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Sample records for hybrid lucerne medicago

  1. Lucerne (Medicago sativa) or grass-clover as cut-and-carry fertilizers in organic agriculture

    NARCIS (Netherlands)

    Burgt, van der G.J.H.M.; Eekeren, van N.J.M.; Scholberg, J.M.S.; Koopmans, C.J.

    2013-01-01

    Onfarm nitrogen fixation is a driving force in organic agriculture. The efficiency with which this nitrogen is used can be increased by using lucerne (Medicago sativa) or grassclover directly as sources of fertilizer on arable land: cutandcarry fertilizers. In two arable crops, the use of lucerne an

  2. Biological nitrogen fixation by lucerne (Medicago sativa L.) in acid soils.

    NARCIS (Netherlands)

    Pijnenborg, J.W.M.

    1990-01-01

    Growth of lucerne( Medicago sativa L.) is poor in soils with values of pH-H2O below 6. This is often due to nitrogen deficiency, resulting from a hampered performance of the symbiosis withRhizobium meliloti. This thesis deals with the factors affecting biological nitrogen fixat

  3. Stoichiometric characteristics of carbon, nitrogen and phosphorus in leaves of differently aged lucerne (Medicago sativa stands

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    Zhennan eWang

    2015-12-01

    Full Text Available Element concentration within a plant which is vital to function maintenance and adaptation to environment, may change with plant growth. However, how carbon (C, nitrogen (N and phosphorus (P vary stoichiometrically with stand growth, i.e. ages or cuts, was still untouched in perennial species. This study tested the hypothesis that lucerne (Medicago sativa C:N, C:P and N:P should change with stand age and cut. Leaf C:N, C:P and N:P changed with stand age, showing various trends in different cuts of lucerne. Generally the greatest stoichiometric ratios were measured in 8 year stand and in the 2nd cut. They were affected significantly and negatively by total N and P concentrations of leaf, but not by organic C concentration. There were significantly positive correlations among leaf C:N, C:P and N:P. However, leaf C:N, C:P and N:P were hardly affected by soil features. Conclusively, lucerne C, N and P stoichiometry are age- and cut-specific, and regulated mainly by leaf N, P concentrations and stoichiometry. There are few correlations with soil fertility. To our knowledge, it is the first try to elucidate the stoichiometry in the viewpoint of age and cut with a perennial herbaceous legume.

  4. Low Level Gamma Spectroscopy Measurements of Radium and Cesium in Lucerne (Medicago Sativa)

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    Fokapić, S.; Bikit, I.; Mrđa, D.; Vesković, M.; Slivka, J.; Mihaljev, Ž.; Ćupić, Ž.

    2007-04-01

    Nineteen years after Chernobyl nuclear accident, activity concentration of 137Cs still could be detected in food and soil samples in Central and Eastern Europe. In this paper radiation levels of radium and cesium in Lucerne will be presented. It is a perennial plant with a deep root system and it is widely grown throughout the world as forage for cattle. The samples of Lucerne were taken from twelve different locations in Vojvodina in the summer period July-September 2004. The samples were specially dried on the air and after that ground, powdered and mineralized by method of dry burning on the temperature of 450°C. Gamma spectrometry measurements of the ash were performed by means of actively shielded germanium detector with maximal background reduction. For cesium 137Cs 10 mBq/kg order of magnitude detection limits were achieved.

  5. Expanding and exploring the diversity of phytoplasmas from lucerne (Medicago sativa)

    Science.gov (United States)

    Gopurenko, David; Fletcher, Murray J.; Liu, Jian; Gurr, Geoff M.

    2016-01-01

    Phytoplasmas are a group of insect-vectored bacteria responsible for disease in many plant species worldwide. Among the crop species affected is the economically valuable forage species lucerne. Here we provide comprehensive molecular evidence for infection in multiple lucerne plants by a phytoplasma not previously known from this plant species. This phytoplasma had a >99% genetic similarity to an unclassified 16S rRNA subgroup previously reported as Stylosanthes little leaf from Stylosanthes spp. and was genetically and symptomatically distinct from a co-occurring but less common 16SrIIA group phytoplasma. Neighbour-joining analyses with publicly available sequence data confirmed the presence of two distinct phytoplasma lineages in the plant population. No PCR detections were made among 38 individuals of 12 co-occurring weed species. Sequence analysis revealed that all nine PCR detections from among 106 individuals of five Hemiptera insect species from the site, three of which had previously been reported as likely vectors, were false positives. This study demonstrates the importance of sequencing to complement PCR detection and avoid potentially inaccurate conclusions regarding vectors, highlights that sampling over a wide spatio-temporal scale is important for vector and alternative host studies, and extends to eight the number of phytoplasma 16 Sr groups known from lucerne. PMID:27886229

  6. Root characters of Lucerne (Medicago sativa L.) under rain-fed and irrigated conditions

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    Raza, Amir; Moghaddam, Ali; Loiskandl, Willibald; Friedel, Jürgen K.; Himmelbauer, Margaritta; Bodner, Gernot

    2010-05-01

    In organic farming, only limited use of selected fertilizers is allowed and plants have to meet their nutritional requirements through mobilization of nutrients provided by organic amendments, crop residue input within the rotation, and released from the soil reservoir. The crop varieties used in such systems shall be efficient in nutrient and water uptake. Root length, surface area and depth distribution are important root characters that demonstrate a potential for nutrient and water uptake. Detailed information on these root characters is lacking for Lucerne, one of the most important legume crop widely used in organic farming. A study was designed to compare three lucerne cultivars from different geographical origin viz. Niva, Mohajaren and Sitel for their root characters in two different sets of experiments planted under rain-fed and irrigated conditions in 2007. The irrigated experiment should provide root traits under potential growth conditions while the rain-fed experiment should highlight root characteristics under water limited conditions. The experiments were conducted on fields of the research station Groß Enzersdorf of the University or Natural Resources and Applied Life Sciences(BOKU), Vienna, Austria. Both experiments were laid out in α-lattice design with two replicates. At the end of vegetation period, root samples were taken for every 30 cm soil profile depth till the depth of 90 cm. From each plot, one sample was taken on the row and two samples between the rows using a cylindrical auger for sampling depth of 0 - 30, 30 - 60 and 60 - 90 cm. Root samples were washed out and analyzed with WinRhizo software to determine root length, surface area, root volume and average diameter. Results revealed that cultivars under rain-fed conditions had higher root length density and surface area than under irrigated conditions. The differences in root parameters estimated for each of the Lucerne cultivars are discussed.

  7. The effect of feeding sulla (Hedysarum coronarium) or lucerne (Medicago sativa) on lamb parasite burdens and development of immunity to gastrointestinal nematodes.

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    Niezen, J H; Charleston, W A G; Robertson, H A; Shelton, D; Waghorn, G C; Green, R

    2002-05-02

    Two experiments investigated the efficacy of the legume Hedysarum coronarium (sulla), which contains condensed tannins (CTs), for reducing gastrointestinal nematode infections relative to lucerne. Experiment 1 was aimed to show whether the lower faecal egg count (FEC) and larval establishment previously reported in lambs grazing sulla were due to direct effects of the forage on Ostertagia circumcincta and Trichostrongylus colubriformis or were mediated through an enhanced immune response. Experiment 2 evaluated the impact of feeding sulla relative to feeding lucerne (Medicago sativa), before, at, or after larval challenge on subsequent FECs and nematode burdens. In experiment 1, 64 Romney lambs were fed either freshly cut lucerne or sulla (32 lambs per herbage) for the duration of the trial. Within each herbage there were four treatment groups (n=8 per group). Initial levels of immunity were assessed in uninfected (UN) lambs which were maintained parasite-free until challenged with 15,000 O. circumcincta and 15,000 T. colubriformis larvae on day 63, and slaughtered on day 81. The other three treatment groups were trickle-infected with each of 5000 O. circumcincta and 5000 T. colubriformis larvae three times per week from day 1 to 35. Non-steroid infected (CONTROL) and steroid-treated (STER) groups were treated with anthelmintic on day 49 and challenged with 15,000 O. circumcincta and 15,000 T. colubriformis on day 63 and slaughtered on day 81. The STER lambs were given dexamethasone trimethylacetate from day 49 to 81 to determine effects of immunity on parasite infection. From day 35 an establishment group (EST) on each herbage was fed a common pelleted lucerne diet and slaughtered on day 56 to determine nematode establishment during trickle-infection. Diet did not affect FECs but feeding lucerne increased (Psulla. O. circumcincta numbers were lower (Psulla than lucerne. The sulla diet was associated with higher (Psulla diet but effects upon T. colubriformis

  8. Lucerne transient streak virus; a Recently Detected Virus Infecting Alfafa (Medicago sativa) in Central Saudi Arabia.

    Science.gov (United States)

    Raza, Ahmed; Al-Shahwan, Ibrahim M; Abdalla, Omer A; Al-Saleh, Mohammed A; Amer, Mahmoud A

    2017-02-01

    A survey was conducted to determine the status of Lucerne transient streak virus (LTSV) in three high-yielding alfalfa regions in central Saudi Arabia (Riyadh, Qassim, and Hail) during 2014. Three hundred and eight symptomatic alfalfa, and seven Sonchus oleraceus samples were collected. DAS-ELISA indicated that 59 of these samples were positive to LTSV. Two isolates of LTSV from each region were selected for molecular studies. RT-PCR confirmed the presence of LTSV in the selected samples using a specific primer pair. Percentage identity and homology tree comparisons revealed that all Saudi isolates were more closely related to each other but also closely related to the Canadian isolate-JQ782213 (97.1-97.6%) and the New Zealand isolate-U31286 (95.8-97.1%). Comparing Saudi isolates of LTSV with ten other sobemoviruses based on the coat protein gene sequences confirmed the distant relationship between them. Eleven out of fourteen plant species used in host range study were positive to LTSV. This is the first time to document that Trifolium alexandrinum, Nicotiana occidentalis, Chenopodium glaucum, and Lathyrus sativus are new host plant species for LTSV and that N. occidentalis being a good propagative host for it.

  9. Lucerne transient streak virus; a Recently Detected Virus Infecting Alfafa (Medicago sativa) in Central Saudi Arabia

    Science.gov (United States)

    Raza, Ahmed; Al-Shahwan, Ibrahim M.; Abdalla, Omer A.; Al-Saleh, Mohammed A.; Amer, Mahmoud A.

    2017-01-01

    A survey was conducted to determine the status of Lucerne transient streak virus (LTSV) in three high-yielding alfalfa regions in central Saudi Arabia (Riyadh, Qassim, and Hail) during 2014. Three hundred and eight symptomatic alfalfa, and seven Sonchus oleraceus samples were collected. DAS-ELISA indicated that 59 of these samples were positive to LTSV. Two isolates of LTSV from each region were selected for molecular studies. RT-PCR confirmed the presence of LTSV in the selected samples using a specific primer pair. Percentage identity and homology tree comparisons revealed that all Saudi isolates were more closely related to each other but also closely related to the Canadian isolate-JQ782213 (97.1–97.6%) and the New Zealand isolate-U31286 (95.8–97.1%). Comparing Saudi isolates of LTSV with ten other sobemoviruses based on the coat protein gene sequences confirmed the distant relationship between them. Eleven out of fourteen plant species used in host range study were positive to LTSV. This is the first time to document that Trifolium alexandrinum, Nicotiana occidentalis, Chenopodium glaucum, and Lathyrus sativus are new host plant species for LTSV and that N. occidentalis being a good propagative host for it. PMID:28167887

  10. Responses of lucerne (Medicago sativa L.) and rhizobia to copper-based fungicide application in two contrasting soils

    Science.gov (United States)

    Schneider, Martin; Dober, Melanie; Jöchlinger, Lisa; Keiblinger, Katharina; Soja, Gerhard; Mentler, Axel; Zechmeister-Boltenstern, Sophie; Bruckner, Alexander; Golestani Fard, Alireza; Wenzel, Walter; Zehetner, Franz

    2016-04-01

    For more than 120 years, salts of copper (Cu) have been used in viticulture to prevent damages by fungal diseases. Due to restrictions in the use of synthetic fungicides and mineral fertilizers, organic viticulture depends on Cu as well as on biological nitrogen fixation. Here, we conducted an eco-toxicological pot experiment with an acidic, sandy soil and a calcareous, loamy soil and incrementally increasing fungicide application rates from 0 to 5000 mg Cu kg-1 soil. Lucerne (Medicago sativa L. cultivar. Plato) was grown in the pots for 3 months under greenhouse conditions. Acetylene reduction assays performed with harvested nodules showed no response to elevated soil Cu concentrations indicating that the nitrogen fixing capacity of rhizobia was not compromised by Cu in our experiment. Nevertheless, the nodule biomass was very sensitive to Cu and strongly decreased due to reduced amounts of fine roots and less energy supply by the plant. Legumes are known to be Cu-sensitive, and our contribution also showed a decrease in harvest by 50 % (EC50) at 21 mg kg-1 plant Cu tissue concentration in the acidic soil and at 30 mg kg-1 in the calcareous soil. This corresponded to diffusional fluxes measured by diffusive gradients in thin films (DGT) of 202 and 368 fmol cm-2 s-1, respectively. DGT measurements showed that in the acidic soil, Cu was 2 to 10 times more available for plants, depending on the concentration applied, than in the calcareous soil. A modeling approach for estimating the effective concentration (EC) by including the DGT-estimated plant Cu content and the pH produced more accurate values (NRMSE of 21.9 to 20.1 %) than EC directly estimated from DGT.

  11. Prediction of the chemical composition and nutritive value of lucerne (Medicago sativa L. by Near Infrared Spectroscopy

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    M. Odoardi

    2010-01-01

    Full Text Available Lucerne is a low input energy efficient crop that improves soil fertility, and its importance is rising with the increase of public interest in sustainable agriculture. Furthermore, it occupies a significant economic position in the animal feed market (i.e. hay, dehydrated forage, pellets and silage products and deserves a particular interest in the Parmigiano-Reggiano and Grana Padano cheese production areas of Northern Italy (Torricelli et al., 2000.

  12. The Hybridization Barrier between Herbaceous Medicago sativa and Woody M. arborea Is Weakened by Selection of Seed Parents

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    Edwin Bingham

    2013-05-01

    Full Text Available Medicago sativa, alfalfa or lucerne, and M. arborea were considered reproductively isolated until recently. Then, in 2003, an alfalfa genotype was identified that produced a few seeds and progeny with hybrid traits after a large number of pollinations by M. arborea. A derivative of this alfalfa genotype also produced a low frequency of progeny with hybrid traits. Thus, the hybridization barrier was weakened by selection of seed parents. Hybrids from both events expressed traits from M. arborea and M. arborea-specific DNA bands, although more of the M. sativa genome was retained, based on the DNA results. Thus, there was chromatin elimination during embryogenesis, resulting in partial hybrids (hereafter hybrids. However, more than 30 hybrids with an array of M. arborea traits have been obtained thus far, and research continues on the nature of the hybrids. Traits have been genetically transmitted in crosses, and selected traits are in use for alfalfa breeding. This paper reviews the first hybrids and then focuses on further weakening of the hybridization barrier with the discovery of a more efficient hybridizer derived from crossing Medicago sativa subspecies, sativa, coerulea and falcata. This genotype was found to have reproductive abnormalities associated with its complex subspecies origin that are best described as hybrid breakdown. In effect, this subspecies derivative is a bridge-cross parent that consistently produces hybrids. Reproductive abnormalities in the bridge-cross parent are reported and discussed.

  13. Response of Root Properties to Tripartite Symbiosis between Lucerne (Medicago sativa L., Rhizobia and Mycorrhiza Under Dry Organic Farming Conditions

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    M. R. Ardakani

    2009-01-01

    Full Text Available Problem statement: It is generally considered that root turnover is a major contributor to organic matter and mineral nutrient cycles in organic managed agroecosystems. Approach: This study designed to investigate whether microbial activity could affect on root properties of Lucerne in an organically managed field under dry weather conditions. The trial was laid out as a factorial experiment in the fields of the University of Natural Resources and Applied Life Sciences, Vienna- Austria at Raasdorf in 2007. The experimental factors of Rhizobium (Sinorhizobium meliloti and Arbuscular Mycorrhiza (AM including Glomus etunicatum, G. intraradices and G. claroideum and irrigation levels were tested. Results: Results showed that increasing water deficit affected root dry weigh, specific root mass and root length significantly at 1% level and co-inoculation of rhizobium and mycorrhiza with irrigation increased all root parameters. Datas of variance analysis for mycorrhizal colonization showed that main effect of using mycorrhiza had significant effects on root parameters at 5 and 1% probability level at first and second harvest, respectively. Results of mean comparisons by Duncans Multiple Range Test showed that mycorrhizal colonization was higher in the inoculated treatments by rhizobium, mycorrhiza and irrigated plots in both harvests. Double interaction of mycorrhiza and irrigation was higher in both harvests (37.05 and 65.73%, respectively. Conclusion: It can be suggested that the tripartite symbiosis of Rhizobium, AM and Lucerne can improve the performance of Lucerne in organic farming and under dry conditions. Such traits could be incorporated into breeding programs to improve drought tolerance especially in organic fields.

  14. Production of 2nd generation bioethanol from lucerne - Optimization of hydrothermal pretreatment

    DEFF Research Database (Denmark)

    Thomsen, Sune T.; Jensen, Morten; Schmidt, Jens E.

    2012-01-01

    Lucerne (Medicago sativa) has many qualities associated with sustainable agriculture such as nitrogen fixation and high biomass yield. Therefore, there is interest in whether lucerne is a suitable biomass substrate for bioethanol production, and if hydrothermal pretreatment (HTT) of lucerne impro...

  15. Production of 2nd generation Bioethanol from Lucerne - Optimization of Hydrothermal Pretreatment

    DEFF Research Database (Denmark)

    Thomsen, Sune Tjalfe; Jensen, Morten; Schmidt, Jens Ejbye

    2012-01-01

    Lucerne (Medicago sativa) has many qualities associated with sustainable agriculture such as nitrogen fixation and high biomass yield. Therefore, there is interest in whether lucerne is a suitable biomass substrate for bioethanol production, and if hydrothermal pretreatment (HTT) of lucerne impro...

  16. Comparative gene expression profiles between heterotic and non-heterotic hybrids of tetraploid Medicago sativa

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    Nettleton Dan

    2009-08-01

    Full Text Available Abstract Background Heterosis, the superior performance of hybrids relative to parents, has clear agricultural value, but its genetic control is unknown. Our objective was to test the hypotheses that hybrids expressing heterosis for biomass yield would show more gene expression levels that were different from midparental values and outside the range of parental values than hybrids that do not exhibit heterosis. Results We tested these hypotheses in three Medicago sativa (alfalfa genotypes and their three hybrids, two of which expressed heterosis for biomass yield and a third that did not, using Affymetrix M. truncatula GeneChip arrays. Alfalfa hybridized to approximately 47% of the M. truncatula probe sets. Probe set signal intensities were analyzed using MicroArray Suite v.5.0 (MAS and robust multi-array average (RMA algorithms. Based on MAS analysis, the two heterotic hybrids performed similarly, with about 27% of genes showing differential expression among the parents and their hybrid compared to 12.5% for the non-heterotic hybrid. At a false discovery rate of 0.15, 4.7% of differentially expressed genes in hybrids (~300 genes showed nonadditive expression compared to only 0.5% (16 genes in the non-heterotic hybrid. Of the nonadditively expressed genes, approximately 50% showed expression levels that fell outside the parental range in heterotic hybrids, but only one of 16 showed a similar profile in the non-heterotic hybrid. Genes whose expression differed in the parents were three times more likely to show nonadditive expression than genes whose parental transcript levels were equal. Conclusion The higher proportions of probe sets with expression level that differed from the parental midparent value and that were more extreme than either parental value in the heterotic hybrids compared to a non-heterotic hybrid were also found using RMA. We conclude that nonadditive expression of transcript levels may contribute to heterosis for biomass

  17. Replacement of grass and maize silages with lucerne silage: effects on performance, milk fatty acid profile and digestibility in Holstein-Friesian dairy cows.

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    Sinclair, L A; Edwards, R; Errington, K A; Holdcroft, A M; Wright, M

    2015-12-01

    In total, 20 multiparous Holstein-Friesian dairy cows received one of four diets in each of four periods of 28-day duration in a Latin square design to test the hypothesis that the inclusion of lucerne in the ration of high-yielding dairy cows would improve animal performance and milk fatty acid (FA) composition. All dietary treatments contained 0.55 : 0.45 forage to concentrates (dry matter (DM) basis), and within the forage component the proportion of lucerne (Medicago sativa), grass (Lolium perenne) and maize silage (Zea mays) was varied (DM basis): control (C)=0.4 : 0.6 grass : maize silage; L20=0.2 : 0.2 : 0.6 lucerne : grass : maize silage; L40=0.4 : 0.6 lucerne : maize silage; and L60=0.6 : 0.4 lucerne : maize silage. Diets were formulated to contain a similar CP and metabolisable protein content, with the reduction of soya bean meal and feed grade urea with increasing content of lucerne. Intake averaged 24.3 kg DM/day and was lowest in cows when fed L60 (P0.05) by dietary treatment. Digestibility of DM, organic matter, CP and fibre decreased (Psilage can be replaced with first cut lucerne silage without any detrimental effect on performance and an improvement in the milk FA profile, although intake and digestibility was lowest and plasma urea concentrations highest in cows when fed the highest level of inclusion of lucerne.

  18. [Physical localization of ribosomal genes and chromosome DAPI banding by in situ hybridization in Medicago sativa L].

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    Chen, Jian-Min; Hong, Yi-Huan; Wang, You-Ping; Bowley, Steve; Wan, Jian-Min

    2006-02-01

    Physical localization of ribosomal genes in diploid and tetraploid alfalfa (Medicago. sativa) was studied using fluorescent in situ hybridization (FISH). It was revealed that 45s gene was only located at nucleolus organizer region (NOR) with a single locus in both diploid and tetraploid alfalfa, while 5s gene had 2-3 loci on chromosomes. Using the genomic DNA from M. coerulea and M. falcata as probe to hybridize with tetraploid species in alfalfa, both diploid species were successfully hybridized with tetraploid chromosomes, only showing the difference in hybridization signals in different numbers of chromosomes. Chromosomes of alfalfa exhibited DAPI banding by FISH analysis. In general, the patterns of distribution of DAPI banding were consistent with C-banding for M. coerulea. The possible origination of tetraploid alfalfa was discussed based on DAPI banding patterns and FISH analysis for ribosomal genes .

  19. Sapogenin content variation in Medicago inter-specific hybrid derivatives highlights some aspects of saponin synthesis and control.

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    Carelli, Maria; Biazzi, Elisa; Tava, Aldo; Losini, Ilaria; Abbruscato, Pamela; Depedro, Claudia; Scotti, Carla

    2015-04-01

    In the Medicago genus, saponins are a complex mixture of triterpene glycosides showing a broad spectrum of biological properties. Here we analyzed the variation in the sapogenin content and composition of inter-specific hybrid Medicago sativa × Medicago arborea derivatives to highlight the pattern of this variation in plant organs (leaves/roots) and the possible mechanisms underlying it. In Sativa Arborea Cross (SAC) leaves and roots, saponins and sapogenins were evaluated using chromatographic methods. Phenotypic correlations between sapogenin content and bio-agronomic traits were examined. Expression studies on β-amyrin synthase and four cytochromes P450 (CYPs) involved in sapogenin biosynthesis and sequence analysis of the key gene of the hemolytic sapogenin pathway (CYP716A12) were performed. Chromatographic analyses revealed a different pattern of among-family variation for hemolytic and nonhemolytic sapogenins and saponins and for the two organs/tissues. Different correlation patterns of gene expression in roots and leaves were found. Diachronic analysis revealed a relationship between sapogenin content and gene transcriptional levels in the early stages of the productive cycle. The results suggest that there are different control mechanisms acting on sapogenin biosynthesis for leaves and roots, which are discussed. A key role for medicagenic acid in the control of sapogenin content in both the tissues is proposed and discussed.

  20. Biogenic amines and hygienic quality of lucerne silage

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    Mlejnkova Veronika

    2016-01-01

    Full Text Available This experiment examined the influence of two different silage additives of biological (Lactococcus lactis, Lactobacillus plantarum, Enterococcus faecium, enzyme xylanase and chemical (43% formic acid, 30% ammonium formate, 10% propionic acid, 2% benzoic acid types on biogenic amines concentration, nutrient content, fermentation process, and microbiologic indicators in lucerne (Medicago sativa silage after 90 days of fermentation. The biological additive significantly (P < 0.05 increased putrescine (+51%, lactic acid (+11% and protein content (+11% in comparison with control silage. It significantly decreased cadaverine (−29%, histamine (−57%, spermidine (−15%, spermine (−55%, acetic acid (−40%, ethanol (−55%, ammonium (−25% and ash (−9%. After the chemical-additive treatment, greater amounts of histamine and tyramine were recorded. Significant decrease was observed in the concentrations of putrescine (−18%, cadaverine (−55%, spermidine (−47%, spermine (−45%, lactic acid (−16%, acetic acid (−46%, ammonium (−59%, ash (−13% and fat (−24%. Populations of bacteria associated with lactic acid fermentation, moulds, yeasts, enterobacteria and total microorganisms count were also influenced. Both biological and chemical additives can be highly recommended for producing high-quality silages meeting hygienic requirements. In lucerne silage, the chemical preservative showed a stronger effect in achieving the health safety of silage compared to the biological inoculant.

  1. Floral Properties of Different Lucerne Varieties and Their Effects on Bee Visitation

    Institute of Scientific and Technical Information of China (English)

    Jiang; Hua; Shan; Guilian; Duan; Xinhui; Bi; Yufen; He; Chenggang

    2014-01-01

    Lucerne( Medicago sativa L.) is a plant of strict allogamy,and its pollination relies on bees mainly. Genetic variations of lucerne floral properties,including receptacle diameter,coronary length,number of flowers per raceme,number of racemes per twig,number of flowers per square metre,percentage of tripped flowers,nectar production,sugar concentration in nectar and contents of sucrose,fructose and glucose in nectar,have been studied with morphological markers,and floral properties of ten lucerne cultivars were also investigated to determine their role in number of visiting bees and to provide a basis for the evaluation of mutant flowers for visitation by bees. The results showed CV( coefficient of variation) of floral properties was from 0. 80% to 92. 30%,of which the content of glucose was the most significant one with variation from 0. 01 to 0. 53 μmol /L( P < 0. 05),and the sugar concentration was the most insignificant one( P > 0. 05). The significant order of floral properties affecting the number of visiting bees was that the nectar production per square metre( r = 0. 93,P < 0. 01) was in the first place,followed by the number of flowers per square metre( r = 0. 92,P < 0. 01),sucrose concentration of nectar sugar( r = 0. 82,P < 0. 05),coronary length( r = 0. 77,P < 0. 05) and nectar production per flower( r = 0. 71,P < 0. 05).

  2. Regeneration of intergeneric somatic hybrids by protoplast fusion between Onobrychis viciaefolia and Medicago sativa

    Institute of Scientific and Technical Information of China (English)

    徐子勤; 贾敬芬

    1997-01-01

    Protoplast fusion was induced between sainfoin and alfalfa by an improved polyethyleneglycol (PEG) method. The intergeneric somatic calluses were selected based on complementation of hydroxyproline-resistance of sainfoin and hormone autonomy growth of alfalfa transformation cell line. 17 somatic hybrid plantlets were regenerat-ed. PEG could induce the tight agglutination of protoplasts. During diluting and washing process, cyclization of the linked membrane and formation of vesicle-like structures were observed, resulting in protoplast fusion. 5%-10% glycerol supplemented in the fusion inducing solution markedly increased the frequency of heterogeneous fusion. Better fusion results were obtained when mixed protoplast suspension was dripped in petri dishes in which PEG solution was previously placed. Chromosome number of regenerated hybrid buds varied from 30 to 60. The genome of hybrids in-cluded the small chromosome from sainfoin and two chromosomes with two clear constrictions from alfalfa. The hybrid

  3. Multiple-purpose trees for pastoral farming in New Zealand: with emphasis on tree legumes. [Lucerne Tree: Medick Tree

    Energy Technology Data Exchange (ETDEWEB)

    Davies, D.J.G.; Macfarlane, R.P.

    1979-01-01

    The potential for soil conservation and agroforestry of several native and exotic legumes is discussed. Flowering period, chemical composition of leaves/pods, hardiness to frost and drought, timber value, forage potential for livestock and bees, ornamental value and other products are tabulated with information on up to 38 species. Two low-growing species that have proved useful for slope stabilization as well as forage are tree lucerne (Cytisus palmensis) and tree medick (Medicago arborea), the latter being shrubby and more suitable for cold districts. Gleditsia triacanthos is recommended as a shade and fodder tree for farm pasture.

  4. Natural occurrence of entomophthoroid fungi of aphid pests on Medicago sativa L. in Argentina.

    Science.gov (United States)

    Manfrino, Romina G; Zumoffen, Leticia; Salto, César E; Lastra, Claudia C López

    2014-01-01

    Four species of entomophthoroid fungi, Pandora neoaphidis (Entomophthorales: Entomophthoraceae), Zoophthora radicans (Entomophthorales: Entomophthoraceae), Entomophthora planchoniana (Entomophthorales: Entomophthoraceae) and Neozygites fresenii (Neozygitales: Neozygitaceae) were found to infect Aphis craccivora, Therioaphis trifolii, and Acyrthosiphon pisum and unidentified species of Acyrthosiphon on lucerne in Argentina. Samples were collected from five sites (Ceres, Rafaela, Sarmiento, Monte Vera and Bernardo de Irigoyen) in the province of Santa Fe. In this study, Zoophthora radicans was the most important pathogen and was recorded mainly on Acyrthosiphon sp. Zoophthora radicans was successfully isolated and maintained in pure cultures. This study is the first report of entomophthoroid fungi infecting lucerne (Medicago sativa L.) aphids in Argentina.

  5. Natural occurrence of entomophthoroid fungi of aphid pests on Medicago sativa L. in Argentina

    Directory of Open Access Journals (Sweden)

    Romina G Manfrino

    Full Text Available Four species of entomophthoroid fungi, Pandora neoaphidis (Entomophthorales: Entomophthoraceae, Zoophthora radicans (Entomophthorales: Entomophthoraceae, Entomophthora planchoniana (Entomophthorales: Entomophthoraceae and Neozygites fresenii (Neozygitales: Neozygitaceae were found to infect Aphis craccivora, Therioaphis trifolii, and Acyrthosiphon pisum and unidentified species of Acyrthosiphon on lucerne in Argentina. Samples were collected from five sites (Ceres, Rafaela, Sarmiento, Monte Vera and Bernardo de Irigoyen in the province of Santa Fe. In this study, Zoophthora radicans was the most important pathogen and was recorded mainly on Acyrthosiphon sp. Zoophthora radicans was successfully isolated and maintained in pure cultures. This study is the first report of entomophthoroid fungi infecting lucerne (Medicago sativa L. aphids in Argentina.

