines were isolated, all but one of which yielded 25-70% germination levels on 250 mm NaCl medium, a condition in which their ancestor ecotypes are unable to germinate. Monogenic recessive inheritance of NaCl-tolerant germination was displayed with incomplete penetrance by all the selected mutants, which fell into five complementation groups. These were named SALOBRENO (SAN) and mapped relative to polymorphic microsatellites, the map positions of three of them suggesting that they are novel genes. Strains carrying mutations in the SAN1-SAN4 genes display similar responses to both ionic effects and osmotic pressure, their germination being NaCl and mannitol tolerant but KCl and Na(2)SO(4) sensitive. In addition, NaCl-, KCl-, and mannitol-tolerant as well as abscisic-acid-insensitive germination was displayed by sañ5, whose genetic and molecular characterization indicates that it carries an extremely hypomorphic or null allele of the ABI4 gene, its deduced protein product lacking the APETALA2 DNA binding domain. PMID:10629000

  10. Enhanced tolerance to salt stress in transgenic rice that overexpresses chloroplast glutamine synthetase.

    PubMed

    Hoshida, H; Tanaka, Y; Hibino, T; Hayashi, Y; Tanaka, A; Takabe, T; Takabe, T

    2000-05-01

    The potential role of photorespiration in the protection against salt stress was examined with transgenic rice plants. Oryza sativa L. cv. Kinuhikari was transformed with a chloroplastic glutamine synthetase (GS2) gene from rice. Each transgenic rice plant line showed a different accumulation level of GS2. A transgenic plant line, G39-2, which accumulated about 1.5-fold more GS2 than the control plant, had an increased photorespiration capacity. In another line, G241-12, GS2 was almost lost and photorespiration activity could not be detected. Fluorescence quenching analysis revealed that photorespiration could prevent the over-reduction of electron transport systems. When exposed to 150 mM NaCl for 2 weeks, the control rice plants completely lost photosystem II activity, but G39-2 plants retained more than 90% activity after the 2-week treatment, whereas G241-12 plants lost these activities within one week. In the presence of isonicotinic acid hydrazide, an inhibitor of photorespiration, G39-2 showed the same salt tolerance as the control plants. The intracellular contents of NH4+ and Na+ in the stressed plants correlated well with the levels of GS2. Thus, the enhancement of photorespiration conferred resistance to salt in rice plants. Preliminary results suggest chilling tolerance in the transformant. PMID:10949377

  11. Changes in hydraulic conductance cause the difference in growth response to short-term salt stress between salt-tolerant and -sensitive black gram (Vigna mungo) varieties.

    PubMed

    Win, Khin Thuzar; Oo, Aung Zaw; Ookawa, Taiichiro; Kanekatsu, Motoki; Hirasawa, Tadashii

    2016-04-01

    Black gram (Vigna mungo) is an important crop in Asia, However, most black gram varieties are salt-sensitive. The causes of varietal differences in salt-induced growth reduction between two black gram varieties, 'U-Taung-2' (salt-tolerant; BT) and 'Mut Pe Khaing To' (salt-sensitive; BS), were examined the potential for the first step toward the genetic improvement of salt tolerance. Seedlings grown in vermiculite irrigated with full-strength Hoagland solution were treated with 0mM NaCl (control) or 225mM NaCl for up to 10 days. In the 225mM NaCl treatment, plant growth rate, net assimilation rate, mean leaf area, leaf water potential, and leaf photosynthesis were reduced more in BS than in BT plants. Leaf water potential was closely related to leaf photosynthesis, net assimilation rate, and increase in leaf area. In response to salinity stress, hydraulic conductance of the root, stem, and petiole decreased more strongly in BS than in BT plants. The reduction in stem and petiole hydraulic conductance was caused by cavitation, whereas the reduction in root hydraulic conductance in BS plants was caused by a reduction in root surface area and hydraulic conductivity. We conclude that the different reduction in hydraulic conductance is a cause of the differences in the growth response between the two black gram varieties under short-term salt stress. PMID:26962708

  12. Arabidopsis AINTEGUMENTA mediates salt tolerance by trans-repressing SCABP8.

    PubMed

    Meng, Lai-Sheng; Wang, Yi-Bo; Yao, Shun-Qiao; Liu, Aizhong

    2015-08-01

    The Arabidopsis AINTEGUMENTA (ANT) gene, which encodes an APETALA2 (AP2)-like transcription factor, controls plant organ cell number and organ size throughout shoot development. ANT is thus a key factor in the development of plant shoots. Here, we have found that ANT plays an essential role in conferring salt tolerance in Arabidopsis. ant-knockout mutants presented a salt-tolerant phenotype, whereas transgenic plants expressing ANT under the 35S promoter (35S:ANT) exhibited more sensitive phenotypes under high salt stress. Further analysis indicated that ANT functions mainly in the shoot response to salt toxicity. Target gene analysis revealed that ANT bound to the promoter of SOS3-LIKE CALCIUM BINDING PROTEIN 8 (SCABP8), which encodes a putative Ca(2+) sensor, thereby inhibiting expression of SCABP8 (also known as CBL10). It has been reported that the salt sensitivity of scabp8 is more prominent in shoot tissues. Genetic experiments indicated that the mutation of SCABP8 suppresses the ant-knockout salt-tolerant phenotype, implying that ANT functions as a negative transcriptional regulator of SCABP8 upon salt stress. Taken together, the above results reveal that ANT is a novel regulator of salt stress and that ANT binds to the SCABP8 promoter, mediating salt tolerance. PMID:26054800

  13. Burkholderia phytofirmans PsJN induces long-term metabolic and transcriptional changes involved in Arabidopsis thaliana salt tolerance.

    PubMed

    Pinedo, Ignacio; Ledger, Thomas; Greve, Macarena; Poupin, María J

    2015-01-01

    Salinity is one of the major limitations for food production worldwide. Improvement of plant salt-stress tolerance using plant-growth promoting rhizobacteria (PGPR) has arisen as a promising strategy to help overcome this limitation. However, the molecular and biochemical mechanisms controlling PGPR/plant interactions under salt-stress remain unclear. The main objective of this study was to obtain new insights into the mechanisms underlying salt-stress tolerance enhancement in the salt-sensitive Arabidopsis thaliana Col-0 plants, when inoculated with the well-known PGPR strain Burkholderia phytofirmans PsJN. To tackle this, different life history traits, together with the spatiotemporal accumulation patterns for key metabolites and salt-stress related transcripts, were analyzed in inoculated plants under short and long-term salt-stress. Inoculated plants displayed faster recovery and increased tolerance after sustained salt-stress. PsJN treatment accelerated the accumulation of proline and transcription of genes related to abscisic acid signaling (Relative to Dessication, RD29A and RD29B), ROS scavenging (Ascorbate Peroxidase 2), and detoxification (Glyoxalase I 7), and down-regulated the expression of Lipoxygenase 2 (related to jasmonic acid biosynthesis). Among the general transcriptional effects of this bacterium, the expression pattern of important ion-homeostasis related genes was altered after short and long-term stress (Arabidopsis K(+) Transporter 1, High-Affinity K(+) Transporter 1, Sodium Hydrogen Exchanger 2, and Arabidopsis Salt Overly Sensitive 1). In all, the faster and stronger molecular changes induced by the inoculation suggest a PsJN-priming effect, which may explain the observed tolerance after short-term and sustained salt-stress in plants. This study provides novel information about possible mechanisms involved in salt-stress tolerance induced by PGPR in plants, showing that certain changes are maintained over time. This opens up new venues to

  14. Burkholderia phytofirmans PsJN induces long-term metabolic and transcriptional changes involved in Arabidopsis thaliana salt tolerance

    PubMed Central

    Pinedo, Ignacio; Ledger, Thomas; Greve, Macarena; Poupin, María J.

    2015-01-01

    Salinity is one of the major limitations for food production worldwide. Improvement of plant salt-stress tolerance using plant-growth promoting rhizobacteria (PGPR) has arisen as a promising strategy to help overcome this limitation. However, the molecular and biochemical mechanisms controlling PGPR/plant interactions under salt-stress remain unclear. The main objective of this study was to obtain new insights into the mechanisms underlying salt-stress tolerance enhancement in the salt-sensitive Arabidopsis thaliana Col-0 plants, when inoculated with the well-known PGPR strain Burkholderia phytofirmans PsJN. To tackle this, different life history traits, together with the spatiotemporal accumulation patterns for key metabolites and salt-stress related transcripts, were analyzed in inoculated plants under short and long-term salt-stress. Inoculated plants displayed faster recovery and increased tolerance after sustained salt-stress. PsJN treatment accelerated the accumulation of proline and transcription of genes related to abscisic acid signaling (Relative to Dessication, RD29A and RD29B), ROS scavenging (Ascorbate Peroxidase 2), and detoxification (Glyoxalase I 7), and down-regulated the expression of Lipoxygenase 2 (related to jasmonic acid biosynthesis). Among the general transcriptional effects of this bacterium, the expression pattern of important ion-homeostasis related genes was altered after short and long-term stress (Arabidopsis K+ Transporter 1, High-Affinity K+ Transporter 1, Sodium Hydrogen Exchanger 2, and Arabidopsis Salt Overly Sensitive 1). In all, the faster and stronger molecular changes induced by the inoculation suggest a PsJN-priming effect, which may explain the observed tolerance after short-term and sustained salt-stress in plants. This study provides novel information about possible mechanisms involved in salt-stress tolerance induced by PGPR in plants, showing that certain changes are maintained over time. This opens up new venues to

  15. Modifying K sup + /Na sup + discrimination in salt-stressed wheat containing individual chromosomes of a salt-tolerant lophopyrum

    SciTech Connect

    Epstein, E.; Dvorak, J.

    1990-01-01

    As outlined in the proposal for this project, the practical or applied impetus for this research is this: salinity of soils and water is inimical to the production of crops and other plants biomass, and to that extent causes a dimunition of the world's capture of solar energy. Of the two strategies of coping with this problem -- rendering soils and water less saline, and developing plants better able to cope with saline substrates -- the present project deals with the latter. The current prolonged drought in California and elsewhere in the West prompts an energetic pursuit of this option, for the availability of less water is tantamount to a general exacerbation of the salinity threat. Bread wheat, Triticum aestivum, is relatively salt-sensitive, whereas tall wheatgrass, Lophopyrum elongatum, is highly salt-tolerant, as shown in our laboratory in investigations going back to the 1960's. In the present investigation both the degree of salt tolerance and that of K{sup +}/Na{sup +} discrimination have been examined in wheat, Triticum aestivum, Chinese Spring,' the wheat x L. elongatum amphiploid, and a set of 20 disomic substitution lines. The latter would reveal which of the L. elongatum chromosomes substituted for their homoeologues in wheat contribute salt tolerance to wheat, and what congruence, if any, exists between that degree of salt tolerance and changes in K{sup +}/Na{sup +} discrimination in the target wheat.

  16. An RNA chaperone, AtCSP2, negatively regulates salt stress tolerance

    PubMed Central

    Sasaki, Kentaro; Liu, Yuelin; Kim, Myung-Hee; Imai, Ryozo

    2015-01-01

    Cold shock domain (CSD) proteins are RNA chaperones that destabilize RNA secondary structures. Arabidopsis Cold Shock Domain Protein 2 (AtCSP2), one of the 4 CSD proteins (AtCSP1-AtCSP4) in Arabidopsis, is induced during cold acclimation but negatively regulates freezing tolerance. Here, we analyzed the function of AtCSP2 in salt stress tolerance. A double mutant, with reduced AtCSP2 and no AtCSP4 expression (atcsp2–3 atcsp4–1), displayed higher survival rates after salt stress. In addition, overexpression of AtCSP2 resulted in reduced salt stress tolerance. These data demonstrate that AtCSP2 acts as a negative regulator of salt stress tolerance in Arabidopsis. PMID:26252779

  17. A salt-regulated peptide derived from the CAP superfamily protein negatively regulates salt-stress tolerance in Arabidopsis

    PubMed Central

    Chien, Pei-Shan; Nam, Hong Gil; Chen, Yet-Ran

    2015-01-01

    High salinity has negative impacts on plant growth through altered water uptake and ion-specific toxicities. Plants have therefore evolved an intricate regulatory network in which plant hormones play significant roles in modulating physiological responses to salinity. However, current understanding of the plant peptides involved in this regulatory network remains limited. Here, we identified a salt-regulated peptide in Arabidopsis. The peptide was 11 aa and was derived from the C terminus of a cysteine-rich secretory proteins, antigen 5, and pathogenesis-related 1 proteins (CAP) superfamily. This peptide was found by searching homologues in Arabidopsis using the precursor of a tomato CAP-derived peptide (CAPE) that was initially identified as an immune signal. In searching for a CAPE involved in salt responses, we screened CAPE precursor genes that showed salt-responsive expression and found that the PROAtCAPE1 (AT4G33730) gene was regulated by salinity. We confirmed the endogenous Arabidopsis CAP-derived peptide 1 (AtCAPE1) by mass spectrometry and found that a key amino acid residue in PROAtCAPE1 is critical for AtCAPE1 production. Moreover, although PROAtCAPE1 was expressed mainly in the roots, AtCAPE1 was discovered to be upregulated systemically upon salt treatment. The salt-induced AtCAPE1 negatively regulated salt tolerance by suppressing several salt-tolerance genes functioning in the production of osmolytes, detoxification, stomatal closure control, and cell membrane protection. This discovery demonstrates that AtCAPE1, a homologue of tomato immune regulator CAPE1, plays an important role in the regulation of salt stress responses. Our discovery thus suggests that the peptide may function in a trade-off between pathogen defence and salt tolerance. PMID:26093145

  18. Overexpression of Late Embryogenesis Abundant 14 enhances Arabidopsis salt stress tolerance.

    PubMed

    Jia, Fengjuan; Qi, Shengdong; Li, Hui; Liu, Pu; Li, Pengcheng; Wu, Changai; Zheng, Chengchao; Huang, Jinguang

    2014-11-28

    Late embryogenesis abundant (LEA) proteins are implicated in various abiotic stresses in higher plants. In this study, we identified a LEA protein from Arabidopsis thaliana, AtLEA14, which was ubiquitously expressed in different tissues and remarkably induced with increased duration of salt treatment. Subcellular distribution analysis demonstrated that AtLEA14 was mainly localized in the cytoplasm. Transgenic Arabidopsis and yeast overexpressing AtLEA14 all exhibited enhanced tolerance to high salinity. The transcripts of salt stress-responsive marker genes (COR15a, KIN1, RD29B and ERD10) were overactivated in AtLEA14 overexpressing lines compared with those in wild type plants under normal or salt stress conditions. In vivo and in vitro analysis showed that AtLEA14 could effectively stabilize AtPP2-B11, an important E3 ligase. These results suggested that AtLEA14 had important protective functions under salt stress conditions in Arabidopsis. PMID:25450686

  19. A banana aquaporin gene, MaPIP1;1, is involved in tolerance to drought and salt stresses

    PubMed Central

    2014-01-01

    Background Aquaporin (AQP) proteins function in transporting water and other small molecules through the biological membranes, which is crucial for plants to survive in drought or salt stress conditions. However, the precise role of AQPs in drought and salt stresses is not completely understood in plants. Results In this study, we have identified a PIP1 subfamily AQP (MaPIP1;1) gene from banana and characterized it by overexpression in transgenic Arabidopsis plants. Transient expression of MaPIP1;1-GFP fusion protein indicated its localization at plasma membrane. The expression of MaPIP1;1 was induced by NaCl and water deficient treatment. Overexpression of MaPIP1;1 in Arabidopsis resulted in an increased primary root elongation, root hair numbers and survival rates compared to WT under salt or drought conditions. Physiological indices demonstrated that the increased salt tolerance conferred by MaPIP1;1 is related to reduced membrane injury and high cytosolic K+/Na+ ratio. Additionally, the improved drought tolerance conferred by MaPIP1;1 is associated with decreased membrane injury and improved osmotic adjustment. Finally, reduced expression of ABA-responsive genes in MaPIP1;1-overexpressing plants reflects their improved physiological status. Conclusions Our results demonstrated that heterologous expression of banana MaPIP1;1 in Arabidopsis confers salt and drought stress tolerances by reducing membrane injury, improving ion distribution and maintaining osmotic balance. PMID:24606771

  20. Silicon enhanced salt tolerance by improving the root water uptake and decreasing the ion toxicity in cucumber

    PubMed Central

    Wang, Shiwen; Liu, Peng; Chen, Daoqian; Yin, Lina; Li, Hongbing; Deng, Xiping

    2015-01-01

    Although the effects of silicon application on enhancing plant salt tolerance have been widely investigated, the underlying mechanism has remained unclear. In this study, seedlings of cucumber, a medium silicon accumulator plant, grown in 0.83 mM silicon solution for 2 weeks were exposed to 65 mM NaCl solution for another 1 week. The dry weight and shoot/root ratio were reduced by salt stress, but silicon application significantly alleviated these decreases. The chlorophyll concentration, net photosynthetic rate, transpiration rate and leaf water content were higher in plants treated with silicon than in untreated plants under salt stress conditions. Further investigation showed that salt stress decreased root hydraulic conductance (Lp), but that silicon application moderated this salt-induced decrease in Lp. The higher Lp in silicon-treated plants may account for the superior plant water balance. Moreover, silicon application significantly decreased Na+ concentration in the leaves while increasing K+ concentration. Simultaneously, both free and conjugated types of polyamines were maintained at high levels in silicon-treated plants, suggesting that polyamines may be involved in the ion toxicity. Our results indicate that silicon enhances the salt tolerance of cucumber through improving plant water balance by increasing the Lp and reducing Na+ content by increasing polyamine accumulation. PMID:26442072

  1. Overexpression of quinone reductase from Salix matsudana Koidz enhances salt tolerance in transgenic Arabidopsis thaliana.

    PubMed

    Song, Xixi; Fang, Jie; Han, Xiaojiao; He, Xuelian; Liu, Mingying; Hu, Jianjun; Zhuo, Renying

    2016-01-15

    Quinone reductase (QR) is an oxidative-related gene and few studies have focused on its roles concerning salt stress tolerance in plants. In this study, we cloned and analyzed the QR gene from Salix matsudana, a willow with tolerance of moderate salinity. The 612-bp cDNA corresponding to SmQR encodes 203 amino acids. Expression of SmQR in Escherichia coli cells enhanced their tolerance under salt stress. In addition, transgenic Arabidopsis thaliana lines overexpressing SmQR exhibited higher salt tolerance as compared with WT, with higher QR activity and antioxidant enzyme activity as well as higher chlorophyll content, lower methane dicarboxylic aldehyde (MDA) content and electric conductivity under salt stress. Nitro blue tetrazolium (NBT) and 3,3'-diaminobenzidine (DAB) staining also indicated that the transgenic plants accumulated less reactive oxygen species compared to WT when exposed to salt stress. Overall, our results suggested that SmQR plays a significant role in salt tolerance and that this gene may be useful for biotechnological development of plants with improved tolerance of salinity. PMID:26541063

  2. Random amplified polymorphic DNA analysis of salt-tolerant tobacco mutants generated by gamma radiation.

    PubMed

    Çelik, Ö; Atak, Ç

    2015-01-01

    Salinity is one of the major problems limiting the yield of agricultural products. Radiation mutagenesis is used to improve salt-tolerant mutant plants. In this study, we aimed to improve salt-tolerant mutants of two oriental tobacco varieties. One thousand seeds of each variety (M₀) were irradiated with 100, 200, 300, and 400 Gy gamma rays by Cs-137 gamma. In the M₁ generation, 2999 single plants were harvested. The next season, these seeds were bulked and planted to obtain M₂ progeny. The seeds of 1900 M₂ plants were picked separately. Salinity tolerance was tested in the M₃ generation. Among M₃ plantlets, 10 salt-tolerant tobacco mutants were selected. According to the results of the selection studies, 100- and 200-Gy gamma radiation doses were the effective doses to obtain the desired mutants. Glutathione reductase enzyme activities of salt-tolerant tobacco mutants were determined biochemically as a stress-tolerance marker. The differences between control and salt-tolerant mutants belonging to the Akhisar 97 and İzmir Özbaş tobacco varieties were evaluated by random amplified polymorphic DNA analysis. The total polymorphism rate was 73.91%. PMID:25730072

  3. 40 CFR 180.1285 - Polyoxin D zinc salt; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Polyoxin D zinc salt; exemption from... FOOD Exemptions From Tolerances § 180.1285 Polyoxin D zinc salt; exemption from the requirement of a... biochemical pesticide polyoxin D zinc when used as a fungicide on almonds, cucurbit vegetables,...

  4. 40 CFR 180.1285 - Polyoxin D zinc salt; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Polyoxin D zinc salt; exemption from... FOOD Exemptions From Tolerances § 180.1285 Polyoxin D zinc salt; exemption from the requirement of a... biochemical pesticide polyoxin D zinc when used as a fungicide on almonds, cucurbit vegetables,...

  5. 40 CFR 180.1285 - Polyoxin D zinc salt; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Polyoxin D zinc salt; exemption from... FOOD Exemptions From Tolerances § 180.1285 Polyoxin D zinc salt; exemption from the requirement of a... biochemical pesticide polyoxin D zinc when used as a fungicide on almonds, cucurbit vegetables,...

