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Sample records for acquired salt tolerance

  1. 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

  2. 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.

  3. Tobacco plants over-expressing the sweet orange tau glutathione transferases (CsGSTUs) acquire tolerance to the diphenyl ether herbicide fluorodifen and to salt and drought stresses.

    PubMed

    Lo Cicero, Luca; Madesis, Panagiotis; Tsaftaris, Athanasios; Lo Piero, Angela Roberta

    2015-08-01

    The glutathione transferases (GSTs) are members of a superfamily of enzymes with pivotal role in the detoxification of both xenobiotic and endogenous compounds. In this work, the generation and characterization of transgenic tobacco plants over-expressing tau glutathione transferases from Citrus sinensis (CsGSTU1 and CsGSTU2) and several cross-mutate forms of these genes are reported. Putative transformed plants were verified for the presence of the transgenes and the relative quantification of transgene copy number was evaluated by Taqman real time PCR. The analysis of gene expression revealed that transformed plants exhibit high levels of CsGSTU transcription suggesting that the insertion of the transgenes occurred in transcriptional active regions of the tobacco genome. In planta studies demonstrate that transformed tobacco plants gain tolerance against fluorodifen. Simultaneously, the wild type CsGSTU genes were in vitro expressed and their kinetic properties were determined using fluorodifen as substrate. The results show that CsGSTU2 follows a Michaelis-Menten hyperbolic kinetic, whereas CsGSTU1 generates a sigmoid plot typical of the regulatory enzymes, thus suggesting that when working at sub-lethal fluorodifen concentrations CsGSTU2 can counteract the herbicide injury more efficiently than the CsGSTU1. Moreover, the transgenic tobacco plant over-expressing CsGSTs exhibited both drought and salinity stress tolerance. However, as we show that CsGSTUs do not function as glutathione peroxidase in vitro, the protective effect against salt and drought stress is not due to a direct scavenging activity of the oxidative stress byproducts. The transgenic tobacco plants, which are described in the present study, can be helpful for phytoremediation of residual xenobiotics in the environment and overall the over-expression of CsGSTUs can be helpful to develop genetically modified crops with high resistance to abiotic stresses. PMID:25819876

  4. 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

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. 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

  10. 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.

  11. Exosomes: The missing link between microchimerism and acquired tolerance?

    PubMed

    Burlingham, William J

    2014-01-01

    It has become increasingly clear that the immune system of viviparous mammals is much more in the business of acquiring tolerance to non-self antigens, than it is in rejecting cells that express them (for a recent review, highlighting the role of Treg cells, see ref. (1) ). It is also clear that both self-tolerance, and acquired tolerance to non-self is a dynamic process, with a natural ebb and flow. As has been often said of an effective team defense in sports, tolerance will "bend but does not break." How microchimerism, defined as the presence of extremely rare [1/10(4)-1/10(6)] cells of a genetically different individual, can induce either new immunogenetic pressures that push self-tolerance to the breaking point, or alternatively, provide relief from pre-existing immunogenetic risk, preventing development of autoimmune disease, remains a mystery. Indeed, the inability to directly correlate DNA-level microchimerism detected in blood samples by qPCR, with naturally occurring regulation to minor H and MHC alloantigens expressed by the rare cells themselves, has been frustrating to researchers in this field. (2) [Haynes, W.J. et al, this issue] However, recent developments in the areas of transplantation and reproductive immunology offer clues to how the effects of microchimerism can be amplified, and how a disproportionate immune impact might occur from a very limited cell source. PMID:26679558

  12. 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

  13. 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

  14. 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...

  15. 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.

  16. 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...

  17. 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...

  18. (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.

  19. 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

  20. 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

  1. 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.

  2. 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.

  3. 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

  4. 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

  5. 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...

  6. 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,......

  7. 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.

  8. 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

  9. 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

  10. 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

  11. 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.

  12. 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

  13. Transformation of Synechococcus with a gene for choline oxidase enhances tolerance to salt stress.

    PubMed

    Deshnium, P; Los, D A; Hayashi, H; Mustardy, L; Murata, N

    1995-12-01

    Choline oxidase, isolated from the soil bacterium Arthrobacter globiformis, converts choline to glycinebetaine (N-trimethylglycine) without a requirement for any cofactors. The gene for this enzyme, designated codA, was cloned and introduced into the cyanobacterium Synechococcus sp. PCC 7942. The codA gene was expressed under the control of a strong constitutive promoter, and the transformed cells accumulated glycinebetaine at intracellular levels of 60-80 mM. Consequently the cells acquired tolerance to salt stress, as evaluated in terms of growth, accumulation of chlorophyll and photosynthetic activity. PMID:8555454

  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. 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

  16. 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

  17. 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.

  18. 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.

  19. Acquired tolerance to dilator action of hydrallazine during oral administration.

    PubMed Central

    Robinson, B F; Collier, J G; Dobbs, R J

    1980-01-01

    1 The effect on forearm blood flow of local intra-arterial infusion of hydrallazine has been studied in twelve patients with essential hypertension and six normal subjects. 2 When the patients with hypertension were not taking hydrallazine by mouth, they responded to intra-arterial infusions with a dose-dependent increase in forearm blood flow that was not significantly different from that in normal subjects. 3 When the patients were taking hydrallazine by mouth, the increase in forearm flow in response to intra-arterial infusions was reduced and forearm vascular resistance did not fall as low as it did in the control study (P less than 0.01). 4 In four patients, the response to intra-arterial hydrallazine was attenuated to a major extent, and in three of these, there was little or no response to oral treatment. In eight patients, the response to intra-arterial hydrallazine did not fall below one half of that in the control study and this minor reduction in sensitivity might be expected to impair, but not abolish, the response to oral treatment. 5 It is concluded that the resistance vessels commonly develop tolerance to the dilator action of hydrallazine during long-term oral therapy. In some patients a high degree of tolerance develops and this is an important cause of failure to respond to oral treatment. PMID:6769454

  20. 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...

  1. 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...

  2. 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.

  3. 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

  4. 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

  5. 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. ...

  6. 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

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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

  16. 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

  17. 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

  18. 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

  19. 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

  20. 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

  1. 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.

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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,...

  7. 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,...

  8. 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,...

  9. 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

  10. 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...

  11. 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

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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

  18. 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

  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. 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

  1. 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

  2. Molecular Characterization of Acquired Tolerance of Tumor Cells to Picropodophyllin (PPP)

    PubMed Central

    Hashemi, Jamileh; Worrall, Claire; Vasilcanu, Daiana; Fryknäs, Mårten; Sulaiman, Luqman; Karimi, Mohsen; Weng, Wen-Hui; Lui, Weng-Onn; Rudduck, Christina; Axelson, Magnus; Jernberg-Wiklund, Helena; Girnita, Leonard; Larsson, Olle; Larsson, Catharina

    2011-01-01

    Background Picropodophyllin (PPP) is a promising novel anti-neoplastic agent that efficiently kills tumor cells in vitro and causes tumor regression and increased survival in vivo. We have previously reported that PPP treatment induced moderate tolerance in two out of 10 cell lines only, and here report the acquired genomic and expression alterations associated with PPP selection over 1.5 years of treatment. Methodology/Principal Findings Copy number alterations monitored using metaphase and array-based comparative genomic hybridization analyses revealed largely overlapping alterations in parental and maximally tolerant cells. Gain/ amplification of the MYC and PVT1 loci in 8q24.21 were verified on the chromosome level. Abnormalities observed in connection to PPP treatment included regular gains and losses, as well as homozygous losses in 10q24.1-q24.2 and 12p12.3-p13.2 in one of the lines and amplification at 5q11.2 in the other. Abnormalities observed in both tolerant derivatives include amplification/gain of 5q11.2, gain of 11q12.1-q14.3 and gain of 13q33.3-qter. Using Nexus software analysis we combined the array-CGH data with data from gene expression profilings and identified genes that were altered in both inputs. A subset of genes identified as downregulated (ALDH1A3, ANXA1, TLR4 and RAB5A) or upregulated (COX6A1, NFIX, ME1, MAPK and TAP2) were validated by siRNA in the tolerant or parental cells to alter sensitivity to PPP and confirmed to alter sensitivity to PPP in further cell lines. Conclusions Long-term PPP selection lead to altered gene expression in PPP tolerant cells with increase as well as decrease of genes involved in cell death such as PTEN and BCL2. In addition, acquired genomic copy number alterations were observed that were often reflected by altered mRNA expression levels for genes in the same regions. PMID:21423728

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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

  16. 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

  17. 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

  18. 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...

  19. A Single Amino-Acid Substitution in the Sodium Transporter HKT1 Associated with Plant Salt Tolerance.

    PubMed

    Ali, Akhtar; Raddatz, Natalia; Aman, Rashid; Kim, Songmi; Park, Hyeong Cheol; Jan, Masood; Baek, Dongwon; Khan, Irfan Ullah; Oh, Dong-Ha; Lee, Sang Yeol; Bressan, Ray A; Lee, Keun Woo; Maggio, Albino; Pardo, Jose M; Bohnert, Hans J; Yun, Dae-Jin

    2016-07-01

    A crucial prerequisite for plant growth and survival is the maintenance of potassium uptake, especially when high sodium surrounds the root zone. The Arabidopsis HIGH-AFFINITY K(+) TRANSPORTER1 (HKT1), and its homologs in other salt-sensitive dicots, contributes to salinity tolerance by removing Na(+) from the transpiration stream. However, TsHKT1;2, one of three HKT1 copies in Thellungiella salsuginea, a halophytic Arabidopsis relative, acts as a K(+) transporter in the presence of Na(+) in yeast (Saccharomyces cerevisiae). Amino-acid sequence comparisons indicated differences between TsHKT1;2 and most other published HKT1 sequences with respect to an Asp residue (D207) in the second pore-loop domain. Two additional T salsuginea and most other HKT1 sequences contain Asn (n) in this position. Wild-type TsHKT1;2 and altered AtHKT1 (AtHKT1(N-D)) complemented K(+)-uptake deficiency of yeast cells. Mutant hkt1-1 plants complemented with both AtHKT1(N) (-) (D) and TsHKT1;2 showed higher tolerance to salt stress than lines complemented by the wild-type AtHKT1 Electrophysiological analysis in Xenopus laevis oocytes confirmed the functional properties of these transporters and the differential selectivity for Na(+) and K(+) based on the n/d variance in the pore region. This change also dictated inward-rectification for Na(+) transport. Thus, the introduction of Asp, replacing Asn, in HKT1-type transporters established altered cation selectivity and uptake dynamics. We describe one way, based on a single change in a crucial protein that enabled some crucifer species to acquire improved salt tolerance, which over evolutionary time may have resulted in further changes that ultimately facilitated colonization of saline habitats. PMID:27208305

  20. A Single Amino-Acid Substitution in the Sodium Transporter HKT1 Associated with Plant Salt Tolerance1[OPEN

    PubMed Central

    Ali, Akhtar; Aman, Rashid; Park, Hyeong Cheol; Jan, Masood; Baek, Dongwon; Khan, Irfan Ullah; Oh, Dong-Ha; Lee, Sang Yeol; Bressan, Ray A.; Lee, Keun Woo; Maggio, Albino; Yun, Dae-Jin

    2016-01-01

    A crucial prerequisite for plant growth and survival is the maintenance of potassium uptake, especially when high sodium surrounds the root zone. The Arabidopsis HIGH-AFFINITY K+ TRANSPORTER1 (HKT1), and its homologs in other salt-sensitive dicots, contributes to salinity tolerance by removing Na+ from the transpiration stream. However, TsHKT1;2, one of three HKT1 copies in Thellungiella salsuginea, a halophytic Arabidopsis relative, acts as a K+ transporter in the presence of Na+ in yeast (Saccharomyces cerevisiae). Amino-acid sequence comparisons indicated differences between TsHKT1;2 and most other published HKT1 sequences with respect to an Asp residue (D207) in the second pore-loop domain. Two additional T. salsuginea and most other HKT1 sequences contain Asn (n) in this position. Wild-type TsHKT1;2 and altered AtHKT1 (AtHKT1N-D) complemented K+-uptake deficiency of yeast cells. Mutant hkt1-1 plants complemented with both AtHKT1N-D and TsHKT1;2 showed higher tolerance to salt stress than lines complemented by the wild-type AtHKT1. Electrophysiological analysis in Xenopus laevis oocytes confirmed the functional properties of these transporters and the differential selectivity for Na+ and K+ based on the n/d variance in the pore region. This change also dictated inward-rectification for Na+ transport. Thus, the introduction of Asp, replacing Asn, in HKT1-type transporters established altered cation selectivity and uptake dynamics. We describe one way, based on a single change in a crucial protein that enabled some crucifer species to acquire improved salt tolerance, which over evolutionary time may have resulted in further changes that ultimately facilitated colonization of saline habitats. PMID:27208305

  1. 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

  2. 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

  3. 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

  4. 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

  5. [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

  6. 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

  7. 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...

  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. 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.

  12. 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

  13. 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

  14. Inducible lymphoid clusters, iSALTs, in contact dermatitis: a new concept of acquired cutaneous immune responses.

    PubMed

    Natsuaki, Yohei; Kabashima, Kenji

    2016-09-01

    Antigen presentation to peripheral memory T cells is a key step in the prompt elicitation of acquired immune responses. In the mucosa, specific sentinel lymphoid tissues called mucosa-associated lymphoid tissue serve as antigen presentation sites. Correspondingly, the concept of skin-associated lymphoid tissue (SALT) has been proposed in the 1980s. However, the details of SALT have not been clarified so far. Recently, the live imaging analysis using two photon microscopes are developed. Here, we have identified inducible lymphoid clusters in the skin, we called it inducible SALTs (iSALTs), using a murine contact hypersensitivity model. In the elicitation phase, dendritic cells (DCs) formed clusters and interacted for several hours with effector memory T cells in the dermis. This interaction was essential for proliferation and activation of effector memory T cells in situ in an antigen dependent manner. Interestingly, DC clusters were abrogated by depletion of skin macrophages. Furthermore, IL-1 treatment induced CXCL2 production from macrophages and DC clusters were suppressed with the blockade of IL-1R or CXCR2. Taken together, this sustained conjugation between DCs and memory T cells, iSALTs, is essential for establishment of the effector phase in acquired cutaneous immunity. PMID:26941109

  15. 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

  16. 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

  17. 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

  18. (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

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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.

  6. 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

  7. 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

  8. 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

  9. Acquired Tolerance to Ivermectin and Moxidectin after Drug Selection Pressure in the Nematode Caenorhabditis elegans.

    PubMed

    Ménez, Cécile; Alberich, Mélanie; Kansoh, Dalia; Blanchard, Alexandra; Lespine, Anne

    2016-08-01

    Ivermectin and moxidectin are the most widely administered anthelmintic macrocyclic lactones (MLs) to treat human and animal nematode infections. Their widespread and frequent use has led to a high level of resistance to these drugs. Although they have the same mode of action, differences in terms of selection for drug resistance have been reported. Our objective was to study and compare changes occurring upon ivermectin or moxidectin selection in the model nematode Caenorhabditis elegans C. elegans worms were submitted to stepwise exposure to increasing doses of moxidectin. The sensitivity of moxidectin-selected worms to MLs was determined in a larval development assay and compared with those of wild-type and ivermectin-selected strains. Selection with either ivermectin or moxidectin led to acquired tolerance to ivermectin, moxidectin, and eprinomectin. Importantly, moxidectin was the most potent ML in both ivermectin- and moxidectin-selected strains. Interestingly, this order of potency was also observed in a resistant Haemonchus contortus isolate. In addition, ivermectin- and moxidectin-selected strains displayed constitutive overexpression of several genes involved in xenobiotic metabolism and transport. Moreover, verapamil potentiated sensitivity to ivermectin and moxidectin, demonstrating that ABC transporters play a role in ML sensitivity in ML-selected C. elegans strains. Finally, both ivermectin- and moxidectin-selected strains displayed a dye-filling-defective phenotype. Overall, this work demonstrated that selection with ivermectin or moxidectin led to cross-resistance to several MLs in nematodes and that the induction of detoxification systems and defects in the integrity of amphidial neurons are two mechanisms that appear to affect the responsiveness of worms to both ivermectin and moxidectin. PMID:27246778

  10. 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

  11. 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

  12. [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

  13. 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

  14. 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

  15. 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

  16. 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

  17. 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

  18. 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

  19. 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

  20. 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

  1. 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

  2. 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.

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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

  12. 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.

  13. 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

  14. 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

  15. 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

  16. 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

  17. 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

  18. 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.

  19. 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

  20. 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.

  1. 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

  2. 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

  3. Discovery and characterization of two novel salt-tolerance genes in Puccinellia tenuiflora.

    PubMed

    Li, Ying; Takano, Tetsuo; Liu, Shenkui

    2014-01-01

    Puccinellia tenuiflora is a monocotyledonous halophyte that is able to survive in extreme saline soil environments at an alkaline pH range of 9-10. In this study, we transformed full-length cDNAs of P. tenuiflora into Saccharomyces cerevisiae by using the full-length cDNA over-expressing gene-hunting system to identify novel salt-tolerance genes. In all, 32 yeast clones overexpressing P. tenuiflora cDNA were obtained by screening under NaCl stress conditions; of these, 31 clones showed stronger tolerance to NaCl and were amplified using polymerase chain reaction (PCR) and sequenced. Four novel genes encoding proteins with unknown function were identified; these genes had no homology with genes from higher plants. Of the four isolated genes, two that encoded proteins with two transmembrane domains showed the strongest resistance to 1.3 M NaCl. RT-PCR and northern blot analysis of P. tenuiflora cultured cells confirmed the endogenous NaCl-induced expression of the two proteins. Both of the proteins conferred better tolerance in yeasts to high salt, alkaline and osmotic conditions, some heavy metals and H2O2 stress. Thus, we inferred that the two novel proteins might alleviate oxidative and other stresses in P. tenuiflora. PMID:25238412

  4. Salt tolerant SUV3 overexpressing transgenic rice plants conserve physicochemical properties and microbial communities of rhizosphere.

    PubMed

    Sahoo, Ranjan K; Ansari, Mohammad W; Tuteja, Renu; Tuteja, Narendra

    2015-01-01

    Key concerns in the ecological evaluation of GM crops are undesirably spread, gene flow, other environmental impacts, and consequences on soil microorganism's biodiversity. Numerous reports have highlighted the effects of transgenic plants on the physiology of non-targeted rhizospheric microbes and the food chain via causing adverse effects. Therefore, there is an urgent need to develop transgenics with insignificant toxic on environmental health. In the present study, SUV3 overexpressing salt tolerant transgenic rice evaluated in New Delhi and Cuttack soil conditions for their effects on physicochemical and biological properties of rhizosphere. Its cultivation does not affect soil properties viz., pH, Eh, organic C, P, K, N, Ca, Mg, S, Na and Fe(2+). Additionally, SUV3 rice plants do not cause any change in the phenotype, species characteristics and antibiotic sensitivity of rhizospheric bacteria. The population and/or number of soil organisms such as bacteria, fungi and nematodes were unchanged in the soil. Also, the activity of bacterial enzymes viz., dehydrogenase, invertase, phenol oxidases, acid phosphatases, ureases and proteases was not significantly affected. Further, plant growth promotion (PGP) functions of bacteria such as siderophore, HCN, salicylic acid, IAA, GA, zeatin, ABA, NH3, phosphorus metabolism, ACC deaminase and iron tolerance were, considerably, not influenced. The present findings suggest ecologically pertinent of salt tolerant SUV3 rice to sustain the health and usual functions of the rhizospheric organisms. PMID:25303666

  5. Thermal inactivation kinetics of Salmonella Enteritidis and Oranienberg in commercially acquired 10% salted liquid whole egg

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Liquid egg pasteurization requirements are based on time/temperature combinations in the Code of Federal Regulations, Title 9, Ch. III, Sec. 590.570 from data acquired prior to 1970. These guidelines are being reevaluated in light of recent risk assessments. Heat-resistant Salmonella Enteritidi...

  6. Genetic characterization of Lophopyrum elongatum salt tolerance and associated ion regulation as expressed in bread wheat. Final technical report

    SciTech Connect

    1997-10-07

    Lophopyrum elongatum is a highly salt-tolerant relative of wheat. Its salt tolerance is partially expressed in the amphiploid from a cross between wheat cv. Chinese Spring and L. elongatum. Genetic studies showed that the tolerance of gradually imposed salt stress is controlled by L. elongatum chromosomes 3E, 4E, 5E, and 7E and the tolerance of suddenly imposed salt stress by chromosomes 3E, 5E, 6E, and 7E. In wheat, rye, barley, and Dasypyrum, chromosomes of the same homoeologous groups, 3, 5, 6, and 7, were found to control the tolerance of these stress regimes. To gain insight into the physiological mechanisms of salt tolerance by wheat and L. elongatum, accumulation of Na and K, 20 protein amino acids, glycinebetaine, aminobutyrate, all TCA cycle intermediates, oxalate, glycerol-3-P, glyceraldehyde-3-P, pyruvate, lactate, ornithine, taurine, glucose, sucrose and other sugars was examined in the amphiploid and Chinese Spring by gas chromatography and H-NMR.

  7. Calcium mediates root K+/Na+ homeostasis in poplar species differing in salt tolerance.

    PubMed

    Sun, Jian; Dai, Songxiang; Wang, Ruigang; Chen, Shaoliang; Li, Niya; Zhou, Xiaoyang; Lu, Cunfu; Shen, Xin; Zheng, Xiaojiang; Hu, Zanmin; Zhang, Zengkai; Song, Jin; Xu, Yue

    2009-09-01

    Using the non-invasively ion-selective microelectrode technique, flux profiles of K(+), Na(+) and H(+) in mature roots and apical regions, and the effects of Ca(2+) on ion fluxes were investigated in salt-tolerant poplar species, Populus euphratica Oliver and salt-sensitive Populus simonii x (P. pyramidalis + Salix matsudana) (Populus popularis 35-44, P. popularis). Compared to P. popularis, P. euphratica roots exhibited a greater capacity to retain K(+) after exposure to a salt shock (SS, 100 mM NaCl) and a long-term (LT) salinity (50 mM NaCl, 3 weeks). Salt shock-induced K(+) efflux in the two species was markedly restricted by K(+) channel blocker, tetraethylammonium chloride, but enhanced by sodium orthovanadate, the inhibitor of plasma membrane (PM) H(+)-ATPase, suggesting that the K(+) efflux is mediated by depolarization-activated (DA) channels, e.g., KORCs (outward rectifying K(+) channels) and NSCCs (non-selective cation channels). Populus euphratica roots were more effective to exclude Na(+) than P. popularis in an LT experiment, resulting from the Na(+)/H(+) antiport across the PM. Moreover, pharmacological evidence implies that the greater ability to control K(+)/Na(+) homeostasis in salinized P. euphratica roots is associated with the higher H(+)-pumping activity, which provides an electrochemical H(+) gradient for Na(+)/H(+) exchange and simultaneously decreases the NaCl-induced depolarization of PM, thus reducing Na(+) influx via NSCCs and K(+) efflux through DA-KORCs and DA-NSCCs. Ca(2+) application markedly limited salt-induced K(+) efflux but enhanced the apparent Na(+) efflux, thus enabling the two species, especially the salt-sensitive poplar, to retain K(+)/Na(+) homeostasis in roots exposed to prolonged NaCl treatment. PMID:19638360

  8. Selenium accumulation and selenium tolerance of salt grass from soils with elevated concentrations of Se and salinity

    SciTech Connect

    Wu, L.; Huang, Z.Z. )

    1991-12-01

    Biomass production, selenium accumulation, and the role of the bioextraction of selenium by salt grass (Distichlis spicata L.) in soils with elevated concentrations of Se and salinity at Kesterson, California, were studied. Salt grass contributed more than 80% vegetative coverage and 90% dry weight in the grassland communities where the soil Se concentrations were 100 times (1000 to 3000 micrograms kg-1) higher than the Se concentrations found in soils of the control sites. No evidence for evolution of Se tolerance was found in the salt grass populations. The successful colonization of salt grass in the soil with elevated Se and salinity is attributable to the presence of high concentrations of soil sulfate. Salt grass accumulated less Se than other salt-tolerant plant species existing in the same area, and no predation of animals and insects on salt grass has been noticed. Salt grass can transpire substantial amounts of volatile Se through its plant tissue. Under field conditions, a 1-m2 salt grass plot may produce 180 micrograms volatile selenium per day. However, no reduction of soil Se concentration in the salt grass habitat was detected over a period of 1 year. A long-term monitoring of Se status is needed in order to make predictions of the effectiveness of efforts to clean up Se-contaminated soils through the use of native plant species.

  9. Selenium accumulation and selenium tolerance of salt grass from soils with elevated concentrations of Se and salinity.

    PubMed

    Wu, L; Huang, Z Z

    1991-12-01

    Biomass production, selenium accumulation, and the role of the bioextraction of selenium by salt grass (Distichlis spicata L.) in soils with elevated concentrations of Se and salinity at Kesterson, California, were studied. Salt grass contributed more than 80% vegetative coverage and 90% dry weight in the grassland communities where the soil Se concentrations were 100 times (1000 to 3000 micrograms kg-1) higher than the Se concentrations found in soils of the control sites. No evidence for evolution of Se tolerance was found in the salt grass populations. The successful colonization of salt grass in the soil with elevated Se and salinity is attributable to the presence of high concentrations of soil sulfate. Salt grass accumulated less Se than other salt-tolerant plant species existing in the same area, and no predation of animals and insects on salt grass has been noticed. Salt grass can transpire substantial amounts of volatile Se through its plant tissue. Under field conditions, a 1-m2 salt grass plot may produce 180 micrograms volatile selenium per day. However, no reduction of soil Se concentration in the salt grass habitat was detected over a period of 1 year. A long-term monitoring of Se status is needed in order to make predictions of the effectiveness of efforts to clean up Se-contaminated soils through the use of native plant species. PMID:1778115

  10. Adaptive response and tolerance to sugar and salt stress in the food yeast Zygosaccharomyces rouxii.

    PubMed

    Dakal, Tikam Chand; Solieri, Lisa; Giudici, Paolo

    2014-08-18

    The osmotolerant and halotolerant food yeast Zygosaccharomyces rouxii is known for its ability to grow and survive in the face of stress caused by high concentrations of non-ionic (sugars and polyols) and ionic (mainly Na(+) cations) solutes. This ability determines the success of fermentation on high osmolarity food matrices and leads to spoilage of high sugar and high salt foods. The knowledge about the genes, the metabolic pathways, and the regulatory circuits shaping the Z. rouxii sugar and salt-tolerance, is a prerequisite to develop effective strategies for fermentation control, optimization of food starter culture, and prevention of food spoilage. This review summarizes recent insights on the mechanisms used by Z. rouxii and other osmo and halotolerant food yeasts to endure salts and sugars stresses. Using the information gathered from S. cerevisiae as guide, we highlight how these non-conventional yeasts integrate general and osmoticum-specific adaptive responses under sugar and salts stresses, including regulation of Na(+) and K(+)-fluxes across the plasma membrane, modulation of cell wall properties, compatible osmolyte production and accumulation, and stress signalling pathways. We suggest how an integrated and system-based knowledge on these mechanisms may impact food and biotechnological industries, by improving the yeast spoilage control in food, enhancing the yeast-based bioprocess yields, and engineering the osmotolerance in other organisms. PMID:24973621

  11. 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

  12. 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

  13. Expression and characterization of the SOS1 Arabidopsis salt tolerance protein.

    PubMed

    Ullah, Asad; Dutta, Debajyoti; Fliegel, Larry

    2016-04-01

    SOS1 is the plasma membrane Na(+)/H(+) antiporter of Arabidopsis thaliana. It is responsible for the removal of intracellular sodium in exchange for an extracellular proton. SOS1 is composed of 1146 amino acids. Approximately 450 make the membrane domain, while the protein contains and a very large regulatory cytosolic domain of about 696 amino acids. Schizosaccharomyces pombe contains the salt tolerance Na(+)/H(+) antiporter proteins sod2. We examined the ability of SOS1 to rescue salt tolerance in S. pombe with a knockout of the sod2 gene (sod2::ura4). In addition, we characterized the importance of the regulatory tail of SOS1, in expression of the protein in S. pombe. We expressed full-length SOS1 and SOS1 shortened at the C-terminus and ending at amino acids 766 (medium) and 481 (short). The short version of SOS1 conveyed salt tolerance to sod2::ura4 yeast and Western blotting revealed that the protein was present. The protein was also targeted to the plasma membrane. The medium and full-length SOS1 protein were partially degraded and were not as well expressed as the short version of SOS1. The SOS1 short protein was also able to reduce Na(+) content in S. pombe. The full-length SOS1 dimerized and depended on the presence of the cytosolic tail. An analysis of SOS1 predicted a topology of 13 transmembrane segments, distinct from E. coli NhaA but similar to the Na(+)/H(+) exchangers Methanocaldococcus jannaschii NhaP1 and Thermus thermophile NapA. PMID:26992907

  14. Salt tolerant green crop species for sodium management in space agriculture

    NASA Astrophysics Data System (ADS)

    Yamashita, Masamichi; Hashimoto, Hirofumi; Tomita-Yokotani, Kaori; Shimoda, Toshifumi; Nose, Akihiro; Space Agriculture Task Force, J.

    Ecological system and materials recycling loop of space agriculture are quite tight compared to natural ecological system on Earth. Sodium management will be a keen issue for space agricul-ture. Human nutritional requirements include sodium salt. Since sodium at high concentration is toxic for most of plant growth, excreted sodium of human waste should be removed from compost fertilizer. Use of marine algae is promising for harvesting potassium and other min-erals required for plant growth and returning remained sodium to satisfy human need of its intake. Farming salt tolerant green crop species is another approach to manage sodium problem in both space and terrestrial agriculture. We chose ice plant and New Zealand spinach. These two plant species are widely accepted green vegetable with many recipe. Ice plant can grow at the salinity level of sea water, and contain sodium salt up to 30% of its dry mass. Sodium distributes mainly in its bladder cells. New Zealand spinach is a plant species found in the front zone of sea shore, and tolerant against high salinity as well. Plant body size of both species at harvest is quite large, and easy to farm. Capability of bio-remediation of high saline soil is examined with ice plant and New Zealand spinach. Incubation medium was chosen to contain high concentration of sodium and potassium at the Na/K ratio of human excreta. In case Na/K ratio of plant body grown by this medium is greatly higher than that of incubation medium or soil, these halophytes are effective to remediate soil for farming less tolerant plant crop. Experimental results was less positive in this context.

  15. The Arabidopsis RNA-binding protein AtRGGA regulates tolerance to salt and drought stress.

    PubMed

    Ambrosone, Alfredo; Batelli, Giorgia; Nurcato, Roberta; Aurilia, Vincenzo; Punzo, Paola; Bangarusamy, Dhinoth Kumar; Ruberti, Ida; Sassi, Massimiliano; Leone, Antonietta; Costa, Antonello; Grillo, Stefania

    2015-05-01

    Salt and drought stress severely reduce plant growth and crop productivity worldwide. The identification of genes underlying stress response and tolerance is the subject of intense research in plant biology. Through microarray analyses, we previously identified in potato (Solanum tuberosum) StRGGA, coding for an Arginine Glycine Glycine (RGG) box-containing RNA-binding protein, whose expression was specifically induced in potato cell cultures gradually exposed to osmotic stress. Here, we show that the Arabidopsis (Arabidopsis thaliana) ortholog, AtRGGA, is a functional RNA-binding protein required for a proper response to osmotic stress. AtRGGA gene expression was up-regulated in seedlings after long-term exposure to abscisic acid (ABA) and polyethylene glycol, while treatments with NaCl resulted in AtRGGA down-regulation. AtRGGA promoter analysis showed activity in several tissues, including stomata, the organs controlling transpiration. Fusion of AtRGGA with yellow fluorescent protein indicated that AtRGGA is localized in the cytoplasm and the cytoplasmic perinuclear region. In addition, the rgga knockout mutant was hypersensitive to ABA in root growth and survival tests and to salt stress during germination and at the vegetative stage. AtRGGA-overexpressing plants showed higher tolerance to ABA and salt stress on plates and in soil, accumulating lower levels of proline when exposed to drought stress. Finally, a global analysis of gene expression revealed extensive alterations in the transcriptome under salt stress, including several genes such as ASCORBATE PEROXIDASE2, GLUTATHIONE S-TRANSFERASE TAU9, and several SMALL AUXIN UPREGULATED RNA-like genes showing opposite expression behavior in transgenic and knockout plants. Taken together, our results reveal an important role of AtRGGA in the mechanisms of plant response and adaptation to stress. PMID:25783413

  16. Taxonomic homogeneity of a salt-tolerant lactic acid bacteria isolated from shoyu mash.

    PubMed

    Hanagata, Hiroshi; Shida, Osamu; Takagi, Hiroaki

    2003-04-01

    Forty-seven salt-tolerant lactic acid bacteria, which had been isolated from different places and grown in 15% NaCl, were examined to assess their taxonomic heterogeneity. Among the isolates, 42 were isolated from shoyu mash during the acid fermentation phase, 2 were from miso and 3 were from anchovy pickles. All isolates were identified as Tetragenococcus halophilus on the basis of DNA relatedness values. We further examined 102 phenotypic characteristics of them. The isolates exhibited differences in only 16, supporting the conclusion obtained from the DNA relatedness analysis. PMID:12833212

  17. 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

  18. 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.

  19. 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

  20. Detection of QTLs for salt tolerance in Asian barley (Hordeum vulgare L.) by association analysis with SNP markers

    PubMed Central

    Sbei, Hanen; Sato, Kazuhiro; Shehzad, Tariq; Harrabi, Moncef; Okuno, Kazutoshi

    2014-01-01

    Two hundred ninety-six Asian barley (Hordeum vulgare L.) accessions were assessed to detect QTLs underlying salt tolerance by association analysis using a 384 single nucleotide polymorphism (SNP) marker system. The experiment was laid out at the seedling stage in a hydroponic solution under control and 250 mM NaCl solution with three replications of four plants each. Salt tolerance was assessed by leaf injury score (LIS) and salt tolerance indices (STIs) of the number of leaves (NL), shoot length (SL), root length (RL), shoot dry weight (SDW) and root dry weight (RDW). LIS was scored from 1 to 5 according to the severity of necrosis and chlorosis observed on leaves. There was a wide variation in salt tolerance among Asian barley accessions. LIS and STI (SDW) were the most suitable traits for screening salt tolerance. Association was estimated between markers and traits to detect QTLs for LIS and STI (SDW). Seven significant QTLs were located on chromosomes 1H (2 QTLs), 2H (2 QTLs), 3H (1 QTL), 4H (1 QTL) and 5H (1 QTL). Five QTLs were associated with LIS and 2 QTLs with STI (SDW). Two QTLs associated with LIS were newly identified on chromosomes 3H and 4H. PMID:25914593

  1. 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

  2. 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

  3. 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

  4. [Selection and identification of salt tolerant line of sainfoin from the seeds of first post-flight plants].

    PubMed

    Xu, Y Y; Wang, M G; Jia, J F

    2001-03-01

    Seeds of sainfoin (Onobrychis vicaefolia Scop.) were carried in the recoverable satellite 940703 and recovered from earth orbit from China in 1994. The progeny seeds were obtained by producing in field. The salt tolerant calluses were selected by screening seedling and callus on 1.5% NaCl-containing medium, reviving growth on NaCl- free medium and selecting callus on 1.2% NaCl-containing medium. The salt tolerant line callus maintained the normal ability to regenerate plant. The salt tolerant line callus exhibited cross-resistance to PEG stress. The variant appeared higher efficiency than control to accumulate proline under salt stress, however, under nonstress condition it had lower proline level than control, which suggested that the higher efficiency to synthesize proline under stress condition may be more important than higher level in tissue under nonstress condition. The mechanism of proline synthesis in the selected callus was considered to result from the alteration in gene sensitivity to water regulation at transcription level. Acrylamide gradient electrophoresis showed that new isoenzyme form with MW 175 kD and 75 kD of superoxide dismutase and esterase respectively appeared in salt torlerant callus. It was indicated that the combination of space mutagenesis with tissue culture could be used for the selection of salt tolerant sainfoin line in vitro. PMID:12549005

  5. 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

  6. Improving salt tolerance of lowland rice cultivar 'Rassi' through marker-aided backcross breeding in West Africa.

    PubMed

    Bimpong, Isaac Kofi; Manneh, Baboucarr; Sock, Mamadou; Diaw, Faty; Amoah, Nana Kofi Abaka; Ismail, Abdelbagi M; Gregorio, Glenn; Singh, Rakesh Kumar; Wopereis, Marco

    2016-01-01

    Salt stress affects about 25% of the 4.4 million ha of irrigated and lowland systems for rice cultivation in West Africa (WA). A major quantitative trait locus (QTLs) on chromosome 1 (Saltol) that enhances tolerance to salt stress at the vegetative stage has enabled the use of marker-assisted selection (MAS) to develop salt-tolerant rice cultivar(s) in WA. We used 3 cycles of backcrossing with selection based on DNA markers and field-testing using 'FL478' as tolerant donor and the widely grown 'Rassi' as recurrent parent. In the BC3F2 stage, salt-tolerant lines with over 80% Rassi alleles except in the region around Saltol segment were selected. 429 introgression lines (Saltol-ILs) were identified as tolerant at vegetative stage, of which 116 were field-tested for four seasons at the reproductive stage. Sixteen Saltol-ILs had less yield loss (3-26% relative to control trials), and 8 Saltol-ILs showed high yield potential under stress and non-stress conditions. The 16 Saltol-ILs had been included for further African-wide testing prior to release in 6 WA countries. MAS reduced the time for germplasm improvement from at least 7 to about 4 years. Our objective is to combine different genes/QTLs conferring tolerance to stresses under one genetic background using MAS. PMID:26566846

  7. Salt-tolerant phenol-degrading microorganisms isolated from Amazonian soil samples.

    PubMed

    Bastos, A E; Moon, D H; Rossi, A; Trevors, J T; Tsai, S M

    2000-11-01

    Two phenol-degrading microorganisms were isolated from Amazonian rain forest soil samples after enrichment in the presence of phenol and a high salt concentration. The yeast Candida tropicalis and the bacterium Alcaligenes faecoalis were identified using several techniques, including staining, morphological observation and biochemical tests, fatty acid profiles and 16S/18S rRNA sequencing. Both isolates, A. faecalis and C. tropicalis, were used in phenol degradation assays, with Rhodococcus erythropolis as a reference phenol-degrading bacterium, and compared to microbial populations from wastewater samples collected from phenol-contaminated environments. C. tropicalis tolerated higher concentrations of phenol and salt (16 mM and 15%, respectively) than A. faecalis (12 mM and 5.6%). The yeast also tolerated a wider pH range (3-9) during phenol degradation than A. faecalis (pH 7-9). Phenol degradation was repressed in C. tropicalis by acetate and glucose, but not by lactate. Glucose and acetate had little effect, while lactate stimulated phenol degradation in A. faecalis. To our knowledge, these soils had never been contaminated with man-made phenolic compounds and this is the first report of phenol-degrading microorganisms from Amazonian forest soil samples. The results support the idea that natural uncontaminated environments contain sufficient genetic diversity to make them valid choices for the isolation of microorganisms useful in bioremediation. PMID:11131025

  8. 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

  9. 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

  10. 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

  11. Induction of salt tolerance in Azolla microphylla Kaulf through modulation of antioxidant enzymes and ion transport.

    PubMed

    Abraham, Gerard; Dhar, Dolly Wattal

    2010-09-01

    Azolla microphylla plants exposed directly to NaCl (13 dsm(-1)) did not survive the salinity treatment beyond a period of one day, whereas plants exposed directly to 4 and 9 dsm(-1) NaCl were able to grow and produce biomass. However, plants pre-exposed to NaCl (2 dsm(-1)) for 7 days on subsequent exposure to 13 dsm(-1) NaCl were able to grow and produce biomass although at a slow rate and are hereinafter designated as pre-exposed plants. The pre-exposed and directly exposed plants distinctly differed in their response to salt in terms of lipid peroxidation, proline accumulation, activity of antioxidant enzymes, such as SOD, APX, and CAT, and Na(+)/K(+) ratio. Efficient modulation of antioxidant enzymes coupled with regulation of ion transport play an important role in the induction of salt tolerance. Results show that it is possible to induce salt adaptation in A. microphylla by pre-exposing them to low concentrations of NaCl. PMID:20422236

  12. A novel gene, lstC, of Listeria monocytogenes is implicated in high salt tolerance.

    PubMed

    Burall, Laurel S; Simpson, Alexandra C; Chou, Luoth; Laksanalamai, Pongpan; Datta, Atin R

    2015-06-01

    Listeria monocytogenes, causative agent of human listeriosis, has been isolated from a wide variety of foods including deli meats, soft cheeses, cantaloupes, sprouts and canned mushrooms. Standard control measures for restricting microbial growth such as refrigeration and high salt are often inadequate as L. monocytogenes grows quite well in these environments. In an effort to better understand the genetic and physiological basis by which L. monocytogenes circumvents these controls, a transposon library of L. monocytogenes was screened for changes in their ability to grow in 7% NaCl and/ or at 5 °C. This work identified a transposon insertion upstream of an operon, here named lstABC, that led to a reduction in growth in 7% NaCl. In-frame deletion studies identified lstC which codes for a GNAT-acetyltransferase being responsible for the phenotype. Transcriptomic and RT-PCR analyses identified nine genes that were upregulated in the presence of high salt in the ΔlstC mutant. Further analysis of lstC and the genes affected by ΔlstC is needed to understand LstC's role in salt tolerance. PMID:25790994

  13. 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.

  14. 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

  15. 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

  16. Saccharomyces cerevisiae BY4741 and W303-1A laboratory strains differ in salt tolerance.

    PubMed

    Petrezselyova, Silvia; Zahradka, Jaromir; Sychrova, Hana

    2010-01-01

    Saccharomyces cerevisiae yeast cells serve as a model to elucidate the bases of salt tolerance and potassium homeostasis regulation in eukaryotic cells. In this study, we show that two widely used laboratory strains, BY4741 and W303-1A, differ not only in cell size and volume but also in their relative plasma-membrane potential (estimated with a potentiometric fluorescent dye diS-C3(3) and as Hygromycin B sensitivity) and tolerance to alkali-metal cations. W303-1A cells and their mutant derivatives lacking either uptake (trk1 trk2) or efflux (nha1) systems for alkali-metal cations are more tolerant to toxic sodium and lithium cations but also more sensitive to higher external concentrations of potassium than BY4741 cells and their mutants. Moreover, our results suggest that though the two strains do not differ in the total potassium content, the regulation of intracellular potassium homeostasis is probably not the same in BY4741 and W303-1A cells. PMID:20960970

  17. 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

  18. 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

  19. 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

  20. Heterologous expression of the halophyte Zoysia matrella H⁺-pyrophosphatase gene improved salt tolerance in Arabidopsis thaliana.

    PubMed

    Chen, Yu; Li, Lanlan; Zong, Junqin; Chen, Jingbo; Guo, Hailin; Guo, Aigui; Liu, Jianxiu

    2015-06-01

    A number of vacuolar H(+)-pyrophosphatase (VP) family genes play important roles in plant growth under salt stress condition. Despite their biological importance in plant salt-stress regulation, there is no report about VP in the halophytic turfgrass Zoysia matrella. Here, we isolated ZmVP1, a type I VP homologues gene encoding 768 amino acids by using the degenerated PCR and RACE PCR methods from Zoysia matrella. The expression level of ZmVP1 was significantly induced by salinity, drought and cold, but not by heat. ZmVP1 can restore the salt-tolerant ability of a salt-sensitive yeast strain. Overexpression of ZmVP1 in Arabidopsis thaliana resulted in more vigorous growth under salt stress. Moreover, the transgenic Arabidopsis accumulated more Na(+) and K(+) in the leaves compared to that of wild type plants under salt stress, had higher activities of V-ATPase and V-PPase, and showed higher relative gene expression levels of 5 stress-related genes (AtNHX1, AtLEA, AtP5CS, AtMn-SOD, AtAPX1). These results demonstrated that ZmVP1 from Z. matrella was a functional tonoplast H(+)-pyrophosphatase contributing to salt tolerance potentially through regulating the Na(+) compartment in vacuole, K(+) assimilation, osmotic regulation and antioxidant response. PMID:25874657

  1. Genetic variation in salt tolerance during seed germination in a backcross inbred line population and advanced breeding lines derived from upland cotton x pima cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seed germination is a crucial phase of the plant life cycle that affects its establishment and productivity. However, information on salt tolerance at this phase is limited. Pima cotton (Gossypium barbadense L.) may be more salt tolerant during germination than Upland cotton (G. hirsutum L.) based o...

  2. 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

  3. 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

  4. Protein S-ACYL Transferase10 is critical for development and salt tolerance in Arabidopsis.

    PubMed

    Zhou, Liang-Zi; Li, Sha; Feng, Qiang-Nan; Zhang, Yu-Ling; Zhao, Xinying; Zeng, Yong-lun; Wang, Hao; Jiang, Liwen; Zhang, Yan

    2013-03-01

    Protein S-acylation, commonly known as palmitoylation, is a reversible posttranslational modification that catalyzes the addition of a saturated lipid group, often palmitate, to the sulfhydryl group of a Cys. Palmitoylation regulates enzyme activity, protein stability, subcellular localization, and intracellular sorting. Many plant proteins are palmitoylated. However, little is known about protein S-acyl transferases (PATs), which catalyze palmitoylation. Here, we report that the tonoplast-localized PAT10 is critical for development and salt tolerance in Arabidopsis thaliana. PAT10 loss of function resulted in pleiotropic growth defects, including smaller leaves, dwarfism, and sterility. In addition, pat10 mutants are hypersensitive to salt stresses. We further show that PAT10 regulates the tonoplast localization of several calcineurin B-like proteins (CBLs), including CBL2, CBL3, and CBL6, whose membrane association also depends on palmitoylation. Introducing a C192S mutation within the highly conserved catalytic motif of PAT10 failed to complement pat10 mutants, indicating that PAT10 functions through protein palmitoylation. We propose that PAT10-mediated palmitoylation is critical for vacuolar function by regulating membrane association or the activities of tonoplast proteins. PMID:23482856

  5. 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

  6. 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

  7. A synergistic interaction between salt-tolerant Pseudomonas and Mesorhizobium strains improves growth and symbiotic performance of liquorice (Glycyrrhiza uralensis Fish.) under salt stress.