  6. Divergence of compost extract and bio-organic manure effects on lucerne plant and soil

    Directory of Open Access Journals (Sweden)

    Haiyan Ren

    2017-09-01

    Full Text Available Aim Application of organic materials into agricultural systems enhances plant growth and yields, and improves soil fertility and structure. This study aimed to examine the effects of “compost extract (CE”, a soil conditioner, and bio-organic manure (BOM on the growth of lucerne (Medicago sativa, and compare the efficiency between BOM (including numbers of microorganisms and CE (including no added microorganisms. Method A greenhouse experiment was conducted with four soil amendment treatments (control, BOM, CE and CEBOM, and was arranged in a completely randomized design with 10 replicates for each treatment. Plant biomass, nutritive value and rhizobia efficacy as well as soil characteristics were monitored. Result CE rather than BOM application showed a positive effect on plant growth and soil properties when compared with the control. Lucerne nodulation responded equally to CE addition and rhizobium inoculation. CE alone and in combination with BOM significantly increased plant growth and soil microbial activities and improved soil structure. The synergistic effects of CE and BOM indicate that applying CE and BOM together could increase their efficiency, leading to higher economic returns and improved soil health. However, CE alone is more effective for legume growth since nodulation was suppressed by nitrogen input from BOM. CE had a higher efficiency than BOM for enriching soil indigenous microorganisms instead of adding microorganisms and favouring plant nodulation.

  7. Digestate as nutrient source for biomass production of sida, lucerne and maize

    Science.gov (United States)

    Bueno Piaz Barbosa, Daniela; Nabel, Moritz; Horsch, David; Tsay, Gabriela; Jablonowski, Nicolai

    2014-05-01

    Biogas as a renewable energy source is supported in many countries driven by climate and energy policies. Nowadays, Germany is the largest biogas producer in the European Union. A sustainable resource management has to be considered within this growing scenario of biogas production systems and its environmental impacts. In this respect, studies aiming to enhance the management of biogas residues, which represents a valuable source of nutrients and organic fertilization, are needed. Our objective was to evaluate the digestate (biogas residue after fermentation process) application as nutrient source for biomass production of three different plants: sida (Sida hermaphrodita - Malvaceae), lucerne (Medicago sativa - Fabaceae) and maize (Zea mays - Poaceae). The digestate was collected from an operating biogas facility (fermenter volume 2500m³, ADRW Natur Power GmbH & Co.KG Titz/Ameln, Germany) composed of maize silage as the major feedstock, and minor amounts of chicken manure, with a composition of 3,29% N; 1,07% P; 3,42% K; and 41,2% C. An arable field soil (Endogleyic Stagnosol) was collected from 0-30 cm depth and 5 mm sieved. The fertilizer treatments of the plants were established in five replicates including digestate (application amount equivalent to 40 t ha-1) and NPK fertilizer (application amount equivalent to 200:100:300 kg ha-1) applications, according to the recommended agricultural doses, and a control (no fertilizer application). The digestate and the NPK fertilizer were thoroughly mixed with the soil in a rotatory shaker for 30 min. The 1L pots were filled with the fertilized soil and the seedlings were transplanted and grown for 30 days under greenhouse conditions (16 h day/8 h night: 24ºC/18ºC; 60% air humidity). After harvesting, the leaf area was immediately measured, and the roots were washed to allow above and below-ground biomass determination. Subsequently, shoots and roots were dried at 60ºC for 48 hours. The biomass and leaf area of sida

  8. Impact of Brassica and Lucerne Finishing Feeds and Intramuscular Fat on Lamb Eating Quality and Flavor. A Cross-Cultural Study Using Chinese and Non-Chinese Australian Consumers.

    Science.gov (United States)

    Frank, Damian; Watkins, Peter; Ball, Alex; Krishnamurthy, Raju; Piyasiri, Udayasika; Sewell, James; Ortuño, Jordi; Stark, Janet; Warner, Robyn

    2016-09-14

    Use of forage brassicas (Brassica napus) and lucerne (alfalfa; Medicago sativa) as ruminant feeds has been linked to unacceptable flavors in sheepmeat. Lambs from low and high intramuscular fat sires were allocated to one of four finishing feeds-perennial ryegrass (Lolium perenne), lucerne, and two brassica forages-for a 6 week period. Grilled loins (Longissimus thoracis et lumborum) were subjected to chemical and sensory analysis by a trained panel and also evaluated by non-Chinese and Chinese background Australian consumers. Consumer liking was similar for both groups, and liking was highest for the brassica- and lucerne-finished lamb, especially from high intramuscular fat sires. No evidence of a distinctive lucerne- or brassica-induced flavor taint was measured by the trained panel or gas chromatography-mass spectrometry-olfactometry. The diets influenced the composition of lipids and branched-chain fatty acids in the subcutaneous fat, and the concentration of total branched-chain fatty acids was positively correlated with flavor and overall liking. Significantly higher levels of key aroma volatiles were measured in the higher fat samples.

  9. Physiological and molecular characterization of lucerne (Medicago sativa L.) germplasm with improved seedling freezing tolerance

    Science.gov (United States)

    We conducted greenhouse experiments to compare 14 alfalfa germplasms for their survival following freezing. Among these germplasms are collections adapted to the Grand River National Grasslands in South Dakota. Our hypothesis was that these collections developed tolerance to survive the frigid gro...

  10. Genome sequence of the Medicago-nodulating Ensifer meliloti commercial inoculant strain RRI128.

    Science.gov (United States)

    Reeve, Wayne; Ballard, Ross; Drew, Elizabeth; Tian, Rui; Bräu, Lambert; Goodwin, Lynne; Huntemann, Marcel; Han, James; Tatiparthi, Reddy; Chen, Amy; Mavrommatis, Konstantinos; Markowitz, Victor; Palaniappan, Krishna; Ivanova, Natalia; Pati, Amrita; Woyke, Tanja; Kyrpides, Nikos

    2014-06-15

    Ensifer meliloti strain RRI128 is an aerobic, motile, Gram-negative, non-spore-forming rod. RRI128 was isolated from a nodule recovered from the roots of barrel medic (Medicago truncatula) grown in the greenhouse and inoculated with soil collected from Victoria, Australia. The strain is used in commercial inoculants in Australia. RRI128 nodulates and forms an effective symbiosis with a diverse range of lucerne cultivars (Medicago sativa) and several species of annual medic (M. truncatula, Medicago littoralis and Medicago tornata), but forms an ineffective symbiosis with Medicago polymorpha. Here we describe the features of E. meliloti strain RRI128, together with genome sequence information and annotation. The 6,900,273 bp draft genome is arranged into 156 scaffolds of 157 contigs, contains 6,683 protein-coding genes and 87 RNA-only encoding genes, and is one of 100 rhizobial genomes sequenced as part of the DOE Joint Genome Institute 2010 Genomic Encyclopedia for Bacteria and Archaea-Root Nodule Bacteria (GEBA-RNB) project.

  11. Assessing the Blue and Green Water Footprint of Lucerne for Milk Production in South Africa

    OpenAIRE

    Morne E. Scheepers; Henry Jordaan

    2016-01-01

    The Global Water Footprint Standard approach was used to calculate the volumetric blue and green water footprint indicator for lucerne production as important feed for dairy cows in a major lucerne production region in South Africa. The degree of sustainability of water use then was assessed by comparing water use to water availability for the region. The results show a volumetric water footprint indicator of 378 m3/tonne of lucerne. Of the total blue and green water footprint, 55% is green w...

  12. Alfalfa (Medicago Sativa L As A Promising Forage In Indonesia

    Directory of Open Access Journals (Sweden)

    Sajimin

    2011-06-01

    Full Text Available Alfalfa (Medicago sativa L or Lucerne is a perennial herbaceous legume with superior forage quality. It is the most important forage crop in the world and it was the first domesticated forage crop. Alfalfa is able to fix nitrogen from the air through a symbiotic relationship with Rhizobium bacteria with N production 7.85 – 10.37 g/m2. Its rooting system can reach 4.5 m that allows it to escape drought. Forage production can reach 15.48 tons of dry matter per ha/year and containing 18.0 – 29.1 % crude protein. Plants can live 3 to 12 years depending on climatic conditions and crop varieties. However, alfalfa is not a tropical plant, thus it has not been widely cultivated in Indonesia. The problem of alfalfa cultivation are high pest attacks and competition with weeds. Therefore, alfalfa cultivation requires attention and good management to obtain optimum yield.

  13. Flood-hazard study: 100-year flood stage for Lucerne Lake, San Bernadino County, California

    Science.gov (United States)

    Busby, Mark William

    1977-01-01

    A study of the flood hydrology of Lucerne Valley, Calif., was made to develop the 100-year stage for Lucerne Lake. Synthetic-hydrologic techniques were used; and the 100-year flood stage was estimated to be at an elevation of 2,849.3 feet above mean sea level. Channel dimensions were measured at 59 sites in Lucerne Valley. Dranage area-discharge relations developed from channel-geometry data for sites nearby were used to estimate the discharge at 12 additional sites where channel geometry could not be measured. In order to compute the total volume discharge into the playa, the peak discharges were converted to volumes. From the Apple Valley report (Busby, 1975) the equation formulated from the relation between peak discharge and flood volume for the deserts of California was used to compute the flood volumes for routing into Lucerne Lake. (Woodard-USGS)

  14. Alfalfa (Medicago sativa L.).

    Science.gov (United States)

    Fu, Chunxiang; Hernandez, Timothy; Zhou, Chuanen; Wang, Zeng-Yu

    2015-01-01

    Alfalfa (Medicago sativa L.) is a high-quality forage crop widely grown throughout the world. This chapter describes an efficient protocol that allows for the generation of large number of transgenic alfalfa plants by sonication-assisted Agrobacterium-mediated transformation. Binary vectors carrying different selectable marker genes that confer resistance to phosphinothricin (bar), kanamycin (npt II), or hygromycin (hph) were used to generate transgenic alfalfa plants. Intact trifoliates collected from clonally propagated plants in the greenhouse were sterilized with bleach and then inoculated with Agrobacterium strain EHA105. More than 80 % of infected leaf pieces could produce rooted transgenic plants in 4-5 months after Agrobacterium-mediated transformation.

  15. In vitro digestibility of lucerne hay using bag method

    Directory of Open Access Journals (Sweden)

    constantin gavan

    2013-10-01

    Full Text Available A filter bag method was used for estimating apparent dry matter (DM digestibility, apparent digestible organic matter in DM, true DM digestibility, true digestible organic matter in DM and Digestibility of neutral detergent fibre. The forage sample analysed comprised tree plant parts (whole, leaf and stem of alfalfa (Medicago sativa, one degree of particle breakdown (1 mm sieve size at miliing and two field replicates at Agricultural Research and Developement Station (ARDS Șimnic-Craiova. Rumen fluid was used from two cannulated dairy cows.The use of filter bags can give acceptable results for the in vitro digestibility of forages. The escape of soluble matter from bags with samples high in solubles could influence the microbial population and hence increase cell wall degradation in bags with samples low in soluble matter, if  all are in the same incubation vessel.

  16. 肇东苜蓿与三种国外引进苜蓿品种间杂交的初步研究%Preliminary Study on Intervarietal Hybridization of Medicago sativa L.cv.Zhaodong and Three Introduced Abroad Alfalfa

    Institute of Scientific and Technical Information of China (English)

    刘凤歧; 张月学; 唐凤兰; 陈晶; 韩微波; 刘杰淋; 尚晨

    2012-01-01

    Heilongjiang is a high-latitude alpine regions,so breeding high-yield,cold resistant and adaptable Medicago sativa L.varieties become the primary breeding goal.The reciprocal intervarietal hybridizations between local variety Medicago sativa L.cv.Zhaodong of cold hardiness and adaptability and three abroad varieties of alfalfa of high yield were undertaken using conventional hybridization methods.Three abroad varieties of alfalfa included WL323 introducing from the USA,Pleven6 introducing from Bulgarian and Beza87 introducing from Russian.Meantime,pollen activities were detected by the method of in vitro germination,and pod bearing rates were investigated and analyzed.The results showed that:there were significant differences in pod bearing rate among male and female parents,and extremely significant differences existed among cross combination.The highest pod bearing rate of reciprocal cross was between Medicago sativa L.cv.Zhangdong and WL323,which laid the foundation of parent selection in cross breeding of alfalfa and provided the basis material for breeding new varieties.%黑龙江属高纬高寒地区,培育高产、抗寒、适应性强的品种成为紫花苜蓿(Medicago sativa L.)育种的首要目标,采用常规杂交方法对抗寒性、适应性强的地方品种肇东苜蓿(Medicago sativa L.cv.Zhaodong)和国外引进的3种高产苜蓿:美国苜蓿WL323、保加利亚苜蓿Pleven6、俄罗斯苜蓿Beza87分别进行正反品种间杂交,利用离体萌发法对杂交亲本的花粉活性进行检测,以及杂交结荚率等数据进行统计分析。结果表明:父、母本对结荚率影响显著,不同杂交组合结荚率差异极显著,肇东苜蓿与WL323正反交的结荚率高于其它杂交组合,为苜蓿杂交育种亲本选配奠定基础,同时为苜蓿杂交新品种的选育提供了基础材料。

  17. A gene encoding a protein with a proline-rich domain (MtPPRD1), revealed by suppressive subtractive hybridization (SSH), is specifically expressed in the Medicago truncatula embryo axis during germination.

    Science.gov (United States)

    Bouton, Sophie; Viau, Laure; Lelièvre, Eric; Limami, Anis M

    2005-03-01

    A gene MtPPRD1, encoding a protein of 132 amino acids containing a proline-rich domain (PRD), has been revealed by suppressive subtractive hybridization (SSH) with two mRNA populations of embryo axes harvested immediately before and after radicle emergence. Although at the protein level MtPPRD1 showed low homology with plant lipid transfer proteins (LTPs), it did exhibit the eight cysteine residues conserved in all plant LTPs, a characteristic signature that allows the formation of a hydrophobic cavity adapted for loading hydrophobic molecules. Expression studies of MtPPRD1 have been carried out by quantitative real time RT-PCR throughout germination and post-germination processes in control seeds and seeds in which germination was delayed by abscisic acid (ABA) or the glutamine synthetase inhibitor methionine sulphoximine (MSX) treatments. The results showed that MtPPRD1 expression is developmentally regulated, induced in the embryo axis immediately before radicle emergence, reaches its maximum expression and declines during the early post-germination phase. Organ specificity studies showed that, except for a low and probably constitutive expression in roots, MtPPRD1 is specifically expressed in the embryo axis. Based on both experimental and in silico studies several putative roles are proposed for MtPPRD1 in Medicago truncatula, this protein can intervene (i) as an LTP in membrane biogenesis and regulation of the intracellular fatty acid pool by binding and transferring fatty acids and phospholipids between membranes, (ii) in the control of a developmental process specific to late germination and to early phases of post-germination, and (iii) and/or pathogen defence.

  18. Phenanthrene uptake by Medicago sativa L. under the influence of an arbuscular mycorrhizal fungus

    Energy Technology Data Exchange (ETDEWEB)

    Wu Naiying [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, PO Box 2871, Beijing 100085 (China); Department of Chemistry, Shangqiu Normal College, Shangqiu 476000 (China); Huang Honglin [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, PO Box 2871, Beijing 100085 (China); Zhang Shuzhen, E-mail: szzhang@rcees.ac.c [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, PO Box 2871, Beijing 100085 (China); Zhu Yongguan [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, PO Box 2871, Beijing 100085 (China); Christie, Peter [Agri-Environment Branch, Agriculture Food and Environmental Science Division, Agri-Food and Biosciences Institute, Newforge Lane, Belfast BT9 5PX (United Kingdom); Zhang Yong [State Key Laboratory of Marine Environmental Science, Environmental Science Research Centre, Xiamen University, Xiamen 361005 (China)

    2009-05-15

    Phenanthrene uptake by Medicago sativa L. was investigated under the influence of an arbuscular mycorrhizal fungus. Inoculation of lucerne with the arbuscular mycorrhizal fungus Glomus etunicatum L. resulted in higher phenanthrene accumulation in the roots and lower accumulation in the shoots compared to non-mycorrhizal controls. Studies on sorption and desorption of phenanthrene by roots and characterization of heterogeneity of mycorrhizal and non-mycorrhizal roots using solid-state {sup 13}C nuclear magnetic resonance spectroscopy ({sup 13}C NMR) demonstrated that increased aromatic components due to mycorrhizal inoculation resulted in enhanced phenanthrene uptake by the roots but lower translocation to the shoots. Direct visualization using two-photon excitation microscopy (TPEM) revealed higher phenanthrene accumulation in epidermal cells of roots and lower transport into the root interior and stem in mycorrhizal plants than in non-mycorrhizal controls. These results provide some insight into the mechanisms by which arbuscular mycorrhizal inoculation may influence the uptake of organic contaminants by plants. - Colonization by an arbuscular mycorrhizal fungus promoted root uptake and decreased shoot uptake of phenanthrene by Medicago sativa L.

  19. The Medicago sativa gene index 1.2: a web-accessible gene expression atlas for investigating expression differences between Medicago sativa subspecies

    Science.gov (United States)

    Alfalfa (Medicago sativa L.) is the primary forage legume crop species in the United States and plays essential economic and ecological roles in agricultural systems across the country. Modern alfalfa is the result of hybridization between tetraploid M. sativa ssp. sativa and M. sativa ssp. falcata....

  20. Genome sequence of Ensifer meliloti strain WSM1022; a highly effective microsymbiont of the model legume Medicago truncatula A17.

    Science.gov (United States)

    Terpolilli, Jason; Hill, Yvette; Tian, Rui; Howieson, John; Bräu, Lambert; Goodwin, Lynne; Han, James; Liolios, Konstantinos; Huntemann, Marcel; Pati, Amrita; Woyke, Tanja; Mavromatis, Konstantinos; Markowitz, Victor; Ivanova, Natalia; Kyrpides, Nikos; Reeve, Wayne

    2013-12-20

    Ensifer meliloti WSM1022 is an aerobic, motile, Gram-negative, non-spore-forming rod that can exist as a soil saprophyte or as a legume microsymbiont of Medicago. WSM1022 was isolated in 1987 from a nodule recovered from the roots of the annual Medicago orbicularis growing on the Cyclades Island of Naxos in Greece. WSM1022 is highly effective at fixing nitrogen with M. truncatula and other annual species such as M. tornata and M. littoralis and is also highly effective with the perennial M. sativa (alfalfa or lucerne). In common with other characterized E. meliloti strains, WSM1022 will nodulate but fixes poorly with M. polymorpha and M. sphaerocarpos and does not nodulate M. murex. Here we describe the features of E. meliloti WSM1022, together with genome sequence information and its annotation. The 6,649,661 bp high-quality-draft genome is arranged into 121 scaffolds of 125 contigs containing 6,323 protein-coding genes and 75 RNA-only encoding genes, and is one of 100 rhizobial genomes sequenced as part of the DOE Joint Genome Institute 2010 Genomic Encyclopedia for Bacteria and Archaea-Root Nodule Bacteria (GEBA-RNB) project.

  1. Effects of the use of acetic acid as the conservant in lucerne ensiling

    Directory of Open Access Journals (Sweden)

    Đorđević Nenad

    2004-01-01

    Full Text Available The influence of acetic acid as the chemical conservant in three doses (4, 6 8 g/kg green mass on the intensity of fermentation and proteolysis in lucerne silage was investigated. On the basis of chemical analysis, it was found that with the increase of conservant dose the pH value decreased aminogenesis and nitrogen solubility was limited. In silages treated the absolute and relative domination of acetic acid was found in total acid content. The increase of free and bonded acetic acid was discovered with the increase of conservant dose. Free butyric acid was not detected, while bonded butyric acid was present in negligible concentration, without effect on silage quality. Compared to control silage (III quality class according to DLG and Zelter method, a significant increase of acetic acid in silages resulted in the decline of their quality, and they were ranked as not useful (V quality class according to DLG method, or on the margin of usefulness (IV quality class according to Zelter method. In spite of some foreign references, domestic experiences show that acetic acid is not an effective conservant and it is not recommended for that use for lucerne that is not simple to ensile.

  2. Chemical composition of lucerne leaf extract (EFL) and its applications as a phytobiotic in human nutrition.

    Science.gov (United States)

    Gaweł, Eliza

    2012-01-01

    Lucerne, a valuable plant grown mainly for animal feed, is rich in protein, minerals (Ca, Cu, Fe, Mg, Mn, P, Zn, Si), vitamins (A, B, C, D, E, K, U), phytochemical substances (carotene, chlorophyll, coumarins, isoflavones, alkaloids, saponins), contains secondary metabolites of plants (phytoestrogens: isoflavones and coumestrol), and antinutritional components (phytates, L-canavanine, saponins). It may be used as a dietary supplement in human nutrition. The proteins found in lucerne are comprised of numerous exogenous and semi-exogenous amino acids which are desirable for human body. Extract from the leaves of alfalfa (EFL - l'Extrait Foliaire de Luzerne) practically does not contain mycotoxins and pesticide pollutants. It is a completely natural product, safe even in a long-term supplementation. Extract from the leaves of alfalfa has a positive, multidirectional impact on the human body. It increases the level of estrogen, prevents atherosclerosis, helps blood circulation and strenghtens immunity, protects against the development of dangerous diseases of the digestive tract, combats anemia and many other health ailments. The results of preclinical studies indicate that alfalfa leaf extract enriched with vitamin C (EFL) can be a dietary supplement supporting the human body in fighting malnutrition, ischemic diseases, and various disorders of digestive tract. It also strengthens and enhances immunity.

  3. Chemical composition of lucerne leaf extract (EFL and its applications as a phytobiotic in human nutrition

    Directory of Open Access Journals (Sweden)

    Eliza Gaweł

    2012-09-01

    Full Text Available   Lucerne, a valuable plant grown mainly for animal feed, is rich in protein, minerals (Ca, Cu, Fe, Mg, Mn, P, Zn, Si, vitamins (A, B, C, D, E, K, U, phytochemical substances (carotene, chlorophyll, coumarins, isoflavones, alkaloids, saponins, contains secondary metabolites of plants (phytoestrogens: isoflavones and coumestrol, and antinutritional components (phytates, L-canavanine, saponins. It may be used as a dietary supplement in human nutrition. The proteins found in lucerne are comprised of numerous exogenous and semi-exogenous amino acids which are desirable for human body. Extract from the leaves of alfalfa (EFL – l’Extrait Foliaire de Luzerne practically does not contain mycotoxins and pesticide pollutants. It is a completely natural product, safe even in a long-term supplementation. Extract from the leaves of alfalfa has a positive, multidirectional impact on the human body. It increases the level of estrogen, prevents atherosclerosis, helps blood circulation and strenghtens immunity, protects against the development of dangerous diseases of the digestive tract, combats anemia and many other health ailments. The results of preclinical studies indicate that alfalfa leaf extract enriched with vitamin C (EFL can be a dietary supplement supporting the human body in fighting malnutrition, ischemic diseases, and various disorders of digestive tract. It also strengthens and enhances immunity.  

  4. Oxidative Stability of Ostrich Meat Related to Duration of Linseed and Lucerne Supplementation to the Bird's Diet

    Directory of Open Access Journals (Sweden)

    Jóźwik Artur

    2015-04-01

    Full Text Available The effect of dietary linseed and lucerne supplementation on the oxidative stability of ostrich meat expressed by changes in concentrations of malondialdehyde (MDA and glutathione (GSH, and in activity of superoxide dismutase (SOD, was studied. The feeding regimens were as follows: C – control group, L – 4% supplement of linseed, L-L45, L-L55, L-L65, and L-L75 – 4% supplement of linseed and supplement of lucerne added to the birds’ diet at 45, 55, 65, and 75 kg b.w. The highest level of GSH was recorded in L-L65 group, whereas the highest activity of SOD was observed in C, L-L65 and L-L75 groups. Among all groups, the long-term linseed and lucerne supplementation reduced the antioxidant potential of ostrich meat, especially in L-L45 and L-L55 groups, which was reflected in the highest level of MDA and the lowest activity of SOD. Thus, the optimal results after linseed and lucerne supplementation with regard to ostrich meat oxidative stability were reported in groups L-L65 and L-L75, approximately three to four months prior to slaughter.

  5. Effect of a lucerne feeding strategy in the first week postpartum on feed intake and ketone body profiles in blood plasma, urine, and milk in Holstein cows

    DEFF Research Database (Denmark)

    Larsen, Mogens; Kristensen, Niels Bastian

    2010-01-01

    The objectives were to investigate the effects of a lucerne feeding strategy to postpartum transition dairy cows on feed intake and ketone body profiles in plasma, urine, and milk. At calving, 13 Holstein cows were assigned to one of two treatments: a control lactation diet or a lucerne haylage....... The concentrations of ketone bodies in plasma, urine, and milk tended to be greater at 4 days in milk for lucerne as compared with control. Plasma concentrations of ketone bodies correlated stronger to urinary concentrations than to milk concentrations...

  6. Genetic divergence and association analyses in Hedge lucerne (Desmanthus virgatus L. Willd

    Directory of Open Access Journals (Sweden)

    Deepthi.I.V.L, A. Kalamani and N. Manivannan

    2013-09-01

    Full Text Available Twenty three mutants along with control of hedge lucerne variety TNDV-1 were evaluated for twelve traits to assess genetic divergence. Mutants were grouped in to eight clusters based on D2 values. Based on the inter cluster distances using D2 values, it can be considered that the genotypes belonging to clusters VII and VIII are more diverse. The minimum inter cluster distance was found in clusters II and III indicating their genetic closeness. Cluster VIII which contain single progeny had high mean values for all the characters except for crude fat content. Path analysis revealed that the number of branches per plant, leaf to stem ratio, dry matter yield per plant was considered as important selection indices for green fodder yield per plant.

  7. Medicago PhosphoProtein Database: a repository for Medicago truncatula phosphoprotein data

    Directory of Open Access Journals (Sweden)

    Christopher M. Rose

    2012-06-01

    Full Text Available The ability of legume crops to fix atmospheric nitrogen via a symbiotic association with soil rhizobia makes them an essential component of many agricultural systems. Initiation of this symbiosis requires protein phosphorylation-mediated signaling in response to rhizobial signals named Nod factors. Medicago truncatula (Medicago is the model system for studying legume biology, making the study of its phosphoproteome essential. Here, we describe the Medicago Phosphoprotein Database (http://phospho.medicago.wisc.edu, a repository built to house phosphoprotein, phosphopeptide, and phosphosite data specific to Medicago. Currently, the Medicago Phosphoprotein Database holds 3,457 unique phosphopeptides that contain 3,404 non-redundant sites of phosphorylation on 829 proteins. Through the web-based interface, users are allowed to browse identified proteins or search for proteins of interest. Furthermore, we allow users to conduct BLAST searches of the database using both peptide sequences and phosphorylation motifs as queries. The data contained within the database are available for download to be investigated at the user’s discretion. The Medicago Phosphoprotein Database will be updated continually with novel phosphoprotein and phosphopeptide identifications, with the intent of constructing an unparalleled compendium of large-scale Medicago phosphorylation data.

  8. The influence of compression level and inoculation on biochemical changes in lucerne silages

    Directory of Open Access Journals (Sweden)

    Đorđević Nenad Ž.

    2011-01-01

    Full Text Available The effect of different levels of compression (A1 = 420 gdm-1, A2 = 560 gdm-1 and inoculation (B1 = no inoculant, B2 = with inoculant on changes in chemical composition, proteolysis and quality of lucerne silage was investigated in this paper. Based on the results of chemical analysis we found that in silages with more compressed material there was a reduction in the amount of ammonia nitrogen, soluble nitrogen and acetic acid, and increased content of protein nitrogen (‘true’protein and production of lactic acid (p<0.05. With the inoculation of the ensiling material the production of ammonia nitrogen and acetic acid was reduced but the content of lactic acid and acidity was increased (p<0.05. The interaction of both investigated factors (A×B induced a decrease in the proteolysis degree, increase of lactic acid production and decrease in acetic acid production, and decrease in pH values (p<0.001 in investigated silages. The investigated factors had less influence on the chemical composition of lucerne material, and the significant variations were observed in fat and NFE contents. On the basis of this investigation the degree of compression is the most important parameter in ensiling technology. With the adequate compression and reduction of air in the starting material, the aerobic phase is reduced and the activity of proeolytic enzymes is decreased. In practice the special attention should be given to factors on which directly or indirectly the level of compression of ensiled material depends: wilting, cutting, object selection and/or selection of machines used for compression.

  9. 苜蓿核糖体基因物理定位及染色体荧光分带%Physical Localization of Ribosomal Genes and Chromosome DAPI Banding by in situ Hybridization in Medicago sativa L.

    Institute of Scientific and Technical Information of China (English)

    陈建民; 洪义欢; 王幼平; Steve Bowley; 万建民

    2006-01-01

    利用核糖体基因为探针对,二倍体和四倍体苜蓿(Medicago sativa)进行原位杂交,结果表明,45s在四倍体、二倍体种中总是以单位点位于核仁组织区,5s则有2~3个位点;以二倍体种的基因组DNA为探针的原位杂交表明,蓝花苜蓿(M.coerulea)和黄花苜蓿(M.falcata)均能与四倍体染色体进行杂交,仅杂交信号强弱的染色体数目有差别;荧光染料DAPI使苜蓿的染色体显示带纹,蓝花苜蓿的DAPI带与C-带基本一致.文章对四倍体苜蓿的可能来源进行了讨论.

  10. Mixing sainfoin and lucerne to improve the feed value of legumes fed to sheep by the effect of condensed tannins.

    Science.gov (United States)

    Aufrère, J; Dudilieu, M; Andueza, D; Poncet, C; Baumont, R

    2013-01-01

    The aim of this study was to investigate whether the use of sainfoin-based condensed tannins (CT) enhances feed value when given with tannin-free legumes (lucerne) to sheep. The experiments were conducted with fresh sainfoin and lucerne harvested at two stages (vegetative stage as compared with early flowering) in the first growth cycle. Fresh sainfoin and lucerne forages were combined in ratios of 100 : 0, 75 : 25, 25 : 75 and 0 : 100 (denoted S100, S75, S25 and S0, respectively). Voluntary intake, organic matter digestibility (OMD) and nitrogen (N) retention were measured in sheep fed the different sainfoin and lucerne mixtures. Loss of dry matter (DM) and N from polyester bags suspended in the rumen, abomasum and small intestine (SI) was also measured using rumen-fistulated sheep and intestinally fistulated sheep. The CT content in sainfoin (S100) decreased with increasing percentage of lucerne in the mixture (mean value from 58 g/kg DM for S100 to 18 g/kg DM for S25) and with growth stage (S100: 64 to 52 g/kg DM). OMD did not differ between different sainfoin/lucerne mixture ratios. Sainfoin and lucerne had an associative effect (significant quadratic contrast) on voluntary intake, N intake, total-tract N digestibility, N in faeces and urine (g/g N intake) and N retained (g/g N intake). Compared with lucerne mixtures (S0 and S25), high-sainfoin-content mixtures (S100 and S75) increased the in situ estimates of forage N escaping from the rumen (from 0.162, 0.188 for S0 and S25 to 0.257, 0.287 for S75 and S100) but decreased forage N intestinal digestibility (from 0.496, 0.446 for S0 and S25 to 0.469, 0.335 for S75 and S100). The amount of forage N disappearing from the bags in the SI (per g forage N) was the highest for high-sainfoin mixtures (from 0.082, 0.108 for S100 and S75 to 0.056, 0.058 for S25 and S0, P < 0.001). Rumen juice total N (tN) and ammonia N (NH3-N) values were the lowest in the high-sainfoin diet (mean tN 0.166 mg/g in S100 as compared with 0

  11. Dry matter losses of grass, lucerne and maize silages in bunker silos

    Directory of Open Access Journals (Sweden)

    Brigitte Koehler

    2013-03-01

    Full Text Available An efficient feed management is important for a sustainable and economic agricultural production. One of the main points for improving the efficiency is the reduction of feed losses. In the present investigation the dry matter (DM losses of grass, lucerne and maize silages in farm scaled bunker silos were analysed. The method of determining DM losses was the total-in versus total-out DM mass flow of the silos, including the determination of DM content and other silage parameters via manual sampling. The results taken from 48 silos showed on average for all investigated crops 9–12% of DM losses. Density and feed out rate showed a negative correlation to DM losses in maize silages. According to the applied method for determining DM losses on farm scale, a guideline of 8% can be suggested for maximum DM losses in bunker silos for grass and maize silages. The described method seems to be applicable for improving the feed management by using largely automated measurements on the harvest and feeding side.