  6. Searching in sequences of Leymus BAC clones for genes controlling salt tolerance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many species of Thinopyrum and Leymus are known to be highly salt tolerant. Salinity tolerance in diploid Thinopyrum elongatum, thus all polyploid Thinopyrum species too, is controlled by genes on different chromosomes. Some candidate genes, including genes for peroxidase precursor, for salinity t...

  7. Potassium phosphite increases tolerance to UV-B in potato.

    PubMed

    Soledad, Oyarburo Natalia; Florencia, Machinandiarena Milagros; Laura, Feldman Mariana; Raúl, Daleo Gustavo; Balbina, Andreu Adriana; Pía, Olivieri Florencia

    2015-03-01

    The use of biocompatible chemical compounds that enhance plant disease resistance through Induced Resistance (IR) is an innovative strategy to improve the yield and quality of crops. Phosphites (Phi), inorganic salts of phosphorous acid, are environment friendly, and have been described to induce disease control. Phi, similar to other plant inductors, are thought to be effective against different types of biotic and abiotic stress, and it is assumed that the underlying signaling pathways probably overlap and interact. The signaling pathways triggered by UV-B radiation, for instance, are known to crosstalk with other signaling routes that respond that biotic stress. In the present work, the effect of potassium phosphite (KPhi) pre-treatment on UV-B stress tolerance was evaluated in potato leaves. Plants were treated with KPhi and, after 3 days, exposed to 2 h/day of UV-B (1.5 Watt m(-2)) for 0, 3 and 6 days. KPhi pre-treatment had a beneficial effect on two photosynthetic parameters, specifically chlorophyll content and expression of the psbA gene. Oxidative stress caused by UV-B was also prevented by KPhi. A decrease in the accumulation of hydrogen peroxide (H2O2) in leaves and an increase in guaiacol peroxidase (POD) and superoxide dismutase (SOD) activities were also observed. In addition, the expression levels of a gene involved in flavonoid synthesis increased in UV-B-stressed plants only when pre-treated with KPhi. Finally, accumulation of glucanases and chitinases was induced by UV-B stress and markedly potentiated by KPhi pre-treatment. Altogether, this is the first report that shows a contribution of KPhi in UV-B stress tolerance in potato plants. PMID:25596554

  8. Overexpression of Rat Neurons Nitric Oxide Synthase in Rice Enhances Drought and Salt Tolerance

    PubMed Central

    Cai, Wei; Liu, Wen; Wang, Wen-Shu; Fu, Zheng-Wei; Han, Tong-Tong; Lu, Ying-Tang

    2015-01-01

    Nitric oxide (NO) has been shown to play an important role in the plant response to biotic and abiotic stresses in Arabidopsis mutants with lower or higher levels of endogenous NO. The exogenous application of NO donors or scavengers has also suggested an important role for NO in plant defense against environmental stress. In this study, rice plants under drought and high salinity conditions showed increased nitric oxide synthase (NOS) activity and NO levels. Overexpression of rat neuronal NO synthase (nNOS) in rice increased both NOS activity and NO accumulation, resulting in improved tolerance of the transgenic plants to both drought and salt stresses. nNOS-overexpressing plants exhibited stronger water-holding capability, higher proline accumulation, less lipid peroxidation and reduced electrolyte leakage under drought and salt conditions than wild rice. Moreover, nNOS-overexpressing plants accumulated less H2O2, due to the observed up-regulation of OsCATA, OsCATB and OsPOX1. In agreement, the activities of CAT and POX were higher in transgenic rice than wild type. Additionally, the expression of six tested stress-responsive genes including OsDREB2A, OsDREB2B, OsSNAC1, OsSNAC2, OsLEA3 and OsRD29A, in nNOS-overexpressing plants was higher than that in the wild type under drought and high salinity conditions. Taken together, our results suggest that nNOS overexpression suppresses the stress-enhanced electrolyte leakage, lipid peroxidation and H2O2 accumulation, and promotes proline accumulation and the expression of stress-responsive genes under stress conditions, thereby promoting increased tolerance to drought and salt stresses. PMID:26121399

  9. 40 CFR 180.1068 - C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false C12-C18 fatty acid potassium salts... RESIDUES IN FOOD Exemptions From Tolerances § 180.1068 C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance. C12-C18 fatty acids (saturated and unsaturated) potassium salts...

  10. 40 CFR 180.1068 - C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false C12-C18 fatty acid potassium salts... RESIDUES IN FOOD Exemptions From Tolerances § 180.1068 C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance. C12-C18 fatty acids (saturated and unsaturated) potassium salts...

  11. 40 CFR 180.1068 - C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false C12-C18 fatty acid potassium salts... RESIDUES IN FOOD Exemptions From Tolerances § 180.1068 C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance. C12-C18 fatty acids (saturated and unsaturated) potassium salts...

  12. 40 CFR 180.1068 - C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false C12-C18 fatty acid potassium salts... RESIDUES IN FOOD Exemptions From Tolerances § 180.1068 C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance. C12-C18 fatty acids (saturated and unsaturated) potassium salts...

  13. 40 CFR 180.1068 - C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false C12-C18 fatty acid potassium salts... RESIDUES IN FOOD Exemptions From Tolerances § 180.1068 C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance. C12-C18 fatty acids (saturated and unsaturated) potassium salts...

  14. eHALOPH a Database of Salt-Tolerant Plants: Helping put Halophytes to Work.

    PubMed

    Santos, Joaquim; Al-Azzawi, Mohammed; Aronson, James; Flowers, Timothy J

    2016-01-01

    eHALOPH (http://www.sussex.ac.uk/affiliates/halophytes/) is a database of salt-tolerant plants-halophytes. Records of plant species tolerant of salt concentrations of around 80 mM sodium chloride or more have been collected, along with data on plant type, life form, ecotypes, maximum salinity tolerated, the presence or absence of salt glands, photosynthetic pathway, antioxidants, secondary metabolites, compatible solutes, habitat, economic use and whether there are publications on germination, microbial interactions and mycorrhizal status, bioremediation and of molecular data. The database eHALOPH can be used in the analysis of traits associated with tolerance and for informing choice of species that might be used for saline agriculture, bioremediation or ecological restoration and rehabilitation of degraded wetlands or other areas. PMID:26519912

  15. Native-Invasive Plants vs. Halophytes in Mediterranean Salt Marshes: Stress Tolerance Mechanisms in Two Related Species

    PubMed Central

    Al Hassan, Mohamad; Chaura, Juliana; López-Gresa, María P.; Borsai, Orsolya; Daniso, Enrico; Donat-Torres, María P.; Mayoral, Olga; Vicente, Oscar; Boscaiu, Monica

    2016-01-01

    Dittrichia viscosa is a Mediterranean ruderal species that over the last decades has expanded into new habitats, including coastal salt marshes, ecosystems that are per se fragile and threatened by human activities. To assess the potential risk that this native-invasive species represents for the genuine salt marsh vegetation, we compared its distribution with that of Inula crithmoides, a taxonomically related halophyte, in three salt marshes located in “La Albufera” Natural Park, near the city of Valencia (East Spain). The presence of D. viscosa was restricted to areas of low and moderate salinity, while I. crithmoides was also present in the most saline zones of the salt marshes. Analyses of the responses of the two species to salt and water stress treatments in controlled experiments revealed that both activate the same physiological stress tolerance mechanisms, based essentially on the transport of toxic ions to the leaves—where they are presumably compartmentalized in vacuoles—and the accumulation of specific osmolytes for osmotic adjustment. The two species differ in the efficiency of those mechanisms: salt-induced increases in Na+ and Cl− contents were higher in I. crithmoides than in D. viscosa, and the osmolytes (especially glycine betaine, but also arabinose, fructose and glucose) accumulated at higher levels in the former species. This explains the (slightly) higher stress tolerance of I. crithmoides, as compared to D. viscosa, established from growth inhibition measurements and their distribution in nature. The possible activation of K+ transport to the leaves under high salinity conditions may also contribute to salt tolerance in I. crithmoides. Oxidative stress level—estimated from malondialdehyde accumulation—was higher in the less tolerant D. viscosa, which consequently activated antioxidant responses as a defense mechanism against stress; these responses were weaker or absent in the more tolerant I. crithmoides. Based on these results

  16. Native-Invasive Plants vs. Halophytes in Mediterranean Salt Marshes: Stress Tolerance Mechanisms in Two Related Species.

    PubMed

    Al Hassan, Mohamad; Chaura, Juliana; López-Gresa, María P; Borsai, Orsolya; Daniso, Enrico; Donat-Torres, María P; Mayoral, Olga; Vicente, Oscar; Boscaiu, Monica

    2016-01-01

    Dittrichia viscosa is a Mediterranean ruderal species that over the last decades has expanded into new habitats, including coastal salt marshes, ecosystems that are per se fragile and threatened by human activities. To assess the potential risk that this native-invasive species represents for the genuine salt marsh vegetation, we compared its distribution with that of Inula crithmoides, a taxonomically related halophyte, in three salt marshes located in "La Albufera" Natural Park, near the city of Valencia (East Spain). The presence of D. viscosa was restricted to areas of low and moderate salinity, while I. crithmoides was also present in the most saline zones of the salt marshes. Analyses of the responses of the two species to salt and water stress treatments in controlled experiments revealed that both activate the same physiological stress tolerance mechanisms, based essentially on the transport of toxic ions to the leaves-where they are presumably compartmentalized in vacuoles-and the accumulation of specific osmolytes for osmotic adjustment. The two species differ in the efficiency of those mechanisms: salt-induced increases in Na(+) and Cl(-) contents were higher in I. crithmoides than in D. viscosa, and the osmolytes (especially glycine betaine, but also arabinose, fructose and glucose) accumulated at higher levels in the former species. This explains the (slightly) higher stress tolerance of I. crithmoides, as compared to D. viscosa, established from growth inhibition measurements and their distribution in nature. The possible activation of K(+) transport to the leaves under high salinity conditions may also contribute to salt tolerance in I. crithmoides. Oxidative stress level-estimated from malondialdehyde accumulation-was higher in the less tolerant D. viscosa, which consequently activated antioxidant responses as a defense mechanism against stress; these responses were weaker or absent in the more tolerant I. crithmoides. Based on these results, we

  17. Wheat TaSP gene improves salt tolerance in transgenic Arabidopsis thaliana.

    PubMed

    Ma, Xiaoli; Cui, Weina; Liang, Wenji; Huang, Zhanjing

    2015-12-01

    A novel salt-induced gene with unknown functions was cloned through analysis of gene expression profile of a salt-tolerant wheat mutant RH8706-49 under salt stress. The gene was named Triticum aestivum salt-related protein (TaSP) and deposited in GenBank (Accession No. KF307326). Quantitative polymerase chain reaction (qPCR) results showed that TaSP expression was induced under salt, abscisic acid (ABA), and polyethylene glycol (PEG) stresses. Subcellular localization revealed that TaSP was mainly localized in cell membrane. Overexpression of TaSP in Arabidopsis could improve salt tolerance of 35S::TaSP transgenic Arabidopsis. 35S::TaSP transgenic Arabidopsis lines after salt stress presented better physiological indexes than the control group. In the non-invasive micro-test (NMT), an evident Na(+) excretion was observed at the root tip of salt-stressed 35S::TaSP transgenic Arabidopsis. TaSP promoter was cloned, and its beta-glucuronidase (GUS) activities before and after ABA, salt, cold, heat, and salicylic acid (SA) stresses were determined. Full-length TaSP promoter contained ABA and salt response elements. PMID:26476792

  18. Recent progress in drought and salt tolerance studies in Brassica crops

    PubMed Central

    Zhang, Xuekun; Lu, Guangyuan; Long, Weihua; Zou, Xiling; Li, Feng; Nishio, Takeshi

    2014-01-01

    Water deficit imposed by either drought or salinity brings about severe growth retardation and yield loss of crops. Since Brassica crops are important contributors to total oilseed production, it is urgently needed to develop tolerant cultivars to ensure yields under such adverse conditions. There are various physiochemical mechanisms for dealing with drought and salinity in plants at different developmental stages. Accordingly, different indicators of tolerance to drought or salinity at the germination, seedling, flowering and mature stages have been developed and used for germplasm screening and selection in breeding practices. Classical genetic and modern genomic approaches coupled with precise phenotyping have boosted the unravelling of genes and metabolic pathways conferring drought or salt tolerance in crops. QTL mapping of drought and salt tolerance has provided several dozen target QTLs in Brassica and the closely related Arabidopsis. Many drought- or salt-tolerant genes have also been isolated, some of which have been confirmed to have great potential for genetic improvement of plant tolerance. It has been suggested that molecular breeding approaches, such as marker-assisted selection and gene transformation, that will enhance oil product security under a changing climate be integrated in the development of drought- and salt-tolerant Brassica crops. PMID:24987291

  19. Recent progress in drought and salt tolerance studies in Brassica crops.

    PubMed

    Zhang, Xuekun; Lu, Guangyuan; Long, Weihua; Zou, Xiling; Li, Feng; Nishio, Takeshi

    2014-05-01

    Water deficit imposed by either drought or salinity brings about severe growth retardation and yield loss of crops. Since Brassica crops are important contributors to total oilseed production, it is urgently needed to develop tolerant cultivars to ensure yields under such adverse conditions. There are various physiochemical mechanisms for dealing with drought and salinity in plants at different developmental stages. Accordingly, different indicators of tolerance to drought or salinity at the germination, seedling, flowering and mature stages have been developed and used for germplasm screening and selection in breeding practices. Classical genetic and modern genomic approaches coupled with precise phenotyping have boosted the unravelling of genes and metabolic pathways conferring drought or salt tolerance in crops. QTL mapping of drought and salt tolerance has provided several dozen target QTLs in Brassica and the closely related Arabidopsis. Many drought- or salt-tolerant genes have also been isolated, some of which have been confirmed to have great potential for genetic improvement of plant tolerance. It has been suggested that molecular breeding approaches, such as marker-assisted selection and gene transformation, that will enhance oil product security under a changing climate be integrated in the development of drought- and salt-tolerant Brassica crops. PMID:24987291

  20. Hydrogen Sulfide Regulates Salt Tolerance in Rice by Maintaining Na(+)/K(+) Balance, Mineral Homeostasis and Oxidative Metabolism Under Excessive Salt Stress.

    PubMed

    Mostofa, Mohammad G; Saegusa, Daisuke; Fujita, Masayuki; Tran, Lam-Son Phan

    2015-01-01

    Being a salt sensitive crop, rice growth and development are frequently affected by soil salinity. Hydrogen sulfide (H2S) has been recently explored as an important priming agent regulating diverse physiological processes of plant growth and development. Despite its enormous prospects in plant systems, the role of H2S in plant stress tolerance is still elusive. Here, a combined pharmacological, physiological and biochemical approach was executed aiming to examine the possible mechanism of H2S in enhancement of rice salt stress tolerance. We showed that pretreating rice plants with H2S donor sodium bisulfide (NaHS) clearly improved, but application of H2S scavenger hypotaurine with NaHS decreased growth and biomass-related parameters under salt stress. NaHS-pretreated salt-stressed plants exhibited increased chlorophyll, carotenoid and soluble protein contents, as well as suppressed accumulation of reactive oxygen species (ROS), contributing to oxidative damage protection. The protective mechanism of H2S against oxidative stress was correlated with the elevated levels of ascorbic acid, glutathione, redox states, and the enhanced activities of ROS- and methylglyoxal-detoxifying enzymes. Notably, the ability to decrease the uptake of Na(+) and the Na(+)/K(+) ratio, as well as to balance mineral contents indicated a role of H2S in ion homeostasis under salt stress. Altogether, our results highlight that modulation of the level of endogenous H2S genetically or exogenously could be employed to attain better growth and development of rice, and perhaps other crops, under salt stress. Furthermore, our study reveals the importance of the implication of gasotransmitters like H2S for the management of salt stress, thus assisting rice plants to adapt to adverse environmental changes. PMID:26734015

  1. Hydrogen Sulfide Regulates Salt Tolerance in Rice by Maintaining Na+/K+ Balance, Mineral Homeostasis and Oxidative Metabolism Under Excessive Salt Stress

    PubMed Central

    Mostofa, Mohammad G.; Saegusa, Daisuke; Fujita, Masayuki; Tran, Lam-Son Phan

    2015-01-01

    Being a salt sensitive crop, rice growth and development are frequently affected by soil salinity. Hydrogen sulfide (H2S) has been recently explored as an important priming agent regulating diverse physiological processes of plant growth and development. Despite its enormous prospects in plant systems, the role of H2S in plant stress tolerance is still elusive. Here, a combined pharmacological, physiological and biochemical approach was executed aiming to examine the possible mechanism of H2S in enhancement of rice salt stress tolerance. We showed that pretreating rice plants with H2S donor sodium bisulfide (NaHS) clearly improved, but application of H2S scavenger hypotaurine with NaHS decreased growth and biomass-related parameters under salt stress. NaHS-pretreated salt-stressed plants exhibited increased chlorophyll, carotenoid and soluble protein contents, as well as suppressed accumulation of reactive oxygen species (ROS), contributing to oxidative damage protection. The protective mechanism of H2S against oxidative stress was correlated with the elevated levels of ascorbic acid, glutathione, redox states, and the enhanced activities of ROS- and methylglyoxal-detoxifying enzymes. Notably, the ability to decrease the uptake of Na+ and the Na+/K+ ratio, as well as to balance mineral contents indicated a role of H2S in ion homeostasis under salt stress. Altogether, our results highlight that modulation of the level of endogenous H2S genetically or exogenously could be employed to attain better growth and development of rice, and perhaps other crops, under salt stress. Furthermore, our study reveals the importance of the implication of gasotransmitters like H2S for the management of salt stress, thus assisting rice plants to adapt to adverse environmental changes. PMID:26734015

  2. Using euhalophytes to understand salt tolerance and to develop saline agriculture: Suaeda salsa as a promising model

    PubMed Central

    Song, Jie; Wang, Baoshan

    2015-01-01

    Background As important components in saline agriculture, halophytes can help to provide food for a growing world population. In addition to being potential crops in their own right, halophytes are also potential sources of salt-resistance genes that might help plant breeders and molecular biologists increase the salt tolerance of conventional crop plants. One especially promising halophyte is Suaeda salsa, a euhalophytic herb that occurs both on inland saline soils and in the intertidal zone. The species produces dimorphic seeds: black seeds are sensitive to salinity and remain dormant in light under high salt concentrations, while brown seeds can germinate under high salinity (e.g. 600 mm NaCl) regardless of light. Consequently, the species is useful for studying the mechanisms by which dimorphic seeds are adapted to saline environments. S. salsa has succulent leaves and is highly salt tolerant (e.g. its optimal NaCl concentration for growth is 200 mm). A series of S. salsa genes related to salt tolerance have been cloned and their functions tested: these include SsNHX1, SsHKT1, SsAPX, SsCAT1, SsP5CS and SsBADH. The species is economically important because its fresh branches have high value as a vegetable, and its seed oil is edible and rich in unsaturated fatty acids. Because it can remove salts and heavy metals from saline soils, S. salsa can also be used in the restoration of salinized or contaminated saline land. Scope Because of its economic and ecological value in saline agriculture, S. salsa is one of the most important halophytes in China. In this review, the value of S. salsa as a source of food, medicine and forage is discussed. Its uses in the restoration of salinized or contaminated land and as a source of salt-resistance genes are also considered. PMID:25288631

  3. Knock-out of Arabidopsis AtNHX4 gene enhances tolerance to salt stress

    SciTech Connect

    Li, Hong-Tao; Liu, Hua; Gao, Xiao-Shu; Zhang, Hongxia

    2009-05-08

    AtNHX4 belongs to the monovalent cation:proton antiporter-1 (CPA1) family in Arabidopsis. Several members of this family have been shown to be critical for plant responses to abiotic stress, but little is known on the biological functions of AtNHX4. Here, we provide the evidence that AtNHX4 plays important roles in Arabidopsis responses to salt stress. Expression of AtNHX4 was responsive to salt stress and abscisic acid. Experiments with CFP-AtNHX4 fusion protein indicated that AtNHX4 is vacuolar localized. The nhx4 mutant showed enhanced tolerance to salt stress, and lower Na{sup +} content under high NaCl stress compared with wild-type plants. Furthermore, heterologous expression of AtNHX4 in Escherichia coli BL21 rendered the transformants hypersensitive to NaCl. Deletion of the hydrophilic C-terminus of AtNHX4 dramatically increased the hypersensitivity of transformants, indicating that AtNHX4 may function in Na{sup +} homeostasis in plant cell, and its C-terminus plays a role in regulating the AtNHX4 activity.

  4. Analysis of Antioxidant Enzyme Activity and Antioxidant Genes Expression During Germination of Two Different Genotypes of Lolium multiflorum Under Salt Tolerance.