    PubMed

    Egamberdieva, Dilfuza; Li, Li; Lindström, Kristina; Räsänen, Leena A

    2016-03-01

    Chinese liquorice (Glycyrrhiza uralensis Fish.) is a salt-tolerant medicinal legume that could be utilized for bioremediation of salt-affected soils. We studied whether co-inoculation of the symbiotic Mesorhizobium sp. strain NWXJ19 or NWXJ31 with the plant growth-promoting Pseudomonas extremorientalis TSAU20 could restore growth, nodulation, and shoot/root nitrogen contents of salt-stressed G. uralensis, which was grown in potting soil and irrigated with 0, 50, and 75 mM NaCl solutions under greenhouse conditions. Irrigation with NaCl solutions clearly retarded the growth of uninoculated liquorice, and the higher the NaCl concentration (75 and 100 mM NaCl), the more adverse is the effect. The two Mesorhizobium strains, added either alone or in combination with P. extremorientalis TSAU20, responded differently to the salt levels used. The strain NWXJ19 was a good symbiont for plants irrigated with 50 mM NaCl, whereas the strain NWXJ31 was more efficient for plants irrigated with water or 75 mM NaCl solution. P. extremorientalis TSAU20 combined with single Mesorhizobium strains alleviated the salt stress of liquorice plants and improved yield and nodule numbers significantly in comparison with single-strain-inoculated liquorice. Both salt stress and inoculation raised the nitrogen content of shoots and roots. The nitrogen contents were at their highest, i.e., 30 and 35 % greater compared to non-stressed uninoculated plants, when plants were inoculated with P. extremorientalis TSAU20 and Mesorhizobium sp. NWXJ31 as well as irrigated with 75 mM NaCl solution. From this study, we conclude that dual inoculation with plant growth-promoting rhizobacteria could be a new approach to improve the tolerance of G. uralensis to salt stress, thereby improving its suitability for the remediation of saline lands. PMID:26585446

  8. 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

  9. 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

  10. Comparative expression analysis of Calcineurin B-like family gene CBL10A between salt-tolerant and salt-sensitive cultivars in B. oleracea.

    PubMed

    Xu, Ling; Zhang, Dayong; Xu, Zhaolong; Huang, Yihong; He, Xiaolan; Wang, Jinyan; Gu, Minfeng; Li, Jianbin; Shao, Hongbo

    2016-11-15

    Calcineurin B-like proteins (CBLs) are plant calcium sensors that play a critical role in the regulation of plant growth and response to stress. Many CBLs have been identified in the calcium signaling pathway in both Arabidopsis and rice. However, information about BoCBLs genes from Brassica oleracea has not been reported. In the present study, we identified 13 candidate CBL genes in the B. oleracea genome based on the conserved domain of the Calcineurin B-like family, and we carried out a phylogenetic analysis of CBLs among Arabidopsis, rice, maize, cabbage and B. oleracea. For B. oleracea, the distribution of the predicted BoCBL genes was uneven among the five chromosomes. Sequence analysis showed that the nucleotide sequences and corresponding protein structure of BoCBLs were highly conserved, i.e., all of the putative BoCBLs contained 6-8 introns, and most of the exons of those genes contained the same number of nucleotides and had high sequence identities. All BoCBLs consisted of four EF-Hand functional domains, and the distance between the EF-hand motifs was conserved. Evolutionary analysis revealed that the CBLs were classified into two subgroups. Additionally, the CBL10A gene was cloned from salt-tolerant (CB6) and salt-sensitive (CB3) cultivars using RT-PCR. The results indicated that the cloned gene had a substantial difference in length (741bp in CB3 and 829bp in CB6) between these two cultivars. The deduced CBL10A protein in CB6 had four EF-hand structural domains, which have an irreplaceable role in calcium-binding and have calcineurin A subunit binding sites, while the BoCBL10A protein in CB3 had only two EF-hand structural domains and lacked calcineurin A subunit binding sites. The expression level of the BoCBL10A gene between salt tolerance (CB6)and sensitive varieties(CB3) under salt stress was significantly different (P<0.01 and P<0.05). The expression of BoCBL10A gene was relatively higher in salt-tolerant (CB6) cultivar under salt stress, with a

  11. Draft Genome Sequence of Bacillus plakortidis P203T (DSM 19153), an Alkali- and Salt-Tolerant Marine Bacterium

    PubMed Central

    Wang, Jie-ping; Liu, Guo-hong; Ge, Ci-bin; Xiao, Rong-feng; Zheng, Xue-fang; Shi, Huai

    2016-01-01

    Bacillus plakortidis P203T is a Gram-positive, spore-forming, and alkali- and salt-tolerant marine bacterium. Here, we report the 3.97-Mb draft genome sequence of B. plakortidis P203T, which will promote its fundamental research and provide useful information for genomic taxonomy and phylogenomics of Bacillus-like bacteria. PMID:26847896

  12. De Novo Transcriptome Sequencing of Desert Herbaceous Achnatherum splendens (Achnatherum) Seedlings and Identification of Salt Tolerance Genes

    PubMed Central

    Liu, Jiangtao; Zhou, Yuelong; Luo, Changxin; Xiang, Yun; An, Lizhe

    2016-01-01

    Achnatherum splendens is an important forage herb in Northwestern China. It has a high tolerance to salinity and is, thus, considered one of the most important constructive plants in saline and alkaline areas of land in Northwest China. However, the mechanisms of salt stress tolerance in A. splendens remain unknown. Next-generation sequencing (NGS) technologies can be used for global gene expression profiling. In this study, we examined sequence and transcript abundance data for the root/leaf transcriptome of A. splendens obtained using an Illumina HiSeq 2500. Over 35 million clean reads were obtained from the leaf and root libraries. All of the RNA sequencing (RNA-seq) reads were assembled de novo into a total of 126,235 unigenes and 36,511 coding DNA sequences (CDS). We further identified 1663 differentially-expressed genes (DEGs) between the salt stress treatment and control. Functional annotation of the DEGs by gene ontology (GO), using Arabidopsis and rice as references, revealed enrichment of salt stress-related GO categories, including “oxidation reduction”, “transcription factor activity”, and “ion channel transporter”. Thus, this global transcriptome analysis of A. splendens has provided an important genetic resource for the study of salt tolerance in this halophyte. The identified sequences and their putative functional data will facilitate future investigations of the tolerance of Achnatherum species to various types of abiotic stress. PMID:27023614

  13. Long-Term Tolerability and Effectiveness of Once-Daily Mixed Amphetamine Salts (Adderall XR) in Children with ADHD

    ERIC Educational Resources Information Center

    McGough, James J.; Biederman, Joseph; Wigal, Sharon B.; Lopez, Frank A.; McCracken, James T.; Spencer, Thomas; Zhang, Yuxin; Tulloch, Simon J.

    2005-01-01

    Objective: To evaluate the long-term tolerability and effectiveness of extended-release mixed amphetamine salts (MAS XR; Adderall XR[R]) in children with attention-deficit/hyperactivity disorder (ADHD). Method: This was a 24-month, multicenter, open-label extension of TWO placebo-controlled studies of MAS XR in children with ADHD aged 6 to 12…

  14. Genetic variation in salt tolerance at the seedling stage in an interspecific backcross inbred line population of cultivated tetraploid cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil salinity reduces cotton growth, yield, and fiber quality and has become a serious problem in the arid southwestern region of the Unites States. Development and planting of salt-tolerant cultivars could ameliorate the deleterious effects. The objectives of this study were to assess the genetic v...

  15. Molecular Breeding to Improve Salt Tolerance of Rice (Oryza sativa L.) in the Red River Delta of Vietnam

    PubMed Central

    Linh, Le Hung; Linh, Ta Hong; Xuan, Tran Dang; Ham, Le Huy; Ismail, Abdelbagi M.; Khanh, Tran Dang

    2012-01-01

    Rice is a stable food in Vietnam and plays a key role in the economy of the country. However, the production and the cultivating areas are adversely affected from the threats of devastation caused by the rise of sea level. Using marker-assisted backcrossing (MABC) to develop a new salt tolerance rice cultivar is one of the feasible methods to cope with these devastating changes. To improve rice salt tolerance in BT7 cultivar, FL478 was used as a donor parent to introgress the Saltol QTL conferring salt tolerance into BT7. Three backcrosses were conducted and successfully transferred positive alleles of Saltol from FL478 into BT7. The plants numbers IL-30 and IL-32 in BC3F1 population expected recurrent genome recovery of up to 99.2% and 100%, respectively. These selected lines that carried the Saltol alleles were screened in field for their agronomic traits. All improved lines had Saltol allele similar to the donor parent FL478, whereas their agronomic performances were the same as the original BT7. We show here the success of improving rice salt tolerance by MABC and the high efficiency of selection in early generations. In the present study, MABC has accelerated the development of superior qualities in the genetic background of BT7. PMID:23326259

  16. 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...

  17. Expression of an Arabidopsis sodium/proton antiporter gene (AtNHX1)in peanut to improve salt tolerance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salinity is a major environmental stress that affects agricultural productivity worldwide. One approach to improving salt tolerance in crops is through high expression of the Arabidopsis gene AtNHX1, which encodes a vacuolar sodium/proton antiporter that sequesters excess sodium ion into the large i...

  18. De Novo Transcriptome Sequencing of Desert Herbaceous Achnatherum splendens (Achnatherum) Seedlings and Identification of Salt Tolerance Genes.

    PubMed

    Liu, Jiangtao; Zhou, Yuelong; Luo, Changxin; Xiang, Yun; An, Lizhe

    2016-01-01

    Achnatherum splendens is an important forage herb in Northwestern China. It has a high tolerance to salinity and is, thus, considered one of the most important constructive plants in saline and alkaline areas of land in Northwest China. However, the mechanisms of salt stress tolerance in A. splendens remain unknown. Next-generation sequencing (NGS) technologies can be used for global gene expression profiling. In this study, we examined sequence and transcript abundance data for the root/leaf transcriptome of A. splendens obtained using an Illumina HiSeq 2500. Over 35 million clean reads were obtained from the leaf and root libraries. All of the RNA sequencing (RNA-seq) reads were assembled de novo into a total of 126,235 unigenes and 36,511 coding DNA sequences (CDS). We further identified 1663 differentially-expressed genes (DEGs) between the salt stress treatment and control. Functional annotation of the DEGs by gene ontology (GO), using Arabidopsis and rice as references, revealed enrichment of salt stress-related GO categories, including "oxidation reduction", "transcription factor activity", and "ion channel transporter". Thus, this global transcriptome analysis of A. splendens has provided an important genetic resource for the study of salt tolerance in this halophyte. The identified sequences and their putative functional data will facilitate future investigations of the tolerance of Achnatherum species to various types of abiotic stress. PMID:27023614

  19. Transgenic petunia with the iron(III)-phytosiderophore transporter gene acquires tolerance to iron deficiency in alkaline environments.

    PubMed

    Murata, Yoshiko; Itoh, Yoshiyuki; Iwashita, Takashi; Namba, Kosuke

    2015-01-01

    Iron is an essential nutrient for all plants. However, terrestrial plants often suffer from iron deficiency in alkaline soil due to its extremely low solubility. Alkaline soil accounts for about 30% of all cultivated ground in the world. Plants have evolved two distinct strategies, I and II, for iron uptake from the soil. Dicots and non-graminaceous monocots use Strategy I, which is primarily based on the reduction of iron(III) to iron(II) and the uptake of iron(II) by the iron-regulated transporter, IRT1. In contrast, graminaceous plants use Strategy II to efficiently acquire insoluble iron(III). Strategy II comprises the synthesis and secretion of iron-chelating phytosiderophores, such as mugineic acids and the Yellow Stripe 1 transporter proteins of the iron(III)-phytosiderophore complex. Barley, which exhibits the highest tolerance to iron deficiency in alkaline soil among graminaceous plants, utilizes mugineic acids and the specific iron(III)-mugineic acids transporter, HvYS1. In this study, we established the transgenic plant Petunia hybrida, which originally had only Strategy I, by introducing the HvYS1 transporter gene derived from barley. When the transgenic plants were grown hydroponically in media containing the iron(III)-2'-deoxymugineic acid complex, free 2'-deoxymugineic acid and its iron(III) complex were detected in the root extract of the transgenic plant by electrospray ionization-Fourier transform-ion cyclotron resonance mass spectrometry. The growth of the transgenic petunia was significantly better than that of the control host in alkaline conditions. Consequently, the transgenic plant acquired a significantly enhanced tolerance to alkaline hydroponic media in the presence of the iron(III)-2'-deoxymugineic acid complex. Furthermore, the flower color of the transgenic plant deepened. The results showed that iron-phytosiderophore complexes and their transporters can potentially be utilized to overcome the worldwide iron uptake problems to diverse

  20. Arabidopsis Fatty Acid Desaturase FAD2 Is Required for Salt Tolerance during Seed Germination and Early Seedling Growth

    PubMed Central

    Sun, Jian; Li, Bei; Zhu, Qiang; Chen, Shaoliang; Zhang, Hongxia

    2012-01-01

    Fatty acid desaturases play important role in plant responses to abiotic stresses. However, their exact function in plant resistance to salt stress is unknown. In this work, we provide the evidence that FAD2, an endoplasmic reticulum localized ω-6 desaturase, is required for salt tolerance in Arabidopsis. Using vacuolar and plasma membrane vesicles prepared from the leaves of wild-type (Col-0) and the loss-of-function Arabidopsis mutant, fad2, which lacks the functional FAD2, we examined the fatty acid composition and Na+-dependent H+ movements of the isolated vesicles. We observed that, when compared to Col-0, the level of vacuolar and plasma membrane polyunsaturation was lower, and the Na+/H+ exchange activity was reduced in vacuolar and plasma membrane vesicles isolated from fad2 mutant. Consistent with the reduced Na+/H+ exchange activity, fad2 accumulated more Na+ in the cytoplasm of root cells, and was more sensitive to salt stress during seed germination and early seedling growth, as indicated by CoroNa-Green staining, net Na+ efflux and salt tolerance analyses. Our results suggest that FAD2 mediated high-level vacuolar and plasma membrane fatty acid desaturation is essential for the proper function of membrane attached Na+/H+ exchangers, and thereby to maintain a low cytosolic Na+ concentration for salt tolerance during seed germination and early seedling growth in Arabidopsis. PMID:22279586

  1. 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

  2. Characterization of a salt-tolerant bacterium Bacillus sp. from a membrane bioreactor for saline wastewater treatment.

    PubMed

    Zhang, Xiaohui; Gao, Jie; Zhao, Fangbo; Zhao, Yuanyuan; Li, Zhanshuang

    2014-06-01

    High salt concentrations can cause plasmolysis and loss of activity of cells, but the salt-tolerant bacterium can endure the high salt concentrations in wastewater. In this research 7 salt-tolerant bacteria, which could survive in dry powder products and could degrade organic contaminants in saline wastewater, were isolated from a membrane bioreactor. The strain NY6 which showed the fastest growth rate, best property for organic matter degradation and could survive in dry powder more than 3 months was selected and characterized. It was classified as Bacillus aerius based on the analysis of the morphological and physiological properties as well as the 16S rRNA sequence and Neigh borjoining tree. The strain NY6 could survive in the salinity up to 6% and the optimal growth salinity is 2%; it belongs to a slightly halophilic bacterium. The capability of its dry powder products for COD removal was 800 mg COD/(g·day) in synthesized saline wastewater with salinity of 2%. According to salt-tolerant mechanism research, when the salinity was below 2%, the stain NY6 absorbed K(+) and Na(+) to maintain osmotic equilibrium, and when the salinity was above 2%, the NY6 kept its life by producing a large amount of spores. PMID:25079850

  3. 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

  4. 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

  5. β-amyloid infusion into lateral ventricle alters behavioral thermoregulation and attenuates acquired heat tolerance in rats

    PubMed Central

    Matsuzaki, Kentaro; Katakura, Masanori; Sugimoto, Naotoshi; Hara, Toshiko; Hashimoto, Michio; Shido, Osamu

    2015-01-01

    We investigated behavioral thermoregulatory function and acquired heat tolerance of β-amyloid (Aβ)-infused rats. Male Wistar rats were anesthetized and implanted in the intraperitoneal cavity with a temperature transmitter. Aβ peptide (4.9–5.5 nmol) was dissolved in a solvent of 35% acetonitrile and 0.1% trifluoroacetic acid (pH 2.0). The solvent was used as the vehicle. An osmotic pump contained 234 ± 13.9 μl of Aβ solution was subcutaneously implanted in the back and was cannulated into the left cerebral ventricle. Moreover, 0.5 µg of AlCl3 was injected into the right cerebral ventricle with a micro syringe pump (Aβ-infused rats). The solvent-infused rats were used as control rats (CN rats). After 2 weeks, rats were placed in a thermal gradient and their intra-abdominal temperature (Tab) and their ambient temperatures (Ta) selected (Ts) were measured for 3 consecutive days. In an additional study, rats were kept at a Ta of 32°C for 4 weeks to attain heat acclimation. Then, rats were subjected to a heat tolerance test, i.e. they were exposed to a Ta of 36°C for 160 min. Although there were clear day-night variations of Ts and Tab in CN rats, patterns were significantly abolished in Aβ-infused rats. Moreover, heat tolerance obtained by heat acclimation was attenuated in Aβ-infused rats. These results suggest that Aβ-infusion in the lateral ventricle modifies behavioral thermoregulation and lowers an ability to acclimate to heat in rats. PMID:27227055

  6. β-amyloid infusion into lateral ventricle alters behavioral thermoregulation and attenuates acquired heat tolerance in rats.

    PubMed

    Matsuzaki, Kentaro; Katakura, Masanori; Sugimoto, Naotoshi; Hara, Toshiko; Hashimoto, Michio; Shido, Osamu

    2015-01-01

    We investigated behavioral thermoregulatory function and acquired heat tolerance of β-amyloid (Aβ)-infused rats. Male Wistar rats were anesthetized and implanted in the intraperitoneal cavity with a temperature transmitter. Aβ peptide (4.9-5.5 nmol) was dissolved in a solvent of 35% acetonitrile and 0.1% trifluoroacetic acid (pH 2.0). The solvent was used as the vehicle. An osmotic pump contained 234 ± 13.9 μl of Aβ solution was subcutaneously implanted in the back and was cannulated into the left cerebral ventricle. Moreover, 0.5 µg of AlCl3 was injected into the right cerebral ventricle with a micro syringe pump (Aβ-infused rats). The solvent-infused rats were used as control rats (CN rats). After 2 weeks, rats were placed in a thermal gradient and their intra-abdominal temperature (T ab ) and their ambient temperatures (T a ) selected (T s ) were measured for 3 consecutive days. In an additional study, rats were kept at a T a of 32°C for 4 weeks to attain heat acclimation. Then, rats were subjected to a heat tolerance test, i.e. they were exposed to a T a of 36°C for 160 min. Although there were clear day-night variations of T s and T ab in CN rats, patterns were significantly abolished in Aβ-infused rats. Moreover, heat tolerance obtained by heat acclimation was attenuated in Aβ-infused rats. These results suggest that Aβ-infusion in the lateral ventricle modifies behavioral thermoregulation and lowers an ability to acclimate to heat in rats. PMID:27227055

  7. 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

  8. 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

  9. A novel salt-inducible gene SbSI-1 from Salicornia brachiata confers salt and desiccation tolerance in E. coli.

    PubMed

    Yadav, Narendra Singh; Rashmi, Deo; Singh, Dinkar; Agarwal, Pradeep K; Jha, Bhavanath

    2012-02-01

    Salicornia brachiata is one of the extreme salt tolerant plants and grows luxuriantly in coastal areas. Previously we have reported isolation and characterization of ESTs from S. brachiata with large number of unknown gene sequences. Reverse Northern analysis showed upregulation and downregulation of few unknown genes in response to salinity. Some of these unknown genes were made full length and their functional analysis is being tested. In this study, we have selected a novel unknown salt inducible gene SbSI-1 (Salicornia brachiata salt inducible-1) for the functional validation. The SbSI-1 (Gen-Bank accession number JF 965339) was made full length and characterized in detail for its functional validation under desiccation and salinity. The SbSI-1 gene is 917 bp long, and contained 437 bp 3' UTR, and 480 bp ORF region encoding 159 amino acids protein with estimated molecular mass of 18.39 kDa and pI 8.58. The real time PCR analysis revealed high transcript expression in salt, desiccation, cold and heat stresses. However, the maximum expression was obtained by desiccation. The ORF region of SbSI-1 was cloned in pET28a vector and transformed in BL21 (DE3) E. coli cells. The SbSI-1 recombinant E. coli cells showed tolerance to desiccation and salinity stress compared to only vector in the presence of stress. PMID:21655957

  10. 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

  11. Membrane transporters and carbon metabolism implicated in chloride homeostasis differentiate salt stress responses in tolerant and sensitive Citrus rootstocks.

    PubMed

    Brumós, Javier; Colmenero-Flores, José M; Conesa, Ana; Izquierdo, Pedro; Sánchez, Guadalupe; Iglesias, Domingo J; López-Climent, María F; Gómez-Cadenas, Aurelio; Talón, Manuel

    2009-08-01

    Salinity tolerance in Citrus is strongly related to leaf chloride accumulation. Both chloride homeostasis and specific genetic responses to Cl(-) toxicity are issues scarcely investigated in plants. To discriminate the transcriptomic network related to Cl(-) toxicity and salinity tolerance, we have used two Cl(-) salt treatments (NaCl and KCl) to perform a comparative microarray approach on two Citrus genotypes, the salt-sensitive Carrizo citrange, a poor Cl(-) excluder, and the tolerant Cleopatra mandarin, an efficient Cl(-) excluder. The data indicated that Cl(-) toxicity, rather than Na(+) toxicity and/or the concomitant osmotic perturbation, is the primary factor involved in the molecular responses of citrus plant leaves to salinity. A number of uncharacterized membrane transporter genes, like NRT1-2, were differentially regulated in the tolerant and the sensitive genotypes, suggesting its potential implication in Cl(-) homeostasis. Analyses of enriched functional categories showed that the tolerant rootstock induced wider stress responses in gene expression while repressing central metabolic processes such as photosynthesis and carbon utilization. These features were in agreement with phenotypic changes in the patterns of photosynthesis, transpiration, and stomatal conductance and support the concept that regulation of transpiration and its associated metabolic adjustments configure an adaptive response to salinity that reduces Cl(-) accumulation in the tolerant genotype. PMID:19190944

  12. Salt tolerance function of the novel C2H2-type zinc finger protein TaZNF in wheat.

    PubMed

    Ma, Xiaoli; Liang, Wenji; Gu, Peihan; Huang, Zhanjing

    2016-09-01

    The expression profile chip of the wheat salt-tolerant mutant RH8706-49 was investigated under salt stress in our laboratory. Results revealed a novel gene induced by salt stress with unknown functions. The gene was named as TaZNF (Triticum aestivum predicted Dof zinc finger protein) because it contains the zf-Dof superfamily and was deposited in GenBank (accession no. KF307327). Further analysis showed that TaZNF significantly improved the salt-tolerance of transgenic Arabidopsis. Various physiological indices of the transgenic plant were improved compared with those of the control after salt stress. Non-invasive micro-test (NMT) detection showed that the root tip of transgenic Arabidopsis significantly expressed Na(+) excretion. TaZNF is mainly localized in the nucleus and exhibited transcriptional activity. Hence, this protein was considered a transcription factor. The TaZNF upstream promoter was then cloned and was found to contain three salts, one jasmonic acid methyl ester (MeJA), and several ABA-responsive elements. The GUS staining and quantitative results of different tissues in the full-length promoter in the transgenic plants showed that the promoter was not tissue specific. The promoter activity in the root, leaf, and flower was enhanced after induction by salt stress. Moreover, GUS staining and quantitative measurement of GUS activity showed that the promoter sequence contained the positive regulatory element of salt and MeJA after their respective elements were mutated in the full-length promoter. RNA-Seq result showed that 2727 genes were differentially expressed; most of these genes were involved in the metabolic pathway and biosynthesis of secondary metabolite pathway. PMID:27156137

  13. Halopriming mediated salt and iso-osmotic PEG stress tolerance and, gene expression profiling in sugarcane (Saccharum officinarum L.).

    PubMed

    Patade, Vikas Yadav; Bhargava, Sujata; Suprasanna, Penna

    2012-10-01

    Seed priming is a well known pre-germination strategy that improves seed performance. However, biochemical and molecular mechanisms underlying priming mediated stress tolerance are little understood. Here, we report results of the study on growth, physiological characteristics and expression of stress responsive genes in salt primed sugarcane cv. Co 86032 plants in response to salt (NaCl, 150 mM) or iso-osmotic (-0.7 MPa) polyethylene glycol-PEG 8000 (20 % w/v) stress exposure for 15 days. Variable growth, osmolyte accumulation and antioxidant capacity was revealed among the primed and non-primed plants. The primed plants showed better tolerance to the salt or PEG stress, as revealed by better growth and lower membrane damage, through better antioxidant capacity as compared to the respective non-primed controls. Further, steady state transcript expression analysis revealed up regulation of sodium proton antiporter (NHX) while, down regulation of sucrose transporter (SUT1), delta ( 1 )-pyrolline-5-carboxylate synthetase (P5CS) and proline dehydrogenase (PDH) in primed plants on exposure to the stress as compared to the non-primed plants. Transcript abundance of catalase (CAT2) decreased by about 25 % in leaves of non-primed stressed plants, however, the expression was maintained in leaves of the stressed primed plants to that of non-stressed controls. Thus, the results indicated priming mediated salt and PEG stress tolerance through altered gene expression leading to improved antioxidant capacity in sugarcane. PMID:22740137

  14. Functional analyses of a putative plasma membrane Na+/H+ antiporter gene isolated from salt tolerant Helianthus tuberosus.

    PubMed

    Li, Qing; Tang, Zhong; Hu, Yibing; Yu, Ling; Liu, Zhaopu; Xu, Guohua

    2014-08-01

    Jerusalem artichokes (Helianthus tuberosus L.) can tolerate relatively higher salinity, drought and heat stress. In this paper, we report the cloning of a Salt Overly Sensitive 1 (SOS1) gene encoding a plasma membrane Na(+)/H(+) antiporter from a highly salt-tolerant genotype of H. tuberosus, NY1, named HtSOS1 and characterization of its function in yeast and rice. The amino acid sequence of HtSOS1 showed 83.4% identity with the previously isolated SOS1 gene from the Chrysanthemum crassum. The mRNA level in the leaves of H. tuberosus was significantly up-regulated by presence of high concentrations of NaCl. Localization analysis using rice protoplast expression showed that the protein encoded by HtSOS1 was located in the plasma membrane. HtSOS1 partially suppressed the salt sensitive phenotypes of a salt sensitive yeast strain. In comparison with wild type (Oryza sativa L., ssp. Japonica. cv. Nipponbare), the transgenic rice expressed with HtSOS1 could exclude more Na(+) and accumulate more K(+). Expression of HtSOS1 decreased Na(+) content much larger in the shoot than in the roots, resulting in more water content in the transgenic rice than WT. These data suggested that HtSOS1 may be useful in transgenic approaches to improving the salinity tolerance of glycophyte. PMID:24771143

  15. 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

  16. 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

  17. 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.

  18. Generation of Wheat Transcription Factor FOX Rice Lines and Systematic Screening for Salt and Osmotic Stress Tolerance

    PubMed Central

    Zhang, Qian; Liu, Yayun; Zhu, Butuo; Cao, Jian; Li, Zhanpeng; Han, Longzhi; Jia, Jizeng; Zhao, Guangyao; Sun, Xuehui

    2015-01-01

    Transcription factors (TFs) play important roles in plant growth, development, and responses to environmental stress. In this study, we collected 1,455 full-length (FL) cDNAs of TFs, representing 45 families, from wheat and its relatives Triticum urartu, Aegilops speltoides, Aegilops tauschii, Triticum carthlicum, and Triticum aestivum. More than 15,000 T0 TF FOX (Full-length cDNA Over-eXpressing) rice lines were generated; of these, 10,496 lines set seeds. About 14.88% of the T0 plants showed obvious phenotypic changes. T1 lines (5,232 lines) were screened for salt and osmotic stress tolerance using 150 mM NaCl and 20% (v/v) PEG-4000, respectively. Among them, five lines (591, 746, 1647, 1812, and J4065) showed enhanced salt stress tolerance, five lines (591, 746, 898, 1078, and 1647) showed enhanced osmotic stress tolerance, and three lines (591, 746, and 1647) showed both salt and osmotic stress tolerance. Further analysis of the T-DNA flanking sequences showed that line 746 over-expressed TaEREB1, line 898 over-expressed TabZIPD, and lines 1812 and J4065 over-expressed TaOBF1a and TaOBF1b, respectively. The enhanced salt and osmotic stress tolerance of lines 898 and 1812 was confirmed by retransformation of the respective genes. Our results demonstrate that a heterologous FOX system may be used as an alternative genetic resource for the systematic functional analysis of the wheat genome. PMID:26176782

  19. Screening for Abiotic Stress Tolerance in Rice: Salt, Cold, and Drought.

    PubMed

    Almeida, Diego M; Almadanim, M Cecília; Lourenço, Tiago; Abreu, Isabel A; Saibo, Nelson J M; Oliveira, M Margarida

    2016-01-01

    Rice (Oryza sativa) is the primary source of food for more than half of the world population. Most rice varieties are severely injured by abiotic stresses, with strong social and economic impact. Understanding rice responses to stress may help breeding for more tolerant varieties. However, papers dealing with stress experiments often describe very different experimental designs, thus making comparisons difficult. The use of identical setups is the only way to generate comparable data. This chapter is organized into three sections, describing the experimental conditions established at the Genomics of Plant Stress (GPlantS) unit of ITQB to assess the response of rice plants to three different abiotic stresses--high salinity, cold stress, and drought. All sections include a detailed description of the materials and methodology, as well as useful notes gathered from the GPlantS team's experience. We use rice seedlings as plants at this stage show high sensitivity to abiotic stresses. For the salt and cold stress assays we use hydroponic cultures, while for the drought assay plants are grown in soil and subjected to water withholding. All setups enable visual score determination and are suitable for sample collection along the imposition of stress. The proposed methodologies are simple and affordable to implement in most labs, allowing the discrimination of several rice genotypes at the molecular and phenotypic level. PMID:26867623

  20. 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

  1. Identification of Chimeric Repressors that Confer Salt and Osmotic Stress Tolerance in Arabidopsis

    PubMed Central

    Kazama, Daisuke; Itakura, Masateru; Kurusu, Takamitsu; Mitsuda, Nobutaka; Ohme-Takagi, Masaru; Tada, Yuichi

    2013-01-01

    We produced transgenic Arabidopsis plants that express chimeric genes for transcription factors converted to dominant repressors, using Chimeric REpressor gene-Silencing Technology (CRES-T), and evaluated the salt tolerance of each line. The seeds of the CRES-T lines for ADA2b, Msantd, DDF1, DREB26, AtGeBP, and ATHB23 exhibited higher germination rates than Wild type (WT) and developed rosette plants under up to 200 mM NaCl or 400 mM mannitol. WT plants did not grow under these conditions. In these CRES-T lines, the expression patterns of stress-related genes such as RD29A, RD22, DREB1A, and P5CS differed from those in WT plants, suggesting the involvement of the six transcription factors identified here in the stress response pathways regulated by the products of these stress-related genes. Our results demonstrate additional proof that CRES-T is a superior tool for revealing the function of transcription factors. PMID:27137403

  2. Identification and characterization of a novel salt-tolerant esterase from a Tibetan glacier metagenomic library.

    PubMed

    De Santi, Concetta; Ambrosino, Luca; Tedesco, Pietro; Zhai, Lei; Zhou, Cheng; Xue, Yanfen; Ma, Yanhe; de Pascale, Donatella

    2015-01-01

    A salt-tolerant esterase, designated H9Est, was identified from a metagenomic library of the Karuola glacier. H9Est gene comprised 1071 bp and encoded a polypeptide of 357 amino acids with a molecular mass of 40 kDa. Sequence analysis revealed that H9Est belonged to the family IV of bacterial lypolitic enzyme. H9Est was overexpressed in Escherichia coli and the purified enzyme showed hydrolytic activity towards p-nitrophenyl esters with carbon chain from 2 to 8. The optimal esterase activity was at 40°C and pH 8.0 and the enzyme retained its activity towards some miscible organic solvents such as polyethylene glycol. A three-dimensional model of H9Est revealed that S200, D294, and H324 formed the H9Est catalytic triad. Circular Dichroism spectra and molecular dynamic simulation indicated that the esterase had a wide denaturation temperature range and flexible loops that would be beneficial for H9Est performance at low temperatures while retaining heat-resistant features. PMID:25920073

  3. The evolutionary origin of CIPK16: A gene involved in enhanced salt tolerance.

    PubMed

    Amarasinghe, Shanika; Watson-Haigh, Nathan S; Gilliham, Matthew; Roy, Stuart; Baumann, Ute

    2016-07-01

    Calcineurin B-like protein interacting protein kinases (CIPKs) are key regulators of pre-transcriptional and post-translational responses to abiotic stress. Arabidopsis thaliana CIPK16 (AtCIPK16) was identified from a forward genetic screen as a gene that mediates lower shoot salt accumulation and improved salinity tolerance in Arabidopsis and transgenic barley. Here, we aimed to gain an understanding of the evolution of AtCIPK16, and orthologues of CIPK16 in other plant species including barley, by conducting a phylogenetic analysis of terrestrial plant species. The resulting protein sequence based phylogenetic trees revealed a single clade that included AtCIPK16 along with two segmentally duplicated CIPKs, AtCIPK5 and AtCIPK25. No monocots had proteins that fell into this clade; instead the most closely related monocot proteins formed a group basal to the entire CIPK16, 5 and 25 clade. We also found that AtCIPK16 contains a core Brassicales specific indel and a putative nuclear localisation signal, which are synapomorphic characters of CIPK16 genes. In addition, we present a model that proposes the evolution of CIPK16, 5 and 25 clade. PMID:27044608

  4. Improving the yield of (+)-terrein from the salt-tolerant Aspergillus terreus PT06-2.

    PubMed

    Zhao, Chengying; Guo, Lei; Wang, Liping; Zhu, Guoliang; Zhu, Weiming

    2016-05-01

    (+)-Terrein has a potential application for drug discovery. To improve the yield of (+)-terrein, two-level Plackett-Burman design and response surface methodology methods were used to optimize the condition of a salt-tolerant fungus, Aspergillus terreus PT06-2. As a result, the yield of (+)-terrein reached 8.20 ± 0.072 g/L in a 500-mL flask containing 150 mL optimal medium consisted of 13.1 % NaCl, 3.6 % starch, 2 % sodium glutamate, 0.05 % KCl, 3 % inoculum size, adjusting initial pH value to 5 with 10 % HCl and shaking for 18 days at 28 °C and 180 rpm. The production of (+)-terrein was 47.0 % higher than the highest production reported in shake flasks. The advantages of this optimization are uses of single carbon source and nitrogen source and easy separation and purification by recrystallization. The result exhibited the potential and advantages of A. terreus PT06-2 in industrial production of (+)-terrein by fermentation. PMID:27038947

  5. Transcriptome Analyses of a Salt-Tolerant Cytokinin-Deficient Mutant Reveal Differential Regulation of Salt Stress Response by Cytokinin Deficiency

    PubMed Central

    Nishiyama, Rie; Le, Dung Tien; Watanabe, Yasuko; Matsui, Akihiro; Tanaka, Maho; Seki, Motoaki; Yamaguchi-Shinozaki, Kazuko; Shinozaki, Kazuo; Tran, Lam-Son Phan

    2012-01-01

    Soil destruction by abiotic environmental conditions, such as high salinity, has resulted in dramatic losses of arable land, giving rise to the need of studying mechanisms of plant adaptation to salt stress aimed at creating salt-tolerant plants. Recently, it has been reported that cytokinins (CKs) regulate plant environmental stress responses through two-component systems. A decrease in endogenous CK levels could enhance salt and drought stress tolerance. Here, we have investigated the global transcriptional change caused by a reduction in endogenous CK content under both normal and salt stress conditions. Ten-day-old Arabidopsis thaliana wild-type (WT) and CK-deficient ipt1,3,5,7 plants were transferred to agar plates containing either 0 mM (control) or 200 mM NaCl and maintained at normal growth conditions for 24 h. Our experimental design allowed us to compare transcriptome changes under four conditions: WT-200 mM vs. WT-0 mM, ipt1,3,5,7-0 mM vs. WT-0 mM, ipt1,3,5,7-200 mM vs. ipt1,3,5,7-0 mM and ipt1,3,5,7-200 mM vs. WT-200 mM NaCl. Our results indicated that the expression of more than 10% of all of the annotated Arabidopsis genes was altered by CK deficiency under either normal or salt stress conditions when compared to WT. We found that upregulated expression of many genes encoding either regulatory proteins, such as NAC, DREB and ZFHD transcription factors and the calcium sensor SOS3, or functional proteins, such as late embryogenesis-abundant proteins, xyloglucan endo-transglycosylases, glycosyltransferases, glycoside hydrolases, defensins and glyoxalase I family proteins, may contribute to improved salt tolerance of CK-deficient plants. We also demonstrated that the downregulation of photosynthesis-related genes and the upregulation of several NAC genes may cause the altered morphological phenotype of CK-deficient plants. This study highlights the impact of CK regulation on the well-known stress-responsive signaling pathways, which regulate plant

  6. A novel bioremediation strategy for petroleum hydrocarbon pollutants using salt tolerant Corynebacterium variabile HRJ4 and biochar.

    PubMed

    Zhang, Hairong; Tang, Jingchun; Wang, Lin; Liu, Juncheng; Gurav, Ranjit Gajanan; Sun, Kejing

    2016-09-01

    The present work aimed to develop a novel strategy to bioremediate the petroleum hydrocarbon contaminants in the environment. Salt tolerant bacterium was isolated from Dagang oilfield, China and identified as Corynebacterium variabile HRJ4 based on 16S rRNA gene sequence analysis. The bacterium had a high salt tolerant capability and biochar was developed as carrier for the bacterium. The bacteria with biochar were most effective in degradation of n-alkanes (C16, C18, C19, C26, C28) and polycyclic aromatic hydrocarbons (NAP, PYR) mixture. The result demonstrated that immobilization of C. variabile HRJ4 with biochar showed higher degradation of total petroleum hydrocarbons (THPs) up to 78.9% after 7-day of incubation as compared to the free leaving bacteria. The approach of this study will be helpful in clean-up of petroleum-contamination in the environments through bioremediation process using eco-friendly and cost effective materials like biochar. PMID:27593267

  7. 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

  8. 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

  9. 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

  10. Ectopic expression of Arabidopsis thaliana Na+(K+)/H+ antiporter gene, AtNHX5, enhances soybean salt tolerance.

    PubMed

    Wu, X X; Li, J; Wu, X D; Liu, Q; Wang, Z K; Liu, S S; Li, S N; Ma, Y L; Sun, J; Zhao, L; Li, H Y; Li, D M; Li, W B; Su, A Y

    2016-01-01

    Drought and salt stresses are the two major factors influencing the yield and quality of crops worldwide. Na(+)(K(+))/H(+) antiporters (NHXs) are ubiquitous membrane proteins that play important roles in maintaining the cellular pH and Na(+)(K(+)) homeostasis. The model plant Arabidopsis potentially encodes six NHX genes, namely AtNHX1 to 6. In the present study, AtNHX5, a comparatively less well-studied NHX, was cloned and transferred into a soybean variety, Dongnong-50, via Agrobacterium-mediated cotyledonary node transformation to assess its role in improving salt tolerance of the transgenic plants. The transgenic soybean plants were tolerant to the presence of 300 mM NaCl whereas the non-transgenic plants were not. Furthermore, after NaCl treatment, the transgenic plants had a higher content of free proline but lower content of malondialdehyde compared to the non-transgenic plants. Our results revealed that that AtNHX5 possibly functioned by efficiently transporting Na(+) and K(+) ions from the roots to the leaves. Overall, the results obtained in this study suggest that soybean salt tolerance could be improved through the over expression of Arabidopsis AtNHX5. PMID:27323012

  11. Regulation of the Potassium to Sodium Ratio and of the Osmotic Potential in Relation to Salt Tolerance in Yeasts

    PubMed Central

    Norkrans, Birgitta; Kylin, Anders

    1969-01-01

    By using the isotope pairs 22Na-24Na and 42K-86Rb, the uptake and retention of Na and K was studied in the salt-tolerant Debaryomyces hansenii and in the less tolerant Saccharomyces cerevisiae at NaCl levels of 4 mm and 0.68, 1.35, and 2.7 m in the medium. The ratio of K to Na is much higher in the cells than in the media, and higher in D. hansenii than in S. cerevisiae under comparable conditions. The difference between the two species is due to a better Na extrusion and a better uptake of K in D. hansenii. The kinetics of ion transport show that at about the time when extrusion of Na could be demonstrated in D. hansenii, K-Rb previously lost to an easily washable compartment of the cells was reabsorbed in both organisms. More H+ was given off from S. cerevisiae than from D. hansenii in the course of these events. The findings fit the working hypothesis tested, which regards salt tolerance as partly dependent on the ability to mobilize energy to extrude Na from the cells and to take up K. The volume changes in S. cerevisiae are greater and are more slowly overcome than those in D. hansenii. The total salt level of the cells is not sufficient to counteract the osmotic potential of the medium, so that additional osmoregulatory mechanisms must be involved in determining halotolerance. PMID:5354950

  12. Salt tolerance underlies the cryptic invasion of North American salt marshes by an introduced haplotype of the common reed Phragmites australis (Poaceae)

    USGS Publications Warehouse

    Vasquez, E.A.; Glenn, E.P.; Brown, J.J.; Guntenspergen, G.R.; Nelson, S.G.

    2005-01-01

    A distinct, non-native haplotype of the common reed Phragmites australis has become invasive in Atlantic coastal Spartina marshes. We compared the salt tolerance and other growth characteristics of the invasive M haplotype with 2 native haplotypes (F and AC) in greenhouse experiments. The M haplotype retained 50% of its growth potential up to 0.4 M NaCl, whereas the F and AC haplotypes did not grow above 0.1 M NaCl. The M haplotype produced more shoots per gram of rhizome tissue and had higher relative growth rates than the native haplotypes on both freshwater and saline water treatments. The M haplotype also differed from the native haplotypes in shoot water content and the biometrics of shoots and rhizomes. The results offer an explanation for how the M haplotype is able to spread in coastal salt marshes and support the conclusion of DNA analyses that the M haplotype is a distinct ecotype of P. australis.

  13. Ectopic overexpression of the aldehyde dehydrogenase ALDH21 from Syntrichia caninervis in tobacco confers salt and drought stress tolerance.

    PubMed

    Yang, Honglan; Zhang, Daoyuan; Li, Haiyan; Dong, Lingfeng; Lan, Haiyan

    2015-10-01

    Aldehyde dehydrogenases are important enzymes that play vital roles in mitigating oxidative/electrophilic stress when plants are exposed to environmental stress. An aldehyde dehydrogenase gene from Syntrichia caninervis, ScALDH21, was introduced into tobacco using Agrobacterium-mediated transformation to generate ScALDH21-overexpressing tobacco plants to investigate its effect on drought and salt resistance. Detached leaves from ScALDH21-overexpressing tobacco plants showed less water loss than those from nontransgenic plants. When subjected to drought and salt stress, transgenic plants displayed higher germination ratios, higher root lengths, greater fresh weight, higher proline accumulation, lower malondialdehyde (MDA) contents and stronger photosynthetic capacities, as well as higher activities of antioxidant enzymes, i.e., superoxide dismutase, catalase and peroxidase, compared with control plants. Therefore, ScALDH21 overexpression in transgenic tobacco plants can enhance drought and salt tolerance and can be used as a candidate gene for the molecular breeding of salt- and drought-tolerant plants. PMID:26202169

  14. CYP709B3, a cytochrome P450 monooxygenase gene involved in salt tolerance in Arabidopsis thaliana

    PubMed Central

    2013-01-01

    Background Within the Arabidopsis genome, there are 272 cytochrome P450 monooxygenase (P450) genes. However, the biological functions of the majority of these P450s remain unknown. The CYP709B family of P450s includes three gene members, CYP709B1, CYP709B2 and CYP709B3, which have high amino acid sequence similarity and lack reports elucidating biological functions. Results We identified T-DNA insertion-based null mutants of the CYP709B subfamily of genes. No obvious morphological phenotypes were exhibited under normal growth conditions. When the responses to ABA and salt stress were studied in these mutants, only the cyp709b3 mutant showed sensitivity to ABA and salt during germination. Under moderate salt treatment (150 mM NaCl), cyp709b3 showed a higher percentage of damaged seedlings, indicating a lower tolerance to salt stress. CYP709B3 was highly expressed in all analyzed tissues and especially high in seedlings and leaves. In contrast, CYP709B1 and CYP709B2 were highly expressed in siliques, but were at very low levels in other tissues. Under salt stress condition, CYP709B3 gene expression was induced after 24 hr and remained at high expression level. Expression of the wild type CYP709B3 gene in the cyp709b3 mutant fully complemented the salt intolerant phenotype. Furthermore, metabolite profiling analysis revealed some differences between wild type and cyp709b3 mutant plants, supporting the salt intolerance phenotype of the cyp709b3 mutant. Conclusions These results suggest that CYP709B3 plays a role in ABA and salt stress response and provides evidence to support the functions of cytochrome P450 enzymes in plant stress response. PMID:24164720

  15. Bioavailability, food effect and tolerability of S-naproxen betainate sodium salt monohydrate in steady state.

    PubMed

    Marzo, A; Dal Bo, L; Wool, C; Cerutti, R

    1998-09-01

    S-Naproxen betainate sodium salt monohydrate (naproxen-beta Na, CAS 104124-26-7, Aprenin) in 550 mg capsules (corresponding to 327 mg of naproxen) was administered to 24 healthy volunteers (12 males and 12 females) b.i.d. to steady state in order to check its bioavailability, food interaction and tolerability. Plasma concentrations of naproxen were measured by a well validated HPLC method with fluorimetric detection as a morning pre-dose on days 1 to 6 and in timed samples in three different situations, as follows: a) after the morning dose on day 7 in a fasting status, b) after the evening dose and dinner on day 7 and c) after the morning dose of day 8, taken after a high-fat content breakfast. Pharmacokinetic parameters were evaluated from plasma concentrations by non-compartmental analysis to describe the above three situations. The steady state was reached early, namely by the second day of treatment. The extent of absorption did not differ in the three situations tested, whereas the rate of absorption was fastest in fasting conditions, lowest with the evening dose and intermediate after the high-fat content breakfast. The slow absorption rate of the evening dose was attributed to a circadian rhythm and should allow therapeutically active levels early in the morning, when arthritis pain is particularly tedious. In the three situations explored Cmax, Cmin and AUC were associated with CV % values ranging from 11.7 to 17.2%, which are very low and rare in pharmacokinetic trials. This low variability should allow an accurate estimate of the therapeutic effect expected. Tolerability was checked by objective and subjective symptoms, including vital signs, blood/urine biochemical parameters and occult blood in stools, and proved to be very good. From the comparison of these data with those previously published by other authors who have administered 500 mg of naproxen b.i.d., pre-dose concentrations in a steady state proved to be similar, despite the different doses

  16. 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

  17. Responses of tolerant and susceptible Kentucky bluegrass (Poa pratensis L.) germplasm to salt stress

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Much of semi-arid western North America is salt-affected, and utilizing turfgrasses in salty areas can be challenging. Kentucky bluegrass is relatively susceptible to salt stress, showing reduced growth, osmotic and ionic stress, and eventual death at moderate or high salt concentrations. Consider...