  12. Gamma Radiation Effects on some Growth Patterns in Hedge Lucerne (Desmanthus virgatus L.

    Directory of Open Access Journals (Sweden)

    Ameena Premnath, A. Kalamani, C.Babu and G. VijayaKumar

    2010-07-01

    Full Text Available Seeds of Hedge lucerne (Desmanthus virgatus were exposed to different doses (50 to 500 Gys, with an interval of 50 Gysof gamma rays (Cobalt-60 to determine the effectiveness of different doses on growth behaviour and biomasscharacteristics. The lethal dose (LD50 was found to be 250 Gys. About thirty five mutants were identified. High biomassyielding dwarf statured plants were identified from the treatments of 350 and 500 Gys irradiation. Similarly high fodderyielding superior plants as a result of increased number of branches ranging from 22-34 were observed in 400 and 450 Gyspopulation when compared to the control (12-16 branches. Plants of bushy stature with shorter intenodal length (2.25 cmwhen compared to control (3.75 cm were found among the 450 Gys population. Prostrate types were also identified amongthe 50, 350, 400 and 500 Gys population suited for grazing pastures. Based on single plant performance, plants which recordhigh biomass will be identified and M1 seeds will be collected and studied in further generations.

  13. Sustainable development in city districts: BaLaLuZ project - BaBeL Lucerne; Schlussbericht Quartier BaBeL - Phase 1

    Energy Technology Data Exchange (ETDEWEB)

    Duss, A.; Inderbitzin, J.; Wandeler, M.

    2004-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) is one of a series of reports concerning municipal development in various cities in Switzerland. The four city districts involved include Basel (Gundeldinger Feld), Lausanne (Bellevaux), Lucerne (Basel-/Bernstrasse) and Zurich (Werdwies). This final report summarises the results of the first phase of the project concerning the Baselstrasse and Bernstrasse districts in Lucerne. A database containing details of the various buildings in the districts was set up, energy-relevant refurbishment of buildings was investigated, owners were counselled and various diploma-theses for the University of Applied Sciences in Lucerne were initiated. Ecological, economical and mobility aspects are considered and suggestions are made for follow-up projects.

  14. Influence of min-a-zel plus and maize meal addition on the quality of lucerne silage

    Directory of Open Access Journals (Sweden)

    Đorđević Nenad 1

    2004-01-01

    Full Text Available The influence of mineral adsorbent Min-A-Zel Plus (5 g/kg and maize meal (25 and 50 g/kg used alone or combined, on chemical composition, biochemical changes and quality of lucerne silage was investigated. Based on the obtained data, it can be concluded that addition of Min-A-Zel Plus reduces aminogenesis, while the use of maize meal alone or with zeolite favorable conditions are achieved for lactic acid fermentation, so that the quality of obtained silages is better by one quality class. To achieve better effects of silage quality, the use of combination of mineral adsorbent with carbohydrate additives is recommended.

  15. MTGD: The Medicago truncatula genome database.

    Science.gov (United States)

    Krishnakumar, Vivek; Kim, Maria; Rosen, Benjamin D; Karamycheva, Svetlana; Bidwell, Shelby L; Tang, Haibao; Town, Christopher D

    2015-01-01

    Medicago truncatula, a close relative of alfalfa (Medicago sativa), is a model legume used for studying symbiotic nitrogen fixation, mycorrhizal interactions and legume genomics. J. Craig Venter Institute (JCVI; formerly TIGR) has been involved in M. truncatula genome sequencing and annotation since 2002 and has maintained a web-based resource providing data to the community for this entire period. The website (http://www.MedicagoGenome.org) has seen major updates in the past year, where it currently hosts the latest version of the genome (Mt4.0), associated data and legacy project information, presented to users via a rich set of open-source tools. A JBrowse-based genome browser interface exposes tracks for visualization. Mutant gene symbols originally assembled and curated by the Frugoli lab are now hosted at JCVI and tie into our community annotation interface, Medicago EuCAP (to be integrated soon with our implementation of WebApollo). Literature pertinent to M. truncatula is indexed and made searchable via the Textpresso search engine. The site also implements MedicMine, an instance of InterMine that offers interconnectivity with other plant 'mines' such as ThaleMine and PhytoMine, and other model organism databases (MODs). In addition to these new features, we continue to provide keyword- and locus identifier-based searches served via a Chado-backed Tripal Instance, a BLAST search interface and bulk downloads of data sets from the iPlant Data Store (iDS). Finally, we maintain an E-mail helpdesk, facilitated by a JIRA issue tracking system, where we receive and respond to questions about the website and requests for specific data sets from the community.

  16. The Mitochondrial Complexome of Medicago truncatula

    Science.gov (United States)

    Kiirika, Leonard Muriithi; Behrens, Christof; Braun, Hans-Peter; Colditz, Frank

    2013-01-01

    Legumes (Fabaceae, Leguminosae) are unique in their ability to carry out an elaborate endosymbiotic nitrogen fixation process with rhizobia proteobacteria. The symbiotic nitrogen fixation enables the host plants to grow almost independently of any other nitrogen source. Establishment of symbiosis requires adaptations of the host cellular metabolism, here foremost of the energy metabolism mainly taking place in mitochondria. Since the early 1990s, the galegoid legume Medicago truncatula Gaertn. is a well-established model for studying legume biology, but little is known about the protein complement of mitochondria from this species. An initial characterization of the mitochondrial proteome of M. truncatula (Jemalong A17) was published recently. In the frame of this study, mitochondrial protein complexes were characterized using Two-dimensional (2D) Blue native (BN)/SDS-PAGE. From 139 detected spots, the “first hit” (=most abundant) proteins of 59 spots were identified by mass spectrometry. Here, we present a comprehensive analysis of the mitochondrial “complexome” (the “protein complex proteome”) of M. truncatula via 2D BN/SDS-PAGE in combination with highly sensitive MS protein identification. In total, 1,485 proteins were identified within 158 gel spots, representing 467 unique proteins. Data evaluation by the novel GelMap annotation tool allowed recognition of protein complexes of low abundance. Overall, at least 36 mitochondrial protein complexes were found. To our knowledge several of these complexes were described for the first time in Medicago. The data set is accessible under http://www.gelmap.de/medicago/. The mitochondrial protein complex proteomes of Arabidopsis available at http://www.gelmap.de/arabidopsis/ and Medicago are compared. PMID:23596449

  17. MtPAR MYB transcription factor acts as an on switch for proanthocyanidin biosynthesis in Medicago truncatula.

    Science.gov (United States)

    Verdier, Jerome; Zhao, Jian; Torres-Jerez, Ivone; Ge, Shujun; Liu, Chenggang; He, Xianzhi; Mysore, Kirankumar S; Dixon, Richard A; Udvardi, Michael K

    2012-01-31

    MtPAR (Medicago truncatula proanthocyanidin regulator) is an MYB family transcription factor that functions as a key regulator of proanthocyanidin (PA) biosynthesis in the model legume Medicago truncatula. MtPAR expression is confined to the seed coat, the site of PA accumulation. Loss-of-function par mutants contained substantially less PA in the seed coat than the wild type, whereas levels of anthocyanin and other specialized metabolites were normal in the mutants. In contrast, massive accumulation of PAs occurred when MtPAR was expressed ectopically in transformed hairy roots of Medicago. Transcriptome analysis of par mutants and MtPAR-expressing hairy roots, coupled with yeast one-hybrid analysis, revealed that MtPAR positively regulates genes encoding enzymes of the flavonoid-PA pathway via a probable activation of WD40-1. Expression of MtPAR in the forage legume alfalfa (Medicago sativa) resulted in detectable levels of PA in shoots, highlighting the potential of this gene for biotechnological strategies to increase PAs in forage legumes for reduction of pasture bloat in ruminant animals.

  18. Complex patterns of autopolyploid evolution in alfalfa and allies (Medicago sativa; Leguminosae).

    Science.gov (United States)

    Havananda, Tee; Brummer, E Charles; Doyle, Jeff J

    2011-10-01

    Although there is growing evidence that autopolyploidy is a widespread and important evolutionary phenomenon, it has received less attention than allopolyploidy. Medicago sativa comprises several diploid and autopolyploid taxa, including autotetraploid cultivated alfalfa, and affords an opportunity to elucidate the evolutionary history of a morphologically and genetically complex autopolyploid system. Phylogenies and haplotype networks were constructed from two chloroplast noncoding regions (rpl20-rps12 and trnS-trnG spacers) across seven diploid and polyploid infraspecific taxa of M. sativa and five additional closely related Medicago species, and genetic differentiation was estimated. The two most prominent M. sativa autopolyploids have contrasting evolutionary histories. Chloroplast data support a simple autopolyploid origin of subsp. sativa (alfalfa) from diploid subsp. caerulea, from which it is distinguishable in several quantitative characters. In contrast, morphologically identical diploid and autopolyploid cytotypes of subsp. falcata were found to possess very different chloroplast haplotypes, suggesting past introgression from M. prostrata into the polyploid. Despite the presence of hybrids between tetraploid subspecies falcata and sativa, there was little evidence of introgression of chloroplast genomes from either subspecies into the other. Autopolyploid evolution in M. sativa is complicated and has followed very different paths in different subspecific taxa. The potential exists for gene flow in virtually all combinations of subspecies both within and between ploidies, yet despite the existence of hybrids, morphologically and genetically distinctive subspecies persist.

  19. Effect of application rate of commercial lignite-derived amendments on early-stage growth of Medicago sativa and soil health, in acidic soil conditions

    Science.gov (United States)

    Patti, Antonio; Little, Karen; Rose, Michael; Jackson, Roy; Cavagnaro, Tim

    2013-04-01

    Commercially available lignite-derived amendments, sold mainly as humate preparations, have been promoted as plant growth stimulants leading to higher crop yields. These products are also claimed to improve soil properties such as pH. This study investigated the effect of application rate of three lignite-derived amendments on the early-stage growth of a pasture legume, lucerne (Medicago sativa), and soil health in a soil type common to south eastern Australia, in a glasshouse setting. An organic-mineral humate product and 'run of mine' lignite coal did not improve shoot or root growth despite application at a range of rates at, and in excess of, the manufacturers recommendation. Application of soluble K-humate product at 20 kg/ha (9.5 kg/ha C equivalent) produced an observable positive effect in shoot growth. At this application rate, a significant delay in the appearance of chlorotic symptoms was observed along with an increase in soil pH concurrent with decreased availability of soil Mn and Al. Higher root dry weight was associated with lower microbial biomass carbon which may indicate an effect on allocation of resources between the microbial community and the plant. An assessment of the effectiveness of lignite-derived amendments on plant growth, as well as their potential to improve the health of an acidic soil will assist farmers in making decisions regarding the use of these products.

  20. Comparative Analysis of the Symbiotic Efficiency of Medicago truncatula and Medicago sativa under Phosphorus Deficiency

    Directory of Open Access Journals (Sweden)

    Lam-Son Phan Tran

    2013-03-01

    Full Text Available Phosphorus (P-deficiency is a major abiotic stress that limits legume growth in many types of soils. The relationship between Medicago and Sinorhizobium, is known to be affected by different environmental conditions. Recent reports have shown that, in combination with S. meliloti 2011, Medicago truncatula had a lower symbiotic efficiency than Medicago sativa. However, little is known about how Medicago–Sinorhizobium is affected by P-deficiency at the whole-plant level. The objective of the present study was to compare and characterize the symbiotic efficiency of N2 fixation of M. truncatula and M. sativa grown in sand under P-limitation. Under this condition, M. truncatula exhibited a significantly higher rate of N2 fixation. The specific activity of the nodules was much higher in M. truncatula in comparison to M. sativa, partially as a result of an increase in electron allocation to N2 versus H+. Although the main organic acid, succinate, exhibited a strong tendency to decrease under P-deficiency, the more efficient symbiotic ability observed in M. truncatula coincided with an apparent increase in the content of malate in its nodules. Our results indicate that the higher efficiency of the M. truncatula symbiotic system is related to the ability to increase malate content under limited P-conditions.

  1. THE CHARACTERISTICS OF CRUDE PROTEIN AND NDF IN LUCERNE AND MAIZE SILAGES ACCORDING IN SITU AND CNCPS

    Directory of Open Access Journals (Sweden)

    Mária Chrenková

    2012-02-01

    Full Text Available According to Cornell Net Carbohydrate and Protein System (CNCPS and in situ method were determined nutritional characteristics of crude protein (CP in lucerne silage (LS and maize silage (MS. Both LS and MS samples varied highly with concentrations in g.kg-1dry matter (DM: Crude protein (CP 90.6 – 196.0 and 56.0 – 82.5 (P<0.05; neutral detergent fibre (NDF 366.3 – 690.2 and 362.8 – 482.2; acid detergent fibre (ADF 305.7 – 592.9 and 201.7 – 243.2 (P<0.01; acid detergent lignin (ADL 43.7 – 77.2 and 23.8 – 29.2 (P<0.01, respectively. Concentration of B2 was significantly higher in LS than in MS (P<0.05. In situ effective CP degradability (ECPD of LS and MS were similar (75.6 % and 76.3 %. Effective NDF degradability was higher for MS than for LS (36.5 % and 33.2 % but the difference was not significant.

  2. The Medicago truncatula gene expression atlas web server

    Directory of Open Access Journals (Sweden)

    Tang Yuhong

    2009-12-01

    Full Text Available Abstract Background Legumes (Leguminosae or Fabaceae play a major role in agriculture. Transcriptomics studies in the model legume species, Medicago truncatula, are instrumental in helping to formulate hypotheses about the role of legume genes. With the rapid growth of publically available Affymetrix GeneChip Medicago Genome Array GeneChip data from a great range of tissues, cell types, growth conditions, and stress treatments, the legume research community desires an effective bioinformatics system to aid efforts to interpret the Medicago genome through functional genomics. We developed the Medicago truncatula Gene Expression Atlas (MtGEA web server for this purpose. Description The Medicago truncatula Gene Expression Atlas (MtGEA web server is a centralized platform for analyzing the Medicago transcriptome. Currently, the web server hosts gene expression data from 156 Affymetrix GeneChip® Medicago genome arrays in 64 different experiments, covering a broad range of developmental and environmental conditions. The server enables flexible, multifaceted analyses of transcript data and provides a range of additional information about genes, including different types of annotation and links to the genome sequence, which help users formulate hypotheses about gene function. Transcript data can be accessed using Affymetrix probe identification number, DNA sequence, gene name, functional description in natural language, GO and KEGG annotation terms, and InterPro domain number. Transcripts can also be discovered through co-expression or differential expression analysis. Flexible tools to select a subset of experiments and to visualize and compare expression profiles of multiple genes have been implemented. Data can be downloaded, in part or full, in a tabular form compatible with common analytical and visualization software. The web server will be updated on a regular basis to incorporate new gene expression data and genome annotation, and is accessible

  3. [The plant growth-promoting rhizobacterium Arthrobacter agilis UMCV2 endophytically colonizes Medicago truncatula].

    Science.gov (United States)

    Aviles-Garcia, Maria Elizabeth; Flores-Cortez, Idolina; Hernández-Soberano, Christian; Santoyo, Gustavo; Valencia-Cantero, Eduardo

    Arthrobacter agilis UMCV2 is a rhizosphere bacterium that promotes legume growth by solubilization of iron, which is supplied to the plant. A second growth promotion mechanism produces volatile compounds that stimulate iron uptake activities. Additionally, A. agilis UMCV2 is capable of inhibiting the growth of phytopathogens. A combination of quantitative polymerase chain reaction and fluorescence in situ hybridization techniques were used here to detect and quantify the presence of the bacterium in the internal tissues of the legume Medicago truncatula. Our results demonstrate that A. agilis UMCV2 behaves as an endophytic bacterium of M. truncatula, particularly in environments where iron is available. Copyright © 2016 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

  4. Stress responses in alfalfa (Medicago sativa L. )

    Energy Technology Data Exchange (ETDEWEB)

    Kessmann, H.; Edwards, R.; Dixon, R.A. (Samuel Roberts Noble Foundation, Ardmore, OK (USA)); Geno, P.W. (Oklahoma State Univ., Stillwater (USA))

    1990-09-01

    The isoflavonoid conjugates medicarpin-3-O-glucoside-6{double prime}-O-malonate (MGM), afrormosin-7-O-glucoside (AG), and afrormosin-7-O-glucoside-6{double prime}-O-malonate (AGM) were isolated and characterized from cell suspension cultures of alfalfa (Medicago sativa L.), where they were the major constitutive secondary metabolites. They were also found in alfalfa roots but not in other parts of the plant. The phytoalexin medicarpin accumulated rapidly in suspension cultured cells treated with elicitor from Colletotrichum lindemuthianum, and this was subsequently accompanied by an increase in the levels of MGM. In contrast, net accumulation of afrormosin conjugates was not affected by elicitor treatment. Labeling studies with ({sup 14}C)phenylalanine indicated that afrormosin conjugates were the major de novo synthesized isoflavonoid products in unelicited cells. During elicitation, ({sup 14}C)phenylalanine was incorporated predominantly into medicarpin, although a significant proportion of the newly synthesized medicarpin was also conjugated. Treatment of {sup 14}C-labeled, elicited cells with L-{alpha}-aminooxy-{beta}-phenylpropionic acid, a potent inhibitor of PAL activity in vivo, resulted in the initial appearance of labeled medicarpin of very low specific activity, suggesting that the phytoalexin could be released from a preformed conjugate under these conditions. Our data draw attention to the involvement of isoflavone hydroxylases during the constitutive and elicitor-induced accumulation of isoflavonoids and their conjugates in alfalfa cell cultures.

  5. Phenotypical and genotypical characteristics of root-nodulating bacteria isolated from annual Medicago spp. in Soummam Valley (Algeria)

    OpenAIRE

    Sebbane, N.; Sahnoune, M.; Zakhia, Frédéric; Willems, A.; Benallaoua, S.; De Lajudie, Philippe

    2006-01-01

    Aims: In the framework of agro-pastoral system management using local annual medics coupled with their native root-nodulating bacteria to extend pasture zones, increase forage yields and improve ovine and bovine breeding in Algeria, we investigated diversity of rhizobia from annual Medicago spp. (Medicago arabica, Medicago polymorpha, Medicago minima and Medicago orbicularis). Methods and Results: Ten nodulating-isolates were characterized by morphological, cultural, physiological and biochem...

  6. Suicides in the Canton of Lucerne over 5 years: subjects with and without psychiatric history and diagnosis.

    Science.gov (United States)

    Frei, Andreas; Bucher, Toralf; Walter, Marc; Ajdacic-Gross, Vladeta

    2013-03-25

    The majority of suicides had never had contact with the mental health care system. The aim of this study is to investigate the specific characteristics of this particular group. Coroners' files were examined for all 256 suicide victims in the Canton of Lucerne between 2002 and 2006, together with the data from the files of the public psychiatric institutions for individuals who had been registered as patients. The sociodemographic, suicidological and clinical variables of suicides who had been psychiatric patients were compared with those of other suicides. Within the latter group, suicides with remarks on their mental state in the coroner's files ("police diagnosis") were compared with suicides without such remarks. Assisted suicides (24/256 [9.4%]) were excluded from the comparative analysis. 151 (65.1%) of the remaining 232 suicides had never been registered by a public psychiatric service; 40 (26.5%) of these had a "police diagnosis". In the regression analysis intoxication as a suicide method, announcement of suicide and impaired health characterised suicides with an established psychiatric diagnosis, whereas suicides without a psychiatric diagnosis were more likely to be retired. Among the latter, those without a "police diagnosis" were more likely to have left a suicide note. Unexpectedly, the only difference between suicide methods with and without former contact with the mental health system was poisoning. Within the latter group, the subgroup without "police diagnosis" left more suicide notes. Further qualitative analyses of suicide notes might be useful in improving understanding of the motives of suicides without a manifest psychiatric history.

  7. Local to regional scale industrial heavy metal pollution recorded in sediments of large freshwater lakes in central Europe (lakes Geneva and Lucerne) over the last centuries.

    Science.gov (United States)

    Thevenon, Florian; Graham, Neil D; Chiaradia, Massimo; Arpagaus, Philippe; Wildi, Walter; Poté, John

    2011-12-15

    This research first focuses on the spatial and temporal patterns of heavy metals from contrasting environments (highly polluted to deepwater sites) of Lake Geneva. The mercury (Hg) and lead (Pb) records from two deepwater sites show that the heavy metal variations before the industrial period are primarily linked to natural weathering input of trace elements. By opposition, the discharge of industrial treated wastewaters into Vidy Bay of Lake Geneva during the second part of the 20th century, involved the sedimentation of highly metal-contaminated sediments in the area surrounding the WWTP outlet pipe discharge. Eventually, a new Pb isotope record of sediments from Lake Lucerne identifies the long-term increasing anthropogenic lead pollution after ca. 1500, probably due to the development of metallurgical activities during the High Middle Ages. These data furthermore allows to compare the recent anthropogenic sources of water pollution from three of the largest freshwater lakes of Western Europe (lakes Geneva, Lucerne, and Constance). High increases in Pb and Hg highlight the regional impact of industrial pollution after ca. 1750-1850, and the decrease of metal pollution in the 1980s due to the effects of remediation strategies such as the implementation of wastewater treatment plants (WWTPs). However, at all the studied sites, the recent metal concentrations remain higher than pre-industrial levels. Moreover, the local scale pollution data reveal two highly contaminated sites (>100 μg Pb/g dry weight sediment) by industrial activities, during the late-19th and early-20th centuries (Lake Lucerne) and during the second part of the 20th century (Vidy Bay of Lake Geneva). Overall, the regional scale pollution history inferred from the three large and deep perialpine lakes points out at the pollution of water systems by heavy metals during the last two centuries due to the discharge of industrial effluents.

  8. Transfer of anthracnose resistance and pod coiling traits from Medicago arborea to M. sativa by sexual reproduction.

    Science.gov (United States)

    Armour, D J; Mackie, J M; Musial, J M; Irwin, J A G

    2008-07-01

    Five asymmetric hybrid plants were obtained between Medicago sativa (2n = 4x = 32) and Medicago arborea (2n = 4x = 32) through sexual reproduction and the use of a cytoplasmically male sterile M. sativa genotype. Over 2,000 pollinations were made to obtain these hybrids. Amplified fragment length polymorphism (AFLP) analysis showed that in the most studied hybrid (WA2273), 4% of the bands unique to the M. arborea parent were present, versus 72% for the unique M. sativa bands. This suggests that only a single M. arborea chromosome or chromosome parts has been transferred. WA2273 had 7% of AFLP bands which were not present in either parent, which is suggestive of chromosome rearrangements as would be expected if only chromosome parts or a single part had been transferred from M. arborea. Phenotypic evidence for hybridity was obtained for pod coiling (1.4 coils in WA2273 versus three coils in the M. sativa parent and its self and testcross populations, and one coil in M. arborea), and Colletotrichum trifolii race 2 resistance (transferred from the resistant M. arborea parent, as the M. sativa parent and the self populations were highly susceptible). The hybrids were self sterile, but were female fertile to a high level when crossed with 4x, but not 2x, M. sativa, indicating they were at or near 4x. Both the pod coiling trait and anthracnose resistance segregated in the progeny of testcrosses between WA2273 and M. sativa. The work demonstrates that agronomically useful traits can be introgressed into M. sativa from M. arborea by use of male sterile M. sativa and sexual reproduction.

  9. Replication and encapsidation of the viroid-like satellite RNA of lucerne transient streak virus are supported in divergent hosts by cocksfoot mottle virus and turnip rosette virus.

    Science.gov (United States)

    Sehgal, O P; Sinha, R C; Gellatly, D L; Ivanov, I; AbouHaidar, M G

    1993-04-01

    Cocksfoot mottle sobemovirus supports replication and encapsidation of the viroid-like satellite RNA (sat-RNA) of lucerne transient streak virus (LTSV) in two monocotyledonous species, Triticum aestivum and Dactylis glomerata. Additionally, LTSV sat-RNA replicates effectively in the presence of turnip rosette sobemovirus in Brassica rapa, Raphanus raphanistrum and Sinapsis arvensis, but not in Thlaspi arvense or Nicotiana bigelovii, indicating that host species markedly influence this interaction. Previous reports of the association between LTSV sat-RNA and helper sobemoviruses were limited to dicotyledonous hosts. Our results demonstrate that the biological interaction between these two entities spans divergent dicotyledonous and monocotyledonous species.

  10. Effects of dehydrated lucerne and soya bean meal on milk production and composition, nutrient digestion, and methane and nitrogen losses in dairy cows receiving two different forages.

    Science.gov (United States)

    Doreau, M; Ferlay, A; Rochette, Y; Martin, C

    2014-03-01

    Dehydrated lucerne is used as a protein source in dairy cow rations, but little is known about the effects of lucerne on greenhouse gas production by animals. Eight Holstein dairy cows (average weight: 582 kg) were used in a replicated 4 × 4 Latin square design. They received diets based on either maize silage (M) or grass silage (G) (45% of diet on dry matter (DM) basis), with either soya bean meal (15% of diet DM) completed with beet pulp (15% of diet DM) (SP) or dehydrated lucerne (L) (30% of diet DM) as protein sources; MSP, ML, GSP and GL diets were calculated to meet energy requirements for milk production by dairy cows and degradable protein for rumen microbes. Dry matter intake (DMI) did not differ among diets (18.0 kg/day DMI); milk production was higher with SP diets than with L diets (26.0 v. 24.1 kg/day), but milk production did not vary with forage type. Milk fatty-acid (FA) composition was modified by both forage and protein sources: L and G diets resulted in less saturated FA, less linoleic acid, more trans-monounsaturated FA, and more linolenic acid than SP and M diets, respectively. Enteric methane (CH4) production, measured by the SF6 tracer method, was higher for G diets than for M diets, but did not differ with protein source. The same effects were observed when CH4 was expressed per kg milk. Minor effects of diets on rumen fermentation pattern were observed. Manure CH4 emissions estimated from faecal organic matter were negatively related to diet digestibility and were thus higher for L than SP diets, and higher for M than G diets; the resulting difference in total CH4 production was small. Owing to diet formulation constraints, N intake was higher for SP than for L diets; interaction between forage type and protein source was significant for N intake. The same statistical effects were found for N in milk. Faecal and urinary N losses were determined from total faeces and urine collection. Faecal N output was lower for M than for G diets but

  11. The effect of varying proportion and chop length of lucerne silage in a maize silage-based total mixed ration on diet digestibility and milk yield in dairy cattle.

    Science.gov (United States)

    Thomson, A L; Humphries, D J; Jones, A K; Reynolds, C K

    2017-06-27

    The objective was to assess the effects of inclusion rate and chop length of lucerne silage, when fed in a total mixed ration (TMR), on milk yield, dry matter (DM) intake (DMI) and digestion in dairy cows. Diets were formulated to contain a 50 : 50 ratio of forage : concentrate (DM basis) and to be isonitrogenous (170 g/kg CP). The forage portion of the offered diets was comprised of maize and lucerne silage in proportions (DM basis) of either 25 : 75 (high Lucerne (HL)) or 75 : 25 (low lucerne (LL)). Lucerne was harvested and conserved as silage at either a long (L) or short (S) chop length. These variables were combined in a 2×2 factorial arrangement to give four treatments (HLL, HLS, LLL, LLS) which were fed in a Latin square design study to Holstein dairy cows in two separate experiments. In total, 16 and 8 multiparous, mid-lactation cows were used in experiments 1 and 2, respectively. To ensure sufficient silage for both experiments, different cuts of lucerne silage (taken from the same sward) were used for each experiment: first cut for experiment 1 (which was of poorer quality) and second cut for experiment 2. Dry matter intake, milk yield and milk composition where measured in both experiments, and total tract digestibility and nitrogen (N) balance were assessed using four cows in experiment 2. In experiment 1, cows fed LL had increased DMI (+3.2 kg/day), compared with those fed HL. In contrast, there was no difference in DMI due to lucerne silage inclusion rate in experiment 2. A reduction in milk yield was observed with the HL treatment in both experiment 1 and 2 (-3.0 and -2.9 kg/day, respectively). The HL diet had reduced digestibility of DM and organic matter (OM) (-3% and -4%, respectively), and also reduced the efficiency of intake N conversion into milk N (-4%). The S chop length increased total tract digestibility of DM and OM (both +4%), regardless of inclusion rate. Inclusion of lucerne silage at 25% of forage DM increased milk yield relative to

  12. Root developmental programs shape the Medicago truncatula nodule meristem

    NARCIS (Netherlands)

    Franssen, H.; Xiao, T.T.; Kulikova, O.; Wan, X.; Bisseling, T.; Scheres, B.; Heidstra, R.

    2015-01-01

    Nodules on the roots of legume plants host nitrogen-fixing Rhizobium bacteria. Several lines of evidence indicate that nodules are evolutionarily related to roots. We determined whether developmental control of the Medicago truncatula nodule meristem bears resemblance to that in root meristems

  13. Comparison of the phytoremediation potentials of Medicago falcata L. And Medicago sativa L. in aged oil-sludge-contaminated soil.

    Science.gov (United States)

    Panchenko, Leonid; Muratova, Anna; Turkovskaya, Olga

    2017-01-01

    Thirteen-year monitoring of the vegetation growing in the industrial and adjacent areas of an oil refinery showed the prevalence of yellow medick (Medicago falcata L.) over other plant species, including alfalfa (Medicago sativa L.). A comparative field study of the two Medicago species established that yellow medick and alfalfa exhibited similar resistance to soil petroleum hydrocarbons and that the pollutant concentration in their rhizosphere was 30% lower than that in the surrounding bulk soil. In laboratory pot experiments, yellow medick reduced the contaminant content by 18% owing to the degradation of the major heavy oil fractions, such as paraffins, naphthenes, and alcohol and benzene tars; and it was more successful than alfalfa. Both species were equally effective in stimulating the total number of soil microorganisms, but the number of hydrocarbon-oxidizing microorganisms, including polycyclic aromatic hydrocarbon degraders, was larger in the root zone of alfalfa. In turn, yellow medick provided a favorable balance of available nitrogen. Both Medicago species equally stimulated the dehydrogenase and peroxidase activities of the soil, and yellow medick increased the activity of soil polyphenol oxidase but reduced the activity of catalase. The root tissue activity of catalase, ascorbate oxidase, and tyrosinase was grater in alfalfa than in yellow medick. The peroxidase activity of plant roots was similar in both species, but nondenaturing polyacrylamide gel electrophoresis showed some differences in the peroxidase profiles of the root extracts of alfalfa and yellow medick. Overall, this study suggests that the phytoremediation potentials of yellow medick and alfalfa are similar, with some differences.

  14. Definition and evolution of a new symbiovar, sv. rigiduloides, among Ensifer meliloti efficiently nodulating Medicago species.