    PubMed

    Wang, Xia; Ma, Xiao; Xinquan-Zhang; Linkai-Huang; Li, Zhou; Nie, Wenzhi-Xu Gang

    2016-01-01

    Annual ryegrass (Lolium multiflorum) is widely used as a cool-season forage grass for its luxuriant growth, palatable and high digestible. To investigate the salt tolerance mechanism in annual ryegrass under salt stress, salt-tolerant genotype 'R102-3' and salt-sensitive genotype 'Tetragold' were subject to 300mmol/L NaCl in a controlled growth chamber for 12 days. The results showed high concentrations of NaCl decreased relative water content (RWC), and increased the electrolyte leakage (EL) in both genotypes. However the 'Tetragold' had a greater increased extent of malondialdehyde (MDA) and EL than in 'R102-3', in contrast, the activities of Superoxide (SOD), Peroxidase (POD), Catalase (CAT) and Ascorbate peroxidase (APX) were higher in salt resistant compared to sensitive ones. For ensure the accurate of qRT-PCR, we used RefFinder to choose the most stably reference genes eEF1A(s) and GAPDH to normalize the antioxidant genes expression data. The results indicated that higher expression of Fe-SOD, Mn-SOD, Chl-Cu/Zn SOD, Cyt-Cu/Zn SOD, POD and CAT in 'R102-3' when compared with 'Tetragold', which may play an important role in defensed damage of Reactive oxygen species (ROS) under salt stress. Thus, the salt-tolerant genotype could effectively resist oxidative damage induced by salt tress relative to salt-sensitive genotype. PMID:26972970

  5. Expression partitioning of homeologs and tandem duplications contribute to salt tolerance in wheat (Triticum aestivum L.)

    PubMed Central

    Zhang, Yumei; Liu, Zhenshan; Khan, Abul Awlad; Lin, Qi; Han, Yao; Mu, Ping; Liu, Yiguo; Zhang, Hongsheng; Li, Lingyan; Meng, Xianghao; Ni, Zhongfu; Xin, Mingming

    2016-01-01

    Salt stress dramatically reduces crop yield and quality, but the molecular mechanisms underlying salt tolerance remain largely unknown. To explore the wheat transcriptional response to salt stress, we performed high-throughput transcriptome sequencing of 10-day old wheat roots under normal condition and 6, 12, 24 and 48 h after salt stress (HASS) in both a salt-tolerant cultivar and salt-sensitive cultivar. The results demonstrated global gene expression reprogramming with 36,804 genes that were up- or down-regulated in wheat roots under at least one stress condition compared with the controls and revealed the specificity and complexity of the functional pathways between the two cultivars. Further analysis showed that substantial expression partitioning of homeologous wheat genes occurs when the plants are subjected to salt stress, accounting for approximately 63.9% (2,537) and 66.1% (2,624) of the homeologous genes in ‘Chinese Spring’ (CS) and ‘Qing Mai 6’ (QM). Interestingly, 143 salt-responsive genes have been duplicated and tandemly arrayed on chromosomes during wheat evolution and polyploidization events, and the expression patterns of 122 (122/143, 85.3%) tandem duplications diverged dynamically over the time-course of salinity exposure. In addition, constitutive expression or silencing of target genes in Arabidopsis and wheat further confirmed our high-confidence salt stress-responsive candidates. PMID:26892368

  6. Expression partitioning of homeologs and tandem duplications contribute to salt tolerance in wheat (Triticum aestivum L.).

    PubMed

    Zhang, Yumei; Liu, Zhenshan; Khan, Abul Awlad; Lin, Qi; Han, Yao; Mu, Ping; Liu, Yiguo; Zhang, Hongsheng; Li, Lingyan; Meng, Xianghao; Ni, Zhongfu; Xin, Mingming

    2016-01-01

    Salt stress dramatically reduces crop yield and quality, but the molecular mechanisms underlying salt tolerance remain largely unknown. To explore the wheat transcriptional response to salt stress, we performed high-throughput transcriptome sequencing of 10-day old wheat roots under normal condition and 6, 12, 24 and 48 h after salt stress (HASS) in both a salt-tolerant cultivar and salt-sensitive cultivar. The results demonstrated global gene expression reprogramming with 36,804 genes that were up- or down-regulated in wheat roots under at least one stress condition compared with the controls and revealed the specificity and complexity of the functional pathways between the two cultivars. Further analysis showed that substantial expression partitioning of homeologous wheat genes occurs when the plants are subjected to salt stress, accounting for approximately 63.9% (2,537) and 66.1% (2,624) of the homeologous genes in 'Chinese Spring' (CS) and 'Qing Mai 6' (QM). Interestingly, 143 salt-responsive genes have been duplicated and tandemly arrayed on chromosomes during wheat evolution and polyploidization events, and the expression patterns of 122 (122/143, 85.3%) tandem duplications diverged dynamically over the time-course of salinity exposure. In addition, constitutive expression or silencing of target genes in Arabidopsis and wheat further confirmed our high-confidence salt stress-responsive candidates. PMID:26892368

  7. Overexpression of a Chimeric Gene, OsDST-SRDX, Improved Salt Tolerance of Perennial Ryegrass

    PubMed Central

    Cen, Huifang; Ye, Wenxing; Liu, Yanrong; Li, Dayong; Wang, Kexin; Zhang, Wanjun

    2016-01-01

    The Drought and Salt Tolerance gene (DST) encodes a C2H2 zinc finger transcription factor, which negatively regulates salt tolerance in rice (Oryza sativa). Phylogenetic analysis of six homologues of DST genes in different plant species revealed that DST genes were conserved evolutionarily. Here, the rice DST gene was linked to an SRDX domain for gene expression repression based on the Chimeric REpressor gene-Silencing Technology (CRES-T) to make a chimeric gene (OsDST-SRDX) construct and introduced into perennial ryegrass by Agrobacterium-mediated transformation. Integration and expression of the OsDST-SRDX in transgenic plants were tested by PCR and RT-PCR, respectively. Transgenic lines overexpressing the OsDST-SRDX fusion gene showed obvious phenotypic differences and clear resistance to salt-shock and to continuous salt stresses compared to non-transgenic plants. Physiological analyses including relative leaf water content, electrolyte leakage, proline content, malondialdehyde (MDA) content, H2O2 content and sodium and potassium accumulation indicated that the OsDST-SRDX fusion gene enhanced salt tolerance in transgenic perennial ryegrass by altering a wide range of physiological responses. To our best knowledge this study is the first report of utilizing Chimeric Repressor gene-Silencing Technology (CRES-T) in turfgrass and forage species for salt-tolerance improvement. PMID:27251327

  8. Overexpression of a Chimeric Gene, OsDST-SRDX, Improved Salt Tolerance of Perennial Ryegrass.

    PubMed

    Cen, Huifang; Ye, Wenxing; Liu, Yanrong; Li, Dayong; Wang, Kexin; Zhang, Wanjun

    2016-01-01

    The Drought and Salt Tolerance gene (DST) encodes a C2H2 zinc finger transcription factor, which negatively regulates salt tolerance in rice (Oryza sativa). Phylogenetic analysis of six homologues of DST genes in different plant species revealed that DST genes were conserved evolutionarily. Here, the rice DST gene was linked to an SRDX domain for gene expression repression based on the Chimeric REpressor gene-Silencing Technology (CRES-T) to make a chimeric gene (OsDST-SRDX) construct and introduced into perennial ryegrass by Agrobacterium-mediated transformation. Integration and expression of the OsDST-SRDX in transgenic plants were tested by PCR and RT-PCR, respectively. Transgenic lines overexpressing the OsDST-SRDX fusion gene showed obvious phenotypic differences and clear resistance to salt-shock and to continuous salt stresses compared to non-transgenic plants. Physiological analyses including relative leaf water content, electrolyte leakage, proline content, malondialdehyde (MDA) content, H2O2 content and sodium and potassium accumulation indicated that the OsDST-SRDX fusion gene enhanced salt tolerance in transgenic perennial ryegrass by altering a wide range of physiological responses. To our best knowledge this study is the first report of utilizing Chimeric Repressor gene-Silencing Technology (CRES-T) in turfgrass and forage species for salt-tolerance improvement. PMID:27251327

  9. Beneficial soil bacterium Bacillus subtilis (GB03) augments salt tolerance of white clover

    PubMed Central

    Han, Qing-Qing; Lü, Xin-Pei; Bai, Jiang-Ping; Qiao, Yan; Paré, Paul W.; Wang, Suo-Min; Zhang, Jin-Lin; Wu, Yong-Na; Pang, Xiao-Pan; Xu, Wen-Bo; Wang, Zhi-Liang

    2014-01-01

    Soil salinity is an increasingly serious problem worldwide that reduces agricultural output potential. Selected beneficial soil bacteria can promote plant growth and augment tolerance to biotic and abiotic stresses. Bacillus subtilis strain GB03 has been shown to confer growth promotion and abiotic stress tolerance in the model plant Arabidopsis thaliana. Here we examined the effect of this beneficial soil bacterium on salt tolerance in the legume forage crop, white clover. Plants of white clover (Trifolium repens L. cultivar Huia) were grown from seeds with or without soil inoculation of the beneficial soil bacterium Bacillus subtilis GB03 supplemented with 0, 50, 100, or 150 mM NaCl water into soil. Growth parameters, chlorophyll content, malondialdehyde (MDA) content and osmotic potential were monitored during the growth cycle. Endogenous Na+ and K+ contents were determined at the time of harvest. White clover plants grown in GB03-inoculated soil were significantly larger than non-inoculated controls with respect to shoot height, root length, plant biomass, leaf area and chlorophyll content; leaf MDA content under saline condition and leaf osmotic potential under severe salinity condition (150 mM NaCl) were significantly decreased. Furthermore, GB03 significantly decreased shoot and root Na+ accumulation and thereby improved K+/Na+ ratio when GB03-inoculated plants were grown under elevated salt conditions. The results indicate that soil inoculation with GB03 promotes white clover growth under both non-saline and saline conditions by directly or indirectly regulating plant chlorophyll content, leaf osmotic potential, cell membrane integrity and ion accumulation. PMID:25339966

  10. Increasing freezing tolerance: kinase regulation of ICE1.

    PubMed

    Zhan, Xiangqiang; Zhu, Jian-Kang; Lang, Zhaobo

    2015-02-01

    Cold temperatures trigger the ICE1-CBF-COR transcriptional cascade in plants, which reprograms gene expression to increase freezing tolerance. In this issue of Developmental Cell, Ding et al. (2015) report that cold stress activates the protein kinase OST1 to phosphorylate and thereby stabilize and stimulate ICE1. This enhances plant tolerance to freezing temperatures. PMID:25669879

  11. Nonlinear responses in salt marsh functioning to increased nitrogen addition.

    PubMed

    Vivanco, Lucía; Irvine, Irina C; Martiny, Jennifer B H

    2015-04-01

    Salt marshes provide storm protection to shorelines, sequester carbon (C), and mitigate coastal eutrophication. These valuable coastal ecosystems are confronted with increasing nitrogen (N) inputs from anthropogenic sources, such as agricultural runoff, wastewater, and atmospheric deposition. To inform predictions of salt marsh functioning and sustainability in the future, we characterized the response of a variety of plant, microbial, and sediment responses to a seven-level gradient of N addition in three Californian salt marshes after 7 and 14 months of N addition. The marshes showed variable responses to the experimental N gradient that can be grouped as neutral (root biomass, sediment respiration, potential carbon mineralization, and potential net nitrification), linear (increasing methane flux, decreasing potential net N mineralization, and increasing sediment inorganic N), and nonlinear (saturating aboveground plant biomass and leaf N content, and exponentially increasing sediment inorganic and organic N). The three salt marshes showed quantitative differences in most ecosystem properties and processes rates; however, the form of the response curves to N addition were generally consistent across the three marshes, indicating that the responses observed may be applicable to other marshes in the region. Only for sediment properties (inorganic and organic N pool) did the shape of the response differ significantly between marshes. Overall, the study suggests salt marshes are limited in their ability to sequester C and N with future increases in N, even without further losses in marsh area. PMID:26230015

  12. Increase of urban lake salinity by road deicing salt.

    PubMed

    Novotny, Eric V; Murphy, Dan; Stefan, Heinz G

    2008-11-15

    Over 317,000 tonnes of road salt (NaCl) are applied annually for road deicing in the Twin Cities Metropolitan Area (TCMA) of Minnesota. Although road salt is applied to increase driving safety, this practice influences environmental water quality. Thirteen lakes in the TCMA were studied over 46 months to determine if and how they respond to the seasonal applications of road salt. Sodium and chloride concentrations in these lakes were 10 and 25 times higher, respectively, than in other non-urban lakes in the region. Seasonal salinity/chloride cycles in the lakes were correlated with road salt applications: High concentrations in the winter and spring, especially near the bottom of the lakes, were followed by lower concentrations in the summer and fall due to flushing of the lakes by rainfall runoff. The seasonal salt storage/flushing rates for individual lakes were derived from volume-weighted average chloride concentration time series. The rate ranged from 9 to 55% of a lake's minimum salt content. In some of the lakes studied salt concentrations were high enough to stop spring turnover preventing oxygen from reaching the benthic sediments. Concentrations above the sediments were also high enough to induce convective mixing of the saline water into the sediment pore water. A regional analysis of historical water quality records of 38 lakes in the TCMA showed increases in lake salinity from 1984 to 2005 that were highly correlated with the amount of rock salt purchased by the State of Minnesota. Chloride concentrations in individual lakes were positively correlated with the percent of impervious surfaces in the watershed and inversely with lake volume. Taken together, the results show a continuing degradation of the water quality of urban lakes due to application of NaCl in their watersheds. PMID:18762321

  13. Growth of Escherichia coli in human urine: role of salt tolerance and accumulation of glycine betaine.

    PubMed

    Kunin, C M; Hua, T H; Van Arsdale White, L; Villarejo, M

    1992-12-01

    Glycine betaine is a powerful osmoprotectant molecule present in the inner medulla of the kidney and excreted into urine. It may be responsible for the ability of Escherichia coli to grow in hypertonic urine. Also, strains of E. coli that cause urinary tract infections may be more salt-tolerant than strains from other sites. To explore these questions, 301 isolates from blood, urine, or stool and 12 representative enteric strains were examined. Tolerance varied from 0.1 to 0.7 M NaCl (median, 0.5) in minimal medium. There were no significant differences in salt tolerance by site of isolation. A salt-sensitive enteric strain that responded poorly to glycine betaine and mutant strains lacking the ability to synthesize or transport glycine betaine did not grow well in hypertonic urine. Accumulation of glycine betaine appears to be a mechanism by which E. coli can adapt to external osmotic forces and grow in hypertonic urine. PMID:1431248

  14. Aerobic digestion of tannery wastewater in a sequential batch reactor by salt-tolerant bacterial strains

    NASA Astrophysics Data System (ADS)

    Durai, G.; Rajasimman, M.; Rajamohan, N.

    2011-09-01

    Among the industries generating hyper saline effluents, tanneries are prominent in India. Hyper saline wastewater is difficult to treat by conventional biological treatment methods. Salt-tolerant microbes can adapt to these conditions and degrade the organics in hyper saline wastewater. In this study, the performance of a bench scale aerobic sequencing batch reactor (SBR) was investigated to treat the tannery wastewater by the salt-tolerant bacterial strains namely Pseudomonas aeruginosa, Bacillus flexus, Exiguobacterium homiense and Styphylococcus aureus. The study was carried out under different operating conditions by changing the hydraulic retention time, organic loading rate and initial substrate concentration. From the results it was found that a maximum COD reduction of 90.4% and colour removal of 78.6% was attained. From this study it was found that the salt-tolerant microorganisms could improve the reduction efficiency of COD and colour of the tannery wastewater.

  15. Increased sensitivity to salt stress in tocopherol-deficient Arabidopsis mutants growing in a hydroponic system

    PubMed Central

    Ellouzi, Hasna; Hamed, Karim Ben; Cela, Jana; Müller, Maren; Abdelly, Chedly; Munné-Bosch, Sergi

    2013-01-01

    Recent studies suggest that tocopherols could play physiological roles in salt tolerance but the mechanisms are still unknown. In this study, we analyzed changes in growth, mineral and oxidative status in vte1 and vte4 Arabidopsis thaliana mutants exposed to salt stress. vte1 and vte4 mutants lack α-tocopherol, but only the vte1 mutant is additionally deficient in γ-tocopherol. Results showed that a deficiency in vitamin E leads to reduced growth and increased oxidative stress in hydroponically-grown plants. This effect was observed at early stages, not only in rosettes but also in roots. The vte1 mutant was more sensitive to salt-induced oxidative stress than the wild type and the vte4 mutant. Salt sensitivity was associated with (i) high contents of Na+, (ii) reduced efficiency of PSII photochemistry (Fv/Fm ratio) and (iii) more pronounced oxidative stress as indicated by increased hydrogen peroxide and malondialdeyde levels. The vte 4 mutant, which accumulates γ- instead of α-tocopherol showed an intermediate sensitivity to salt stress between the wild type and the vte1 mutant. Contents of abscisic acid, jasmonic acid and the ethylene precursor, 1-aminocyclopropane-1-carboxylic acid were higher in the vte1 mutant than the vte4 mutant and wild type. It is concluded that vitamin E-deficient plants show an increased sensitivity to salt stress both in rosettes and roots, therefore indicating the positive role of tocopherols in stress tolerance, not only by minimizing oxidative stress, but also controlling Na+/K+ homeostasis and hormonal balance. PMID:23299430

  16. Increased sensitivity to salt stress in tocopherol-deficient Arabidopsis mutants growing in a hydroponic system.

    PubMed

    Ellouzi, Hasna; Hamed, Karim Ben; Cela, Jana; Müller, Maren; Abdelly, Chedly; Munné-Bosch, Sergi

    2013-02-01

    Recent studies suggest that tocopherols could play physiological roles in salt tolerance but the mechanisms are still unknown. In this study, we analyzed changes in growth, mineral and oxidative status in vte1 and vte4 Arabidopsis thaliana mutants exposed to salt stress. vte1 and vte4 mutants lack α-tocopherol, but only the vte1 mutant is additionally deficient in γ-tocopherol. Results showed that a deficiency in vitamin E leads to reduced growth and increased oxidative stress in hydroponically-grown plants. This effect was observed at early stages, not only in rosettes but also in roots. The vte1 mutant was more sensitive to salt-induced oxidative stress than the wild type and the vte4 mutant. Salt sensitivity was associated with (i) high contents of Na(+), (ii) reduced efficiency of PSII photochemistry (Fv/Fm ratio) and (iii) more pronounced oxidative stress as indicated by increased hydrogen peroxide and malondialdeyde levels. The vte 4 mutant, which accumulates γ- instead of α-tocopherol showed an intermediate sensitivity to salt stress between the wild type and the vte1 mutant. Contents of abscisic acid, jasmonic acid and the ethylene precursor, 1-aminocyclopropane-1-carboxylic acid were higher in the vte1 mutant than the vte4 mutant and wild type. It is concluded that vitamin E-deficient plants show an increased sensitivity to salt stress both in rosettes and roots, therefore indicating the positive role of tocopherols in stress tolerance, not only by minimizing oxidative stress, but also controlling Na(+)/K(+) homeostasis and hormonal balance. PMID:23299430

  17. Ascorbate peroxidase from Jatropha curcas enhances salt tolerance in transgenic Arabidopsis.

    PubMed

    Chen, Y; Cai, J; Yang, F X; Zhou, B; Zhou, L R

    2015-01-01

    Ascorbate peroxidase (APX) plays a central role in the ascorbate-glutathione cycle and is a key enzyme in cellular H2O2 me-tabolism. It includes a family of isoenzymes with different character-istics, which are identified in many higher plants. In the present study, we isolated the APX gene from Jatropha curcas L, which is similar with other previously characterized APXs as revealed by alignment and phylogenetic analysis of its deduced amino acid sequence. Real-time qPCR analysis showed that the expression level of JcAPX transcript significantly increased under NaCl stress. Subsequently, to elucidate the contribution of JcAPX to the protection against salt-induced oxi-dative stress, the expression construct p35S: JcAPX was created and transformed into Arabidopsis and transcribed. Under 150-mM NaCl stress, compared with wild type (WT), the overexpression of JcAPX in Arabidopsis increased the germination rate, the number of leaves, and the rosette area. In addition, the transgenic plants had longer roots, higher total chlorophyll content, higher total APX activity, and lower H2O2 content than the WT under NaCl stress conditions. These results suggested that higher APX activity in transgenic lines increases the salt tolerance by enhancing scavenging capacity for reactive oxygen spe-cies under NaCl stress conditions. PMID:25966262

  18. The Arabidopsis ceramidase AtACER functions in disease resistance and salt tolerance.

    PubMed

    Wu, Jian-Xin; Li, Jian; Liu, Zhe; Yin, Jian; Chang, Zhen-Yi; Rong, Chan; Wu, Jia-Li; Bi, Fang-Cheng; Yao, Nan

    2015-03-01

    Ceramidases hydrolyze ceramide into sphingosine and fatty acids. In mammals, ceramidases function as key regulators of sphingolipid homeostasis, but little is known about their roles in plants. Here we characterize the Arabidopsis ceramidase AtACER, a homolog of human alkaline ceramidases. The acer-1 T-DNA insertion mutant has pleiotropic phenotypes, including reduction of leaf size, dwarfing and an irregular wax layer, compared with wild-type plants. Quantitative sphingolipid profiling showed that acer-1 mutants and the artificial microRNA-mediated silenced line amiR-ACER-1 have high ceramide levels and decreased long chain bases. AtACER localizes predominantly to the endoplasmic reticulum, and partially to the Golgi complex. Furthermore, we found that acer-1 mutants and AtACER RNAi lines showed increased sensitivity to salt stress, and lines overexpressing AtACER showed increased tolerance to salt stress. Reduction of AtACER also increased plant susceptibility to Pseudomonas syringae. Our data highlight the key biological functions of ceramidases in biotic and abiotic stresses in plants. PMID:25619405

  19. Ecotonal distribution of salt-tolerant shrubs in the northern Mojave Desert

    SciTech Connect

    Romney, E.M.; Wallace, A.