  18. Pathway analysis of the transcriptome and metabolome of salt sensitive and tolerant poplar species reveals evolutionary adaption of stress tolerance mechanisms

    PubMed Central

    2010-01-01

    Background Populus euphratica is a salt tolerant and Populus × canescens a salt sensitive poplar species. Because of low transcriptional responsiveness of P. euphratica to salinity we hypothesized that this species exhibits an innate activation of stress protective genes compared with salt sensitive poplars. To test this hypothesis, the transcriptome and metabolome of mature unstressed leaves of P. euphratica and P. × canescens were compared by whole genome microarray analyses and FT-ICR-MS metabolite profiling. Results Direct cross-species comparison of the transcriptomes of the two poplar species from phylogenetically different sections required filtering of the data set. Genes assigned to the GO slim categories 'mitochondria', 'cell wall', 'transport', 'energy metabolism' and 'secondary metabolism' were significantly enriched, whereas genes in the categories 'nucleus', 'RNA or DNA binding', 'kinase activity' and 'transcription factor activity' were significantly depleted in P. euphratica compared with P. × canescens. Evidence for a general activation of stress relevant genes in P. euphratica was not detected. Pathway analyses of metabolome and transcriptome data indicated stronger accumulation of primary sugars, activation of pathways for sugar alcohol production, and faster consumption of secondary metabolites in P. euphratica compared to P. × canescens. Physiological measurements showing higher respiration, higher tannin and soluble phenolic contents as well as enrichment of glucose and fructose in P. euphratica compared to P. × canescens corroborated the results of pathway analyses. Conclusion P. euphratica does not rely on general over-expression of stress pathways to tolerate salt stress. Instead, it exhibits permanent activation of control mechanisms for osmotic adjustment (sugar and sugar alcohols), ion compartmentalization (sodium, potassium and other metabolite transporters) and detoxification of reactive oxygen species (phenolic compounds). The

  19. 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

  20. 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

  1. Great Salt Lake halophilic microorganisms as models for astrobiology: evidence for desiccation tolerance and ultraviolet irradiation resistance

    NASA Astrophysics Data System (ADS)

    Baxter, Bonnie K.; Eddington, Breanne; Riddle, Misty R.; Webster, Tabitha N.; Avery, Brian J.

    2007-09-01

    Great Salt Lake (GSL) is home to halophiles, salt-tolerant Bacteria and Archaea, which live at 2-5M NaCl. In addition to salt tolerance, GSL halophiles exhibit resistance to both ultraviolet (UV) irradiation and desiccation. First, to understand desiccation resistance, we sought to determine the diversity of GSL halophiles capable of surviving desiccation in either recently formed GSL halite crystals or GSL Artemia (brine shrimp) cysts. From these desiccated environments, surviving microorganisms were cultured and isolated, and genomic DNA was extracted from the individual species for identification by 16S rRNA gene homology. From the surface-sterilized cysts we also extracted DNA of the whole microbial population for non-cultivation techniques. We amplified the archaeal or bacterial 16S rRNA gene from all genomic DNA, cloned the cyst population amplicons, and sequenced. These sequences were compared to gene databases for determination of closest matched species. Interestingly, the isolates from the crystal dissolution are distinct from those previously isolated from GSL brine. The cyst population results reveal species not found in crystals or brine, and may indicate microorganisms that live as endosymbionts of this hypersaline arthropod. Second, we explored UV resistance in a GSL haloarchaea species, "H. salsolis." This strain resists UV irradiation an order of magnitude better than control species, all of which have intact repair systems. To test the hypothesis that halophiles have a photoprotection system, which prevents DNA damage from occurring, we designed an immunoassay to detect thymine dimers following UV irradiation. "H. salsolis" showed remarkable resistance to dimer formation. Evidence for both UV and desiccation resistance in these salt-tolerant GSL halophiles makes them well-suited as models for Astrobiological studies in pursuit of questions about life beyond earth.

  2. Genome-Wide Association Study Identifies Loci for Salt Tolerance during Germination in Autotetraploid Alfalfa (Medicargo sativa L.) using Genotyping by Sequencing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    : In this study, we used a diverse panel of alfalfa accessions to identify molecular markers associated with salt tolerance during germination by genome-wide association (GWA) mapping and genotyping-by-sequencing (GBS). Three levels of salt treatments were applied during seed germination. Phenotypic...

  3. Regulated AtHKT1 Gene Expression by a Distal Enhancer Element and DNA Methylation in the Promoter Plays an Important Role in Salt Tolerance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Arabidopsis thaliana High-affinityK+ Transporter 1 (AtHKT1, At4g10310) is a crucial salt tolerance determinant, but its molecular mechanisms for Na+ uptake and transport in whole plant level still remains elusive. Through sos3 (salt overly sensitive 3) suppressors screening, two allelic suppress...

  4. 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

  5. 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

  6. 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

  7. Cloning of the Lycopene β-cyclase Gene in Nicotiana tabacum and Its Overexpression Confers Salt and Drought Tolerance

    PubMed Central

    Shi, Yanmei; Guo, Jinggong; Zhang, Wei; Jin, Lifeng; Liu, Pingping; Chen, Xia; Li, Feng; Wei, Pan; Li, Zefeng; Li, Wenzheng; Wei, Chunyang; Zheng, Qingxia; Chen, Qiansi; Zhang, Jianfeng; Lin, Fucheng; Qu, Lingbo; Snyder, John Hugh; Wang, Ran

    2015-01-01

    Carotenoids are important pigments in plants that play crucial roles in plant growth and in plant responses to environmental stress. Lycopene β cyclase (β-LCY) functions at the branch point of the carotenoid biosynthesis pathway, catalyzing the cyclization of lycopene. Here, a β-LCY gene from Nicotiana tabacum, designated as Ntβ-LCY1, was cloned and functionally characterized. Robust expression of Ntβ-LCY1 was found in leaves, and Ntβ-LCY1 expression was obviously induced by salt, drought, and exogenous abscisic acid treatments. Strong accumulation of carotenoids and expression of carotenoid biosynthesis genes resulted from Ntβ-LCY1 overexpression. Additionally, compared to wild-type plants, transgenic plants with overexpression showed enhanced tolerance to salt and drought stress with higher abscisic acid levels and lower levels of malondialdehyde and reactive oxygen species. Conversely, transgenic RNA interference plants had a clear albino phenotype in leaves, and some plants did not survive beyond the early developmental stages. The suppression of Ntβ-LCY1 expression led to lower expression levels of genes in the carotenoid biosynthesis pathway and to reduced accumulation of carotenoids, chlorophyll, and abscisic acid. These results indicate that Ntβ-LCY1 is not only a likely cyclization enzyme involved in carotenoid accumulation but also confers salt and drought stress tolerance in Nicotiana tabacum. PMID:26703579

  8. Cloning and characterization of two thermo- and salt-tolerant oligoalginate lyases from marine bacterium Halomonas sp.

    PubMed

    Yang, Xuemei; Li, Shangyong; Wu, Ying; Yu, Wengong; Han, Feng

    2016-05-01

    Two new alginate lyase genes, oalY1 and oalY2, have been cloned from the newly isolated marine bacterium Halomonas sp. QY114 and expressed in Escherichia coli The deduced alginate lyases, OalY1 and OalY2, belonged to polysaccharide lyase (PL) family 17 and showed less than 45% amino acid identity with all of the characterized oligoalginate lyases. OalY1 and OalY2 exhibited the highest activities at 45°C and 50°C, respectively. Both of them showed more than 50% of the highest activity at 60°C, and 20% at 80°C. In addition, they were salt-dependent and salt-tolerant since both of them showed the highest activity in the presence of 0.5 M NaCl and preserved 63% and 68% of activity in the presence of 3 M NaCl. Significantly, OalY1 and OalY2 could degrade both polyM and polyG blocks into alginate monosaccharides in an exo-lytic type, indicating that they are bifunctional alginate lyases. In conclusion, our study indicated that OalY1 and OalY2 are good candidates for alginate saccharification application, and the salt-tolerance may present an exciting new concept for biofuel production from native brown seaweeds. PMID:27030725

  9. Cloning of the Lycopene β-cyclase Gene in Nicotiana tabacum and Its Overexpression Confers Salt and Drought Tolerance.

    PubMed

    Shi, Yanmei; Guo, Jinggong; Zhang, Wei; Jin, Lifeng; Liu, Pingping; Chen, Xia; Li, Feng; Wei, Pan; Li, Zefeng; Li, Wenzheng; Wei, Chunyang; Zheng, Qingxia; Chen, Qiansi; Zhang, Jianfeng; Lin, Fucheng; Qu, Lingbo; Snyder, John Hugh; Wang, Ran

    2015-01-01

    Carotenoids are important pigments in plants that play crucial roles in plant growth and in plant responses to environmental stress. Lycopene β cyclase (β-LCY) functions at the branch point of the carotenoid biosynthesis pathway, catalyzing the cyclization of lycopene. Here, a β-LCY gene from Nicotiana tabacum, designated as Ntβ-LCY1, was cloned and functionally characterized. Robust expression of Ntβ-LCY1 was found in leaves, and Ntβ-LCY1 expression was obviously induced by salt, drought, and exogenous abscisic acid treatments. Strong accumulation of carotenoids and expression of carotenoid biosynthesis genes resulted from Ntβ-LCY1 overexpression. Additionally, compared to wild-type plants, transgenic plants with overexpression showed enhanced tolerance to salt and drought stress with higher abscisic acid levels and lower levels of malondialdehyde and reactive oxygen species. Conversely, transgenic RNA interference plants had a clear albino phenotype in leaves, and some plants did not survive beyond the early developmental stages. The suppression of Ntβ-LCY1 expression led to lower expression levels of genes in the carotenoid biosynthesis pathway and to reduced accumulation of carotenoids, chlorophyll, and abscisic acid. These results indicate that Ntβ-LCY1 is not only a likely cyclization enzyme involved in carotenoid accumulation but also confers salt and drought stress tolerance in Nicotiana tabacum. PMID:26703579

  10. 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

  11. Plant regeneration from immature inflorescence derived callus cultures of salt tolerant kallar grass (Leptochloa fusca L.).

    PubMed

    Praveena, M; Giri, C C

    2012-10-01

    Efficient plant regeneration has been achieved from immature inflorescence derived callus cultures of salt tolerant grass Leptochloa fusca (L.). Young inflorescence explants displayed wide-ranging responses for callus induction and plant regeneration when subjected to different cold treatment durations and without cold treatment exposure (control) prior to its inoculation to MS medium supplemented with different concentrations/combinations of plant growth regulators (PGRs). The PGRs included auxins: 2, 4-dichlorophenoxy acetic acid (2, 4-D), picloram (Pic), 3, 6-dichloro-2-methoxy benzoic acid (dicamba) and cytokinins: Kinetin (KN), N6-benzyl adenine (BA). These treatments promoted different callus induction frequencies as well as various callus types such as type 1, type 2 and type 3. Induction of type 2 callus (white and compact) with potential for regeneration was obtained from cold treated (3 days at 10 °C) immature inflorescence cultured on MS medium containing 2.0 mg/l dicamba and 0.25 mg/l BA. The study demonstrated that 2.0 mg/l dicamba and 0.25 mg/l BA induced callus promoted improved frequency compared to zilch shoot regeneration response with other combinations involving 2, 4-D, picloram, KN and BA. Full strength MS supplemented with 2.0 mg/l NAA and 0.5 mg/l BA was found to be optimal for plant regeneration. The regeneration frequencies ranged from 13.8 ± 1.366 to 55.5 ± 2.766 with highest number of shoots (19.1 ± 0.560) per 50-60 mg of callus as explants after 28 days of inoculation. Plant regeneration was also obtained on the dicamba callus induction medium itself within 21 days inoculation of immature inflorescence explants. Half strength MS medium both semisolid and liquid devoid of plant growth regulators promoted highest frequency (92.8 ± 4.099 and 100 ± 0.00) of rooting in regenerated shoots. Plants with well developed roots were successfully transferred to pots and grown to maturity with normal flowering and

  12. Co-overexpressing a Plasma Membrane and a Vacuolar Membrane Sodium/Proton Antiporter Significantly Improves Salt Tolerance in Transgenic Arabidopsis Plants

    PubMed Central

    Pehlivan, Necla; Sun, Li; Jarrett, Philip; Yang, Xiaojie; Mishra, Neelam; Chen, Lin; Kadioglu, Asim; Shen, Guoxin; Zhang, Hong

    2016-01-01

    The Arabidopsis gene AtNHX1 encodes a vacuolar membrane-bound sodium/proton (Na+/H+) antiporter that transports Na+ into the vacuole and exports H+ into the cytoplasm. The Arabidopsis gene SOS1 encodes a plasma membrane-bound Na+/H+ antiporter that exports Na+ to the extracellular space and imports H+ into the plant cell. Plants rely on these enzymes either to keep Na+ out of the cell or to sequester Na+ into vacuoles to avoid the toxic level of Na+ in the cytoplasm. Overexpression of AtNHX1 or SOS1 could improve salt tolerance in transgenic plants, but the improved salt tolerance is limited. NaCl at concentration >200 mM would kill AtNHX1-overexpressing or SOS1-overexpressing plants. Here it is shown that co-overexpressing AtNHX1 and SOS1 could further improve salt tolerance in transgenic Arabidopsis plants, making transgenic Arabidopsis able to tolerate up to 250 mM NaCl treatment. Furthermore, co-overexpression of AtNHX1 and SOS1 could significantly reduce yield loss caused by the combined stresses of heat and salt, confirming the hypothesis that stacked overexpression of two genes could substantially improve tolerance against multiple stresses. This research serves as a proof of concept for improving salt tolerance in other plants including crops. PMID:26985021

  13. Co-overexpressing a Plasma Membrane and a Vacuolar Membrane Sodium/Proton Antiporter Significantly Improves Salt Tolerance in Transgenic Arabidopsis Plants.

    PubMed

    Pehlivan, Necla; Sun, Li; Jarrett, Philip; Yang, Xiaojie; Mishra, Neelam; Chen, Lin; Kadioglu, Asim; Shen, Guoxin; Zhang, Hong

    2016-05-01

    The Arabidopsis gene AtNHX1 encodes a vacuolar membrane-bound sodium/proton (Na(+)/H(+)) antiporter that transports Na(+) into the vacuole and exports H(+) into the cytoplasm. The Arabidopsis gene SOS1 encodes a plasma membrane-bound Na(+)/H(+) antiporter that exports Na(+) to the extracellular space and imports H(+) into the plant cell. Plants rely on these enzymes either to keep Na(+) out of the cell or to sequester Na(+) into vacuoles to avoid the toxic level of Na(+) in the cytoplasm. Overexpression of AtNHX1 or SOS1 could improve salt tolerance in transgenic plants, but the improved salt tolerance is limited. NaCl at concentration >200 mM would kill AtNHX1-overexpressing or SOS1-overexpressing plants. Here it is shown that co-overexpressing AtNHX1 and SOS1 could further improve salt tolerance in transgenic Arabidopsis plants, making transgenic Arabidopsis able to tolerate up to 250 mM NaCl treatment. Furthermore, co-overexpression of AtNHX1 and SOS1 could significantly reduce yield loss caused by the combined stresses of heat and salt, confirming the hypothesis that stacked overexpression of two genes could substantially improve tolerance against multiple stresses. This research serves as a proof of concept for improving salt tolerance in other plants including crops. PMID:26985021

  14. Acquired tolerance and in situ detoxification of furfural and HMF through glucose metabolic pathways by Saccharomyces cerevisiae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lignocellulosic biomass conversion inhibitors furfural and HMF inhibit microbial growth and interfere with subsequent fermentation of ethanol. Numerous yeast genes were found to be associated with the inhibitor tolerance. However, little is known about system mechanisms of the tolerance and detoxi...

  15. Alternative oxidase pathway is involved in the exogenous SNP-elevated tolerance of Medicago truncatula to salt stress.

    PubMed

    Jian, Wei; Zhang, Da-Wei; Zhu, Feng; Wang, Shuo-Xun; Pu, Xiao-Jun; Deng, Xing-Guang; Luo, Shi-Shuai; Lin, Hong-Hui

    2016-04-01

    Exogenous application of sodium nitroprusside (SNP) would enhance the tolerance of plants to stress conditions. Some evidences suggested that nitric oxide (NO) could induce the expression of alternative oxidase (AOX). In this study, Medicago truncatula (Medicago) was chosen to study the role of AOX in the SNP-elevated resistance to salt stress. Our results showed that the expression of AOX genes (especially AOX1 and AOX2b1) and cyanide-resistant respiration rate (Valt) could be significantly induced by salt stress. Exogenous application of SNP could further enhance the expression of AOX genes and Valt. Exogenous application of SNP could alleviate the oxidative damage and photosynthetic damage caused by salt stress. However, the stress resistance was significantly decreased in the plants which were pretreated with n-propyl gallate (nPG). More importantly, the damage in nPG-pretreated plants could not be alleviated by application of SNP. Further study showed that effects of nPG on the activities of antioxidant enzymes were minor. These results showed that AOX pathway played an important role in the SNP-elevated resistance of Medicago to salt stress. AOX could contribute to regulating the accumulation of reactive oxygen (ROS) and protect of photosystem, and we proposed that all these were depend on the ability of maintaining the homeostasis of redox state. PMID:26962709

  16. A wheat PI4K gene whose product possesses threonine autophophorylation activity confers tolerance to drought and salt in Arabidopsis.

    PubMed

    Liu, Pei; Xu, Zhao-Shi; Pan-Pan, Lu; Hu, Di; Chen, Ming; Li, Lian-Cheng; Ma, You-Zhi

    2013-07-01

    Phosphoinositides are involved in regulation of recruitment and activity of signalling proteins in cell membranes. Phosphatidylinositol (PI) 4-kinases (PI4Ks) generate PI4-phosphate the precursor of regulatory phosphoinositides. No type II PI4K research on the abiotic stress response has previously been reported in plants. A stress-inducible type II PI4K gene, named TaPI4KIIγ, was obtained by de novo transcriptome sequencing of drought-treated wheat (Triticum aestivum). TaPI4KIIγ, localized on the plasma membrane, underwent threonine autophosphorylation, but had no detectable lipid kinase activity. Interaction of TaPI4KIIγ with wheat ubiquitin fusion degradation protein (TaUDF1) indicated that it might be hydrolysed by the proteinase system. Overexpression of TaPI4KIIγ revealed that it could enhance drought and salt stress tolerance during seed germination and seedling growth. A ubdkγ7 mutant, identified as an orthologue of TaPI4KIIγ in Arabidopsis, was sensitive to salt, polyethylene glycol (PEG), and abscisic acid (ABA), and overexpression of TaPI4KIIγ in the ubdkγ7 mutant compensated stress sensitivity. TaPI4KIIγ promoted root growth in Arabidopsis, suggesting that TaPI4KIIγ might enhance stress resistance by improving root growth. Overexpression of TaPI4KIIγ led to an altered expression level of stress-related genes and changes in several physiological traits that made the plants more tolerant to stress. The results provided evidence that overexpression of TaPI4KIIγ could improve drought and salt tolerance. PMID:23682116

  17. The Arabidopsis RNA-Binding Protein AtRGGA Regulates Tolerance to Salt and Drought Stress1[OPEN

    PubMed Central

    Ambrosone, Alfredo; Batelli, Giorgia; Nurcato, Roberta; Aurilia, Vincenzo; Punzo, Paola; Bangarusamy, Dhinoth Kumar; Ruberti, Ida; Sassi, Massimiliano; Leone, Antonietta; Costa, Antonello; Grillo, Stefania

    2015-01-01

    Salt and drought stress severely reduce plant growth and crop productivity worldwide. The identification of genes underlying stress response and tolerance is the subject of intense research in plant biology. Through microarray analyses, we previously identified in potato (Solanum tuberosum) StRGGA, coding for an Arginine Glycine Glycine (RGG) box-containing RNA-binding protein, whose expression was specifically induced in potato cell cultures gradually exposed to osmotic stress. Here, we show that the Arabidopsis (Arabidopsis thaliana) ortholog, AtRGGA, is a functional RNA-binding protein required for a proper response to osmotic stress. AtRGGA gene expression was up-regulated in seedlings after long-term exposure to abscisic acid (ABA) and polyethylene glycol, while treatments with NaCl resulted in AtRGGA down-regulation. AtRGGA promoter analysis showed activity in several tissues, including stomata, the organs controlling transpiration. Fusion of AtRGGA with yellow fluorescent protein indicated that AtRGGA is localized in the cytoplasm and the cytoplasmic perinuclear region. In addition, the rgga knockout mutant was hypersensitive to ABA in root growth and survival tests and to salt stress during germination and at the vegetative stage. AtRGGA-overexpressing plants showed higher tolerance to ABA and salt stress on plates and in soil, accumulating lower levels of proline when exposed to drought stress. Finally, a global analysis of gene expression revealed extensive alterations in the transcriptome under salt stress, including several genes such as ASCORBATE PEROXIDASE2, GLUTATHIONE S-TRANSFERASE TAU9, and several SMALL AUXIN UPREGULATED RNA-like genes showing opposite expression behavior in transgenic and knockout plants. Taken together, our results reveal an important role of AtRGGA in the mechanisms of plant response and adaptation to stress. PMID:25783413

  18. 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

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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

  4. Wheat CBL-interacting protein kinase 25 negatively regulates salt tolerance in transgenic wheat

    PubMed Central

    Jin, Xia; Sun, Tao; Wang, Xiatian; Su, Peipei; Ma, Jingfei; He, Guangyuan; Yang, Guangxiao

    2016-01-01

    CBL-interacting protein kinases are involved in plant responses to abiotic stresses, including salt stress. However, the negative regulating mechanism of this gene family in response to salinity is less reported. In this study, we evaluated the role of TaCIPK25 in regulating salt response in wheat. Under conditions of high salinity, TaCIPK25 expression was markedly down-regulated in roots. Overexpression of TaCIPK25 resulted in hypersensitivity to Na+ and superfluous accumulation of Na+ in transgenic wheat lines. TaCIPK25 expression did not decline in transgenic wheat and remained at an even higher level than that in wild-type wheat controls under high-salinity treatment. Furthermore, transmembrane Na+/H+ exchange was impaired in the root cells of transgenic wheat. These results suggested that TaCIPK25 negatively regulated salt response in wheat. Additionally, yeast-one-hybrid, β-glucuronidase activity and DNA-protein-interaction-enzyme-linked-immunosorbent assays showed that the transcription factor TaWRKY9 bound W-box in the TaCIPK25 promoter region. Quantitative real-time polymerase chain reaction assays showed concomitantly inverted expression patterns of TaCIPK25 and TaWRKY9 in wheat roots under salt treatment, ABA application and inhibition of endogenous ABA condition. Overall, based on our results, in a salt stress condition, the negative salt response in wheat involved TaCIPK25 with the expression regulated by TaWRKY9. PMID:27358166

  5. Wheat CBL-interacting protein kinase 25 negatively regulates salt tolerance in transgenic wheat.

    PubMed

    Jin, Xia; Sun, Tao; Wang, Xiatian; Su, Peipei; Ma, Jingfei; He, Guangyuan; Yang, Guangxiao

    2016-01-01

    CBL-interacting protein kinases are involved in plant responses to abiotic stresses, including salt stress. However, the negative regulating mechanism of this gene family in response to salinity is less reported. In this study, we evaluated the role of TaCIPK25 in regulating salt response in wheat. Under conditions of high salinity, TaCIPK25 expression was markedly down-regulated in roots. Overexpression of TaCIPK25 resulted in hypersensitivity to Na(+) and superfluous accumulation of Na(+) in transgenic wheat lines. TaCIPK25 expression did not decline in transgenic wheat and remained at an even higher level than that in wild-type wheat controls under high-salinity treatment. Furthermore, transmembrane Na(+)/H(+) exchange was impaired in the root cells of transgenic wheat. These results suggested that TaCIPK25 negatively regulated salt response in wheat. Additionally, yeast-one-hybrid, β-glucuronidase activity and DNA-protein-interaction-enzyme-linked-immunosorbent assays showed that the transcription factor TaWRKY9 bound W-box in the TaCIPK25 promoter region. Quantitative real-time polymerase chain reaction assays showed concomitantly inverted expression patterns of TaCIPK25 and TaWRKY9 in wheat roots under salt treatment, ABA application and inhibition of endogenous ABA condition. Overall, based on our results, in a salt stress condition, the negative salt response in wheat involved TaCIPK25 with the expression regulated by TaWRKY9. PMID:27358166

  6. Salt tolerance underlies the cryptic invasion of North American salt marshes by an introduced haplotype of the common reed Phragmites australis (Poaceae)

    USGS Publications Warehouse

    Vasquez, E.A.; Glenn, E.P.; Brown, J.J.; Guntenspergen, G.R.; Nelson, S.G.

    2005-01-01

    A distinct, non-native haplotype of the common reed Phragmites australis has become invasive in Atlantic coastal Spartina marshes. We compared the salt tolerance and other growth characteristics of the invasive M haplotype with 2 native haplotypes (F and AC) in greenhouse experiments. The M haplotype retained 50% of its growth potential up to 0.4 M NaCl, whereas the F and AC haplotypes did not grow above 0.1 M NaCl. The M haplotype produced more shoots per gram of rhizome tissue and had higher relative growth rates than the native haplotypes on both freshwater and saline water treatments. The M haplotype also differed from the native haplotypes in shoot water content and the biometrics of shoots and rhizomes. The results offer an explanation for how the M haplotype is able to spread in coastal salt marshes and support the conclusion of DNA analyses that the M haplotype is a distinct ecotype of P. australis. ?? Inter-Research 2005.

  7. Comparative mapping of HKT genes in wheat, barley, and rice, key determinants of Na+ transport, and salt tolerance.

    PubMed

    Huang, Shaobai; Spielmeyer, Wolfgang; Lagudah, Evans S; Munns, Rana

    2008-01-01

    Salt tolerance of plants depends on HKT transporters (High-affinity K(+) Transporter), which mediate Na(+)-specific transport or Na(+)-K(+) co-transport. Gene sequences closely related to rice HKT genes were isolated from hexaploid bread wheat (Triticum aestivum) or barley (Hordeum vulgare) for genomic DNA southern hybridization analysis. HKT gene sequences were mapped on chromosomal arms of wheat and barley using wheat chromosome substitution lines and barley-wheat chromosome addition lines. In addition, HKT gene members in the wild diploid wheat ancestors, T. monococcum (A(m) genome), T. urartu (A(u) genome), and Ae. tauschii (D(t) genome) were investigated. Variation in copy number for individual HKT gene members was observed between the barley, wheat, and rice genomes, and between the different wheat genomes. HKT2;1/2-like, HKT2;3/4-like, HKT1;1/2-like, HKT1;3-like, HKT1;4-like, and HKT1;5-like genes were mapped to the wheat-barley chromosome groups 7, 7, 2, 6, 2, and 4, respectively. Chromosomal regions containing HKT genes were syntenic between wheat and rice except for the chromosome regions containing the HKT1;5-like gene. Potential roles of HKT genes in Na(+) transport in rice, wheat, and barley are discussed. Determination of the chromosome locations of HKT genes provides a framework for future physiological and genetic studies investigating the relationships between HKT genes and salt tolerance in wheat and barley. PMID:18325922

  8. Over-expression of histone H3K4 demethylase gene JMJ15 enhances salt tolerance in Arabidopsis

    PubMed Central

    Shen, Yuan; Conde e Silva, Natalia; Audonnet, Laure; Servet, Caroline; Wei, Wei; Zhou, Dao-Xiu

    2014-01-01

    Histone H3 lysine 4 trimethylation (H3K4me3) has been shown to be involved in stress-responsive gene expression and gene priming in plants. However, the role of H3K4me3 resetting in the processes is not clear. In this work we studied the expression and function of Arabidopsis H3K4 demethylase gene JMJ15. We show that the expression of JMJ15 was relatively low and was limited to a number of tissues during vegetative growth but was higher in young floral organs. Over-expression of the gene in gain-of-function mutants reduced the plant height with accumulation of lignin in stems, while the loss-of-function mutation did not produce any visible phenotype. The gain-of-function mutants showed enhanced salt tolerance, whereas the loss-of-function mutant was more sensitive to salt compared to the wild type. Transcriptomic analysis revealed that over-expression of JMJ15 down-regulated many genes which are preferentially marked by H3K4me3 and H3K4me2. Many of the down-regulated genes encode transcription regulators involved in stress responses. The data suggest that increased JMJ15 levels may regulate the gene expression program that enhances stress tolerance. PMID:25009544

  9. 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

  10. 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

  11. Crystal structure of a major fragment of the salt-tolerant glutaminase from Micrococcus luteus K-3

    SciTech Connect

    Yoshimune, Kazuaki . E-mail: k.yoshimune@aist.go.jp; Shirakihara, Yasuo; Shiratori, Aya; Wakayama, Mamoru; Chantawannakul, Panuwan; Moriguchi, Mitsuaki

    2006-08-11

    Glutaminase of Micrococcus luteus K-3 (intact glutaminase; 48 kDa) is digested to a C-terminally truncated fragment (glutaminase fragment; 42 kDa) that shows higher salt tolerance than that of the intact glutaminase. The crystal structure of the glutaminase fragment was determined at 2.4 A resolution using multiple-wavelength anomalous dispersion (MAD). The glutaminase fragment is composed of N-terminal and C-terminal domains, and a putative catalytic serine-lysine dyad (S64 and K67) is located in a cleft of the N-terminal domain. Mutations of the S64 or K67 residues abolished the enzyme activity. The N-terminal domain has abundant glutamic acid residues on its surface, which may explain its salt-tolerant mechanism. A diffraction analysis of the intact glutaminase crystals (a twinning fraction of 0.43) located the glutaminase fragment in the unit cell but failed to turn up clear densities for the missing C-terminal portion of the molecule.

  12. Relationship between in vitro characterization and comparative efficacy of plant growth-promoting rhizobacteria for improving cucumber salt tolerance.

    PubMed

    Nadeem, Sajid Mahmood; Ahmad, Maqshoof; Naveed, Muhammad; Imran, Muhammad; Zahir, Zahir Ahmad; Crowley, David E

    2016-05-01

    Phosphate solubilization, 1-aminocyclopropane-1-carboxylic acid (ACC)-deaminase activity and production of siderophores and indole acetic acid (IAA) are well-known traits of plant growth-promoting rhizobacteria (PGPR). Here we investigated the expression of these traits as affected by salinity for three PGPR strains (Pseudomonas fluorescens, Bacillus megaterium and Variovorax paradoxus) at two salinity levels [2 and 5 % NaCl (w/v)]. Among the three strains, growth of B. megaterium was the least affected by high salinity. However, P. fluorescens was the best strain for maintaining ACC-deaminase activity, siderophore and IAA production under stressed conditions. V. paradoxus was the least tolerant to salts and had minimal growth and low PGPR trait expression under salt stress. Results of experiment examining the impact of bacterial inoculation on cucumber growth at three salinity levels [1 (normal), 7 and 10 dS m(-1)] revealed that P. fluorescens also had good rhizosphere competence and was the most effective for alleviating the negative impacts of salinity on cucumber growth. The results suggest that in addition to screening the PGPR regarding their effect on growth under salinity, PGPR trait expression is also an important aspect that may be useful for selecting the most promising PGPR bacterial strains for improving plant tolerance to salinity stress. PMID:26860842

  13. Genome-Wide Association Study Identifies Loci for Salt Tolerance during Germination in Autotetraploid Alfalfa (Medicago sativa L.) Using Genotyping-by-Sequencing

    PubMed Central

    Yu, Long-Xi; Liu, Xinchun; Boge, William; Liu, Xiang-Ping

    2016-01-01

    Salinity is one of major abiotic stresses limiting alfalfa (Medicago sativa L.) production in the arid and semi-arid regions in US and other counties. In this study, we used a diverse panel of alfalfa accessions previously described by Zhang et al. (2015) to identify molecular markers associated with salt tolerance during germination using genome-wide association study (GWAS) and genotyping-by-sequencing (GBS). Phenotyping was done by germinating alfalfa seeds under different levels of salt stress. Phenotypic data of adjusted germination rates and SNP markers generated by GBS were used for marker-trait association. Thirty six markers were significantly associated with salt tolerance in at least one level of salt treatments. Alignment of sequence tags to the Medicago truncatula genome revealed genetic locations of the markers on all chromosomes except chromosome 3. Most significant markers were found on chromosomes 1, 2, and 4. BLAST search using the flanking sequences of significant markers identified 14 putative candidate genes linked to 23 significant markers. Most of them were repeatedly identified in two or three salt treatments. Several loci identified in the present study had similar genetic locations to the reported QTL associated with salt tolerance in M. truncatula. A locus identified on chromosome 6 by this study overlapped with that by drought in our previous study. To our knowledge, this is the first report on mapping loci associated with salt tolerance during germination in autotetraploid alfalfa. Further investigation on these loci and their linked genes would provide insight into understanding molecular mechanisms by which salt and drought stresses affect alfalfa growth. Functional markers closely linked to the resistance loci would be useful for MAS to improve alfalfa cultivars with enhanced resistance to drought and salt stresses. PMID:27446182

  14. Genome-Wide Association Study Identifies Loci for Salt Tolerance during Germination in Autotetraploid Alfalfa (Medicago sativa L.) Using Genotyping-by-Sequencing.

    PubMed

    Yu, Long-Xi; Liu, Xinchun; Boge, William; Liu, Xiang-Ping

    2016-01-01

    Salinity is one of major abiotic stresses limiting alfalfa (Medicago sativa L.) production in the arid and semi-arid regions in US and other counties. In this study, we used a diverse panel of alfalfa accessions previously described by Zhang et al. (2015) to identify molecular markers associated with salt tolerance during germination using genome-wide association study (GWAS) and genotyping-by-sequencing (GBS). Phenotyping was done by germinating alfalfa seeds under different levels of salt stress. Phenotypic data of adjusted germination rates and SNP markers generated by GBS were used for marker-trait association. Thirty six markers were significantly associated with salt tolerance in at least one level of salt treatments. Alignment of sequence tags to the Medicago truncatula genome revealed genetic locations of the markers on all chromosomes except chromosome 3. Most significant markers were found on chromosomes 1, 2, and 4. BLAST search using the flanking sequences of significant markers identified 14 putative candidate genes linked to 23 significant markers. Most of them were repeatedly identified in two or three salt treatments. Several loci identified in the present study had similar genetic locations to the reported QTL associated with salt tolerance in M. truncatula. A locus identified on chromosome 6 by this study overlapped with that by drought in our previous study. To our knowledge, this is the first report on mapping loci associated with salt tolerance during germination in autotetraploid alfalfa. Further investigation on these loci and their linked genes would provide insight into understanding molecular mechanisms by which salt and drought stresses affect alfalfa growth. Functional markers closely linked to the resistance loci would be useful for MAS to improve alfalfa cultivars with enhanced resistance to drought and salt stresses. PMID:27446182

  15. SpAHA1 and SpSOS1 Coordinate in Transgenic Yeast to Improve Salt Tolerance.

    PubMed

    Zhou, Yang; Yin, Xiaochang; Duan, Ruijun; Hao, Gangping; Guo, Jianchun; Jiang, Xingyu

    2015-01-01

    In plant cells, the plasma membrane Na+/H+ antiporter SOS1 (salt overly sensitive 1) mediates Na+ extrusion using the proton gradient generated by plasma membrane H+-ATPases, and these two proteins are key plant halotolerance factors. In the present study, two genes from Sesuvium portulacastrum, encoding plasma membrane Na+/H+ antiporter (SpSOS1) and H+-ATPase (SpAHA1), were cloned. Localization of each protein was studied in tobacco cells, and their functions were analyzed in yeast cells. Both SpSOS1 and SpAHA1 are plasma membrane-bound proteins. Real-time polymerase chain reaction (PCR) analyses showed that SpSOS1 and SpAHA1 were induced by salinity, and their expression patterns in roots under salinity were similar. Compared with untransformed yeast cells, SpSOS1 increased the salt tolerance of transgenic yeast by decreasing the Na+ content. The Na+/H+ exchange activity at plasma membrane vesicles was higher in SpSOS1-transgenic yeast than in the untransformed strain. No change was observed in the salt tolerance of yeast cells expressing SpAHA1 alone; however, in yeast transformed with both SpSOS1 and SpAHA1, SpAHA1 generated an increased proton gradient that stimulated the Na+/H+ exchange activity of SpSOS1. In this scenario, more Na+ ions were transported out of cells, and the yeast cells co-expressing SpSOS1 and SpAHA1 grew better than the cells transformed with only SpSOS1 or SpAHA1. These findings demonstrate that the plasma membrane Na+/H+ antiporter SpSOS1 and H+-ATPase SpAHA1 can function in coordination. These results provide a reference for developing more salt-tolerant crops via co-transformation with the plasma membrane Na+/H+ antiporter and H+-ATPase. PMID:26340746

  16. SpAHA1 and SpSOS1 Coordinate in Transgenic Yeast to Improve Salt Tolerance

    PubMed Central

    Duan, Ruijun; Hao, Gangping; Guo, Jianchun; Jiang, Xingyu

    2015-01-01

    In plant cells, the plasma membrane Na+/H+ antiporter SOS1 (salt overly sensitive 1) mediates Na+ extrusion using the proton gradient generated by plasma membrane H+-ATPases, and these two proteins are key plant halotolerance factors. In the present study, two genes from Sesuvium portulacastrum, encoding plasma membrane Na+/H+ antiporter (SpSOS1) and H+-ATPase (SpAHA1), were cloned. Localization of each protein was studied in tobacco cells, and their functions were analyzed in yeast cells. Both SpSOS1 and SpAHA1 are plasma membrane-bound proteins. Real-time polymerase chain reaction (PCR) analyses showed that SpSOS1 and SpAHA1 were induced by salinity, and their expression patterns in roots under salinity were similar. Compared with untransformed yeast cells, SpSOS1 increased the salt tolerance of transgenic yeast by decreasing the Na+ content. The Na+/H+ exchange activity at plasma membrane vesicles was higher in SpSOS1-transgenic yeast than in the untransformed strain. No change was observed in the salt tolerance of yeast cells expressing SpAHA1 alone; however, in yeast transformed with both SpSOS1 and SpAHA1, SpAHA1 generated an increased proton gradient that stimulated the Na+/H+ exchange activity of SpSOS1. In this scenario, more Na+ ions were transported out of cells, and the yeast cells co-expressing SpSOS1 and SpAHA1 grew better than the cells transformed with only SpSOS1 or SpAHA1. These findings demonstrate that the plasma membrane Na+/H+ antiporter SpSOS1 and H+-ATPase SpAHA1 can function in coordination. These results provide a reference for developing more salt-tolerant crops via co-transformation with the plasma membrane Na+/H+ antiporter and H+-ATPase. PMID:26340746

  17. Overexpression of a Stress-Responsive NAC Transcription Factor Gene ONAC022 Improves Drought and Salt Tolerance in Rice.

    PubMed

    Hong, Yongbo; Zhang, Huijuan; Huang, Lei; Li, Dayong; Song, Fengming

    2016-01-01

    The NAC transcription factors play critical roles in regulating stress responses in plants. However, the functions for many of the NAC family members in rice are yet to be identified. In the present study, a novel stress-responsive rice NAC gene, ONAC022, was identified. Expression of ONAC022 was induced by drought, high salinity, and abscisic acid (ABA). The ONAC022 protein was found to bind specifically to a canonical NAC recognition cis-element sequence and showed transactivation activity at its C-terminus in yeast. The ONAC022 protein was localized to nucleus when transiently expressed in Nicotiana benthamiana. Three independent transgenic rice lines with overexpression of ONAC022 were generated and used to explore the function of ONAC022 in drought and salt stress tolerance. Under drought stress condition in greenhouse, soil-grown ONAC022-overexpressing (N22oe) transgenic rice plants showed an increased drought tolerance, leading to higher survival ratios and better growth than wild-type (WT) plants. When grown hydroponically in Hogland solution supplemented with 150 mM NaCl, the N22oe plants displayed an enhanced salt tolerance and accumulated less Na(+) in roots and shoots as compared to WT plants. Under drought stress condition, the N22oe plants exhibited decreased rates of water loss and transpiration, reduced percentage of open stomata and increased contents of proline and soluble sugars. However, the N22oe lines showed increased sensitivity to exogenous ABA at seed germination and seedling growth stages but contained higher level of endogenous ABA. Expression of some ABA biosynthetic genes (OsNCEDs and OsPSY), signaling and regulatory genes (OsPP2C02, OsPP2C49, OsPP2C68, OsbZIP23, OsAP37, OsDREB2a, and OsMYB2), and late stress-responsive genes (OsRAB21, OsLEA3, and OsP5CS1) was upregulated in N22oe plants. Our data demonstrate that ONAC022 functions as a stress-responsive NAC with transcriptional activator activity and plays a positive role in drought

  18. Productivity of sodic soils can be enhanced through the use of salt tolerant rice varieties and proper agronomic practices

    PubMed Central

    Singh, Y.P.; Mishra, V.K.; Singh, Sudhanshu; Sharma, D.K.; Singh, D.; Singh, U.S.; Singh, R.K.; Haefele, S.M.; Ismail, A.M.

    2016-01-01

    Regaining the agricultural potential of sodic soils in the Indo-Gangetic plains necessitates the development of suitable salt tolerant rice varieties to provide an entry for other affordable agronomic and soil manipulation measures. Thus selection of high yielding rice varieties across a range of sodic soils is central. Evaluation of breeding lines through on-station and on-farm farmers’ participatory varietal selection (FPVS) resulted in the identification of a short duration (110–115 days), high yielding and disease resistant salt-tolerant rice genotype ‘CSR-89IR-8’, which was later released as ‘CSR43’ in 2011. Several agronomic traits coupled with good grain quality and market value contributed to commercialization and quick adoption of this variety in the sodic areas of the Indo-Gangetic plains of eastern India. Management practices required for rice production in salt affected soils are evidently different from those in normal soils and practices for a short duration salt tolerant variety differ from those for medium to long duration varieties. Experiments were conducted at the Indian Council of Agricultural Research-Central Soil Salinity Research Institute (ICAR-CSSRI), Regional Research Station, Lucknow, Uttar Pradesh, India during 2011 and 2013 wet seasons, to test the hypothesis that combining matching management practices (Mmp) with an improved genotype would enhance productivity and profitability of rice in sodic soils. Mmp were developed on-station by optimizing existing best management practices (Bmp) recommended for the region to match the requirements of CSR43. The results revealed that transplanting 4 seedlings hill−1 at a spacing of 15 × 20 cm produced significantly higher yield over other treatments. The highest additional net gain was US$ 3.3 at 90 kg ha−1 N, and the lowest was US$ 0.4 at 150 kg ha−1 N. Above 150 kg ha−1, the additional net gain became negative, indicating decreasing returns from additional N

  19. Alleviation of salt stress in citrus seedlings inoculated with arbuscular mycorrhizal fungi depends on the rootstock salt tolerance.

    PubMed

    Navarro, Josefa M; Pérez-Tornero, Olaya; Morte, Asunción

    2014-01-01

    Seedlings of Cleopatra mandarin (Citrus reshni Hort. ex Tan.) and Alemow (Citrus macrophylla Wester) were inoculated with a mixture of AM fungi (Rhizophagus irregularis and Funneliformis mosseae) (+AM), or left non-inoculated (-AM). From forty-five days after fungal inoculation onwards, half of +AM or -AM plants were irrigated with nutrient solution containing 50 mM NaCl. Three months later, AM significantly increased plant growth in both Cleopatra mandarin and Alemow rootstocks. Plant growth was higher in salinized +AM plants than in non-salinized -AM plants, demonstrating that AM compensates the growth limitations imposed by salinity. Whereas AM-inoculated Cleopatra mandarin seedlings had a very good response under saline treatment, inoculation in Alemow did not alleviate the negative effect of salinity. The beneficial effect of mycorrhization is unrelated with protection against the uptake of Na or Cl and the effect of AM on these ions did not explain the different response of rootstocks. This response was related with the nutritional status since our findings confirm that AM fungi can alter host responses to salinity stress, improving more the P, K, Fe and Cu plant nutrition in Cleopatra mandarin than in Alemow plants. AM inoculation under saline treatments also increased root Mg concentration but it was higher in Cleopatra mandarin than in Alemow. This could explain why AM fungus did not completely recovered chlorophyll concentrations in Alemow and consequently it had lower photosynthesis rate than control plants. AM fungi play an essential role in citrus rootstock growth and biomass production although the intensity of this response depends on the rootstock salinity tolerance. PMID:23859560

  20. Cloning and characterization of a maize SnRK2 protein kinase gene confers enhanced salt tolerance in transgenic Arabidopsis.

    PubMed

    Ying, Sheng; Zhang, Deng-Feng; Li, Hui-Yong; Liu, Ying-Hui; Shi, Yun-Su; Song, Yan-Chun; Wang, Tian-Yu; Li, Yu

    2011-09-01

    SnRK2 (sucrose non-fermenting 1-related protein kinases 2) represents a unique family of protein kinase in regulating signaling transduction in plants. Although the regulatory mechanisms of SnRK2 have been well demonstrated in Arabidopsis thaliana, their functions in maize are still unknown. In our study, we cloned an SnRK2 gene from maize, ZmSAPK8, which encoded a putative homolog of the rice SAPK8 protein. ZmSAPK8 had two copies in the maize genome and harbored eight introns in its coding region. We demonstrated that ZmSAPK8 expressed differentially in various organs of maize plants and was up-regulated by high-salinity and drought treatment. A green fluorescent protein (GFP)-tagged ZmSAPK8 showed subcellular localization in the cell membrane, cytoplasm and nucleus. In vitro kinase assays indicated that ZmSAPK8 preferred Mn(2+) to Mg(2+) as cofactor for phosphorylation, and Ser-182 and Thr-183 in activation loop was important for its activity. Heterologous overexpression of ZmSAPK8 in Arabidopsis could significantly strengthen tolerance to salt stress. Under salt treatment, ZmSAPK8-overexpressed transgenic plants exhibited higher germination rate and proline content, low electrolyte leakage and higher survival rate than wild type. Further analysis indicated that transgenic plants showed increased transcription of the stress-related genes, RD29A, RD29B, RAB18, ABI1, DREB2A and P5CS1, under high-salinity conditions. The results demonstrated that ZmSAPK8 was involved in diverse stress signal transduction. Moreover, no obvious adverse effects on growth and development in the ZmSAPK8-overexpressed transgenic plants implied that ZmSAPK8 was potentially useful in transgenic breeding to improve salt tolerance in crops. PMID:21638061

  1. 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

  2. A putative soybean GmsSOS1 confers enhanced salt tolerance to transgenic Arabidopsis sos1-1 mutant.

    PubMed

    Nie, Wang-Xing; Xu, Lin; Yu, Bing-Jun

    2015-01-01

    The cDNA of GmsSOS1, a putative plasma membrane Na(+)/H(+) antiporter gene isolated from Glycine max, Glycine soja, and their hybrid, was constructed into plant expression vector pCAMBIA 1300 and then transformed with Agrobacterium tumefaciens under the control of CaMV 35S promoter to Arabidopsis thaliana wild-type (WT) and mutant (atsos1-1) plants. By hygromycin resistance detection and PCR analysis, transgenic plants (WT35S:GmsSOS1 and atsos1-1 35S:GmsSOS1) were obtained. Seed germination, seedling growth, and Na(+) contents in roots and shoots were analytically compared among WT, atsos1-1 mutant, and their transgenic lines under salt stress. The results showed that when GmsSOS1 was integrated into the genome of A. thaliana, the inhibitions of salt stress on seed germination and seedling growth were all significantly improved, and enhanced salt tolerance was displayed, which may be attributed to the decrease of Na(+) absorption in roots and transportation in shoots of the transgenic lines, especially for that of atsos1-1 mutant. PMID:24934653

  3. Genetic transformation and expression of transgenic lines of Populus x euramericana with insect-resistance and salt-tolerance genes.