    Science.gov (United States)

    Gubry-Rangin, Cécile; Béna, Gilles; Cleyet-Marel, Jean-Claude; Brunel, Brigitte

    2013-10-01

    Understanding functional diversity is one of the main goals of microbial ecology, and definition of new bacterial ecotypes contributes significantly to this objective. Nitrogen-fixing bacteria provide a good system for investigation of ecotypes/biovars/symbiovars, as they present different specific associations with several host plants. This specific symbiosis is reflected both in the nodulation and fixation efficiency and in genetic characters of the bacteria, and several biovars have already been described in the bacterial species Ensifer meliloti. In the present study, the species affiliation of E. meliloti strains trapped from nodules sampled from Medicago rigiduloïdes roots was analyzed using housekeeping recA genes and DNA-DNA hybridization. The genetic diversity of these isolates was also investigated using several symbiotic markers: nodulation (nodA, nodB, nodC) and nitrogen fixation (nifH) genes, as well as the performance of phenotypic tests of nodulation capacity and nitrogen fixation efficiency. These analyses led to the proposal of a new bacterial symbiovar, E. meliloti sv. rigiduloides, that fixed nitrogen efficiently on M. rigiduloïdes, but not on Medicago truncatula. Using phylogenetic reconstructions, including the different described symbiovars, several hypotheses of lateral gene transfer and gene loss are proposed to explain the emergence of symbiovars within this species. The widespread geographical distribution of this symbiovar around the Mediterranean Basin, in contrast to restriction of M. rigiduloïdes to Eastern European countries, suggests that these isolates might also be associated with other plant species. The description of a new symbiovar within E. meliloti confirms the need for accurate bacterial ecological classification, especially for analysis of bacterial populations.

  15. Effect of seed mixture composition and management on competitiveness of herbs in temporary grasslands

    DEFF Research Database (Denmark)

    Mortensen, Tine Bloch; Søegaard, Karen; Eriksen, Jørgen

    2012-01-01

    (Carum carvi), birdsfoot trefoil (Lotus corniculatus), chervil (Anthriscus cerefolium), plantain (Plantago lanceolata), lucerne (Medicago sativa), and melilot (Melilotus officinalis). All herb species, except lucerne and caraway, were most competitive in the first harvest year. The proportion of all...

  16. Sinorhizobium meliloti can protect Medicago truncatula against Phoma medicaginis attack

    Directory of Open Access Journals (Sweden)

    Moncef MRABET

    2011-09-01

    Full Text Available The Sinorhizobium meliloti microsymbiont of Medicago spp. was used in an antibiosis test against Phoma medicaginis and in bioprotection assays of Medicago truncatula JA17 from the pathogen. Among 17 S. meliloti strains isolated from root nodules of M. truncatula and Medicago laciniata grown in Tunisian soils, six showed up to 60% growth inhibition of five P. medicaginis strains isolated from infected field-grown M. truncatula. Two S. meliloti strains with differing in vitro effects on P. medicaginis, 10.16/R6 antagonist and 5M6 non antagonist, were used in a bioprotection assay of M. truncatula JA17 from the pathogen. The inoculation of P. medicaginis caused complete root and stem rotting, and the mortality of all treated plantlets. Inoculation of the antagonist S. meliloti strain 10.16/R6 to M. truncatula JA17 infected with P. medicaginis was associated with a significant 65% decrease of vegetative rotting length, an 80% decrease of plant mortality, an increase of root length, and enhancement of root and shoot biomass comparatively to control plantlets treated with P. medicaginis. The inoculation of the non antagonistic S. meliloti strain 5M6 slightly decreased disease and slightly increased plant growth parameters.

  17. Intrusive rocks of the Holden and Lucerne quadrangles, Washington; the relation of depth zones, composition, textures, and emplacement of plutons

    Science.gov (United States)

    Cater, Fred W.

    1982-01-01

    The core of the northern Cascade Range in Washington consists of Precambrian and upper Paleozoic metamorphic rocks cut by numerous plutons, ranging in age from early Triassic to Miocene. The older plutons have been eroded to catazonal depths, whereas subvolcanic rocks are exposed in the youngest plutons. The Holden and Lucerne quadrangles span a -sizeable and representative part of this core. The oldest of the formations mapped in these quadrangles is the Swakane Biotite Gneiss, which was shown on the quadrangle maps as Cretaceous and older in age. The Swakane has yielded a middle Paleozoic metamorphic age, and also contains evidence of zircon inherited from some parent material more than 1,650 m.y. old. In this report, the Swakane is assigned an early Paleozoic or older age. It consists mostly of biotite gneiss, but interlayered with it are scattered layers and lenses of hornblende schist and gneiss, clinozoisite-epidote gneiss, and quartzite. Thickness of the Swakane is many thousands of meters, and the base is not exposed. The biotite gneiss is probably derived from a pile of siliceous volcanic rocks containing scattered sedimentary beds and basalt flows. Overlying the Swakane is a thick sequence of eugeosynclinal upper Paleozoic rocks metamorphosed to amphibolite grade. The sequence includes quartzite and thin layers of marble, hornblende schist and gneiss, graphitic schist, and smaller amounts of schist and gneiss of widely varying compositions. The layers have been tightly and complexly folded, and, in places, probably had been thrust over the overlying Swakane prior to metamorphism. Youngest of the supracrustal rocks in the area are shale, arkosic sandstone, and conglomerate of the Paleocene Swauk Formation. These rocks are preserved in the Chiwaukum graben, a major structural element of the region. Of uncertain age, but possibly as old as any of the intrusive rocks in the area, are small masses of ultramafic rocks, now almost completely altered to

  18. Sexual Polyploidization in Medicago sativa L.: Impact on the Phenotype, Gene Transcription, and Genome Methylation

    Directory of Open Access Journals (Sweden)

    Daniele Rosellini

    2016-04-01

    Full Text Available Polyploidization as the consequence of 2n gamete formation is a prominent mechanism in plant evolution. Studying its effects on the genome, and on genome expression, has both basic and applied interest. We crossed two diploid (2n = 2x = 16 Medicago sativa plants, a subsp. falcata seed parent, and a coerulea × falcata pollen parent that form a mixture of n and 2n eggs and pollen, respectively. Such a cross produced full-sib diploid and tetraploid (2n = 4x = 32 hybrids, the latter being the result of bilateral sexual polyploidization (BSP. These unique materials allowed us to investigate the effects of BSP, and to separate the effect of intraspecific hybridization from those of polyploidization by comparing 2x with 4x full sib progeny plants. Simple sequence repeat marker segregation demonstrated tetrasomic inheritance for all chromosomes but one, demonstrating that these neotetraploids are true autotetraploids. BSP brought about increased biomass, earlier flowering, higher seed set and weight, and larger leaves with larger cells. Microarray analyses with M. truncatula gene chips showed that several hundred genes, related to diverse metabolic functions, changed their expression level as a consequence of polyploidization. In addition, cytosine methylation increased in 2x, but not in 4x, hybrids. Our results indicate that sexual polyploidization induces significant transcriptional novelty, possibly mediated in part by DNA methylation, and phenotypic novelty that could underpin improved adaptation and reproductive success of tetraploid M. sativa with respect to its diploid progenitor. These polyploidy-induced changes may have promoted the adoption of tetraploid alfalfa in agriculture.

  19. Cloning and characterization of a heat shock protein 70 gene, MsHSP70-1, in Medicago sativa

    Institute of Scientific and Technical Information of China (English)

    Zhishui He; Rong Xie; Yanzhang Wang; Huasong Zou; Jiabi Zhu; Guanqiao Yu

    2008-01-01

    Some members of the heat shock protein 70 (HSP70) family have important functions in organism development. Here, we identified an alfalfa (Medicago sativa L. cv. Algonquin) HSP70 gene, MsHSP70-1, using cDNA array and reverse transcription-polymerase chain reaction. This gene contains a 1947 bp open reading frame encoding a protein of 649 amino acids.This protein contains all conserved domains,motifs.and characteristic sequences of plant HSP70s.The expression of MsHsP70-1 is enhanced in nodule compared withroot,stem,leaf,and flower,and throughout the process of nodule development.Northern hybridization analysis indicated that the expression of MsHSP70-1 in nodule requires the active bacA gene of rhizobia.These results suggested that MsHSP70-1 might play an important role in alfalfa nodule development.

  20. Evaluation of ensilage potential of alfalfa cultivars (Medicago sativa L.)

    OpenAIRE

    Monteiro, ALG; Costa,Ciniro; Arrigoni, M. D.

    1998-01-01

    The objective of this trial was to study the ensilage potential of alfalfa (Medicago sativa L,.). The material used in the evaluation was harvested from an experiment in a complete randomized blocks design with three replicates, with seventeen alfalfa cultivars, Criouil, Florida 77, P555, P581, Moapa, Gilboa, 34 Linea, C/W 8754, C/W 4468, C/W 86, C/W 8746, Hunter Field, Trifecta, Sequel, CUF 101, Aurora e Siriver, during three years. The harvest used for the determinations was collected at 30...

  1. Sustainable development in city districts: BaLaLuZ project. Final report phase 2. BaBeL Lucerne; Nachhaltige Quartierentwicklung BaLaLuZh. Schlussbericht Phase 2. Quartier BaBeL

    Energy Technology Data Exchange (ETDEWEB)

    Wandeler, M.; Inderbitzin, J. [Babel, Lucerne (Switzerland); Geissbuehler, D. [Hochschule fuer Technik und Architektur (HTA) Luzern, Horw (Switzerland)

    2006-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) is one of a series of reports concerning municipal development in various cities in Switzerland. The four city districts involved include Basel (Gundeldinger Feld), Lausanne (Bellevaux), Lucerne (Basel-/Bernstrasse) and Zurich (Werdwies). This final report summarises the results of the second phase of the project concerning the Baselstrasse and Bernstrasse districts in Lucerne. Alongside the planned work, a planning instrument that aids co-ordination and know-how-transfer was developed in this second phase. This master plan and the organisational structure for 2006 is described. Application work to be done from 2007 onwards is looked at. The main part of this report consists of eight annexes that define and describe building blocks for measures to be taken, the master plan, a plan of action 2007 - 2009, along with organisational and financial data.

  2. A new approach to direct somatic embryogenesis in Medicago.

    Science.gov (United States)

    Denchev, P; Velcheva, M; Atanassov, A

    1991-09-01

    A highly efficient system for direct somatic embryogenesis is described. Leaf sections originating from young trifoliate leaves of Medicago falcata line 47/1-5 and Medicago sativa line No2/9R, directly produced embryos after cultivation in liquid B5IV induction medium. In comparison with indirect somatic embryogenesis the system omits the callus stage and thus allows shortening of the process of somatic embryogenesis in alfalfa by 35-40 days. It permits the avoidance of secondary changes occurring during the process of dedifferentiation. A modified B5/3H medium containing Polyethylene Glycol 6000 promoted embryo development from globular up to torpedo stage. It was clearly shown that 2.5% Polyethylene Glycol stimulated this process for both H. falcata 47/1-5 and M. sativa No 2/9R. Maturation of torpedo stage embryos was carried out on solidified or liquid abscisic acidcontaining medium. A 30μM abscisic acid concentration was optimal in allowing one embryo to yield one plant. Somatic embryo conversion to plants and plant regeneration was performed on Murashige and Skoog medium. Regenerated plants showed a normal morphology.

  3. Isolation and functional characterization of salt-stress induced RCI2-like genes from Medicago sativa and Medicago truncatula.

    Science.gov (United States)

    Long, Ruicai; Zhang, Fan; Li, Zhenyi; Li, Mingna; Cong, Lili; Kang, Junmei; Zhang, Tiejun; Zhao, Zhongxiang; Sun, Yan; Yang, Qingchuan

    2015-07-01

    Salt stress is one of the most significant adverse abiotic factors, causing crop failure worldwide. So far, a number of salt stress-induced genes, and genes improving salt tolerance have been characterized in a range of plants. Here, we report the isolation and characterization of a salt stress-induced Medicago sativa (alfalfa) gene (MsRCI2A), which showed a high similarity to the yeast plasma membrane protein 3 gene (PMP3) and Arabidopsis RCI2A. The sequence comparisons revealed that five genes of MtRCI2(A-E) showed a high similarity to MsRCI2A in the Medicago truncatula genome. MsRCI2A and MtRCI2(A-E) encode small, highly hydrophobic proteins containing two putative transmembrane domains, predominantly localized in the plasma membrane. The transcript analysis results suggest that MsRCI2A and MtRCI2(A-D) genes are highly induced by salt stress. The expression of MsRCI2A and MtRCI2(A-C) in yeast mutants lacking the PMP3 gene can functionally complement the salt sensitivity phenotype resulting from PMP3 deletion. Overexpression of MsRCI2A in Arabidopsis plants showed improved salt tolerance suggesting the important role of MsRCI2A in salt stress tolerance in alfalfa.

  4. Three way interactions between Thymus vulgaris, Medicago truncatula and Sinorhizobium meliloti

    OpenAIRE

    Grøndahl, Eva; Ehlers, Bodil Kirstine

    2012-01-01

    Thymus vulgaris is a dominating component of the Mediterranean garrigue vegetation. It produces aromatic oil, containing monoterpenes, which affects the performance (growth, survival) of other plants, and microorganisms. Annual plant species of the genus Medicago are commonly found in Mediterranean thyme communities; in fact they often grow very close to thyme plants (within 1 square meter). Medicago has a symbiosis with the nitrogen fixing bacteria Sinorhizobium meliloti – which is essential...

  5. Medicago truncatula Rop GTPases expression in young nodules

    Directory of Open Access Journals (Sweden)

    Lucia Kusu

    2012-02-01

    Full Text Available Small GTPases are monomeric guanine nucleotide binding proteins with molecular weight of 21 to 30 kD. Plants have plantspecific small GTPases, termed Rop (Rho GTPases from plants which serve as signaling proteins in plant signal transduction. To have better understanding on nodulation process in legume, which Rop proteins that play a dominant role in nodule formation would be determined. Therefore, the expression of five Medicago truncatula Rop GTPase genes (MtRops in young nodules were studied in this experiment. RT-PCR method was used to examine the expression of MtRops. The MtRops expression in inoculated M. truncatula plants were compared with those in uninoculated plants. Results of this studies showed that the expression of MtRop5 and MtRop6 were significantly induced in young nodules, it was suggesting that these Rops may have important role during nodule formation.

  6. Crystal structure of isoflavone reductase from alfalfa (Medicago sativa L.).

    Science.gov (United States)

    Wang, Xiaoqiang; He, Xianzhi; Lin, Jianqiao; Shao, Hui; Chang, Zhenzhan; Dixon, Richard A

    2006-05-19

    Isoflavonoids play important roles in plant defense and exhibit a range of mammalian health-promoting activities. Isoflavone reductase (IFR) specifically recognizes isoflavones and catalyzes a stereospecific NADPH-dependent reduction to (3R)-isoflavanone. The crystal structure of Medicago sativa IFR with deletion of residues 39-47 has been determined at 1.6A resolution. Structural analysis, molecular modeling and docking, and comparison with the structures of other NADPH-dependent enzymes, defined the putative binding sites for co-factor and substrate and potential key residues for enzyme activity and substrate specificity. Further mutagenesis has confirmed the role of Lys144 as a catalytic residue. This study provides a structural basis for understanding the enzymatic mechanism and substrate specificity of IFRs as well as the functions of IFR-like proteins.

  7. [Quality standard of uygur medicine Medicago sativa seeds].

    Science.gov (United States)

    Ding, Wen-Huan; Xu, Hai-Yan; Wang, Dong-Dong; Li, Jie; Tian, Shu-Ge

    2013-11-01

    In this paper, microscopic identification method was adopted to observe the microscopic characters of ten batches of Medicago sativa seeds. And M. sativa seeds were identificated by TLC method in contrast to trigonelline and stachydrine hydrochloride. The impurities, moisture, ash, sour insoluble ash were detected based on Chinese Pharmacopoeia 2010 version (Vol I ). An HPLC method was also established for determination of trigonelline in the M. sativa seeds. The contents of impurities, moisture, ash, sour insoluble ash should not exceed 5%, 10%, 6%, and 2%, respectively. The content of trigonelline should be not less than 0.795 6 mg x g(-1). The experimental methods were accurate and reliable, and can be used as the quality control of the seeds of M. sativa.

  8. Immature seeds and embryos of Medicago truncatula cultured in vitro.

    Science.gov (United States)

    Ochatt, Sergio J

    2011-01-01

    Legumes are an important source of proteins and lipids for food and feed. In addition, they are -environmentally friendly because of their capacity to fix nitrogen through a symbiosis with Rhizobium that permits them to produce abundant proteins even in the absence of nitrogen fertilization. Seed development in plants follows three chronological steps (1) seed coat differentiation, embryo morphogenesis and endosperm development; (2) embryo maturation with storage accumulation and (3) dehydration and the acquisition of desiccation tolerance. Finally, germination occurs when the environmental conditions become favourable. Working with the model legume Medicago truncatula, an in vitro protocol was developed for the culture of immature embryos that permits their development in a way comparable to that observed in plants.In this chapter, the usefulness of this system for investigating embryo development in legumes is outlined.

  9. The efficiency of nitrogen fixation of the model legume Medicago truncatula (Jemalong A17) is low compared to Medicago sativa.

    Science.gov (United States)

    Sulieman, Saad; Schulze, Joachim

    2010-06-15

    Medicago truncatula (Gaertn.) (barrel medic) serves as a model legume in plant biology. Numerous studies have addressed molecular aspects of the biology of M. truncatula, while comparatively little is known about the efficiency of N(2) fixation at the whole plant level. The objective of the present study was to compare the efficiency of N(2) fixation of M. truncatula to the genetically closely related Medicago sativa (L.) (alfalfa). The relative growth of both species relying exclusively on N(2) fixation versus nitrate nutrition, H(2) evolution, nitrogen assimilation, the concentration of amino acids and organic acids in nodules, and (15)N(2) uptake and distribution were studied. M. truncatula showed much lower efficiency of N(2) fixation. Nodule-specific activity was several-fold lower when compared to M. sativa, partially as a result of a lower electron allocation to N(2) versus H(+). M. truncatula or M. sativa plants grown solely on N(2) fixation as a nitrogen source reached about 30% or 80% of growth, respectively, when compared to plants supplied with sufficient nitrate. Moreover, M. truncatula had low %N in shoots and a lower allocation of (15)N to shoots during 1h (15)N(2) labeling period. Amino acid concentration was about 20% higher in M. sativa nodules, largely as a result of more asparagine, while the organic acid concentration was about double in M. sativa, coinciding with a six-fold higher concentration of malate. Total soluble protein in nodules was about three times lower in M. truncatula and the pattern of enzyme activity in that fraction was strongly different. Sucrose cleaving enzymes displayed higher activity in M. truncatula nodules, while the activity of phosphoenolpyruvate carboxylase (PEPC) was much lower. It is concluded that the low efficiency of the M. truncatula symbiotic system is related to a low capacity of organic acid formation and limited nitrogen export from nodules.

  10. Cloning and characterization of chromosomal markers in alfalfa (Medicago sativa L.).

    Science.gov (United States)

    Yu, Feng; Lei, Yunting; Li, Yuan; Dou, Quanwen; Wang, Haiqing; Chen, Zhiguo

    2013-07-01

    Eleven tandemly repetitive sequences were identified from a Cot-1 library by FISH and sequence analysis of alfalfa (Medicago sativa). Five repetitive sequences (MsCR-1, MsCR-2, MsCR-3, MsCR-4, and MsCR-5) were centromeric or pericentromeric, of which three were satellite DNAs and two were minisatellite DNAs. Monomers of 144, 148, and 168 bp were identified in MsCR-1, MsCR-2, and MsCR-3, respectively, while 15 and 39 bp monomers were identified in MsCR-4 and MsCR-5, respectively. Three repetitive sequences were characterized as subtelomeric; one repetitive sequence, MsTR-1, had a 184 bp monomer, and two repetitive sequences had fragments of 204 and 327 bp. Sequence analysis revealed homology (70-80 %) between MsTR-1 and a highly repeated sequence (C300) isolated from M. ssp. caerulea. Three identified repetitive sequences produced hybridization signals at multiple sites in a few of the chromosomes; one repetitive sequence was identified as the E180 satellite DNA previously isolated from M. sativa, while the other 163 and 227 bp fragments had distinct sequences. Physical mapping of the repetitive sequences with double-target FISH revealed different patterns. Thus, nine novel tandemly repetitive sequences that can be adopted as distinct chromosome markers in alfalfa were identified in this study. Furthermore, the chromosome distribution of each sequence was well described. Though significant chromosome variations were detected within and between cultivars, a molecular karyotype of alfalfa was suggested with the chromosome markers we identified. Therefore, these novel chromosome markers will still be a powerful tool for genome composition analysis, phylogenetic studies, and breeding applications.

  11. Ectopic Expression of a Phytase Gene from Medicago truncatula Barrel Medic Enhances Phosphorus Absorption in Plants

    Institute of Scientific and Technical Information of China (English)

    Kai Xiao; Jian-Heng Zhang; Maria Harrison; Zeng-Yu Wang

    2006-01-01

    In the present study, the phosphorus-absorption capacity of transgenic Arabidopsis plants ectopically expressing a novel phytase gene from Medicago truncatula Barrel Medic was evaluated. A full-length cDNA encoding an extracellular form of phytase was isolated from the model legume M. truncatula. The phytase gene (MtPHY1) has an open reading frame of 1 632 bp predicted to encode 543 amino acids, including an Nterminal signal peptide of 27 amino acids. The genomic sequence of the MtPHY1 gene is 5 151 bp, containing seven exons interrupted by six introns. Under high-Pi (2 mmol/L) growth conditions, higher levels of MtPHY1transcripts accumulated in the leaf and stem than in the root. The transcript level was reduced in the stem and increased in the root, with no obvious changes in the hybridization signal detected in the leaf under lowPi (10 μmol/L) conditions. Chimeric transgenes were constructed by placing MtPHY1 under the control of the constitutive CaMV35S promoter and the root-specific MtPT1 promoter. Phytase activities in root apoplast of transgenic Arabidopsis were 12.3- to 16.2-fold of that in control plants. The phytase expressed was secreted into the rhizosphere, as demonstrated by HPLC analysis of phytate degradation by root exudates. Ectopic expression of MtPHY1 in Arabidopsis, leading to significant improvement in organic phosphorus absorption and plant growth, indicated that MtPHY1 has great potential for improving plant phosphorus absorption and phytoremediation.

  12. Temporal effects on the composition of a population of Sinorhizobium meliloti associated with Medicago sativa and Melilotus alba.

    Science.gov (United States)

    Bromfield, E S; Butler, G; Barran, L R

    2001-06-01

    An assessment was made of the impact of temporal separation on the composition of a population of Sinorhizobium meliloti associated with Medicago sativa (alfalfa) and Melilotus alba (sweet clover) grown at a single site that had no known history of alfalfa cultivation. Root nodules were sampled on six occasions over two seasons, and a total of 1620 isolates of S. meliloti were characterized on the basis of phage sensitivity using 16 typing phages. Plant infection tests indicated that symbiotic S. meliloti were deficient in the soil at the time of planting and that these bacteria were present at low density during the first season (<10(2)/g of soil); in the second season numbers increased markedly to about 10(5)/g of soil. Overall, 37 and 51 phage types, respectively, were encountered among the nodule isolates from M. sativa and M. alba. The data indicate significant temporal shifts in the frequency and diversity of types associated with the two legume species. Apparent temporal variation with respect to the frequency of types appeared largely unpredictable and was not attributable to any one sampling time. The results indicate an apparent reduction in phenotypic diversity over the course of the experiment. Differential host plant selection of specific types with respect to nodule occupancy was indicated by significant interactions between legume species and either the frequency or diversity of phage types. Isolates from M. sativa that were resistant to lysis by all typing phages (type 14) were unusual in that they were predominant on this host at all sampling times (between 53% and 82% nodule occupancy) and were relatively homogeneous on the basis of DNA hybridization with 98% of the isolates analysed sharing the same nod EFG hybridization profile. In contrast, those isolates from M. alba comprising type 14 were encountered at low total frequency (2%) and were genetically heterogeneous on the basis of Southern hybridization. The implications of the observed

  13. A snapshot of functional genetic studies in Medicago truncatula

    Directory of Open Access Journals (Sweden)

    Yun Kang

    2016-08-01

    Full Text Available In the current context of food security, increase of plant protein production in a sustainable manner represents one of the major challenges of agronomic research, which could be partially resolved by increased cultivation of legume crops. Medicago truncatula is now a well-established model for legume genomic and genetic studies. With the establishment of genomics tools and mutant populations in M. truncatula, it has become an important resource to answer some of the basic biological questions related to plant development and stress tolerance. This review has an objective to overview a decade of genetic studies in this model plant from generation of mutant populations to nowadays. To date, the three biological fields, which have been extensively studied in M. truncatula, are the symbiotic nitrogen fixation, the seed development, and the abiotic stress tolerance, due to their significant agronomic impacts. In this review, we summarize functional genetic studies related to these three major biological fields. We integrated analyses of a nearly exhaustive list of genes into their biological contexts in order to provide an overview of the forefront research advances in this important legume model plant.

  14. Bioinformatics Analysis of MAPKKK Family Genes in Medicago truncatula

    Science.gov (United States)

    Li, Wei; Xu, Hanyun; Liu, Ying; Song, Lili; Guo, Changhong; Shu, Yongjun

    2016-01-01

    Mitogen-activated protein kinase kinase kinase (MAPKKK) is a component of the MAPK cascade pathway that plays an important role in plant growth, development, and response to abiotic stress, the functions of which have been well characterized in several plant species, such as Arabidopsis, rice, and maize. In this study, we performed genome-wide and systemic bioinformatics analysis of MAPKKK family genes in Medicago truncatula. In total, there were 73 MAPKKK family members identified by search of homologs, and they were classified into three subfamilies, MEKK, ZIK, and RAF. Based on the genomic duplication function, 72 MtMAPKKK genes were located throughout all chromosomes, but they cluster in different chromosomes. Using microarray data and high-throughput sequencing-data, we assessed their expression profiles in growth and development processes; these results provided evidence for exploring their important functions in developmental regulation, especially in the nodulation process. Furthermore, we investigated their expression in abiotic stresses by RNA-seq, which confirmed their critical roles in signal transduction and regulation processes under stress. In summary, our genome-wide, systemic characterization and expressional analysis of MtMAPKKK genes will provide insights that will be useful for characterizing the molecular functions of these genes in M. truncatula. PMID:27049397

  15. Root developmental programs shape the Medicago truncatula nodule meristem.

    Science.gov (United States)

    Franssen, Henk J; Xiao, Ting Ting; Kulikova, Olga; Wan, Xi; Bisseling, Ton; Scheres, Ben; Heidstra, Renze

    2015-09-01

    Nodules on the roots of legume plants host nitrogen-fixing Rhizobium bacteria. Several lines of evidence indicate that nodules are evolutionarily related to roots. We determined whether developmental control of the Medicago truncatula nodule meristem bears resemblance to that in root meristems through analyses of root meristem-expressed PLETHORA genes. In nodules, MtPLETHORA 1 and 2 are preferentially expressed in cells positioned at the periphery of the meristem abutting nodule vascular bundles. Their expression overlaps with an auxin response maximum and MtWOX5, which is a marker for the root quiescent center. Strikingly, the cells in the central part of the nodule meristem have a high level of cytokinin and display MtPLETHORA 3 and 4 gene expression. Nodule-specific knockdown of MtPLETHORA genes results in a reduced number of nodules and/or in nodules in which meristem activity has ceased. Our nodule gene expression map indicates that the nodule meristem is composed of two distinct domains in which different MtPLETHORA gene subsets are expressed. Our mutant studies show that MtPLETHORA genes function redundantly in nodule meristem maintenance. This indicates that Rhizobium has recruited root developmental programs for nodule formation. © 2015. Published by The Company of Biologists Ltd.

  16. Host and nonhost resistance in Medicago-Colletotrichum interactions.

    Science.gov (United States)

    Jaulneau, Valérie; Cazaux, Marc; Wong Sak Hoi, Joanne; Fournier, Sylvie; Esquerré-Tugayé, Marie-Thérèse; Jacquet, Christophe; Dumas, Bernard

    2010-09-01

    Medicago truncatula lines resistant (A17) or susceptible (F83005.5) to the alfalfa pathogen Colletotrichum trifolii were used to compare defense reactions induced upon inoculation with C. trifolii or with the nonadapted pathogens C. lindemuthianum and C. higginsianum. Nonadapted Colletotrichum spp. induced a hypersensitive response (HR)-like reaction similar to the one induced during the host-incompatible interaction. Molecular analyses indicated an induction of PR10 and chalcone synthase genes in host and nonhost interactions but delayed responses were observed in the F83005.5 line. The clste12 penetration-deficient C. lindemuthianum mutant induced an HR and defense gene expression, showing that perception of nonadapted strains occurs before penetration of epidermal cells. Cytological and transcriptomic analyses performed upon inoculation of near-isogenic M. truncatula lines, differing only at the C. trifolii resistance locus, Ct1, with the nonadapted Colletotrichum strain, showed that nonhost responses are similar in the two lines. These included a localized oxidative burst, accumulation of fluorescent compounds, and transient expression of a small number of genes. Host interactions were characterized by a group of defense and signaling-related genes induced at 3 days postinoculation, associated with an accumulation of salicylic acid. Together, these results show that M. truncatula displays a rapid and transient response to nonadapted Colletotrichum strains and that this response is not linked to the C. trifolii resistance locus.

  17. Bioinformatics Analysis of MAPKKK Family Genes in Medicago truncatula

    Directory of Open Access Journals (Sweden)

    Wei Li

    2016-04-01

    Full Text Available Mitogen‐activated protein kinase kinase kinase (MAPKKK is a component of the MAPK cascade pathway that plays an important role in plant growth, development, and response to abiotic stress, the functions of which have been well characterized in several plant species, such as Arabidopsis, rice, and maize. In this study, we performed genome‐wide and systemic bioinformatics analysis of MAPKKK family genes in Medicago truncatula. In total, there were 73 MAPKKK family members identified by search of homologs, and they were classified into three subfamilies, MEKK, ZIK, and RAF. Based on the genomic duplication function, 72 MtMAPKKK genes were located throughout all chromosomes, but they cluster in different chromosomes. Using microarray data and high‐throughput sequencing‐data, we assessed their expression profiles in growth and development processes; these results provided evidence for exploring their important functions in developmental regulation, especially in the nodulation process. Furthermore, we investigated their expression in abiotic stresses by RNA‐seq, which confirmed their critical roles in signal transduction and regulation processes under stress. In summary, our genome‐wide, systemic characterization and expressional analysis of MtMAPKKK genes will provide insights that will be useful for characterizing the molecular functions of these genes in M. truncatula.

  18. Embryogenesis and plant regeneration of Medicago spp. in tissue culture.

    Science.gov (United States)

    Nagarajan, P; McKenzie, J S; Walton, P D

    1986-02-01

    Ten cultivars and breeding lines from two species of alfalfa (Medicago media and M. sativa) were screened for their ability to produce embryos and plantlets from the root and hypocotyl under three different tissue culture protocols. The three protocols differed in basal salt composition, vitamins, hormones and cytokinin additions. That protocol having a high 2-4,D low cytokinin induction step gave the highest percentage of embryogenic calli in some cultivars and lines. M. media cultivars and breeding lines had a high percentage of embryoid formation. M. sativa cultivars gave no embryoid formation. Two M. media breeding lines (Br1 and Le1), which were intermediate in the percentage of embryogenic calli formed from explants, had the highest number of regenerated plants established in soil. The creeping rooted M. media cultivar Heinrichs produced the highest percentage of embryogenic calli from explants but most of these embryoids were abnormal and failed to grow in soil or vermiculite. Accordingly, successful regeneration is directly related to the quality and quantity of the embryoids produced.