    1980-01-01

    Ecotonal distribution of salt-tolerant shrubs was investigated under different kinds of edaphic conditions common to open and closed drainage basins in the northern Mojave Desert. Contributing causal factors involved changes in soil salinity, texture, and moisture stress. Varying degrees of halophytism occurred, ranging from plant species that are facultative in their adaptation to salinity to those that require comparatively high salt concentrations in soil for normal growth and development.

  20. GmFNSII-controlled soybean flavone metabolism responds to abiotic stresses and regulates plant salt tolerance.

    PubMed

    Yan, Junhui; Wang, Biao; Jiang, Yina; Cheng, Linjing; Wu, Tianlong

    2014-01-01

    Flavones, a major group of flavonoids in most plant tissues, play multiple roles in plant-environment interactions. In our study, the expression of the two soybean flavone synthase genes, GmFNSII-1 and GmFNSII-2, was significantly increased by methyl jasmonate (MeJA), glucose, mannitol and NaCl treatment, which were also found to increase flavone aglycone accumulation in Glycine max (L.) Merrill. In the GmFNSII-1 promoter, a specific CGTCA motif in the region (-979 bp to -806 bp) involved in the MeJA response was identified. Promoter deletion analysis of GmFNSII-2 revealed the presence of osmotic-responsive (-1,143 bp to -767 bp) and glucose-repressive sequence elements (-767 bp to -475 bp), which strongly supported the hypothesis that glucose induces soybean flavone production by acting as both an osmotic factor and a sugar signaling molecule simultaneously. Silencing of the GmFNSII gene clearly reduced the production of flavone aglycones (apigenin, luteolin and 7,4'-dihydroxyflavone) in hairy roots. The GmFNSII-RNAi (RNA interference) roots that had a reduced level of flavones accompanied by more malondialdehyde and H2O2 accumulation were more sensitive to salt stress compared with those of the control, and we concluded that flavones, as antioxidants, are associated with salt tolerance. PMID:24192294

  1. Biodiesel from salt-tolerant seashore mallow (Kosteletzkya virginica)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seashore mallow (Kosteletzkya virginica) is a halophytic perennial dicot that produces up to 1500 kg of seeds (22% oil) per hectare and is tolerant of saline soils and brackish water. FAMEs were prepared in high yield by transesterification of hexane-extracted seashore mallow seed oil. The crude oil...

  2. Increased glutathione contributes to stress tolerance and global translational changes in Arabidopsis.

    PubMed

    Cheng, Mei-Chun; Ko, Ko; Chang, Wan-Ling; Kuo, Wen-Chieh; Chen, Guan-Hong; Lin, Tsan-Piao

    2015-09-01

    Although glutathione is well known for its reactive oxygen species (ROS) scavenging function and plays a protective role in biotic stress, its regulatory function in abiotic stress still remains to be elucidated. Our previous study showed that exogenously applied reduced glutathione (GSH) could improve abiotic stress tolerance in Arabidopsis. Here, we report that endogenously increased GSH also conferred tolerance to drought and salt stress in Arabidopsis. Moreover, both exogenous and endogenous GSH delayed senescence and flowering time. Polysomal profiling results showed that global translation was enhanced after GSH treatment and by the induced increase of GSH level by salt stress. By performing transcriptomic analyses of steady-state and polysome-bound mRNAs in GSH-treated plants, we reveal that GSH has a substantial impact on translation. Translational changes induced by GSH treatment target numerous hormones and stress signaling molecules, which might contribute to the enhanced stress tolerance in GSH-treated plants. Our translatome analysis also revealed that abscisic acid (ABA), auxin and jasmonic acid (JA) biosynthesis, as well as signaling genes, were activated during GSH treatment, which has not been reported in previously published transcriptomic data. Together, our data suggest that the increased glutathione level results in stress tolerance and global translational changes. PMID:26213235

  3. Genetic Linkage Map Construction and QTL Mapping of Salt Tolerance Traits in Zoysiagrass (Zoysia japonica)

    PubMed Central

    Guo, Hailin; Ding, Wanwen; Chen, Jingbo; Chen, Xuan; Zheng, Yiqi; Wang, Zhiyong; Liu, Jianxiu

    2014-01-01

    Zoysiagrass (Zoysia Willd.) is an important warm season turfgrass that is grown in many parts of the world. Salt tolerance is an important trait in zoysiagrass breeding programs. In this study, a genetic linkage map was constructed using sequence-related amplified polymorphism markers and random amplified polymorphic DNA markers based on an F1 population comprising 120 progeny derived from a cross between Zoysia japonica Z105 (salt-tolerant accession) and Z061 (salt-sensitive accession). The linkage map covered 1211 cM with an average marker distance of 5.0 cM and contained 24 linkage groups with 242 marker loci (217 sequence-related amplified polymorphism markers and 25 random amplified polymorphic DNA markers). Quantitative trait loci affecting the salt tolerance of zoysiagrass were identified using the constructed genetic linkage map. Two significant quantitative trait loci (qLF-1 and qLF-2) for leaf firing percentage were detected; qLF-1 at 36.3 cM on linkage group LG4 with a logarithm of odds value of 3.27, which explained 13.1% of the total variation of leaf firing and qLF-2 at 42.3 cM on LG5 with a logarithm of odds value of 2.88, which explained 29.7% of the total variation of leaf firing. A significant quantitative trait locus (qSCW-1) for reduced percentage of dry shoot clipping weight was detected at 44.1 cM on LG5 with a logarithm of odds value of 4.0, which explained 65.6% of the total variation. This study provides important information for further functional analysis of salt-tolerance genes in zoysiagrass. Molecular markers linked with quantitative trait loci for salt tolerance will be useful in zoysiagrass breeding programs using marker-assisted selection. PMID:25203715

  4. Cyclic nucleotide gated channel 10 negatively regulates salt tolerance by mediating Na+ transport in Arabidopsis.

    PubMed

    Jin, Yakang; Jing, Wen; Zhang, Qun; Zhang, Wenhua

    2015-01-01

    A number of cyclic nucleotide gated channel (CNGC) genes have been identified in plant genomes, but their functions are mainly undefined. In this study, we identified the role of CNGC10 in the response of Arabidopsis thaliana to salt stress. The cngc10 T-DNA insertion mutant showed greater tolerance to salt than wild-type A. thaliana during seed germination and seedling growth. The cngc10 mutant accumulated less Na(+) and K(+), but not less Ca(2+), in shoots in response to salt stress. By contrast, overexpression of CNGC10 resulted in greater sensitivity to salt stress, and complementation of this gene recovered salt sensitivity. In response to salt stress, heterologous expression of CNGC10 in the Na(+) sensitive yeast mutant strain B31 inhibited growth due to accumulation of Na(+) at a rate greater than that of yeast transformed with an empty vector. Quantitative RT-PCR analysis demonstrated that CNGC10 was expressed mainly in roots and flowers. GUS analysis of a root cross section indicated that CNGC10 was expressed mainly in the endodermis and epidermis. Furthermore, the expression of CNGC10 in roots was dramatically inhibited by exposure to 200 mM NaCl for 6 h. These data suggest that CNGC10 negatively regulates salt tolerance in A. thaliana and may be involved in mediating Na(+) transport. PMID:25416933

  5. A bi-functional xyloglucan galactosyltransferase is an indispensable salt stress tolerance determinant in Arabidopsis.

    PubMed

    Li, Wenbo; Guan, Qingmei; Wang, Zhen-Yu; Wang, Yingdian; Zhu, Jianhua

    2013-07-01

    Salinity is an abiotic stress that substantially limits crop production worldwide. To identify salt stress tolerance determinants, we screened for Arabidopsis mutants that are hypersensitive to salt stress and designated these mutants as short root in salt medium (rsa). One of these mutants, rsa3-1, is hypersensitive to NaCl and LiCl but not to CsCl or to general osmotic stress. Reactive oxygen species (ROS) over-accumulate in rsa3-1 plants under salt stress. Gene expression profiling with Affymetrix microarray analysis revealed that RSA3 controls expression of many genes including genes encoding proteins for ROS detoxification under salt stress. Map-based cloning showed that RSA3 encodes a xyloglucan galactosyltransferase, which is allelic to a gene previously named MUR3/KAM1. The RSA3/MUR3/KAM1-encoded xylogluscan galactosyltransferase regulates actin microfilament organization (and thereby contributes to endomembrane distribution) and is also involved in cell wall biosynthesis. In rsa3-1, actin cannot assemble and form bundles as it does in the wild-type but instead aggregates in the cytoplasm. Furthermore, addition of phalloidin, which prevents actin depolymerization, can rescue salt hypersensitivity of rsa3-1. Together, these results suggest that RSA3/MUR3/KAM1 along with other cell wall-associated proteins plays a critical role in salt stress tolerance by maintaining the proper organization of actin microfilaments in order to minimize damage caused by excessive ROS. PMID:23571490

  6. Computer-Delivered Social Norm Message Increases Pain Tolerance

    PubMed Central

    Pulvers, Kim; Schroeder, Jacquelyn; Limas, Eleuterio F.; Zhu, Shu-Hong

    2013-01-01

    Background Few experimental studies have been conducted on social determinants of pain tolerance. Purpose This study tests a brief, computer-delivered social norm message for increasing pain tolerance. Methods Healthy young adults (N=260; 44 % Caucasian; 27 % Hispanic) were randomly assigned into a 2 (social norm)×2 (challenge) cold pressor study, stratified by gender. They received standard instructions or standard instructions plus a message that contained artifically elevated information about typical performance of others. Results Those receiving a social norm message displayed significantly higher pain tolerance, F(1, 255)=26.95, p<.001, ηp2=.10 and pain threshold F(1, 244)=9.81, p=.002, ηp2=.04, but comparable pain intensity, p>.05. There were no interactions between condition and gender on any outcome variables, p>.05. Conclusions Social norms can significantly increase pain tolerance, even with a brief verbal message delivered by a video. PMID:24146086

  7. Cloning a glutathione peroxidase gene from Nelumbo nucifera and enhanced salt tolerance by overexpressing in rice.

    PubMed

    Diao, Ying; Xu, Huaxue; Li, Guolin; Yu, Aiqing; Yu, Xia; Hu, Wanling; Zheng, Xingfei; Li, Shaoqing; Wang, Youwei; Hu, Zhongli

    2014-08-01

    A full-length cDNA clone encoding an 866 bp-length glutathione peroxidase protein (NnGPX) was isolated from lotus (Nelumbo nucifera L.). The deduced amino acid sequence of the NnGPX gene had significant homology with ATGPX6. A 3D structural model of the NnGPX was constructed by homology modeling. The cloned NnGPX gene was expressed in Escherichia coli, and a fusion protein of about 40 kDa was detected after isopropyl thiogalactoside induction. Under different concentrations of Na2SeO3 treatments, NnGPX was found to be an enzyme that does not contain selenium. Real-time PCR analysis showed that the NnGPX gene was expressed in all organs of lotus, and its high expression mainly occurred in organs with active metabolisms. NnGPX transcript increased remarkably in response to cold, heat, mechanical damage, and salt treatment. Subsequently, the NnGPX gene was introduced in Oryza sativa cv. Yuetai B. PCR results verified the integration of this gene into the genome of rice and reverse transcription-PCR verified that this gene had been expressed in transgenic rice. The transgenic plants were significantly more tolerant to salt stress compared with the wild-type. PMID:24715609

  8. Tomato salt tolerance: Impact of grafting and water composition on yield and ion relations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We evaluated the salt tolerance of tomato cv Big Dena under both non-grafted 2 conditions and when grafted on Maxifort rootstock, under a series of 5 salinity levels and two irrigation water composition types. The salinity levels of the irrigation water were -0.03, -0.15, -0.30, -0.45, and -0.60 MPa...

  9. COMPARATIVE TRANSCRIPTOME ANALYSIS OF SALT-TOLERANT WHEAT GERMPLASM LINES USING GENOME ARRAYS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salt-tolerant wheat lines W4909 and W4910 were derived from a cross between AJDAj5 (a disomic addition line carrying a pair of Eb chromosomes from Thinopyrum junceum) and Ph1 (a line having the Ph1 allele from Aegilops speltoides, which promotes homoeologous recombination). Both lines have greater ...

  10. Tolerance to road salt deicers in chronically exposed urban pond communities

    EPA Science Inventory

    Freshwater salinization is a concern in urban aquatic ecosystems that receive road salt runoff from vast expanses of impervious surface cover. Our study was designed to evaluate the effects of chloride contamination on urban stormwater pond food webs and to assess the tolerance o...

  11. High Tolerance to Salinity and Herbivory Stresses May Explain the Expansion of Ipomoea Cairica to Salt Marshes

    PubMed Central

    Liu, Gang; Huang, Qiao-Qiao; Lin, Zhen-Guang; Huang, Fang-Fang; Liao, Hui-Xuan; Peng, Shao-Lin

    2012-01-01

    Background Invasive plants are often confronted with heterogeneous environments and various stress factors during their secondary phase of invasion into more stressful habitats. A high tolerance to stress factors may allow exotics to successfully invade stressful environments. Ipomoea cairica, a vigorous invader in South China, has recently been expanding into salt marshes. Methodology/Principal Findings To examine why this liana species is able to invade a stressful saline environment, we utilized I. cairica and 3 non-invasive species for a greenhouse experiment. The plants were subjected to three levels of salinity (i.e., watered with 0, 4 and 8 g L−1 NaCl solutions) and simulated herbivory (0, 25 and 50% of the leaf area excised) treatments. The relative growth rate (RGR) of I. cairica was significantly higher than the RGR of non-invasive species under both stress treatments. The growth performance of I. cairica was not significantly affected by either stress factor, while that of the non-invasive species was significantly inhibited. The leaf condensed tannin content was generally lower in I. cairica than in the non-invasive I. triloba and Paederia foetida. Ipomoea cairica exhibited a relatively low resistance to herbivory, however, its tolerance to stress factors was significantly higher than either of the non-invasive species. Conclusions/Significance This is the first study examining the expansion of I. cairica to salt marshes in its introduced range. Our results suggest that the high tolerance of I. cairica to key stress factors (e.g., salinity and herbivory) contributes to its invasion into salt marshes. For I. cairica, a trade-off in resource reallocation may allow increased resources to be allocated to tolerance and growth. This may contribute to a secondary invasion into stressful habitats. Finally, we suggest that I. cairica could spread further and successfully occupy salt marshes, and countermeasures based on herbivory could be ineffective for

  12. TaCIPK29, a CBL-Interacting Protein Kinase Gene from Wheat, Confers Salt Stress Tolerance in Transgenic Tobacco

    PubMed Central

    Zhou, Shiyi; Zhang, Fan; Han, Jiapeng; Chen, Lihong; Li, Yin; Feng, Jialu; Fang, Bin; Luo, Qingchen; Li, Shasha; Liu, Yunyi; Yang, Guangxiao; He, Guangyuan

    2013-01-01

    Calcineurin B-like protein-interacting protein kinases (CIPKs) have been found to be responsive to abiotic stress. However, their precise functions and the related molecular mechanisms in abiotic stress tolerance are not completely understood, especially in wheat. In the present study, TaCIPK29 was identified as a new member of CIPK gene family in wheat. TaCIPK29 transcript increased after NaCl, cold, methyl viologen (MV), abscisic acid (ABA) and ethylene treatments. Over-expression of TaCIPK29 in tobacco resulted in increased salt tolerance, which was demonstrated by higher germination rates, longer root lengths and better growth status of transgenic tobacco plants compared to controls when both were treated with salt stress. Physiological measurements indicated that transgenic tobacco seedlings retained high K+/Na+ ratios and Ca2+ content by up-regulating some transporter genes expression and also possessed lower H2O2 levels and reduced membrane injury by increasing the expression and activities of catalase (CAT) and peroxidase (POD) under salt stress. Moreover, transgenic lines conferred tolerance to oxidative stress by increasing the activity and expression of CAT. Finally, TaCIPK29 was located throughout cells and it preferentially interacted with TaCBL2, TaCBL3, NtCBL2, NtCBL3 and NtCAT1. Taken together, our results showed that TaCIPK29 functions as a positive factor under salt stress and is involved in regulating cations and reactive oxygen species (ROS) homeostasis. PMID:23922838

  13. Proteomic Analyses Reveal the Mechanism of Dunaliella salina Ds-26-16 Gene Enhancing Salt Tolerance in Escherichia coli

    PubMed Central

    Wang, Yanlong; Hu, Bin; Du, Shipeng; Gao, Shan; Chen, Xiwen; Chen, Defu

    2016-01-01

    We previously screened the novel gene Ds-26-16 from a 4 M salt-stressed Dunaliella salina cDNA library and discovered that this gene conferred salt tolerance to broad-spectrum organisms, including E. coli (Escherichia coli), Haematococcus pluvialis and tobacco. To determine the mechanism of this gene conferring salt tolerance, we studied the proteome of E. coli overexpressing the full-length cDNA of Ds-26-16 using the iTRAQ (isobaric tags for relative and absolute quantification) approach. A total of 1,610 proteins were identified, which comprised 39.4% of the whole proteome. Of the 559 differential proteins, 259 were up-regulated and 300 were down-regulated. GO (gene ontology) and KEGG (Kyoto encyclopedia of genes and genomes) enrichment analyses identified 202 major proteins, including those involved in amino acid and organic acid metabolism, energy metabolism, carbon metabolism, ROS (reactive oxygen species) scavenging, membrane proteins and ABC (ATP binding cassette) transporters, and peptidoglycan synthesis, as well as 5 up-regulated transcription factors. Our iTRAQ data suggest that Ds-26-16 up-regulates the transcription factors in E. coli to enhance salt resistance through osmotic balance, energy metabolism, and oxidative stress protection. Changes in the proteome were also observed in E. coli overexpressing the ORF (open reading frame) of Ds-26-16. Furthermore, pH, nitric oxide and glycerol content analyses indicated that Ds-26-16 overexpression increases nitric oxide content but has no effect on glycerol content, thus confirming that enhanced nitric oxide synthesis via lower intercellular pH was one of the mechanisms by which Ds-26-16 confers salt tolerance to E. coli. PMID:27135411

  14. Proteomic Analyses Reveal the Mechanism of Dunaliella salina Ds-26-16 Gene Enhancing Salt Tolerance in Escherichia coli.

    PubMed

    Wang, Yanlong; Hu, Bin; Du, Shipeng; Gao, Shan; Chen, Xiwen; Chen, Defu

    2016-01-01

    We previously screened the novel gene Ds-26-16 from a 4 M salt-stressed Dunaliella salina cDNA library and discovered that this gene conferred salt tolerance to broad-spectrum organisms, including E. coli (Escherichia coli), Haematococcus pluvialis and tobacco. To determine the mechanism of this gene conferring salt tolerance, we studied the proteome of E. coli overexpressing the full-length cDNA of Ds-26-16 using the iTRAQ (isobaric tags for relative and absolute quantification) approach. A total of 1,610 proteins were identified, which comprised 39.4% of the whole proteome. Of the 559 differential proteins, 259 were up-regulated and 300 were down-regulated. GO (gene ontology) and KEGG (Kyoto encyclopedia of genes and genomes) enrichment analyses identified 202 major proteins, including those involved in amino acid and organic acid metabolism, energy metabolism, carbon metabolism, ROS (reactive oxygen species) scavenging, membrane proteins and ABC (ATP binding cassette) transporters, and peptidoglycan synthesis, as well as 5 up-regulated transcription factors. Our iTRAQ data suggest that Ds-26-16 up-regulates the transcription factors in E. coli to enhance salt resistance through osmotic balance, energy metabolism, and oxidative stress protection. Changes in the proteome were also observed in E. coli overexpressing the ORF (open reading frame) of Ds-26-16. Furthermore, pH, nitric oxide and glycerol content analyses indicated that Ds-26-16 overexpression increases nitric oxide content but has no effect on glycerol content, thus confirming that enhanced nitric oxide synthesis via lower intercellular pH was one of the mechanisms by which Ds-26-16 confers salt tolerance to E. coli. PMID:27135411

  15. GmCLC1 Confers Enhanced Salt Tolerance through Regulating Chloride Accumulation in Soybean

    PubMed Central

    Wei, Peipei; Wang, Longchao; Liu, Ailin; Yu, Bingjun; Lam, Hon-Ming

    2016-01-01

    The family of chloride channel proteins that mediate Cl- transportation play vital roles in plant nutrient supply, cellular action potential and turgor pressure adjustment, stomatal movement, hormone signal recognition and transduction, Cl- homeostasis, and abiotic and biotic stress tolerance. The anionic toxicity, mainly caused by chloride ions (Cl-), on plants under salt stress remains poorly understood. In this work, we investigated the function of soybean Cl-/H+ antiporter GmCLC1 under salt stress in transgenic Arabidopsis thaliana, soybean, and yeast. We found that GmCLC1 enhanced salt tolerance in transgenic A. thaliana by reducing the Cl- accumulation in shoots and hence released the negative impact of salt stress on plant growth. Overexpression of GmCLC1 in the hairy roots of soybean sequestered more Cl- in their roots and transferred less Cl- to their shoots, leading to lower relative electrolyte leakage values in the roots and leaves. When either the soybean GmCLC1 or the yeast chloride transporter gene, GEF1, was transformed into the yeast gef1 mutant, and then treated with different chloride salts (MnCl2, KCl, NaCl), enhanced survival rate was observed. The result indicates that GmCLC1 and GEF1 exerted similar effects on alleviating the stress of diverse chloride salts on the yeast gef1 mutant. Together, this work suggests a protective function of GmCLC1 under Cl- stress. PMID:27504114

  16. GmCLC1 Confers Enhanced Salt Tolerance through Regulating Chloride Accumulation in Soybean.

    PubMed

    Wei, Peipei; Wang, Longchao; Liu, Ailin; Yu, Bingjun; Lam, Hon-Ming

    2016-01-01

    The family of chloride channel proteins that mediate Cl(-) transportation play vital roles in plant nutrient supply, cellular action potential and turgor pressure adjustment, stomatal movement, hormone signal recognition and transduction, Cl(-) homeostasis, and abiotic and biotic stress tolerance. The anionic toxicity, mainly caused by chloride ions (Cl(-)), on plants under salt stress remains poorly understood. In this work, we investigated the function of soybean Cl(-)/H(+) antiporter GmCLC1 under salt stress in transgenic Arabidopsis thaliana, soybean, and yeast. We found that GmCLC1 enhanced salt tolerance in transgenic A. thaliana by reducing the Cl(-) accumulation in shoots and hence released the negative impact of salt stress on plant growth. Overexpression of GmCLC1 in the hairy roots of soybean sequestered more Cl(-) in their roots and transferred less Cl(-) to their shoots, leading to lower relative electrolyte leakage values in the roots and leaves. When either the soybean GmCLC1 or the yeast chloride transporter gene, GEF1, was transformed into the yeast gef1 mutant, and then treated with different chloride salts (MnCl2, KCl, NaCl), enhanced survival rate was observed. The result indicates that GmCLC1 and GEF1 exerted similar effects on alleviating the stress of diverse chloride salts on the yeast gef1 mutant. Together, this work suggests a protective function of GmCLC1 under Cl(-) stress. PMID:27504114

  17. Selection of salt and boron tolerant selenium hyperaccumulator Stanleya pinnata genotypes and characterization of Se phytoremediation from agricultural drainage sediments.