    PubMed

    Yang, R L; Wang, A X; Zhang, J; Dong, Y; Yang, M S; Wang, J M

    2016-01-01

    We characterized new transgenic varieties of poplar with multiple insect-resistant and salt stress tolerant genes. Two insect-resistant Bacillus thuringiensis (Bt) genes, Cry1Ac and Cry3A, and a salt-tolerant gene, Betaine aldehyde dehydrogenase (BADH) were inserted into a vector, p209-Cry1Ac-Cry3A-BADH. The clone of Populus x euramericana was transformed by the vector using the Agrobacterium-mediated method. Three transgenic lines were assessed using genetic detection and resistance expression analysis. PCR revealed that exogenous genes Cry1Ac, Cry3A, BADH and selective marker gene NPTII were present in three transgenic lines. Quantitative real-time PCR (qPCR) showed significant differences in the transcriptional abundance of three exogenous genes in different lines. Results of assays for Bt toxic proteins showed that the Cry1Ac and Cry3A toxic protein content of each line was 12.83-26.32 and 2108.91-2724.79 ng/g, respectively. The Cry1Ac toxic protein content of different lines was significantly different; the Cry3A toxic protein content was about 100 times higher than that of the Cry1Ac toxic protein. The insect-resistance test revealed the mortality rate of transgenic lines to Hyphantria cunea L1 larvae varied by 42.2-66.7%, which was significantly higher than non-transgenic lines. The mortality rate of L1 and L2 Plagiodera versicolora larvae was 100%. The insecticidal effect of transgenic lines to P. versicolora larvae was higher than that to H. cunea larvae. NaCl stress tolerance of three transgenic lines under 3-6% NaCl concentration was significantly higher than that of non-transgenic lines. PMID:27173305

  4. Synechococcus sp. PCC7942 Transformed with Escherichia coli bet Genes Produces Glycine Betaine from Choline and Acquires Resistance to Salt Stress.

    PubMed Central

    Nomura, M.; Ishitani, M.; Takabe, T.; Rai, A. K.; Takabe, T.

    1995-01-01

    Synechococcus sp. PCC7942, a fresh water cyanobacterium, was transformed by a shuttle plasmid that contains a 9-kb fragment encoding the Escherichia coli bet gene cluster, i.e. betA (choline dehydrogenase), betB (betaine aldehyde dehydrogenase), betI (a putative regulatory protein), and betT (the choline transport system). The expression of these genes was demonstrated in the cyanobacterial cells (bet-containing cells) by northern blot analysis, as well as by the detection of glycine betaine by 1H nuclear magnetic resonance in cells supplemented with choline. Endogenous choline was not detected in either control or bet-containing cells. Both control and bet-containing cyanobacterial cells were found to import choline in an energy-dependent process, although this import was restricted only to bet-containing cells in conditions of salt stress. Glycine betaine was found to accumulate to a concentration of 45 mM in bet-containing cyanobacterial cells, and this resulted in a stabilization of the photosynthetic activities of photosystems I and II, higher phycobilisome contents, and general protective effects against salt stress when compared to control cells. The growth of bet-containing cells was much faster in the presence of 0.375 M NaCl than that of control cells, indicating that the transformant acquired resistance to salt stress. PMID:12228394

  5. 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

  6. 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

  7. Variations in DREB1A and VP1.1 Genes Show Association with Salt Tolerance Traits in Wild Tomato (Solanum pimpinellifolium)

    PubMed Central

    Rao, Eguru Sreenivasa; Kadirvel, Palchamy; Symonds, Rachael C.; Geethanjali, Subramaniam; Thontadarya, Ramadihalli N.; Ebert, Andreas W.

    2015-01-01

    Association analysis was conducted in a core collection of 94 genotypes of Solanum pimpinellifolium to identify variations linked to salt tolerance traits (physiological and yield traits under salt stress) in four candidate genes viz., DREB1A, VP1.1, NHX1, and TIP. The candidate gene analysis covered a concatenated length of 4594 bp per individual and identified five SNP/Indels in DREB1A and VP1.1 genes explaining 17.0% to 25.8% phenotypic variation for various salt tolerance traits. Out of these five alleles, one at 297 bp in DREB1A had in-frame deletion of 6 bp (CTGCAT) or 12 bp (CTGCATCTGCAT), resulting in two alleles, viz., SpDREB1A_297_6 and SpDREB1A_297_12. These alleles individually or as haplotypes accounted for maximum phenotypic variance of about 25% for various salt tolerance traits. Design of markers for selection of the favorable alleles/haplotypes will hasten marker-assisted introgression of salt tolerance from S. pimpinellifolium into cultivated tomato. PMID:26161546

  8. Variations in DREB1A and VP1.1 Genes Show Association with Salt Tolerance Traits in Wild Tomato (Solanum pimpinellifolium).

    PubMed

    Rao, Eguru Sreenivasa; Kadirvel, Palchamy; Symonds, Rachael C; Geethanjali, Subramaniam; Thontadarya, Ramadihalli N; Ebert, Andreas W

    2015-01-01

    Association analysis was conducted in a core collection of 94 genotypes of Solanum pimpinellifolium to identify variations linked to salt tolerance traits (physiological and yield traits under salt stress) in four candidate genes viz., DREB1A, VP1.1, NHX1, and TIP. The candidate gene analysis covered a concatenated length of 4594 bp per individual and identified five SNP/Indels in DREB1A and VP1.1 genes explaining 17.0% to 25.8% phenotypic variation for various salt tolerance traits. Out of these five alleles, one at 297 bp in DREB1A had in-frame deletion of 6 bp (CTGCAT) or 12 bp (CTGCATCTGCAT), resulting in two alleles, viz., SpDREB1A_297_6 and SpDREB1A_297_12. These alleles individually or as haplotypes accounted for maximum phenotypic variance of about 25% for various salt tolerance traits. Design of markers for selection of the favorable alleles/haplotypes will hasten marker-assisted introgression of salt tolerance from S. pimpinellifolium into cultivated tomato. PMID:26161546

  9. Mechanisms of salt tolerance in habanero pepper plants (Capsicum chinense Jacq.): Proline accumulation, ions dynamics and sodium root-shoot partition and compartmentation

    PubMed Central

    Bojórquez-Quintal, Emanuel; Velarde-Buendía, Ana; Ku-González, Ángela; Carillo-Pech, Mildred; Ortega-Camacho, Daniela; Echevarría-Machado, Ileana; Pottosin, Igor; Martínez-Estévez, Manuel

    2014-01-01

    Despite its economic relevance, little is known about salt tolerance mechanisms in pepper plants. To address this question, we compared differences in responses to NaCl in two Capsicum chinense varieties: Rex (tolerant) and Chichen-Itza (sensitive). Under salt stress (150 mM NaCl over 7 days) roots of Rex variety accumulated 50 times more compatible solutes such as proline compared to Chichen-Itza. Mineral analysis indicated that Na+ is restricted to roots by preventing its transport to leaves. Fluorescence analysis suggested an efficient Na+ compartmentalization in vacuole-like structures and in small intracellular compartments in roots of Rex variety. At the same time, Na+ in Chichen-Itza plants was compartmentalized in the apoplast, suggesting substantial Na+ extrusion. Rex variety was found to retain more K+ in its roots under salt stress according to a mineral analysis and microelectrode ion flux estimation (MIFE). Vanadate-sensitive H+ efflux was higher in Chichen-Itza variety plants, suggesting a higher activity of the plasma membrane H+-ATPase, which fuels the extrusion of Na+, and, possibly, also the re-uptake of K+. Our results suggest a combination of stress tolerance mechanisms, in order to alleviate the salt-induced injury. Furthermore, Na+ extrusion to apoplast does not appear to be an efficient strategy for salt tolerance in pepper plants. PMID:25429292

  10. 40 CFR 180.383 - Sodium salt of acifluorfen; tolerances for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... established for combined residues of the herbicide sodium salt of acifluorfen, sodium 5- -2-nitrobenzoate, and its metabolites (the corresponding acid, methyl ester, and amino analogues) in or on the following raw agricultural commodities: Commodity Parts per million Peanut 0.1 Rice, grain 0.1 Rice, straw 0.2 Soybean,...

  11. Development and characterization of seashore paspulum SSR markers and identification of markers associated with salt tolerance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil salinity is a major environmental factor limiting plant growth and productivity. Restrictions on water-use due to water shortages have resulted in the use of secondary water sources, which are often higher in salt, to irrigate turf. Furthermore, the increasing use of irrigation, which is highly...

  12. 40 CFR 180.383 - Sodium salt of acifluorfen; tolerances for residues.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... established for combined residues of the herbicide sodium salt of acifluorfen, sodium 5- -2-nitrobenzoate, and its metabolites (the corresponding acid, methyl ester, and amino analogues) in or on the following raw agricultural commodities: Commodity Parts per million Peanut 0.1 Rice, grain 0.1 Rice, straw 0.2 Soybean,...

  13. Tolerance of roadside and old field populations of common teasel (Dipsacus fullonum subsp. sylvestris) to salt and low osmotic potentials during germination

    PubMed Central

    Beaton, Laura L.; Dudley, Susan A.

    2013-01-01

    Plants inhabiting degraded habitats must contend with stressful environments. However, their ability to adapt may be constrained by available genetic variation and genetic correlations between traits. Here, we examine the correlation between salt and drought tolerance in germinating seeds from contrasting populations of common teasel (Dipsacus fullonum subsp. sylvestris) growing on roadsides that experience high salinity due to de-icing salts, or growing in an old field site, remote from roadsides and free of salinity stress. We examined the contribution of drought and salinity tolerance to the tolerance of roadside conditions in seedlings from five maternal families from three roadside and three old field populations. Germination and early growth were compared under high salinity, low water potential set at −0.5 MPa with solutions of polyethylene glycol 8000, sodium chloride or vermiculite wetted to −0.5 MPa with distilled water. Root length and the emergence of cotyledons (where appropriate) were used as a measure of performance. Maternal families from roadside populations displayed greater tolerance of both high salinity and drought than families from old field populations. However, no maternal family possessed tolerance to both drought and salinity. Salt and drought tolerance during germination were not correlated, indicating that they are separate traits in this species.

  14. Mapping QTLs for Salt Tolerance in Rice (Oryza sativa L.) by Bulked Segregant Analysis of Recombinant Inbred Lines Using 50K SNP Chip

    PubMed Central

    Kumar, Vinod; Singh, Balwant; Rao, AR; Mithra SV, Amitha; Singh, Ashok K.; Singh, Nagendra K.

    2016-01-01

    Soil salinity is a major constraint to rice production in large inland and coastal areas around the world. Modern high yielding rice varieties are particularly sensitive to high salt stress. There are salt tolerant landraces and traditional varieties of rice but with limited information on genomic regions (QTLs) and genes responsible for their tolerance. Here we describe a method for rapid identification of QTLs for reproductive stage salt tolerance in rice using bulked segregant analysis (BSA) of bi-parental recombinant inbred lines (RIL). The number of RILs required for the creation of two bulks with extreme phenotypes was optimized to be thirty each. The parents and bulks were genotyped using a 50K SNP chip to identify genomic regions showing homogeneity for contrasting alleles of polymorphic SNPs in the two bulks. The method was applied to ‘CSR11/MI48’ RILs segregating for reproductive stage salt tolerance. Genotyping of the parents and RIL bulks, made on the basis of salt sensitivity index for grain yield, revealed 6,068 polymorphic SNPs and 21 QTL regions showing homogeneity of contrasting alleles in the two bulks. The method was validated further with ‘CSR27/MI48’ RILs used earlier for mapping salt tolerance QTLs using low-density SSR markers. BSA with 50K SNP chip revealed 5,021 polymorphic loci and 34 QTL regions. This not only confirmed the location of previously mapped QTLs but also identified several new QTLs, and provided a rapid way to scan the whole genome for mapping QTLs for complex agronomic traits in rice. PMID:27077373

  15. Mapping QTLs for Salt Tolerance in Rice (Oryza sativa L.) by Bulked Segregant Analysis of Recombinant Inbred Lines Using 50K SNP Chip.

    PubMed

    Tiwari, Sushma; Sl, Krishnamurthy; Kumar, Vinod; Singh, Balwant; Rao, A R; Mithra Sv, Amitha; Rai, Vandna; Singh, Ashok K; Singh, Nagendra K

    2016-01-01

    Soil salinity is a major constraint to rice production in large inland and coastal areas around the world. Modern high yielding rice varieties are particularly sensitive to high salt stress. There are salt tolerant landraces and traditional varieties of rice but with limited information on genomic regions (QTLs) and genes responsible for their tolerance. Here we describe a method for rapid identification of QTLs for reproductive stage salt tolerance in rice using bulked segregant analysis (BSA) of bi-parental recombinant inbred lines (RIL). The number of RILs required for the creation of two bulks with extreme phenotypes was optimized to be thirty each. The parents and bulks were genotyped using a 50K SNP chip to identify genomic regions showing homogeneity for contrasting alleles of polymorphic SNPs in the two bulks. The method was applied to 'CSR11/MI48' RILs segregating for reproductive stage salt tolerance. Genotyping of the parents and RIL bulks, made on the basis of salt sensitivity index for grain yield, revealed 6,068 polymorphic SNPs and 21 QTL regions showing homogeneity of contrasting alleles in the two bulks. The method was validated further with 'CSR27/MI48' RILs used earlier for mapping salt tolerance QTLs using low-density SSR markers. BSA with 50K SNP chip revealed 5,021 polymorphic loci and 34 QTL regions. This not only confirmed the location of previously mapped QTLs but also identified several new QTLs, and provided a rapid way to scan the whole genome for mapping QTLs for complex agronomic traits in rice. PMID:27077373

  16. Regulation of cation transport in Saccharomyces cerevisiae by the salt tolerance gene HAL3.

    PubMed Central

    Ferrando, A; Kron, S J; Rios, G; Fink, G R; Serrano, R

    1995-01-01

    Dynamic regulation of ion transport is essential for homeostasis as cells confront changes in their environment. The gene HAL3 encodes a novel component of this regulatory circuit in the yeast Saccharomyces cerevisiae. Overexpression of HAL3 improves growth of wild-type cells exposed to toxic concentrations of sodium and lithium and suppresses the salt sensitivity conferred by mutation of the calcium-dependent protein phosphatase calcineurin. Null mutants of HAL3 display salt sensitivity. The sequence of HAL3 gives little clue to its function. However, alterations in intracellular cation concentrations associated with changes in HAL3 expression suggest that HAL3 activity may directly increase cytoplasmic K+ and decrease Na+ and Li+. Cation efflux in S. cerevisiae is mediated by the P-type ATPase encoded by the ENA1/PMR24 gene, a putative plasma membrane Na+ pump whose expression is salt induced. Acting in concert with calcineurin, HAL3 is necessary for full activation of ENA1 expression. This functional complementarity is also reflected in the participation of both proteins in recovery from alpha-factor-induced growth arrest. Recently, HAL3 was isolated as a gene (named SIS2) which when overexpressed partially relieves loss of transcription of G1 cyclins in mutants lacking the protein phosphatase Sit4p. Therefore, HAL3 influences cell cycle control and ion homeostasis, acting in parallel to the protein phosphatases Sit4p and calcineurin. PMID:7565698

  17. Hydrogen sulfide enhances salt tolerance through nitric oxide-mediated maintenance of ion homeostasis in barley seedling roots

    PubMed Central

    Chen, Juan; Wang, Wen-Hua; Wu, Fei-Hua; He, En-Ming; Liu, Xiang; Shangguan, Zhou-Ping; Zheng, Hai-Lei

    2015-01-01

    Hydrogen sulfide (H2S) and nitric oxide (NO) are emerging as messenger molecules involved in the modulation of plant physiological processes. Here, we investigated a signalling network involving H2S and NO in salt tolerance pathway of barley. NaHS, a donor of H2S, at a low concentration of either 50 or 100 μM, had significant rescue effects on the 150 mM NaCl-induced inhibition of plant growth and modulated the K+/Na+ balance by decreasing the net K+ efflux and increasing the gene expression of an inward-rectifying potassium channel (HvAKT1) and a high-affinity K+ uptake system (HvHAK4). H2S and NO maintained the lower Na+ content in the cytoplast by increasing the amount of PM H+-ATPase, the transcriptional levels of PM H+-ATPase (HvHA1) and Na+/H+ antiporter (HvSOS1). H2S and NO modulated Na+ compartmentation into the vacuoles with up-regulation of the transcriptional levels of vacuolar Na+/H+ antiporter (HvVNHX2) and H+-ATPase subunit β (HvVHA-β) and increased in the protein expression of vacuolar Na+/H+ antiporter (NHE1). H2S mimicked the effect of sodium nitroprusside (SNP) by increasing NO production, whereas the function was quenched with the addition of NO scavenger. These results indicated that H2S increased salt tolerance by maintaining ion homeostasis, which were mediated by the NO signal. PMID:26213372

  18. 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

  19. The Redox-Sensitive Chloroplast Trehalose-6-Phosphate Phosphatase AtTPPD Regulates Salt Stress Tolerance

    PubMed Central

    Krasensky, Julia; Broyart, Caroline; Rabanal, Fernando A.

    2014-01-01

    Abstract Aims: High salinity stress impairs plant growth and development. Trehalose metabolism has been implicated in sugar signaling, and enhanced trehalose metabolism can positively regulate abiotic stress tolerance. However, the molecular mechanism(s) of the stress-related trehalose pathway and the role of individual trehalose biosynthetic enzymes for stress tolerance remain unclear. Results: Trehalose-6-phosphate phosphatase (TPP) catalyzes the final step of trehalose metabolism. Investigating the subcellular localization of the Arabidopsis thaliana TPP family members, we identified AtTPPD as a chloroplast-localized enzyme. Plants deficient in AtTPPD were hypersensitive, whereas plants overexpressing AtTPPD were more tolerant to high salinity stress. Elevated stress tolerance of AtTPPD overexpressors correlated with high starch levels and increased accumulation of soluble sugars, suggesting a role for AtTPPD in regulating sugar metabolism under salinity conditions. Biochemical analyses indicate that AtTPPD is a target of post-translational redox regulation and can be reversibly inactivated by oxidizing conditions. Two cysteine residues were identified as the redox-sensitive sites. Structural and mutation analyses suggest that the formation of an intramolecular disulfide bridge regulates AtTPPD activity. Innovation: The activity of different AtTPP isoforms, located in the cytosol, nucleus, and chloroplasts, can be redox regulated, suggesting that the trehalose metabolism might relay the redox status of different cellular compartments to regulate diverse biological processes such as stress responses. Conclusion: The evolutionary conservation of the two redox regulatory cysteine residues of TPPs in spermatophytes indicates that redox regulation of TPPs might be a common mechanism enabling plants to rapidly adjust trehalose metabolism to the prevailing environmental and developmental conditions. Antioxid. Redox Signal. 21, 1289–1304. PMID:24800789

  20. Rice OVERLY TOLERANT TO SALT 1 (OTS1) SUMO protease is a positive regulator of seed germination and root development.

    PubMed

    Srivastava, Anjil Kumar; Zhang, Cunjin; Sadanandom, Ari

    2016-05-01

    Salinity is one of the major environmental stresses affecting rice production worldwide. Improving rice salt tolerance is a critical step for sustainable food production. Posttranslational modifications of proteins greatly expand proteome diversity, increase functionality and allow quick responses to environmental stresses, all at low cost to the cell. SUMO mediated modification of substrate proteins is a highly dynamic process governed by the balance of activities of SUMO E3 ligases and deconjugating SUMO proteases. In recent years, SUMO (Small Ubiquitin like Modifier) conjugation of proteins has emerged as an influential regulator of stress signaling in the model plant Arabidopsis. However SUMOylation remain largely under studied in crop plants. We recently identified the SUMO protease gene family in rice and demonstrated a role for OsOTS1 SUMO proteases in salt stress. Interestingly, rice plants silencing OsOTS1 also show significantly reduced germination rate. Knockdown of OsOTS1 gene expression affects root growth by primarily reducing cell size rather than cell division. PMID:27119209

  1. Draft Genome Sequence of Frankia sp. Strain CcI6, a Salt-Tolerant Nitrogen-Fixing Actinobacterium Isolated from the Root Nodule of Casuarina cunninghamiana

    PubMed Central

    Mansour, Samira R.; Oshone, Rediet; Hurst, Sheldon G.; Morris, Krystalynne; Thomas, W. Kelley

    2014-01-01

    Members of the actinomycete genus Frankia form a nitrogen-fixing symbiosis with 8 different families of actinorhizal plants. We report a 5.57-Mbp draft genome sequence for Frankia sp. strain CcI6, a salt-tolerant nitrogen-fixing actinobacterium isolated from root nodules of Casurina cunninghamiana grown in Egyptian soils. PMID:24435877

  2. Functional Environmental Screening of a Metagenomic Library Identifies stlA; A Unique Salt Tolerance Locus from the Human Gut Microbiome

    PubMed Central

    Culligan, Eamonn P.; Sleator, Roy D.; Marchesi, Julian R.; Hill, Colin

    2013-01-01

    Functional environmental screening of metagenomic libraries is a powerful means to identify and assign function to novel genes and their encoded proteins without any prior sequence knowledge. In the current study we describe the identification and subsequent analysis of a salt-tolerant clone from a human gut metagenomic library. Following transposon mutagenesis we identified an unknown gene (stlA, for “salt tolerance locus A”) with no current known homologues in the databases. Subsequent cloning and expression in Escherichia coli MKH13 revealed that stlA confers a salt tolerance phenotype in its surrogate host. Furthermore, a detailed in silico analysis was also conducted to gain additional information on the properties of the encoded StlA protein. The stlA gene is rare when searched against human metagenome datasets such as MetaHit and the Human Microbiome Project and represents a novel and unique salt tolerance determinant which appears to be found exclusively in the human gut environment. PMID:24349412

  3. Draft Genome Sequence of Frankia sp. Strain CcI6, a Salt-Tolerant Nitrogen-Fixing Actinobacterium Isolated from the Root Nodule of Casuarina cunninghamiana.

    PubMed

    Mansour, Samira R; Oshone, Rediet; Hurst, Sheldon G; Morris, Krystalynne; Thomas, W Kelley; Tisa, Louis S

    2014-01-01

    Members of the actinomycete genus Frankia form a nitrogen-fixing symbiosis with 8 different families of actinorhizal plants. We report a 5.57-Mbp draft genome sequence for Frankia sp. strain CcI6, a salt-tolerant nitrogen-fixing actinobacterium isolated from root nodules of Casurina cunninghamiana grown in Egyptian soils. PMID:24435877

  4. The Cotton WRKY Gene GhWRKY41 Positively Regulates Salt and Drought Stress Tolerance in Transgenic Nicotiana benthamiana

    PubMed Central

    Chen, Xiaobo; Lu, Wenjing; Li, Han; Wang, Xiuling; Hao, Lili; Guo, Xingqi

    2015-01-01

    WRKY transcription factors constitute a very large family of proteins in plants and participate in modulating plant biological processes, such as growth, development and stress responses. However, the exact roles of WRKY proteins are unclear, particularly in non-model plants. In this study, Gossypium hirsutum WRKY41 (GhWRKY41) was isolated and transformed into Nicotiana benthamiana. Our results showed that overexpression of GhWRKY41 enhanced the drought and salt stress tolerance of transgenic Nicotiana benthamiana. The transgenic plants exhibited lower malondialdehyde content and higher antioxidant enzyme activity, and the expression of antioxidant genes was upregulated in transgenic plants exposed to osmotic stress. A β-glucuronidase (GUS) staining assay showed that GhWRKY41 was highly expressed in the stomata when plants were exposed to osmotic stress, and plants overexpressing GhWRKY41 exhibited enhanced stomatal closure when they were exposed to osmotic stress. Taken together, our findings demonstrate that GhWRKY41 may enhance plant tolerance to stress by functioning as a positive regulator of stoma closure and by regulating reactive oxygen species (ROS) scavenging and the expression of antioxidant genes. PMID:26562293

  5. Over-expression of ascorbate peroxidase in tobacco chloroplasts enhances the tolerance to salt stress and water deficit.

    PubMed

    Badawi, Ghazi Hamid; Kawano, Naoyoshi; Yamauchi, Yasuo; Shimada, Emi; Sasaki, Ryozo; Kubo, Akihiro; Tanaka, Kiyoshi

    2004-06-01

    The role of APX (ascorbate peroxidase) in protection against oxidative stress was examined using transgenic tobacco plants. The full length cDNA, coding Arabidopsis thaliana L. APX fused downstream to the chloroplast transit sequence from A. thaliana glutathione reductase, was cloned into appropriate binary vector and mobilized into Agrobacterium tumefaciens C58C2. Leaf discs were infected with the Agrobacterium and cultured on medium supplied with kanamycin. The incorporation of the gene in tobacco genome was confirmed by Southern dot blot hybridization. Transgenic lines were generated, and the line Chl-APX5 shown to have 3.8-fold the level of APX activity in the wild-type plants. The isolated chloroplasts from this line showed higher APX activity. During early investigation, this line showed enhanced tolerance to the active oxygen-generating paraquat and sodium sulphite. The first generation of this line, also, showed enhanced tolerance to salt, PEG and water stresses, as determined by net photosynthesis. The present data indicate that overproducing the cytosolic APX in tobacco chloroplasts reduces the toxicity of H(2)O(2). PMID:15153190

  6. MzPIP2;1: An Aquaporin Involved in Radial Water Movement in Both Water Uptake and Transportation, Altered the Drought and Salt Tolerance of Transgenic Arabidopsis

    PubMed Central

    Lei, Qiong; Feng, Chao; Gao, Yinan; Zheng, Xiaodong; Zhao, Yu; Wang, Zhi; Kong, Jin

    2015-01-01

    Background Plants are unavoidably subjected to various abiotic stressors, including high salinity, drought and low temperature, which results in water deficit and even death. Water uptake and transportation play a critical role in response to these stresses. Many aquaporin proteins, localized at different tissues, function in various transmembrane water movements. We targeted at the key aquaporin in charge of both water uptake in roots and radial water transportation from vascular tissues through the whole plant. Results The MzPIP2;1 gene encoding a plasma membrane intrinsic protein was cloned from salt-tolerant apple rootstock Malus zumi Mats. The GUS gene was driven by MzPIP2;1 promoter in transgenic Arabidopsis. It indicated that MzPIP2;1 might function in the epidermal and vascular cells of roots, parenchyma cells around vessels through the stems and vascular tissues of leaves. The ectopically expressed MzPIP2;1 conferred the transgenic Arabidopsis plants enhanced tolerance to slight salt and drought stresses, but sensitive to moderate salt stress, which was indicated by root length, lateral root number, fresh weight and K+/Na+ ratio. In addition, the possible key cis-elements in response to salt, drought and cold stresses were isolated by the promoter deletion experiment. Conclusion The MzPIP2;1 protein, as a PIP2 aquaporins subgroup member, involved in radial water movement, controls water absorption and usage efficiency and alters transgenic plants drought and salt tolerance. PMID:26562158

  7. 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

  8. Brassica RNA binding protein ERD4 is involved in conferring salt, drought tolerance and enhancing plant growth in Arabidopsis.

    PubMed

    Rai, Archana N; Tamirisa, Srinath; Rao, K V; Kumar, Vinay; Suprasanna, P

    2016-03-01

    'Early responsive to dehydration' (ERD) genes are a group of plant genes having functional roles in plant stress tolerance and development. In this study, we have isolated and characterized a Brassica juncea 'ERD' gene (BjERD4) which encodes a novel RNA binding protein. The expression pattern of ERD4 analyzed under different stress conditions showed that transcript levels were increased with dehydration, sodium chloride, low temperature, heat, abscisic acid and salicylic acid treatments. The BjERD4 was found to be localized in the chloroplasts as revealed by Confocal microscopy studies. To study the function, transgenic Arabidopsis plants were generated and analyzed for various morphological and physiological parameters. The overexpressing transgenic lines showed significant increase in number of leaves with more leaf area and larger siliques as compared to wild type plants, whereas RNAi:ERD4 transgenic lines showed reduced leaf number, leaf area, dwarf phenotype and delayed seed germination. Transgenic Arabidopsis plants overexpressing BjERD4 gene also exhibited enhanced tolerance to dehydration and salt stresses, while the knockdown lines were susceptible as compared to wild type plants under similar stress conditions. It was observed that BjERD4 protein could bind RNA as evidenced by the gel-shift assay. The overall results of transcript analysis, RNA gel-shift assay, and transgenic expression, for the first time, show that the BjERD4 is involved in abiotic stress tolerance besides offering new clues about the possible roles of BjERD4 in plant growth and development. PMID:26711633

  9. Tolerance to Excess-Boron Conditions Acquired by Stabilization of a BOR1 Variant with Weak Polarity in Arabidopsis

    PubMed Central

    Wakuta, Shinji; Fujikawa, Teppei; Naito, Satoshi; Takano, Junpei

    2016-01-01

    Boron (B) is a metalloid that is essential for plant growth but is toxic when present in excess. Arabidopsis BOR1 is a borate exporter, facilitating B translocation from root to shoot under limited-B conditions. BOR1 shows stele side polar localization in the plasma membrane of various root cells, presumably to support B translocation toward the stele. BOR1 is degraded under high-B supply through vacuolar sorting via ubiquitination at the K590 residue to prevent the accumulation of B to a toxic level in shoots. A previous study showed that overexpression of BOR1 under control of the cauliflower mosaic virus 35S RNA promoter improved the growth of Arabidopsis under limited-B conditions without affecting the growth under sufficient-to-excess-B conditions. In this study, we unexpectedly found that ubiquitous expression of a stabilized BOR1 variant improved tolerance to excess-B in Arabidopsis. We established transgenic plants expressing BOR1-GFP fused with hygromycin phosphotransferase (HPT) and BOR1(K590A)-GFP-HPT under control of the ubiquitin 10 promoter. BOR1-GFP-HPT and BOR1(K590A)-GFP-HPT were expressed in various cell types in leaves and roots and showed weak polar localization in root tip cells. BOR1-GFP-HPT, but not BOR1(K590A)-GFP-HPT, was degraded through an endocytic pathway under high-B conditions. Transgenic plants with the stabilized variant BOR1(K590A)-GFP-HPT showed improved root and shoot growth under excess-B conditions. The concentration of B was greater in the shoots of plants with BOR1(K590A)-GFP-HPT or BOR1-GFP-HPT than in those of untransformed wild-type plants. These results suggest that BOR1(K590A)-GFP-HPT confers tolerance to excess-B by excluding B from the cytosol of shoot cells. Results from this study indicate the potential for engineering the trafficking properties of a transporter to produce plants that are tolerant to mineral stress. PMID:26870730

  10. Overexpression of a homopeptide repeat-containing bHLH protein gene (OrbHLH001) from Dongxiang Wild Rice confers freezing and salt tolerance in transgenic Arabidopsis.

    PubMed

    Li, Fei; Guo, Siyi; Zhao, Yuan; Chen, Dazhou; Chong, Kang; Xu, Yunyuan

    2010-09-01

    Dongxiang Wild Rice (Oryza rufipogon) is the northernmost wild rice in the world known to date and has extremely high cold tolerance and many other adversity-resistant properties. To identify the genes responsible for the high stress tolerance, we isolated and characterized a basic helix-loop-helix (bHLH) protein gene OrbHLH001 from Dongxiang Wild Rice. The gene encodes an ICE1-like protein containing multiple homopeptide repeats. Expression of OrbHLH001 is induced by salt stress and is predominant in the shoots of wild rice seedlings. Overexpression of OrbHLH001 enhanced the tolerance to freezing and salt stresses in transgenic Arabidopsis. Examination of the expression of cold-responsive genes in transgenic Arabidopsis showed that the function of OrbHLH001 differs from that of ICE1 and is independent of a CBF/DREB1 cold-response pathway. PMID:20559833

  11. 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

  12. 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

  13. Overexpression of SmLEA enhances salt and drought tolerance in Escherichia coli and Salvia miltiorrhiza.

    PubMed

    Wu, Yucui; Liu, Congling; Kuang, Jing; Ge, Qian; Zhang, Yuan; Wang, Zhezhi

    2014-09-01

    Salinity and drought are important abiotic stresses limiting plant growth and development. Late embryogenesis abundant (LEA) proteins are a group of proteins associated with tolerance to water-related stress. We previously cloned an LEA gene, SmLEA, from Salvia miltiorrhiza Bunge. Phylogenetic analysis indicated that SmLEA belongs to Group LEA14, which is involved in the dehydration response. To determine its function in detail, we have now overexpressed SmLEA in Escherichia coli and S. miltiorrhiza. The logarithmic increase in accumulations of SmLEA proteins in E. coli occurred earlier under salinity than under standard conditions. SmLEA-transformed S. miltiorrhiza plants also showed faster root elongation and a lower malondialdehyde concentration than the empty vector control plants did when cultured on MS media supplemented with 60 mM NaCl or 150 mM mannitol. Moreover, SmLEA-overexpressing transgenics experienced a less rapid rate of water loss. Under either salinity or drought, overexpressing plants had greater superoxide dismutase activity and a higher glutathione concentration. These results suggest that SmLEA may be useful in efforts to improve drought and salinity tolerance in S. miltiorrhiza. Our data also provide a good foundation for further studies into the stress resistance mechanism and molecular breeding of this valuable medicinal plant. PMID:24595620

  14. Sodium chloride toxicity and the cellular basis of salt tolerance in halophytes

    PubMed Central

    Flowers, Timothy J.; Munns, Rana; Colmer, Timothy D.

    2015-01-01

    Background Halophytes are the flora of saline soils. They adjust osmotically to soil salinity by accumulating ions and sequestering the vast majority of these (generally Na+ and Cl−) in vacuoles, while in the cytoplasm organic solutes are accumulated to prevent adverse effects on metabolism. At high salinities, however, growth is inhibited. Possible causes are: toxicity to metabolism of Na+ and/or Cl− in the cytoplasm; insufficient osmotic adjustment resulting in reduced net photosynthesis because of stomatal closure; reduced turgor for expansion growth; adverse cellular water relations if ions build up in the apoplast (cell walls) of leaves; diversion of energy needed to maintain solute homeostasis; sub-optimal levels of K+ (or other mineral nutrients) required for maintaining enzyme activities; possible damage from reactive oxygen species; or changes in hormonal concentrations. Scope This review discusses the evidence for Na+ and Cl− toxicity and the concept of tissue tolerance in relation to halophytes. Conclusions The data reviewed here suggest that halophytes tolerate cytoplasmic Na+ and Cl− concentrations of 100–200 mm, but whether these ions ever reach toxic concentrations that inhibit metabolism in the cytoplasm or cause death is unknown. Measurements of ion concentrations in the cytosol of various cell types for contrasting species and growth conditions are needed. Future work should also focus on the properties of the tonoplast that enable ion accumulation and prevent ion leakage, such as the special properties of ion transporters and of the lipids that determine membrane permeability. PMID:25466549

  15. Modest Salt Reduction Lowers Blood Pressure and Albumin Excretion in Impaired Glucose Tolerance and Type 2 Diabetes Mellitus: A Randomized Double-Blind Trial.

    PubMed

    Suckling, Rebecca J; He, Feng J; Markandu, Nirmala D; MacGregor, Graham A

    2016-06-01

    The role of salt restriction in patients with impaired glucose tolerance and diabetes mellitus is controversial, with a lack of well controlled, longer term, modest salt reduction trials in this group of patients, in spite of the marked increase in cardiovascular risk. We carried out a 12-week randomized double-blind, crossover trial of salt restriction with salt or placebo tablets, each for 6 weeks, in 46 individuals with diet-controlled type 2 diabetes mellitus or impaired glucose tolerance and untreated normal or high normal blood pressure (BP). From salt to placebo, 24-hour urinary sodium was reduced by 49±9 mmol (2.9 g salt). This reduction in salt intake led to fall in clinic BP from 136/81±2/1 mm Hg to 131/80±2/1 mm Hg, (systolic BP; P<0.01). Mean ambulatory 24-hour BP was reduced by 3/2±1/1 mm Hg (systolic BP, P<0.01 and diastolic BP, P<0.05), and albumin/creatinine ratio was reduced from 0.73 mg/mmol (0.5-1.5) to 0.64 mg/mmol (0.3-1.1; P<0.05). There was no significant change in fasting glucose, hemoglobin A1c, or insulin sensitivity. These results demonstrate that a modest reduction in salt intake, to approximately the amount recommended in public health guidelines, leads to significant and clinically relevant falls in BP in individuals who are early on in the progression of diabetes mellitus with normal or mildly raised BP. The reduction in urinary albumin excretion may carry additional benefits in reducing cardiovascular disease above the effects on BP. PMID:27160199

  16. Medawar's legacy to cellular immunology and clinical transplantation: a commentary on Billingham, Brent and Medawar (1956) 'Quantitative studies on tissue transplantation immunity. III. Actively acquired tolerance'.

    PubMed

    Simpson, Elizabeth

    2015-04-19

    'Quantitative studies on tissue transplantation immunity. III. Actively acquired tolerance', published in Philosophical Transactions B in 1956 by Peter Medawar and his colleagues, PhD graduate Leslie Brent and postdoctoral fellow Rupert Billingham, is a full description of the concept of acquired transplantation tolerance. Their 1953 Nature paper (Billingham RE et al. 1953 Nature 172, 603-606. (doi:10.1038/172603a0)) had provided initial evidence with experimental results from a small number of neonatal mice, with mention of similar findings in chicks. The Philosophical Transactions B 1956 paper is clothed with an astonishing amount of further experimental detail. It is written in Peter Medawar's landmark style: witty, perceptive and full of images that can be recalled even when details of the supporting information have faded. Those images are provided not just by a series of 20 colour plates showing skin graft recipient mice, rats, rabbits, chickens and duck, bearing fur or plumage of donor origin, but by his choice of metaphor, simile and analogy to express the questions being addressed and the interpretation of their results, along with those of relevant published data and his prescient ideas of what the results might portend. This work influenced both immunology researchers and clinicians and helped to lay the foundations for successful transplantation programmes. It led to the award of a Nobel prize in 1960 to Medawar, and subsequently to several scientists who advanced these areas. This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society. PMID:25750245

  17. Halocalculus aciditolerans gen. nov., sp. nov., an acid-tolerant haloarchaeon isolated from commercial salt.

    PubMed

    Minegishi, Hiroaki; Echigo, Akinobu; Kuwahara, Ai; Shimane, Yasuhiro; Kamekura, Masahiro; Itoh, Takashi; Ohkuma, Moriya; Usami, Ron

    2015-05-01

    Three halophilic archaeal strains, MH2-243-1(T), MH2-93-1 and MH2-91-1 were isolated from commercial salt samples from Japan, Australia, and Bolivia. Strain MH2-243-1(T) was able to grow in the presence of 12-30% (w/v) NaCl (optimum, 18% NaCl), at pH 4.5-7.0 (optimum, pH 6.0) and at 20-60 °C (optimum, 40 °C). Strains MH2-91-1 and MH2-93-1 grew in slightly different ranges. The orthologous 16S rRNA gene sequences of the three strains were almost identical (99.8-99.9% similarities), and the closest relative was Salarchaeum japonicum JCM 16327(T) with 94.2-94.3% 16S rRNA gene sequence similarities, followed by strains of members of the closely related genera Halobacterium and Halarchaeum . The RNA polymerase subunit B' gene (rpoB') sequence also showed the highest similarity (86.6%) to that of Salarchaeum japonicum JCM 16327(T). The DNA G+C contents of strains MH2-243-1(T), MH2-93-1 and MH2-91-1 were 68.5, 68.8 and 68.3 mol%, respectively. DNA-DNA relatedness values amongst the three strains were 97-99%. The polar lipids of the three strains were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, and at least seven unidentified glycolipids. The polar lipid composition differed from those of Salarchaeum japonicum and species of the genera Halobacterium and Halarchaeum . Based on the phenotypic and phylogenetic analyses, it is proposed that the isolates represent a novel species of a new genus, for which the name Halocalculus aciditolerans gen. nov., sp. nov. is proposed. The type strain of the type species is MH2-243-1(T) ( = JCM 19596(T) =KCTC 4149(T)) isolated from solar salt produced in Japan. MH2-93-1 ( = JCM 19595) and MH2-91-1 ( = JCM 19594) are additional strains of the type species. PMID:25721724

  18. A novel cold-adapted and highly salt-tolerant esterase from Alkalibacterium sp. SL3 from the sediment of a soda lake.

    PubMed

    Wang, Guozeng; Wang, Qiaohuang; Lin, Xianju; Ng, Tzi Bun; Yan, Renxiang; Lin, Juan; Ye, Xiuyun

    2016-01-01

    A novel esterase gene (estSL3) was cloned from the Alkalibacterium sp. SL3, which was isolated from the sediment of soda lake Dabusu. The 636-bp full-length gene encodes a polypeptide of 211 amino acid residues that is closely related with putative GDSL family lipases from Alkalibacterium and Enterococcus. The gene was successfully expressed in E. coli, and the recombinant protein (rEstSL3) was purified to electrophoretic homogeneity and characterized. rEstSL3 exhibited the highest activity towards pNP-acetate and had no activity towards pNP-esters with acyl chains longer than C8. The enzyme was highly cold-adapted, showing an apparent temperature optimum of 30 °C and remaining approximately 70% of the activity at 0 °C. It was active and stable over the pH range from 7 to 10, and highly salt-tolerant up to 5 M NaCl. Moreover, rEstSL3 was strongly resistant to most tested metal ions, chemical reagents, detergents and organic solvents. Amino acid composition analysis indicated that EstSL3 had fewer proline residues, hydrogen bonds and salt bridges than mesophilic and thermophilic counterparts, but more acidic amino acids and less hydrophobic amino acids when compared with other salt-tolerant esterases. The cold active, salt-tolerant and chemical-resistant properties make it a promising enzyme for basic research and industrial applications. PMID:26915906

  19. A maize mitogen-activated protein kinase kinase, ZmMKK1, positively regulated the salt and drought tolerance in transgenic Arabidopsis.

    PubMed

    Cai, Guohua; Wang, Guodong; Wang, Li; Liu, Yang; Pan, Jiaowen; Li, Dequan

    2014-07-15

    Mitogen-activated protein kinase (MAPK) cascades are highly conserved signal transduction modules in animals, plants and yeast. MAPK cascades are complicated networks and play vital roles in signal transduction pathways involved in biotic and abiotic stresses. In this study, a maize MAPKK gene, ZmMKK1, was characterized. Quantitative real time PCR (qRT-PCR) analysis demonstrated that ZmMKK1 transcripts were induced by diverse stresses and ABA signal molecule in maize root. Further study showed that the ZmMKK1-overexpressing Arabidopsis enhanced the tolerance to salt and drought stresses. However, seed germination, post-germination growth and stomatal aperture analysis demonstrated that ZmMKK1 overexpression was sensitive to ABA in transgenic Arabidopsis. Molecular genetic analysis revealed that the overexpression of ZmMKK1 in Arabidopsis enhanced the expression of ROS scavenging enzyme- and ABA-related genes, such as POD, CAT, RAB18 and RD29A under salt and drought conditions. In addition, heterologous overexpression of ZmMKK1 in yeast (Saccharomyces cerevisiae) improved the tolerance to salt and drought stresses. These results suggested that ZmMKK1 might act as an ABA- and ROS-dependent protein kinase in positive modulation of salt and drought tolerance. Most importantly, ZmMKK1 interacted with ZmMEKK1 as evidenced by yeast two-hybrid assay, redeeming a deficiency of MAPK interaction partners in maize. PMID:24974327

  20. A novel cold-adapted and highly salt-tolerant esterase from Alkalibacterium sp. SL3 from the sediment of a soda lake

    PubMed Central

    Wang, Guozeng; Wang, Qiaohuang; Lin, Xianju; Bun Ng, Tzi; Yan, Renxiang; Lin, Juan; Ye, Xiuyun

    2016-01-01

    A novel esterase gene (estSL3) was cloned from the Alkalibacterium sp. SL3, which was isolated from the sediment of soda lake Dabusu. The 636-bp full-length gene encodes a polypeptide of 211 amino acid residues that is closely related with putative GDSL family lipases from Alkalibacterium and Enterococcus. The gene was successfully expressed in E. coli, and the recombinant protein (rEstSL3) was purified to electrophoretic homogeneity and characterized. rEstSL3 exhibited the highest activity towards pNP-acetate and had no activity towards pNP-esters with acyl chains longer than C8. The enzyme was highly cold-adapted, showing an apparent temperature optimum of 30 °C and remaining approximately 70% of the activity at 0 °C. It was active and stable over the pH range from 7 to 10, and highly salt-tolerant up to 5 M NaCl. Moreover, rEstSL3 was strongly resistant to most tested metal ions, chemical reagents, detergents and organic solvents. Amino acid composition analysis indicated that EstSL3 had fewer proline residues, hydrogen bonds and salt bridges than mesophilic and thermophilic counterparts, but more acidic amino acids and less hydrophobic amino acids when compared with other salt-tolerant esterases. The cold active, salt-tolerant and chemical-resistant properties make it a promising enzyme for basic research and industrial applications. PMID:26915906

  1. Over-expression of the peroxisomal ascorbate peroxidase (SbpAPX) gene cloned from halophyte Salicornia brachiata confers salt and drought stress tolerance in transgenic tobacco.

    PubMed

    Singh, Natwar; Mishra, Avinash; Jha, Bhavanath

    2014-06-01

    Salicornia brachiata Roxb., an extreme halophyte, is a naturally adapted higher plant model for additional gene resources to engineer salt tolerance in plants. Ascorbate peroxidase (APX) plays a key role in protecting plants against oxidative stress and thus confers abiotic stress tolerance. A full-length SbpAPX cDNA, encoding peroxisomal ascorbate peroxidase, was cloned from S. brachiata. The open reading frame encodes for a polypeptide of 287 amino acid residues (31.3-kDa protein). The deduced amino acid sequence of the SbpAPX gene showed characteristic peroxisomal targeting sequences (RKRAI) and a C-terminal hydrophobic region of 39 amino acid residues containing a transmembrane domain (TMD) of 23 amino acid residues. Northern blot analysis showed elevated SbpAPX transcript in response to salt, cold, abscisic acid and salicylic acid stress treatments. The SbpAPX gene was transformed to tobacco for their functional validation under stresses. Transgenic plants over-expressing SbpAPX gene showed enhanced salt and drought stress tolerance compared to wild-type plants. Transgenic plants showed enhanced vegetative growth and germination rate both under normal and stressed conditions. Present study revealed that the SbpAPX gene is a potential candidate, which not only confers abiotic stress tolerance to plants but also seems to be involved in plant growth. PMID:24197564

  2. OsCCD1, a novel small calcium-binding protein with one EF-hand motif, positively regulates osmotic and salt tolerance in rice.