  19. Biofertilizer in the nutritional quality of alfalfa (Medicago sativa L.

    Directory of Open Access Journals (Sweden)

    Rodrigo Luis Lemes

    2016-06-01

    Full Text Available The objective of this study was to evaluate the response of alfalfa (Medicago sativa L. in the nutritional composition to the application of biofertilizers. The experiment was conducted with increasing doses of biofertilizers in a greenhouse at the Faculty of Veterinary Medicine / UNESP, Araçatuba - Sao Paulo, Brazil, from April to October 2010. The experimental design was completely randomized with six biofertilizer doses from cattle manure (0, 25, 50, 100, 200, and 400 m3 ha-1 and five replications. Cuts were performed, on average, every 27 days, 10 cm above the ground when 10% of the plants were flowering. Biofertilization had a positive significant impact on foliar nitrogen, potassium, calcium, magnesium, sulfur, and shoot iron concentrations. The values of crude protein, acid detergent fiber, and neutral detergent fiber did not differ between doses of biofertilizers. Biofertilization is a viable alternative for nutrition of this species, showing positive results in the nutritional composition of alfalfa. However, but long-term studies are necessary to assess the environmental impact of these fertilizers.

  20. Inhibition of the catalase activity from Phaseolus vulgaris and Medicago sativa by sodium chloride.

    Science.gov (United States)

    Tejera García, Noel A; Iribarne, Carmen; Palma, Francisco; Lluch, Carmen

    2007-08-01

    Changes in catalase activity during the development of the Rhizobium-legume symbiosis as well as its response in salinized plants of Phaseolus vulgaris and Medicago sativa, was studied. Besides, it was examined the behavior of the enzyme, isolated from leaves and root nodules, during in vitro incubation with NaCl doses. Nodule catalase activities of both legumes were assayed with several enzyme inhibitors and also purified. Leaf catalase activity of Phaseolus vulgaris and Medicago sativa decreased and increased respectively throughout the ontogeny, but root nodule catalase kept a high and stable value. This last result suggests that both legumes require the maintenance of high nodule catalase in nitrogen-fixing nodules. Under salt stress conditions leaf and nodule catalase activity decreased in both, grain and pasture legumes. Because catalase from leaf of Medicago sativa and nodules of Phaseolus vulgaris were relatively sensitive to NaCl during in vitro experiments, the detoxifying role of this enzyme for H(2)O(2) should be limited in such conditions. Both catalases, from determinate and indeterminate nodules, were affected neither by oxygen nor superoxide radicals but showed a strong (Phaseolus vulgaris) or partial (Medicago sativa) inhibition with dithiothreitol, dithionite and beta-mercaptoethanol. Besides, cyanide was the most potent inhibitor of nodule catalases. Finally, catalases partially purified by immobilized metal ion affinity chromatography migrated at 42 (Phaseolus vulgaris) and 46kDa (Medicago sativa) on SDS-PAGE, whereas native forms on sephacryl S-300 columns exhibited a molecular mass of 59 and 48kDa (Phaseolus vulgaris) and 88 and 53kDa (Medicago sativa).

  1. Bioaccumulation and degradation of pentachloronitrobenzene in Medicago sativa.

    Science.gov (United States)

    Li, Ying Ying; Yang, Hong

    2013-04-15

    Pentachloronitrobenzene (PCNB) is a fungicide belonging to the organochlorine family and used extensively in agriculture for crop production. Many studies have implied that PCNB has become an environmental concern due to its widespread contamination in eco-systems. However, whether PCNB is bioaccumulated, degraded and phytotoxic in plants is poorly understood. In this study, several alfalfa (Medicago sativa) cultivars were grown in soil with PCNB to investigate their absorption and catabolism, including PCNB residues in the soil and PCNB-induced toxic responses in plants. Alfalfa plants varied widely in their ability to accumulate and degrade PCNB. The degradation rate of PCNB was 66.26-77.68% after alfalfa growth in the soils for 20 d, while the rates in the control (soil without alfalfa) were only 48.42%. Moreover, concentrations of PCNB residues in the rhizosphere soil were significantly higher than those in the non-rhizosphere soils. Alfalfa exposed to 10 mg kg(-1) PCNB showed inhibited growth and oxidative damage, but the effects of PCNB on the cultivars differed significantly, indicating that the alfalfa cultivars have different tolerance to PCNB. Activities of invertase (INV), urease (URE), polyphenol oxidase (PPO), alkaline phosphatase (ALP) and acid phosphatase (ACP) were assayed in the treated soils and showed that the enzyme activities were altered after PCNB exposure. The URE, PPO, ALP and ACP activities were increased in soil following the planting of alfalfa. The objective of the study was to analyze the potential of different cultivars of alfalfa to accumulate and degrade PCNB from the contaminated soil. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Transcription reprogramming during root nodule development in Medicago truncatula.

    Directory of Open Access Journals (Sweden)

    Sandra Moreau

    Full Text Available Many genes which are associated with root nodule development and activity in the model legume Medicago truncatula have been described. However information on precise stages of activation of these genes and their corresponding transcriptional regulators is often lacking. Whether these regulators are shared with other plant developmental programs also remains an open question. Here detailed microarray analyses have been used to study the transcriptome of root nodules induced by either wild type or mutant strains of Sinorhizobium meliloti. In this way we have defined eight major activation patterns in nodules and identified associated potential regulatory genes. We have shown that transcription reprogramming during consecutive stages of nodule differentiation occurs in four major phases, respectively associated with (i early signalling events and/or bacterial infection; plant cell differentiation that is either (ii independent or (iii dependent on bacteroid differentiation; (iv nitrogen fixation. Differential expression of several genes involved in cytokinin biosynthesis was observed in early symbiotic nodule zones, suggesting that cytokinin levels are actively controlled in this region. Taking advantage of databases recently developed for M. truncatula, we identified a small subset of gene expression regulators that were exclusively or predominantly expressed in nodules, whereas most other regulators were also activated under other conditions, and notably in response to abiotic or biotic stresses. We found evidence suggesting the activation of the jasmonate pathway in both wild type and mutant nodules, thus raising questions about the role of jasmonate during nodule development. Finally, quantitative RT-PCR was used to analyse the expression of a series of nodule regulator and marker genes at early symbiotic stages in roots and allowed us to distinguish several early stages of gene expression activation or repression.

  3. Salt stress alters DNA methylation levels in alfalfa (Medicago spp).

    Science.gov (United States)

    Al-Lawati, A; Al-Bahry, S; Victor, R; Al-Lawati, A H; Yaish, M W

    2016-02-26

    Modification of DNA methylation status is one of the mechanisms used by plants to adjust gene expression at both the transcriptional and posttranscriptional levels when plants are exposed to suboptimal conditions. Under abiotic stress, different cultivars often show heritable phenotypic variation accompanied by epigenetic polymorphisms at the DNA methylation level. This variation may provide the raw materials for plant breeding programs that aim to enhance abiotic stress tolerance, including salt tolerance. In this study, methylation-sensitive amplified polymorphism (MSAP) analysis was used to assess cytosine methylation levels in alfalfa (Medicago spp) roots exposed to increasing NaCl concentrations (0.0, 8.0, 12.0, and 20.0 dS/m). Eleven indigenous landraces were analyzed, in addition to a salt-tolerant cultivar that was used as a control. There was a slight increase in DNA methylation upon exposure to high levels of soil salinity. Phylogenetic analysis using MSAP showed epigenetic variation within and between the alfalfa landraces when exposed to saline conditions. Based on MSAP and enzyme-linked immunosorbent assay results, we found that salinity increased global DNA methylation status, particularly in plants exposed to the highest level of salinity (20 dS/m). Quantitative reverse transcription-polymerase chain reaction indicated that this might be mediated by the overexpression of methyltransferase homolog genes after exposure to saline conditions. DNA demethylation using 5-azacytidine reduced seedling lengths and dry and fresh weights, indicating a possible decrease in salinity tolerance. These results suggest that salinity affects DNA methylation flexibility.

  4. Beta-Amylases from Alfalfa (Medicago sativa L.) Roots.

    Science.gov (United States)

    Doehlert, D C; Duke, S H; Anderson, L

    1982-05-01

    Amylase was found in high activity (193 international units per milligram protein) in the tap root of alfalfa (Medicago sativa L. cv. Sonora). The activity was separated by gel filtration chromatography into two fractions with molecular weights of 65,700 (heavy amylase) and 41,700 (light amylase). Activity staining of electrophoretic gels indicated the presence of one isozyme in the heavy amylase fraction and two in the light amylase fraction. Three amylase isozymes with electrophoretic mobilities identical to those in the heavy and the light amylase fractions were the only amylases identified in crude root preparations. Both heavy and light amylases hydrolyzed amylopectin, soluble starch, and amylose but did not hydrolyze pullulan or beta-limit dextrin. The ratio of viscosity change to reducing power production during starch hydrolysis was identical for both alfalfa amylase fractions and sweet potato beta-amylase, while that of bacterial alpha-amylase was considerably higher. The identification of maltose and beta-limit dextrin as hydrolytic end-products confirmed that these alfalfa root amylases are all beta-amylases.The pH optimum for both beta-amylase fractions was 6.0. Both light and heavy beta-amylases showed normal Michaelis-Menten kinetics, with soluble starch as substrate, and had respectively K(m) values of 5.9 and 6.8 milligrams starch per milliliter and V(max) of 640 and 130 international units per milligram protein. Arrhenius plots indicated that the energy of activation for the heavy beta-amylase remained relatively unchanged (12.7 to 13.0 kilocalories per mole) from 0 to 30 degrees C, whereas the energy of activation for the light amylase increased from 12.0 to about 28.0 kilocalories per mole at 8.7 degrees C as temperature was lowered. The light amylase was shown to be inhibited by maltose.

  5. CLE peptides control Medicago truncatula nodulation locally and systemically.

    Science.gov (United States)

    Mortier, Virginie; Den Herder, Griet; Whitford, Ryan; Van de Velde, Willem; Rombauts, Stephane; D'Haeseleer, Katrien; Holsters, Marcelle; Goormachtig, Sofie

    2010-05-01

    The CLAVATA3/embryo-surrounding region (CLE) peptides control the fine balance between proliferation and differentiation in plant development. We studied the role of CLE peptides during indeterminate nodule development and identified 25 MtCLE peptide genes in the Medicago truncatula genome, of which two genes, MtCLE12 and MtCLE13, had nodulation-related expression patterns that were linked to proliferation and differentiation. MtCLE13 expression was up-regulated early in nodule development. A high-to-low expression gradient radiated from the inner toward the outer cortical cell layers in a region defining the incipient nodule. At later stages, MtCLE12 and MtCLE13 were expressed in differentiating nodules and in the apical part of mature, elongated nodules. Functional analysis revealed a putative role for MtCLE12 and MtCLE13 in autoregulation of nodulation, a mechanism that controls the number of nodules and involves systemic signals mediated by a leucine-rich repeat receptor-like kinase, SUNN, which is active in the shoot. When MtCLE12 and MtCLE13 were ectopically expressed in transgenic roots, nodulation was abolished at the level of the nodulation factor signal transduction, and this inhibition involved long-distance signaling. In addition, composite plants with roots ectopically expressing MtCLE12 or MtCLE13 had elongated petioles. This systemic effect was not observed in transgenic roots ectopically expressing MtCLE12 and MtCLE13 in a sunn-1 mutant background, although nodulation was still strongly reduced. These results suggest multiple roles for CLE signaling in nodulation.

  6. Small RNA deep sequencing identifies novel and salt-stress-regulated microRNAs from roots of Medicago sativa and Medicago truncatula.

    Science.gov (United States)

    Long, Rui-Cai; Li, Ming-Na; Kang, Jun-Mei; Zhang, Tie-Jun; Sun, Yan; Yang, Qing-Chuan

    2015-05-01

    Small 21- to 24-nucleotide (nt) ribonucleic acids (RNAs), notably the microRNA (miRNA), are emerging as a posttranscriptional regulation mechanism. Salt stress is one of the primary abiotic stresses that cause the crop losses worldwide. In saline lands, root growth and function of plant are determined by the action of environmental salt stress through specific genes that adapt root development to the restrictive condition. To elucidate the role of miRNAs in salt stress regulation in Medicago, we used a high-throughput sequencing approach to analyze four small RNA libraries from roots of Zhongmu-1 (Medicago sativa) and Jemalong A17 (Medicago truncatula), which were treated with 300 mM NaCl for 0 and 8 h. Each library generated about 20 million short sequences and contained predominantly small RNAs of 24-nt length, followed by 21-nt and 22-nt small RNAs. Using sequence analysis, we identified 385 conserved miRNAs from 96 families, along with 68 novel candidate miRNAs. Of all the 68 predicted novel miRNAs, 15 miRNAs were identified to have miRNA*. Statistical analysis on abundance of sequencing read revealed specific miRNA showing contrasting expression patterns between M. sativa and M. truncatula roots, as well as between roots treated for 0 and 8 h. The expression of 10 conserved and novel miRNAs was also quantified by quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). The miRNA precursor and target genes were predicted by bioinformatics analysis. We concluded that the salt stress related conserved and novel miRNAs may have a large variety of target mRNAs, some of which might play key roles in salt stress regulation of Medicago.

  7. Induction of peroxidases and superoxide dismutases in transformed embryogenic calli of alfalfa (Medicago sativa L.)

    Science.gov (United States)

    Activities of peroxidase (POD) and superoxide dismutase (SOD) enzymes were analyzed in non-regenerative transformed embryogenic lines of alfalfa (Medicago sativa L.) carrying wound-inducible oryzacystatin I (OC-I), wound-inducible oryzacystatin I antisense (OC-Ias) or hygromycin phosphotransferase (...

  8. Transformation of Medicago truncatula via infiltration of seedlings or flowering plants with Agrobacterium

    DEFF Research Database (Denmark)

    Trieu, A.T.; Burleigh, S.H.; Kardailsky, I.V.

    2000-01-01

    Two rapid and simple in planta transformation methods have been developed for the model legume Medicago truncatula. The first approach is based on a method developed for transformation of Arabidopsis thaliana and involves infiltration of flowering plants with a suspension of Agrobacterium. The se...

  9. Discovery AP2/ERF family genes in silico in Medicago truncatula

    African Journals Online (AJOL)

    aghomotsegin

    Medicago truncatula is a legume model plant due to its small genome and it has been used to study the molecular ... To investigate the roles of AP2/EREBP in M. truncatula, ..... Zhuang J, Chen JM, Yao QH, Xiong F, Sun CC, Zhou XR, Zhang J,.

  10. Integration and Expression of gfp in the plastid of Medicago sativa L.

    Science.gov (United States)

    Xing, Shaochen; Wei, Zhengyi; Wang, Yunpeng; Liu, Yanzhi; Lin, Chunjing

    2014-01-01

    Here we describe a protocol of alfalfa (Medicago sativa L.) plastid transformation by which gfp, a gene encoding the green fluorescent protein (GFP), is inserted into plastid genome via particle bombardment and homoplastomic plant is obtained. Plastid engineering is likely to make a significant contribution to the genetic improvement of this crop and the production of vaccines and therapeutic proteins.

  11. In silico identification of known osmotic stress responsive genes from Arabidopsis in soybean and Medicago

    Directory of Open Access Journals (Sweden)

    Nina M. Soares-Cavalcanti

    2012-01-01

    Full Text Available Plants experience various environmental stresses, but tolerance to these adverse conditions is a very complex phenomenon. The present research aimed to evaluate a set of genes involved in osmotic response, comparing soybean and medicago with the well-described Arabidopsis thaliana model plant. Based on 103 Arabidopsis proteins from 27 categories of osmotic stress response, comparative analyses against Genosoja and Medicago truncatula databases allowed the identification of 1,088 soybean and 1,210 Medicago sequences. The analysis showed a high number of sequences and high diversity, comprising genes from all categories in both organisms. Genes with unknown function were among the most representative, followed by transcription factors, ion transport proteins, water channel, plant defense, protein degradation, cellular structure, organization & biogenesis and senescence. An analysis of sequences with unknown function allowed the annotation of 174 soybean and 217 Medicago sequences, most of them concerning transcription factors. However, for about 30% of the sequences no function could be attributed using in silico procedures. The establishment of a gene set involved in osmotic stress responses in soybean and barrel medic will help to better understand the survival mechanisms for this type of stress condition in legumes.

  12.  Molecular evolution and positive selection of the symbiotic gene NORK in Medicago truncatula

    DEFF Research Database (Denmark)

    De Mita, Stephane; Santoni, Sylvain; Hochu, Isabelle

    2006-01-01

    . The membrane-anchored receptor NORK (nodulation receptor kinase) of the legume Medicago truncatula controls early steps of root infection by two symbiotic microorganisms: nitrogen-fixing bacteria (rhizobia) and endomycorrhizal fungi (Glomales). We analyzed the diversity of the gene NORK by sequencing 4...

  13. Identification of novel RNA viruses in alfalfa (Medicago sativa): an Alphapartitivirus, a Deltapartitivirus and a Marafivirus.

    Science.gov (United States)

    Kim, Hyein; Park, Dongbin; Hahn, Yoonsoo

    2017-09-30

    Genomic RNA molecules of plant RNA viruses are often co-isolated with the host RNAs, and their sequences can be detected in plant transcriptome datasets. Here, an alfalfa (Medicago sativa) transcriptome dataset was analyzed and three new RNA viruses were identified, which were named Medicago sativa alphapartitivirus 1 (MsAPV1), Medicago sativa deltapartitivirus 1 (MsDPV1), and Medicago sativa marafivirus 1 (MsMV1). The RNA-dependent RNA polymerases of MsAPV1, MsDPV1, and MsMV1 showed about 68%, 58%, and 46% amino acid sequence identity, respectively, with their closest virus species. Sequence similarity and phylogenetic analyses indicated that MsAPV1, MsDPV1, and MsMV1 were novel RNA virus species that belong to the genus Alphapartitivirus of the family Partitiviridae, the genus Deltapartitivirus of the family Partitiviridae, and the genus Marafivirus of the family Tymoviridae, respectively. The bioinformatics procedure applied in this study may facilitate the identification of novel RNA viruses from plant transcriptome data. Copyright © 2017. Published by Elsevier B.V.

  14. Molecular signals controlling the inhibition of nodulation by nitrate in Medicago truncatula

    NARCIS (Netherlands)

    Noorden, Van Giel E.; Verbeek, Rob; Dinh, Peter; Jin, Jian; Green, Alexandra; Ng, Jason Liang Pin; Mathesius, Ulrike

    2016-01-01

    The presence of nitrogen inhibits legume nodule formation, but the mechanism of this inhibition is poorly understood. We found that 2.5 mM nitrate and above significantly inhibited nodule initiation but not root hair curling in Medicago trunatula. We analyzed protein abundance in M. truncatula ro

  15. Analysis of nodule meristem persistence and ENOD40 functioning in Medicago truncatula nodule formation

    NARCIS (Netherlands)

    Wan Xi,

    2007-01-01

    Medicago root nodules are formed as a result of the interaction of the plant with the soil-borne bacterium Sinorhizobium meliloti. Several plant genes are induced during nodule formation and MtENOD40 is one of the earliest genes activated. The precise function as well as the molecule harboring the b

  16. An integrated physical, genetic and cytogenetic map around the sunn locus of Medicago truncatula

    NARCIS (Netherlands)

    Schnabel, E.; Kulikova, O.; Penmetsa, R.V.; Bisseling, T.; Cook, D.R.; Frugoli, J.

    2003-01-01

    The sunn mutation of Medicago truncatula is a single-gene mutation that confers a novel supernodulation phenotype in response to inoculation with Sinorhizobium meliloti. We took advantage of the publicly available codominant PCR markers, the high-density genetic map, and a linked cytogenetic map to

  17. Integration of the FISH pachytene and genetic maps of Medicago truncatula.

    NARCIS (Netherlands)

    Kulikova, O.; Gualtieri, G.; Geurts, R.; Kim, D.J.; Cook, D.; Huguet, T.; Jong, de J.H.; Fransz, P.F.; Bisseling, T.

    2001-01-01

    A molecular cytogenetic map of Medicago truncatula (2n = 2x = 16) was constructed on the basis of a pachytene DAPI karyogram. Chromosomes at this meiotic prophase stage are 20 times longer than at mitotic metaphase, and display a well differentiated pattern of brightly fluorescing heterochromatin se

  18. First report of race 2 of Colletotrichum trifolii causing anthracnose on alfalfa (Medicago sativa) in Wisconsin

    Science.gov (United States)

    Anthracnose of alfalfa (Medicago sativa), caused by Colletotrichum trifolii, is widespread in the United States. Three physiological races have been described. Race 1 is reported to be the dominant race that is present wherever alfalfa is grown, while race 2 was reported in a limited area in the Mid...

  19. Spatio-temporal expression patterns of Arabidopsis thaliana and Medicago truncatula defensin-like genes.

    Directory of Open Access Journals (Sweden)

    Mesfin Tesfaye

    Full Text Available Plant genomes contain several hundred defensin-like (DEFL genes that encode short cysteine-rich proteins resembling defensins, which are well known antimicrobial polypeptides. Little is known about the expression patterns or functions of many DEFLs because most were discovered recently and hence are not well represented on standard microarrays. We designed a custom Affymetrix chip consisting of probe sets for 317 and 684 DEFLs from Arabidopsis thaliana and Medicago truncatula, respectively for cataloging DEFL expression in a variety of plant organs at different developmental stages and during symbiotic and pathogenic associations. The microarray analysis provided evidence for the transcription of 71% and 90% of the DEFLs identified in Arabidopsis and Medicago, respectively, including many of the recently annotated DEFL genes that previously lacked expression information. Both model plants contain a subset of DEFLs specifically expressed in seeds or fruits. A few DEFLs, including some plant defensins, were significantly up-regulated in Arabidopsis leaves inoculated with Alternaria brassicicola or Pseudomonas syringae pathogens. Among these, some were dependent on jasmonic acid signaling or were associated with specific types of immune responses. There were notable differences in DEFL gene expression patterns between Arabidopsis and Medicago, as the majority of Arabidopsis DEFLs were expressed in inflorescences, while only a few exhibited root-enhanced expression. By contrast, Medicago DEFLs were most prominently expressed in nitrogen-fixing root nodules. Thus, our data document salient differences in DEFL temporal and spatial expression between Arabidopsis and Medicago, suggesting distinct signaling routes and distinct roles for these proteins in the two plant species.

  20. Spatio-temporal expression patterns of Arabidopsis thaliana and Medicago truncatula defensin-like genes.

    Science.gov (United States)

    Tesfaye, Mesfin; Silverstein, Kevin At; Nallu, Sumitha; Wang, Lin; Botanga, Christopher J; Gomez, S Karen; Costa, Liliana M; Harrison, Maria J; Samac, Deborah A; Glazebrook, Jane; Katagiri, Fumiaki; Gutierrez-Marcos, Jose F; Vandenbosch, Kathryn A

    2013-01-01

    Plant genomes contain several hundred defensin-like (DEFL) genes that encode short cysteine-rich proteins resembling defensins, which are well known antimicrobial polypeptides. Little is known about the expression patterns or functions of many DEFLs because most were discovered recently and hence are not well represented on standard microarrays. We designed a custom Affymetrix chip consisting of probe sets for 317 and 684 DEFLs from Arabidopsis thaliana and Medicago truncatula, respectively for cataloging DEFL expression in a variety of plant organs at different developmental stages and during symbiotic and pathogenic associations. The microarray analysis provided evidence for the transcription of 71% and 90% of the DEFLs identified in Arabidopsis and Medicago, respectively, including many of the recently annotated DEFL genes that previously lacked expression information. Both model plants contain a subset of DEFLs specifically expressed in seeds or fruits. A few DEFLs, including some plant defensins, were significantly up-regulated in Arabidopsis leaves inoculated with Alternaria brassicicola or Pseudomonas syringae pathogens. Among these, some were dependent on jasmonic acid signaling or were associated with specific types of immune responses. There were notable differences in DEFL gene expression patterns between Arabidopsis and Medicago, as the majority of Arabidopsis DEFLs were expressed in inflorescences, while only a few exhibited root-enhanced expression. By contrast, Medicago DEFLs were most prominently expressed in nitrogen-fixing root nodules. Thus, our data document salient differences in DEFL temporal and spatial expression between Arabidopsis and Medicago, suggesting distinct signaling routes and distinct roles for these proteins in the two plant species.

  1. Denitrification by Rhizobium meliloti

    Energy Technology Data Exchange (ETDEWEB)

    Rosen, A.

    1996-10-01

    Rhizobium meliloti strains were investigated for their denitrification activity as free-living cells and in nodules on lucerne (Medicago sativa) roots. They were also investigated for presence of nitrous oxide reductase (nos) activity and for genes using a nosZ probe derived from the Pseudomonas stutzeri. To decide whether R. meliloti strains used as inoculants contribute to the total denitrification activity in a lucerne ley, strains with different denitrifying capacities were used in field and laboratory experiments. The nitrate reduction activity of R. meliloti during anaerobic respiration was compared with that of a strain of Pseudomonas aeruginosa. A great diversity in the denitrification activity was found within strains of R. meliloti, and four of thirteen investigated strains showed an obvious denitrification activity. Two denitrifying bacteria were used as references, one strain each of Bradyrhizobium japonicum and P. aeruginosa. All but one of the R. meliloti strains hybridized to the PstI-fragment of the nosZ-gene from P. stutzeri. Two sizes of the hybridizing fragment, 5 and 7 kb, were noticed. Nos activity was only shown in three R. meliloti strains, and these were all characterized by a high denitrification activity. The potential denitrification activity was about 20, 40, and 80 times higher than the actual denitrification activity for lucerne, fallow, and grass, respectively. The potential denitrification activity was almost the same in lucerne and grass planted soils. Compared with the unplanted soil, the presence of lucerne roots in the soil increased the actual denitrification activity, while roots of both plant species, grass and lucerne, increased the potential denitrification activity in the soil. 32 refs, 7 figs, 1 tab

  2. Starch Grain Distribution in Taproots of Defoliated Medicago sativa L.

    Science.gov (United States)

    Habben, J E; Volenec, J J

    1990-11-01

    Defoliation of alfalfa (Medicago sativa L.) results in a cyclic pattern of starch degradation followed by reaccumulation in taproots. Characterization of changes in anatomical distribution of starch grains in taproots will aid our understanding of biochemical and physiological mechanisms involved in starch metabolism in taproots of this species. Our objectives were to determine the influence of defoliation on starch grain distribution and size variation in taproots of two alfalfa lines selected for contrasting concentrations of taproot starch. In addition, we used electron microscopy to examine the cellular environment of starch grains, and computer-based image optical analysis to determine how cross-sectional area of tissues influenced starch accumulation. Taproots of field-grown plants were sampled at defoliation and weekly thereafter over a 28-day period. Taproot segments were fixed in glutaraldehyde and prepared for either light or electron microscopy. Transverse sections were examined for number and size of starch grains and tissue areas were measured. Starch grains were located throughout bark tissues, but were confined primarily to ray parenchyma cells in wood tissues. During the first week of foliar regrowth after defoliation, starch grains in ray cells near the cambium disappeared first, while degradation of those near the center of the taproot was delayed. During the third and fourth weeks of regrowth, there was a uniform increase in number of starch grains per cell profile across the rays, but by 28 days after defoliation there were more starch grains in ray cells near the cambium than in cells near the center of the taproot (low starch line only). Bark tissues from both lines showed synchronous degradation and synthesis of starch grains that was not influenced greatly by cell location. Diameter of starch grains varied with cell location in medullary rays during rapid starch degradation, but was not influenced by cell position in bark tissues. Therefore

  3. Activity and multiple forms of peroxidase in Zea mays and Medicago sativa treated and non-treated with lead

    Energy Technology Data Exchange (ETDEWEB)

    Maier, R.

    1978-02-11

    The influence of lead on peroxidase was studied in young plants of Zee mays and Medicago sativa grown in solutions of Pb(NO/sub 3/)/sub 2/. The content of nitrate in the control- and the lead-solutions was equalized by NaNO/sub 3/. In the patterns of the multiple forms in roots and leaves of Zea and Medicago qualitatively no, or respectively negligible, change between control and lead-treated plants takes place. The temperature during the lead-treatment does not effect the numbers and the positions of bands. The bands' activity of peroxidase in lead-treated plants differs clearly from untreated plants, resulting in a different activity of the whole enzyme. In the roots and in the leaves of Zea as well as in the leaves of Medicago the relative activity of the peroxidase in lead-treated plants is raised. In the roots of Medicago the relative activity decreased slightly.

  4. Ensifer, Phyllobacterium and Rhizobium species occupy nodules of Medicago sativa (alfalfa) and Melilotus alba (sweet clover) grown at a Canadian site without a history of cultivation.

    Science.gov (United States)

    Bromfield, E S P; Tambong, J T; Cloutier, S; Prévost, D; Laguerre, G; van Berkum, P; Thi, T V Tran; Assabgui, R; Barran, L R

    2010-02-01

    Phage-resistant and -susceptible bacteria from nodules of alfalfa and sweet clover, grown at a site without a known history of cultivation, were identified as diverse genotypes of Ensifer, Rhizobium and Phyllobacterium species based on sequence analysis of ribosomal (16S and 23S rRNA) and protein-encoding (atpD and recA) genes, Southern hybridization/RFLP and a range of phenotypic characteristics. Among phage-resistant bacteria, one genotype of Rhizobium sp. predominated on alfalfa (frequency approximately 68 %) but was recovered infrequently ( approximately 1 %) from sweet clover. A second genotype was isolated infrequently only from alfalfa. These genotypes fixed nitrogen poorly in association with sweet clover and Phaseolus vulgaris, but were moderately effective with alfalfa. They produced a near-neutral reaction on mineral salts agar containing mannitol, which is atypical of the genus Rhizobium. A single isolate of Ensifer sp. and two of Phyllobacterium sp. were recovered only from sweet clover. All were highly resistant to multiple antibiotics. Phylogenetic analysis indicated that Ensifer sp. strain T173 is closely related to, but separate from, the non-symbiotic species 'Sinorhizobium morelense'. Strain T173 is unique in that it possesses a 175 kb symbiotic plasmid and elicits ineffective nodules on alfalfa, sweet clover, Medicago lupulina and Macroptilium atropurpureum. The two Phyllobacterium spp. were non-symbiotic and probably represent bacterial opportunists. Three genotypes of E. meliloti that were symbiotically effective with alfalfa and sweet clover were encountered infrequently. Among phage-susceptible isolates, two genotypes of E. medicae were encountered infrequently and were highly effective with alfalfa, sweet clover and Medicago polymorpha. The ecological and practical implications of the findings are discussed.

  5. MtPAR MYB transcription factor acts as an on switch for proanthocyanidin biosynthesis in Medicago truncatula

    OpenAIRE

    2012-01-01

    MtPAR (Medicago truncatula proanthocyanidin regulator) is an MYB family transcription factor that functions as a key regulator of proanthocyanidin (PA) biosynthesis in the model legume Medicago truncatula. MtPAR expression is confined to the seed coat, the site of PA accumulation. Loss-of-function par mutants contained substantially less PA in the seed coat than the wild type, whereas levels of anthocyanin and other specialized metabolites were normal in the mutants. In contrast, massive accu...

  6. Environmental Impact Research Program: Alfalfa (Medicago sativa). Section 7.3.1, U.S. Army Corps of Engineers Wildlife Resources Management Manual.