    PubMed

    Freeman, John L; Bañuelos, Gary S

    2011-11-15

    Genetic variation in salt (Na(2)SO(4), NaCl) and boron (B) tolerance among four ecotypes of the selenium (Se) hyperaccumulator Stanleya pinnata (Pursh) Britton was utilized to select tolerant genotypes capable of phytoremediating Se from salt, B, and Se-laden agricultural drainage sediment. The few individual salt/B tolerant genotypes were successfully selected from among a large population of highly salt/B sensitive seedlings. The distribution, hyperaccumulation, and volatilization of Se were then examined in selected plants capable of tolerating the high salt/B laden drainage sediment. Salt/B tolerant genotypes from each of the four ecotypes had mean Se concentrations ranging from 2510 ± 410 to 1740 ± 620 in leaves and 3180 ± 460 to 2500 ± 1060 in seeds (μg Se g(-1) DW ± SD), while average daily Se volatilization rates ranged from 722 ± 375 to 1182 ± 575 (μg Se m(-2) d(-1) ± SD). After two growing seasons (∼18 months), we estimated that hyperaccumulation and volatilization of Se by tolerant S. pinnata genotypes and their associated microbes can remove approximately 30% of the total soil Se in 0-30 cm sediment. The salt/B tolerant S. pinnata genotypes selected and characterized herein represent promising new tools for the successful phytoremediation of Se from salt/B and Se-laden agricultural drainage sediments. PMID:21988205

  18. Physiological, Anatomical and Metabolic Implications of Salt Tolerance in the Halophyte Salvadora persica under Hydroponic Culture Condition.

    PubMed

    Parida, Asish K; Veerabathini, Sairam K; Kumari, Asha; Agarwal, Pradeep K

    2016-01-01

    Salt tolerance mechanism of an extreme halophyte Salvadora persica was assessed by analyzing growth, nutrient uptake, anatomical modifications and alterations in levels of some organic metabolites in seedlings imposed to various levels of salinity (0, 250, 500, and 750 mM NaCl) under hydroponic culture condition. After 21 days of salt treatment, plant height, leaf area, and shoot biomass decreased with increase in salinity whereas the leaf succulence increased significantly with increasing salinity in S. persica. The RWC% of leaf increased progressively in salt-treated seedlings as compared to control. Na(+) contents of leaf, stem and root increased in dose-dependent manner whereas there was no significant changes in K(+) content. There was significant alterations in leaf, stem, and root anatomy by salinity. The thickness of epidermis and spongy parenchyma of leaf increased in salt treated seedlings as compared to control, whereas palisade parenchyma decreased dramatically in extreme salinity (750 mM NaCl). There was a significant reduction in stomatal density and stomatal pore area of leaf with increasing salinity. Anatomical observations of stem showed that the epidermal cells diameter and thickness of cortex decreased by salinity whereas thickness of hypodermal layer, diameter of hypodermal cell, pith area and pith cell diameter increased by high salinity. The root anatomy showed an increase in epidermal thickness by salinity whereas diameters of epidermal cells and xylem vessels decreased. Total soluble sugar content remained unchanged at all levels of salinity whereas reducing sugar content increased by twofold at high salinity (750 mM NaCl). The starch content of leaf decreased progressively in NaCl treated seedlings as compared to control. Total free amino acid content did not change at low salinity (250 mM), whereas it increased significantly at higher salinity (500 and 750 mM NaCl). The proline content increased in NaCl treated seedlings as compared to

  19. Physiological, Anatomical and Metabolic Implications of Salt Tolerance in the Halophyte Salvadora persica under Hydroponic Culture Condition

    PubMed Central

    Parida, Asish K.; Veerabathini, Sairam K.; Kumari, Asha; Agarwal, Pradeep K.

    2016-01-01

    Salt tolerance mechanism of an extreme halophyte Salvadora persica was assessed by analyzing growth, nutrient uptake, anatomical modifications and alterations in levels of some organic metabolites in seedlings imposed to various levels of salinity (0, 250, 500, and 750 mM NaCl) under hydroponic culture condition. After 21 days of salt treatment, plant height, leaf area, and shoot biomass decreased with increase in salinity whereas the leaf succulence increased significantly with increasing salinity in S. persica. The RWC% of leaf increased progressively in salt-treated seedlings as compared to control. Na+ contents of leaf, stem and root increased in dose-dependent manner whereas there was no significant changes in K+ content. There was significant alterations in leaf, stem, and root anatomy by salinity. The thickness of epidermis and spongy parenchyma of leaf increased in salt treated seedlings as compared to control, whereas palisade parenchyma decreased dramatically in extreme salinity (750 mM NaCl). There was a significant reduction in stomatal density and stomatal pore area of leaf with increasing salinity. Anatomical observations of stem showed that the epidermal cells diameter and thickness of cortex decreased by salinity whereas thickness of hypodermal layer, diameter of hypodermal cell, pith area and pith cell diameter increased by high salinity. The root anatomy showed an increase in epidermal thickness by salinity whereas diameters of epidermal cells and xylem vessels decreased. Total soluble sugar content remained unchanged at all levels of salinity whereas reducing sugar content increased by twofold at high salinity (750 mM NaCl). The starch content of leaf decreased progressively in NaCl treated seedlings as compared to control. Total free amino acid content did not change at low salinity (250 mM), whereas it increased significantly at higher salinity (500 and 750 mM NaCl). The proline content increased in NaCl treated seedlings as compared to control

  20. Salinity affects production and salt tolerance of dimorphic seeds of Suaeda salsa.

    PubMed

    Wang, Fengxia; Xu, Yan-Ge; Wang, Shuai; Shi, Weiwei; Liu, Ranran; Feng, Gu; Song, Jie

    2015-10-01

    The effect of salinity on brown seeds/black seeds ratio, seed weight, endogenous hormone concentrations, and germination of brown and black seeds in the euhalophyte Suaeda salsa was investigated. The brown seeds/black seeds ratio, seed weight of brown and black seeds and the content of protein increased at a concentration of 500 mM NaCl compared to low salt conditions (1 mM NaCl). The germination percentage and germination index of brown seeds from plants cultured in 500 mM NaCl were higher than those cultured in 1 mM NaCl, but it was not true for black seeds. The concentrations of IAA (indole-3-acetic acid), ZR (free zeatin riboside) and ABA (abscisic acid) in brown seeds were much greater than those in black seeds, but there were no differences in the level of GAs (gibberellic acid including GA1 and GA3) regardless of the degree of salinity. Salinity during plant culture increased the concentration of GAs, but salinity had no effect on the concentrations of the other three endogenous hormones in brown seeds. Salinity had no effect on the concentration of IAA but increased the concentrations of the other three endogenous hormones in black seeds. Accumulation of endogenous hormones at different concentrations of NaCl during plant growth may be related to seed development and to salt tolerance of brown and black S. salsa seeds. These characteristics may help the species to ensure seedling establishment and population succession in variable saline environments. PMID:26184090

  1. Elevated compartmentalization of Na+ into vacuoles improves salt and cold stress tolerance in sweet potato (Ipomoea batatas).

    PubMed

    Fan, Weijuan; Deng, Gaifang; Wang, Hongxia; Zhang, Hongxia; Zhang, Peng

    2015-08-01

    Salinity and low temperature are the main limiting factors for sweet potato (Ipomoea batatas) growth and agricultural productivity. Various studies have shown that plant NHX-type antiporter plays a crucial role in regulating plant tolerance to salt stress by intracellular Na(+) compartmentalization. The Arabidopsis thaliana AtNHX1 gene that encodes a vacuolar Na(+) /H(+) antiporter was introduced into the sweet potato cultivar Xushu-22 by Agrobacterium-mediated transformation to confer abiotic stress tolerance. Stable insertion of AtNHX1 into the sweet potato genome and its expression was confirmed by Southern blot and reverse transcription-polymerase chain reaction (RT-PCR). A remarkably higher Na(+) /H(+) exchange activity of tonoplast membrane from transgenic sweet potato lines (NOE) in comparison with wild-type (WT) plants confirmed the vacuolar antiporter function in mediating Na(+) /H(+) exchange. Under salt stress, NOE plants accumulated higher Na(+) and K(+) levels in their tissues compared with WT plants, maintaining high K(+) /Na(+) ratios. Consequently, NOE plants showed enhanced protection against cell damage due to the increased proline accumulation, preserved cell membrane integrity, enhanced reactive oxygen species (ROS) scavenging (e.g. increased superoxide dismutase activity), and reduced H2 O2 and malondialdehyde (MDA) production. Moreover, the transgenic plants showed improved cold tolerance through multiple mechanisms of action, revealing the first molecular evidence for NHX1 function in cold response. The transgenic plants showed better biomass production and root yield under stressful conditions. These findings demonstrate that overexpressing AtNHX1 in sweet potato renders the crop tolerant to both salt and cold stresses, providing a greater capacity for the use of AtNHX1 in improving crop performance under combined abiotic stress conditions. PMID:25307930

  2. Pain tolerance selectively increased by a sweet-smelling odor.

    PubMed

    Prescott, John; Wilkie, Jenell

    2007-04-01

    The mechanism underlying reported analgesic effects of odors in humans is unclear, although odor hedonics has been implicated. We tested whether odors that are sweet smelling through prior association with tasted sweetness might influence pain by activating the same analgesic mechanisms as sweet tastes. Inhalation of a sweet-smelling odor during a cold-pressor test increased tolerance for pain compared with inhalation of pleasant and unpleasant low-sweetness odors and no odor. There were no significant differences in pain ratings among the odor conditions. These results suggest that smelled sweetness can produce a naturally occurring conditioned increase in pain tolerance. PMID:17470253

  3. Characterization of an extremely salt-tolerant and thermostable phytase from Bacillus amyloliquefaciens US573.

    PubMed

    Boukhris, Ines; Farhat-Khemakhem, Ameny; Blibech, Monia; Bouchaala, Kameleddine; Chouayekh, Hichem

    2015-09-01

    The extracellular phytase produced by the Bacillus amyloliquefaciens US573 strain, isolated from geothermal soil located in Southern Tunisia was purified and characterized. This calcium-dependent and bile-stable enzyme (PHY US573) was optimally active at pH 7.5 and 70 °C. It showed a good stability at pH ranging from 4 to 10, and especially, an exceptional thermostability as it recovered 50 and 62% of activity after heating for 10 min at 100 and 90 °C, respectively. In addition, PHY US573 was found to be extremely salt-tolerant since it preserved 80 and 95% of activity in the presence of 20 g/l of NaCl and LiCl, respectively. The gene corresponding to PHY US573 was cloned. It encodes a 383 amino acids polypeptide exhibiting 99% identity with the highly thermostable phytases from Bacillus sp. MD2 and B. amyloliquefaciens DS11 (3 and 5 residues difference, respectively), suggesting the existence of common molecular determinants responsible for their remarkable heat stability. Overall, our findings illustrated that in addition to its high potential for application in feed industry, the salt tolerance of the PHY US573 phytase, may represent an exciting new avenue for improvement of phosphorus-use efficiency of salt-tolerant plants in soils with high salt and phytate content. PMID:26188308

  4. (p)ppGpp-dependent and -independent pathways for salt tolerance in Escherichia coli.

    PubMed

    Tarusawa, Takefusa; Ito, Shion; Goto, Simon; Ushida, Chisato; Muto, Akira; Himeno, Hyouta

    2016-07-01

    Addition of some kinds of translation inhibitors targeting the ribosome such as kasugamycin to the culture medium as well as removal of a ribosome maturation factor or a ribosomal protein provides Escherichia coli cells with tolerance to high salt stress. Here, we found that another kind of translation inhibitor, serine hydroxamate (SHX), which induces amino acid starvation leading to (p)ppGpp production, also has a similar effect, but via a different pathway. Unlike kasugamycin, SHX was not effective in (p)ppGpp-null mutant cells. SHX and depletion of RsgA, a ribosome maturation factor, had an additive effect on salt tolerance, while kasugamycin or depletion of RsgA did not. These results indicate the presence of two distinct pathways, (p)ppGpp-dependent and -independent pathways, for salt tolerance of E. coli cell. Both pathways operate even in the absence of σ(S), an alternative sigma factor involved in the stationary phase or stress response. Hastened activation of the exocytoplasmic stress-specific sigma factor, σ(E), after salt shock was observed in the cells treated with SHX, as has been observed in the cells treated with a translation inhibitor or depleted of a ribosome maturation factor. PMID:26823481

  5. Salt tolerance research in date palm tree (Phoenix dactylifera L.), past, present, and future perspectives.

    PubMed

    Yaish, Mahmoud W; Kumar, Prakash P

    2015-01-01

    The date palm can adapt to extreme drought, to heat, and to relatively high levels of soil salinity. However, excessive amounts of salt due to irrigation with brackish water lead to a significant reduction in the productivity of the fruits as well as marked decrease in the viable numbers of the date palm trees. It is imperative that the nature of the existing salt-adaptation mechanism be understood in order to develop future date palm varieties that can tolerate excessive soil salinity. In this perspective article, several research strategies, obstacles, and precautions are discussed in light of recent advancements accomplished in this field and the properties of this species. In addition to a physiological characterization, we propose the use of a full range of OMICS technologies, coupled with reverse genetics approaches, aimed toward understanding the salt-adaption mechanism in the date palm. Information generated by these analyses should highlight transcriptional and posttranscriptional modifications controlling the salt-adaptation mechanisms. As an extremophile with a natural tolerance for a wide range of abiotic stresses, the date palm may represent a treasure trove of novel genetic resources for salinity tolerance. PMID:26042137

  6. Salt tolerance research in date palm tree (Phoenix dactylifera L.), past, present, and future perspectives

    PubMed Central

    Yaish, Mahmoud W.; Kumar, Prakash P.

    2015-01-01

    The date palm can adapt to extreme drought, to heat, and to relatively high levels of soil salinity. However, excessive amounts of salt due to irrigation with brackish water lead to a significant reduction in the productivity of the fruits as well as marked decrease in the viable numbers of the date palm trees. It is imperative that the nature of the existing salt-adaptation mechanism be understood in order to develop future date palm varieties that can tolerate excessive soil salinity. In this perspective article, several research strategies, obstacles, and precautions are discussed in light of recent advancements accomplished in this field and the properties of this species. In addition to a physiological characterization, we propose the use of a full range of OMICS technologies, coupled with reverse genetics approaches, aimed toward understanding the salt-adaption mechanism in the date palm. Information generated by these analyses should highlight transcriptional and posttranscriptional modifications controlling the salt-adaptation mechanisms. As an extremophile with a natural tolerance for a wide range of abiotic stresses, the date palm may represent a treasure trove of novel genetic resources for salinity tolerance. PMID:26042137

  7. Yeast Irc22 Is a Novel Dsk2-Interacting Protein that Is Involved in Salt Tolerance

    PubMed Central

    Ishii, Takashi; Funakoshi, Minoru; Kobayashi, Hideki; Sekiguchi, Takeshi

    2014-01-01

    The yeast ubiquitin-like and ubiquitin-associated protein Dsk2 is one of the ubiquitin receptors that function in the ubiquitin-proteasome pathway. We screened the Dsk2-interacting proteins in Saccharomyces cerevisiae by a two-hybrid assay and identified a novel Dsk2-interacting protein, Irc22, the gene locus of which has previously been described as YEL001C, but the function of which is unknown. IRC22/YEL001C encodes 225 amino acid residues with a calculated molecular weight of 25 kDa. The Irc22 protein was detected in yeast cells. IRC22 was a nonessential gene for yeast growth, and its homologs were found among ascomycetous yeasts. Irc22 interacted with Dsk2 in yeast cells, but not with Rad23 and Ddi1. Ubiquitin-dependent degradation was impaired mildly by over-expression or disruption of IRC22. Compared with the wild-type strain, dsk2Δ exhibited salt sensitivity while irc22Δ exhibited salt tolerance at high temperatures. The salt-tolerant phenotype that was observed in irc22Δ disappeared in the dsk2Δirc22Δ double disruptant, indicating that DSK2 is positively and IRC22 is negatively involved in salt stress tolerance. IRC22 disruption did not affect any responses to DNA damage and oxidative stress when comparing the irc22Δ and wild-type strains. Collectively, these results suggest that Dsk2 and Irc22 are involved in salt stress tolerance in yeast. PMID:24709957

  8. Suppression of PCD-related genes affects salt tolerance in Arabidopsis.

    PubMed

    Bahieldin, Ahmed; Alqarni, Dhafer A M; Atef, Ahmed; Gadalla, Nour O; Al-Matary, Mohammed; Edris, Sherif; Al-Kordy, Magdy A; Makki, Rania M; Al-Doss, Abdullah A; Sabir, Jamal S M; Mutwakil, Mohammed H Z; El-Domyati, Fotouh M

    2016-01-01

    This work aims at examining a natural exciting phenomenon suggesting that suppression of genes inducing programmed cell death (PCD) might confer tolerance against abiotic stresses in plants. PCD-related genes were induced in tobacco under oxalic acid (OA) treatment (20mM), and plant cells were characterized to confirm the incidence of PCD. The results indicated that PCD was triggered 24h after the exposure to OA. Then, RNAs were extracted from tobacco cells 0, 2, 6, 12 and 24h after treatment for deep sequencing. RNA-Seq analyses were done with a special emphasis to clusters whose PCD-related genes were upregulated after 2h of OA exposure. Accordingly, 23 tobacco PCD-related genes were knocked down via virus-induced gene silencing (VIGS), whereas our results indicated the influence of five of them on inducing or suppressing PCD. Knockout T-DNA insertion mutants of these five genes in Arabidopsis were tested under salt stress (0, 100, 150, and 200mM NaCl), and the results indicated that a mutant of an antiapoptotic gene, namely Bax Inhibitor-1 (BI-1), whose VIGS induced PCD in tobacco, was salt sensitive, while a mutant of an apoptotic gene, namely mildew resistance locus O (Mlo), whose VIGS suppressed PCD, was salt tolerant as compared to the WT (Col) control. These data support our hypothesis that retarding PCD-inducing genes can result in higher levels of salt tolerance, while retarding PCD-suppressing genes can result in lower levels of salt tolerance in plants. PMID:27052474

  9. Comparative Proteomics of Thellungiella halophila Leaves from Plants Subjected to Salinity Reveals the Importance of Chloroplastic Starch and Soluble Sugars in Halophyte Salt Tolerance*

    PubMed Central

    Wang, Xuchu; Chang, Lili; Wang, Baichen; Wang, Dan; Li, Pinghua; Wang, Limin; Yi, Xiaoping; Huang, Qixing; Peng, Ming; Guo, Anping