    PubMed

    Jing, Pei; Zou, Juanzi; Kong, Lin; Hu, Shiqi; Wang, Biying; Yang, Jun; Xie, Guosheng

    2016-06-01

    Calcium-binding proteins play key roles in the signal transduction in the growth and stress response in eukaryotes. However, a subfamily of proteins with one EF-hand motif has not been fully studied in higher plants. Here, a novel small calcium-binding protein with a C-terminal centrin-like domain (CCD1) in rice, OsCCD1, was characterized to show high similarity with a TaCCD1 in wheat. As a result, OsCCD1 can bind Ca(2+) in the in vitro EMSA and the fluorescence staining calcium-binding assays. Transient expression of green fluorescent protein (GFP)-tagged OsCCD1 in rice protoplasts showed that OsCCD1 was localized in the nucleus and cytosol of rice cells. OsCCD1 transcript levels were transiently induced by osmotic stress and salt stress through the calcium-mediated ABA signal. The rice seedlings of T-DNA mutant lines showed significantly less tolerance to osmotic and salt stresses than wild type plants (p<0.01). Conversely, its overexpressors can significantly enhance the tolerance to osmotic and salt stresses than wild type plants (p<0.05). Semi-quantitative RT-PCR analysis revealed that, OsDREB2B, OsAPX1 and OsP5CS genes are involved in the rice tolerance to osmotic and salt stresses. In sum, OsCCD1 gene probably affects the DREB2B and its downstream genes to positively regulate osmotic and salt tolerance in rice seedlings. PMID:27095404

  3. Tolerance of spring wheat to a salt-fluxing residue containing potassium and magnesium

    SciTech Connect

    Mahler, R.L.; Menser, H.A.; Lutcher, L.K.

    1986-01-01

    Field and greenhouse studies were conducted in Idaho in 1985 to document the maximum levels of a salt fluxing residue (slag) material that can be safely applied to agricultural soils without reducing spring wheat (Triticum aestivum) growth. The slag material, which contains significant quantities of Mg and K, was applied to Mission (coarse-silty, mixed, frigid Andic Fragiochrepts) and Palouse (fine-silty, mixed, mesic Pachic Ultic Haploxerolls) silt loam soils at rates ranging from 0 to 40,000 kg/ha. Parameters evaluated included: (1) germination, (2) plant vigor, (3) yield, and (4) soil and plant tissue K, Ca and Mg. Under field conditions slag application rates of 4000 and 8000 kg/ha reduced wheat stands and vigor; however, yields were not adversely affected when compared with the control. Application rates in excess of 8000 kg/ha resulted in reduced germination, plant vigor, and yield and are consequently not recommended. Greenhouse studies provided further evidence to substantiate the field results.

  4. Halophilic Bacteria of Lunsu Produce an Array of Industrially Important Enzymes with Salt Tolerant Activity.

    PubMed

    Gupta, Sonika; Sharma, Parul; Dev, Kamal; Sourirajan, Anuradha

    2016-01-01

    The halophilic bacterial isolates SS1, SS2, SS3, SS5, and SS8 were characterized for production of industrially important enzymes like amylase, protease, lipase, and glutaminase. Halophilic bacterial isolates SS1 and SS3 exhibited salt dependent extracellular amylase and protease activities. Both the halophilic isolates SS1 and SS3 exhibited maximum amylase and protease activities in the presence of 1.5 and 1.0 M NaCl, respectively, with the optimum pH 8 and temperature 40°C. SS2 showed maximum extracellular protease and lipase activities in the presence of 0.75 M NaCl, at optimum pH of 7, and temperature 37°C. The glutaminase activity of SS3 increased with increase in concentration of NaCl up to 2.5 M. The optimum pH and temperature for L-glutaminase activity of SS3 was 8 and 40°C, respectively. The combined hydrolytic activities of these halophilic bacterial isolates can be used for bioconversion of organic materials to useful products. PMID:26885394

  5. Halophilic Bacteria of Lunsu Produce an Array of Industrially Important Enzymes with Salt Tolerant Activity

    PubMed Central

    Gupta, Sonika; Sharma, Parul; Dev, Kamal; Sourirajan, Anuradha

    2016-01-01

    The halophilic bacterial isolates SS1, SS2, SS3, SS5, and SS8 were characterized for production of industrially important enzymes like amylase, protease, lipase, and glutaminase. Halophilic bacterial isolates SS1 and SS3 exhibited salt dependent extracellular amylase and protease activities. Both the halophilic isolates SS1 and SS3 exhibited maximum amylase and protease activities in the presence of 1.5 and 1.0 M NaCl, respectively, with the optimum pH 8 and temperature 40°C. SS2 showed maximum extracellular protease and lipase activities in the presence of 0.75 M NaCl, at optimum pH of 7, and temperature 37°C. The glutaminase activity of SS3 increased with increase in concentration of NaCl up to 2.5 M. The optimum pH and temperature for L-glutaminase activity of SS3 was 8 and 40°C, respectively. The combined hydrolytic activities of these halophilic bacterial isolates can be used for bioconversion of organic materials to useful products. PMID:26885394

  6. Allergenicity assessment of genetically-modified tobacco expressing salt tolerance cbl gene.

    PubMed

    Verma, Alok Kumar; Kumar, Sandeep; Chaudhari, Bhushan P; Tuteja, Narendra; Das, Mukul; Dwivedi, Premendra D

    2014-09-01

    It is mandatory to assess the allergenic potential of genetically modified (GM) crops before their commercialization. Recently, a transgene [Calcineurin B-like (CBL) protein] has been introduced into tobacco plant to make the crop salt resistance. Therefore, it was felt necessary to assess the allergenic potential of the cbl gene product, which was introduced and expressed in Nicotiana tabacum (tobacco) plant and compared the allergenic effects with the wild-type (WT) counterpart. Bioinformatic analysis revealed that there was no significant sequence homology with known allergens. Also, no difference between the protein digestibility profiles of GM and WT tobacco was found. Rapid digestion of CBL protein (Mol Wt 35 kDa) by simulated gastric fluid (SGF) indicated reduced chances of this protein to induce allergenicity. In addition, BALB/c mice sensitized by intraperitoneal administration of WT and GM tobacco protein showed comparable levels of clinical score, specific IgE, IgG1, histamine level, similar effect on different organs as well as IgE binding proteins. These findings indicate that insertion of cbl gene in tobacco did not cause any additional allergic risk to consumer and the GM and native tobacco proteins behave similarly in both in vitro and in vivo situations even after genetic modification. PMID:25106468

  7. Overexpression of Rice NAC Gene SNAC1 Improves Drought and Salt Tolerance by Enhancing Root Development and Reducing Transpiration Rate in Transgenic Cotton

    PubMed Central

    Liu, Guanze; Li, Xuelin; Jin, Shuangxia; Liu, Xuyan; Zhu, Longfu; Nie, Yichun; Zhang, Xianlong

    2014-01-01

    The SNAC1 gene belongs to the stress-related NAC superfamily of transcription factors. It was identified from rice and overexpressed in cotton cultivar YZ1 by Agrobacterium tumefaciens-mediated transformation. SNAC1-overexpressing cotton plants showed more vigorous growth, especially in terms of root development, than the wild-type plants in the presence of 250 mM NaCl under hydroponic growth conditions. The content of proline was enhanced but the MDA content was decreased in the transgenic cotton seedlings under drought and salt treatments compared to the wild-type. Furthermore, SNAC1-overexpressing cotton plants also displayed significantly improved tolerance to both drought and salt stresses in the greenhouse. The performances of the SNAC1-overexpressing lines under drought and salt stress were significantly better than those of the wild-type in terms of the boll number. During the drought and salt treatments, the transpiration rate of transgenic plants significantly decreased in comparison to the wild-type, but the photosynthesis rate maintained the same at the flowering stage in the transgenic plants. These results suggested that overexpression of SNAC1 improve more tolerance to drought and salt in cotton through enhanced root development and reduced transpiration rates. PMID:24489802

  8. Tolerance to cadmium and cadmium-binding ligands in Great Salt Lake brine shrimp (Artemia salina)

    SciTech Connect

    Jayasekara, S.; Drown, D.B.; Sharma, R.P.

    1986-02-01

    Information on the accumulation of cadmium in cytosolic proteins of Great Lake brine shrimp (Artemia salina) was obtained from animals collected directly from the lake and also from animal hatched and maintained in three sublethal concentrations of cadmium (0.5, 2.0, 5.0 ppm) in saltwater aquaria. Brine shrimp growth under these conditions was monitored by measuring body lengths during a 7-day exposure period. Heat-stable, cadmium-binding ligands were isolated and identified by Sephadex G-75 chromatography and atomic absorption spectrophotometry. Cadmium was found to be equally distributed between high and low molecular weight proteins in animals collected from the lake and the 0.5 ppm cadmium group. There was also a slight growth stimulation noted in the 0.5-pm group. Higher cadmium incorporation was noted in low molecular weight fractions with increasing cadmium concentration in the exposure media. Low molecular weight fractions were also found to have high uv absorption characteristics at 250 nm and low absorption at 280 nm. Molecular weight of the cadmium-binding ligands was found to be 11,000 as estimated by the gel filtration method. De novo synthesis of this protein was increased as a function of cadmium concentration in the media. However, slow accumulation of cadmium in other protein fractions was also noticed in higher cadmium exposure groups, suggesting the existence of possible tolerance mechanisms in brine shrimp exposed to suspected acute cadmium concentrations.

  9. Characterization of a novel cold active and salt tolerant esterase from Zunongwangia profunda.

    PubMed

    Rahman, Mohammad Asadur; Culsum, Umma; Tang, Wenhao; Zhang, Shao Wei; Wu, Gaobing; Liu, Ziduo

    2016-04-01

    A novel cold active esterase, EstLiu was cloned from the marine bacterium Zunongwangia profunda, overexpressed in E. coli BL21 (DE3) and purified by glutathione-S transferase (GST) affinity chromatography. The mature esterase EstLiu sequence encodes a protein of 273 amino acids residues, with a predicted molecular weight of 30KDa and containing the classical pentapeptidase motif from position 156 to 160 with the catalytic triad Ser158-Asp211-His243. Although, EstLiu showed 64% similarity with the hypothetical esterase from Chryseobacterium sp. StRB126 (WP_045498424), phylogenetic analysis showed it had no similarity with any of the established family of lipases/esterases, suggesting that it could be considered as a new family. The purified enzyme showed broad substrate specificity with the highest hydrolytic activity against p-nitrophenyl butyrate (C4). EstLiu showed remarkable activity (75%) at 0°Cand the optimal activity at pH 8.0 and 30°C with good thermostability and quickened inactivation above 60°C. EstLiu retained 81, 103, 67 and 78% of its original activity at 50% (v/v) in ethanol, isopropanol, DMSO and ethylene glycol, respectively. In the presence of Tween 20, Tween 80 and Triton X-100, EstLiu showed 88, 100 and 117% of relative activity. It is also co-factor independent. The high activity at low temperature and desirable stability in organic solvents and salts of this novel family esterase represents a good evidence of novel biocatalyst. Overall, this novel enzyme showed better activity than previously reported esterases in extreme reaction conditions and could promote the reaction in both aqueous and non-aqueous conditions, indicating its great potential for industrial applications. PMID:26920474

  10. Low-temperature-active and salt-tolerant β-mannanase from a newly isolated Enterobacter sp. strain N18.

    PubMed

    You, Jia; Liu, Jin-Feng; Yang, Shi-Zhong; Mu, Bo-Zhong

    2016-02-01

    A low-temperature-active and salt-tolerant β-mannanase produced by a novel mannanase-producer, Enterobacter sp. strain N18, was isolated, purified and then evaluated for its potential application as a gel-breaker in relation to viscosity reduction of guar-based hydraulic fracturing fluids used in oil field. The enzyme could lower the viscosity of guar gum solution by more than 95% within 10 min. The purified β-mannanase with molecular mass of 90 kDa displayed high activity in a broad range of pH and temperature: more than 70% of activity was retained in the pH range of 3.0-8.0 with the optimal pH 7.5, about 50% activity at 20°C with the optimal temperature 50°C. Furthermore, the enzyme retained >70% activity in the presence of 0.5-4.0 M NaCl. These properties implied that the enzyme from strain N18 had potential for serving as a gel-breaker for low temperature oil wells and other industrial fields, where chemical gel breakers were inactive due to low temperature. PMID:26168907

  11. Potassium sensitivity differs among strains of the harmful cyanobacterium Microcystis and correlates with the presence of salt tolerance genes.

    PubMed

    Sandrini, Giovanni; Huisman, Jef; Matthijs, Hans C P

    2015-08-01

    Microcystis aeruginosa is a ubiquitous harmful cyanobacterium that causes problems in eutrophic lakes. Potassium ion (K(+)) addition is one of the suggested methods to combat harmful cyanobacterial blooms. To investigate the effectiveness of this method, we compared the potassium ion sensitivity of four Microcystis strains. Microcystis strains PCC 7005 and NIES-843 were very susceptible to potassium ion concentrations of ∼ 12 mmol L(-1), whereas strain PCC 7806 and its non-toxic mutant PCC 7806 ΔmcyB were not affected by added potassium ions. The origin of the strain appears to be of importance. Strain PCC 7806 originates from brackish water and possesses genes for the synthesis of the compatible solute sucrose, the water channel protein gene aqpZ and the sodium influx gene nhaS2, whereas strains PCC 7005 and NIES-843 have a freshwater origin and lack these genes. We conclude that potassium ion addition will not be a successful mitigation strategy in brackish waters, but may temporarily suppress Microcystis blooms in freshwater lakes. However, in the long run other Microcystis strains or other cyanobacteria with a higher salt tolerance will likely take over. In addition, our results also have implications for the potassium ion concentrations of mineral media used in laboratory studies with cyanobacteria. PMID:26208527

  12. 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

  13. 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

  14. K+ Efflux and Retention in Response to NaCl Stress Do Not Predict Salt Tolerance in Contrasting Genotypes of Rice (Oryza sativa L.)

    PubMed Central

    Coskun, Devrim; Britto, Dev T.; Jean, Yuel-Kai; Kabir, Imtiaz; Tolay, Inci; Torun, Ayfer A.; Kronzucker, Herbert J.

    2013-01-01

    Sudden elevations in external sodium chloride (NaCl) accelerate potassium (K+) efflux across the plasma membrane of plant root cells. It has been proposed that the extent of this acceleration can predict salt tolerance among contrasting cultivars. However, this proposal has not been considered in the context of plant nutritional history, nor has it been explored in rice (Oryza sativa L.), which stands among the world’s most important and salt-sensitive crop species. Using efflux analysis with 42K, coupled with growth and tissue K+ analyses, we examined the short- and long-term effects of NaCl exposure to plant performance within a nutritional matrix that significantly altered tissue-K+ set points in three rice cultivars that differ in salt tolerance: IR29 (sensitive), IR72 (moderate), and Pokkali (tolerant). We show that total short-term K+ release from roots in response to NaCl stress is small (no more than 26% over 45 min) in rice. Despite strong varietal differences, the extent of efflux is shown to be a poor predictor of plant performance on long-term NaCl stress. In fact, no measure of K+ status was found to correlate with plant performance among cultivars either in the presence or absence of NaCl stress. By contrast, shoot Na+ accumulation showed the strongest correlation (a negative one) with biomass, under long-term salinity. Pharmacological evidence suggests that NaCl-induced K+ efflux is a result of membrane disintegrity, possibly as result of osmotic shock, and not due to ion-channel mediation. Taken together, we conclude that, in rice, K+ status (including efflux) is a poor predictor of salt tolerance and overall plant performance and, instead, shoot Na+ accumulation is the key factor in performance decline on NaCl stress. PMID:23460903

  15. Permanent Draft Genome Sequence of Frankia sp. Strain Allo2, a Salt-Tolerant Nitrogen-Fixing Actinobacterium Isolated from the Root Nodules of Allocasuarina

    PubMed Central

    Oshone, Rediet; Ngom, Mariama; Abebe-Akele, Feseha; Simpson, Stephen; Morris, Krystalynne; Sy, Mame Ourèye; Champion, Antony; Thomas, W. Kelley

    2016-01-01

    Frankia sp. strain Allo2 is a member of Frankia lineage Ib, which is able to reinfect plants of the Casuarinaceae family, and exhibits a high level of salt tolerance compared to other isolates. Here, we report the 5.3-Mbp draft genome sequence of Frankia sp. strain Allo2 with a G+C content of 70.0% and 4,224 candidate protein-encoding genes. PMID:27198023

  16. Permanent Draft Genome Sequence of Frankia sp. Strain Allo2, a Salt-Tolerant Nitrogen-Fixing Actinobacterium Isolated from the Root Nodules of Allocasuarina.

    PubMed

    Oshone, Rediet; Ngom, Mariama; Abebe-Akele, Feseha; Simpson, Stephen; Morris, Krystalynne; Sy, Mame Ourèye; Champion, Antony; Thomas, W Kelley; Tisa, Louis S

    2016-01-01

    Frankia sp. strain Allo2 is a member of Frankia lineage Ib, which is able to reinfect plants of the Casuarinaceae family, and exhibits a high level of salt tolerance compared to other isolates. Here, we report the 5.3-Mbp draft genome sequence of Frankia sp. strain Allo2 with a G+C content of 70.0% and 4,224 candidate protein-encoding genes. PMID:27198023

  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 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

  18. Grapevine and Arabidopsis Cation-Chloride Cotransporters Localize to the Golgi and Trans-Golgi Network and Indirectly Influence Long-Distance Ion Transport and Plant Salt Tolerance.

    PubMed

    Henderson, Sam W; Wege, Stefanie; Qiu, Jiaen; Blackmore, Deidre H; Walker, Amanda R; Tyerman, Stephen D; Walker, Rob R; Gilliham, Matthew

    2015-11-01

    Plant cation-chloride cotransporters (CCCs) have been implicated in conferring salt tolerance. They are predicted to improve shoot salt exclusion by directly catalyzing the retrieval of sodium (Na(+)) and chloride (Cl(-)) ions from the root xylem. We investigated whether grapevine (Vitis vinifera [Vvi]) CCC has a role in salt tolerance by cloning and functionally characterizing the gene from the cultivar Cabernet Sauvignon. Amino acid sequence analysis revealed that VviCCC shares a high degree of similarity with other plant CCCs. A VviCCC-yellow fluorescent protein translational fusion protein localized to the Golgi and the trans-Golgi network and not the plasma membrane when expressed transiently in tobacco (Nicotiana benthamiana) leaves and Arabidopsis (Arabidopsis thaliana) mesophyll protoplasts. AtCCC-green fluorescent protein from Arabidopsis also localized to the Golgi and the trans-Golgi network. In Xenopus laevis oocytes, VviCCC targeted to the plasma membrane, where it catalyzed bumetanide-sensitive (36)Cl(-), (22)Na(+), and (86)Rb(+) uptake, suggesting that VviCCC (like AtCCC) belongs to the Na(+)-K(+)-2Cl(-) cotransporter class of CCCs. Expression of VviCCC in an Arabidopsis ccc knockout mutant abolished the mutant's stunted growth phenotypes and reduced shoot Cl(-) and Na(+) content to wild-type levels after growing plants in 50 mm NaCl. In grapevine roots, VviCCC transcript abundance was not regulated by Cl(-) treatment and was present at similar levels in both the root stele and cortex of three Vitis spp. genotypes that exhibit differential shoot salt exclusion. Our findings indicate that CCC function is conserved between grapevine and Arabidopsis, but neither protein is likely to directly mediate ion transfer with the xylem or have a direct role in salt tolerance. PMID:26378102

  19. 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

  20. Dwarf apple MbDREB1 enhances plant tolerance to low temperature, drought, and salt stress via both ABA-dependent and ABA-independent pathways.

    PubMed

    Yang, Wei; Liu, Xiao-Dan; Chi, Xiao-Juan; Wu, Chang-Ai; Li, Yan-Ze; Song, Li-Li; Liu, Xiu-Ming; Wang, Yan-Fang; Wang, Fa-Wei; Zhang, Chuang; Liu, Yang; Zong, Jun-Mei; Li, Hai-Yan

    2011-02-01

    In higher plants, DREB1/CBF-type transcription factors play an important role in tolerance to low temperatures, drought, and high-salt stress. These transcription factors bind to CRT/DRE elements in promoter regions of target genes, regulating their expression. In this study, we cloned and characterized a novel gene encoding a DREB1 transcription factor from dwarf apple, Malus baccata (GenBank accession number: EF582842). Expression of MbDREB1 was induced by cold, drought, and salt stress, and also in response to exogenous ABA. Subcellular localization analyses revealed that MbDREB1 localizes in the nucleus. A yeast activity assay demonstrated that the MbDREB1 gene encodes a transcription activator, which specifically binds to DRE/CRT elements. Compared with wild-type plants, transgenic Arabidopsis overexpressing MbDREB1 showed increased tolerance to low temperature, drought, and salt stresses. Analysis of the MbDREB1 promoter revealed an ABA-responsive element (ABRE), an inducer of CBF expression 1 (ICE1)-like binding site, two MYB recognition sites, and three stress-inducible GT-1 boxes. GUS activities driven by the MbDREB1 promoter in transgenic Arabidopsis increased in response to ABA, cold temperature, drought, and salt treatments. Interestingly, the expression of both ABA-independent and ABA-dependent stress-induced genes (COR15a and rd29B, respectively) was activated under normal growth conditions in Arabidopsis overexpressing MbDREB1. These results suggest that MbDREB1 functions as a transcription factor and increases plant tolerance to low temperature, drought, and salt stress via both ABA-dependent and ABA-independent pathways. PMID:20967459

  1. MusaDHN-1, a novel multiple stress-inducible SK(3)-type dehydrin gene, contributes affirmatively to drought- and salt-stress tolerance in banana.

    PubMed

    Shekhawat, Upendra K Singh; Srinivas, Lingam; Ganapathi, Thumballi R

    2011-11-01

    Dehydrins are highly hydrophilic proteins involved in playing key adaptive roles in response to abiotic stress conditions having dehydration as a common component. In the present study, a novel banana SK(3)-type dehydrin, MusaDHN-1, was identified and later characterized using transgenic banana plants to investigate its functions in abiotic stress tolerance. Expression profiling in native banana plants demonstrated that MusaDHN-1 was induced in leaves by drought, salinity, cold, oxidative and heavy metal stress as well as by treatment with signalling molecules like abscisic acid, ethylene and methyl jasmonate. Promoter analysis carried out by making a MusaDHN-1 promoter: β-glucuronidase fusion construct reconfirmed the abiotic stress inducibility of MusaDHN-1. Transgenic banana plants constitutively overexpressing MusaDHN-1 were phenotypically normal and displayed improved tolerance to drought and salt-stress treatments in both in vitro and ex vitro assays. Enhanced accumulation of proline and reduced malondialdehyde levels in drought and salt-stressed MusaDHN-1 overexpressing plants further established their superior performance in stressed conditions. This study is the first to report generation of transgenic banana plants engineered for improved drought and salt-stress tolerance. PMID:21671068

  2. A Remorin Gene SiREM6, the Target Gene of SiARDP, from Foxtail Millet (Setaria italica) Promotes High Salt Tolerance in Transgenic Arabidopsis

    PubMed Central

    Liu, Yuwei; Yu, Jingjuan

    2014-01-01

    Remorin proteins (REMs) form a plant-specific protein family, with some REMs being responsive to abiotic stress. However, the precise functions of REMs in abiotic stress tolerance are not clear. In this study, we identified 11 remorin genes from foxtail millet (Setaria italica) and cloned a remorin gene, SiREM6, for further investigation. The transcript level of SiREM6 was increased by high salt stress, low temperature stress and abscisic acid (ABA) treatment, but not by drought stress. The potential oligomerization of SiREM6 was examined by negative staining electron microscopy. The overexpression of SiREM6 improved high salt stress tolerance in transgenic Arabidopsis at the germination and seedling stages as revealed by germination rate, survival rate, relative electrolyte leakage and proline content. The SiREM6 promoter contains two dehydration responsive elements (DRE) and one ABA responsive element (ABRE). An ABA responsive DRE-binding transcription factor, SiARDP, and an ABRE-binding transcription factor, SiAREB1, were cloned from foxtail millet. SiARDP could physically bind to the DREs, but SiAREB1 could not. These results revealed that SiREM6 is a target gene of SiARDP and plays a critical role in high salt stress tolerance. PMID:24967625

  3. A ginseng PgTIP1 gene whose protein biological activity related to Ser(128) residue confers faster growth and enhanced salt stress tolerance in Arabidopsis.

    PubMed

    Li, Jia; Cai, Weiming

    2015-05-01

    Water movement across cellular membranes is mostly regulated by aquaporins. A tonoplast intrinsic protein PgTIP1 from Panax ginseng has been found to play an important role in plant growth and development, and also in the response of plants to abiotic stress. However, the regulation of its function and activity remains unknown. To answer this question, mutated forms of PgTIP1 were made by replacing Ser(128) with Ala (named S128A) or Asp (named S128D), and also by replacing Thr(54) with Ala (named T54A) or Asp (named T54D). Then, wild type or mutated PgTIP1 was expressed in yeast and water transport was monitored in protoplasts. The substitution of Ser(128) abolished the water channel activity of PgTIP1, while the substitution of Thr(54) did not inhibit its activity. Moreover, the overexpression of PgTIP1 but not S128A or S128D in Arabidopsis significantly increased plant growth as determined by biomass production, it also had a beneficial effect on salt stress tolerance. Importantly, the overexpression of PgTIP1 led to the altered expression of stress-related genes, which made the plants more tolerant to salt stress. Our results demonstrated that PgTIP1 conferred faster growth and enhanced tolerance to salt in Arabidopsis, and that its biological activity related to Ser(128) residue. PMID:25804811

  4. Constitutive and stress-inducible overexpression of a native aquaporin gene (MusaPIP2;6) in transgenic banana plants signals its pivotal role in salt tolerance.

    PubMed

    Sreedharan, Shareena; Shekhawat, Upendra K Singh; Ganapathi, Thumballi R

    2015-05-01

    High soil salinity constitutes a major abiotic stress and an important limiting factor in cultivation of crop plants worldwide. Here, we report the identification and characterization of a aquaporin gene, MusaPIP2;6 which is involved in salt stress signaling in banana. MusaPIP2;6 was firstly identified based on comparative analysis of stressed and non-stressed banana tissue derived EST data sets and later overexpression in transgenic banana plants was performed to study its tangible functions in banana plants. The overexpression of MusaPIP2;6 in transgenic banana plants using constitutive or inducible promoter led to higher salt tolerance as compared to equivalent untransformed control plants. Cellular localization assay performed using transiently transformed onion peel cells indicated that MusaPIP2;6 protein tagged with green fluorescent protein was translocated to the plasma membrane. MusaPIP2;6-overexpressing banana plants displayed better photosynthetic efficiency and lower membrane damage under salt stress conditions. Our results suggest that MusaPIP2;6 is involved in salt stress signaling and tolerance in banana. PMID:25757388

  5. Co-transforming bar and CsLEA enhanced tolerance to drought and salt stress in transgenic alfalfa (Medicago sativa L.).

    PubMed

    Zhang, Jiyu; Duan, Zhen; Zhang, Daiyu; Zhang, Jianquan; Di, Hongyan; Wu, Fan; Wang, Yanrong

    2016-03-25

    Drought and high salinity are two major abiotic factors that restrict alfalfa productivity. A dehydrin protein, CsLEA, from the desert grass Cleistogenes songorica was transformed into alfalfa (Medicago sativa L.) via Agrobacterium-mediated transformation using the bar gene as a selectable marker, and the drought and salt stress tolerances of the transgenic plants were assessed. Thirty-nine of 119 transformants were positive, as screened by Basta, and further molecularly authenticated using PCR and RT-PCR. Phenotype observations revealed that the transgenic plants grew better than the wild-type (WT) plants after 15d of drought stress and 10d of salt stress: the leaves of WT alfalfa turned yellow, whereas the transgenic alfalfa leaves only wilted; after rewatering, the transgenic plants returned to a normal state, though the WT plants could not be restored. Evaluation of physiologic and biochemical indices during drought and salt stresses showed a relatively lower Na(+) content in the leaves of the transgenic plants, which would reduce toxic ion effects. In addition, the transgenic plants were able to maintain a higher relative water content (RWC), higher shoot biomass, fewer photosystem changes, decreased membrane injury, and a lower level of osmotic stress injury. These results demonstrate that overexpression of the CsLEA gene can enhance the drought and salt tolerance of transgenic alfalfa; in addition, carrying the bar gene in the genome may increase herbicide resistance. PMID:26906624

  6. Ectopic over-expression of peroxisomal ascorbate peroxidase (SbpAPX) gene confers salt stress tolerance in transgenic peanut (Arachis hypogaea).

    PubMed

    Singh, Natwar; Mishra, Avinash; Jha, Bhavanath

    2014-08-15

    Peroxisomal ascorbate peroxidase gene (SbpAPX) of an extreme halophyte Salicornia brachiata imparts abiotic stress endurance and plays a key role in the protection against oxidative stress. The cloned SbpAPX gene was transformed to local variety of peanut and about 100 transgenic plants were developed using optimized in vitro regeneration and Agrobacterium mediated genetic transformation method. The T0 transgenic plants were confirmed for the gene integration; grown under controlled condition in containment green house facility; seeds were harvested and T1 plants were raised. Transgenic plants (T1) were further confirmed by PCR using gene specific primers and histochemical GUS assay. About 40 transgenic plants (T1) were selected randomly and subjected for salt stress tolerance study. Transgenic plants remained green however non-transgenic plants showed bleaching and yellowish leaves under salt stress conditions. Under stress condition, transgenic plants continued normal growth and completed their life cycle. Transgenic peanut plants exhibited adequate tolerance under salt stress condition and thus could be explored for the cultivation in salt affected areas for the sustainable agriculture. PMID:24954532

  7. Salt tolerance and osmotic adjustment of Spartina alterniflora (Poaceae) and the invasive M haplotype of Phragmites australis (Poaceae) along a salinity gradient

    USGS Publications Warehouse

    Vasquez, E.A.; Glenn, E.P.; Guntenspergen, G.R.; Brown, J.J.; Nelson, S.G.

    2006-01-01

    An invasive variety of Phragmites australis (Poaceae, common reed), the M haplotype, has been implicated in the spread of this species into North American salt marshes that are normally dominated by the salt marsh grass Spartina alterniflora (Poaceae, smooth cordgrass). In some European marshes, on the other hand, Spartina spp. derived from S. alterniflora have spread into brackish P. australis marshes. In both cases, the non-native grass is thought to degrade the habitat value of the marsh for wildlife, and it is important to understand the physiological processes that lead to these species replacements. We compared the growth, salt tolerance, and osmotic adjustment of M haplotype P. australis and S. alterniflora along a salinity gradient in greenhouse experiments. Spartina alterniflora produced new biomass up to 0.6 M NaCl, whereas P. australis did not grow well above 0.2 M NaCl. The greater salt tolerance of S. alterniflora compared with P. australis was due to its ability to use Na+ for osmotic adjustment in the shoots. On the other hand, at low salinities P. australis produced more shoots per gram of rhizome tissue than did S. alterniflora. This study illustrates how ecophysiological differences can shift the competitive advantage from one species to another along a stress gradient. Phragmites australis is spreading into North American coastal marshes that are experiencing reduced salinities, while Spartina spp. are spreading into northern European brackish marshes that are experiencing increased salinities as land use patterns change on the two continents.

  8. Natural protein engineering: a uniquely salt-tolerant, but not halophilic, alpha-type carbonic anhydrase from algae proliferating in low- to hyper-saline environments.

    PubMed

    Bageshwar, Umesh K; Premkumar, Lakshmanane; Gokhman, Irena; Savchenko, Tatyana; Sussman, Joel L; Zamir, Ada

    2004-02-01

    Dunaliella salina is a unicellular green alga thriving in environments ranging from fresh water to hyper-saline lakes, such as the Dead Sea. An unusual, internally duplicated, 60 kDa alpha-type carbonic anhydrase (dCA I), located on the surface of this alga, is expected to function over a broad range of salinities. It would therefore differ from other carbonic anhydrases that already lose activity at low salinities and also from halophilic proteins that require high salinities for conformational stability. Enzymatic analyses indeed indicated that dCA I retained activity at salt concentrations ranging from low salt to at least 1.5 M NaCl or KCl for CO(2) hydration, 2.0 M NaCl for esterase activity and 0.5 M for bicarbonate dehydration. Although measurements at higher salinities were constrained by the interference of salt in the respective assayed reactions, activity was noticeable even at 4.0 M NaCl. Comparisons of the internally duplicated dCA I to single-domain derivatives indicated that inter-domain interactions played a decisive role in the stability, activity, salt tolerance and pH responses of dCA I. Hence dCA I is a uniquely salt- tolerant protein, retaining an active conformation over a large range of salinities and, as a Zn metalloenzyme, largely immune to the specific inhibitory effects of anions. Its unique features make dCA I a useful model to understand the physico-chemical basis of halotolerance and protein-salt interactions in general. PMID:15047915

  9. The Effect of Exogenous Spermidine Concentration on Polyamine Metabolism and Salt Tolerance in Zoysiagrass (Zoysia japonica Steud) Subjected to Short-Term Salinity Stress

    PubMed Central

    Li, Shucheng; Jin, Han; Zhang, Qiang

    2016-01-01

    Salt stress, particularly short-term salt stress, is among the most serious abiotic factors limiting plant survival and growth in China. It has been established that exogenous spermidine (Spd) stimulates plant tolerance to salt stress. The present study utilized two zoysiagrass cultivars commonly grown in China that exhibit either sensitive (cv. Z081) or tolerant (cv. Z057) adaptation capacity to salt stress. The two cultivars were subjected to 200 mM salt stress and treated with different exogenous Spd concentrations for 8 days. Polyamine [diamine putrescine (Put), tetraamine spermine (Spm), and Spd], H2O2 and malondialdehyde (MDA) contents and polyamine metabolic (ADC, ODC, SAMDC, PAO, and DAO) and antioxidant (superoxide dismutase, catalase, and peroxidase) enzyme activities were measured. The results showed that salt stress induced increases in Spd and Spm contents and ornithine decarboxylase (ODC), S-adenosylmethionine decarboxylase (SAMDC), and diamine oxidase (DAO) activities in both cultivars. Exogenous Spd application did not alter polyamine contents via regulation of polyamine-degrading enzymes, and an increase in polyamine biosynthetic enzyme levels was observed during the experiment. Increasing the concentration of exogenous Spd resulted in a tendency of the Spd and Spm contents and ODC, SAMDC, DAO, and antioxidant enzyme activities to first increase and then decrease in both cultivars. H2O2 and MDA levels significantly decreased in both cultivars treated with Spd. Additionally, in both cultivars, positive correlations between polyamine biosynthetic enzymes (ADC, SAMDC), DAO, and antioxidant enzymes (SOD, POD, CAT), but negative correlations with H2O2 and MDA levels, and the Spd + Spm content were observed with an increase in the concentration of exogenous Spd. PMID:27582752

  10. The Effect of Exogenous Spermidine Concentration on Polyamine Metabolism and Salt Tolerance in Zoysiagrass (Zoysia japonica Steud) Subjected to Short-Term Salinity Stress.

    PubMed

    Li, Shucheng; Jin, Han; Zhang, Qiang

    2016-01-01

    Salt stress, particularly short-term salt stress, is among the most serious abiotic factors limiting plant survival and growth in China. It has been established that exogenous spermidine (Spd) stimulates plant tolerance to salt stress. The present study utilized two zoysiagrass cultivars commonly grown in China that exhibit either sensitive (cv. Z081) or tolerant (cv. Z057) adaptation capacity to salt stress. The two cultivars were subjected to 200 mM salt stress and treated with different exogenous Spd concentrations for 8 days. Polyamine [diamine putrescine (Put), tetraamine spermine (Spm), and Spd], H2O2 and malondialdehyde (MDA) contents and polyamine metabolic (ADC, ODC, SAMDC, PAO, and DAO) and antioxidant (superoxide dismutase, catalase, and peroxidase) enzyme activities were measured. The results showed that salt stress induced increases in Spd and Spm contents and ornithine decarboxylase (ODC), S-adenosylmethionine decarboxylase (SAMDC), and diamine oxidase (DAO) activities in both cultivars. Exogenous Spd application did not alter polyamine contents via regulation of polyamine-degrading enzymes, and an increase in polyamine biosynthetic enzyme levels was observed during the experiment. Increasing the concentration of exogenous Spd resulted in a tendency of the Spd and Spm contents and ODC, SAMDC, DAO, and antioxidant enzyme activities to first increase and then decrease in both cultivars. H2O2 and MDA levels significantly decreased in both cultivars treated with Spd. Additionally, in both cultivars, positive correlations between polyamine biosynthetic enzymes (ADC, SAMDC), DAO, and antioxidant enzymes (SOD, POD, CAT), but negative correlations with H2O2 and MDA levels, and the Spd + Spm content were observed with an increase in the concentration of exogenous Spd. PMID:27582752

  11. Maintenance of Chloroplast Structure and Function by Overexpression of the Rice MONOGALACTOSYLDIACYLGLYCEROL SYNTHASE Gene Leads to Enhanced Salt Tolerance in Tobacco1[W

    PubMed Central

    Wang, Shiwen; Uddin, M. Imtiaz; Tanaka, Kiyoshi; Yin, Lina; Shi, Zhonghui; Qi, Yanhua; Mano, Jun’ichi; Matsui, Kenji; Shimomura, Norihiro; Sakaki, Takeshi; Deng, Xiping; Zhang, Suiqi

    2014-01-01

    In plants, the galactolipids monogalactosyldiacylglycerol (MGDG) and digalactodiacylglycerol (DGDG) are major constituents of photosynthetic membranes in chloroplasts. One of the key enzymes for the biosynthesis of these galactolipids is MGDG synthase (MGD). To investigate the role of MGD in the plant’s response to salt stress, we cloned an MGD gene from rice (Oryza sativa) and generated tobacco (Nicotiana tabacum) plants overexpressing OsMGD. The MGD activity in OsMGD transgenic plants was confirmed to be higher than that in the wild-type tobacco cultivar SR1. Immunoblot analysis indicated that OsMGD was enriched in the outer envelope membrane of the tobacco chloroplast. Under salt stress, the transgenic plants exhibited rapid shoot growth and high photosynthetic rate as compared with the wild type. Transmission electron microscopy observation showed that the chloroplasts from salt-stressed transgenic plants had well-developed thylakoid membranes and properly stacked grana lamellae, whereas the chloroplasts from salt-stressed wild-type plants were fairly disorganized and had large membrane-free areas. Under salt stress, the transgenic plants also maintained higher chlorophyll levels. Lipid composition analysis showed that leaves of transgenic plants consistently contained significantly higher MGDG (including 18:3-16:3 and 18:3-18:3 species) and DGDG (including 18:3-16:3, 18:3-16:0, and 18:3-18:3 species) contents and higher DGDG-MGDG ratios than the wild type did under both control and salt stress conditions. These results show that overexpression of OsMGD improves salt tolerance in tobacco and that the galactolipids MGDG and DGDG play an important role in the regulation of chloroplast structure and function in the plant salt stress response. PMID:24843077

  12. Isolation of a salt tolerant laccase secreting strain of Trichoderma sp. NFCCI-2745 and optimization of culture conditions and assessing its effectiveness in treating saline phenolic effluents.

    PubMed

    Divya, L M; Prasanth, G K; Sadasivan, C

    2013-12-01

    Most of the hazardous pollutants are phenolic in nature and persists in the environment. The ability of laccases to oxidize phenolic compounds and reduce molecular oxygen to water has led to intensive studies of these enzymes. Therefore the fungal strains with high laccase activity and substrate affinity that can tolerate harsh environmental conditions have a potential for biotechnological applications. Salt tolerant laccase secreting fungi can be utilized in treatment of saline and phenolic rich industrial effluents such as coir effluent and textile effluent that needed to be diluted several fold before microbial treatment. This is the first study describing the isolation and optimization of a salt tolerant strain of Trichoderma sp. potential for industrial applications. The fungus was identified based on morphological characteristics and was subsequently confirmed with molecular techniques and deposited at National Fungal Culture Collections of India (NFCCI) under the Accession No. Trichoderma viride NFCCI 2745. In contrast to other laccase secreting fungi, light conditions did not exert much influence on laccase production of this strain and salinity enhanced its laccase secretion. The fungus effectively removed the phenolic content of the textile effluent, coir-ret liquor and wood processing effluent within 96 hr of incubation. The tolerance of the fungus to high salinity and phenolic compounds makes this strain ideal for treating saline and phenolic rich industrial effluents. PMID:24649671

  13. Experimental Microbiology of Saturated Salt Solutions and Other Harsh Environments. III. Growth of Salt-Tolerant Penicillium notatum in Boron-Rich Media 1

    PubMed Central

    Roberts, Karen; Siegel, S. M.

    1967-01-01

    A stress-tolerant strain of Penicillium notatum, isolated by passage through a nutrient solution saturated with calcium acetate, was found to have a tolerance to boron in several states of oxidation. Growth in the presence of elementary boron, saturating amounts of boric acid, and with various concentrations of sodium borohydride was observed and mycelial mats were spectrographically analyzed for boron accumulation. PMID:6076112

  14. An ER-targeted calcium-binding peptide confers salt and drought tolerance mediated by CIPK6 in Arabidopsis.

    PubMed

    Tsou, Pei-Lan; Lee, Sang Yoon; Allen, Nina Stromgren; Winter-Sederoff, Heike; Robertson, Dominique

    2012-03-01

    Different plant organelles have high internal stores of Ca(2+) compared to the cytoplasm and could play independent roles in stress responses or signal transduction. We used a GFP fusion with the C-domain of calreticulin, which shows low-affinity, high capacity Ca(2+) binding in the ER, as a calcium-binding peptide (CBP) to specifically increase stores in the ER and nucleus. Despite the presence of a signal sequence and KDEL retention sequence, our work and previous studies (Brandizzi et al. Plant Journal 34:269-281, 2003) demonstrated both ER and nuclear localization of GFP-CBP. Under normal conditions, GFP-CBP-expressing lines had ~25% more total Ca(2+) and higher levels of chlorophyll and seed yield than wild type and GFP controls. CBP-expressing plants also had better survival under intermittent drought or high salt treatments and increased root growth. One member of the CIPK (calcineurin B-like interacting protein kinase) gene family, CIPK6, was up-regulated in CBP-expressing plants, even under non-stress conditions. A null mutation in cipk6 abolished the increased stress tolerance of CBP-transgenic plants, as well as the CBP-mediated induction of two stress-associated genes, DREB1A and RD29A, under non-stress conditions. Although this suggested that it was the induction of CIPK6, rather than localized changes in Ca(2+), that resulted in increased survival under adverse conditions, CIPK6 induction still required Ca(2+). This work demonstrates that ER (or nuclear) Ca(2+) can directly participate in signal transduction to alter gene expression. The discovery of a method for increasing Ca(2+) levels without deleterious effects on plant growth may have practical applications. PMID:21971994

  15. The modulation of leaf metabolism plays a role in salt tolerance of Cymodocea nodosa exposed to hypersaline stress in mesocosms

    PubMed Central

    Piro, Amalia; Marín-Guirao, Lázaro; Serra, Ilia A.; Spadafora, Antonia; Sandoval-Gil, José M.; Bernardeau-Esteller, Jaime; Fernandez, Juan M. R.; Mazzuca, Silvia

    2015-01-01

    Applying proteomics, we tested the physiological responses of the euryhaline seagrass Cymodocea nodosa to deliberate manipulation of salinity in a mesocosm system. Plants were subjected to a chronic hypersaline condition (43 psu) to compare protein expression and plant photochemistry responses after 15 and 30 days of exposure with those of plants cultured under normal/ambient saline conditions (37 psu). Results showed a general decline in the expression level of leaf proteins in hypersaline stressed plants, with more intense reductions after long-lasting exposure. Specifically, the carbon-fixing enzyme RuBisCo displayed a lower accumulation level in stressed plants relative to controls. In contrast, the key enzymes involved in the regulation of glycolysis, cytosolic glyceraldehyde-3-phosphate dehydrogenase, enolase 2 and triose-phosphate isomerase, showed significantly higher accumulation levels. These responses suggested a shift in carbon metabolism in stressed plants. Hypersaline stress also induced a significant alteration of the photosynthetic physiology of C. nodosa by means of a down-regulation in structural proteins and enzymes of both PSII and PSI. However we found an over-expression of the cytochrome b559 alpha subunit of the PSII initial complex, which is a receptor for the PSII core proteins involved in biogenesis or repair processes and therefore potentially involved in the absence of effects at the photochemical level of stressed plants. As expected hypersalinity also affects vacuolar metabolism by increasing the leaf cell turgor pressure and enhancing the up-take of Na+ by over-accumulating the tonoplast specific intrinsic protein pyrophosphate-energized inorganic pyrophosphatase (H(+)-PPase) coupled to the Na+/H+-antiporter. The modulation of carbon metabolism and the enhancement of vacuole capacity in Na+ sequestration and osmolarity changes are discussed in relation to salt tolerance of C. nodosa. PMID:26167167

  16. Feasibility study of semi-selective protein precipitation with salt-tolerant copolymers for industrial purification of therapeutic antibodies.

    PubMed

    Capito, Florian; Bauer, Johann; Rapp, Almut; Schröter, Christian; Kolmar, Harald; Stanislawski, Bernd

    2013-11-01

    We present a feasibility study for an antibody capturing process from clarified cell culture fluid using semi-selective protein precipitation with salt-tolerant copolymers. Protein precipitation is mediated by hydrophobic and electrostatic interactions with the copolymer that can be customized for the respective target. Precipitation yield with different copolymers at ionic strength of 2-22.5 mS cm⁻¹ and pH 5.0-pH 5.7 was evaluated using pure monoclonal antibody solutions. Optimized parameters were used to elucidate yield and purity of various antibodies precipitated at physiological conditions from cell culture fluid of CHO, NS0, and SP2/0 cell culture fluid. Precipitated protein was easily redissolved in small volume, enabling concentrating monoclonal antibodies (mAb) more than 40-fold and up to 100-fold, while residual polymer was removed to >98% using cationic polymer attached to silica flakes. mAb recovery of >90% and host cell protein clearance of >80% were achieved, not requiring any pre-dilution of cell culture fluid. Precipitation showed no impact on mAb binding affinity when compared to non-precipitated mAb. The obtained yield and purity were lower compared to a protein A based purification and loss of mAb was factor 1.5-3.0 higher. Yet, for high titer mAb purification processes being implemented in the future, precipitation is an attractive option due to its ease of scalability and cost-effectiveness. PMID:23637026

  17. Purification and photobiochemical profile of photosystem 1 from a high-salt tolerant, oleaginous Chlorella (Trebouxiophycaea, Chlorophyta).