    Science.gov (United States)

    1986-07-01

    ADAl?3 141 ENVIRONMENTAL IMPACT RESEARCH PROGRAM: ALFALFA 1/1 ( MEDICAGO SATIVA ) SECTION 7..(U) ARMY ENGINEER7F R ?’ 4 N OM ENRATERWAYS EXPERIMENT... Medicago sativa ) Section 7.3.1, US ARMY CORPS OF ENGINEERS WILDLIFE RESOURCES MANAGEMENT MANUAL CV) P% by Clinton H. Wasser Colorado State University Fort...20314-1000 EIRP 31631.. 11 TITLE (Include Security Classification) Alfalfa ( Medicago sativa ): Section 7.3.1, US Army Corps of Engineers Wildlife

  7. Three way interactions between Thymus vulgaris, Medicago truncatula and Sinorhizobium meliloti

    DEFF Research Database (Denmark)

    Grøndahl, Eva; Ehlers, Bodil Kirstine

    2012-01-01

    shows patterns of adaptation to its thyme neighbor, and 2) if any adaptive response was dependent on the rhizobium, and whether the rhizobium was either "experienced" or "naive" with respect to thyme monoterpenes. Using a G*G*E design, the fitness of 13 genotypes of Medicago truncatula was tested....... Of these genotypes, 7 were ”experienced”, and 6 were ”naive” to thyme. All genotypes were grown on soil either amended with thyme monoterpene or not. In addition, each plant received a rhizobium treatment, which was either: no rhizobium, a mix of thyme experienced Sinorhizobium genotypes, or a mix of thyme naive...... Sinorhizobium. The experiment was carried out as a fully factorial design. As a fitness parameter, number of offspring (pods) were counted after harvest. The results showed a large effect of Medicago genotype on plant fitness. Thyme naive rhizobium overall had a more positive effect on plant fitness than thyme...

  8. Cloning and Characterization of a Novel Purple Acid Phosphatase Gene (MtPAP1) from Medicago truncatula Barrel Medic

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A novel purple acid phosphatase gene (MtPAP1) was isolated from the model legume Medicago truncatula Barrel Medic. The cDNA was 1 698 bp in length with an open reading frame (ORF) of 1 398 bp capable of encoding an N-terminal signal peptide of 23 amino acids. The transcripts of MtPAP1 were mainly detected in leaves under high-phosphate conditions, whereas under low-phosphate conditions the transcript level was reduced in leaves and increased in roots, with the strongest hybridization signal detected in roots. A chimeric gene construct fusing MtPAP1 and GFPwas made in which the fusion was driven by the CaMV35S promoter. Transgenlc Arabidopsis plants carrying the chimeric gene constructs showed that the fusion protein was mainly located at the apoplast based on confocal microscopic analysis, showing that MtPAP1 could be secreted to the outside of the cell directed by the signal peptide at the N-terminal. The coding region of MtPAP1 without signal peptide was inserted into the prokaryotic expression vector pET-30a (+) and overexpressed in Escherlchia coll BL21(DE3). The acid phosphatase (APase) proteins extracted from bacterial culture were found largely based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. An enzyme activity assay demonstrated that the APase activity in the transformed bacteria was 3.16-fold higher than that of control. The results imply that MtPAP1 functions to improve phosphorus acquisition in plants under conditions of phosphorus (P) stress.

  9. A tandem Kunitz protease inhibitor (KPI106)-serine carboxypeptidase (SCP1) controls mycorrhiza establishment and arbuscule development in Medicago truncatula.

    Science.gov (United States)

    Rech, Stefanie S; Heidt, Sven; Requena, Natalia

    2013-09-01

    Plant proteases and protease inhibitors are involved in plant developmental processes including those involving interactions with microbes. Here we show that a tandem between a Kunitz protease inhibitor (KPI106) and a serine carboxypeptidase (SCP1) controls arbuscular mycorrhiza development in the root cortex of Medicago truncatula. Both proteins are only induced during mycorrhiza formation and belong to large families whose members are also mycorrhiza-specific. Furthermore, the interaction between KPI106 and SCP1 analysed using the yeast two-hybrid system is specific, indicating that each family member might have a defined counterpart. In silico docking analysis predicted a putative P1 residue in KPI106 (Lys173) that fits into the catalytic pocket of SCP1, suggesting that KPI106 might inhibit the enzyme activity by mimicking the protease substrate. In vitro mutagenesis of the Lys173 showed that this residue is important in determining the strength and specificity of the interaction. The RNA interference (RNAi) inactivation of the serine carboxypeptidase SCP1 produces aberrant mycorrhizal development with an increased number of septated hyphae and degenerate arbuscules, a phenotype also observed when overexpressing KPI106. Protease and inhibitor are both secreted as observed when expressed in Nicotiana benthamiana epidermal cells. Taken together we envisage a model in which the protease SCP1 is secreted in the apoplast where it produces a peptide signal critical for proper fungal development within the root. KPI106 also at the apoplast would modulate the spatial and/or temporal activity of SCP1 by competing with the protease substrate.

  10. Agrophysiological and biochemical properties associated with adaptation of Medicago sativa populations to water deficit

    OpenAIRE

    Farissi, Mohamed; BOUIZGAREN, Abdelaziz; FAGHIRE, Mustapha; Bargaz, Adnane; Ghoulam, Cherki

    2013-01-01

    The effect of water deficit on growth and some physiological and biochemical parameters related to water deficit tolerance was studied in 4 Moroccan alfalfa Medicago sativa L. populations that originated from the mountains and oases of Morocco. The experiment was conducted in greenhouse conditions. Seeds were allowed to germinate in pots filled with sand and peat at a 2:1 ratio, respectively. After 1 month of sowing, the plants were subjected to 3 water regimes: optimal irrigation (75% of fie...

  11. Concerted changes in N and C primary metabolism in alfalfa (Medicago sativa) under water restriction

    OpenAIRE

    Aranjuelo, Iker; Tcherkez, Guillaume,; Molero, Gemma; Gilard, Françoise; AVICE, JEAN-CHRISTOPHE; Nogués, Salvador

    2013-01-01

    Although the mechanisms of nodule N2 fixation in legumes are now well documented, some uncertainty remains on the metabolic consequences of water deficit. In most cases, little consideration is given to other organs and, therefore, the coordinated changes in metabolism in leaves, roots, and nodules are not well known. Here, the effect of water restriction on exclusively N2-fixing alfalfa (Medicago sativa L.) plants was investigated, and proteomic, metabolomic, and physiological analyses were ...

  12. Micromonospora from nitrogen fixing nodules of alfalfa (Medicago sativa L.). A new promising Plant Probiotic Bacteria.

    OpenAIRE

    Pilar Martínez-Hidalgo; Purificación Galindo-Villardón; Trujillo, Martha E.; Igual, José M.; Eustoquio Martínez-Molina

    2014-01-01

    Biotic interactions can improve agricultural productivity without costly and environmentally challenging inputs. Micromonospora strains have recently been reported as natural endophytes of legume nodules but their significance for plant development and productivity has not yet been established. The aim of this study was to determine the diversity and function of Micromonospora isolated from Medicago sativa root nodules. Micromonospora-like strains from field alfalfa nodules were characteri...

  13. A combined histology and transcriptome analysis unravels novel questions on Medicago truncatula seed coat

    OpenAIRE

    Verdier, Jerome; Dessaint, Fabrice; Schneider, Charles; Abirached-Darmency, Mona

    2012-01-01

    The seed coat is involved in the determination of seed quality traits such as seed size, seed composition, seed permeability, and hormonal regulation. Understanding seed coat structure is therefore a prerequisite to deciphering the genetic mechanisms that govern seed coat functions. By combining histological and transcriptomic data analyses, cellular and molecular events occurring during Medicago truncatula seed coat development were dissected in order to relate structure to function and pinp...

  14. Regeneration of foreign genes co-transformed plants of Medicago sativa L by Agrobacterium rhizogenes

    Institute of Scientific and Technical Information of China (English)

    吕德扬; 曹学远; 唐顺学; 田霞

    2000-01-01

    Gene encoding sulphur amino acid-rich protein (HNP) and rol genes were transferred into Medicago sativa L (alfalfa) mediated by Agrobacterium tumafeciens. Regeneration of trans-genie plants was induced successfully from hairy root tissue of cotyledon in alfalfa. Cotyledon tissues were an ideally transformed recipient. There was a negative correlation between age of hairy roots and embryogenesis frequency in alfalfa. Production of co-transformed plants with greater yield and super quality was important for development of new alfalfa varieties.

  15. Regeneration of foreign genes co-transformed plants of Medicago sativa L by Agrobacterium rhizogenes

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Gene encoding sulphur amino acid-rich protein (HNP) and rol genes were transferred into Medicago sativa L (alfalfa) mediated by Agrobacterium tumafeciens. Regeneration of transgenic plants was induced successfully from hairy root tissue of cotyledon in alfalfa. Cotyledon tissues were an ideally transformed recipient. There was a negative correlation between age of hairy roots and embryogenesis frequency in alfalfa. Production of co-transformed plants with greater yield and super quality was important for development of new alfalfa varieties.

  16. Using an ecophysiological framework for characterizing germination and heterotrophic growth of several genotypes of Medicago truncatula

    OpenAIRE

    Brunel, Sophie

    2008-01-01

    Germination and growth of heterotrophic stages are crucial steps for crop establishment. They highly depend on environmental conditions. The analytical framework provided by the emergence model SIMPLE (SImulation of PLant Emergence) has been used for the characterization of Medicago truncatula (M.tr.) during the early stages of its cycle in response to seedbeds physical factors with major impacts on emergence: temperature, water potential, mechanical obstacles. M.tr. is a model species. It wa...

  17. A functional genomics approach to (iso)flavonoid glycosylation in the model legume Medicago truncatula.

    Science.gov (United States)

    Modolo, Luzia V; Blount, Jack W; Achnine, Lahoucine; Naoumkina, Marina A; Wang, Xiaoqiang; Dixon, Richard A

    2007-07-01

    Analysis of over 200,000 expressed sequence tags from a range of Medicago truncatula cDNA libraries resulted in the identification of over 150 different family 1 glycosyltransferase (UGT) genes. Of these, 63 were represented by full length clones in an EST library collection. Among these, 19 gave soluble proteins when expressed in E. coli, and these were screened for catalytic activity against a range of flavonoid and isoflavonoid substrates using a high-throughput HPLC assay method. Eight UGTs were identified with activity against isoflavones, flavones, flavonols or anthocyanidins, and several showed high catalytic specificity for more than one class of (iso)flavonoid substrate. All tested UGTs preferred UDP-glucose as sugar donor. Phylogenetic analysis indicated that the Medicago (iso)flavonoid glycosyltransferase gene sequences fell into a number of different clades, and several clustered with UGTs annotated as glycosylating non-flavonoid substrates. Quantitative RT-PCR and DNA microarray analysis revealed unique transcript expression patterns for each of the eight UGTs in Medicago organs and cell suspension cultures, and comparison of these patterns with known phytochemical profiles suggested in vivo functions for several of the enzymes.

  18. Accumulation of heavy metals in Medicago sativa L. and Trifolium pratense L. at the contaminated fluvisol

    Directory of Open Access Journals (Sweden)

    Jakšić Snežana P.

    2013-01-01

    Full Text Available Recently, heavy metals concentrations increased in some agricultural areas due to the consequences of anthropogenic impacts. The aim of this study was to determine the level of heavy metals (As, Cr, Ni and Pb in Medicago sativa L. and Trifolium pratense L. grown on fluvisol, in order to obtain information on safety of these nutrients. The total content of Pb, As, Cr and Ni in the samples of fluvisol was above the maximum allowable amount. The content of heavy metals in Medicago sativa L. and Trifolium pratense L. was below the critical and toxic concentrations in all samples originating from contaminated soil. It was concluded that the accumulation of heavy metals in plants did not depend only on the total content in soil, but also the affinity of the plant, and individual and interactive effects of various soil properties. No statistically significant differences in the accumulation of heavy metals between Medicago sativa L. and Trifolium pratense L were observed. It is necessary to further control of heavy metals in the investigated area, in order to prevent their entry into the food chain and provide healthy food.

  19. cell- and tissue-specific transcriptome analyses of Medicago truncatula root nodules.

    Directory of Open Access Journals (Sweden)

    Erik Limpens

    Full Text Available Legumes have the unique ability to host nitrogen-fixing Rhizobium bacteria as symbiosomes inside root nodule cells. To get insight into this key process, which forms the heart of the endosymbiosis, we isolated specific cells/tissues at different stages of symbiosome formation from nodules of the model legume Medicago truncatula using laser-capture microdissection. Next, we determined their associated expression profiles using Affymetrix Medicago GeneChips. Cells were collected from the nodule infection zone divided into a distal (where symbiosome formation and division occur and proximal region (where symbiosomes are mainly differentiating, as well as infected cells from the fixation zone containing mature nitrogen fixing symbiosomes. As non-infected cells/tissue we included nodule meristem cells and uninfected cells from the fixation zone. Here, we present a comprehensive gene expression map of an indeterminate Medicago nodule and selected genes that show specific enriched expression in the different cells or tissues. Validation of the obtained expression profiles, by comparison to published gene expression profiles and experimental verification, indicates that the data can be used as digital "in situ". This digital "in situ" offers a genome-wide insight into genes specifically associated with subsequent stages of symbiosome and nodule cell development, and can serve to guide future functional studies.

  20. Elicitor-induced transcription factors for metabolic reprogramming of secondary metabolism in Medicago truncatula

    Directory of Open Access Journals (Sweden)

    Dixon Richard A

    2008-12-01

    Full Text Available Abstract Background Exposure of Medicago truncatula cell suspension cultures to pathogen or wound signals leads to accumulation of various classes of flavonoid and/or triterpene defense molecules, orchestrated via a complex signalling network in which transcription factors (TFs are essential components. Results In this study, we analyzed TFs responding to yeast elicitor (YE or methyl jasmonate (MJ. From 502 differentially expressed TFs, WRKY and AP2/EREBP gene families were over-represented among YE-induced genes whereas Basic Helix-Loop-Helix (bHLH family members were more over-represented among the MJ-induced genes. Jasmonate ZIM-domain (JAZ transcriptional regulators were highly induced by MJ treatment. To investigate potential involvement of WRKY TFs in signalling, we expressed four Medicago WRKY genes in tobacco. Levels of soluble and wall bound phenolic compounds and lignin were increased in all cases. WRKY W109669 also induced tobacco endo-1,3-β-glucanase (NtPR2 and enhanced the systemic defense response to tobacco mosaic virus in transgenic tobacco plants. Conclusion These results confirm that Medicago WRKY TFs have broad roles in orchestrating metabolic responses to biotic stress, and that they also represent potentially valuable reagents for engineering metabolic changes that impact pathogen resistance.

  1. Hybrid Baryons

    CERN Document Server

    Page, P R

    2003-01-01

    We review the status of hybrid baryons. The only known way to study hybrids rigorously is via excited adiabatic potentials. Hybrids can be modelled by both the bag and flux-tube models. The low-lying hybrid baryon is N 1/2^+ with a mass of 1.5-1.8 GeV. Hybrid baryons can be produced in the glue-rich processes of diffractive gamma N and pi N production, Psi decays and p pbar annihilation.

  2. Analysis of gene expression during flowering in apomeiotic mutants of Medicago spp.: cloning of ESTs and candidate genes for 2n eggs.

    Science.gov (United States)

    Barcaccia, G; Varotto, S; Meneghetti, S; Albertini, E; Porceddu, A; Parrini, P; Lucchin, M

    2001-12-01

    Mutants showing features of apomixis have been documented in alfalfa (Medicago sativa L.), a natural outcrossing sexual species. A differential display of mRNAs that combines cDNA-AFLP markers and bulked segregant analysis was carried out with the aim of selecting expressed sequence tags (ESTs) and cloning candidate genes for apomeiosis in mutants of alfalfa characterized by 2n egg formation at high frequencies. The approach enabled us to select either mutant- or wild type-specific transcript derived-fragments and to detect transcriptional changes potentially related to 2n eggs. Sequence alignments of a subset of 40 polymorphic clones showed significant homologies to genes of known function. An EST with identity to a β-tubulin gene, highly expressed in the wild type and poorly expressed in the apomeiotic mutants, and an EST with identity to a Mob1-like gene, qualitatively polymorphic between pre- and post-meiotic stages, were selected as candidate genes for apomeiosis because of their putative roles in the cell cycle. A number of clone-specific primers were designed for performing both 5' and 3' rapid amplification of cDNA ends to obtain the full-length clones. Southern blot hybridization revealed that both clones belong to a multi-gene family with a minimum of three genomic DNA members each. Northern blot hybridization of total RNA samples and in situ hybridization of whole buds enabled the definition of their temporal and spatial expression patterns in reproductive organs. Experimental achievements towards the elucidation of apomeiotic megasporogenesis in alfalfa are presented and discussed.

  3. The new Center of Competence 'Compressed Air' at the Lucerne School of Engineering and Architecture; Aufbau des Druckluft-Kompetenzzentrums an der HTA Luzern. Phase 1

    Energy Technology Data Exchange (ETDEWEB)

    Stadelmann, B.

    2006-07-01

    The Lucerne School of Engineering and Architecture was commissioned by the Swiss Federal Office of Energy in 2004 to establish (in a first phase) a Center of Competence 'Compressed Air'. The project aimed at assessing the potential improvements of compressed air systems in operation. The Center of Competence 'Compressed Air' was to be promoted through publications in professional journals and users alerted to the inefficiency of compressed air systems. Tests were performed on-site on six compressed air systems, focussing on the compressed air distribution lines. The analyses showed that while the compressed air generated in one small system did little more than cover the losses in its distribution system, leakages in the other systems were less serious. Nevertheless, all of the systems showed potential improvements, though pressure losses in all systems were acceptable. The project has raised the awareness of users of compressed air and contributed to the development of energy-efficient compressed air systems. The Swiss Federal Office of Energy's campaign 'Druckluft Schweiz' will continue with these efforts, further promoting efficient energy use. (author)

  4. The succinoglycan endoglycanase encoded by exoK is required for efficient symbiosis of Sinorhizobium meliloti 1021 with the host plants Medicago truncatula and Medicago sativa (Alfalfa).

    Science.gov (United States)

    Mendis, Hajeewaka C; Queiroux, Clothilde; Brewer, Tess E; Davis, Olivia M; Washburn, Brian K; Jones, Kathryn M

    2013-09-01

    The acidic polysaccharide succinoglycan produced by the nitrogen-fixing rhizobial symbiont Sinorhizobium meliloti 1021 is required for this bacterium to invade the host plant Medicago truncatula and to efficiently invade the host plant M. sativa (alfalfa). The β-glucanase enzyme encoded by exoK has previously been demonstrated to cleave succinoglycan and participate in producing the low molecular weight form of this polysaccharide. Here, we show that exoK is required for efficient S. meliloti invasion of both M. truncatula and alfalfa. Deletion mutants of exoK have a substantial reduction in symbiotic productivity on both of these plant hosts. Insertion mutants of exoK have an even less productive symbiosis than the deletion mutants with the host M. truncatula that is caused by a secondary effect of the insertion itself, and may be due to a polar effect on the expression of the downstream exoLAMON genes.

  5. [Natural nucleotide polymorphism of the Srlk gene that determines salt stress tolerance in alfalfa (Medicago sativa L)].

    Science.gov (United States)

    Vishnevskaia, M S; Pavlov, A V; Dziubenko, E A; Dziubenko, N I; Potokina, E K

    2014-04-01

    Based on legume genome syntheny, the nucleotide sequence of Srlk gene, key role of which in response to salt stress was demonstrated for the model species Medicago truncatula, was identified in the major forage and siderate crop alfalfa (Medicago sativa). In twelve alfalfa samples originating from regions with contrasting growing conditions, 19 SNPs were revealed in the Srlk gene. For two nonsynonymous SNPs, molecular markers were designed that could be further used to analyze the association between Srlk gene nucleotide polymorphism and the variability in salt stress tolerance among alfalfa cultivars.

  6. Effects of Alfalfa on Fattening Performance of Hybrid Pigs in High Cold Mountain Area%紫花苜蓿对高寒山区杂交猪育肥性能的影响

    Institute of Scientific and Technical Information of China (English)

    钱龙; 王嘉福; 杨正德; 燕志宏; 林家栋

    2012-01-01

    试验选择大白猪(加×美)二元杂种猪24头(仔猪3~4周龄断奶,保育到8周龄),随机分为对照组、苜蓿Ⅰ组和苜蓿Ⅱ组,每组8头,分别饲喂基础日粮、基础日粮+3%苜蓿、基础日粮+6%苜蓿,试验期内在同一条件下进行饲养试验对其育肥性能、屠宰测定及肉质品质进行测定。试验结果表明:苜蓿Ⅰ组能够提高外二元猪育肥效果,苜蓿Ⅰ组和苜蓿Ⅱ组对背膘厚和皮厚也略有降低,添加3%和6%的苜蓿对其他屠宰性能及肉质品质影响不显著(P〉0.05)。由试验结果得出,在毕节高寒地区可以利用添加3%苜蓿比例的饲料对外二元杂交猪进行育肥。%In this study,24 binary hybrid pigs( D × Y) about 8 weeks were chosen, and they were randomly allocated into three dietary treatments : control group (basic diet), Medicago sativa group Ⅰ (basic diet + 3 % Medicago sativa), Medicago sativa group Ⅱ (basic diet + 3% Medicago sativa), except the diet, the pigs were fed in the same condition. After 98 days, the Fattening and Slaughtered performances were measured. The results showed that the Medieago sativa group Ⅰ improved the fattening performances, Medicago sativa group I and Medicago sativa group Ⅱ reduced baekfat thickness and skin thickness a little, to added 3 % and 6 % Medicago sativa into the basic diet had no significant influence on the othcr fattening and slaughtered performances. So we concluded that to add 3% Medicago sativa into the basicdiet to fatten the binary hybrid pig in the alpine region of Bijie was feasible.

  7. Genomic characterization of the LEED..PEEDs, a gene family unique to the medicago lineage.

    Science.gov (United States)

    Trujillo, Diana I; Silverstein, Kevin A T; Young, Nevin D

    2014-08-25

    The LEED..PEED (LP) gene family in Medicago truncatula (A17) is composed of 13 genes coding small putatively secreted peptides with one to two conserved domains of negatively charged residues. This family is not present in the genomes of Glycine max, Lotus japonicus, or the IRLC species Cicer arietinum. LP genes were also not detected in a Trifolium pratense draft genome or Pisum sativum nodule transcriptome, which were sequenced de novo in this study, suggesting that the LP gene family arose within the past 25 million years. M. truncatula accession HM056 has 13 LP genes with high similarity to those in A17, whereas M. truncatula ssp. tricycla (R108) and M. sativa have 11 and 10 LP gene copies, respectively. In M. truncatula A17, 12 LP genes are located on chromosome 7 within a 93-kb window, whereas one LP gene copy is located on chromosome 4. A phylogenetic analysis of the gene family is consistent with most gene duplications occurring prior to Medicago speciation events, mainly through local tandem duplications and one distant duplication across chromosomes. Synteny comparisons between R108 and A17 confirm that gene order is conserved between the two subspecies, although a further duplication occurred solely in A17. In M. truncatula A17, all 13 LPs are exclusively transcribed in nodules and absent from other plant tissues, including roots, leaves, flowers, seeds, seed shells, and pods. The recent expansion of LP genes in Medicago spp. and their timing and location of expression suggest a novel function in nodulation, possibly as an aftermath of the evolution of bacteroid terminal differentiation or potentially associated with rhizobial-host specificity.

  8. Hybrid vehicles

    Energy Technology Data Exchange (ETDEWEB)

    West, J.G.W. [Electrical Machines (United Kingdom)

    1997-07-01

    The reasons for adopting hybrid vehicles result mainly from the lack of adequate range from electric vehicles at an acceptable cost. Hybrids can offer significant improvements in emissions and fuel economy. Series and parallel hybrids are compared. A combination of series and parallel operation would be the ideal. This can be obtained using a planetary gearbox as a power split device allowing a small generator to transfer power to the propulsion motor giving the effect of a CVT. It allows the engine to run at semi-constant speed giving better fuel economy and reduced emissions. Hybrid car developments are described that show the wide range of possible hybrid systems. (author)

  9. Effect of salt stress on germination and enzyme activity in two genotypes of Medicago sativa

    OpenAIRE

    Ilyess Lachhab; Said Louahlia; Meryem Laamarti; Khalil Hammani

    2013-01-01

    The arid and semi-arid represent one third of the earth's surface. In these areas, soil salinity and irrigation water is one of the limiting factors for plant productivity and crop yields. These ecosystems are characterized by a high variability of rainfall combined with high evaporation favoring the accumulation of salts in the soil. This affects about 7% of the total area in the world. Germination of Medicago sativa is inhibited by 1.5% NaCl (260 mmol/l). Sodium chloride (NaCl) salinity is ...

  10. Studies on Medicago lupulina saponins. 6. Some chemical characteristics and biological activity of root saponins

    Directory of Open Access Journals (Sweden)

    Wiesław Oleszek

    2014-01-01

    Full Text Available The saponin fraction of black medic trefoil (Medicago lupulina roots was isolated and purified. Its hydrolysis afforded several aglycones that have been identified by spectral and chemical properties as medicagenic acid, hederagenine and soyasapogenols: B, C, D, E and F. They made up, respectively. 46.9 and 45% of total sapogenins isolated. Two-dimensional TLC of M. lupulina root saponins revealed fourteen compounds, two of which were medicagenic acid glycosides. The haemolytic, antifungal and allelopathic activities of M. lupulina and M. media roots are compared and discussed.

  11. Chemical characterisation of bioactive compounds in Medicago sativa growing in the desert of Oman.

    Science.gov (United States)

    Hanif, Muhammad Asif; Al-Maskari, Ahmed Yahya; Al-Sabahi, Jamal Nasser; Al-Hdhrami, Ibtisam; Khan, Muhammad Mumtaz; Al-Azkawi, Ahlam; Hussain, Abdullah Ijaz

    2015-01-01

    Medicago sativa Linn growing in Omani desert were chemically characterised using flame photometry, inductively coupled plasma, gas chromatography-mass spectrometry and high performance liquid chromatographic (HPLC) analysis. HPLC analyses were performed to determine the phenolics and flavonoids present in M. sativa. The major compounds detected in M. sativa leaves were protchaechenic acid (3.22%), hydroxyl benzoic acid (1.05%), β-Phenyl caffate (0.97%) and kaempherol (0.89%). Pterostilbene, a cholesterol-lowering compound, was detected in M. sativa.

  12. CARACTERIZACIÓN AGROMORFOLOGICA Y CONTENIDO EN ADN NUCLEAR EN ACCESIONES DE CUATRO ESPECIES DE MEDICAGOS ANUALES DEL NORTE DE ESPAÑA

    OpenAIRE

    Oliveira Prendes, J. A.; Afif Khouri, E.

    2012-01-01

    Dieciséis accesiones anuales y autógamas de cuatro especies del género Medicago procedentes del norte de España se caracterizaron durante dos años (2008 y 2009) en un diseño por bloques aleatorizados completos con tres repeticiones de 10 plantas por accesión (en total 30 plantas por accesión). El cv Santiago de Medicago polymorpha y la accesión 3710 de Medicago arábica se incluyeron como testigos en el estudio. Todas las accesiones y los testigos se evaluaron mediante nueve caracteres agromor...

  13. CARACTERIZACIÓN AGROMORFOLOGICA Y CONTENIDO EN ADN NUCLEAR EN ACCESIONES DE CUATRO ESPECIES DE MEDICAGOS ANUALES DEL NORTE DE ESPAÑA

    OpenAIRE

    Oliveira Prendes, J. A.; AFIF KHOURI, E.

    2012-01-01

    Dieciséis accesiones anuales y autógamas de cuatro especies del género Medicago procedentes del norte de España se caracterizaron durante dos años (2008 y 2009) en un diseño por bloques aleatorizados completos con tres repeticiones de 10 plantas por accesión (en total 30 plantas por accesión). El cv Santiago de Medicago polymorpha y la accesión 3710 de Medicago arábica se incluyeron como testigos en el estudio. Todas las accesiones y los testigos se evaluaron mediante nueve caracteres agromor...

  14. Mycorrhiza symbiosis increases the surface for sunlight capture in Medicago truncatula for better photosynthetic production.

    Directory of Open Access Journals (Sweden)

    Lisa Adolfsson

    Full Text Available Arbuscular mycorrhizal (AM fungi play a prominent role in plant nutrition by supplying mineral nutrients, particularly inorganic phosphate (Pi, and also constitute an important carbon sink. AM stimulates plant growth and development, but the underlying mechanisms are not well understood. In this study, Medicago truncatula plants were grown with Rhizophagus irregularis BEG141 inoculum (AM, mock inoculum (control or with P(i fertilization. We hypothesized that AM stimulates plant growth through either modifications of leaf anatomy or photosynthetic activity per leaf area. We investigated whether these effects are shared with P(i fertilization, and also assessed the relationship between levels of AM colonization and these effects. We found that increased P(i supply by either mycorrhization or fertilization led to improved shoot growth associated with increased nitrogen uptake and carbon assimilation. Both mycorrhized and P(i-fertilized plants had more and longer branches with larger and thicker leaves than the control plants, resulting in an increased photosynthetically active area. AM-specific effects were earlier appearance of the first growth axes and increased number of chloroplasts per cell section, since they were not induced by P(i fertilization. Photosynthetic activity per leaf area remained the same regardless of type of treatment. In conclusion, the increase in growth of mycorrhized and P(i-fertilized Medicago truncatula plants is linked to an increase in the surface for sunlight capture, hence increasing their photosynthetic production, rather than to an increase in the photosynthetic activity per leaf area.

  15. Novel SINEs families in Medicago truncatula and Lotus japonicus: bioinformatic analysis.

    Science.gov (United States)

    Gadzalski, Marek; Sakowicz, Tomasz

    2011-07-01

    Although short interspersed elements (SINEs) were discovered nearly 30 years ago, the studies of these genomic repeats were mostly limited to animal genomes. Very little is known about SINEs in legumes--one of the most important plant families. Here we report identification, genomic distribution and molecular features of six novel SINE elements in Lotus japonicus (named LJ_SINE-1, -2, -3) and Medicago truncatula (MT_SINE-1, -2, -3), model species of legume. They possess all the structural features commonly found in short interspersed elements including RNA polymerase III promoter, polyA tail and flanking repeats. SINEs described here are present in low to moderate copy numbers from 150 to 3000. Bioinformatic analyses were used to searched public databases, we have shown that three of new SINE elements from M. truncatula seem to be characteristic of Medicago and Trifolium genera. Two SINE families have been found in L. japonicus and one is present in both M. truncatula and L. japonicus. In addition, we are discussing potential activities of the described elements. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Nitric oxide is formed in Medicago truncatula-Sinorhizobium meliloti functional nodules.

    Science.gov (United States)

    Baudouin, Emmanuel; Pieuchot, Laurent; Engler, Gilbert; Pauly, Nicolas; Puppo, Alain

    2006-09-01

    Nitric oxide (NO) has recently gained interest as a major signaling molecule during plant development and response to environmental cues. Its role is particularly crucial for plant-pathogen interactions, during which it participates in the control of plant defense response and resistance. Indication for the presence of NO during symbiotic interactions has also been reported. Here, we defined when and where NO is produced during Medicago truncatula-Sinorhizobium meliloti symbiosis. Using the NO-specific fluorescent probe 4,5-diaminofluorescein diacetate, NO production was detected by confocal microscopy in functional nodules. NO production was localized in the bacteroid-containing cells of the nodule fixation zone. The infection of Medicago roots with bacterial strains impaired in nitrogenase or nitrite reductase activities lead to the formation of nodules with an unaffected NO level, indicating that neither nitrogen fixation nor denitrification pathways are required for NO production. On the other hand, the NO synthase inhibitor N-methyl-L-arginine impaired NO detection, suggesting that a NO synthase may participate to NO production in nodules. These data indicate that a NO production occurs in functional nodules. The location of such a production in fully metabolically active cells raises the hypothesis of a new function for NO during this interaction unrelated to defense and cell-death activation.