    2013-01-01

    Thellungiella halophila, a close relative of Arabidopsis, is a model halophyte used to study plant salt tolerance. The proteomic/physiological/transcriptomic analyses of Thellungiella plant leaves subjected to different salinity levels, reported herein, indicate an extraordinary ability of Thellungiella to adapt to large concentrations of exogenous saline by compartmentalizing Na+ into cell vacuoles and accumulating proline and soluble sugars as organic osmolytes. Salinity stress stimulated the accumulation of starch in chloroplasts, which resulted in a greatly increased content of starch and total sugars in leaves. Comparative proteomics of Thellungiella leaves identified 209 salt-responsive proteins. Among these, the sequences of 108 proteins were strongly homologous to Arabidopsis protein sequences, and 30 had previously been identified as Thellungiella proteins. Functional classification of these proteins into 16 categories indicated that the majority are involved in carbohydrate metabolism, followed by those involved in energy production and conversion, and then those involved in the transport of inorganic ions. Pathway analysis revealed that most of the proteins are involved in starch and sucrose metabolism, carbon fixation, photosynthesis, and glycolysis. Of these processes, the most affected were starch and sucrose metabolism, which might be pivotal for salt tolerance. The gene expression patterns of the 209 salt-responsive proteins revealed through hierarchical clustering of microarray data and the expression patterns of 29 Thellungiella genes evaluated via quantitative RT-PCR were similar to those deduced via proteomic analysis, which underscored the possibility that starch and sucrose metabolism might play pivotal roles in determining the salt tolerance ability of Thellungiella. Our observations enabled us to propose a schematic representation of the systematic salt-tolerance phenotype in Thellungiella and suggested that the increased accumulation of

  10. Quantitative Proteomics of the Tonoplast Reveals a Role for Glycolytic Enzymes in Salt Tolerance[C][W

    PubMed Central

    Barkla, Bronwyn J.; Vera-Estrella, Rosario; Hernández-Coronado, Marcela; Pantoja, Omar

    2009-01-01

    To examine the role of the tonoplast in plant salt tolerance and identify proteins involved in the regulation of transporters for vacuolar Na+ sequestration, we exploited a targeted quantitative proteomics approach. Two-dimensional differential in-gel electrophoresis analysis of free flow zonal electrophoresis separated tonoplast fractions from control, and salt-treated Mesembryanthemum crystallinum plants revealed the membrane association of glycolytic enzymes aldolase and enolase, along with subunits of the vacuolar H+-ATPase V-ATPase. Protein blot analysis confirmed coordinated salt regulation of these proteins, and chaotrope treatment indicated a strong tonoplast association. Reciprocal coimmunoprecipitation studies revealed that the glycolytic enzymes interacted with the V-ATPase subunit B VHA-B, and aldolase was shown to stimulate V-ATPase activity in vitro by increasing the affinity for ATP. To investigate a physiological role for this association, the Arabidopsis thaliana cytoplasmic enolase mutant, los2, was characterized. These plants were salt sensitive, and there was a specific reduction in enolase abundance in the tonoplast from salt-treated plants. Moreover, tonoplast isolated from mutant plants showed an impaired ability for aldolase stimulation of V-ATPase hydrolytic activity. The association of glycolytic proteins with the tonoplast may not only channel ATP to the V-ATPase, but also directly upregulate H+-pump activity. PMID:20028841

  11. Overexpression of a cotton annexin gene, GhAnn1, enhances drought and salt stress tolerance in transgenic cotton.

    PubMed

    Zhang, Feng; Li, Shufen; Yang, Shuming; Wang, Like; Guo, Wangzhen

    2015-01-01

    Plant annexins are members of a diverse, multigene protein family that has been associated with a variety of cellular processes and responses to abiotic stresses. GhAnn1, which encodes a putative annexin protein, was isolated from a cotton (Gossypium hirsutum L. acc 7235) cDNA library. Tissue-specific expression showed that GhAnn1 is expressed at differential levels in all tissues examined and strongly induced by various phytohormones and abiotic stress. In vivo and in vitro subcellular localization suggested that GhAnn1 is located in the plasma membrane. In response to drought and salt stress, transgenic cotton plants overexpressing GhAnn1 showed significantly higher germination rates, longer roots, and more vigorous growth than wild-type plants. In addition, plants overexpressing GhAnn1 had higher total chlorophyll content, lower lipid peroxidation levels, increased peroxidase activities, and higher levels of proline and soluble sugars, all of which contributed to increased salt and drought stress tolerance. However, transgenic cotton plants in which the expression of GhAnn1 was suppressed showed the opposite results compared to the overexpressing plants. These findings demonstrated that GhAnn1 plays an important role in the abiotic stress response, and that overexpression of GhAnn1 in transgenic cotton improves salt and drought tolerance. PMID:25330941

  12. Function of wheat Ta-UnP gene in enhancing salt tolerance in transgenic Arabidopsis and rice.

    PubMed

    Liang, Wenji; Cui, Weina; Ma, Xiaoli; Wang, Gang; Huang, Zhanjing

    2014-07-18

    Based on microarray analysis results of the salt tolerant wheat mutant, we identified and cloned an unknown salt-induced gene Ta-UnP (Triticum aestivum unknown protein). Quantitative PCR results revealed that Ta-UnP expression was induced not only by salt but also by polyethylene glycol, abscisic acid, and other environmental stress factors. Under salt stress, transgenic Arabidopsis plants that overexpressed Ta-UnP showed superior physiological properties (content of proline, soluble sugar, MDA, and chlorophyll) compared with the control. Subcellular localization demonstrated that Ta-UnP was mainly localized on the cell membrane. The expressions of nine salt tolerance-related genes of Arabidopsis in Ta-UnP-overexpressed Arabidopsis were analyzed via qPCR, and the results revealed that the expressions of SOS2, SOS3, RD29B, and P5CS were significantly up-regulated, whereas the other five genes only slightly changed. The results of the salt tolerance analysis indicated that Ta-UnP can enhance the salt tolerance of transgenic rice plants, and RNAi transgenic rice plants became highly susceptible to salt stress. The results from this study indicate that this novel Ta-UnP may be useful in improving of plant tolerance to salt stress. PMID:24953696

  13. A maize phytochrome-interacting factor 3 improves drought and salt stress tolerance in rice.

    PubMed

    Gao, Yong; Jiang, Wei; Dai, Yi; Xiao, Ning; Zhang, Changquan; Li, Hua; Lu, Yi; Wu, Meiqin; Tao, Xiaoyi; Deng, Dexiang; Chen, Jianmin

    2015-03-01

    Phytochrome-interacting factor 3 (PIF3) activates light-responsive transcriptional network genes in coordination with the circadian clock and plant hormones to modulate plant growth and development. However, little is known of the roles PIF3 plays in the responses to abiotic stresses. In this study, the cloning and functional characterization of the ZmPIF3 gene encoding a maize PIF3 protein is reported. Subcellular localization revealed the presence of ZmPIF3 in the cell nucleus. Expression patterns revealed that ZmPIF3 is expressed strongly in leaves. This expression responds to polyethylene glycol, NaCl stress, and abscisic acid application, but not to cold stress. ZmPIF3 under the control of the ubiquitin promoter was introduced into rice. No difference in growth and development between ZmPIF3 transgenic and wild-type plants was observed under normal growth conditions. However, ZmPIF3 transgenic plants were more tolerant to dehydration and salt stresses. ZmPIF3 transgenic plants had increased relative water content, chlorophyll content, and chlorophyll fluorescence, as well as significantly enhanced cell membrane stability under stress conditions. The over-expression of ZmPIF3 increased the expression of stress-responsive genes, such as Rab16D, DREB2A, OSE2, PP2C, Rab21, BZ8 and P5CS, as detected by real-time PCR analysis. Taken together, these results improve our understanding of the role ZmPIF3 plays in abiotic stresses signaling pathways; our findings also indicate that ZmPIF3 regulates the plant response to drought and salt stresses. PMID:25636202

  14. Basic helix-loop-helix transcription factor from wild rice (OrbHLH2) improves tolerance to salt- and osmotic stress in Arabidopsis.

    PubMed

    Zhou, Jing; Li, Fei; Wang, Jin-Lan; Ma, Yun; Chong, Kang; Xu, Yun-yuan

    2009-08-15

    Salt stress adversely affects plant growth and development. Some plants reduce the damage of high-salt stress by expressing a series of salt-responsive genes. Studies of the molecular mechanism of the salt-stress response have focused on the characterization of components involved in signal perception and transduction. In the present work, we cloned and characterized a basic helix-loop-helix (bHLH) encoding gene, OrbHLH2, from wild rice (Oryza rufipogon), which encodes a homologue protein of ICE1 in Arabidopsis. OrbHLH2 protein localized in the nucleus. Overexpression of OrbHLH2 in Arabidopsis conferred increased tolerance to salt and osmotic stress, and the stress-responsive genes DREB1A/CBF3, RD29A, COR15A and KIN1 were upregulated in transgenic plants. Abscisic acid (ABA) treatment showed a similar effect on the seed germination or transcriptional expression of stress-responsive genes in both wild type and OrbHLH2-overexpressed plants, which implies that OrbHLH2 does not depend on ABA in responding to salt stress. OrbHLH2 may function as a transcription factor and positively regulate salt-stress signals independent of ABA in Arabidopsis, which provides some useful data for improving salt tolerance in crops. PMID:19324458

  15. Potassium Retention under Salt Stress Is Associated with Natural Variation in Salinity Tolerance among Arabidopsis Accessions

    PubMed Central

    Sun, Yanling; Kong, Xiangpei; Li, Cuiling; Liu, Yongxiu; Ding, Zhaojun

    2015-01-01

    Plants are exposed to various environmental stresses during their life cycle such as salt, drought and cold. Natural variation mediated plant growth adaptation has been employed as an effective approach in response to the diverse environmental cues such as salt stress. However, the molecular mechanism underlying this process is not well understood. In the present study, a collection of 82 Arabidopsis thaliana accessions (ecotypes) was screened with a view to identify variation for salinity tolerance. Seven accessions showed a higher level of tolerance than Col-0. The young seedlings of the tolerant accessions demonstrated a higher K+ content and a lower Na+/K+ ratio when exposed to salinity stress, but its Na+ content was the same as that of Col-0. The K+ transporter genes AtHAK5, AtCHX17 and AtKUP1 were up-regulated significantly in almost all the tolerant accessions, even in the absence of salinity stress. There was little genetic variation or positive transcriptional variation between the selections and Col-0 with respect to Na+-related transporter genes, as AtSOS genes, AtNHX1 and AtHKT1;1. In addition, under salinity stress, these selections accumulated higher compatible solutes and lower reactive oxygen species than did Col-0. Taken together, our results showed that natural variation in salinity tolerance of Arabidopsis seems to have been achieved by the strong capacity of K+ retention. PMID:25993093

  16. Proteome profile of salt gland-rich epidermis extracted from a salt-tolerant tree species.

    PubMed

    Tan, Wee-Kee; Ang, Yiqian; Lim, Teck-Kwang; Lim, Tit-Meng; Kumar, Prakash; Loh, Chiang-Shiong; Lin, Qingsong

    2015-10-01

    Preparation of proteins from salt-gland-rich tissues of mangrove plant is necessary for a systematic study of proteins involved in the plant's unique desalination mechanism. Extraction of high-quality proteins from the leaves of mangrove tree species, however, is difficult due to the presence of high levels of endogenous phenolic compounds. In our study, preparation of proteins from only a part of the leaf tissues (i.e. salt gland-rich epidermal layers) was required, rendering extraction even more challenging. By comparing several extraction methods, we developed a reliable procedure for obtaining proteins from salt gland-rich tissues of the mangrove species Avicennia officinalis. Protein extraction was markedly improved using a phenol-based extraction method. Greater resolution 1D protein gel profiles could be obtained. More promising proteome profiles could be obtained through 1D-LC-MS/MS. The number of proteins detected was twice as much as compared to TUTS extraction method. Focusing on proteins that were solely present in each extraction method, phenol-based extracts contained nearly ten times more proteins than those in the extracts without using phenol. The approach could thus be applied for downstream high-throughput proteomic analyses involving LC-MS/MS or equivalent. The proteomics data presented herein are available via ProteomeXchange with identifier PXD001691. PMID:26105009

  17. [Cloning of HAL1 gene and characterization for salt tolerance tomato].

    PubMed

    Zhang, Q; Wang, S F; Zhao, Y X; Zhao, K F; Zhang, H

    2001-11-01

    The HAL1 gene was cloned by PCR strategy and confirmed by sequencing. Its open read frame is 879 bp, encoding a peptide of 294 amino acids (32 kD Protein). A chimaeric construct of HAL1 and Npt II (neomycin phosphotransferase II) was constructed and introduced into commercial cultivars of tomato (Zhong SU No. 5: Lycopersicon escullentum) by Agrobacterium tumefacien-mediated gene transformation. Transformants were selected for their ability to grow and root on media containing kanamycin. Transformation was confirmed by analysis of PCR, Southern blot and RT-PCR. The salt tolerance of transgenic tomato is evaluated by comparing the fresh weight, dry weight, Na+, K+ content of transgenic tomato and control tomato. It is concluded that the over-expressing of HAL1 in tomato could enhance the salt tolerance of the transgenic tomato. PMID:11910760

  18. The Expression of Millettia pinnata Chalcone Isomerase in Saccharomyces cerevisiae Salt-Sensitive Mutants Enhances Salt-Tolerance

    PubMed Central

    Wang, Hui; Hu, Tangjin; Huang, Jianzi; Lu, Xiang; Huang, Baiqu; Zheng, Yizhi

    2013-01-01

    The present study demonstrates a new Millettia pinnata chalcone isomerase (MpCHI) whose transcription level in leaf was confirmed to be enhanced after being treated by seawater or NaCl (500 mM) via transcriptome sequencing and Real-Time Quantitative Reverse Transcription PCR (QRT-PCR) analyses. Its full length cDNA (666 bp) was obtained by 3′-end and 5′-end Rapid Amplification of cDNA Ends (RACE). The analysis via NCBI BLAST indicates that both aminoacid sequence and nucleotide sequence of the MpCHI clone share high homology with other leguminous CHIs (73%–86%). Evolutionarily, the phylogenic analysis further revealed that the MpCHI is a close relative of leguminous CHIs. The MpCHI protein consists of 221 aminoacid (23.64 KDa), whose peptide length, amino acid residues of substrate-binding site and reactive site are very similar to other leguminous CHIs reported previously. Two pYES2-MpCHI transformed salt-sensitive Saccharomyces cerevisiae mutants (Δnha1 and Δnhx1) showed improved salt-tolerance significantly compared to pYES2-vector transformed yeast mutants, suggesting the MpCHI or the flavonoid biosynthesis pathway could regulate the resistance to salt stress in M. pinnata. PMID:23615469

  19. Molecular breeding in Brassica for salt tolerance: importance of microsatellite (SSR) markers for molecular breeding in Brassica

    PubMed Central

    Kumar, Manu; Choi, Ju-Young; Kumari, Nisha; Pareek, Ashwani; Kim, Seong-Ryong

    2015-01-01

    Salinity is one of the important abiotic factors for any crop management in irrigated as well as rainfed areas, which leads to poor harvests. This yield reduction in salt affected soils can be overcome by improving salt tolerance in crops or by soil reclamation. Salty soils can be reclaimed by leaching the salt or by cultivation of salt tolerance crops. Salt tolerance is a quantitative trait controlled by several genes. Poor knowledge about mechanism of its inheritance makes slow progress in its introgression into target crops. Brassica is known to be a good reclamation crop. Inter and intra specific variation within Brassica species shows potential of molecular breeding to raise salinity tolerant genotypes. Among the various molecular markers, SSR markers are getting high attention, since they are randomly sparsed, highly variable and show co-dominant inheritance. Furthermore, as sequencing techniques are improving and softwares to find SSR markers are being developed, SSR markers technology is also evolving rapidly. Comparative SSR marker studies targeting Arabidopsis thaliana and Brassica species which lie in the same family will further aid in studying the salt tolerance related QTLs and subsequent identification of the “candidate genes” and finding out the origin of important QTLs. Although, there are a few reports on molecular breeding for improving salt tolerance using molecular markers in Brassica species, usage of SSR markers has a big potential to improve salt tolerance in Brassica crops. In order to obtain best harvests, role of SSR marker driven breeding approaches play important role and it has been discussed in this review especially for the introgression of salt tolerance traits in crops. PMID:26388887

  20. Molecular breeding in Brassica for salt tolerance: importance of microsatellite (SSR) markers for molecular breeding in Brassica.

    PubMed

    Kumar, Manu; Choi, Ju-Young; Kumari, Nisha; Pareek, Ashwani; Kim, Seong-Ryong

    2015-01-01

    Salinity is one of the important abiotic factors for any crop management in irrigated as well as rainfed areas, which leads to poor harvests. This yield reduction in salt affected soils can be overcome by improving salt tolerance in crops or by soil reclamation. Salty soils can be reclaimed by leaching the salt or by cultivation of salt tolerance crops. Salt tolerance is a quantitative trait controlled by several genes. Poor knowledge about mechanism of its inheritance makes slow progress in its introgression into target crops. Brassica is known to be a good reclamation crop. Inter and intra specific variation within Brassica species shows potential of molecular breeding to raise salinity tolerant genotypes. Among the various molecular markers, SSR markers are getting high attention, since they are randomly sparsed, highly variable and show co-dominant inheritance. Furthermore, as sequencing techniques are improving and softwares to find SSR markers are being developed, SSR markers technology is also evolving rapidly. Comparative SSR marker studies targeting Arabidopsis thaliana and Brassica species which lie in the same family will further aid in studying the salt tolerance related QTLs and subsequent identification of the "candidate genes" and finding out the origin of important QTLs. Although, there are a few reports on molecular breeding for improving salt tolerance using molecular markers in Brassica species, usage of SSR markers has a big potential to improve salt tolerance in Brassica crops. In order to obtain best harvests, role of SSR marker driven breeding approaches play important role and it has been discussed in this review especially for the introgression of salt tolerance traits in crops. PMID:26388887

  1. Genetic regulation of salt stress tolerance revealed by RNA-Seq in cotton diploid wild species, Gossypium davidsonii

    PubMed Central

    Zhang, Feng; Zhu, Guozhong; Du, Lei; Shang, Xiaoguang; Cheng, Chaoze; Yang, Bing; Hu, Yan; Cai, Caiping; Guo, Wangzhen

    2016-01-01

    Cotton is an economically important crop throughout the world, and is a pioneer crop in salt stress tolerance research. Investigation of the genetic regulation of salinity tolerance will provide information for salt stress-resistant breeding. Here, we employed next-generation RNA-Seq technology to elucidate the salt-tolerant mechanisms in cotton using the diploid cotton species Gossypium davidsonii which has superior stress tolerance. A total of 4744 and 5337 differentially expressed genes (DEGs) were found to be involved in salt stress tolerance in roots and leaves, respectively. Gene function annotation elucidated salt overly sensitive (SOS) and reactive oxygen species (ROS) signaling pathways. Furthermore, we found that photosynthesis pathways and metabolism play important roles in ion homeostasis and oxidation balance. Moreover, our studies revealed that alternative splicing also contributes to salt-stress responses at the posttranscriptional level, implying its functional role in response to salinity stress. This study not only provides a valuable resource for understanding the genetic control of salt stress in cotton, but also lays a substantial foundation for the genetic improvement of crop resistance to salt stress. PMID:26838812

  2. The role of antioxidant responses on the tolerance range of extreme halophyte Salsola crassa grown under toxic salt concentrations.