    PubMed

    McConnell, Michael D; Lowry, David; Rowan, Troy N; van Dijk, Karin; Redding, Kevin E

    2015-06-01

    The eukaryotic green alga Chlamydomonas reinhardtii has been studied extensively within the biofuel industry as a model organism, as researchers look towards algae to provide chemical feedstocks (i.e., lipids) for the production of liquid transportation fuels. C. reinhardtii, however, is unsuitable for high-level production of such precursors due to its relatively poor lipid accumulation and fresh-water demand. In this study we offer insight into the primary light harvesting and electron transfer reactions that occur during phototropic growth in a high-salt tolerant strain of Chlorella (a novel strain introduced here as NE1401), a single-celled eukaryotic algae also in the phylum Chlorophyta. Under nutrient starvation many eukaryotic algae increase dramatically the amount of lipids stored in lipid bodies within their cell interiors. Microscopy and lipid analyses indicate that Chlorella sp. NE1401 may become a superior candidate for algal biofuels production. We have purified highly active Photosystem 1 (PS1) complexes to study in vitro, so that we may understand further the photobiochemisty of this promising biofuel producer and how its characteristics compare and contrast with that of the better understood C. reinhardtii. Our findings suggest that the PS1 complex from Chlorella sp. NE1401 demonstrates similar characteristics to that of C. reinhardtii with respect to light-harvesting and electron transfer reactions. We also illustrate that the relative extent of the light state transition performed by Chlorella sp. NE1401 is smaller compared to C. reinhardtii, although they are triggered by the same dynamic light stresses. PMID:25600216

  18. AtPP2CG1, a protein phosphatase 2C, positively regulates salt tolerance of Arabidopsis in abscisic acid-dependent manner

    SciTech Connect

    Liu, Xin; Zhu, Yanming; Zhai, Hong; Cai, Hua; Ji, Wei; Luo, Xiao; Li, Jing; Bai, Xi

    2012-06-15

    Highlights: Black-Right-Pointing-Pointer AtPP2CG1 positively regulates salt tolerance in ABA-dependent manner. Black-Right-Pointing-Pointer AtPP2CG1 up-regulates the expression of marker genes in different pathways. Black-Right-Pointing-Pointer AtPP2CG1 expresses in the vascular system and trichomes of Arabidopsis. -- Abstract: AtPP2CG1 (Arabidopsis thaliana protein phosphatase 2C G Group 1) was predicted as an abiotic stress candidate gene by bioinformatic analysis in our previous study. The gene encodes a putative protein phosphatase 2C that belongs to Group G of PP2C. There is no report of Group G genes involved in abiotic stress so far. Real-time RT-PCR analysis showed that AtPP2CG1 expression was induced by salt, drought, and abscisic acid (ABA) treatment. The expression levels of AtPP2CG1 in the ABA synthesis-deficient mutant abi2-3 were much lower than that in WT plants under salt stress suggesting that the expression of AtPP2CG1 acts in an ABA-dependent manner. Over-expression of AtPP2CG1 led to enhanced salt tolerance, whereas its loss of function caused decreased salt tolerance. These results indicate that AtPP2CG1 positively regulates salt stress in an ABA-dependent manner. Under salt treatment, AtPP2CG1 up-regulated the expression levels of stress-responsive genes, including RD29A, RD29B, DREB2A and KIN1. GUS activity was detected in roots, leaves, stems, flower, and trichomes of AtPP2CG1 promoter-GUS transgenic plants. AtPP2CG1 protein was localized in nucleus and cytoplasm via AtPP2CG1:eGFP and YFP:AtPP2CG1 fusion approaches.

  19. Inverse modulation of the energy sensor Snf1-related protein kinase 1 on hypoxia adaptation and salt stress tolerance in Arabidopsis thaliana.

    PubMed

    Im, Jong Hee; Cho, Young-Hee; Kim, Geun-Don; Kang, Geun-Ho; Hong, Jung-Woo; Yoo, Sang-Dong

    2014-10-01

    Terrestrial plants are exposed to complex stresses of high salt-induced abscisic acid (ABA) and submergence-induced hypoxia when seawater floods fields. Many studies have investigated plant responses to individual stress conditions, but not so much for coupled or sequentially imposed stresses. We examined molecular regulatory mechanisms of gene expression underlying the cellular responses involved in crosstalk between salt and hypoxia stresses. Salt/ABA- and AtMYC2-dependent induction of a synthetic ABA-responsive element and the native RD22 promoters were utilized in our cell-based functional assays. Such promoter-based reporter induction was largely inhibited by hypoxia and hypoxia-inducible AKIN10 activity. Biochemical analyses showed that AKIN10 negatively modulates AtMYC2 protein accumulation via proteasome activity upon AKIN10 kinase activity-dependent protein modification. Further genetic analysis using transgenic plants expressing AKIN10 provided evidence that AKIN10 activity undermined AtMYC2-dependent salt tolerance. Our findings unravel a novel molecular interaction between the key signalling constituents leading crosstalk between salt and hypoxia stresses in Arabidopsis thaliana under the detrimental condition of submergence in saltwater. PMID:24890857

  20. Overexpression of soybean R2R3-MYB transcription factor, GmMYB12B2, and tolerance to UV radiation and salt stress in transgenic Arabidopsis.

    PubMed

    Li, X W; Wang, Y; Yan, F; Li, J W; Zhao, Y; Zhao, X; Zhai, Y; Wang, Q Y

    2016-01-01

    MYB, v-myb avian myeloblastosis viral oncogene homolog, proteins play central roles in plant stress response. Previously, we identified a novel R2R3-MYB transcription factor, GmMYB12B2, which affected the expression levels of some key enzyme genes involved in flavonoid biosynthesis in transgenic Arabidopsis. In the present study, we analyzed the expression levels of GmMYB12B2 under salt, low temperature, drought, abscisic acid (ABA), and ultraviolet (UV) radiation treatments in soybean using semi-quantitative reverse transcription polymerase chain reaction. The expression of GmMYB12B2 was drastically induced by UV irradiation and salt treatment, but no response was detected under low temperature, drought, and ABA stresses. A detailed characterization of the GmMYB12B2 overexpression lines revealed that GmMYB12B2 might be involved in response of plants to UV radiation and salt stresses. Transgenic Arabidopsis lines constitutively expressing GmMYB12B2 showed an increased tolerance to salt and UV radiation treatment compared with wild-type plants. The expression levels of certain salt stress-responsive genes, such as DREB2A and RD17, were found to be elevated in the transgenic plants. These results indicate that GmMYB12B2 acts as a regulator in the plant stress response. PMID:27323089

  1. Enhancement of DNaseI Salt Tolerance by Mimicking the Domain Structure of DNase from an Extremely Halotolerant Bacterium Thioalkalivibrio sp. K90mix

    PubMed Central

    Alzbutas, Gediminas; Kaniusaite, Milda; Lagunavicius, Arunas

    2016-01-01

    In our previous work we showed that DNaseI-like protein from an extremely halotolerant bacterium Thioalkalivibrio sp. K90mix retained its activity at salt concentrations as high as 4 M NaCl and the key factor allowing this was the C-terminal DNA-binding domain, which comprised two HhH (helix-hairpin-helix) motifs. The further investigations revealed that this domain originated from proteins related to bacterial competence ComEA/ComE proteins. It is likely that in the course of evolution the DNA-binding domain from these proteins was fused to a metallo-β-lactamase superfamily domain. Very likely such domain organization having proteins subsequently “donated” the DNA-binding domain to bacterial DNases. In this study we have mimicked this evolutionary step by fusing bovine DNaseI and DNA-binding domains. We have created two fusions: one harboring the DNA-binding domain of DNaseI-like protein from Thioalkalivibrio sp. K90mix and the second one harboring the DNA-binding domain of bacterial competence protein ComEA from Bacillus subtilis. Both domains enhanced salt tolerance of DNaseI, albeit to different extent. Molecular modeling revealed the essential differences between their interaction with DNA shedding some light on the differences in salt tolerance. In this study we have enhanced salt tolerance of bovine DNaseI; thus, we successfully mimicked the Nature’s evolutionary engineering that created the extremely halotolerant bacterial DNase. We have demonstrated that the newly engineered DNaseI variants can be successfully used in applications where activity of the wild type bovine DNaseI is impeded by buffers used. PMID:26939122

  2. Enhancement of DNaseI Salt Tolerance by Mimicking the Domain Structure of DNase from an Extremely Halotolerant Bacterium Thioalkalivibrio sp. K90mix.

    PubMed

    Alzbutas, Gediminas; Kaniusaite, Milda; Lagunavicius, Arunas

    2016-01-01

    In our previous work we showed that DNaseI-like protein from an extremely halotolerant bacterium Thioalkalivibrio sp. K90mix retained its activity at salt concentrations as high as 4 M NaCl and the key factor allowing this was the C-terminal DNA-binding domain, which comprised two HhH (helix-hairpin-helix) motifs. The further investigations revealed that this domain originated from proteins related to bacterial competence ComEA/ComE proteins. It is likely that in the course of evolution the DNA-binding domain from these proteins was fused to a metallo-β-lactamase superfamily domain. Very likely such domain organization having proteins subsequently "donated" the DNA-binding domain to bacterial DNases. In this study we have mimicked this evolutionary step by fusing bovine DNaseI and DNA-binding domains. We have created two fusions: one harboring the DNA-binding domain of DNaseI-like protein from Thioalkalivibrio sp. K90mix and the second one harboring the DNA-binding domain of bacterial competence protein ComEA from Bacillus subtilis. Both domains enhanced salt tolerance of DNaseI, albeit to different extent. Molecular modeling revealed the essential differences between their interaction with DNA shedding some light on the differences in salt tolerance. In this study we have enhanced salt tolerance of bovine DNaseI; thus, we successfully mimicked the Nature's evolutionary engineering that created the extremely halotolerant bacterial DNase. We have demonstrated that the newly engineered DNaseI variants can be successfully used in applications where activity of the wild type bovine DNaseI is impeded by buffers used. PMID:26939122

  3. Difference in root K+ retention ability and reduced sensitivity of K+-permeable channels to reactive oxygen species confer differential salt tolerance in three Brassica species

    PubMed Central

    Chakraborty, Koushik; Bose, Jayakumar; Shabala, Lana; Shabala, Sergey

    2016-01-01

    Brassica species are known to possess significant inter and intraspecies variability in salinity stress tolerance, but the cell-specific mechanisms conferring this difference remain elusive. In this work, the role and relative contribution of several key plasma membrane transporters to salinity stress tolerance were evaluated in three Brassica species (B. napus, B. juncea, and B. oleracea) using a range of electrophysiological assays. Initial root growth assay and viability staining revealed that B. napus was most tolerant amongst the three species, followed by B. juncea and B. oleracea. At the mechanistic level, this difference was conferred by at least three complementary physiological mechanisms: (i) higher Na+ extrusion ability from roots resulting from increased expression and activity of plasma membrane SOS1-like Na+/H+ exchangers; (ii) better root K+ retention ability resulting from stress-inducible activation of H+-ATPase and ability to maintain more negative membrane potential under saline conditions; and (iii) reduced sensitivity of B. napus root K+-permeable channels to reactive oxygen species (ROS). The last two mechanisms played the dominant role and conferred most of the differential salt sensitivity between species. Brassica napus plants were also more efficient in preventing the stress-induced increase in GORK transcript levels and up-regulation of expression of AKT1, HAK5, and HKT1 transporter genes. Taken together, our data provide the mechanistic explanation for differential salt stress sensitivity amongst these species and shed light on transcriptional and post-translational regulation of key ion transport systems involved in the maintenance of the root plasma membrane potential and cytosolic K/Na ratio as a key attribute for salt tolerance in Brassica species. PMID:27340231

  4. Transgenic rice expressing a cassava (Manihot esculenta Crantz) plasma membrane gene MePMP3-2 exhibits enhanced tolerance to salt and drought stresses.

    PubMed

    Yu, Y; Cui, Y C; Ren, C; Rocha, P S C F; Peng, M; Xu, G Y; Wang, M L; Xia, X J

    2016-01-01

    Plasma membrane proteolipid 3 (PMP3) is a class of small hydrophobic proteins found in many organisms including higher plants. Some plant PMP3 genes have been shown to respond to abiotic stresses and to participate in the processes of plant stress tolerance. In this study, we isolated the cassava (Manihot esculenta Crantz) MePMP3-2 gene and functionally characterized its role in tolerance to abiotic stress by expressing it in rice (Oryza sativa L.). MePMP3-2 encodes a 77-amino acid protein belonging to a subgroup of plant PMP3s that have long hydrophylic C-terminal tails of unknown function. In silico analysis and co-localization studies indicated that MePMP3-2 is a plasma membrane protein with two transmembrane domains, similar to other PMP3s. In cassava leaves, MePMP3-2 expression was up-regulated by salt and drought stresses. Heterologous constitutive expression of MePMP3-2 in rice did not alter plant growth and development but increased tolerance to salt and drought stresses. In addition, under stress conditions MePMP3-2 transgenic plants accumulated less malondialdehyde, had increased levels of proline, and exhibited greater up-regulation of the stress-related genes OsProT and OsP5CS, but led to only minor changes in OsDREB2A and OsLEA3 expression. These findings indicate that MePMP3-2 may play an important role in salt and drought stress tolerance in transgenic rice. PMID:26909954

  5. Difference in root K+ retention ability and reduced sensitivity of K+-permeable channels to reactive oxygen species confer differential salt tolerance in three Brassica species.

    PubMed

    Chakraborty, Koushik; Bose, Jayakumar; Shabala, Lana; Shabala, Sergey

    2016-08-01

    Brassica species are known to possess significant inter and intraspecies variability in salinity stress tolerance, but the cell-specific mechanisms conferring this difference remain elusive. In this work, the role and relative contribution of several key plasma membrane transporters to salinity stress tolerance were evaluated in three Brassica species (B. napus, B. juncea, and B. oleracea) using a range of electrophysiological assays. Initial root growth assay and viability staining revealed that B. napus was most tolerant amongst the three species, followed by B. juncea and B. oleracea At the mechanistic level, this difference was conferred by at least three complementary physiological mechanisms: (i) higher Na(+) extrusion ability from roots resulting from increased expression and activity of plasma membrane SOS1-like Na(+)/H(+) exchangers; (ii) better root K(+) retention ability resulting from stress-inducible activation of H(+)-ATPase and ability to maintain more negative membrane potential under saline conditions; and (iii) reduced sensitivity of B. napus root K(+)-permeable channels to reactive oxygen species (ROS). The last two mechanisms played the dominant role and conferred most of the differential salt sensitivity between species. Brassica napus plants were also more efficient in preventing the stress-induced increase in GORK transcript levels and up-regulation of expression of AKT1, HAK5, and HKT1 transporter genes. Taken together, our data provide the mechanistic explanation for differential salt stress sensitivity amongst these species and shed light on transcriptional and post-translational regulation of key ion transport systems involved in the maintenance of the root plasma membrane potential and cytosolic K/Na ratio as a key attribute for salt tolerance in Brassica species. PMID:27340231

  6. Proteomic identification of OsCYP2, a rice cyclophilin that confers salt tolerance in rice (Oryza sativa L.) seedlings when overexpressed

    PubMed Central

    2011-01-01

    Background High Salinity is a major environmental stress influencing growth and development of rice. Comparative proteomic analysis of hybrid rice shoot proteins from Shanyou 10 seedlings, a salt-tolerant hybrid variety, and Liangyoupeijiu seedlings, a salt-sensitive hybrid variety, was performed to identify new components involved in salt-stress signaling. Results Phenotypic analysis of one protein that was upregulated during salt-induced stress, cyclophilin 2 (OsCYP2), indicated that OsCYP2 transgenic rice seedlings had better tolerance to salt stress than did wild-type seedlings. Interestingly, wild-type seedlings exhibited a marked reduction in maximal photochemical efficiency under salt stress, whereas no such change was observed for OsCYP2-transgenic seedlings. OsCYP2-transgenic seedlings had lower levels of lipid peroxidation products and higher activities of antioxidant enzymes than wild-type seedlings. Spatiotemporal expression analysis of OsCYP2 showed that it could be induced by salt stress in both Shanyou 10 and Liangyoupeijiu seedlings, but Shanyou 10 seedlings showed higher OsCYP2 expression levels. Moreover, circadian rhythm expression of OsCYP2 in Shanyou 10 seedlings occurred earlier than in Liangyoupeijiu seedlings. Treatment with PEG, heat, or ABA induced OsCYP2 expression in Shanyou 10 seedlings but inhibited its expression in Liangyoupeijiu seedlings. Cold stress inhibited OsCYP2 expression in Shanyou 10 and Liangyoupeijiu seedlings. In addition, OsCYP2 was strongly expressed in shoots but rarely in roots in two rice hybrid varieties. Conclusions Together, these data suggest that OsCYP2 may act as a key regulator that controls ROS level by modulating activities of antioxidant enzymes at translation level. OsCYP2 expression is not only induced by salt stress, but also regulated by circadian rhythm. Moreover, OsCYP2 is also likely to act as a key component that is involved in signal pathways of other types of stresses-PEG, heat, cold, or ABA

  7. Cloning and Functional Characterization of a Vacuolar Na+/H+ Antiporter Gene from Mungbean (VrNHX1) and Its Ectopic Expression Enhanced Salt Tolerance in Arabidopsis thaliana

    PubMed Central

    Mishra, Sagarika; Alavilli, Hemasundar; Lee, Byeong-ha; Panda, Sanjib Kumar; Sahoo, Lingaraj

    2014-01-01

    Plant vacuolar NHX exchangers play a significant role in adaption to salt stress by compartmentalizing excess cytosolic Na+ into vacuoles and maintaining cellular homeostasis and ionic equilibrium. We cloned an orthologue of the vacuolar Na+/H+ antiporter gene, VrNHX1 from mungbean (Vigna radiata), an important Asiatic grain legume. The VrNHX1 (Genbank Accession number JN656211.1) contains 2095 nucleotides with an open reading frame of 1629 nucleotides encoding a predicted protein of 542 amino acids with a deduced molecular mass of 59.6 kDa. The consensus amiloride binding motif (84LFFIYLLPPI93) was observed in the third putative transmembrane domain of VrNHX1. Bioinformatic and phylogenetic analysis clearly suggested that VrNHX1 had high similarity to those of orthologs belonging to Class-I clade of plant NHX exchangers in leguminous crops. VrNHX1 could be strongly induced by salt stress in mungbean as the expression in roots significantly increased in presence of 200 mM NaCl with concomitant accumulation of total [Na+]. Induction of VrNHX1 was also observed under cold and dehydration stress, indicating a possible cross talk between various abiotic stresses. Heterologous expression in salt sensitive yeast mutant AXT3 complemented for the loss of yeast vacuolar NHX1 under NaCl, KCl and LiCl stress indicating that VrNHX1 was the orthologue of ScNHX1. Further, AXT3 cells expressing VrNHX1 survived under low pH environment and displayed vacuolar alkalinization analyzed using pH sensitive fluorescent dye BCECF-AM. The constitutive and stress inducible expression of VrNHX1 resulted in enhanced salt tolerance in transgenic Arabidopsis thaliana lines. Our work suggested that VrNHX1 was a salt tolerance determinant in mungbean. PMID:25350285

  8. 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...

  9. Optimization studies on production of a salt-tolerant protease from Pseudomonas aeruginosa strain BC1 and its application on tannery saline wastewater treatment

    PubMed Central

    Sivaprakasam, Senthilkumar; Dhandapani, Balaji; Mahadevan, Surianarayanan

    2011-01-01

    Treatment and safe disposal of tannery saline wastewater, a primary effluent stream that is generated by soaking salt-laden hides and skin is one of the major problems faced by the leather manufacturing industries. Conventional treatment methods like solar evaporation ponds and land composting are not eco-friendly as they deteriorate the ground water quality. Though, this waste stream is comprised of high concentration of dissolved proteins the presence of high salinity (1–6 % NaCl by wt) makes it non-biodegradable. Enzymatic treatment is one of the positive alternatives for management of such kind of waste streams. A novel salt-tolerant alkaline protease obtained from P.aeruginosa (isolated from tannery saline wastewater) was used for enzymatic degradation studies. The effect of various physical factors including pH, temperature, incubation time, protein source and salinity on the activity of identified protease were investigated. Kinetic parameters (Km , Vmax) were calculated for the identified alkaline protease at varying substrate concentrations. Tannery saline wastewater treated with identified salt tolerant protease showed 75 % protein removal at 6 h duration and 2 % (v/v) protease addition was found to be the optimum dosage value. PMID:24031785

  10. Improved catalytic efficiency, thermophilicity, anti-salt and detergent tolerance of keratinase KerSMD by partially truncation of PPC domain

    PubMed Central

    Fang, Zhen; Zhang, Juan; Du, Guocheng; Chen, Jian

    2016-01-01

    The keratinase from Stenotrophomonas maltophilia (KerSMD) is known for its high activity and pH stability in keratin degradation. However, catalytic efficiency and detergent tolerability need to be improved in order to be used for industrial application. In this work, we obtained several keratinase variants with enhanced catalytic efficiency, thermophilicity, and anti-salt and detergent tolerability by partially truncating the PPC domain of KerSMD. The variants all showed improved catalytic efficiency to synthetic substrate AAPF, with the V355 variant having the highest kcat /Km value of 143.6 s−1 mM−1. The truncation of keratinase had little effect on alkaline stability but obviously decreased collagenase activity, developing its potential application in leather treatment. The variants V380, V370, and V355 were thermophilic, with a 1.7-fold enhancement of keratinlytic activity at 60 °C when compared to the wild type. The entire truncation of PPC domain obtained the variant V355 with improved tolerance to alkalinity, salt, chaotropic agents, and detergents. The V355 variant showed more than a 40% improvement in activity under 15% (w/v) NaCl or 4% (w/v) SDS solution, showing excellent stability under harsh washing and unhairing conditions. Our work investigated how protein engineering affects the function of PPC domain of KerSMD. PMID:27298079

  11. A novel tomato MYC-type ICE1-like transcription factor, SlICE1a, confers cold, osmotic and salt tolerance in transgenic tobacco.

    PubMed

    Feng, Hai-Long; Ma, Na-Na; Meng, Xia; Zhang, Song; Wang, Jie-Ru; Chai, Sen; Meng, Qing-Wei

    2013-12-01

    ICE1 (inducer of CBF expression 1), a MYC-type bHLH transcription factor, is an important activator of CBF3/DREB1A for regulating cold signaling and stress tolerance. In this study, we isolated the novel ICE1-like gene SlICE1a from tomato which contains the conserved bHLH domain, an S-rich motif, and ACT-domain. It is localized in the nucleus and harbors transcription-activating activity in the N-terminal. In addition, the SlICE1a transcript is slightly upregulated by cold stress, salt stress, and osmotic stress. SlICE1a overexpression in tobacco enhances the induction of CBF/DREB and their target genes, consequently increasing the levels of proline, soluble sugars, and late embryogenesis abundant (LEA) proteins, and enhancing tolerance to cold stress, osmotic stress, and salt stress. SlICE1a functions in abiotic stress responses by regulating the expression of stress-tolerant genes, and is thus beneficial for crop improvement. PMID:24184451

  12. Potential of the salt-tolerant laccase-producing strain Trichoderma viride Pers. NFCCI-2745 from an estuary in the bioremediation of phenol-polluted environments.

    PubMed

    Divya, L M; Prasanth, G K; Sadasivan, C

    2014-06-01

    Industrialization causes the generation of phenolic pollutants in the environment. The ability of laccases to oxidize phenolic compounds and reduce molecular oxygen to water has led to intensive studies on these enzymes. Although salt-tolerant fungi are potential sources of enzymes for industrial applications, they have been inadequately explored for laccase production. This study describes the isolation of a salt- and phenol-tolerant strain of Trichoderma sp. with the ability to produce laccase, and thus with the potential for industrial applications. The coconut husk retting ground in the estuaries of Kerala, India, a saline environment highly polluted with phenolic compounds, was selected for isolating the fungus. Enhanced laccase production was observed at 5-10 ppt salinity. The organism could grow even at 30 ppt salinity with reduced biomass production and laccase secretion. The optimum concentration of different phenolic compounds for enhanced laccase secretion ranged between 20 and 80 mg L(-1) . As the concentration of phenolic compounds increased beyond 200 mg L(-1) , the enzyme activity decreased and was completely inhibited at 800 mg L(-1) . The tolerance of Trichoderma viride Pers. NFCCI-2745 to salinity and various phenolic compounds can be utilized in the bioremediation of highly saline and phenolic compound-rich industrial effluents. PMID:23712577

  13. Improved catalytic efficiency, thermophilicity, anti-salt and detergent tolerance of keratinase KerSMD by partially truncation of PPC domain.

    PubMed

    Fang, Zhen; Zhang, Juan; Du, Guocheng; Chen, Jian

    2016-01-01

    The keratinase from Stenotrophomonas maltophilia (KerSMD) is known for its high activity and pH stability in keratin degradation. However, catalytic efficiency and detergent tolerability need to be improved in order to be used for industrial application. In this work, we obtained several keratinase variants with enhanced catalytic efficiency, thermophilicity, and anti-salt and detergent tolerability by partially truncating the PPC domain of KerSMD. The variants all showed improved catalytic efficiency to synthetic substrate AAPF, with the V355 variant having the highest kcat /Km value of 143.6 s(-1) mM(-1). The truncation of keratinase had little effect on alkaline stability but obviously decreased collagenase activity, developing its potential application in leather treatment. The variants V380, V370, and V355 were thermophilic, with a 1.7-fold enhancement of keratinlytic activity at 60 °C when compared to the wild type. The entire truncation of PPC domain obtained the variant V355 with improved tolerance to alkalinity, salt, chaotropic agents, and detergents. The V355 variant showed more than a 40% improvement in activity under 15% (w/v) NaCl or 4% (w/v) SDS solution, showing excellent stability under harsh washing and unhairing conditions. Our work investigated how protein engineering affects the function of PPC domain of KerSMD. PMID:27298079

  14. Habituation of enterotoxigenic Staphylococcus aureus to Origanum vulgare L. essential oil does not induce direct-tolerance and cross-tolerance to salts and organic acids

    PubMed Central

    Tavares, Adassa Gama; do Monte, Daniel Farias Marinho; Albuquerque, Allan dos Reis; Sampaio, Fábio Correia; Magnani, Marciane; de Siqueira, José Pinto; de Souza, Evandro Leite

    2015-01-01

    Enterotoxigenic Staphylococcus aureus strains that were isolated from foods were investigated for their ability to develop direct-tolerance and cross-tolerance to sodium chloride (NaCl), potassium chloride (KCl), lactic acid (LA) and acetic acid (AA) after habituation in sublethal amounts (1/2 of the minimum inhibitory concentration - 1/2 MIC and 1/4 of the minimum inhibitory concentration - 1/4 MIC) of Origanum vulgare L. essential oil (OVEO). The habituation of S. aureus to 1/2 MIC and 1/4 MIC of OVEO did not induce direct-tolerance or cross-tolerance in the tested strains, as assessed by modulation of MIC values. Otherwise, exposing the strains to OVEO at sublethal concentrations maintained or increased the sensitivity of the cells to the tested stressing agents because the MIC values of OVEO, NaCl, KCl, LA and AA against the cells that were previously habituated to OVEO remained the same or decreased when compared with non-habituated cells. These data indicate that OVEO does not have an inductive effect on the acquisition of direct-tolerance or cross-tolerance in the tested enterotoxigenic strains of S. aureus to antimicrobial agents that are typically used in food preservation. PMID:26413067

  15. Caspase-like enzymatic activity and the ascorbate-glutathione cycle participate in salt stress tolerance of maize conferred by exogenously applied nitric oxide

    PubMed Central

    Keyster, Marshall; Klein, Ashwil; Ludidi, Ndiko

    2012-01-01

    Salinity stress causes ionic stress (mainly from high Na+ and Cl- levels) and osmotic stress (as a result of inhibition of water uptake by roots and amplified water loss from plant tissue), resulting in cell death and inhibition of growth and ultimately adversely reducing crop productivity. In this report, changes in root nitric oxide content, shoot and root biomass, root H2O2 content, root lipid peroxidation, root cell death, root caspase-like enzymatic activity, root antioxidant enzymatic activity and root ascorbate and glutathione contents/redox states were investigated in maize (Zea mays L. cv Silverking) after long-term (21 d) salt stress (150 mM NaCl) with or without exogenously applied nitric oxide generated from the nitric oxide donor 2,2′-(Hydroxynitrosohydrazano)bis-ethane. In addition to reduced shoot and root biomass, salt stress increased the nitric oxide and H2O2 contents in the maize roots and resulted in elevated lipid peroxidation, caspase-like activity and cell death in the roots. Altered antioxidant enzymatic activities, along with changes in ascorbate and glutathione contents/redox status were observed in the roots in response to salt stress. The detrimental effects of salt stress in the roots were reversed by exogenously applied nitric oxide. These results demonstrate that exogenously applied nitric oxide confers salt stress tolerance in maize by reducing salt stress-induced oxidative stress and caspase-like activity through a process that limits accumulation of reactive oxygen species via enhanced antioxidant enzymatic activity. PMID:22476534

  16. 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

  17. Virus-induced gene silencing reveals control of reactive oxygen species accumulation and salt tolerance in tomato by γ-aminobutyric acid metabolic pathway.

    PubMed

    Bao, Hexigeduleng; Chen, Xianyang; Lv, Sulian; Jiang, Ping; Feng, Juanjuan; Fan, Pengxiang; Nie, Lingling; Li, Yinxin

    2015-03-01

    γ-Aminobutyric acid (GABA) accumulates in many plant species in response to environmental stress. However, the physiological function of GABA or its metabolic pathway (GABA shunt) in plants remains largely unclear. Here, the genes, including glutamate decarboxylases (SlGADs), GABA transaminases (SlGABA-Ts) and succinic semialdehyde dehydrogenase (SlSSADH), controlling three steps of the metabolic pathway of GABA, were studied through virus-induced gene silencing approach in tomato. Silencing of SlGADs (GABA biosynthetic genes) and SlGABA-Ts (GABA catabolic genes) led to increased accumulation of reactive oxygen species (ROS) as well as salt sensitivity under 200 mm NaCl treatment. Targeted quantitative analysis of metabolites revealed that GABA decreased and increased in the SlGADs- and SlGABA-Ts-silenced plants, respectively, whereas succinate (the final product of GABA metabolism) decreased in both silenced plants. Contrarily, SlSSADH-silenced plants, also defective in GABA degradation process, showed dwarf phenotype, curled leaves and enhanced accumulation of ROS in normal conditions, suggesting the involvement of a bypath for succinic semialdehyde catabolism to γ-hydroxybutyrate as reported previously in Arabidopsis, were less sensitive to salt stress. These results suggest that GABA shunt is involved in salt tolerance of tomato, probably by affecting the homeostasis of metabolites such as succinate and γ-hydroxybutyrate and subsequent ROS accumulation under salt stress. PMID:25074245

  18. Expression of Stipa purpurea SpCIPK26 in Arabidopsis thaliana Enhances Salt and Drought Tolerance and Regulates Abscisic Acid Signaling.

    PubMed

    Zhou, Yanli; Sun, Xudong; Yang, Yunqiang; Li, Xiong; Cheng, Ying; Yang, Yongping

    2016-01-01

    Stipa purpurea (S. purpurea) is the dominant plant species in the alpine steppe of the Qinghai-Tibet Plateau, China. It is highly resistant to cold and drought conditions. However, the underlying mechanisms regulating the stress tolerance are unknown. In this study, a CIPK gene from S. purpurea (SpCIPK26) was isolated. The SpCIPK26 coding region consisted of 1392 bp that encoded 464 amino acids. The protein has a highly conserved catalytic structure and regulatory domain. The expression of SpCIPK26 was induced by drought and salt stress. SpCIPK26 overexpression in Arabidopsis thaliana (A. thaliana) plants provided increased tolerance to drought and salt stress in an abscisic acid (ABA)-dependent manner. Compared with wild-type A. thaliana plants, SpCIPK26-overexpressing plants had higher survival rates, water potentials, and photosynthetic efficiency (Fv/Fm), as well as lower levels of reactive oxygen species (ROS) following exposure to drought and salt stress. Gene expression analyses indicated stress-inducible genes (RD29A, RD29B, and ABF2) and a ROS-scavenger gene (CAT1) were upregulated in SpCIPK26-overexpressing plants after stress treatments. All of these marker genes are associated with ABA-responsive cis-acting elements. Additionally, the similarities in the gene expression patterns following ABA, mannitol, and NaCl treatments suggest SpCIPK26 has an important role during plant responses to drought and salt stress and in regulating ABA signaling. PMID:27338368

  19. Genome-wide analysis of AP2/ERF family genes from Lotus corniculatus shows LcERF054 enhances salt tolerance.

    PubMed

    Sun, Zhan-Min; Zhou, Mei-Liang; Xiao, Xing-Guo; Tang, Yi-Xiong; Wu, Yan-Min

    2014-09-01

    Lotus corniculatus is used in agriculture as a main forage plant. Members of the Apetala2/ethylene response factor (AP2/ERF) family play important roles in regulating gene expression in response to many forms of stress, including drought and salt. Here, starting from database of the L. corniculatus var. japonicus genome, we identified 127 AP2/ERF genes by insilico cloning method. The phylogeny, gene structures, and putative conserved motifs in L. corniculatus var. japonicus ERF proteins were analyzed. Based on the number of AP2/ERF domains and the function of the genes, 127 AP2/ERF genes from L. corniculatus var. japonicus were classified into five subfamilies named the AP2, dehydration-responsive element binding factor (DREB), ERF, RAV, and a soloist. Outside the AP2/ERF domain, many L. corniculatus var. japonicus-specific conserved motifs were detected. Expression profile analysis of AP2/ERF genes by quantitative real-time PCR revealed that 19 LcERF genes, including LcERF054 (KJ004728), were significantly induced by salt stress. The results showed that the LcERF054 gene encodes a nuclear transcription activator. Overexpression of LcERF054 in Arabidopsis enhanced the tolerances to salt stress, showed higher germination ratio of seeds, and had elevated levels of relative moisture contents, soluble sugars, proline, and lower levels of malondialdehyde under stress conditions compared to wild-type plants. The expression of hyperosmotic salinity response genes COR15A, LEA4-5, P5CS1, and RD29A was found to be elevated in the LcERF054-overexpressing Arabidopsis plants compared to wild type. These results revealed that the LcERF genes play important roles in L. corniculatus cv Leo under salt stress and that LcERFs are attractive engineering targets in applied efforts to improve abiotic stress tolerances in L. corniculatus cv Leo or other crops. PMID:24777608

  20. Expression of Stipa purpurea SpCIPK26 in Arabidopsis thaliana Enhances Salt and Drought Tolerance and Regulates Abscisic Acid Signaling

    PubMed Central

    Zhou, Yanli; Sun, Xudong; Yang, Yunqiang; Li, Xiong; Cheng, Ying; Yang, Yongping

    2016-01-01

    Stipa purpurea (S. purpurea) is the dominant plant species in the alpine steppe of the Qinghai-Tibet Plateau, China. It is highly resistant to cold and drought conditions. However, the underlying mechanisms regulating the stress tolerance are unknown. In this study, a CIPK gene from S. purpurea (SpCIPK26) was isolated. The SpCIPK26 coding region consisted of 1392 bp that encoded 464 amino acids. The protein has a highly conserved catalytic structure and regulatory domain. The expression of SpCIPK26 was induced by drought and salt stress. SpCIPK26 overexpression in Arabidopsis thaliana (A. thaliana) plants provided increased tolerance to drought and salt stress in an abscisic acid (ABA)-dependent manner. Compared with wild-type A. thaliana plants, SpCIPK26-overexpressing plants had higher survival rates, water potentials, and photosynthetic efficiency (Fv/Fm), as well as lower levels of reactive oxygen species (ROS) following exposure to drought and salt stress. Gene expression analyses indicated stress-inducible genes (RD29A, RD29B, and ABF2) and a ROS-scavenger gene (CAT1) were upregulated in SpCIPK26-overexpressing plants after stress treatments. All of these marker genes are associated with ABA-responsive cis-acting elements. Additionally, the similarities in the gene expression patterns following ABA, mannitol, and NaCl treatments suggest SpCIPK26 has an important role during plant responses to drought and salt stress and in regulating ABA signaling. PMID:27338368

  1. Overexpression of a cotton (Gossypium hirsutum) WRKY gene, GhWRKY34, in Arabidopsis enhances salt-tolerance of the transgenic plants.

    PubMed

    Zhou, Li; Wang, Na-Na; Gong, Si-Ying; Lu, Rui; Li, Yang; Li, Xue-Bao

    2015-11-01

    Soil salinity is one of the most serious threats in world agriculture, and often influences cotton growth and development, resulting in a significant loss in cotton crop yield. WRKY transcription factors are involved in plant response to high salinity stress, but little is known about the role of WRKY transcription factors in cotton so far. In this study, a member (GhWRKY34) of cotton WRKY family was functionally characterized. This protein containing a WRKY domain and a zinc-finger motif belongs to group III of cotton WRKY family. Subcellular localization assay indicated that GhWRKY34 is localized to the cell nucleus. Overexpression of GhWRKY34 in Arabidopsis enhanced the transgenic plant tolerance to salt stress. Several parameters (such as seed germination, green cotyledons, root length and chlorophyll content) in the GhWRKY34 transgenic lines were significantly higher than those in wild type under NaCl treatment. On the contrary, the GhWRKY34 transgenic plants exhibited a substantially lower ratio of Na(+)/K(+) in leaves and roots dealing with salt stress, compared with wild type. Growth status of the GhWRKY34 transgenic plants was much better than that of wild type under salt stress. Expressions of the stress-related genes were remarkably up-regulated in the transgenic plants under salt stress, compared with those in wild type. Based on the data presented in this study, we hypothesize that GhWRKY34 as a positive transcription regulator may function in plant response to high salinity stress through maintaining the Na(+)/K(+) homeostasis as well as activating the salt stress-related genes in cells. PMID:26332661

  2. Does Salicylic Acid (SA) Improve Tolerance to Salt Stress in Plants? A Study of SA Effects On Tomato Plant Growth, Water Dynamics, Photosynthesis, and Biochemical Parameters.

    PubMed

    Mimouni, Hajer; Wasti, Salma; Manaa, Arafet; Gharbi, Emna; Chalh, Abdellah; Vandoorne, Bertrand; Lutts, Stanley; Ben Ahmed, Hela

    2016-03-01

    Environmental stresses such as salinity directly impact crop growth, and by extension, world food supply and societal prosperity. It is estimated that over 800 million hectares of land throughout the world are salt-affected. In arid and semi-arid regions, salt concentration can be close to that in the seawater. Hence, there are intensive efforts to improve plant tolerance to salinity and other environmental stressors. Salicylic acid (SA) is an important signal molecule for modulating plant responses to stress. In the present study, we examined, on multiple plant growth related endpoints, whether SA applied through the rooting medium could mitigate the adverse effects of salinity on tomato (Solanum lycopersicum) cv. Marmande. The latter is a hitherto understudied tomato plant from the above perspective; it is a classic variety that produces the large ribbed tomatoes in the Mediterranean and consumed worldwide. We found salt stress negatively affected the growth of cv. Marmande tomato plants. However, the SA-treated plants had greater shoot and root dry mass, leaf area compared to untreated plants when exposed to salt stress. Application of SA restores photosynthetic rates and photosynthetic pigment levels under salt (NaCl) exposure. Leaf water, osmotic potential, stomatal conductance transpiration rate, and biochemical parameters were also ameliorated in SA-treated plants under saline stress conditions. Overall, these data illustrate that SA increases cv. Marmande tomato growth by improving photosynthesis, regulation and balance of osmotic potential, induction of compatible osmolyte metabolism, and alleviating membrane damage. We suggest salicylic acid might be considered as a potential growth regulator to improve tomato plant salinity stress resistance, in the current era of global climate change. PMID:26909467

  3. The Rice High-Affinity Potassium Transporter1;1 Is Involved in Salt Tolerance and Regulated by an MYB-Type Transcription Factor1[OPEN

    PubMed Central

    Wang, Rong; Jing, Wen; Jin, Yakang; Shen, Like

    2015-01-01

    Sodium transporters play key roles in plant tolerance to salt stress. Here, we report that a member of the High-Affinity K+ Transporter (HKT) family, OsHKT1;1, in rice (Oryza sativa ‘Nipponbare’) plays an important role in reducing Na+ accumulation in shoots to cope with salt stress. The oshkt1;1 mutant plants displayed hypersensitivity to salt stress. They contained less Na+ in the phloem sap and accumulated more Na+ in the shoots compared with the wild type. OsHKT1;1 was expressed mainly in the phloem of leaf blades and up-regulated in response to salt stress. Using a yeast one-hybrid approach, a novel MYB coiled-coil type transcription factor, OsMYBc, was found to bind to the OsHKT1;1 promoter. In vivo chromatin immunoprecipitation and in vitro electrophoresis mobility shift assays demonstrated that OsMYBc binds to AAANATNC(C/T) fragments within the OsHKT1;1 promoter. Mutation of the OsMYBc-binding nucleotides resulted in a decrease in promoter activity of OsHKT1;1. Knockout of OsMYBc resulted in a reduction in NaCl-induced expression of OsHKT1;1 and salt sensitivity. Taken together, these results suggest that OsHKT1;1 has a role in controlling Na+ concentration and preventing sodium toxicity in leaf blades and is regulated by the OsMYBc transcription factor. PMID:25991736

  4. Two wheat glutathione peroxidase genes whose products are located in chloroplasts improve salt and H2O2 tolerances in Arabidopsis.

    PubMed

    Zhai, Chao-Zeng; Zhao, Lei; Yin, Li-Juan; Chen, Ming; Wang, Qing-Yu; Li, Lian-Cheng; Xu, Zhao-Shi; Ma, You-Zhi

    2013-01-01

    Oxidative stress caused by accumulation of reactive oxygen species (ROS) is capable of damaging effects on numerous cellular components. Glutathione peroxidases (GPXs, EC 1.11.1.9) are key enzymes of the antioxidant network in plants. In this study, W69 and W106, two putative GPX genes, were obtained by de novo transcriptome sequencing of salt-treated wheat (Triticum aestivum) seedlings. The purified His-tag fusion proteins of W69 and W106 reduced H2O2 and t-butyl hydroperoxide (t-BHP) using glutathione (GSH) or thioredoxin (Trx) as an electron donor in vitro, showing their peroxidase activity toward H2O2 and toxic organic hydroperoxide. GFP fluorescence assays revealed that W69 and W106 are localized in chloroplasts. Quantitative real-time PCR (Q-RT-PCR) analysis showed that two GPXs were differentially responsive to salt, drought, H2O2, or ABA. Isolation of the W69 and W106 promoters revealed some cis-acting elements responding to abiotic stresses. Overexpression of W69 and W106 conferred strong tolerance to salt, H2O2, and ABA treatment in Arabidopsis. Moreover, the expression levels of key regulator genes (SOS1, RbohD and ABI1/ABI2) involved in salt, H2O2 and ABA signaling were altered in the transgenic plants. These findings suggest that W69 and W106 not only act as scavengers of H2O2 in controlling abiotic stress responses, but also play important roles in salt and ABA signaling. PMID:24098330

  5. The Rice High-Affinity Potassium Transporter1;1 Is Involved in Salt Tolerance and Regulated by an MYB-Type Transcription Factor.

    PubMed

    Wang, Rong; Jing, Wen; Xiao, Longyun; Jin, Yakang; Shen, Like; Zhang, Wenhua

    2015-07-01

    Sodium transporters play key roles in plant tolerance to salt stress. Here, we report that a member of the High-Affinity K(+) Transporter (HKT) family, OsHKT1;1, in rice (Oryza sativa 'Nipponbare') plays an important role in reducing Na(+) accumulation in shoots to cope with salt stress. The oshkt1;1 mutant plants displayed hypersensitivity to salt stress. They contained less Na(+) in the phloem sap and accumulated more Na(+) in the shoots compared with the wild type. OsHKT1;1 was expressed mainly in the phloem of leaf blades and up-regulated in response to salt stress. Using a yeast one-hybrid approach, a novel MYB coiled-coil type transcription factor, OsMYBc, was found to bind to the OsHKT1;1 promoter. In vivo chromatin immunoprecipitation and in vitro electrophoresis mobility shift assays demonstrated that OsMYBc binds to AAANATNC(C/T) fragments within the OsHKT1;1 promoter. Mutation of the OsMYBc-binding nucleotides resulted in a decrease in promoter activity of OsHKT1;1. Knockout of OsMYBc resulted in a reduction in NaCl-induced expression of OsHKT1;1 and salt sensitivity. Taken together, these results suggest that OsHKT1;1 has a role in controlling Na(+) concentration and preventing sodium toxicity in leaf blades and is regulated by the OsMYBc transcription factor. PMID:25991736

  6. From QTL to variety-harnessing the benefits of QTLs for drought, flood and salt tolerance in mega rice varieties of India through a multi-institutional network.

    PubMed

    Singh, Renu; Singh, Yashi; Xalaxo, Suchit; Verulkar, S; Yadav, Neera; Singh, Shweta; Singh, Nisha; Prasad, K S N; Kondayya, K; Rao, P V Ramana; Rani, M Girija; Anuradha, T; Suraynarayana, Y; Sharma, P C; Krishnamurthy, S L; Sharma, S K; Dwivedi, J L; Singh, A K; Singh, P K; Nilanjay; Singh, N K; Kumar, Rajesh; Chetia, S K; Ahmad, T; Rai, M; Perraju, P; Pande, Anita; Singh, D N; Mandal, N P; Reddy, J N; Singh, O N; Katara, J L; Marandi, B; Swain, P; Sarkar, R K; Singh, D P; Mohapatra, T; Padmawathi, G; Ram, T; Kathiresan, R M; Paramsivam, K; Nadarajan, S; Thirumeni, S; Nagarajan, M; Singh, A K; Vikram, Prashant; Kumar, Arvind; Septiningshih, E; Singh, U S; Ismail, A M; Mackill, D; Singh, Nagendra K

    2016-01-01

    Rice is a staple cereal of India cultivated in about 43.5Mha area but with relatively low average productivity. Abiotic factors like drought, flood and salinity affect rice production adversely in more than 50% of this area. Breeding rice varieties with inbuilt tolerance to these stresses offers an economically viable and sustainable option to improve rice productivity. Availability of high quality reference genome sequence of rice, knowledge of exact position of genes/QTLs governing tolerance to abiotic stresses and availability of DNA markers linked to these traits has opened up opportunities for breeders to transfer the favorable alleles into widely grown rice varieties through marker-assisted backcross breeding (MABB). A large multi-institutional project, "From QTL to variety: marker-assisted breeding of abiotic stress tolerant rice varieties with major QTLs for drought, submergence and salt tolerance" was initiated in 2010 with funding support from Department of Biotechnology, Government of India, in collaboration with International Rice Research Institute, Philippines. The main focus of this project is to improve rice productivity in the fragile ecosystems of eastern, northeastern and southern part of the country, which bear the brunt of one or the other abiotic stresses frequently. Seven consistent QTLs for grain yield under drought, namely, qDTY1.1, qDTY2.1, qDTY2.2, qDTY3.1, qDTY3.2, qDTY9.1 and qDTY12.1 are being transferred into submergence tolerant versions of three high yielding mega rice varieties, Swarna-Sub1, Samba Mahsuri-Sub1 and IR 64-Sub1. To address the problem of complete submergence due to flash floods in the major river basins, the Sub1 gene is being transferred into ten highly popular locally adapted rice varieties namely, ADT 39, ADT 46, Bahadur, HUR 105, MTU 1075, Pooja, Pratikshya, Rajendra Mahsuri, Ranjit, and Sarjoo 52. Further, to address the problem of soil salinity, Saltol, a major QTL for salt tolerance is being transferred into

  7. Overexpression of an Arabidopsis heterogeneous nuclear ribonucleoprotein gene, AtRNP1, affects plant growth and reduces plant tolerance to drought and salt stresses.