  17. Characterization and genetic dissection of resistance to spotted alfalfa aphid (Therioaphis trifolii) in Medicago truncatula

    KAUST Repository

    Kamphuis, L. G.

    2013-09-21

    Aphids cause significant yield losses in agricultural crops worldwide. Medicago truncatula, a model legume, cultivated pasture species in Australia and close relative of alfalfa (Medicago sativa), was used to study the defence response against Therioaphis trifolii f. maculate [spotted alfalfa aphid (SAA)]. Aphid performance and plant damage were compared among three accessions. A20 is highly susceptible, A17 has moderate resistance, and Jester is strongly resistant. Subsequent analyses using A17 and A20, reciprocal F1s and an A17×A20 recombinant inbred line (RIL) population revealed that this moderate resistance is phloem mediated and involves antibiosis and tolerance but not antixenosis. Electrical penetration graph analysis also identified a novel waveform termed extended potential drop, which occurred following SAA infestation of M. truncatula. Genetic dissection using the RIL population revealed three quantitative trait loci on chromosomes 3, 6, and 7 involved in distinct modes of aphid defence including antibiosis and tolerance. An antibiosis locus resides on linkage group 3 (LG3) and is derived from A17, whereas a plant tolerance and antibiosis locus resides on LG6 and is derived from A20, which exhibits strong temporary tolerance. The loci identified reside in regions harbouring classical resistance genes, and introgression of these loci in current medic cultivars may help provide durable resistance to SAA, while elucidation of their molecular mechanisms may provide valuable insight into other aphid–plant interactions.

  18. Mycorrhiza symbiosis increases the surface for sunlight capture in Medicago truncatula for better photosynthetic production.

    Science.gov (United States)

    Adolfsson, Lisa; Solymosi, Katalin; Andersson, Mats X; Keresztes, Áron; Uddling, Johan; Schoefs, Benoît; Spetea, Cornelia

    2015-01-01

    Arbuscular mycorrhizal (AM) fungi play a prominent role in plant nutrition by supplying mineral nutrients, particularly inorganic phosphate (Pi), and also constitute an important carbon sink. AM stimulates plant growth and development, but the underlying mechanisms are not well understood. In this study, Medicago truncatula plants were grown with Rhizophagus irregularis BEG141 inoculum (AM), mock inoculum (control) or with P(i) fertilization. We hypothesized that AM stimulates plant growth through either modifications of leaf anatomy or photosynthetic activity per leaf area. We investigated whether these effects are shared with P(i) fertilization, and also assessed the relationship between levels of AM colonization and these effects. We found that increased P(i) supply by either mycorrhization or fertilization led to improved shoot growth associated with increased nitrogen uptake and carbon assimilation. Both mycorrhized and P(i)-fertilized plants had more and longer branches with larger and thicker leaves than the control plants, resulting in an increased photosynthetically active area. AM-specific effects were earlier appearance of the first growth axes and increased number of chloroplasts per cell section, since they were not induced by P(i) fertilization. Photosynthetic activity per leaf area remained the same regardless of type of treatment. In conclusion, the increase in growth of mycorrhized and P(i)-fertilized Medicago truncatula plants is linked to an increase in the surface for sunlight capture, hence increasing their photosynthetic production, rather than to an increase in the photosynthetic activity per leaf area.

  19. Modulation of endogenous indole-3-acetic acid biosynthesis in bacteroids within Medicago sativa nodules.

    Science.gov (United States)

    Bianco, C; Senatore, B; Arbucci, S; Pieraccini, G; Defez, R

    2014-07-01

    To evaluate the dose-response effects of endogenous indole-3-acetic acid (IAA) on Medicago plant growth and dry weight production, we increased the synthesis of IAA in both free-living and symbiosis-stage rhizobial bacteroids during Rhizobium-legume symbiosis. For this purpose, site-directed mutagenesis was applied to modify an 85-bp promoter sequence, driving the expression of iaaM and tms2 genes for IAA biosynthesis. A positive correlation was found between the higher expression of IAA biosynthetic genes in free-living bacteria and the increased production of IAA under both free-living and symbiotic conditions. Plants nodulated by RD65 and RD66 strains, synthetizing the highest IAA concentration, showed a significant (up to 73%) increase in the shoot fresh weight and upregulation of nitrogenase gene, nifH, compared to plants nodulated by the wild-type strain. When these plants were analyzed by confocal microscopy, using an anti-IAA antibody, the strongest signal was observed in bacteroids of Medicago sativa RD66 (Ms-RD66) plants, even when they were located in the senescent nodule zone. We show here a simple system to modulate endogenous IAA biosynthesis in bacteria nodulating legumes suitable to investigate which is the maximum level of IAA biosynthesis, resulting in the maximal increase of plant growth.

  20. The Medicago truncatula lysine motif-receptor-like kinase gene family includes NFP and new nodule-expressed genes

    NARCIS (Netherlands)

    Arrighi, J.F.; Barre, A.; Amor, Ben B.; Bersoult, A.; Campos Soriano, L.; Mirabella, R.; Carvalho-Niebel, de F.; Journet, E.P.; Ghérardi, M.; Huguet, T.; Geurts, R.; Dénarié, J.; Rougé, P.; Gough, C.

    2006-01-01

    Rhizobial Nod factors are key symbiotic signals responsible for starting the nodulation process in host legume plants. Of the six Medicago truncatula genes controlling a Nod factor signaling pathway, Nod Factor Perception (NFP) was reported as a candidate Nod factor receptor gene. Here, we provide

  1. Thiaminase activities and thiamine content of Pteridium aquilinum, Equisetum ramosissimum, Malva parviflora, Pennisetum clandestinum and Medicago sativa.

    Science.gov (United States)

    Meyer, P

    1989-06-01

    Thiaminase type 1 and 2 activities and thiamine content of five plants were determined. Of these Pteridium aquilinum and Equisetum ramosissimum were found to have considerably more thiaminase activity and lower thiamine content than Malva parviflora, Pennisetum clandestinum and Medicago sativa.

  2. Effect of wheel traffic and green manure treatments on forage yield and crown rot in alfalfa (Medicago sativa)

    Science.gov (United States)

    Harvesting alfalfa (Medicago sativa) results in mechanical wheel traffic on plants, which may damage crowns and increase the opportunity for entry of pathogens causing crown rot. Developing resistance to crown rot is problematic due to the large number of pathogens involved. Incorporation of plant b...

  3. Expression of the Sinorhizobium meliloti C4-dicarboxylate transport gene during symbiosis with the Medicago host plant

    NARCIS (Netherlands)

    Boesten, B.

    1999-01-01

    During symbiosis between Sinorhizobium meliloti and the Medicago host plant, the energy required to fix atmospheric nitrogen, is derived from the plant photosynthate. Current evidence indicates that C 4 -dicarboxylates (dCA) are the major and probably only source of carbon provided to the

  4. ECOLOGICAL RISK ASSESSMENT OF ALFALFA (MEDICAGO VARIA L.) GENETICLALY ENGINEERED TO EXPRESS A HUMAN METALLOTHIONEIN (HMT) GENE

    Science.gov (United States)

    The objectives of these studies were two-fold: (1) to determine efficacy of low and high expression hMT gene constructs by assessing accumulation of Cu in shoots of parental and transgenic plants of alfalfa (Medicago varia L.) exposed to different concentrations of CuSO4 by addit...

  5. Leaf calcium oxalate crystal structure and its role in defense against a chewing insect in Medicago truncatula

    Science.gov (United States)

    Crystals of calcium oxalate are common in plants and widely distributed among many plant families. These hard and largely insoluble crystals take on many shapes and sizes depending on the tissue and species. In Medicago truncatula, calcium oxalate crystals are abundant in leaves and accumulate in sh...

  6. Contrasting calcium localization and speciation in leaves of Medicago trunculata mutant COD5 analyzed via synchrotron X-ray techniques

    Science.gov (United States)

    Oxalate-producing plants accumulate calcium oxalate crystals (CaOx(C)) in the range of 3-80%(w/w) of their dry weight, reducing calcium (Ca) bioavailability. The calcium oxalate deficient 5 (cod5) mutant of Medicago truncatula has been previously shown to contain similar Ca, but lower oxalate and Ca...

  7. Effect of alfalfa (medicago sativa) on fermentation profile and nutritive value of switchgrass (panicum virgatum) and bermudagrass (cynodon dactylon) silages

    Science.gov (United States)

    An experiment was conducted at the University of Kentucky Spindletop Farm in Lexington, Kentucky between October and November, 2009 to evaluate the effect of different percentages of alfalfa (Medicago sativa) as mixtures in switchgrass (Panicum virgatus) and bermudagrass (Cynodon dactylon) silages. ...

  8. Application of Multilocus Sequence Typing To Study the Genetic Structure of Megaplasmids in Medicago-Nodulating Rhizobia

    Science.gov (United States)

    A multilocus sequence typing (MLST) analysis was used to examine the relatedness and distribution of genotypic variants of the two large extrachromosomal replicons in Medicago-nodulating rhizobia (Sinorhizobium meliloti and S. medicae). One goal was to develop a strategy for the characterization of...

  9.  Molecular evolution and positive selection of the symbiotic gene NORK in Medicago truncatula

    DEFF Research Database (Denmark)

    De Mita, Stephane; Santoni, Sylvain; Hochu, Isabelle

    2006-01-01

    . The membrane-anchored receptor NORK (nodulation receptor kinase) of the legume Medicago truncatula controls early steps of root infection by two symbiotic microorganisms: nitrogen-fixing bacteria (rhizobia) and endomycorrhizal fungi (Glomales). We analyzed the diversity of the gene NORK by sequencing 4...

  10. The Medicago truncatula lysine motif-receptor-like kinase gene family includes NFP and new nodule-expressed genes

    NARCIS (Netherlands)

    Arrighi, J.F.; Barre, A.; Amor, Ben B.; Bersoult, A.; Campos Soriano, L.; Mirabella, R.; Carvalho-Niebel, de F.; Journet, E.P.; Ghérardi, M.; Huguet, T.; Geurts, R.; Dénarié, J.; Rougé, P.; Gough, C.

    2006-01-01

    Rhizobial Nod factors are key symbiotic signals responsible for starting the nodulation process in host legume plants. Of the six Medicago truncatula genes controlling a Nod factor signaling pathway, Nod Factor Perception (NFP) was reported as a candidate Nod factor receptor gene. Here, we provide f

  11. Fractionation of Synteny in a Genomic Region Containing Tandemly Duplicated Genes Across Glycine max, Medicago truncatula and Arabidopsis thaliana

    Science.gov (United States)

    Extended comparison of gene sequences found on homeologous soybean BACs to Medicago truncatula and Arabidopsis thaliana genomic sequences demonstrated a network of synteny within conserved regions interrupted by gene addition and/or deletions. Consolidation of gene order among all three species prov...

  12. A sequence-based genetic map of Medicago truncatula and comparison of marker colinearity with M. sativa

    NARCIS (Netherlands)

    Choi, H.K.; Kim, D.; Uhm, T.; Limpens, E.H.M.; Lim, H.; Mun, J.H.; Kalo, P.; Penmetsa, R.V.; Seres, A.; Kulikova, O.; Roe, B.A.; Bisseling, T.; Kiss, G.B.; Cook, D.R.

    2004-01-01

    A core genetic map of the legume Medicago truncatula has been established by analyzing the segregation of 288 sequence-characterized genetic markers in an E, population composed of 93 individuals. These molecular markers correspond to 141 ESTs, 80 BAC end sequence tags, and 67 resistance gene analog

  13. Detection of QTL for forage yield, lodging resistance and spring vigor traits in alfalfa (Medicago sativa L.)

    Science.gov (United States)

    Alfalfa (Medicago sativa L.) is an internationally significant forage crop. Forage yield, lodging resistance and spring vigor are important agronomic traits conditioned by quantitative genetic and environmental effects. The objective of this study was to identify quantitative trait loci (QTL) and mo...

  14. ECOLOGICAL RISK ASSESSMENT OF ALFALFA (MEDICAGO VARIA L.) GENETICLALY ENGINEERED TO EXPRESS A HUMAN METALLOTHIONEIN (HMT) GENE

    Science.gov (United States)

    The objectives of these studies were two-fold: (1) to determine efficacy of low and high expression hMT gene constructs by assessing accumulation of Cu in shoots of parental and transgenic plants of alfalfa (Medicago varia L.) exposed to different concentrations of CuSO4 by addit...

  15. Medicago truncatula-derived calcium oxalate crystals have a negative impact on chewing insect performance via their physical properties

    Science.gov (United States)

    Plant structural traits often act as defenses against herbivorous insects, causing them to avoid feeding on a given plant or tissue. Mineral crystals of calcium oxalate in Medicago truncatula Gaertn. (Fabaceae) leaves have previously been shown to be effective deterrents of lepidopteran insect feedi...

  16. 不同品种紫花苜蓿(Medicago sativa)的化感效应研究%Study on Allelopathy of Medicago sativa Stem Aqueous extracts

    Institute of Scientific and Technical Information of China (English)

    董晓宁; 高承芳; 李文杨; 张晓佩

    2009-01-01

    用砂培法研究紫花苜蓿(Medicago sativa)的六个品种苗期地上部分水浸提液对鸭茅(Dactylis glomerata L.)的化感效应.结果表明,紫花苜蓿六个品种茎叶水浸提液对鸭茅的化感效应在供试品种间差异显著.游客、苜蓿对鸭茅的种子发芽及幼苗生长有抑制作用,但游客却对鸭茅的苗干重有促进作用;三得利和赛迪对鸭茅的种子发芽、根长及根干重有抑制作用,却对苗生长的影响无显著差异.此外,供试紫花苜蓿浸提液对鸭茅的化感作用,随着浓度的升高,抑制作用随之增强.

  17. Effect of UV-C on Drought Tolerance of Alfalfa (Medicago sativa Callus

    Directory of Open Access Journals (Sweden)

    Ali A. Ehsanpour

    2005-01-01

    Full Text Available Water stress and unfavorable climate decrease the growth and development of plant globally. Medicago is a valuable plant as a source of food for animal, foliage and for medicine. Since, Iran is located in a dry area; consequently, the study of plant responses to water stress is important. In this research UV-C radiation was used to induce physiological and genetic changes in alfalfa callus. In vitro grown calluses of M. sativa were exposed to UV-C for 0, 15, 30 and 60 min and then, were transferred to MS medium containing 0, 2, 5, 10, 20, 30% PEG. All explants were kept in the dark in the culture room. Calluses tolerate to osmotic stress were selected according to fresh weight. Results showed that radiation of UV-C for 60 min increased the osmotic tolerance and decreased the effect of drought stress.

  18. Regulation of symbiotic nitrogen fixation in root nodules of alfalfa (Medicago sativa) infected with Rhizobium meliloti.

    Science.gov (United States)

    Kamberger, W

    1977-10-24

    Symbiotic nitrogen fixation of Rhizobium meliloti bacteroids in Medicago sativa root nodules was suppressed by several inorganic nitrogen sources. Amino acids like glutamine, glutamic acid and aspartic acid, which can serve as sole nitrogen sources for the unnodulated plant did not influence nitrogenase activity of effective nodules, even at high concetrations. Ammonia and nitrate suppressed symbiotic nitrogen fixation in vivo only at concentrations much higher than those needed for suppression of nitrogenase activity in free living nitrogen fixing bacteria. The kinetics of suppression were slow compared with that of free living nitrogen fixing bacteria. On the other hand, nitrite, which acts as a direct inhibitor of nitrogenase, suppressed very quickly and at low concentrations. Glutamic acid and glutamine enhanced the effect of ammonia dramatically, while the suppression by nitrate was enhanced only slightly.

  19. [Control of the fermentation activity during ensilage of Lolium italicum A. Br. and Medicago sativa L].

    Science.gov (United States)

    Ozino Marletto, O I; Ambrosoli, R; Piccone, G; Biasiol, B

    1982-01-01

    Samples with different dry matter contents of Lolium italicum A. Br., Medicago sativa L., have been ensiled in hermetically sealed containers, in order to study the evolution of microflora and its activity. The principal microbial groups (coliforms, proteolytics , lactic acid bacteria, clostridia, yeasts) have been detected and enumerated, in anaerobic atmosphere, after ensiling periods of 3, 6, 10, 13, 20, 100 days. At the same time, the samples were chemically analyzed for the detection of: pH, moisture, ashes, total and ammoniacal nitrogen, total reducing sugars, lactic acid, volatile fatty acids, short chain alcohols. The relations found between chemical and microbiological data, show that a strong lactic fermentation is not enough for the inhibition of silage spoiling microorganisms, such as coliforms, yeasts, and (less) proteolytics . This phenomenon may be related to the "quality" of the lactic acid microflora, more than to the characteristics of the environment.

  20. Transcriptomic Analysis of Sinorhizobium meliloti and Medicago truncatula Symbiosis Using Nitrogen Fixation-Deficient Nodules.

    Science.gov (United States)

    Lang, Claus; Long, Sharon R

    2015-08-01

    The bacterium Sinorhizobium meliloti interacts symbiotically with legume plant hosts such as Medicago truncatula to form nitrogen-fixing root nodules. During symbiosis, plant and bacterial cells differentiate in a coordinated manner, resulting in specialized plant cells that contain nitrogen-fixing bacteroids. Both plant and bacterial genes are required at each developmental stage of symbiosis. We analyzed gene expression in nodules formed by wild-type bacteria on six plant mutants with defects in nitrogen fixation. We observed differential expression of 482 S. meliloti genes with functions in cell envelope homeostasis, cell division, stress response, energy metabolism, and nitrogen fixation. We simultaneously analyzed gene expression in M. truncatula and observed differential regulation of host processes that may trigger bacteroid differentiation and control bacterial infection. Our analyses of developmentally arrested plant mutants indicate that plants use distinct means to control bacterial infection during early and late symbiotic stages.

  1. Soil decontamination of 2,4,6- trinitrotoluene by alfalfa (Medicago sativa).

    Science.gov (United States)

    Fallahi, S; Habibi-Rezaei, M; Khayami, M; Heydari, R

    2007-12-15

    Present study investigate the toxicity effect of 2,4,6-trinitrotoluene (TNT) on a terrestrial plant, alfalfa (Medicago sativa) in artificial soils. In this study, TNT toxicity assessment was performed on spiked silica with this nitroaromatic compound by determination of the percent of emergence and shoots and roots biomasses at the concentration range of 3.2-10000 mg kg(-1) Dry Weight (DW). The emergence was reduced by 22-32% after 5 days of exposure at TNT concentrations up to 100 mg kg(-1) DW; shoot and root biomasses were reduced by 48-50 and 63-74%, respectively after 30 days exposure at TNT concentrations alfalfa cultivation for 30 days, TNT was partially transformed at the extent of 15-27%. This transformation decreased at higher TNT soil concentrations. TNT is taken up and metabolized by plants to its downstream derivatives.

  2. Alteration of enod40 expression modifies medicago truncatula root nodule development induced by sinorhizobium meliloti

    Science.gov (United States)

    Charon, C; Sousa, C; Crespi, M; Kondorosi, A

    1999-01-01

    Molecular mechanisms involved in the control of root nodule organogenesis in the plant host are poorly understood. One of the nodulin genes associated with the earliest phases of this developmental program is enod40. We show here that transgenic Medicago truncatula plants overexpressing enod40 exhibit accelerated nodulation induced by Sinorhizobium meliloti. This resulted from increased initiation of primordia, which was accompanied by a proliferation response of the region close to the root tip and enhanced root length. The root cortex of the enod40-transformed plants showed increased sensitivity to nodulation signals. T(1) and T(2) descendants of two transgenic lines with reduced amounts of enod40 transcripts (probably from cosuppression) formed only a few and modified nodulelike structures. Our results suggest that induction of enod40 is a limiting step in primordium formation, and its function is required for appropriate nodule development. PMID:10521525

  3. [Effects of copper stress on Medicago sativa seedlings leaf antioxidative system].

    Science.gov (United States)

    Wang, Song-hua; Zhang, Hua; He, Qing-yuan

    2011-09-01

    This paper studied the effects of different concentration (0, 10, 30, 50, and 100 micromol x L(-1)) CuSO4 on the leaf physiological and biochemical characteristics of Medicago sativa seedlings cultured with 1/4-strength Hoagland nutrient solution. In treatments 30, 50, and 100 micromol x L(-1) of CuSO4, the leaf H2O2, OH., and MDA contents and Fe-SOD and EST activities increased, and GSH and AsA contents increased significantly. With increasing concentration Cu, the POD, GR, and APX activities increased gradually, and the CAT and G6PDH activities decreased after an initial increase. In treatments >10 micromol x L(-1) of Cu, the capacity of leaf antioxidative system in reactive oxygen species scavenging increased to prevent the injury from copper-induced oxidative stress.

  4. Triterpenoid glycosides from Medicago sativa as antifungal agents against Pyricularia oryzae.

    Science.gov (United States)

    Abbruscato, Pamela; Tosi, Solveig; Crispino, Laura; Biazzi, Elisa; Menin, Barbara; Picco, Anna M; Pecetti, Luciano; Avato, Pinarosa; Tava, Aldo

    2014-11-19

    The antifungal properties of saponin mixtures from alfalfa (Medicago sativa L.) tops and roots, the corresponding mixtures of prosapogenins from tops, and purified saponins and sapogenins against the causal agent of rice blast Pyricularia oryzae isolates are presented. In vitro experiments highlighted a range of activities, depending upon the assayed metabolite. The antifungal effects of the most promising prosapogenin mixture from alfalfa tops were confirmed by means of in planta tests using three different Italian cultivars of rice (Oryza sativa L. ssp. japonica), known to possess high, medium, and low blast resistance. The evidenced antifungal properties of the tested metabolites allowed some considerations on their structure-activity relationship. Results indicate that prosapogenins are active compounds to prevent the fungal attack of P. oryzae on different rice cultivars. Therefore, if properly formulated, these substances could represent a promising and environmentally friendly treatment to control rice blast.

  5. Hybrid Metaheuristics

    CERN Document Server

    2013-01-01

    The main goal of this book is to provide a state of the art of hybrid metaheuristics. The book provides a complete background that enables readers to design and implement hybrid metaheuristics to solve complex optimization problems (continuous/discrete, mono-objective/multi-objective, optimization under uncertainty) in a diverse range of application domains. Readers learn to solve large scale problems quickly and efficiently combining metaheuristics with complementary metaheuristics, mathematical programming, constraint programming and machine learning. Numerous real-world examples of problems and solutions demonstrate how hybrid metaheuristics are applied in such fields as networks, logistics and transportation, bio-medical, engineering design, scheduling.

  6. Evolutionary history of mitogen-activated protein kinase (MAPK) genes in Lotus, Medicago, and Phaseolus.

    Science.gov (United States)

    Neupane, Achal; Nepal, Madhav P; Benson, Benjamin V; Macarthur, Kenton J; Piya, Sarbottam

    2013-11-01

    Mitogen-Activated Protein Kinase (MAPK) genes encode proteins that mediate various signaling pathways associated with biotic and abiotic stress responses in eukaryotes. The MAPK genes form a 3-tier signal transduction cascade between cellular stimuli and physiological responses. Recent identification of soybean MAPKs and availability of genome sequences from other legume species allowed us to identify their MAPK genes. The main objectives of this study were to identify MAPKs in 3 legume species, Lotus japonicus, Medicago truncatula, and Phaseolus vulgaris, and to assess their phylogenetic relationships. We used approaches in comparative genomics for MAPK gene identification and named the newly identified genes following Arabidopsis MAPK nomenclature model. We identified 19, 18, and 15 MAPKs and 7, 4, and 9 MAPKKs in the genome of Lotus japonicus, Medicago truncatula, and Phaseolus vulgaris, respectively. Within clade placement of MAPKs and MAPKKs in the 3 legume species were consistent with those in soybean and Arabidopsis. Among 5 clades of MAPKs, 4 founder clades were consistent to MAPKs of other plant species and orthologs of MAPK genes in the fifth clade-"Clade E" were consistent with those in soybean. Our results also indicated that some gene duplication events might have occurred prior to eudicot-monocot divergence. Highly diversified MAPKs in soybean relative to those in 3 other legume species are attributable to the polyploidization events in soybean. The identification of the MAPK genes in the legume species is important for the legume crop improvement; and evolutionary relationships and functional divergence of these gene members provide insights into plant genome evolution.

  7. An expression database for roots of the model legume Medicago truncatula under salt stress

    Directory of Open Access Journals (Sweden)

    Dong Jiangli

    2009-11-01

    Full Text Available Abstract Background Medicago truncatula is a model legume whose genome is currently being sequenced by an international consortium. Abiotic stresses such as salt stress limit plant growth and crop productivity, including those of legumes. We anticipate that studies on M. truncatula will shed light on other economically important legumes across the world. Here, we report the development of a database called MtED that contains gene expression profiles of the roots of M. truncatula based on time-course salt stress experiments using the Affymetrix Medicago GeneChip. Our hope is that MtED will provide information to assist in improving abiotic stress resistance in legumes. Description The results of our microarray experiment with roots of M. truncatula under 180 mM sodium chloride were deposited in the MtED database. Additionally, sequence and annotation information regarding microarray probe sets were included. MtED provides functional category analysis based on Gene and GeneBins Ontology, and other Web-based tools for querying and retrieving query results, browsing pathways and transcription factor families, showing metabolic maps, and comparing and visualizing expression profiles. Utilities like mapping probe sets to genome of M. truncatula and In-Silico PCR were implemented by BLAT software suite, which were also available through MtED database. Conclusion MtED was built in the PHP script language and as a MySQL relational database system on a Linux server. It has an integrated Web interface, which facilitates ready examination and interpretation of the results of microarray experiments. It is intended to help in selecting gene markers to improve abiotic stress resistance in legumes. MtED is available at http://bioinformatics.cau.edu.cn/MtED/.

  8. Contrasted patterns of selective pressure in three recent paralogous gene pairs in the Medicago genus (L.

    Directory of Open Access Journals (Sweden)

    Ho-Huu Joan

    2012-10-01

    Full Text Available Abstract Background Gene duplications are a molecular mechanism potentially mediating generation of functional novelty. However, the probabilities of maintenance and functional divergence of duplicated genes are shaped by selective pressures acting on gene copies immediately after the duplication event. The ratio of non-synonymous to synonymous substitution rates in protein-coding sequences provides a means to investigate selective pressures based on genic sequences. Three molecular signatures can reveal early stages of functional divergence between gene copies: change in the level of purifying selection between paralogous genes, occurrence of positive selection, and transient relaxed purifying selection following gene duplication. We studied three pairs of genes that are known to be involved in an interaction with symbiotic bacteria and were recently duplicated in the history of the Medicago genus (Fabaceae. We sequenced two pairs of polygalacturonase genes (Pg11-Pg3 and Pg11a-Pg11c and one pair of auxine transporter-like genes (Lax2-Lax4 in 17 species belonging to the Medicago genus, and sought for molecular signatures of differentiation between copies. Results Selective histories revealed by these three signatures of molecular differentiation were found to be markedly different between each pair of paralogs. We found sites under positive selection in the Pg11 paralogs while Pg3 has mainly evolved under purifying selection. The most recent paralogs examined Pg11a and Pg11c, are both undergoing positive selection and might be acquiring new functions. Lax2 and Lax4 paralogs are both under strong purifying selection, but still underwent a temporary relaxation of purifying selection immediately after duplication. Conclusions This study illustrates the variety of selective pressures undergone by duplicated genes and the effect of age of the duplication. We found that relaxation of selective constraints immediately after duplication might promote

  9. Medicago truncatula transporter database: a comprehensive database resource for M. truncatula transporters

    Directory of Open Access Journals (Sweden)

    Miao Zhenyan

    2012-02-01

    Full Text Available Abstract Background Medicago truncatula has been chosen as a model species for genomic studies. It is closely related to an important legume, alfalfa. Transporters are a large group of membrane-spanning proteins. They deliver essential nutrients, eject waste products, and assist the cell in sensing environmental conditions by forming a complex system of pumps and channels. Although studies have effectively characterized individual M. truncatula transporters in several databases, until now there has been no available systematic database that includes all transporters in M. truncatula. Description The M. truncatula transporter database (MTDB contains comprehensive information on the transporters in M. truncatula. Based on the TransportTP method, we have presented a novel prediction pipeline. A total of 3,665 putative transporters have been annotated based on International Medicago Genome Annotated Group (IMGAG V3.5 V3 and the M. truncatula Gene Index (MTGI V10.0 releases and assigned to 162 families according to the transporter classification system. These families were further classified into seven types according to their transport mode and energy coupling mechanism. Extensive annotations referring to each protein were generated, including basic protein function, expressed sequence tag (EST mapping, genome locus, three-dimensional template prediction, transmembrane segment, and domain annotation. A chromosome distribution map and text-based Basic Local Alignment Search Tools were also created. In addition, we have provided a way to explore the expression of putative M. truncatula transporter genes under stress treatments. Conclusions In summary, the MTDB enables the exploration and comparative analysis of putative transporters in M. truncatula. A user-friendly web interface and regular updates make MTDB valuable to researchers in related fields. The MTDB is freely available now to all users at http://bioinformatics.cau.edu.cn/MtTransporter/.

  10. Evaluation of Effect of Silicon on NaCl Tolerance in Annual Medicago scutellata L.

    Directory of Open Access Journals (Sweden)

    M Azizi

    2016-07-01

    Full Text Available Introduction Salinity is one of the most important stress resulting depletion of vegetation in large areas of the world including some regions of Iran. Reduction of plant growth due to salinity occurs with a range of mechanisms, including low external water potential, ion toxicity and interfere with the uptake. Silicon (Si is the second most abundant element in soil and could efficiently mitigate the effects of various biotic and abiotic stresses, such as drought, heavy metal toxicity and salinity on plants. Medicago scutellata is an important leguminous forage crop throughout the world that could increase soil nitrogen content via reduction of atmospheric nitrogen. To our knowledge, no study have examined the interaction of salinity and Si nutrition in Medicago scutellata or how the beneficial effects of Si in salt-stressed M. scutellata plants (if any are exerted. Accordingly, the aim of the present study was to evaluate the effect of silicon nutrition on salt tolerance of Medicago scutellata. Materials and Methods Seeds of alfalfa (Medicago scutellata L. were sterilized with a 2.5% sodium hypochlorite solution and were incubated in a moistened paper towel. Then, they germinated in the dark at 255  C for 48 h. Healthy seedlings of uniform sizes were selected for hydroponic culture (Hoagland solution in a 10×15×15 cm plastic pots. A factorial experiment carried out based on a completely randomized design with two factors. The first factor was salinity, including 0 and 100 mM NaCl and the second was silicon nutrition, including 0, 0.75 and 1.5 m.M sodium silicate. The pH of the nutrient solution was adjusted daily at 6.4  0.2 and nutrient solution was refreshed weekly. During the experiment, maximum and minimum air temperatures were 30ºC and 21ºC respectively, and the mean relative humidity was 67%. Four weeks after exerting the treatments, plants were harvested and used for the assessment of growth parameters and chemical analyses

  11. Hybrid intermediaries

    OpenAIRE

    Cetorelli, Nicola

    2014-01-01

    I introduce the concept of hybrid intermediaries: financial conglomerates that control a multiplicity of entity types active in the "assembly line" process of modern financial intermediation, a system that has become known as shadow banking. The complex bank holding companies of today are the best example of hybrid intermediaries, but I argue that financial firms from the "nonbank" space can just as easily evolve into conglomerates with similar organizational structure, thus acquiring the cap...