    PubMed

    Yildiztugay, Evren; Ozfidan-Konakci, Ceyda; Kucukoduk, Mustafa

    2014-12-01

    Salsola crassa (Amaranthaceae) is an annual halophytic species and naturally grows in arid soils that are toxic to most plants. In order to study the effects of salinity on their antioxidant system and to determine the tolerance range against salt stress, S. crassa seeds were grown with different concentrations of NaCl (0, 250, 500, 750, 1000, 1250 and 1500mM) for short (15d) and long-term (30d). Results showed that growth (RGR), water content (RWC) and osmotic potential (ΨΠ) decreased and, proline content (Pro) increased at prolonged salt treatment. Unlike K(+) and Ca(2+) contents, S. crassa highly accumulated Na(+) and Cl(-) contents. Chlorophyll fluorescence (Fv/Fm) only decreased in response to 1500mM NaCl at 30d. No salt stimulation of superoxide anion radical (O2(•-)) content was observed in plants treated with the range of 0-500mM NaCl during the experimental period. NaCl increased superoxide dismutase (SOD) activity depending on intensities of Mn-SOD and Fe-SOD isozymes except in 1500mM NaCl-treated plants at 30d. In contrast to catalase (CAT), peroxidase (POX) activity increased throughout the experiment. Also, salinity caused an increase in glutathione reductase (GR) and glutathione peroxidase (GPX) and decreased in ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR) and dehydroascorbate reductase (DHAR) at 15d. Both total ascorbate (tAsA) and glutathione (tGlut) contents significantly increased in treated plants with 1000-1500mM NaCl at 15d. After 0-1000mM NaCl stress, H2O2 and TBARS contents were similar to control groups at 15d, which were consistent with the increased antioxidant activity (POX, GR and GPX). However, H2O2 content was more pronounced at 30d. Therefore, S. crassa exhibited inductions in lipid peroxidation (TBARS content) in response to extreme salt concentrations. These results suggest that S. crassa is tolerant to salt-induced damage at short-term treatments as well as extreme salt concentrations. PMID:25193881

  3. Cold, pH and salt tolerant Penicillium spp. inhabit the high altitude soils in Himalaya, India.

    PubMed

    Dhakar, Kusum; Sharma, Avinash; Pandey, Anita

    2014-04-01

    Twenty five fungal cultures (Penicillium spp.), isolated from soil samples from the high altitudes in the Indian Himalayan region, have been characterized following polyphasic approach. Colony morphology performed on five different media gave varying results; potato dextrose agar being the best for the vegetative growth and sporulation as well. Microscopic observations revealed 18 isolates to be biverticillate and 7 monoverticillate. Based on the phenotypic characters (colony morphology and microscopy), all the isolates were designated to the genus Penicillium. Exposure to low temperature resulted in enhanced sporulation in 23 isolates, while it ceased in case of two. The fungal isolates produced watery exudates in varying amount that in many cases increased at low temperature. All the isolates could grow between 4 and 37 °C, (optimum 24 °C), hence considered psychrotolerant. While all the isolates could tolerate pH from 2 to 14 (optimum 5-9), 7 isolates tolerated pH 1.5 as well. While all the fungal isolates tolerated salt concentration above 10 %; 10 isolates showed tolerance above 20 %. Based on ITS region (ITS1-5.8S-ITS2) analysis the fungal isolates belonged to 25 different species of Penicillium (showing similarity between 95 and 100 %). Characters like tolerance for low temperature, wide range of pH, and high salt concentration, and enhancement in sporulation and production of secondary metabolites such as watery exudates at low temperature can be attributed to the ecological resilience possessed by these fungi for survival under low temperature environment of mountain ecosystem. PMID:24233773

  4. Constitutive overexpression of soybean plasma membrane intrinsic protein GmPIP1;6 confers salt tolerance

    PubMed Central

    2014-01-01

    Background Under saline conditions, plant growth is depressed via osmotic stress and salt can accumulate in leaves leading to further depression of growth due to reduced photosynthesis and gas exchange. Aquaporins are proposed to have a major role in growth of plants via their impact on root water uptake and leaf gas exchange. In this study, soybean plasma membrane intrinsic protein 1;6 (GmPIP1;6) was constitutively overexpressed to evaluate the function of GmPIP1;6 in growth regulation and salt tolerance in soybean. Results GmPIP1;6 is highly expressed in roots as well as reproductive tissues and the protein targeted to the plasma membrane in onion epidermis. Treatment with 100 mM NaCl resulted in reduced expression initially, then after 3 days the expression was increased in root and leaves. The effects of constitutive overexpression of GmPIP1;6 in soybean was examined under normal and salt stress conditions. Overexpression in 2 independent lines resulted in enhanced leaf gas exchange, but not growth under normal conditions compared to wild type (WT). With 100 mM NaCl, net assimilation was much higher in the GmPIP1;6-Oe and growth was enhanced relative to WT. GmPIP1;6-Oe plants did not have higher root hydraulic conductance (Lo) under normal conditions, but were able to maintain Lo under saline conditions compared to WT which decreased Lo. GmPIP1;6-Oe lines grown in the field had increased yield resulting mainly from increased seed size. Conclusions The general impact of overexpression of GmPIP1;6 suggests that it may be a multifunctional aquaporin involved in root water transport, photosynthesis and seed loading. GmPIP1;6 is a valuable gene for genetic engineering to improve soybean yield and salt tolerance. PMID:24998596

  5. Deciphering the salinity adaptation mechanism in Penicilliopsis clavariiformis AP, a rare salt tolerant fungus from mangrove.

    PubMed

    Kashyap, Prem Lal; Rai, Anuradha; Singh, Ruchi; Chakdar, Hillol; Kumar, Sudheer; Srivastava, Alok Kumar

    2016-07-01

    Penicilliopsis clavariiformis AP, a rare salt tolerant fungus reported for the first time from India was identified through polyphasic taxonomy. Scanning electron microscopy showed that the fungus has unique features such as biverticillate penicilli bearing masses of oval to ellipsoidal conidia. The fungus has been characterized for salt tolerance and to understand the relevance of central carbon metabolism in salt stress adaptation. It showed optimal growth at 24 °C and able to tolerate up to 10% (w/v) NaCl. To understand the mechanism of adaptation to high salinity, activities of the key enzymes regulating glycolysis, pentose phosphate pathway, and tricarboxylic acid cycle were investigated under normal (0% NaCl) and saline stress environment (10% NaCl). The results revealed a re-routing of carbon metabolism away from glycolysis to the pentose phosphate pathway (PPP), served as a cellular stress-resistance mechanism in fungi under saline environment. The detection and significant expression of fungus genes (Hsp98, Hsp60, HTB, and RHO) under saline stress suggest that these halotolerance conferring genes from the fungus could have a role in fungus protection and adaptation under saline environment. Overall, the present findings indicate that the rearrangement of the metabolic fluxes distribution and stress related genes play an important role in cell survival and adaptation under saline environment. PMID:26663001

  6. Over-expression of Topoisomerase II Enhances Salt Stress Tolerance in Tobacco

    PubMed Central

    John, Riffat; Ganeshan, Uma; Singh, Badri N.; Kaul, Tanushri; Reddy, Malireddy K.; Sopory, Sudhir K.; Rajam, Manchikatla V.

    2016-01-01

    Topoisomerases are unique enzymes having an ability to remove or add DNA supercoils and untangle the snarled DNA. They can cut, shuffle, and religate DNA strands and remove the torsional stress during DNA replication, transcription or recombination events. In the present study, we over-expressed topoisomerase II (TopoII) in tobacco (Nicotiana tabaccum) and examined its role in growth and development as well as salt (NaCl) stress tolerance. Several putative transgenic plants were generated and the transgene integration and expression was confirmed by PCR and Southern blot analyses, and RT-PCR analysis respectively. Percent seed germination, shoot growth, and chlorophyll content revealed that transgenic lines over-expressing the NtTopoIIα-1 gene exhibited enhanced tolerance to salt (150 and 200 mM NaCl) stress. Moreover, over-expression of TopoII lead to the elevation in proline and glycine betaine levels in response to both concentrations of NaCl as compared to wild-type. In response to NaCl stress, TopoII over-expressing lines showed reduced lipid peroxidation derived malondialdehyde (MDA) generation. These results suggest that TopoII plays a pivotal role in salt stress tolerance in plants.

  7. Iodisation of Salt in Slovenia: Increased Availability of Non-Iodised Salt in the Food Supply

    PubMed Central

    Žmitek, Katja; Pravst, Igor

    2016-01-01

    Salt iodisation is considered a key public health measure for assuring adequate iodine intake in iodine-deficient countries. In Slovenia, the iodisation of all salt was made mandatory in 1953. A considerable regulatory change came in 2003 with the mandatory iodisation of rock and evaporated salt only. In addition, joining the European Union’s free single market in 2004 enabled the import of non-iodised salt. The objective of this study was to investigate the extent of salt iodising in the food supply. We examined both the availability and sale of (non-)iodised salt. Average sales-weighted iodine levels in salt were calculated using the results of a national monitoring of salt quality. Data on the availability and sales of salts were collected in major food retailers in 2014. Iodised salt represented 59.2% of the salt samples, and 95.9% of salt sales, with an average (sales-weighted) level of 24.2 mg KI/kg of salt. The average sales-weighted KI level in non-iodised salts was 3.5 mg KI/kg. We may conclude that the sales-weighted average iodine levels in iodised salt are in line with the regulatory requirements. However, the regulatory changes and the EU single market have considerably affected the availability of non-iodised salt. While sales of non-iodised salt are still low, non-iodised salt represented 33.7% of the salts in our sample. This indicates the existence of a niche market which could pose a risk of inadequate iodine intake in those who deliberately decide to consume non-iodised salt only. Policymakers need to provide efficient salt iodisation intervention to assure sufficient iodine supply in the future. The reported sales-weighting approach enables cost-efficient monitoring of the iodisation of salt in the food supply. PMID:27438852

  8. In-vitro Screening for Salt Tolerance in Hibiscus Species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salinity constitutes a major abiotic stress factor affecting plant growth in many areas of the world, including the U.S. Gulf Coast where extreme weather events such as hurricanes and coastal floodings can periodically increase soil salinity. The objective of this study was to use in vitro meristem ...

  9. Enhanced salt tolerance in tomato plants constitutively expressing heat-shock protein in the endoplasmic reticulum.

    PubMed

    Fu, C; Liu, X X; Yang, W W; Zhao, C M; Liu, J

    2016-01-01

    The accumulation of unfolded or misfolded proteins in the endoplasmic reticulum (ER) causes ER stress and activates the unfolded protein response (UPR) signaling pathway. The UPR signaling pathway is associated with plant responses to adverse environmental conditions. Thus, changes in the UPR signaling pathway might affect plant abiotic tolerance. Here, the role of ER small heat-shock protein (ER-sHSP) in improving plant resistance to salt stress was explored. Under salt stress conditions, ER-sHSP transgenic plants were found to have more vigorous roots, maintain a higher relative water content, absorb less Na(+), accumulate more osmolytes and Ca(2+), and sustain less damage to the photosystem, compared to wild-type non-transgenic plants. Furthermore, we found that the constitutive expression of ER-sHSP under salt stress depressed the expression of other ER molecular chaperones. These results indicate that the constitutive expression of ER-sHSP enhanced salinity tolerance of tomato plants significantly, and alleviated the ER stress caused by the salt stress in plant cells. PMID:27421016

  10. SOS1, a Genetic Locus Essential for Salt Tolerance and Potassium Acquisition.

    PubMed Central

    Wu, S. J.; Ding, L.; Zhu, J. K.

    1996-01-01

    To begin to determine which genes are essential for salt tolerance in higher plants, we identified four salt-hypersensitive mutants of Arabidopsis by using a root-bending assay on NaCl-containing agar plates. These mutants (sos1-1, sos1-2, sos1-3, and sos1-4) are allelic to each other and were caused by single recessive nuclear mutations. The SOS1 gene was mapped to chromosome 2 at 29.5 [plusmn] 6.1 centimorgans. The mutants showed no phenotypic changes except that their growth was >20 times more sensitive to inhibition by NaCl. Salt hypersensitivity is a basic cellular trait exhibited by the mutants at all developmental stages. The sos1 mutants are specifically hypersensitive to Na+ and Li+. The mutants were unable to grow on media containing low levels (below ~1 mM) of potassium. Uptake experiments using 86Rb showed that sos1 mutants are defective in high-affinity potassium uptake. sos1 plants became deficient in potassium when treated with NaCl. The results demonstrate that potassium acquisition is a critical process for salt tolerance in glycophytic plants. PMID:12239394

  11. Genome-wide identification and characterization of Eutrema salsugineum microRNAs for salt tolerance.

    PubMed

    Wu, Ying; Guo, Jing; Cai, Yimei; Gong, Xiaolin; Xiong, Xuemei; Qi, Wenwen; Pang, Qiuying; Wang, Xumin; Wang, Yang

    2016-08-01

    Eutrema salsugineum, a close relative of Arabidopsis thaliana, is a valuable halophytic model plant that has extreme tolerance to salinity. As posttranscriptional gene regulators, microRNAs (miRNAs) control gene expression and a variety of biological processes, including plant-stress responses. To identify salt-stress responsive miRNAs in E. salsugineum and reveal their possible roles in the adaptive response to salt stress, we chose the Solexa sequencing platform to screen the miRNAs in 4-week-old E. salsugineum seedlings under salt treatment. A total of 82 conserved miRNAs belonging to 27 miRNA families and 17 novel miRNAs were identified and 11 conserved miRNA families and 4 novel miRNAs showed a significant response to salt stress. To investigate the possible biological roles of miRNAs, 1060 potential targets were predicted. Moreover, 35 gene ontology (GO) categories and 1 pathway, including a few terms that were directly and indirectly related to salt stress, were significantly enriched in the salt-stress-responsive miRNAs targets. The relative expression analysis of six target genes was analyzed using quantitative real-time polymerase chain reaction (PCR) and showed a negative correlation with their corresponding miRNAs. Many stress regulatory and phytohormone regulatory cis-regulatory elements were widely present in the promoter region of the salt-responsive miRNA precursors. This study describes the large-scale characterization of E. salsugineum miRNAs and provides a useful resource for further understanding of miRNA functions in the regulation of the E. salsugineum salt-stress response. PMID:26806325

  12. Proteomic comparison reveals the contribution of chloroplast to salt tolerance of a wheat introgression line.

    PubMed

    Xu, Wenjing; Lv, Hongjun; Zhao, Mingming; Li, Yongchao; Qi, Yueying; Peng, Zhenying; Xia, Guangmin; Wang, Mengcheng

    2016-01-01

    We previously bred a salt tolerant wheat cv. SR3 with bread wheat cv. JN177 as the parent via asymmetric somatic hybridization, and found that the tolerance is partially attributed to the superior photosynthesis capacity. Here, we compared the proteomes of two cultivars to unravel the basis of superior photosynthesis capacity. In the maps of two dimensional difference gel electrophoresis (2D-DIGE), there were 26 differentially expressed proteins (DEPs), including 18 cultivar-based and 8 stress-responsive ones. 21 of 26 DEPs were identified and classified into four categories, including photosynthesis, photosynthesis system stability, linolenic acid metabolism, and protein synthesis in chloroplast. The chloroplast localization of some DEPs confirmed that the identified DEPs function in the chloroplast. The overexpression of a DEP enhanced salt tolerance in Arabidopsis thaliana. In line with these data, it is concluded that the contribution of chloroplast to high salinity tolerance of wheat cv. SR3 appears to include higher photosynthesis efficiency by promoting system protection and ROS clearance, stronger production of phytohormone JA by enhancing metabolism activity, and modulating the in chloroplast synthesis of proteins. PMID:27562633

  13. Proteomic comparison reveals the contribution of chloroplast to salt tolerance of a wheat introgression line

    PubMed Central

    Xu, Wenjing; Lv, Hongjun; Zhao, Mingming; Li, Yongchao; Qi, Yueying; Peng, Zhenying; Xia, Guangmin; Wang, Mengcheng

    2016-01-01

    We previously bred a salt tolerant wheat cv. SR3 with bread wheat cv. JN177 as the parent via asymmetric somatic hybridization, and found that the tolerance is partially attributed to the superior photosynthesis capacity. Here, we compared the proteomes of two cultivars to unravel the basis of superior photosynthesis capacity. In the maps of two dimensional difference gel electrophoresis (2D-DIGE), there were 26 differentially expressed proteins (DEPs), including 18 cultivar-based and 8 stress-responsive ones. 21 of 26 DEPs were identified and classified into four categories, including photosynthesis, photosynthesis system stability, linolenic acid metabolism, and protein synthesis in chloroplast. The chloroplast localization of some DEPs confirmed that the identified DEPs function in the chloroplast. The overexpression of a DEP enhanced salt tolerance in Arabidopsis thaliana. In line with these data, it is concluded that the contribution of chloroplast to high salinity tolerance of wheat cv. SR3 appears to include higher photosynthesis efficiency by promoting system protection and ROS clearance, stronger production of phytohormone JA by enhancing metabolism activity, and modulating the in chloroplast synthesis of proteins. PMID:27562633

  14. Salinized rivers: degraded systems or new habitats for salt-tolerant faunas?

    PubMed

    Kefford, Ben J; Buchwalter, David; Cañedo-Argüelles, Miguel; Davis, Jenny; Duncan, Richard P; Hoffmann, Ary; Thompson, Ross

    2016-03-01

    Anthropogenic salinization of rivers is an emerging issue of global concern, with significant adverse effects on biodiversity and ecosystem functioning. Impacts of freshwater salinization on biota are strongly mediated by evolutionary history, as this is a major factor determining species physiological salinity tolerance. Freshwater insects dominate most flowing waters, and the common lotic insect orders Ephemeroptera (mayflies), Plecoptera (stoneflies) and Trichoptera (caddisflies) are particularly salt-sensitive. Tolerances of existing taxa, rapid adaption, colonization by novel taxa (from naturally saline environments) and interactions between species will be key drivers of assemblages in saline lotic systems. Here we outline a conceptual framework predicting how communities may change in salinizing rivers. We envision that a relatively small number of taxa will be saline-tolerant and able to colonize salinized rivers (e.g. most naturally saline habitats are lentic; thus potential colonizers would need to adapt to lotic environments), leading to depauperate communities in these environments. PMID:26932680

  15. A cold-adapted, solvent and salt tolerant esterase from marine bacterium Psychrobacter pacificensis.

    PubMed

    Wu, Gaobing; Zhang, Xiangnan; Wei, Lu; Wu, Guojie; Kumar, Ashok; Mao, Tao; Liu, Ziduo

    2015-11-01

    Lipolytic enzymes with unique physico-chemical characteristics are gaining more attention for their immense industrial importance. In this study, a novel lipolytic enzyme (Est11) was cloned from the genomic library of a marine bacterium Psychrobacter pacificensis. The enzyme was expressed in Escherichia coli and purified to homogeneity with molecular mass of 32.9kDa. The recombinant Est11 was able to hydrolyze short chain esters (C2-C8) and displayed an optimum activity against butyrate ester (C4). The optimal temperature and pH were 25°C and 7.5, respectively. Est11 retained more than 70% of its original activity at 10°C, suggesting that it was a cold-active esterase. The enzyme was highly active and stable at high concentration of NaCl (5M). Further, incubation with ethanol, isopropanol, propanediol, DMSO, acetonitrile, and glycerol rendered remarkable positive effects on Est11 activity. Typically, even at the concentration of 30% (v/v), ethanol, DMSO, and propanediol increased Est11 activity by 1.3, 2.0, and 2.4-folds, respectively. This new robust enzyme with remarkable properties like cold-adaptability, exceptional tolerance to salt and organic solvents provides us a promising candidate to meet the needs of some harsh industrial processes. PMID:26231332

  16. An Ethylene-responsive Factor BpERF11 Negatively Modulates Salt and Osmotic Tolerance in Betula platyphylla.

    PubMed

    Zhang, Wenhui; Yang, Guiyan; Mu, Dan; Li, Hongyan; Zang, Dandan; Xu, Hongyun; Zou, Xuezhong; Wang, Yucheng

    2016-01-01

    Ethylene responsive factors (ERFs) play important roles in the abiotic stress; however, only a few ERF genes from woody plants have been functionally characterized. In the present study, an ERF gene from Betula platyphylla (birch), BpERF11, was functionally characterized in response to abiotic stress. BpERF11 is a nuclear protein, which could specifically bind to GCC boxes and DRE motifs. BpERF11-overexpressing and BpERF11 RNA interference (RNAi) knockdown plants were generated for gain- and loss-of-function analysis. BpERF11 negatively regulates resistance to salt and severe osmotic stress, and the transgenic birch plants overexpressing BpERF11 shows increased electrolyte leakage and malondialdehyde (MDA) contents. BpERF11 inhibits the expression of an AtMYB61 homologous gene, resulting in increased stomatal aperture, which elevated the transpiration rate. Furthermore, BpERF11 downregulates the expression of P5CS, SOD and POD genes, but upregulates the expression of PRODH and P5CDH, which results in reduced proline levels and increased reactive oxygen species (ROS) accumulation. BpERF11 also significantly inhibits the expression of LEA and dehydrin genes that involve in abiotic stress tolerance. Therefore, BpERF11 serves as a transcription factor that negatively regulates salt and severe osmotic tolerance by modulating various physiological processes. PMID:26980058

  17. An Ethylene-responsive Factor BpERF11 Negatively Modulates Salt and Osmotic Tolerance in Betula platyphylla

    PubMed Central

    Zhang, Wenhui; Yang, Guiyan; Mu, Dan; Li, Hongyan; Zang, Dandan; Xu, Hongyun; Zou, Xuezhong; Wang, Yucheng

    2016-01-01

    Ethylene responsive factors (ERFs) play important roles in the abiotic stress; however, only a few ERF genes from woody plants have been functionally characterized. In the present study, an ERF gene from Betula platyphylla (birch), BpERF11, was functionally characterized in response to abiotic stress. BpERF11 is a nuclear protein, which could specifically bind to GCC boxes and DRE motifs. BpERF11-overexpressing and BpERF11 RNA interference (RNAi) knockdown plants were generated for gain- and loss-of-function analysis. BpERF11 negatively regulates resistance to salt and severe osmotic stress, and the transgenic birch plants overexpressing BpERF11 shows increased electrolyte leakage and malondialdehyde (MDA) contents. BpERF11 inhibits the expression of an AtMYB61 homologous gene, resulting in increased stomatal aperture, which elevated the transpiration rate. Furthermore, BpERF11 downregulates the expression of P5CS, SOD and POD genes, but upregulates the expression of PRODH and P5CDH, which results in reduced proline levels and increased reactive oxygen species (ROS) accumulation. BpERF11 also significantly inhibits the expression of LEA and dehydrin genes that involve in abiotic stress tolerance. Therefore, BpERF11 serves as a transcription factor that negatively regulates salt and severe osmotic tolerance by modulating various physiological processes. PMID:26980058

  18. Osmoadaptation in rhizobia: ectoine-induced salt tolerance.

    PubMed Central

    Talibart, R; Jebbar, M; Gouesbet, G; Himdi-Kabbab, S; Wróblewski, H; Blanco, C; Bernard, T

    1994-01-01

    After having shown that ectoine (a tetrahydropyrimidine) displays osmoprotective properties towards Escherichia coli (M. Jebbar, R. Talibart, K. Gloux, T. Bernard, and Blanco, J. Bacteriol. 174:5027-5035, 1992), we have investigated the involvement of this molecule in the osmotic adaptation of Rhizobium meliloti. Ectoine appeared almost as effective as glycine betaine in improving the growth of R. meliloti under adverse osmotic conditions (0.5 M NaCl). Moreover, improvement of growth of rhizobial strains insensitive to glycine betaine was also observed. Ectoine transport proved inducible, periplasmic protein dependent, and, as shown by competition experiments, distinct from the transport of glycine betaine. Medium osmolarity had little effect on the uptake characteristics, since the rate of influx increased from 12 to only 20 nmol min-1 mg of protein-1 when NaCl concentrations were raised from 0 to 0.3 or 0.5 M, with a constant of transport of 80 microM. Natural-abundance 13C-nuclear magnetic resonance and radiolabelling assays showed that ectoine, unlike glycine betaine, is not intracellularly accumulated and, as a consequence, does not repress the synthesis of endogenous compatible solutes (glutamate, N-acetylglutaminylglutamine amide, and trehalose). Furthermore, the strong rise in glutamate content in cells osmotically stressed in the presence of ectoine suggests that, instead of being involved in osmotic balance restoration, ectoine should play a key role in triggering the synthesis of endogenous osmolytes. Hence, we believe that there are at least two distinct classes of osmoprotectants: those such as glycine betaine or glutamate, which act as genuine osmolytes, and those such as ectoine, which act as chemical mediators. Images PMID:8071195

  19. How to be moderately halophilic with a broad salt tolerance: Cluesfrom the genome of chromohalobacter salexigens

    SciTech Connect

    Oren, Aharon; Larimer, Frank; Richardson, Paul; Lapidus, Alla; Csonka, Laszlo N.