    PubMed

    Wang, Zhenyu; Zhao, Xiuyang; Wang, Bing; Liu, Erlong; Chen, Ni; Zhang, Wei; Liu, Heng

    2016-04-01

    Heterogeneous nuclear ribonucleoproteins (hnRNPs) participate in diverse regulations of plant growth and environmental stress responses. In this work, an Arabidopsis hnRNP of unknown function, AtRNP1, was investigated. We found that AtRNP1 gene is highly expressed in rosette and cauline leaves, and slightly induced under drought, salt, osmotic and ABA stresses. AtRNP1 protein is localized to both the nucleus and cytoplasm. We performed homologous overexpression of AtRNP1 and found that the transgenic plants showed shortened root length and plant height, and accelerated flowering. In addition, the transgenic plants also showed reduced tolerance to drought, salt, osmotic and ABA stresses. Further studies revealed that under both normal and stress conditions, the proline contents in the transgenic plants are markedly decreased, associated with reduced expression levels of a proline synthase gene and several stress-responsive genes. These results suggested that the overexpression of AtRNP1 negatively affects plant growth and abiotic stress tolerance. PMID:26923071

  8. Heterologous expression of Lactobacillus casei RecO improved the multiple-stress tolerance and lactic acid production in Lactococcus lactis NZ9000 during salt stress.

    PubMed

    Wu, Chongde; Zhang, Juan; Du, Guocheng; Chen, Jian

    2013-09-01

    The aim of this study was to investigate the effect of nisin-inducible RecO expression on the stress tolerance of Lactococcus lactis NZ9000. RecO protein from Lactobacillus casei Zhang was introduced into Lactococcus lactis NZ9000 by using a nisin-inducible expression system. The recombinant strain (NZ-RecO) exhibited higher growth performances and survival rate compared with the control strain (NZ-Vector) under stress conditions. In addition, the NZ-RecO strain exhibited 1.37-, 1.41-, and 1.42-fold higher biomass, lactate production, lactate productivity, compared with the corresponding values for NZ-Vector during NaCl-stressed condition. Analysis of lactate dehydrogenase (LDH) activity showed that the production of RecO maintained the stability of LDH during salt stress. These results suggest that overproduction of RecO improved the multiple-stress tolerance and lactic acid production in Lactococcus lactis NZ9000 during salt stress. Results presented in this study may help to enhance the industrial utility of lactic acid bacteria. PMID:23796607

  9. Glucose-6-phosphate dehydrogenase and alternative oxidase are involved in the cross tolerance of highland barley to salt stress and UV-B radiation.

    PubMed

    Zhao, Chengzhou; Wang, Xiaomin; Wang, Xiaoyu; Wu, Kunlun; Li, Ping; Chang, Ning; Wang, Jianfeng; Wang, Feng; Li, Jiaolong; Bi, Yurong

    2015-06-01

    In this study, a new mechanism involving glucose-6-phosphate dehydrogenase (G6PDH) and alternative pathways (AP) in salt pretreatment-induced tolerance of highland barley to UV-B radiation was investigated. When highland barley was exposed to UV-B radiation, the G6PDH activity decreased but the AP capacity increased. In contrast, under UV-B+NaCl treatment, the G6PDH activity was restored to the control level and the maximal AP capacity and antioxidant enzyme activities were reached. Glucosamine (Glucm, an inhibitor of G6PDH) obviously inhibited the G6PDH activity in highland barley under UV-B + NaCl treatment and a similar pattern was observed in reduced glutathione (GSH) and ascorbic acid (Asc) contents. Similarly, salicylhydroxamic acid (SHAM, an inhibitor of AOX) significantly reduced the AP capacity in highland barley under UV-B + NaCl treatment. The UV-B-induced hydrogen peroxide (H2O2) accumulation was also followed. Further studies indicated that non-functioning of G6PDH or AP under UV-B+NaCl + Glucm or UV-B + NaCl + SHAM treatment also caused damages in photosynthesis and stomatal movement. Western blot analysis confirmed that the alternative oxidase (AOX) and G6PDH were dependent each other in cross tolerance to UV-B and salt. The inhibition of AP or G6PDH activity resulted in a significant accumulation or reduction of NADPH content, respectively, under UV-B+NaCl treatment in highland barley leaves. Taken together, our results indicate that AP and G6PDH mutually regulate and maintain photosynthesis and stomata movement in the cross adaptation of highland barley seedlings to UV-B and salt by modulating redox homeostasis and NADPH content. PMID:26009793

  10. Capsicum annuum homeobox 1 (CaHB1) is a nuclear factor that has roles in plant development, salt tolerance, and pathogen defense

    SciTech Connect

    Oh, Sang-Keun; Yoon, Joonseon; Choi, Gyung Ja; Jang, Hyun A; Kwon, Suk-Yoon; Choi, Doil

    2013-12-06

    Highlights: •The CaHB1 is a nuclear factor, belonging to HD-Zip proteins. •SA and ET, as signal molecules, modulate CaHB1-mediated responses. •Overexpression of CaHB1 in tomato resulted in a thicker cell wall. •CaHB1-transgenic tomato confers resistance to Phytophthora infestans. •CaHB1 enhanced tolerance to saline stress in tomato. -- Abstract: Homeodomain-leucine zipper (HD-Zip) family proteins are unique to plants, but little is known about their role in defense responses. CaHB1 is a nuclear factor in peppers, belonging to subfamily II of HD-Zip proteins. Here, we determined the role of CaHB1 in the defense response. CaHB1 expression was induced when pepper plants were challenged with Phytophthora capsici, a plant pathogen to which peppers are susceptible, or environmental stresses such as drought and salt stimuli. CaHB1 was also highly expressed in pepper leaves following application of SA, whereas ethephon and MeJA had a moderate effect. To further investigate the function of CaHB1 in plants, we performed gain-of-function study by overexpression of CaHB1 in tomato. CaHB1-transgenic tomatoes showed significant growth enhancement including increased leaf thickness and enlarged cell size (1.8-fold larger than control plants). Microscopic analysis revealed that leaves from CaHB1-transgenic plants had thicker cell walls and cuticle layers than those from controls. Moreover, CaHB1-transgenic plants displayed enhanced resistance against Phytophthora infestans and increased tolerance to salt stress. Additionally, RT-PCR analysis of CaHB1-transgenic tomatoes revealed constitutive up-regulation of multiple genes involved in plant defense and osmotic stress. Therefore, our findings suggest roles for CaHB1 in development, salt stress, and pathogen defense.

  11. 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

  12. A New AP2/ERF Transcription Factor from the Oil Plant Jatropha curcas Confers Salt and Drought Tolerance to Transgenic Tobacco.

    PubMed

    Wang, Xuehua; Han, Haiyang; Yan, Jun; Chen, Fang; Wei, Wei

    2015-05-01

    Jatropha curcas L. is a drought and salt-tolerant oil plant widely used for various purposes and has considerable potential as a diesel/kerosene substitute or extender. Understanding the molecular mechanisms underlie that the response to various biotic and abiotic stresses of this plant could be important to crop improvement efforts. Here, a new AP2/ERF-type transcription factor gene, named JcERF2, was isolated from the leaves of J. curcas. Sequence analysis showed that the JcERF2 gene contains a 759-bp open reading frame encoding a polypeptide of 252 amino acids. The predicted JcERF2 protein contained a conserved DNA-binding domain (the AP2/ERF domain) with 58 amino acids. The JcERF2 protein is highly homologous with other ERFs. JcERF2 was localized in the nucleus by analysis with a JcERF2-green fluorescent protein (GFP) fusion protein. Quantitative polymerase chain reaction (qPCR) analysis showed that JcERF2 was induced by drought, salt, abscisic acid, and ethylene. Overexpression of JcERF2 in transgenic tobacco plants enhanced the expression of biotic and abiotic stress-related genes, increased the accumulation of free proline and soluble carbohydrates, and conferred tolerance to drought and salt stresses compared to the wild type (WT). Taken together, the JcERF2 gene is a novel AP2/ERF transcription factor involved in plant response to environmental factors, which can be used as a potential candidate gene for genetic engineering of crops. PMID:25935218

  13. A myo-inositol-1-phosphate synthase gene, IbMIPS1, enhances salt and drought tolerance and stem nematode resistance in transgenic sweet potato.

    PubMed

    Zhai, Hong; Wang, Feibing; Si, Zengzhi; Huo, Jinxi; Xing, Lei; An, Yanyan; He, Shaozhen; Liu, Qingchang

    2016-02-01

    Myo-inositol-1-phosphate synthase (MIPS) is a key rate limiting enzyme in myo-inositol biosynthesis. The MIPS gene has been shown to improve tolerance to abiotic stresses in several plant species. However, its role in resistance to biotic stresses has not been reported. In this study, we found that expression of the sweet potato IbMIPS1 gene was induced by NaCl, polyethylene glycol (PEG), abscisic acid (ABA) and stem nematodes. Its overexpression significantly enhanced stem nematode resistance as well as salt and drought tolerance in transgenic sweet potato under field conditions. Transcriptome and real-time quantitative PCR analyses showed that overexpression of IbMIPS1 up-regulated the genes involved in inositol biosynthesis, phosphatidylinositol (PI) and ABA signalling pathways, stress responses, photosynthesis and ROS-scavenging system under salt, drought and stem nematode stresses. Inositol, inositol-1,4,5-trisphosphate (IP3 ), phosphatidic acid (PA), Ca(2+) , ABA, K(+) , proline and trehalose content was significantly increased, whereas malonaldehyde (MDA), Na(+) and H2 O2 content was significantly decreased in the transgenic plants under salt and drought stresses. After stem nematode infection, the significant increase of inositol, IP3 , PA, Ca(2+) , ABA, callose and lignin content and significant reduction of MDA content were found, and a rapid increase of H2 O2 levels was observed, peaked at 1 to 2 days and thereafter declined in the transgenic plants. This study indicates that the IbMIPS1 gene has the potential to be used to improve the resistance to biotic and abiotic stresses in plants. PMID:26011089

  14. Is salt stress tolerance in Casuarina glauca Sieb. ex Spreng. associated with its nitrogen-fixing root-nodule symbiosis? An analysis at the photosynthetic level.

    PubMed

    Batista-Santos, Paula; Duro, Nuno; Rodrigues, Ana P; Semedo, José N; Alves, Paula; da Costa, Mário; Graça, Inês; Pais, Isabel P; Scotti-Campos, Paula; Lidon, Fernando C; Leitão, António E; Pawlowski, Katharina; Ribeiro-Barros, Ana I; Ramalho, José C

    2015-11-01

    Casuarina glauca is an actinorhizal tree which establishes root-nodule symbiosis with N2-fixing Frankia bacteria. This plant is commonly found in saline zones and is widely used to remediate marginal soils and prevent desertification. The nature of its ability to survive in extreme environments and the extent of Frankia contribution to stress tolerance remain unknown. Thus, we evaluated the ability of C. glauca to cope with salt stress and the influence of the symbiosis on this trait. To this end, we analysed the impact of salt on plant growth, mineral contents, water relations, photosynthetic-related parameters and non-structural sugars in nodulated vs. non-nodulated plants. Although the effects on photosynthesis and stomatal conductance started to become measurable in the presence of 200 mM NaCl, photochemical (e.g., photosynthetic electron flow) and biochemical (e.g., activity of photosynthetic enzymes) parameters were only strongly impaired when NaCl levels reached 600 mM. These results indicate the maintenance of high tissue hydration under salt stress, probably associated with enhanced osmotic potential. Furthermore, the maintenance of photosynthetic assimilation potential (A(max)), together with the increase in the quantum yield of down-regulated energy dissipation of PSII (Y(NPQ)), suggested a down-regulation of photosynthesis instead of photo-damaging effects. A comparison of the impact of increasing NaCl levels on the activities of photosynthetic (RubisCO and ribulose-5 phosphate kinase) and respiratory (pyruvate kinase and NADH-dependent malate dehydrogenase) enzymes vs. photosynthetic electron flow and fluorescence parameters, revealed that biochemical impairments are more limiting than photochemical damage. Altogether, these results indicate that, under controlled conditions, C. glauca tolerates high NaCl levels and that this capacity is linked to photosynthetic adjustments. PMID:26245981

  15. Overexpression of a Populus trichocarpa H+-pyrophosphatase gene PtVP1.1 confers salt tolerance on transgenic poplar.

    PubMed

    Yang, Y; Tang, R J; Li, B; Wang, H H; Jin, Y L; Jiang, C M; Bao, Y; Su, H Y; Zhao, N; Ma, X J; Yang, L; Chen, S L; Cheng, X H; Zhang, H X

    2015-06-01

    The Arabidopsis vacuolar H(+)-pyrophosphatase (AVP1) has been well studied and subsequently employed to improve salt and/or drought resistance in herbaceous plants. However, the exact function of H(+)-pyrophosphatase in woody plants still remains unknown. In this work, we cloned a homolog of type I H(+)-pyrophosphatase gene, designated as PtVP1.1, from Populus trichocarpa, and investigated its function in both Arabidopsis and poplar. The deduced translation product PtVP1.1 shares 89.74% identity with AVP1. Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) and quantitative real-time PCR analyses revealed a ubiquitous expression pattern of PtVP1.1 in various tissues, including roots, stems, leaves and shoot tips. Heterologous expression of PtVP1.1 rescued the retarded-root-growth phenotype of avp1, an Arabidopsis knock out mutant of AVP1, on low carbohydrate medium. Overexpression of PtVP1.1 in poplar (P. davidiana × P. bolleana) led to more vigorous growth of transgenic plants in the presence of 150 mM NaCl. Microsomal membrane vesicles derived from PtVP1.1 transgenic plants exhibited higher H(+)-pyrophosphatase hydrolytic activity than those from wild type (WT). Further studies indicated that the improved salt tolerance was associated with a decreased Na(+) and increased K(+) accumulation in the leaves of transgenic plants. Na(+) efflux and H(+) influx in the roots of transgenic plants were also significantly higher than those in the WT plants. All these results suggest that PtVP1.1 is a functional counterpart of AVP1 and can be genetically engineered for salt tolerance improvement in trees. PMID:25877769

  16. Rice potassium transporter OsHAK1 is essential for maintaining potassium-mediated growth and functions in salt tolerance over low and high potassium concentration ranges.

    PubMed

    Chen, Guang; Hu, Qingdi; Luo, Le; Yang, Tianyuan; Zhang, Song; Hu, Yibing; Yu, Ling; Xu, Guohua

    2015-12-01

    Potassium (K) absorption and translocation in plants rely upon multiple K transporters for adapting varied K supply and saline conditions. Here, we report the expression patterns and physiological roles of OsHAK1, a member belonging to the KT/KUP/HAK gene family in rice (Oryza sativa L.). The expression of OsHAK1 is up-regulated by K deficiency or salt stress in various tissues, particularly in the root and shoot apical meristem, the epidermises and steles of root, and vascular bundles of shoot. Both oshak1 knockout mutants in comparison to their respective Dongjin or Manan wild types showed a dramatic reduction in K concentration and stunted root and shoot growth. Knockout of OsHAK1 reduced the K absorption rate of unit root surface area by ∼50-55 and ∼30%, and total K uptake by ∼80 and ∼65% at 0.05-0.1 and 1 mm K supply level, respectively. The root net high-affinity K uptake of oshak1 mutants was sensitive to salt stress but not to ammonium supply. Overexpression of OsHAK1 in rice increased K uptake and K/Na ratio. The positive relationship between K concentration and shoot biomass in the mutants suggests that OsHAK1 plays an essential role in K-mediated rice growth and salt tolerance over low and high K concentration ranges. PMID:26046301

  17. Detoxification of Eucheuma spinosum Hydrolysates with Activated Carbon for Ethanol Production by the Salt-Tolerant Yeast Candida tropicalis.

    PubMed

    Ra, Chae Hun; Jung, Jang Hyun; Sunwoo, In Young; Kang, Chang Han; Jeong, Gwi-Taek; Kim, Sung-Koo

    2015-06-01

    The objective of this study was to optimize the slurry contents and salt concentrations for ethanol production from hydrolysates of the seaweed Eucheuma spinosum. A monosaccharide concentration of 44.2 g/l as 49.6% conversion of total carbohydrate of 89.1 g/l was obtained from 120 g dw/l seaweed slurry. Monosaccharides from E. spinosum slurry were obtained by thermal acid hydrolysis and enzymatic hydrolysis. Addition of activated carbon at 2.5% (w/v) and the adsorption time of 2 min were used in subsequent adsorption treatments to prevent the inhibitory effect of HMF. The adsorption surface area of the activated carbon powder was 1,400-1,600 m(2)/g and showed selectivity to 5-hydroxymethyl furfural (HMF) from monosaccharides. Candida tropicalis KCTC 7212 was cultured in yeast extract, peptone, glucose, and high-salt medium, and exposed to 80, 90, 100, and 110 practical salinity unit (psu) salt concentrations in the lysates. The 100 psu salt concentration showed maximum cell growth and ethanol production. The ethanol fermentations with activated carbon treatment and use of C. tropicalis acclimated to a high salt concentration of 100 psu produced 17.9 g/l of ethanol with a yield (YEtOH) of 0.40 from E. spinosum seaweed. PMID:25649983

  18. PM2, a group 3 LEA protein from soybean, and its 22-mer repeating region confer salt tolerance in Escherichia coli

    SciTech Connect

    Yun Liu; Zheng Yizhi . E-mail: yzzheng@szu.edu.cn

    2005-05-27

    To have knowledge of the effect of soybean PM2 protein in protecting dehydrated cells and its functional region, PM2 cDNA was isolated from soybean immature seeds. The recombinants expressing full-length PM2, truncated polypeptides of PM2A (aa 1-262) or PM2B (aa 129-262, 22-mer repeating region), or artificial polypeptide PM2C (duplication of 22-mer repeating region) were constructed. By using SDS-PAGE and mass spectrometry approaches, these fusion polypeptides were identified and proved to be hydrophilic and heat-stable. Spot assays of BL/PM2 and BL/pET28 (as control) showed that protein PM2 increased salt tolerance (500 mM NaCl or 500 mM KCl) of Escherichia coli, rather than osmotic tolerance (1100 mM sorbitol). In addition, comparing the survival ratios of the transformants under 500 mM NaCl or 500 mM KCl stresses, the results showed that: (1) the survival ratios of BL/PM2 and BL/PM2B were quite similar, both showing much higher values than those of BL/pET28. (2) The survival ratios of BL/PM2C were much higher than those of BL/PM2, BL/PM2A, and BL/PM2B. This provides the first experimental evidence that PM2 polypeptide enhances salt tolerance of E. coli cells, and the 22-mer repeat region is an important functional region.

  19. Ure2 is involved in nitrogen catabolite repression and salt tolerance via Ca2+ homeostasis and calcineurin activation in the yeast Hansenula polymorpha.

    PubMed

    Rodríguez, Celia; Tejera, Paula; Medina, Braulio; Guillén, Rosa; Domínguez, Angel; Ramos, José; Siverio, José M

    2010-11-26

    Disruption of HpURE2 resulted in a low expression of genes encoding nitrate-assimilatory proteins; sensitivity to Li(+), Na(+), and Cd(2+); no induction of ENA1; low levels of the GATA-type transcription factor Gat1; and low intracellular Ca(2+) levels. Gat1 levels were also very low in a Δcnb1 mutant lacking the regulatory subunit of calcineurin. The strain Δure2 was very sensitive to the calcineurin inhibitor FK506 and displayed several phenotypes reminiscent of Δcnb1. The reporter 4xCDRE-lacZ, containing calcineurin-dependent response elements in its promoter, revealed that calcineurin activation was reduced in HpΔure2. Expression of ScURE2 in Δure2 rescued nitrogen catabolite repression and Cd(2+) tolerance but not those phenotypes depending on calcineurin activation, such as salt tolerance and nitrate assimilation gene derepression. HpΔure2 showed an increased expression of the gene PMR1 encoding the Golgi Ca(2+)-ATPase, whereas that of PMC1 encoding the vacuolar Ca(2+)-ATPase remained unaltered. PMR1 up-regulation was abolished by deletion of the GATA-type transcription factor GAT2 in a HpΔure2 genetic background, and normal Ca(2+) levels were recovered. Moreover, overexpression of GAT2 or PMR1 yielded strains mimicking the phenotype of the HpΔure2. This suggests that the low Ca(2+) levels in the HpΔure2 mutant are due to the high levels of Pmr1 that replenish the Golgi Ca(2+) content, thus acting as a negative signal for Ca(2+) entry into the cell. We conclude that HpUre2 is involved in salt tolerance and also in nitrate assimilation gene derepression via Ca(2+) homeostasis regulation and calcineurin activation, which control the levels of Gat1. PMID:20880842

  20. The SbASR-1 gene cloned from an extreme halophyte Salicornia brachiata enhances salt tolerance in transgenic tobacco.

    PubMed

    Jha, Bhavanath; Lal, Sanjay; Tiwari, Vivekanand; Yadav, Sweta Kumari; Agarwal, Pradeep K

    2012-12-01

    Salinity severely affects plant growth and development. Plants evolved various mechanisms to cope up stress both at molecular and cellular levels. Halophytes have developed better mechanism to alleviate the salt stress than glycophytes, and therefore, it is advantageous to study the role of different genes from halophytes. Salicornia brachiata is an extreme halophyte, which grows luxuriantly in the salty marshes in the coastal areas. Earlier, we have isolated SbASR-1 (abscisic acid stress ripening-1) gene from S. brachiata using cDNA subtractive hybridisation library. ASR-1 genes are abscisic acid (ABA) responsive, whose expression level increases under abiotic stresses, injury, during fruit ripening and in pollen grains. The SbASR-1 transcript showed up-regulation under salt stress conditions. The SbASR-1 protein contains 202 amino acids of 21.01-kDa molecular mass and has 79 amino acid long signatures of ABA/WDS gene family. It has a maximum identity (73 %) with Solanum chilense ASR-1 protein. The SbASR-1 has a large number of disorder-promoting amino acids, which make it an intrinsically disordered protein. The SbASR-1 gene was over-expressed under CaMV 35S promoter in tobacco plant to study its physiological functions under salt stress. T(0) transgenic tobacco seeds showed better germination and seedling growth as compared to wild type (Wt) in a salt stress condition. In the leaf tissues of transgenic lines, Na(+) and proline contents were significantly lower, as compared to Wt plant, under salt treatment, suggesting that transgenic plants are better adapted to salt stress. PMID:22639284

  1. MAOHUZI6/ETHYLENE INSENSITIVE3-LIKE1 and ETHYLENE INSENSITIVE3-LIKE2 Regulate Ethylene Response of Roots and Coleoptiles and Negatively Affect Salt Tolerance in Rice1[OPEN

    PubMed Central

    Yang, Chao; Ma, Biao; He, Si-Jie; Xiong, Qing; Duan, Kai-Xuan; Yin, Cui-Cui; Chen, Hui; Lu, Xiang; Chen, Shou-Yi; Zhang, Jin-Song

    2015-01-01

    Ethylene plays important roles in plant growth, development, and stress responses. The ethylene signaling pathway has been studied extensively, mainly in Arabidopsis (Arabidopsis thaliana). However, the molecular mechanism of ethylene signaling is largely unknown in rice (Oryza sativa). Previously, we have isolated a set of rice ethylene-response mutants. Here, we characterized the mutant maohuzi6 (mhz6). Through map-based cloning, we found that MHZ6 encodes ETHYLENE INSENSITIVE3-LIKE1 (OsEIL1), a rice homolog of ETHYLENE INSENSITIVE3 (EIN3), which is the master transcriptional regulator of ethylene signaling in Arabidopsis. Disruption of MHZ6/OsEIL1 caused ethylene insensitivity mainly in roots, whereas silencing of the closely related OsEIL2 led to ethylene insensitivity mainly in coleoptiles of etiolated seedlings. This organ-specific functional divergence is different from the functional features of EIN3 and EIL1, both of which mediate the incomplete ethylene responses of Arabidopsis etiolated seedlings. In Arabidopsis, EIN3 and EIL1 play positive roles in plant salt tolerance. In rice, however, lack of MHZ6/OsEIL1 or OsEIL2 functions improves salt tolerance, whereas the overexpressing lines exhibit salt hypersensitivity at the seedling stage, indicating that MHZ6/OsEIL1 and OsEIL2 negatively regulate salt tolerance in rice. Furthermore, this negative regulation by MHZ6/OsEIL1 and OsEIL2 in salt tolerance is likely attributable in part to the direct regulation of HIGH-AFFINITY K+ TRANSPORTER2;1 expression and Na+ uptake in roots. Additionally, MHZ6/OsEIL1 overexpression promotes grain size and thousand-grain weight. Together, our study provides insights for the functional diversification of MHZ6/OsEIL1 and OsEIL2 in ethylene response and finds a novel mode of ethylene-regulated salt stress response that could be helpful for engineering salt-tolerant crops. PMID:25995326

  2. Plasma Membrane Na+ Transport in a Salt-Tolerant Charophyte (Isotopic Fluxes, Electrophysiology, and Thermodynamics in Plants Adapted to Saltwater and Freshwater).

    PubMed

    Kiegle, E. A.; Bisson, M. A.

    1996-08-01

    In salt-tolerant Chara longifolia, enhanced Na+ efflux plays an important role in maintaining low cytoplasmic Na+. When it is cultured in fresh water (FW), C. longifolia has a higher Na+ efflux than the obligate FW Chara corallina, although pH dependence and inhibitor profiles are similar for both species (J. Whittington and M.A. Bisson [1994] J Exp Bot 45: 657-665). When it is cultured in saltwater, C. longifolia has a Na+ efflux of 264 [plus or minus] 14 nmol m-2 s-1 at pH 7, 13 times higher than FW-adapted cultures and 31 times higher than C. corallina. As in FW-adapted plants, efflux is highest at pH 5, but pH dependence is less steep and more linear in cells adapted to saltwater. In plants of both species from FW cultures, Na+ efflux is inhibited by Li+ at pH 5 but not at pH 7 or 9, whereas in the salt-adapted C. longifolia, Li+ inhibits Na+ efflux at pH 7 and 9 but not at pH 5. Amiloride inhibits Na+ efflux in salt-adapted cells but not in FW cells. We conclude that a new type of Na+ efflux system is induced in salt-adapted plants, although both systems have characteristics suggestive of a Na+/H+ antiport. In all cases, a 1:1 Na+/H+ antiport would have sufficient energy to maintain the cytoplasmic Na+ activities measured at pH 5 and 7 but not at pH 9, which suggests that another efflux system must be operating at pH 9. PMID:12226356

  3. A Glycine soja ABA-responsive receptor-like cytoplasmic kinase, GsRLCK, positively controls plant tolerance to salt and drought stresses.

    PubMed

    Sun, XiaoLi; Sun, Mingzhe; Luo, Xiao; Ding, XiaoDong; Ji, Wei; Cai, Hua; Bai, Xi; Liu, XiaoFei; Zhu, YanMing

    2013-06-01

    Receptor such as protein kinases are proposed to work as sensors to initiate signaling cascades in higher plants. However, little is known about the precise functions of receptor such as protein kinases in abiotic stress response in plants, especially in wild soybean. Here, we focused on characterization of the biological functions of a receptor-like cytoplasmic serine/threonine protein kinase gene, GsRLCK, which was previously identified as a putative salt-alkali stress-related gene from the transcriptome profiles of Glycine soja. Bioinformatic analysis showed that GsRLCK protein contained a conserved kinase catalytic domain and two transmembrane domains at the N-terminus, but no typical extracellular domain. Consistently, GsRLCK-eGFP fusion protein was observed on the plasma membrane, but eGFP alone was distributing throughout the cytoplasm in onion epidermal cells. Quantitative real-time PCR analysis revealed the induced expression of GsRLCK by ABA, salt, alkali, and drought stresses. However, the expression levels of GsRLCK seemed to be similar in different tissues, except soybean pod. Phenotypic assays demonstrated that GsRLCK overexpression decreased ABA sensitivity and altered expression levels of ABA-responsive genes. Furthermore, we also found that GsRLCK conferred increased tolerance to salt and drought stresses and increased expression levels of a handful of stress-responsive genes, when overexpressing in Arabidopsis. In a word, we gave exact evidence that GsRLCK was a novel receptor-like cytoplasmic protein kinase and played a crucial role in plant responses to ABA, salt, and drought stresses. PMID:23494614

  4. Coordinated Changes in Antioxidative Enzymes Protect the Photosynthetic Machinery from Salinity Induced Oxidative Damage and Confer Salt Tolerance in an Extreme Halophyte Salvadora persica L.

    PubMed

    Rangani, Jaykumar; Parida, Asish K; Panda, Ashok; Kumari, Asha

    2016-01-01

    Salinity-induced modulations in growth, photosynthetic pigments, relative water content (RWC), lipid peroxidation, photosynthesis, photosystem II efficiency, and changes in activity of various antioxidative enzymes were studied in the halophyte Salvadora persica treated with various levels of salinity (0, 250, 500, 750, and 1000 mM NaCl) to obtain an insight into the salt tolerance ability of this halophyte. Both fresh and dry biomass as well as leaf area (LA) declined at all levels of salinity whereas salinity caused an increase in leaf succulence. A gradual increase was observed in the Na(+) content of leaf with increasing salt concentration up to 750 mM NaCl, but at higher salt concentration (1000 mM NaCl), the Na(+) content surprisingly dropped down to the level of 250 mM NaCl. The chlorophyll and carotenoid contents of the leaf remained unaffected by salinity. The photosynthetic rate (PN), stomatal conductance (gs), the transpiration rate (E), quantum yield of PSII (ΦPSII), photochemical quenching (qP), and electron transport rate remained unchanged at low salinity (250 to 500 mM NaCl) whereas, significant reduction in these parameters were observed at high salinity (750 to 1000 mM NaCl). The RWC% and water use efficiency (WUE) of leaf remained unaffected by salinity. The salinity had no effect on maximum quantum efficiency of PS II (Fv/Fm) which indicates that PS II is not perturbed by salinity-induced oxidative damage. Analysis of the isoforms of antioxidative enzymes revealed that the leaves of S. persica have two isoforms each of Mn-SOD and Fe-SOD and one isoform of Cu-Zn SOD, three isoforms of POX, two isoforms of APX and one isoform of CAT. There was differential responses in activity and expression of different isoforms of various antioxidative enzymes. The malondialdehyde (MDA) content (a product of lipid peroxidation) of leaf remained unchanged in S. persica treated with various levels of salinity. Our results suggest that the absence of pigment

  5. Coordinated Changes in Antioxidative Enzymes Protect the Photosynthetic Machinery from Salinity Induced Oxidative Damage and Confer Salt Tolerance in an Extreme Halophyte Salvadora persica L.

    PubMed Central

    Rangani, Jaykumar; Parida, Asish K.; Panda, Ashok; Kumari, Asha

    2016-01-01

    Salinity-induced modulations in growth, photosynthetic pigments, relative water content (RWC), lipid peroxidation, photosynthesis, photosystem II efficiency, and changes in activity of various antioxidative enzymes were studied in the halophyte Salvadora persica treated with various levels of salinity (0, 250, 500, 750, and 1000 mM NaCl) to obtain an insight into the salt tolerance ability of this halophyte. Both fresh and dry biomass as well as leaf area (LA) declined at all levels of salinity whereas salinity caused an increase in leaf succulence. A gradual increase was observed in the Na+ content of leaf with increasing salt concentration up to 750 mM NaCl, but at higher salt concentration (1000 mM NaCl), the Na+ content surprisingly dropped down to the level of 250 mM NaCl. The chlorophyll and carotenoid contents of the leaf remained unaffected by salinity. The photosynthetic rate (PN), stomatal conductance (gs), the transpiration rate (E), quantum yield of PSII (ΦPSII), photochemical quenching (qP), and electron transport rate remained unchanged at low salinity (250 to 500 mM NaCl) whereas, significant reduction in these parameters were observed at high salinity (750 to 1000 mM NaCl). The RWC% and water use efficiency (WUE) of leaf remained unaffected by salinity. The salinity had no effect on maximum quantum efficiency of PS II (Fv/Fm) which indicates that PS II is not perturbed by salinity-induced oxidative damage. Analysis of the isoforms of antioxidative enzymes revealed that the leaves of S. persica have two isoforms each of Mn-SOD and Fe-SOD and one isoform of Cu-Zn SOD, three isoforms of POX, two isoforms of APX and one isoform of CAT. There was differential responses in activity and expression of different isoforms of various antioxidative enzymes. The malondialdehyde (MDA) content (a product of lipid peroxidation) of leaf remained unchanged in S. persica treated with various levels of salinity. Our results suggest that the absence of pigment

  6. Production of Yarrowia lipolytica Nha2 Na+/H+ antiporter improves the salt tolerance of Saccharomyces cerevisiae.

    PubMed

    Papousková, K; Sychrová, H

    2007-01-01

    Yarrowia lipolytica plasma-membrane Na+/H+ antiporter, encoded by the YlNHA2 gene, is a very efficient exporter of surplus sodium from the cytosol. Its heterologous expression in Saccharomyces cerevisiae wild-type laboratory strains increased their sodium tolerance more efficiently than the expression of ZrSod2-22 antiporter from the osmotolerant yeast Zygosaccharomvces rouxii. PMID:18450222

  7. Rhizobial and bradyrhizobial symbionts of mesquite from the Sonoran Desert: Salt tolerance, facultative halophily, and nitrate respiration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizobial symbionts from surface and phreatic absorbing root environments of a mature mesquite woodland in the Sonoran Desert of Southern California were tested for their ability to tolerate high salinity, and respire nitrate as mechanisms of free-living survival. Isolates were grown in yeast-extra...

  8. Phenological development stages variation versus mercury tolerance, accumulation, and allocation in salt marsh macrophytes Triglochin maritima and Scirpus maritimus prevalent in Ria de Aveiro coastal lagoon (Portugal).

    PubMed

    Anjum, Naser A; Ahmad, Iqbal; Válega, Mónica; Figueira, Etelvina; Duarte, Armando C; Pereira, Eduarda

    2013-06-01

    Efficient and sustainable management of rapidly mounting environmental issues has been the focus of current intensive research. The present study aimed to investigate the impact of plant phenological development stage variation on mercury (Hg) tolerance, accumulation, and allocation in two salt marsh macrophytes Triglochin maritima and Scirpus maritimus prevalent in historically Hg-contaminated Ria de Aveiro coastal lagoon (Portugal). Both plant samples and the sediments vegetated by monospecific stands of T. maritima and S. maritimus were collected from reference (R) and sites with moderate (M) and high (H) Hg contamination in Laranjo bay within Ria de Aveiro lagoon. Hg tolerance, uptake, and allocation in T. maritima and S. maritimus, physico-chemical traits (pH, redox potential, and organic matter content) and Hg concentrations in sediments vegetated by these species were impacted differentially by phenological development stages variation irrespective of the Hg contamination level. In T. maritima, Hg concentration increased with increase in Hg contamination gradient where root displayed significantly higher Hg followed by rhizome and leaf maximally at H. However, in S. maritimus, the highest Hg concentration was perceptible in rhizome followed by root maximally at M. Between the two studied plant species, S. maritimus displayed higher Hg tolerance index (depicted by higher plant dry mass allocated to reproductive stage) and higher available Hg at M (during all growth stages) and H (during senescent stage) when compared to T. maritimus. Both plant species proved to be Hg excluder (low root/rhizome-leaf Hg translocation). Additionally, T. maritima also acted as Hg stabilizer while, S. maritimus as Hg accumulator. It can be inferred from the study that (a) the plant phenological development stage variations significantly influenced plant Hg sensitivity by impacting sediment chemistry, plant growth (in terms of plant dry mass), Hg accumulation, and its subsequent

  9. Thermal inactivation kinetics of a three-strain composite of Salmonella Enteritidis and Oranienberg in commercially-acquired liquid whole egg and 10% salted liquid egg yolk

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction: Liquid egg pasteurization requirements are based on time/temperature combinations in the Code of Federal Regulations, Title 9, Ch. III, Sec. 590.570 from data acquired prior to 1970. These guidelines are being reevaluated in light of recent risk assessments, which take into account ch...

  10. Heterologous Expression of Two Jatropha Aquaporins Imparts Drought and Salt Tolerance and Improves Seed Viability in Transgenic Arabidopsis thaliana

    PubMed Central

    Khan, Kasim; Agarwal, Pallavi; Shanware, Arti; Sane, Vidhu Aniruddha

    2015-01-01

    Drought and high salinity are environmental conditions that cause adverse effects on the growth and productivity of crops. Aquaporins are small integral membrane proteins that belong to the family of the major intrinsic proteins (MIPs), with members in animals, plants and microbes, where they facilitate the transport of water and/or small neutral solutes thereby affecting water balance. In this study we characterized two aquaporin genes namely, plasma membrane intrinsic protein (PIP2;7) and tonoplast intrinsic protein TIP1;3 from Jatropha curcas that are localised to the plasma membrane and vacuole respectively. Transgenic Arabidopsis thaliana lines over-expressing JcPIP2;7 and JcTIP1;3 under a constitutive promoter show improved germination under high salt and mannitol compared to control seeds. These transgenic plants also show increased root length under abiotic stress conditions compared to wild type Col-0 plants. Transgenic lines exposed to drought conditions by withholding water for 20 days, were able to withstand water stress and attained normal growth after re-watering unlike control plants which could not survive. Transgenic lines also had better seed yield than control under salt stress. Importantly, seed viability of transgenic plants grown under high salt concentration was 35%-45% compared to less than 5% for control seeds obtained from plants growing under salt stress. The effect of JcPIP2;7 and JcTIP1;3 on improving germination and seed viability in drought and salinity make these important candidates for genetic manipulation of plants for growth in saline soils. PMID:26067295

  11. Heterologous Expression of Two Jatropha Aquaporins Imparts Drought and Salt Tolerance and Improves Seed Viability in Transgenic Arabidopsis thaliana.

    PubMed

    Khan, Kasim; Agarwal, Pallavi; Shanware, Arti; Sane, Vidhu Aniruddha

    2015-01-01

    Drought and high salinity are environmental conditions that cause adverse effects on the growth and productivity of crops. Aquaporins are small integral membrane proteins that belong to the family of the major intrinsic proteins (MIPs), with members in animals, plants and microbes, where they facilitate the transport of water and/or small neutral solutes thereby affecting water balance. In this study we characterized two aquaporin genes namely, plasma membrane intrinsic protein (PIP2;7) and tonoplast intrinsic protein TIP1;3 from Jatropha curcas that are localised to the plasma membrane and vacuole respectively. Transgenic Arabidopsis thaliana lines over-expressing JcPIP2;7 and JcTIP1;3 under a constitutive promoter show improved germination under high salt and mannitol compared to control seeds. These transgenic plants also show increased root length under abiotic stress conditions compared to wild type Col-0 plants. Transgenic lines exposed to drought conditions by withholding water for 20 days, were able to withstand water stress and attained normal growth after re-watering unlike control plants which could not survive. Transgenic lines also had better seed yield than control under salt stress. Importantly, seed viability of transgenic plants grown under high salt concentration was 35%-45% compared to less than 5% for control seeds obtained from plants growing under salt stress. The effect of JcPIP2;7 and JcTIP1;3 on improving germination and seed viability in drought and salinity make these important candidates for genetic manipulation of plants for growth in saline soils. PMID:26067295

  12. SlDEAD31, a Putative DEAD-Box RNA Helicase Gene, Regulates Salt and Drought Tolerance and Stress-Related Genes in Tomato.

    PubMed

    Zhu, Mingku; Chen, Guoping; Dong, Tingting; Wang, Lingling; Zhang, Jianling; Zhao, Zhiping; Hu, Zongli

    2015-01-01

    The DEAD-box RNA helicases are involved in almost every aspect of RNA metabolism, associated with diverse cellular functions including plant growth and development, and their importance in response to biotic and abiotic stresses is only beginning to emerge. However, none of DEAD-box genes was well characterized in tomato so far. In this study, we reported on the identification and characterization of two putative DEAD-box RNA helicase genes, SlDEAD30 and SlDEAD31 from tomato, which were classified into stress-related DEAD-box proteins by phylogenetic analysis. Expression analysis indicated that SlDEAD30 was highly expressed in roots and mature leaves, while SlDEAD31 was constantly expressed in various tissues. Furthermore, the expression of both genes was induced mainly in roots under NaCl stress, and SlDEAD31 mRNA was also increased by heat, cold, and dehydration. In stress assays, transgenic tomato plants overexpressing SlDEAD31 exhibited dramatically enhanced salt tolerance and slightly improved drought resistance, which were simultaneously demonstrated by significantly enhanced expression of multiple biotic and abiotic stress-related genes, higher survival rate, relative water content (RWC) and chlorophyll content, and lower water loss rate and malondialdehyde (MDA) production compared to wild-type plants. Collectively, these results provide a preliminary characterization of SlDEAD30 and SlDEAD31 genes in tomato, and suggest that stress-responsive SlDEAD31 is essential for salt and drought tolerance and stress-related gene regulation in plants. PMID:26241658

  13. Agrobacterium-mediated transformation of Eucalyptus globulus using explants with shoot apex with introduction of bacterial choline oxidase gene to enhance salt tolerance.

    PubMed

    Matsunaga, Etsuko; Nanto, Kazuya; Oishi, Masatoshi; Ebinuma, Hiroyasu; Morishita, Yoshihiko; Sakurai, Nozomu; Suzuki, Hideyuki; Shibata, Daisuke; Shimada, Teruhisa

    2012-01-01

    Eucalyptus globulus is one of the most economically important plantation hardwoods for paper making. However, its low transformation frequency has prevented genetic engineering of this species with useful genes. We found the hypocotyl section with a shoot apex has the highest regeneration ability among another hypocotyl sections, and have developed an efficient Agrobacterium-mediated transformation method using these materials. We then introduced a salt tolerance gene, namely a bacterial choline oxidase gene (codA) with a GUS reporter gene, into E. globulus. The highest frequency of transgenic shoot regeneration from hypocotyls with shoot apex was 7.4% and the average frequency in four experiments was 4.0%, 12-fold higher than that from hypocotyls without shoot apex. Using about 10,000 explants, over 250 regenerated buds were confirmed as transformants by GUS analysis. Southern blot analysis of 100 elongated shoots confirmed successful generation of stable transformants. Accumulation of glycinebetaine was investigated in 44 selected transgenic lines, which showed 1- to 12-fold higher glycinebetaine levels than non-transgenic controls. Rooting of 16 transgenic lines was successful using a photoautotrophic method under enrichment with 1,000 ppm CO(2). The transgenic whole plantlets were transplanted into potting soil and grown normally in a growth room. They showed salt tolerance to 300 mM NaCl. The points of our system are using explants with shoot apex as materials, inhibiting the elongation of the apex on the selection medium, and regenerating transgenic buds from the side opposite to the apex. This approach may also solve transformation problems in other important plants. PMID:22009051

  14. A rice stress-responsive NAC gene enhances tolerance of transgenic wheat to drought and salt stresses.

    PubMed

    Saad, Abu Sefyan I; Li, Xu; Li, He-Ping; Huang, Tao; Gao, Chun-Sheng; Guo, Mao-Wei; Cheng, Wei; Zhao, Guang-Yao; Liao, Yu-Cai

    2013-04-01

    Drought and salinity are the primary factors limiting wheat production worldwide. It has been shown that a rice stress-responsive transcription factor encoded by the rice NAC1 gene (SNAC1) plays an important role in drought stress tolerance. Therefore, we introduced the SNAC1 gene under the control of a maize ubiquitin promoter into an elite Chinese wheat variety Yangmai12. Plants expressing SNAC1 displayed significantly enhanced tolerance to drought and salinity in multiple generations, and contained higher levels of water and chlorophyll in their leaves, as compared to wild type. In addition, the fresh and dry weights of the roots of these plants were also increased, and the plants had increased sensitivities to abscisic acid (ABA), which inhibited root and shoot growth. Furthermore, quantitative real-time polymerase chain reactions revealed that the expressions of genes involved in abiotic stress/ABA signaling, such as wheat 1-phosphatidylinositol-3-phosphate-5-kinase, sucrose phosphate synthase, type 2C protein phosphatases and regulatory components of ABA receptor, were effectively regulated by the alien SNAC1 gene. These results indicated high and functional expression of the rice SNAC1 gene in wheat. And our study provided a promising approach to improve the tolerances of wheat cultivars to drought and salinity through genetic engineering. PMID:23415326

  15. A Novel Stress-Induced Sugarcane Gene Confers Tolerance to Drought, Salt and Oxidative Stress in Transgenic Tobacco Plants

    PubMed Central

    Begcy, Kevin; Mariano, Eduardo D.; Gentile, Agustina; Lembke, Carolina G.; Zingaretti, Sonia Marli; Souza, Glaucia M.; Menossi, Marcelo

    2012-01-01

    Background Drought is a major abiotic stress that affects crop productivity worldwide. Sugarcane can withstand periods of water scarcity during the final stage of culm maturation, during which sucrose accumulation occurs. Meanwhile, prolonged periods of drought can cause severe plant losses. Methodology/Principal Findings In a previous study, we evaluated the transcriptome of drought-stressed plants to better understand sugarcane responses to drought. Among the up-regulated genes was Scdr1 (sugarcane drought-responsive 1). The aim of the research reported here was to characterize this gene. Scdr1 encodes a putative protein containing 248 amino acids with a large number of proline (19%) and cysteine (13%) residues. Phylogenetic analysis showed that ScDR1is in a clade with homologs from other monocotyledonous plants, separate from those of dicotyledonous plants. The expression of Scdr1 in different varieties of sugarcane plants has not shown a clear association with drought tolerance. Conclusions/Significance The overexpression of Scdr1 in transgenic tobacco plants increased their tolerance to drought, salinity and oxidative stress, as demonstrated by increased photosynthesis, water content, biomass, germination rate, chlorophyll content and reduced accumulation of ROS. Physiological parameters, such as transpiration rate (E), net photosynthesis (A), stomatal conductance (gs) and internal leaf CO2 concentration, were less affected by abiotic stresses in transgenic Scdr1 plants compared with wild-type plants. Overall, our results indicated that Scdr1 conferred tolerance to multiple abiotic stresses, highlighting the potential of this gene for biotechnological applications. PMID:22984543

  16. Constitutive over-expression of rice ClpD1 protein enhances tolerance to salt and desiccation stresses in transgenic Arabidopsis plants.