    2004-07-01

    There are two strategies that enable microorganisms to grow at high salt concentrations. Some groups balance the high osmolality of their environment with high intracellular concentrations of KCl1-4. Adaptation of all intracellular proteins is then necessary, and this is reflected in a large excess of acidic over basic residues and a low content of hydrophobic amino acids 2,5-7. Other halophilic and halotolerant microorganisms keep their intracellular ion concentrations low and synthesize or accumulate organic osmotic solutes 8. While halotolerance enables organisms to colonize highly saline environments,the ecological advantage for a salt-requirement is less obvious. We analyzed the amino acid composition of different categories of proteins of the moderately halophilic bacterium Chromohalobacter salexigens, as deduced from its genome sequence. Comparison with non-halophilic bacteria shows only a slight excess of acidic residues in the cytoplasmic proteins, no significant differences in membrane-bound components, but a distinctive halophilic signature of predicted periplasmic proteins, such as the substrate binding proteins of ABC-type transport systems. The salt requirement of proteins located external to the cytoplasmic membrane may thus determine salt requirement and salt tolerance of prokaryotes.

  20. A comparison of hydroponic and soil-based screening methods to identify salt tolerance in the field in barley

    PubMed Central

    Tavakkoli, Ehsan; Fatehi, Foad; Rengasamy, Pichu; McDonald, Glenn K.

    2012-01-01

    Success in breeding crops for yield and other quantitative traits depends on the use of methods to evaluate genotypes accurately under field conditions. Although many screening criteria have been suggested to distinguish between genotypes for their salt tolerance under controlled environmental conditions, there is a need to test these criteria in the field. In this study, the salt tolerance, ion concentrations, and accumulation of compatible solutes of genotypes of barley with a range of putative salt tolerance were investigated using three growing conditions (hydroponics, soil in pots, and natural saline field). Initially, 60 genotypes of barley were screened for their salt tolerance and uptake of Na+, Cl–, and K+ at 150 mM NaCl and, based on this, a subset of 15 genotypes was selected for testing in pots and in the field. Expression of salt tolerance in saline solution culture was not a reliable indicator of the differences in salt tolerance between barley plants that were evident in saline soil-based comparisons. Significant correlations were observed in the rankings of genotypes on the basis of their grain yield production at a moderately saline field site and their relative shoot growth in pots at ECe 7.2 [Spearman’s rank correlation (rs)=0.79] and ECe 15.3 (rs=0.82) and the crucial parameter of leaf Na+ (rs=0.72) and Cl– (rs=0.82) concentrations at ECe 7.2 dS m−1. This work has established screening procedures that correlated well with grain yield at sites with moderate levels of soil salinity. This study also showed that both salt exclusion and osmotic tolerance are involved in salt tolerance and that the relative importance of these traits may differ with the severity of the salt stress. In soil, ion exclusion tended to be more important at low to moderate levels of stress but osmotic stress became more important at higher stress levels. Salt exclusion coupled with a synthesis of organic solutes were shown to be important components of salt

  1. A comparison of hydroponic and soil-based screening methods to identify salt tolerance in the field in barley.

    PubMed

    Tavakkoli, Ehsan; Fatehi, Foad; Rengasamy, Pichu; McDonald, Glenn K

    2012-06-01

    Success in breeding crops for yield and other quantitative traits depends on the use of methods to evaluate genotypes accurately under field conditions. Although many screening criteria have been suggested to distinguish between genotypes for their salt tolerance under controlled environmental conditions, there is a need to test these criteria in the field. In this study, the salt tolerance, ion concentrations, and accumulation of compatible solutes of genotypes of barley with a range of putative salt tolerance were investigated using three growing conditions (hydroponics, soil in pots, and natural saline field). Initially, 60 genotypes of barley were screened for their salt tolerance and uptake of Na(+), Cl(-), and K(+) at 150 mM NaCl and, based on this, a subset of 15 genotypes was selected for testing in pots and in the field. Expression of salt tolerance in saline solution culture was not a reliable indicator of the differences in salt tolerance between barley plants that were evident in saline soil-based comparisons. Significant correlations were observed in the rankings of genotypes on the basis of their grain yield production at a moderately saline field site and their relative shoot growth in pots at EC(e) 7.2 [Spearman's rank correlation (rs)=0.79] and EC(e) 15.3 (rs=0.82) and the crucial parameter of leaf Na(+) (rs=0.72) and Cl(-) (rs=0.82) concentrations at EC(e) 7.2 dS m(-1). This work has established screening procedures that correlated well with grain yield at sites with moderate levels of soil salinity. This study also showed that both salt exclusion and osmotic tolerance are involved in salt tolerance and that the relative importance of these traits may differ with the severity of the salt stress. In soil, ion exclusion tended to be more important at low to moderate levels of stress but osmotic stress became more important at higher stress levels. Salt exclusion coupled with a synthesis of organic solutes were shown to be important components of

  2. Structural and functional analysis of transmembrane segment IV of the salt tolerance protein Sod2.

    PubMed

    Ullah, Asad; Kemp, Grant; Lee, Brian; Alves, Claudia; Young, Howard; Sykes, Brian D; Fliegel, Larry

    2013-08-23

    Sod2 is the plasma membrane Na(+)/H(+) exchanger of the fission yeast Schizosaccharomyces pombe. It provides salt tolerance by removing excess intracellular sodium (or lithium) in exchange for protons. We examined the role of amino acid residues of transmembrane segment IV (TM IV) ((126)FPQINFLGSLLIAGCITSTDPVLSALI(152)) in activity by using alanine scanning mutagenesis and examining salt tolerance in sod2-deficient S. pombe. Two amino acids were critical for function. Mutations T144A and V147A resulted in defective proteins that did not confer salt tolerance when reintroduced into S. pombe. Sod2 protein with other alanine mutations in TM IV had little or no effect. T144D and T144K mutant proteins were inactive; however, a T144S protein was functional and provided lithium, but not sodium, tolerance and transport. Analysis of sensitivity to trypsin indicated that the mutations caused a conformational change in the Sod2 protein. We expressed and purified TM IV (amino acids 125-154). NMR analysis yielded a model with two helical regions (amino acids 128-142 and 147-154) separated by an unwound region (amino acids 143-146). Molecular modeling of the entire Sod2 protein suggested that TM IV has a structure similar to that deduced by NMR analysis and an overall structure similar to that of Escherichia coli NhaA. TM IV of Sod2 has similarities to TM V of the Zygosaccharomyces rouxii Na(+)/H(+) exchanger and TM VI of isoform 1 of mammalian Na(+)/H(+) exchanger. TM IV of Sod2 is critical to transport and may be involved in cation binding or conformational changes of the protein. PMID:23836910

  3. Heterologous Overexpression of Poplar SnRK2 Genes Enhanced Salt Stress Tolerance in Arabidopsis thaliana

    PubMed Central

    Song, Xueqing; Yu, Xiang; Hori, Chiaki; Demura, Taku; Ohtani, Misato; Zhuge, Qiang

    2016-01-01

    Subfamily 2 of SNF1-related protein kinase (SnRK2) plays important roles in plant abiotic stress responses as a global positive regulator of abscisic acid signaling. In the genome of the model tree Populus trichocarpa, 12 SnRK2 genes have been identified, and some are upregulated by abiotic stresses. In this study, we heterologously overexpressed the PtSnRK2 genes in Arabidopsis thaliana and found that overexpression of PtSnRK2.5 and PtSnRK2.7 genes enhanced stress tolerance. In the PtSnRK2.5 and PtSnRK2.7 overexpressors, chlorophyll content, and root elongation were maintained under salt stress conditions, leading to higher survival rates under salt stress compared with those in the wild type. Transcriptomic analysis revealed that PtSnRK2.7 overexpression affected stress-related metabolic genes, including lipid metabolism and flavonoid metabolism, even under normal growth conditions. However, the stress response genes reported to be upregulated in Arabidopsis SRK2C/SnRK2.6 and wheat SnRK2.8 overexpressors were not changed by PtSnRK2.7 overexpression. Furthermore, PtSnRK2.7 overexpression widely and largely influenced the transcriptome in response to salt stress; genes related to transport activity, including anion transport-related genes, were characteristically upregulated, and a variety of metabolic genes were specifically downregulated. We also found that the salt stress response genes were greatly upregulated in the PtSnRK2.7 overexpressor. Taken together, poplar subclass 2 PtSnRK2 genes can modulate salt stress tolerance in Arabidopsis, through the activation of cellular signaling pathways in a different manner from that by herbal subclass 2 SnRK2 genes. PMID:27242819

  4. Polyamines Confer Salt Tolerance in Mung Bean (Vigna radiata L.) by Reducing Sodium Uptake, Improving Nutrient Homeostasis, Antioxidant Defense, and Methylglyoxal Detoxification Systems

    PubMed Central

    Nahar, Kamrun; Hasanuzzaman, Mirza; Rahman, Anisur; Alam, Md. Mahabub; Mahmud, Jubayer-Al; Suzuki, Toshisada; Fujita, Masayuki

    2016-01-01

    The physiological roles of PAs (putrescine, spermidine, and spermine) were investigated for their ability to confer salt tolerance (200 mM NaCl, 48 h) in mung bean seedlings (Vigna radiata L. cv. BARI Mung-2). Salt stress resulted in Na toxicity, decreased K, Ca, Mg, and Zn contents in roots and shoots, and disrupted antioxidant defense system which caused oxidative damage as indicated by increased lipid peroxidation, H2O2 content, O2•- generation rate, and lipoxygenase activity. Salinity-induced methylglyoxal (MG) toxicity was also clearly evident. Salinity decreased leaf chlorophyll (chl) and relative water content (RWC). Supplementation of salt affected seedlings with exogenous PAs enhanced the contents of glutathione and ascorbate, increased activities of antioxidant enzymes (dehydroascorbate reductase, glutathione reductase, catalase, and glutathione peroxidase) and glyoxalase enzyme (glyoxalase II), which reduced salt-induced oxidative stress and MG toxicity, respectively. Exogenous PAs reduced cellular Na content and maintained nutrient homeostasis and modulated endogenous PAs levels in salt affected mung bean seedlings. The overall salt tolerance was reflected through improved tissue water and chl content, and better seedling growth. PMID:27516763

  5. Polyamines Confer Salt Tolerance in Mung Bean (Vigna radiata L.) by Reducing Sodium Uptake, Improving Nutrient Homeostasis, Antioxidant Defense, and Methylglyoxal Detoxification Systems.

    PubMed

    Nahar, Kamrun; Hasanuzzaman, Mirza; Rahman, Anisur; Alam, Md Mahabub; Mahmud, Jubayer-Al; Suzuki, Toshisada; Fujita, Masayuki

    2016-01-01

    The physiological roles of PAs (putrescine, spermidine, and spermine) were investigated for their ability to confer salt tolerance (200 mM NaCl, 48 h) in mung bean seedlings (Vigna radiata L. cv. BARI Mung-2). Salt stress resulted in Na toxicity, decreased K, Ca, Mg, and Zn contents in roots and shoots, and disrupted antioxidant defense system which caused oxidative damage as indicated by increased lipid peroxidation, H2O2 content, [Formula: see text] generation rate, and lipoxygenase activity. Salinity-induced methylglyoxal (MG) toxicity was also clearly evident. Salinity decreased leaf chlorophyll (chl) and relative water content (RWC). Supplementation of salt affected seedlings with exogenous PAs enhanced the contents of glutathione and ascorbate, increased activities of antioxidant enzymes (dehydroascorbate reductase, glutathione reductase, catalase, and glutathione peroxidase) and glyoxalase enzyme (glyoxalase II), which reduced salt-induced oxidative stress and MG toxicity, respectively. Exogenous PAs reduced cellular Na content and maintained nutrient homeostasis and modulated endogenous PAs levels in salt affected mung bean seedlings. The overall salt tolerance was reflected through improved tissue water and chl content, and better seedling growth. PMID:27516763

  6. Allantoin accumulation mediated by allantoinase downregulation and transport by Ureide Permease 5 confers salt stress tolerance to Arabidopsis plants.

    PubMed

    Lescano, Carlos Ignacio; Martini, Carolina; González, Claudio Alejandro; Desimone, Marcelo

    2016-07-01

    Allantoin, a metabolite generated in the purine degradation pathway, was primarily considered an intermediate for recycling of the abundant nitrogen assimilated in plant purines. More specifically, tropical legumes utilize allantoin and allantoic acid as major nodule-to-shoot nitrogen transport compounds. In other species, an increase in allantoin content was observed under different stress conditions, but the underlying molecular mechanisms remain poorly understood. In this work, Arabidopsis thaliana was used as a model system to investigate the effects of salt stress on allantoin metabolism and to know whether its accumulation results in plant protection. Plant seedlings treated with NaCl at different concentrations showed higher allantoin and lower allantoic acid contents. Treatments with NaCl favored the expression of genes involved in allantoin synthesis, but strongly repressed the unique gene encoding allantoinase (AtALN). Due to the potential regulatory role of this gene for allantoin accumulation, AtALN promoter activity was studied using a reporter system. GUS mediated coloration was found in specific plant tissues and was diminished with increasing salt concentrations. Phenotypic analysis of knockout, knockdown and stress-inducible mutants for AtALN revealed that allantoin accumulation is essential for salt stress tolerance. In addition, the possible role of allantoin transport was investigated. The Ureide Permease 5 (UPS5) is expressed in the cortex and endodermis of roots and its transcription is enhanced by salt treatment. Ups5 knockout plants under salt stress presented a susceptible phenotype and altered allantoin root-to-shoot content ratios. Possible roles of allantoin as a protectant compound in oxidative events or signaling are discussed. PMID:27209043

  7. Hydrophobic interaction chromatography in dual salt system increases protein binding capacity.

    PubMed

    Senczuk, Anna M; Klinke, Ralph; Arakawa, Tsutomu; Vedantham, Ganesh; Yigzaw, Yinges

    2009-08-01

    Hydrophobic interaction chromatography (HIC) uses weakly hydrophobic resins and requires a salting-out salt to promote protein-resin interaction. The salting-out effects increase with protein and salt concentration. Dynamic binding capacity (DBC) is dependent on the binding constant, as well as on the flow characteristics during sample loading. DBC increases with the salt concentration but decreases with increasing flow rate. Dynamic and operational binding capacity have a major raw material cost/processing time impact on commercial scale production of monoclonal antibodies. In order to maximize DBC the highest salt concentration without causing precipitation is used. We report here a novel method to maintain protein solubility while increasing the DBC by using a combination of two salting-out salts (referred to as dual salt). In a series of experiments, we explored the dynamic capacity of a HIC resin (TosoBioscience Butyl 650M) with combinations of salts. Using a model antibody, we developed a system allowing us to increase the dynamic capacity up to twofold using the dual salt system over traditional, single salt system. We also investigated the application of this novel approach to several other proteins and salt combinations, and noted a similar protein solubility and DBC increase. The observed increase in DBC in the dual salt system was maintained at different linear flow rates and did not impact selectivity. PMID:19382248

  8. Salt Stress in Thellungiella halophila Activates Na+ Transport Mechanisms Required for Salinity Tolerance1

    PubMed Central

    Vera-Estrella, Rosario; Barkla, Bronwyn J.; García-Ramírez, Liliana; Pantoja, Omar

    2005-01-01

    Salinity is considered one of the major limiting factors for plant growth and agricultural productivity. We are using salt cress (Thellungiella halophila) to identify biochemical mechanisms that enable plants to grow in saline conditions. Under salt stress, the major site of Na+ accumulation occurred in old leaves, followed by young leaves and taproots, with the least accumulation occurring in lateral roots. Salt treatment increased both the H+ transport and hydrolytic activity of salt cress tonoplast (TP) and plasma membrane (PM) H+-ATPases from leaves and roots. TP Na+/H+ exchange was greatly stimulated by growth of the plants in NaCl, both in leaves and roots. Expression of the PM H+-ATPase isoform AHA3, the Na+ transporter HKT1, and the Na+/H+ exchanger SOS1 were examined in PMs isolated from control and salt-treated salt cress roots and leaves. An increased expression of SOS1, but no changes in levels of AHA3 and HKT1, was observed. NHX1 was only detected in PM fractions of roots, and a salt-induced increase in protein expression was observed. Analysis of the levels of expression of vacuolar H+-translocating ATPase subunits showed no major changes in protein expression of subunits VHA-A or VHA-B with salt treatment; however, VHA-E showed an increased expression in leaf tissue, but not in roots, when the plants were treated with NaCl. Salt cress plants were able to distribute and store Na+ by a very strict control of ion movement across both the TP and PM. PMID:16244148

  9. Salt tolerant Methylobacterium mesophilicum showed viable colonization abilities in the plant rhizosphere.

    PubMed

    Egamberdieva, Dilfuza; Wirth, Stephan; Alqarawi, Abdulaziz A; Abd Allah, E F

    2015-09-01

    The source of infection has always been considered as an important factor in epidemiology and mostly linked to environmental source such as surface water, soil, plants and also animals. The activity of the opportunistic pathogens associated with plant root, their adaptation and survival under hostile environmental condition is poorly understood. In this study the salt tolerance ability of Methylobacterium mesophilicum and its colonization in the root and shoot of plants under severe drought and salt stress conditions were investigated. The colonization of plant by M. mesophilicum was investigated in a gnotobiotic sand system, and their survival in pots with saline soil. Bacterial strain was found to colonize rhizosphere of cucumber, tomato and paprika grown under normal and salt stress condition and reached up to 6.4 × 10(4) and 2.6 × 10(4) CFU/g root. The strain was resistant to Gentamicin, Ampicillin, Amoxicillin plus Clavulanic acid, Cefotaxime, neomycin, penicillin and was also tolerant to salinity stress (up to 6% NaCl). These abilities play important roles in enabling persistent colonization of the plant surface by M. mesophilicum strains. In conclusion, this study provides background information on the behaviour of opportunistic pathogen M. mesophilicum on plants and their survival in harsh environmental conditions. PMID:26288563

  10. Polyamine transporters and polyamines increase furfural tolerance during xylose fermentation with ethanologenic Escherichia coli strain LY180.

    PubMed

    Geddes, Ryan D; Wang, Xuan; Yomano, Lorraine P; Miller, Elliot N; Zheng, Huabao; Shanmugam, Keelnatham T; Ingram, Lonnie O

    2014-10-01

    Expression of genes encoding polyamine transporters from plasmids and polyamine supplements increased furfural tolerance (growth and ethanol production) in ethanologenic Escherichia coli LY180 (in AM1 mineral salts medium containing xylose). This represents a new approach to increase furfural tolerance and may be useful for other organisms. Microarray comparisons of two furfural-resistant mutants (EMFR9 and EMFR35) provided initial evidence for the importance of polyamine transporters. Each mutant contained a single polyamine transporter gene that was upregulated over 100-fold (microarrays) compared to that in the parent LY180, as well as a mutation that silenced the expression of yqhD. Based on these genetic changes, furfural tolerance was substantially reconstructed in the parent, LY180. Deletion of potE in EMFR9 lowered furfural tolerance to that of the parent. Deletion of potE and puuP in LY180 also decreased furfural tolerance, indicating functional importance of the native genes. Of the 8 polyamine transporters (18 genes) cloned and tested, half were beneficial for furfural tolerance (PotE, PuuP, PlaP, and PotABCD). Supplementing AM1 mineral salts medium with individual polyamines (agmatine, putrescine, and cadaverine) also increased furfural tolerance but to a smaller extent. In pH-controlled fermentations, polyamine transporter plasmids were shown to promote the metabolism of furfural and substantially reduce the time required to complete xylose fermentation. This increase in furfural tolerance is proposed to result from polyamine binding to negatively charged cellular constituents such as nucleic acids and phospholipids, providing protection from damage by furfural. PMID:25063650