    PubMed

    Mishra, Ratnesh Chandra; Richa; Grover, Anil

    2016-09-01

    Caseinolytic proteases (Clps) perform the important role of removing protein aggregates from cells, which can otherwise prove to be highly toxic. ClpD system is a two-component protease complex composed of a regulatory ATPase module ClpD and a proteolytic component ClpP. Under desiccation stress condition, rice ClpD1 (OsClpD1) gene encoding for the regulatory subunit, was represented by four variant transcripts differing mainly in the expanse of their N-terminal amino acids. These transcripts were expressed in a differential manner in response to salt, mannitol and polyethylene glycol stresses in rice. Purified OsClpD1.3 protein exhibited intrinsic chaperone activity, shown using citrate synthase as substrate. Arabidopsis (Col-0) plants over-expressing OsClpD1.3 open reading frame downstream to CaMV35S promoter (ClpD1.3 plants) showed higher tolerance to salt and desiccation stresses as compared to wild type plants. ClpD1.3 seedlings also showed enhanced growth during the early stages of seed germination under unstressed, control conditions. The free proline levels and starch breakdown activities were higher in the ClpD1.3 seedlings as compared to the wild type Arabidopsis seedlings. It thus emerges that increasing the potential of ClpD1 chaperoning activity may be of advantage in protection against abiotic stresses. PMID:27457985

  17. (E)-Propyl α-Cyano-4-Hydroxyl Cinnamylate: A High Sensitive and Salt Tolerant Matrix for Intact Protein Profiling by MALDI Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Wang, Sheng; Xiao, Zhaohui; Xiao, Chunsheng; Wang, Huixin; Wang, Bing; Li, Ying; Chen, Xuesi; Guo, Xinhua

    2016-04-01

    Low-abundance samples and salt interference are always of great challenges for the practical protein profiling by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). Herein, a series of carboxyl-esterified derivatives of α-cyano-4-hydroxycinnamic acid (CHCA) were synthesized and evaluated as matrices for MALDI-MS analysis of protein. Among them, (E)-propyl α-cyano-4-hydroxyl cinnamylate (CHCA-C3) was found to exhibit excellent assay performance for intact proteins by improving the detection sensitivity 10 folds compared with the traditional matrices [i.e., super2,5-dihydroxybenzoic acid (superDHB), sinapic acid (SA), and CHCA]. In addition, CHCA-C3 was shown to have high tolerance to salts, the ion signal of myoglobin was readily detected even in the presence of urea (8 M), NH4HCO3 (2 M), and KH2PO4 (500 mM), meanwhile sample washability was robust. These achievements were mainly attributed to improved ablation ability and increased hydrophobicity or affinity of CHCA-C3 to proteins in comparison with hydrophilic matrixes, leading to more efficient ionization of analyte. Furthermore, direct analysis of proteins from crude egg white demonstrated that CHCA-C3 was a highly efficient matrix for the analysis of low-abundance proteins in complex biological samples. These outstanding performances indicate the tremendous potential use of CHCA-C3 in protein profiling by MALDI-MS.

  18. A novel zinc-finger HIT protein with an additional PAPA-1-like region from Suaeda liaotungensis K. enhanced transgenic Arabidopsis drought and salt stresses tolerance.

    PubMed

    Li, Xiao-Lan; Hu, Yu-Xin; Yang, Xing; Yu, Xiao-Dong; Li, Qiu-Li

    2014-12-01

    Zinc-finger HIT belongs to the cross-brace zinc finger protein family and is involved in the regulation of plant defense and stress responses. In this study, we cloned a full-length zinc-finger HIT gene (1,377 bp) named SlPAPA1 using polymerase chain reaction from Suaeda liaotungensis K. and investigated its function by overexpression in transgenic Arabidopsis. SlPAPA1 contains a zinc-finger HIT domain and a Pim-1-associated protein-1 (PAP-1)-associated protein-1-like (PAPA-1-like) conserved region. Its expression in S. liaotungensis was induced by drought, high-salt, and cold (4 °C) stresses and by abscisic acid (ABA). Subcellular localization experiments in onion epidermal cells indicated that SlPAPA1 is localized in the nucleus. Yeast-one hybrid assays showed that SlPAPA1 functions as a transcriptional activator. SlPAPA1 transgenic Arabidopsis displayed a higher survival ratio and lower rate of water loss under drought stress; a higher germination ratio, higher survival ratio, and lower root inhibition rate under salt stress; and a lower germination ratio and root inhibition rate under ABA treatment, compared with wild-type Arabidopsis. These results suggested that SlPAPA1 functions as a stress-responsive zinc-finger HIT protein involved in the ABA-dependent signaling pathway and may have potential applications in transgenic breeding to enhance crops abiotic stress tolerances. PMID:25119646

  19. Production and characterization of a halo-, solvent-, thermo-tolerant alkaline lipase by Staphylococcus arlettae JPBW-1, isolated from rock salt mine.

    PubMed

    Chauhan, Mamta; Garlapati, Vijay Kumar

    2013-11-01

    Studies on lipase production and characterization were carried out with a bacterial strain Staphylococcus arlettae JPBW-1 isolated from rock salt mine, Darang, HP, India. Higher lipase activity has been obtained using 10 % inoculum with 5 % of soybean oil as carbon source utilizing a pH 8.0 in 3 h at 35 °C and 100 rpm through submerged fermentation. Partially purified S. arlettae lipase has been found to be active over a broad range of temperature (30-90 °C), pH (7.0-12.0) and NaCl concentration (0-20 %). It has shown extreme stability with solvents such as benzene, xylene, n-hexane, methanol, ethanol and toluene up to 30 % (v/v). The lipase activity has been found to be inhibited by metal ions of K(+), Co(2+) and Fe (2+) and stimulated by Mn(2+), Ca(2+) and Hg(2+). Lipase activity has been diminished with denaturants, but enhanced effect has been observed with surfactants, such as Tween 80, Tween 40 and chelator EDTA. The K m and V max values were found to be 7.05 mM and 2.67 mmol/min, respectively. Thus, the lipase from S. arlettae may have considerable potential for industrial application from the perspectives of its tolerance towards industrial extreme conditions of pH, temperature, salt and solvent. PMID:23955348

  20. Rapeseed calcineurin B-like protein CBL4, interacting with CBL-interacting protein kinase CIPK24, modulates salt tolerance in plants.

    PubMed

    Liu, Wu-Zhen; Deng, Min; Li, Liang; Yang, Bo; Li, Hongwei; Deng, Hanqing; Jiang, Yuan-Qing

    2015-11-20

    Calcium is a ubiquitous intracellular secondary messenger in eukaryotes. Upon stress challenge, cytosolic Ca(2+) fluctuation could be sensed and bound by calcineurin B-like proteins (CBLs), which further regulate a group of Ser/Thr protein kinases called CBL-interacting protein kinases (CIPKs) to relay the signal and induce cellular responses. Although the CBL-CIPK network has been demonstrated to play crucial roles in plant development and responses to various environmental stresses in Arabidopsis, little is known about their function in rapeseed. In the present study, we characterized CBL4 gene from rapeseed. We found that CBL4 is localized at the plasma membrane and it interacted with CIPK24 in both yeast two-hybrid and bimolecular fluorescence complementation (BiFC) assays. Unlike the orthologs in Arabidopsis, rapeseed CIPK24 did not interact with CBL10. Furthermore, expression of rapeseed CBL4 rescued the salt-sensitive phenotype of sos3-1 mutant and overexpression of rapeseed CBL4 in Arabidopsis showed enhanced tolerance of salt stress than wild-type. Overall, the results clarified the function of CBL4 in rapeseed. PMID:26462466

  1. A R2R3 type MYB transcription factor is involved in the cold regulation of CBF genes and in acquired freezing tolerance.

    PubMed

    Agarwal, Manu; Hao, Yujin; Kapoor, Avnish; Dong, Chun-Hai; Fujii, Hiroaki; Zheng, Xianwu; Zhu, Jian-Kang

    2006-12-01

    Cold temperatures trigger the expression of the CBF family of transcription factors, which in turn activate many downstream genes that confer freezing tolerance to plants. It has been shown previously that the cold regulation of CBF3 involves an upstream bHLH-type transcription factor, ICE1. ICE1 binds to the Myc recognition sequences in the CBF3 promoter. Apart from Myc recognition sequences, CBF promoters also have Myb recognition sequences. We report here that the Arabidopsis MYB15 is involved in cold-regulation of CBF genes and in the development of freezing tolerance. The MYB15 gene transcript is up-regulated by cold stress. The MYB15 protein interacts with ICE1 and binds to Myb recognition sequences in the promoters of CBF genes. Overexpression of MYB15 results in reduced expression of CBF genes whereas its loss-of-function leads to increased expression of CBF genes in the cold. The myb15 mutant plants show increased tolerance to freezing stress whereas its overexpression reduces freezing tolerance. Our results suggest that MYB15 is part of a complex network of transcription factors controlling the expression of CBFs and other genes in response to cold stress. PMID:17015446

  2. Overexpression of SpWRKY1 promotes resistance to Phytophthora nicotianae and tolerance to salt and drought stress in transgenic tobacco.

    PubMed

    Li, Jing-bin; Luan, Yu-shi; Liu, Zhen

    2015-11-01

    WRKY transcription factors are key regulatory components of plant responses to biotic and abiotic stresses. SpWRKY1, a pathogen-induced WRKY gene, was isolated from tomato (Solanum pimpinellifolium L3708) using in silico cloning and reverse transcriptase-polymerase chain reaction (RT-PCR) methods. SpWRKY1 expression was significantly induced following oomycete pathogen infection and treatment with salt, drought, salicylic acid (SA), methyl jasmonate (MeJA) and abscisic acid (ABA). Overexpression of SpWRKY1 in tobacco conferred greater resistance to Phytophthora nicotianae infection, as evidenced by lower malondialdehyde (MDA) content; relative electrolyte leakage (REL); higher chlorophyll content; and higher peroxidase (POD, EC 1.11.1.7), superoxide dismutase (SOD, EC 1.15.1.1) and phenylalanine ammonia-lyase (PAL, EC 4.3.1.24) activities. This resistance was also coupled with enhanced expression of SA- and JA-associated genes (NtPR1, NtPR2, NtPR4, NtPR5 and NtPDF1.2), as well as of various defense-related genes (NtPOD, NtSOD and NtPAL). In addition, transgenic tobacco plants also displayed an enhanced tolerance to salt and drought stresses, mainly demonstrated by the transgenic lines exhibiting lower accumulation of MDA content and higher POD (EC 1.11.1.7), SOD (EC 1.15.1.1) activities, chlorophyll content, photosynthetic rate and stomatal conductance, accompanied by enhanced expression of defense-related genes (NtPOD, NtSOD, NtLEA5, NtP5CS and NtNCED1) under salt and drought stresses. Overall, these findings suggest that SpWRKY1 acts as a positive regulator involved in tobacco defense responses to biotic and abiotic stresses. PMID:25496091

  3. Role of Organic Carbonyl Moiety and 3-Aminopropyltrimethoxysilane on the Synthesis of Gold Nanoparticles Specific to pH- and Salt-Tolerance.

    PubMed

    Pandey, P C; Pandey, Gunjan; Haider, Jamal; Pandey, Govind

    2016-06-01

    The synthesis of gold nanoparticles (AuNPs) having better dispersibility and catalytic ability than the conventional AuNPs is the challenging task. The fact that aldehydes and ketones results in the formation of catalytic hybrid material with amino functionalized silanes directed the use of carbonyl functional group (aldehydes and ketones) specifically formaldehyde, acetaldehyde, acetone and t-butyl methyl ketone alongwith 3-aminopropyltrimethoxysilane (3-APTMS) to meet such requirement. Accordingly, a comparative study on the synthesis of 3-APTMS and organic reducing agent mediated synthesis of AuNPs are reported herein. The findings reveal that 3-APTMS capped gold ions are converted into AuNPs with precise control of pH- and salt- sensitivity. The major findings reveal the following: (1) 3-APTMS being amphiphilic, dispersibility of as prepared AuNPs largely depends on the organic reducing agents. (2) An increase in the hydrocarbon content of the reducing agent facilitate the dispersibility of AuNPs in organic solvent whereas decrease of the same increases the dispersibility in water, (3) AuNPs made through aldehydic reducing agents (formaldehyde and acetaldehyde) have relatively better salt and pH tolerance as compared to ketonic reducing agents (acetone, t-butyl methyl ketone), and (4) an increase in 3-APTMS concentrations imparts better salt- and pH- resistant property to AuNPs irrespective of organic reducing agents. A typical example on the role of AuNPs in homogeneous catalysis during potassium ferricyanide mediated oxidation of ascorbic acid is also reported. PMID:27427685

  4. Draft Genome Sequence of Frankia sp. Strain BMG5.23, a Salt-Tolerant Nitrogen-Fixing Actinobacterium Isolated from the Root Nodules of Casuarina glauca Grown in Tunisia

    PubMed Central

    Ghodhbane-Gtari, Faten; Hurst, Sheldon G.; Oshone, Rediet; Morris, Krystalynne; Abebe-Akele, Feseha; Thomas, W. Kelley; Ktari, Amir; Salem, Karima; Gtari, Maher

    2014-01-01

    Nitrogen-fixing actinobacteria of the genus Frankia are symbionts of woody dicotyledonous plants termed actinorhizal plants. We report here a 5.27-Mbp draft genome sequence for Frankia sp. strain BMG5.23, a salt-tolerant nitrogen-fixing actinobacterium isolated from root nodules of Casuarina glauca collected in Tunisia. PMID:24874687

  5. Transgenic evaluation of activated mutant alleles of SOS2 reveals a critical requirement for its kinase activity and C-terminal regulatory domain for salt tolerance in Arabidopsis thaliana

    DOEpatents

    Zhu, Jian-Kang; Quintero-Toscano, Francisco Javier; Pardo-Prieto, Jose Manuel; Qiu, Quansheng; Schumaker, Karen Sue; Ohta, Masaru; Zhang, Changqing; Guo, Yan

    2007-09-04

    The present invention provides a method of increasing salt tolerance in a plant by overexpressing a gene encoding a mutant SOS2 protein in at least one cell type in the plant. The present invention also provides for transgenic plants expressing the mutant SOS2 proteins.

  6. Draft Genome Sequence of Frankia sp. Strain BMG5.23, a Salt-Tolerant Nitrogen-Fixing Actinobacterium Isolated from the Root Nodules of Casuarina glauca Grown in Tunisia.

    PubMed

    Ghodhbane-Gtari, Faten; Hurst, Sheldon G; Oshone, Rediet; Morris, Krystalynne; Abebe-Akele, Feseha; Thomas, W Kelley; Ktari, Amir; Salem, Karima; Gtari, Maher; Tisa, Louis S

    2014-01-01

    Nitrogen-fixing actinobacteria of the genus Frankia are symbionts of woody dicotyledonous plants termed actinorhizal plants. We report here a 5.27-Mbp draft genome sequence for Frankia sp. strain BMG5.23, a salt-tolerant nitrogen-fixing actinobacterium isolated from root nodules of Casuarina glauca collected in Tunisia. PMID:24874687

  7. Enhanced salt stress tolerance of rice plants expressing a vacuolar H+-ATPase subunit c1 (SaVHAc1) gene from the halophyte grass Spartina alterniflora Löisel

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The physiological role of a vacuolar ATPase subunit c1 (SaVHAc1) from a halophyte grass Spartina alterniflora was studied through its expression in rice. The SaVHAc1– expressing plants showed enhanced tolerance to salt stress than the wild-type plants, mainly through adjustments in early stage and p...

  8. Ectopic Overexpression of SsCBF1, a CRT/DRE-Binding Factor from the Nightshade Plant Solanum lycopersicoides, Confers Freezing and Salt Tolerance in Transgenic Arabidopsis

    PubMed Central

    Zhang, Lili; Li, Zhenjun; Li, Jingfu; Wang, Aoxue

    2013-01-01

    The C-repeat (CRT)/dehydration-responsive element (DRE) binding factor (CBF/DREB1) transcription factors play a key role in cold response. However, the detailed roles of many plant CBFs are far from fully understood. A CBF gene (SsCBF1) was isolated from the cold-hardy plant Solanum lycopersicoides. A subcellular localization study using GFP fusion protein indicated that SsCBF1 is localized in the nucleus. We delimited the SsCBF1 transcriptional activation domain to the C-terminal segment comprising amino acid residues 193–228 (SsCBF1193–228). The expression of SsCBF1 could be dramatically induced by cold, drought and high salinity. Transactivation assays in tobacco leaves revealed that SsCBF1 could specifically bind to the CRT cis-elements in vivo to activate the expression of downstream reporter genes. The ectopic overexpression of SsCBF1 conferred increased freezing and high-salinity tolerance and late flowering phenotype to transgenic Arabidopsis. RNA-sequencing data exhibited that a set of cold and salt stress responsive genes were up-regulated in transgenic Arabidopsis. Our results suggest that SsCBF1 behaves as a typical CBF to contribute to plant freezing tolerance. Increased resistance to high-salinity and late flowering phenotype derived from SsCBF1 OE lines lend more credence to the hypothesis that plant CBFs participate in diverse physiological and biochemical processes related to adverse conditions. PMID:23755095

  9. Biochemical characterization and structural analysis of a new cold-active and salt-tolerant esterase from the marine bacterium Thalassospira sp.

    PubMed

    De Santi, Concetta; Leiros, Hanna-Kirsti S; Di Scala, Alessia; de Pascale, Donatella; Altermark, Bjørn; Willassen, Nils-Peder

    2016-05-01

    A gene encoding an esterase, ThaEst2349, was identified in the marine psychrophilic bacterium Thalassospira sp. GB04J01. The gene was cloned and overexpressed in E. coli as a His-tagged fusion protein. The recombinant enzyme showed optimal activity at 45 °C and the thermal stability displayed a retention of 75 % relative activity at 40 °C after 2 h. The optimal pH was 8.5 but the enzyme kept more than 75 % of its maximal activity between pH 8.0 and 9.5. ThaEst2349 also showed remarkable tolerance towards high concentrations of salt and it was active against short-chain p-nitrophenyl esters, displaying optimal activity with the acetate. The enzyme was tested for tolerance of organic solvents and the results are suggesting that it could function as an interesting candidate for biotechnological applications. The crystal structure of ThaEst2349 was determined to 1.69 Å revealing an asymmetric unit containing two chains, which also is the biological unit. The structure has a characteristic cap domain and a catalytic triad comprising Ser158, His285 and Asp255. To explain the cold-active nature of the enzyme, we compared it against thermophilic counterparts. Our hypothesis is that a high methionine content, less hydrogen bonds and less ion pairs render the enzyme more flexible at low temperatures. PMID:27016194

  10. 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

  11. Cloning and characterization of a maize bZIP transcription factor, ZmbZIP72, confers drought and salt tolerance in transgenic Arabidopsis.

    PubMed

    Ying, Sheng; Zhang, Deng-Feng; Fu, Jing; Shi, Yun-Su; Song, Yan-Chun; Wang, Tian-Yu; Li, Yu

    2012-02-01

    In plants, the bZIP (basic leucine zipper) transcription factors regulate diverse functions, including processes such as plant development and stress response. However, few have been functionally characterized in maize (Zea mays). In this study, we cloned ZmbZIP72, a bZIP transcription factor gene from maize, which had only one copy in the maize genome and harbored three introns. Analysis of the amino acid sequence of ZmbZIP72 revealed a highly conserved bZIP DNA-binding domain in its C-terminal region, and four conserved sequences distributed in N- or C-terminal region. The ZmbZIP72 gene expressed differentially in various organs of maize plants and was induced by abscisic acid, high salinity, and drought treatment in seedlings. Subcellular localization analysis in onion epidermal cells indicated that ZmbZIP72 was a nuclear protein. Transactivation assay in yeast demonstrated that ZmbZIP72 functioned as a transcriptional activator and its N terminus (amino acids 23-63) was necessary for the transactivation activity. Heterologous overexpression of ZmbZIP72 improved drought and partial salt tolerance of transgenic Arabidopsis plants, as determined by physiological analyses of leaf water loss, electrolyte leakage, proline content, and survival rate under stress. In addition, the seeds of ZmbZIP72-overexpressing transgenic plants were hypersensitive to ABA and osmotic stress. Moreover, overexpression of ZmbZIP72 enhanced the expression of ABA-inducible genes such as RD29B, RAB18, and HIS1-3. These results suggest that the ZmbZIP72 protein functions as an ABA-dependent transcription factor in positive modulation of abiotic stress tolerance and may be a candidate gene with potential application in molecular breeding to enhance stress tolerance in crops. PMID:21866346

  12. Cloning, Characterization and Expression Pattern Analysis of a Cytosolic Copper/Zinc Superoxide Dismutase (SaCSD1) in a Highly Salt Tolerant Mangrove (Sonneratia alba)

    PubMed Central

    Yang, Enze; Yi, Shanze; Bai, Fang; Niu, Dewei; Zhong, Junjie; Wu, Qiuhong; Chen, Shufang; Zhou, Renchao; Wang, Feng

    2015-01-01

    Mangroves are critical marine resources for their remarkable ability to tolerate seawater. Antioxidant enzymes play an especially significant role in eliminating reactive oxygen species and conferring abiotic stress tolerance. In this study, a cytosolic copper/zinc superoxide dismutase (SaCSD1) cDNA of Sonneratia alba, a mangrove species with high salt tolerance, was successfully cloned and then expressed in Escherichia coli Rosetta-gami (designated as SaCSD1). SaCSD1 comprised a complete open reading frame (ORF) of 459 bp which encoded a protein of 152 amino acids. Its mature protein is predicted to be 15.32 kDa and the deduced isoelectric point is 5.78. SaCSD1 has high sequence similarity (85%–90%) with the superoxide dismutase (CSD) of some other plant species. SaCSD1 was expressed with 30.6% yield regarding total protein content after being introduced into the pET-15b (Sma I) vector for expression in Rosetta-gami and being induced with IPTG. After affinity chromatography on Ni-NTA, recombinant SaCSD1 was obtained with 3.2-fold purification and a specific activity of 2200 U/mg. SaCSD1 showed good activity as well as stability in the ranges of pH between 3 and 7 and temperature between 25 and 55 °C. The activity of recombinant SaCSD1 was stable in 0.25 M NaCl, Dimethyl Sulphoxide (DMSO), glycerol, and chloroform, and was reduced to a great extent in β-mercaptoethanol, sodium dodecyl sulfate (SDS), H2O2, and phenol. Moreover, the SaCSD1 protein was very susceptive to pepsin digestion. Real-time Quantitative Polymerase Chain Reaction (PCR) assay demonstrated that SaCSD1 was expressed in leaf, stem, flower, and fruit organs, with the highest expression in fruits. Under 0.25 M and 0.5 M salt stress, the expression of SaCSD1 was down-regulated in roots, but up-regulated in leaves. PMID:26703583

  13. Cloning, Characterization and Expression Pattern Analysis of a Cytosolic Copper/Zinc Superoxide Dismutase (SaCSD1) in a Highly Salt Tolerant Mangrove (Sonneratia alba).

    PubMed

    Yang, Enze; Yi, Shanze; Bai, Fang; Niu, Dewei; Zhong, Junjie; Wu, Qiuhong; Chen, Shufang; Zhou, Renchao; Wang, Feng

    2016-01-01

    Mangroves are critical marine resources for their remarkable ability to tolerate seawater. Antioxidant enzymes play an especially significant role in eliminating reactive oxygen species and conferring abiotic stress tolerance. In this study, a cytosolic copper/zinc superoxide dismutase (SaCSD1) cDNA of Sonneratia alba, a mangrove species with high salt tolerance, was successfully cloned and then expressed in Escherichia coli Rosetta-gami (designated as SaCSD1). SaCSD1 comprised a complete open reading frame (ORF) of 459 bp which encoded a protein of 152 amino acids. Its mature protein is predicted to be 15.32 kDa and the deduced isoelectric point is 5.78. SaCSD1 has high sequence similarity (85%-90%) with the superoxide dismutase (CSD) of some other plant species. SaCSD1 was expressed with 30.6% yield regarding total protein content after being introduced into the pET-15b (Sma I) vector for expression in Rosetta-gami and being induced with IPTG. After affinity chromatography on Ni-NTA, recombinant SaCSD1 was obtained with 3.2-fold purification and a specific activity of 2200 U/mg. SaCSD1 showed good activity as well as stability in the ranges of pH between 3 and 7 and temperature between 25 and 55 °C. The activity of recombinant SaCSD1 was stable in 0.25 M NaCl, Dimethyl Sulphoxide (DMSO), glycerol, and chloroform, and was reduced to a great extent in β-mercaptoethanol, sodium dodecyl sulfate (SDS), H₂O2, and phenol. Moreover, the SaCSD1 protein was very susceptive to pepsin digestion. Real-time Quantitative Polymerase Chain Reaction (PCR) assay demonstrated that SaCSD1 was expressed in leaf, stem, flower, and fruit organs, with the highest expression in fruits. Under 0.25 M and 0.5 M salt stress, the expression of SaCSD1 was down-regulated in roots, but up-regulated in leaves. PMID:26703583

  14. Identification and analysis of the salt tolerant property of AHL lactonase (AiiATSAWB ) of Bacillus species.

    PubMed

    Easwaran, Nalini; Karthikeyan, Sivashanmugam; Sridharan, Balasundaram; Gothandam, Kodiveri Muthukaliannan

    2015-05-01

    Bacterial biofilms communicate by a process called Quorum Sensing. Gram negative bacterial pathogens specifically talk through the production, detection, and response to the signal or autoinducer called Acyl Homoserine Lactones. Bacterial lactonases are important AHL hydrolysing or quorum quenching enzymes. The present study deals with ten endospore forming gram positive isolates of the saltern soil. Preliminary screening for Quorum Quenching activity with the QS Inhibition indicator strain Chromobacterium violaceum ATCC 12472, showed positive activity in four isolates namely TS2, TS16, TSAWB, and TS53B. AHL lactonase (AiiA) specific primers amplified Acyl Homoserine Lactone lactonase gene in the TSAWB genome alone. Phylogenetic relationship of the identified AiiATSAWB confirmed its evolutionary relationship with bacterial AiiA like AHL lactonase of the metallo-beta-lactamase super family. Our in vitro AHL hydrolysis assay under wide percentage (0-5) of salt solutions with TSAWB isolate and also its intracellular soluble protein fraction showed halotolerant AHL hydrolysis ability of the AiiATSAWB enzyme. In silico determination of putative tertiary structure, the ESBRI derived conserved salt bridges, aminoacid residue characterization with high mole percent of acidic and hydrophobic residues reaffirmed the halotolerant ability of the enzyme. So we propound the future use of purified AiiATSAWB , as hypertonic suspension for inhalation to substitute the action of inactivated host's paraoxonase in treating Pseudomonas aeruginosa infection in cystic fibrosis patients. PMID:25041996

  15. Enhanced salt stress tolerance in transgenic potato plants expressing IbMYB1, a sweet potato transcription factor.

    PubMed

    Cheng, Yu-Jie; Kim, Myoung-Duck; Deng, Xi-Ping; Kwak, Sang-Soo; Chen, Wei

    2013-12-01

    IbMYB1, a transcription factor (TF) for R2R3-type MYB TFs, is a key regulator of anthocyanin biosynthesis during storage of sweet potatoes. Anthocyanins provide important antioxidants of nutritional value to humans, and also protect plants from oxidative stress. This study aimed to increase transgenic potatoes' (Solanum tuberosum cv. LongShu No.3) tolerance to environmental stress and enhance their nutritional value. Transgenic potato plants expressing IbMYB1 genes under the control of an oxidative stress-inducible peroxidase (SWPA2) promoter (referred to as SM plants) were successfully generated through Agrobacterium-mediated transformation. Two representative transgenic SM5 and SM12 lines were evaluated for enhanced tolerance to salinity, UV-B rays, and drought conditions. Following treatment of 100 mM NaCl, seedlings of SM5 and SM12 lines showed less root damage and more shoot growth than control lines expressing only an empty vector. Transgenic potato plants in pots treated with 400 mM NaCl showed high amounts of secondary metabolites, including phenols, anthocyanins, and flavonoids, compared with control plants. After treatment of 400 mM NaCl, transgenic potato plants also showed high DDPH radical scavenging activity and high PS II photochemical efficiency compared with the control line. Furthermore, following treatment of NaCl, UV-B, and drought stress, the expression levels of IbMYB1 and several structural genes in the flavonoid biosynthesis such as CHS, DFR, and ANS in transgenic plants were found to be correlated with plant phenotype. The results suggest that enhanced IbMYB1 expression affects secondary metabolism, which leads to improved tolerance ability in transgenic potatoes. PMID:24378636

  16. [Evaluation of Salt Tolerance of Transgenic Tobacco Plants Bearing with P5CS1 Gene of Arabidopsis thaliana].

    PubMed

    Ibragimova, S M; Trifonova, E A; Filipenko, E A; Shymny, V K

    2015-12-01

    Arabidopsis thaliana delta1-pyrroline-5-carhoxylate synthase 1 gene (P5CS1) cDNA was cloned under the control of the potent constitutive 35S RNA promoter of the cauliflower mosaic virus and transferred into genome of tobacco cv. Petit Havana SR-1 (Nicotiana tabacum L.) plants. It is shown that the constitutive level of proline in the transgenic plants T0 exceeds that of the SR1 reference line by 1.5 to 4 times. Under conditions of salt stress (200, 300 mM NaCl) T1-generation transgenic plants in early stages of development formed a large biomass, developed more quickly, and had a higher rate of root growth compared to the control, which confirms the involvement of the P5CS1 gene in molecular mechanisms of stress resistance in plants. PMID:27055296

  17. Sodium induces simultaneous changes in cytosolic calcium and pH in salt-tolerant quince protoplasts.

    PubMed

    D'Onofrio, Cladio; Lindberg, Sylvia

    2009-11-01

    Previous experiments with salt-resistant quince BA29 (Cydonia oblonga cv. Mill.) have shown that this cultivar takes up sodium transiently into the cytosol of shoot protoplasts only in the absence of calcium chloride, or at <1mM calcium chloride. Addition of NaCl > or =100mM to single protoplasts from in vitro-cultivated quince in the presence of 1.0mM calcium induced instant changes in the cytosolic concentrations of calcium and protons. These changes were investigated by use of tetra [acetoxymethyl] esters of the fluorescent stilbene chromophores Fura 2 and bis-carboxyethyl-carboxyfluorescein (BCECF), respectively. The cytosolic Ca(2+) dynamics in the protoplasts were dependent on the concentration of NaCl added. The changes in calcium differed in amplitude and final concentration and were correlated in time mainly with changes in pH. Addition of 100-400mM NaCl to the protoplasts caused an oscillating increase in the cytosolic level of calcium, and then a decrease. Addition of mannitol, of equiosmolar concentration to NaCl, did not increase the cytosolic calcium concentration. Moreover, there was no increase in cytosolic calcium when NaCl was added in the presence of calcium binding ethylene glycol-bis(beta-aminoethylether)-N,N,N',N'-tetra acetic acid (EGTA), or lantan or verapamil, two inhibitors of plasma membrane calcium channels. Therefore, we conclude that, in salt-resistant quince, sodium induces an influx of calcium into the cytosol by plasma membrane calcium channels, and a simultaneous increase in cytosolic pH. Because these changes were obtained in the presence of 1mM calcium in the medium, they were not due to sodium uptake into the cytosol. PMID:19556023

  18. The potential of a salt-tolerant plant (Distichlis spicata cv. NyPa Forage) to treat effluent from inland saline aquaculture and provide livestock feed on salt-affected farmland.

    PubMed

    Lymbery, Alan J; Kay, Gavin D; Doupé, Robert G; Partridge, Gavin J; Norman, Hayley C

    2013-02-15

    Dryland salinity is a major problem affecting food production from agricultural land in Australia and throughout the world. Although there is much interest in using saline groundwater to grow marine fish on salt-affected farmland, the disposal of nutrient enriched, saline aquaculture effluent is a major environmental problem. We investigated the potential of the salt-tolerant NyPa Forage plant (Distichlis spicata L. Greene var. yensen-4a) to trap nutrients from saline aquaculture effluent and subsequently to provide a fodder crop for livestock. Sub-surface flow wetlands containing NyPa Forage were constructed and their efficacy in removing total nitrogen, ammonia, nitrite/nitrate, total phosphorus and orthophosphate was monitored under different levels of nutrients and salinity. The wetlands removed 60-90% of total nitrogen loads and at least 85% of ammonia, nitrite/nitrate, total phosphorus and orthophosphate loads, with greater efficiency at high nutrient and low salinity levels. The above-ground yield, sodium, crude protein (CP) and in vitro dry matter digestibility (DMD) of NyPa Forage plants were measured after fertilisation with different nutrient levels and cropping at different frequencies. Yield of plants increased with increased nutrient, while nutritive value was greater when nutrients were applied but did not differ among nutrient levels. Yield was not affected by cropping frequency, but nutritive value was greatest when plants were cropped at intervals of 21 or 42 days. At optimum nutrient addition and cropping levels, the plants had a mean CP content of 16.7% and an in vitro DMD of 67.6%, equivalent to an energy value of 9.5 MJ kg(-1). Assuming an equivalent fibre content and voluntary food intake as grass hay, and no accumulation of other toxic minerals, these nutritive values would be sufficient for maintenance or moderate liveweight gains in dry adult sheep or cattle. PMID:23333515

  19. Overexpression of Crocus carotenoid cleavage dioxygenase, CsCCD4b, in Arabidopsis imparts tolerance to dehydration, salt and oxidative stresses by modulating ROS machinery.

    PubMed

    Baba, Shoib Ahmad; Jain, Deepti; Abbas, Nazia; Ashraf, Nasheeman

    2015-09-15

    Apocarotenoids modulate vital physiological and developmental processes in plants. These molecules are formed by the cleavage of carotenoids, a reaction catalyzed by a family of enzymes called carotenoid cleavage dioxygenases (CCDs). Apocarotenoids like β-ionone and β-cyclocitral have been reported to act as stress signal molecules during high light stress in many plant species. In Crocus sativus, these two apocarotenoids are formed by enzymatic cleavage of β-carotene at 9, 10 and 7, 8 bonds by CsCCD4 enzymes. In the present study three isoforms of CsCCD4 were subjected to molecular modeling and docking analysis to determine their substrate specificity and all the three isoforms displayed high substrate specificity for β-carotene. Further, expression of these three CsCCD4 isoforms investigated in response to various stresses revealed that CsCCD4a and CsCCD4b exhibit enhanced expression in response to dehydration, salt and methylviologen, providing a clue towards their role in mediating plant defense response. This was confirmed by overexpressing CsCCD4b in Arabidopsis. The transgenic plants developed longer roots and possessed higher number of lateral roots. Further, overexpression of CsCCD4b imparted enhanced tolerance to salt, dehydration and oxidative stresses as was evidenced by higher survival rate, increased relative root length and biomass in transgenic plants as compared to wild type. Transgenic plants also displayed higher activity and expression of reactive oxygen species (ROS) metabolizing enzymes. This indicates that β-ionone and β-cyclocitral which are enzymatic products of CsCCD4b may act as stress signals and mediate reprogramming of stress responsive genes which ultimately leads to plant defense. PMID:26595090

  20. High-throughput screening for a moderately halophilic phenol-degrading strain and its salt tolerance response.

    PubMed

    Lu, Zhi-Yan; Guo, Xiao-Jue; Li, Hui; Huang, Zhong-Zi; Lin, Kuang-Fei; Liu, Yong-Di

    2015-01-01

    A high-throughput screening system for moderately halophilic phenol-degrading bacteria from various habitats was developed to replace the conventional strain screening owing to its high efficiency. Bacterial enrichments were cultivated in 48 deep well microplates instead of shake flasks or tubes. Measurement of phenol concentrations was performed in 96-well microplates instead of using the conventional spectrophotometric method or high-performance liquid chromatography (HPLC). The high-throughput screening system was used to cultivate forty-three bacterial enrichments and gained a halophilic bacterial community E3 with the best phenol-degrading capability. Halomonas sp. strain 4-5 was isolated from the E3 community. Strain 4-5 was able to degrade more than 94% of the phenol (500 mg · L(-1) starting concentration) over a range of 3%-10% NaCl. Additionally, the strain accumulated the compatible solute, ectoine, with increasing salt concentrations. PCR detection of the functional genes suggested that the largest subunit of multicomponent phenol hydroxylase (LmPH) and catechol 1,2-dioxygenase (C12O) were active in the phenol degradation process. PMID:26020478

  1. Thermo- and salt-tolerant chitosan cross-linked γ-glutamyl transpeptidase from Bacillus licheniformis ER15.

    PubMed

    Bindal, Shruti; Gupta, Rani

    2016-10-01

    Gamma-glutamyl transpeptidase enzyme, from Bacillus licheniformis ER15 (BLGGT), was produced extracellularly using a complex medium with high enzyme titers. Enzyme was concentrated and purified using ultra-filtration and ion exchange chromatography, respectively, with a purification fold of 4.6 and 50.11% yield. Enzyme was covalently immobilized onto chitosan microspheres (CMS). Immobilization was standardized with respect to pH, enzyme load and time. Immobilization efficiency of 11.9U/mg dry weight of microsphere was obtained in Tris-HCl buffer (pH 9.0) at 18°C in 4h. Immobilized enzyme (CMS-GGT) exhibited improved thermal stability (t1/2 of 70.7min at 60°C), activity in a broader pH range and improved salt stability in 18% (3M) sodium chloride solution as compared to free enzyme. Both free and immobilized enzymes specifically converted glutamine to glutamic acid in a mixture of amino acids. CMS-GGT had a better shelf life and high recyclability retaining 90% catalytic efficiency upto 10 reaction cycles. For long-term storage, CMS-GGT can be disinfected using either sodium azide or sodium hypochlorite solution without affecting enzyme activity. Thus, the present study provides an easy and efficient method for GGT enzyme immobilization that results in an improved and robust enzyme preparation. PMID:27259644

  2. Endogenous siRNAs derived from a pair of natural cis-antisense transcripts regulate salt tolerance in Arabidopsis.

    PubMed

    Borsani, Omar; Zhu, Jianhua; Verslues, Paul E; Sunkar, Ramanjulu; Zhu, Jian-Kang

    2005-12-29

    In higher eukaryotes, miRNAs and siRNAs guide translational inhibition, mRNA cleavage, or chromatin regulation. We found that the antisense overlapping gene pair of Delta(1)-pyrroline-5-carboxylate dehydrogenase (P5CDH), a stress-related gene, and SRO5, a gene of unknown function, generates two types of siRNAs. When both transcripts are present, a 24-nt siRNA is formed by a biogenesis pathway dependent on DCL2, RDR6, SGS3, and NRPD1A. Initial cleavage of the P5CDH transcript guided by the 24-nt siRNA establishes a phase for the subsequent generation of 21-nt siRNAs by DCL1 and further cleavage of P5CDH transcripts. The expression of SRO5 is induced by salt, and this induction is required to initiate siRNA formation. Our data suggest that the P5CDH and SRO5 proteins are also functionally related, and that the P5CDH-SRO5 gene pair defines a mode of siRNA function and biogenesis that may be applied to other natural cis-antisense gene pairs in eukaryotic genomes. PMID:16377568

  3. Characterization of a salt-tolerant family 42 beta-galactosidase from a psychrophilic antarctic Planococcus isolate.

    PubMed

    Sheridan, P P; Brenchley, J E

    2000-06-01

    We isolated a gram-positive, halotolerant psychrophile from a hypersaline pond located on the McMurdo Ice Shelf in Antarctica. A phylogenetic analysis of the 16S rRNA gene sequence of this organism showed that it is a member of the genus Planococcus. This assignment is consistent with the morphology and physiological characteristics of the organism. A gene encoding a beta-galactosidase in this isolate was cloned in an Escherichia coli host. Sequence analysis of this gene placed it in glycosidase family 42 most closely related to an enzyme from Bacillus circulans. Even though an increasing number of family 42 glycosidase sequences are appearing in databases, little information about the biochemical features of these enzymes is available. Therefore, we purified and characterized this enzyme. The purified enzyme did not appear to have any metal requirement, had an optimum pH of 6.5 and an optimum temperature of activity at 42 degrees C, and was irreversibly inactivated within 10 min when it was incubated at 55 degrees C. The enzyme had an apparent K(m) of 4.9 micromol of o-nitrophenyl-beta-D-galactopyranoside, and the V(max) was 467 micromol of o-nitrophenol produced/min/mg of protein at 39 degrees C. Of special interest was the finding that the enzyme remained active at high salt concentrations, which makes it a possible reporter enzyme for halotolerant and halophilic organisms. PMID:10831422

  4. Constitutive Expression of a miR319 Gene Alters Plant Development and Enhances Salt and Drought Tolerance in Transgenic Creeping Bentgrass1[W][OA

    PubMed Central

    Zhou, Man; Li, Dayong; Li, Zhigang; Hu, Qian; Yang, Chunhua; Zhu, Lihuang; Luo, Hong

    2013-01-01

    MicroRNA319 (miR319) is one of the first characterized and conserved microRNA families in plants and has been demonstrated to target TCP (for TEOSINTE BRANCHED/CYCLOIDEA/PROLIFERATING CELL FACTORS [PCF]) genes encoding plant-specific transcription factors. MiR319 expression is regulated by environmental stimuli, suggesting its involvement in plant stress response, although experimental evidence is lacking and the underlying mechanism remains elusive. This study investigates the role that miR319 plays in the plant response to abiotic stress using transgenic creeping bentgrass (Agrostis stolonifera) overexpressing a rice (Oryza sativa) miR319 gene, Osa-miR319a. We found that transgenic plants overexpressing Osa-miR319a displayed morphological changes and exhibited enhanced drought and salt tolerance associated with increased leaf wax content and water retention but reduced sodium uptake. Gene expression analysis indicated that at least four putative miR319 target genes, AsPCF5, AsPCF6, AsPCF8, and AsTCP14, and a homolog of the rice NAC domain gene AsNAC60 were down-regulated in transgenic plants. Our results demonstrate that miR319 controls plant responses to drought and salinity stress. The enhanced abiotic stress tolerance in transgenic plants is related to significant down-regulation of miR319 target genes, implying their potential for use in the development of novel molecular strategies to genetically engineer crop species for enhanced resistance to environmental stress. PMID:23292790

  5. Constitutive expression of a miR319 gene alters plant development and enhances salt and drought tolerance in transgenic creeping bentgrass.

    PubMed

    Zhou, Man; Li, Dayong; Li, Zhigang; Hu, Qian; Yang, Chunhua; Zhu, Lihuang; Luo, Hong

    2013-03-01

    MicroRNA319 (miR319) is one of the first characterized and conserved microRNA families in plants and has been demonstrated to target TCP (for TEOSINTE BRANCHED/CYCLOIDEA/PROLIFERATING CELL FACTORS [PCF]) genes encoding plant-specific transcription factors. MiR319 expression is regulated by environmental stimuli, suggesting its involvement in plant stress response, although experimental evidence is lacking and the underlying mechanism remains elusive. This study investigates the role that miR319 plays in the plant response to abiotic stress using transgenic creeping bentgrass (Agrostis stolonifera) overexpressing a rice (Oryza sativa) miR319 gene, Osa-miR319a. We found that transgenic plants overexpressing Osa-miR319a displayed morphological changes and exhibited enhanced drought and salt tolerance associated with increased leaf wax content and water retention but reduced sodium uptake. Gene expression analysis indicated that at least four putative miR319 target genes, AsPCF5, AsPCF6, AsPCF8, and AsTCP14, and a homolog of the rice NAC domain gene AsNAC60 were down-regulated in transgenic plants. Our results demonstrate that miR319 controls plant responses to drought and salinity stress. The enhanced abiotic stress tolerance in transgenic plants is related to significant down-regulation of miR319 target genes, implying their potential for use in the development of novel molecular strategies to genetically engineer crop species for enhanced resistance to environmental stress. PMID:23292790

  6. Heterologous expression of an uncharacterized universal stress protein gene (SbUSP) from the extreme halophyte, Salicornia brachiata, which confers salt and osmotic tolerance to E. coli.

    PubMed

    Udawat, Pushpika; Mishra, Avinash; Jha, Bhavanath

    2014-02-15

    Salicornia brachiata is an extreme halophyte considered to be a rich source of stress responsive genes and an EST database revealed that 30% of its genes are uncharacterized. In order to ascertain its function, a gene (Sal-E-56) of unknown function was made full length using RACE, cloned and characterized. The full length gene (873 bp; accession no. KF164282) contained an open reading frame (ORF) of 486 bp encoding for a protein that belongs to the universal stress protein (USP) family that was named SbUSP. The SbUSP interacted with adenosine monophosphate and exhibited characteristic motifs, phosphorylation, glycosylation and ATP binding sites. Further, in-silico analyses suggested a probable role in metabolic process of phosphate-containing compounds including signal transduction. In planta transcript profiling exhibited a significant expression response (7.8-fold) to salt stress, additionally abundant of SbUSP transcripts were observed during drought, heat and cold stress, reaching a maximum increase of 3.66-, 2.64- and 2.14-fold, respectively, at 12 or 24h. The heterologous expression of this gene in Escherichia coli provided enhanced stress tolerance and recombinant cells have higher growth rate compared to vector alone and showed growth at up to a 10(-5) dilution in the spot assay. It was predicted that SbUSP may be directly involved in tolerance mechanisms or function as a molecular switch (signaling molecule) to activate the stress adaptive mechanisms. However, further investigation will be required to determine its role as a molecular switch and mode of action during stress. PMID:24291028

  7. Structural characterization of a unique marine animal family 7 cellobiohydrolase suggests a mechanism of cellulase salt tolerance

    PubMed Central

    Kern, Marcelo; McGeehan, John E.; Streeter, Simon D.; Martin, Richard N. A.; Besser, Katrin; Elias, Luisa; Eborall, Will; Malyon, Graham P.; Payne, Christina M.; Himmel, Michael E.; Schnorr, Kirk; Beckham, Gregg T.; Cragg, Simon M.; Bruce, Neil C.; McQueen-Mason, Simon J.

    2013-01-01

    Nature uses a diversity of glycoside hydrolase (GH) enzymes to convert polysaccharides to sugars. As lignocellulosic biomass deconstruction for biofuel production remains costly, natural GH diversity offers a starting point for developing industrial enzymes, and fungal GH family 7 (GH7) cellobiohydrolases, in particular, provide significant hydrolytic potential in industrial mixtures. Recently, GH7 enzymes have been found in other kingdoms of life besides fungi, including in animals and protists. Here, we describe the in vivo spatial expression distribution, properties, and structure of a unique endogenous GH7 cellulase from an animal, the marine wood borer Limnoria quadripunctata (LqCel7B). RT-quantitative PCR and Western blot studies show that LqCel7B is expressed in the hepatopancreas and secreted into the gut for wood degradation. We produced recombinant LqCel7B, with which we demonstrate that LqCel7B is a cellobiohydrolase and obtained four high-resolution crystal structures. Based on a crystallographic and computational comparison of LqCel7B to the well-characterized Hypocrea jecorina GH7 cellobiohydrolase, LqCel7B exhibits an extended substrate-binding motif at the tunnel entrance, which may aid in substrate acquisition and processivity. Interestingly, LqCel7B exhibits striking surface charges relative to fungal GH7 enzymes, which likely results from evolution in marine environments. We demonstrate that LqCel7B stability and activity remain unchanged, or increase at high salt concentration, and that the L. q