  12. Hybrid composites

    CSIR Research Space (South Africa)

    Jacob John, Maya

    2009-04-01

    Full Text Available effect was observed for the elongation at break of the hybrid composites. The impact strength of the hybrid composites increased with the addition of glass fibres. The tensile and impact properties of thermoplastic natural rubber reinforced short... panels made from conventional structural materials. Figure 3 illustrates the performance of cellular biocomposite panels against conventional systems used for building and residential construction, namely a pre- cast pre-stressed hollow core concrete...

  13. Dyes Extracted from Safflower, Medicago Sativa, and Ros Marinus Oficinalis as Photosensitizers for Dye-sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Sofyan A. Taya

    2016-03-01

    Full Text Available In this work, three extracts of plant leaves were used as sensitizers for dye-sensitized solar cells (DSSCs. These plants are Safflower, Medicago sativa and Ros marinus oficinalis. The natural dyes were extracted before and after grinding the plant leaves. The UV-VIS absorption spectra of the three extracts in ethyl alcohol solution were measured. The DSSCs were assembled using TiO2 films on Fluorine-doped tin oxide (FTO coated glass. The DSSCs sensitized with the extracts of grinded leaves showed a better performance compared to those sensitized with un-grinded leaves with the highest efficiency of 0.115 % was obtained for the DSSC sensitized with Medicago sativa. The performance of the DSSCs sensitized with Safflower and Ros marinus oficinalis was significantly improved by acid treatment of the FTO substrates. Impedance spectroscopy of the fabricated cells was also carried out.

  14. Genome sequence of Ensifer medicae strain WSM1369; an effective microsymbiont of the annual legume Medicago sphaerocarpos.

    Science.gov (United States)

    Terpolilli, Jason; Garau, Giovanni; Hill, Yvette; Tian, Rui; Howieson, John; Bräu, Lambert; Goodwin, Lynne; Han, James; Liolios, Konstantinos; Huntemann, Marcel; Pati, Amrita; Woyke, Tanja; Mavromatis, Konstantinos; Markowitz, Victor; Ivanova, Natalia; Kyrpides, Nikos; Reeve, Wayne

    2013-12-20

    Ensifer medicae WSM1369 is an aerobic, motile, Gram-negative, non-spore-forming rod that can exist as a soil saprophyte or as a legume microsymbiont of Medicago. WSM1369 was isolated in 1993 from a nodule recovered from the roots of Medicago sphaerocarpos growing at San Pietro di Rudas, near Aggius in Sardinia (Italy). WSM1369 is an effective microsymbiont of the annual forage legumes M. polymorpha and M. sphaerocarpos. Here we describe the features of E. medicae WSM1369, together with genome sequence information and its annotation. The 6,402,557 bp standard draft genome is arranged into 307 scaffolds of 307 contigs containing 6,656 protein-coding genes and 79 RNA-only encoding genes. This rhizobial genome is one of 100 sequenced as part of the DOE Joint Genome Institute 2010 Genomic Encyclopedia for Bacteria and Archaea-Root Nodule Bacteria (GEBA-RNB) project.

  15. Nodule Initiation Involves the Creation of a New Symplasmic Field in Specific Root Cells of Medicago Species

    Science.gov (United States)

    Complainville, Arnaud; Brocard, Lysiane; Roberts, Ian; Dax, Edna; Sever, Noa; Sauer, Norbert; Kondorosi, Adam; Wolf, Shmuel; Oparka, Karl; Crespi, M.

    2003-01-01

    The organogenesis of nitrogen-fixing nodules in legume plants is initiated in specific root cortical cells and regulated by long-distance signaling and carbon allocation. Here, we explore cell-to-cell communication processes that occur during nodule initiation in Medicago species and their functional relevance using a combination of fluorescent tracers, electron microscopy, and transgenic plants. Nodule initiation induced symplasmic continuity between the phloem and nodule initials. Macromolecules such as green fluorescent protein could traffic across short or long distances from the phloem into these primordial cells. The created symplasmic field was regulated throughout nodule development. Furthermore, Medicago truncatula transgenic plants expressing a viral movement protein showed increased nodulation. Hence, the establishment of this symplasmic field may be a critical element for the control of nodule organogenesis. PMID:14615602

  16. A saturated genetic linkage map of autotetraploid alfalfa (Medicago sativa L.) developed using genotyping-by-sequencing is highly syntenous with the Medicago truncatula genome.

    Science.gov (United States)

    Li, Xuehui; Wei, Yanling; Acharya, Ananta; Jiang, Qingzhen; Kang, Junmei; Brummer, E Charles

    2014-08-21

    A genetic linkage map is a valuable tool for quantitative trait locus mapping, map-based gene cloning, comparative mapping, and whole-genome assembly. Alfalfa, one of the most important forage crops in the world, is autotetraploid, allogamous, and highly heterozygous, characteristics that have impeded the construction of a high-density linkage map using traditional genetic marker systems. Using genotyping-by-sequencing (GBS), we constructed low-cost, reasonably high-density linkage maps for both maternal and paternal parental genomes of an autotetraploid alfalfa F1 population. The resulting maps contain 3591 single-nucleotide polymorphism markers on 64 linkage groups across both parents, with an average density of one marker per 1.5 and 1.0 cM for the maternal and paternal haplotype maps, respectively. Chromosome assignments were made based on homology of markers to the M. truncatula genome. Four linkage groups representing the four haplotypes of each alfalfa chromosome were assigned to each of the eight Medicago chromosomes in both the maternal and paternal parents. The alfalfa linkage groups were highly syntenous with M. truncatula, and clearly identified the known translocation between Chromosomes 4 and 8. In addition, a small inversion on Chromosome 1 was identified between M. truncatula and M. sativa. GBS enabled us to develop a saturated linkage map for alfalfa that greatly improved genome coverage relative to previous maps and that will facilitate investigation of genome structure. GBS could be used in breeding populations to accelerate molecular breeding in alfalfa. Copyright © 2014 Li et al.

  17. THE EFFECT OF PRIMING ON GERMINATION AND SEEDLING GROWTH OF ALFALFA (MEDICAGO SATIVA L.) UNDER SALINITY STRESS

    OpenAIRE

    Jorjandi M.; SHARIFI SIRCHI G.R.

    2012-01-01

    Salinity stress is an abiotic stress which has harmful effects on germination, growth and yield of alfalfa (Medicago sativa L.) in many parts of the world. Seed priming is a way of increasing salt tolerance of plants. In this study, the effect of seed priming on germination and growth of alfalfa seedlings, Bami cultivar, under salinity condition was investigated. According to germination percentage of seeds under In vitro conditions, salicylic acid, Vitamin B12 and distilled water were select...

  18. Metabolite profiling of Triterpene Saponins in medicago truncatula hairy roots by liquid chromatography fourier transform Ion Cyclotron resonance mass spectrometry

    OpenAIRE

    Pollier, Jacob; Morreel, Kris; Geelen, Danny; Goossens, Alain

    2011-01-01

    Triterpenes are one of the largest classes of plant natural products, with an enormous variety in structure and bioactivities. Here, triterpene saponins from hairy roots of the model legume Medicago truncatula were profiled with reversed-phase liquid chromatography coupled to negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (LC ESI FT-ICR MS). Owing to the accuracy of the FT-ICR MS, reliable molecular formulas of the detected compounds could be ...

  19. Differential response of the plant Medicago truncatula to its symbiont Sinorhizobium meliloti or an exopolysaccharide-deficient mutant

    OpenAIRE

    Jones, Kathryn M.; Sharopova, Natalya; Lohar, Dasharath P.; Zhang, Jennifer Q.; Kathryn A VandenBosch; Walker, Graham C.

    2008-01-01

    Sinorhizobium meliloti forms symbiotic, nitrogen-fixing nodules on the roots of Medicago truncatula. The bacteria invade and colonize the roots through structures called infection threads. S. meliloti unable to produce the exopolysaccharide succinoglycan are unable to establish a symbiosis because they are defective in initiating the production of infection threads and in invading the plant. Here, we use microarrays representing 16,000 M. truncatula genes to compare the differential transcrip...

  20. Adaptive evolution of the symbiotic gene NORK is not correlated with shifts of rhizobial specificity in the genus Medicago

    Directory of Open Access Journals (Sweden)

    Ronfort Joëlle

    2007-11-01

    Full Text Available Abstract Background The NODULATION RECEPTOR KINASE (NORK gene encodes a Leucine-Rich Repeat (LRR-containing receptor-like protein and controls the infection by symbiotic rhizobia and endomycorrhizal fungi in Legumes. The occurrence of numerous amino acid changes driven by directional selection has been reported in this gene, using a limited number of messenger RNA sequences, but the functional reason of these changes remains obscure. The Medicago genus, where changes in rhizobial associations have been previously examined, is a good model to test whether the evolution of NORK is influenced by rhizobial interactions. Results We sequenced a region of 3610 nucleotides (encoding a 392 amino acid-long region of the NORK protein in 32 Medicago species. We confirm that positive selection in NORK has occurred within the Medicago genus and find that the amino acid positions targeted by selection occur in sites outside of solvent-exposed regions in LRRs, and other sites in the N-terminal region of the protein. We tested if branches of the Medicago phylogeny where changes of rhizobial symbionts occurred displayed accelerated rates of amino acid substitutions. Only one branch out of five tested, leading to M. noeana, displays such a pattern. Among other branches, the most likely for having undergone positive selection is not associated with documented shift of rhizobial specificity. Conclusion Adaptive changes in the sequence of the NORK receptor have involved the LRRs, but targeted different sites than in most previous studies of LRR proteins evolution. The fact that positive selection in NORK tends not to be associated to changes in rhizobial specificity indicates that this gene was probably not involved in evolving rhizobial preferences. Other explanations (e.g. coevolutionary arms race must be tested to explain the adaptive evolution of NORK.

  1. The impact of CdSe/ZnS Quantum Dots in cells of Medicago sativa in suspension culture

    Directory of Open Access Journals (Sweden)

    Maycock Christopher

    2010-10-01

    Full Text Available Abstract Background Nanotechnology has the potential to provide agriculture with new tools that may be used in the rapid detection and molecular treatment of diseases and enhancement of plant ability to absorb nutrients, among others. Data on nanoparticle toxicity in plants is largely heterogeneous with a diversity of physicochemical parameters reported, which difficult generalizations. Here a cell biology approach was used to evaluate the impact of Quantum Dots (QDs nanocrystals on plant cells, including their effect on cell growth, cell viability, oxidative stress and ROS accumulation, besides their cytomobility. Results A plant cell suspension culture of Medicago sativa was settled for the assessment of the impact of the addition of mercaptopropanoic acid coated CdSe/ZnS QDs. Cell growth was significantly reduced when 100 mM of mercaptopropanoic acid -QDs was added during the exponential growth phase, with less than 50% of the cells viable 72 hours after mercaptopropanoic acid -QDs addition. They were up taken by Medicago sativa cells and accumulated in the cytoplasm and nucleus as revealed by optical thin confocal imaging. As part of the cellular response to internalization, Medicago sativa cells were found to increase the production of Reactive Oxygen Species (ROS in a dose and time dependent manner. Using the fluorescent dye H2DCFDA it was observable that mercaptopropanoic acid-QDs concentrations between 5-180 nM led to a progressive and linear increase of ROS accumulation. Conclusions Our results showed that the extent of mercaptopropanoic acid coated CdSe/ZnS QDs cytotoxicity in plant cells is dependent upon a number of factors including QDs properties, dose and the environmental conditions of administration and that, for Medicago sativa cells, a safe range of 1-5 nM should not be exceeded for biological applications.

  2. Genome sequence of Ensifer medicae strain WSM1115; an acid-tolerant Medicago-nodulating microsymbiont from Samothraki, Greece.

    Science.gov (United States)

    Reeve, Wayne; Ballard, Ross; Howieson, John; Drew, Elizabeth; Tian, Rui; Bräu, Lambert; Munk, Christine; Davenport, Karen; Chain, Patrick; Goodwin, Lynne; Pagani, Ioanna; Huntemann, Marcel; Mavrommatis, Konstantinos; Pati, Amrita; Markowitz, Victor; Ivanova, Natalia; Woyke, Tanja; Kyrpides, Nikos

    2014-06-15

    Ensifer medicae strain WSM1115 forms effective nitrogen fixing symbioses with a range of annual Medicago species and is used in commercial inoculants in Australia. WSM1115 is an aerobic, motile, Gram-negative, non-spore-forming rod. It was isolated from a nodule recovered from the root of burr medic (Medicago polymorpha) collected on the Greek Island of Samothraki. WSM1115 has a broad host range for nodulation and N2 fixation capacity within the genus Medicago, although this does not extend to all medic species. WSM1115 is considered saprophytically competent in moderately acid soils (pH(CaCl2) 5.0), but it has failed to persist at field sites where soil salinity exceeded 10 ECe (dS/m). Here we describe the features of E. medicae strain WSM1115, together with genome sequence information and its annotation. The 6,861,065 bp high-quality-draft genome is arranged into 7 scaffolds of 28 contigs, contains 6,789 protein-coding genes and 83 RNA-only encoding genes, and is one of 100 rhizobial genomes sequenced as part of the DOE Joint Genome Institute 2010 Genomic Encyclopedia for Bacteria and Archaea-Root Nodule Bacteria (GEBA-RNB) project.

  3. An integrated genetic linkage map for white clover (Trifolium repens L.) with alignment to Medicago

    Science.gov (United States)

    2013-01-01

    Background White clover (Trifolium repens L.) is a temperate forage legume with an allotetraploid genome (2n=4×=32) estimated at 1093 Mb. Several linkage maps of various sizes, marker sources and completeness are available, however, no integrated map and marker set has explored consistency of linkage analysis among unrelated mapping populations. Such integrative analysis requires tools for homoeologue matching among populations. Development of these tools provides for a consistent framework map of the white clover genome, and facilitates in silico alignment with the model forage legume, Medicago truncatula. Results This is the first report of integration of independent linkage maps in white clover, and adds to the literature on methyl filtered GeneThresher®-derived microsatellite (simple sequence repeat; SSR) markers for linkage mapping. Gene-targeted SSR markers were discovered in a GeneThresher® (TrGT) methyl-filtered database of 364,539 sequences, which yielded 15,647 SSR arrays. Primers were designed for 4,038 arrays and of these, 465 TrGT-SSR markers were used for parental consensus genetic linkage analysis in an F1 mapping population (MP2). This was merged with an EST-SSR consensus genetic map of an independent population (MP1), using markers to match homoeologues and develop a multi-population integrated map of the white clover genome. This integrated map (IM) includes 1109 loci based on 804 SSRs over 1274 cM, covering 97% of the genome at a moderate density of one locus per 1.2 cM. Eighteen candidate genes and one morphological marker were also placed on the IM. Despite being derived from disparate populations and marker sources, the component maps and the derived IM had consistent representations of the white clover genome for marker order and genetic length. In silico analysis at an E-value threshold of 1e-20 revealed substantial co-linearity with the Medicago truncatula genome, and indicates a translocation between T. repens groups 2 and 6 relative to

  4. Lucern dehydration with blanching and pressing

    Energy Technology Data Exchange (ETDEWEB)

    Mathan, O. de

    1990-01-01

    The process is characterized by: - a high energetic performance - steam as unique thermal energy source - the improvement effect of cooking on organic matters digestibility, and on proteins degradation. First variant increases energetic performances by coupling the system with a total recycling small electrical pneumatic dryer. Second variant includes soluble foliar proteins rich juices extraction by the cooking parameters choices. 12 refs.; 3 figs.; 1 tab.

  5. supplemented with graded levels of lucerne

    African Journals Online (AJOL)

    In Kenya, dairy cattle under zero grazing system are mainly .... soluble fraction (0 h incubation, %) and kd is fractional rate of degradation (% h_1). ..... Influence of carbohydrate on feed intake, rumen fermentation and milk performance in.

  6. Morphological and Isozyme Variation in Natural Populations of the Genus Medicago L. Prospected in Northern Algeria

    Directory of Open Access Journals (Sweden)

    Imane MEDOUKALI

    2015-04-01

    Full Text Available As part of the evaluation and enhancement of genetic resources, morphological and isozyme variability within and among 169 accessions, representing 14 species of the genus Medicago L. collected in northern Algeria, was assessed using twelve quantitative traits and two enzymatic systems. Phenotype frequencies were scored in six enzyme zones to determine isozyme variability within and among populations. The data analysis resolved a high level of genetic diversity. Ten morphometric characteristics contributed to the discrimination of the species. The relationship between the collection site environment and phenotypic characteristics was also studied. Esterase (EST enzyme system was more polymorphic than glutamate oxaloacetate transaminase (GOT system. Were scored 2 zones with 10 bands and 21 phenotypes for GOT (glutamate oxaloacetate transaminase and 4 zones with 22 bands and 71 phenotypes for EST (esterase Polymorphism index and Jaccard’s genetic distances revealed the existence of a high genetic diversity within and among the studied populations. The annual species M. polymorpha presented an intraspecific polymorphism index of 0.57, which was higher than all other species indices. Clustering of the species based on isozyme markers was in agreement with taxonomic criteria and showed no significant correlation with morphological characteristics. Conservation programs should take into account the level of genetic diversity within and between populations revealed by isozyme markers.

  7. Characterization of green-tissue protein extract from alfalfa (Medicago sativa) exploiting a 3-D technique.

    Science.gov (United States)

    Aguilar, Oscar; Glatz, Charles E; Rito-Palomares, Marco

    2009-09-01

    There is a growing interest of pharmaceutical companies for plant-based production systems. To facilitate the general acceptance of plants as bioreactors, the establishment of efficient downstream operations is critical. It has been proposed that a better understanding of the properties of the contaminant proteins can benefit downstream processing design and operation. The coupled application of 2-DE with aqueous two-phase partitioning has been suggested as a practical 3-D method to characterize potential contaminant proteins from plant extracts. The application of this novel 3-D approach to a complex protein extract from alfalfa (Medicago sativa) containing a model recombinant protein (human granulocyte colony stimulating factor (hG-CSF)) resulted in the quantification of 55 protein spots. The 3-D properties (M(r), pI, and K(p)) obtained for 17 proteins comprising 69% of the alfalfa proteins, allowed the proposal of a prefractionation step as well as the identification of the target molecule (rG-CSF) from bulk of alfalfa proteins. The information obtained from this experimental approach was useful for the identification of the potential contaminant proteins that will occur in alfalfa when this plant is used as a host for recombinant proteins. Additionally, this method will assist in the design of adequate purification strategies for recombinant proteins expressed in alfalfa green tissue.

  8. Transcriptional and post-transcriptional regulation of a NAC1 transcription factor in Medicago truncatula roots.

    Science.gov (United States)

    D'haeseleer, Katrien; Den Herder, Griet; Laffont, Carole; Plet, Julie; Mortier, Virginie; Lelandais-Brière, Christine; De Bodt, Stefanie; De Keyser, Annick; Crespi, Martin; Holsters, Marcelle; Frugier, Florian; Goormachtig, Sofie

    2011-08-01

    • Legume roots develop two types of lateral organs, lateral roots and nodules. Nodules develop as a result of a symbiotic interaction with rhizobia and provide a niche for the bacteria to fix atmospheric nitrogen for the plant. • The Arabidopsis NAC1 transcription factor is involved in lateral root formation, and is regulated post-transcriptionally by miRNA164 and by SINAT5-dependent ubiquitination. We analyzed in Medicago truncatula the role of the closest NAC1 homolog in lateral root formation and in nodulation. • MtNAC1 shows a different expression pattern in response to auxin than its Arabidopsis homolog and no changes in lateral root number or nodulation were observed in plants affected in MtNAC1 expression. In addition, no interaction was found with SINA E3 ligases, suggesting that post-translational regulation of MtNAC1 does not occur in M. truncatula. Similar to what was found in Arabidopsis, a conserved miR164 target site was retrieved in MtNAC1, which reduced protein accumulation of a GFP-miR164 sensor. Furthermore, miR164 and MtNAC1 show an overlapping expression pattern in symbiotic nodules, and overexpression of this miRNA led to a reduction in nodule number. • This work suggests that regulatory pathways controlling a conserved transcription factor are complex and divergent between M. truncatula and Arabidopsis.

  9. Transcriptional responses of Medicago truncatula upon sulfur deficiency stress and arbuscular mycorrhizal symbios

    Directory of Open Access Journals (Sweden)

    Daniel eWipf

    2014-12-01

    Full Text Available Sulfur plays an essential role in plants’ growth and development and in their response to various abiotic and biotic stresses despite its leachability and its very low abundance in the only form that plant roots can uptake (sulfate. It is part of amino acids, glutathione (GSH, thiols of proteins and peptides, membrane sulfolipids, cell walls and secondary products, so reduced availability can drastically alter plant growth and development. The nutritional benefits of symbiotic interactions can help the plant in case of S deficiency. In particular the arbuscular mycorrhizal (AM interaction improves N, P and S plant nutrition, but the mechanisms behind these exchanges are not fully known yet. Although the transcriptional changes in the leguminous model plant Medicago truncatula have been already assessed in several biotic and/or abiotic conditions, S deficiency has not been considered so far. The aim of this work is to get a first overview on S-deficiency responses in the leaf and root tissues of plants interacting with the AM fungus Rhizophagus irregularis.Several hundred genes displayed significantly different transcript accumulation levels. Annotation and GO ID association were used to identify biological processes and molecular functions affected by sulfur starvation. Beside the beneficial effects of AM interaction, plants were greatly affected by the nutritional status, showing various differences in their transcriptomic footprints. Several pathways in which S plays an important role appeared to be differentially affected according to mycorrhizal status, with a generally reduced responsiveness to S deficiency in mycorrhized plants.

  10. [Responses of Medicago sativa and Astragalus adsurgens seedlings growth and water use to soil moisture regime].

    Science.gov (United States)

    Xu, Bingcheng; Shan, Lun; Li, Fengmin

    2005-12-01

    In the semi-arid area of Loess Plateau, seasonal drought often occurs during the vegetative stage of grass plants, leading to the subsequent serious reduction of their yield. Aimed to study the responses of the seedlings growth and water use of two perennial leguminous grasses Medicago sativa and Astragalus adsurgens to different soil moisture regimes, a pot experiment was installed with five treatments, i.e., adequate water supply (HW), moderate water stress (LW), soil drying gradually from HW (DHW) and LW (DLW), and refilling water to LW after soil drying from LW (RWL). The results showed that under HW, the seedlings of both M. sativa and A. adsurgens had the highest biomass and transpiration water use efficiency (TWUE), and M. sativa had a significantly higher biomass than A. adsurgens (P < 0.05). When the soil moisture content declined, M. sativa had a higher reduction rate in biomass and TWUE than A. adsurgens, and after the soil moisture regime changed from LW and DLW to RWL, the biomass of M. sativa and A. adsurgens was reduced by 47.8% and 27.9%, respectively, as compared to LW (P < 0.05). At the same time, the root/shoot ratio (R/S) of M. sativa and its water consumption per unit root increased significantly, while the TWUE decreased significantly (P < 0.05); but for A. adsurgens, its R/S decreased significantly (P < 0.05), while the TWUE and the water consumption per unit root had no significant change.

  11. Nodule and Leaf Nitrate Reductases and Nitrogen Fixation in Medicago sativa L. under Water Stress.

    Science.gov (United States)

    Aparicio-Tejo, P; Sánchez-Díaz, M

    1982-02-01

    The effect of water stress on patterns of nitrate reductase activity in the leaves and nodules and on nitrogen fixation were investigated in Medicago sativa L. plants watered 1 week before drought with or without NO(3) (-). Nitrogen fixation was decreased by water stress and also inhibited strongly by the presence of NO(3) (-). During drought, leaf nitrate reductase activity (NRA) decreased significantly particularly in plants watered with NO(3) (-), while with rewatering, leaf NRA recovery was quite important especially in the NO(3) (-)-watered plants. As water stress progressed, the nodular NRA increased both in plants watered with NO(3) (-) and in those without NO(3) (-) contrary to the behavior of the leaves. Beyond -15.10(5) pascal, nodular NRA began to decrease in plants watered with NO(3) (-). This phenomenon was not observed in nodules of plants given water only.Upon rewatering, it was observed that in plants watered with NO(3) (-) the nodular NRA increased again, while in plants watered but not given NO(3) (-), such activity began to decrease. Nitrogen fixation increased only in plants without NO(3) (-).

  12. Partitioning and mobilization of photoassimilate in alfalfa subjected to water deficits. [Medicago sativa L

    Energy Technology Data Exchange (ETDEWEB)

    Hall, M.H. (Univ. of Idaho, Moscow (USA)); Sheaffer, C.C.; Heichel, G.H. (Univ. of Minnesota, St. Paul (USA))

    Faster regrowth of a stressed alfalfa (Medicago sativa L.) crop compared to an unstressed crop after rewatering has been reported. The bases of this compensatory response are unknown, but they may be important to understanding adaptation to water stress and to developing crop water management strategies. The authors objectives was to determine the effect of stress induced by water deficit on photoassimilate partitioning and the utilization of stored assimilates during regrowth of alfalfa. Field and greenhouse experiments were conducted using cultivars differing in winterhardiness. Plants were subjected to water stress, pulse-labeled with {sup 14}CO{sub 2}, and sampled following 0, 1, 14, 21, and 28-d translocation periods. Following the 14-d sampling, herbage was harvested and water stress was removed. Cultivars contrasting in winterhardiness responded similarly to water stress. Stressed plant roots contained 73 and 114% more total plant radioactivity (TPR) than the control at the 1 and 14-d translocation periods, respectively. Water stress significantly increased root starch and TPR percentage in the starch fraction, but had much smaller effects on root soluble-sugar concentration and TPR percentage of the root sugar fraction. Herbage regrowth mass following harvest and rewatering of the water-stressed plants was similar to that of the control. Compared to the control, water-stressed alfalfa has greater total nonstructural carbohydrates in the roots, apparently due to increased photoassimilate partitioning to the roots. However, the greater root carbohydrate concentrations did not result in compensatory herbage regrowth following rewatering.

  13. Enhancement of lead uptake by alfalfa (Medicago sativa) using EDTA and a plant growth promoter.

    Science.gov (United States)

    López, Martha L; Peralta-Videa, Jose R; Benitez, Tenoch; Gardea-Torresdey, Jorge L

    2005-10-01

    Phytoremediation is a novel cleanup technology for the removal of contaminants from polluted waters and soils. In phytoremediation, the plant uptake capability and the availability of the pollutant in the media are important. Here we show the results of a study on the combined effects of ethylenediaminetetraacetic acid (EDTA) and the phytohormone indole-3-acetic acid (IAA) on Pb uptake by Medicago sativa (alfalfa). Plants were grown in hydroponics media containing a nutrient solution amended with Pb at 0.2mM and different combinations of EDTA, and IAA. After 10d of treatment, the Pb content in plant tissues was quantified using an Inductively Coupled Plasma Optical Emission Spectrometer (ICP/OES). The results showed that the combination of 100 microM IAA/0.2 mM EDTA increased the Pb accumulation in leaves by about 2800% and by about 600%, as compared to Pb content in leaves of plants exposed to Pb alone and those cultivated with Pb/EDTA, respectively. These results indicate that non-metal hyperaccumulator plants could increase their hyperaccumulating potential without genetic manipulation.

  14. Complete genome sequence of the Medicago microsymbiont Ensifer (Sinorhizobium) medicae strain WSM419

    Energy Technology Data Exchange (ETDEWEB)

    Reeve, Wayne [Murdoch University, Perth, Australia; Chain, Patrick S. G. [Lawrence Livermore National Laboratory (LLNL); O' Hara, Graham [Murdoch University, Perth, Australia; Ardley, Julie [Murdoch University, Perth, Australia; Nandesena, Kemanthi [Murdoch University, Perth, Australia; Brau, Lambert [Murdoch University, Perth, Australia; Tiwari, Ravi [Murdoch University, Perth, Australia; Malfatti, Stephanie [Lawrence Livermore National Laboratory (LLNL); Kiss, Hajnalka [Los Alamos National Laboratory (LANL); Lapidus, Alla L. [U.S. Department of Energy, Joint Genome Institute; Copeland, A [U.S. Department of Energy, Joint Genome Institute; Nolan, Matt [U.S. Department of Energy, Joint Genome Institute; Land, Miriam L [ORNL; Hauser, Loren John [ORNL; Chang, Yun-Juan [ORNL; Ivanova, N [U.S. Department of Energy, Joint Genome Institute; Mavromatis, K [U.S. Department of Energy, Joint Genome Institute; Markowitz, Victor [U.S. Department of Energy, Joint Genome Institute; Kyrpides, Nikos C [U.S. Department of Energy, Joint Genome Institute; Gollagher, Margaret [Murdoch University, Perth, Australia; Yates, Ron [Murdoch University, Perth, Australia; Dilworth, Michael [Murdoch University, Perth, Australia; Howieson, John [Murdoch University, Perth, Australia

    2010-01-01

    Ensifer (Sinorhizobium) medicae is an effective nitrogen fixing microsymbiont of a diverse range of annual Medicago (medic) species. Strain WSM419 is an aerobic, motile, non-spore forming, Gram-negative rod isolated from a M. murex root nodule collected in Sardinia, Italy in 1981. WSM419 was manufactured commercially in Australia as an inoculant for annual medics during 1985 to 1993 due to its nitrogen fixation, saprophytic competence and acid tolerance properties. Here we describe the basic features of this organism, together with the complete genome sequence, and annotation. This is the first report of a complete genome sequence for a microsymbiont of the group of annual medic species adapted to acid soils. We reveal that its genome size is 6,817,576 bp encoding 6,518 protein-coding genes and 81 RNA only encoding genes. The genome contains a chromosome of size 3,781,904 bp and 3 plasmids of size 1,570,951 bp, 1,245,408 bp and 219,313 bp. The smallest plasmid is a feature unique to this medic microsymbiont.

  15. Micromonospora from nitrogen fixing nodules of alfalfa (Medicago sativa L.). A new promising Plant Probiotic Bacteria.

    Science.gov (United States)

    Martínez-Hidalgo, Pilar; Galindo-Villardón, Purificación; Trujillo, Martha E; Igual, José M; Martínez-Molina, Eustoquio

    2014-09-17

    Biotic interactions can improve agricultural productivity without costly and environmentally challenging inputs. Micromonospora strains have recently been reported as natural endophytes of legume nodules but their significance for plant development and productivity has not yet been established. The aim of this study was to determine the diversity and function of Micromonospora isolated from Medicago sativa root nodules. Micromonospora-like strains from field alfalfa nodules were characterized by BOX-PCR fingerprinting and 16S rRNA gene sequencing. The ecological role of the interaction of the 15 selected representative Micromonospora strains was tested in M. sativa. Nodulation, plant growth and nutrition parameters were analyzed. Alfalfa nodules naturally contain abundant and highly diverse populations of Micromonospora, both at the intra- and at interspecific level. Selected Micromonospora isolates significantly increase the nodulation of alfalfa by Ensifer meliloti 1021 and also the efficiency of the plant for nitrogen nutrition. Moreover, they promote aerial growth, the shoot-to-root ratio, and raise the level of essential nutrients. Our results indicate that Micromonospora acts as a Rhizobia Helper Bacteria (RHB) agent and has probiotic effects, promoting plant growth and increasing nutrition efficiency. Its ecological role, biotechnological potential and advantages as a plant probiotic bacterium (PPB) are also discussed.

  16. Concerted changes in N and C primary metabolism in alfalfa (Medicago sativa) under water restriction.

    Science.gov (United States)

    Aranjuelo, Iker; Tcherkez, Guillaume; Molero, Gemma; Gilard, Françoise; Avice, Jean-Christophe; Nogués, Salvador

    2013-02-01

    Although the mechanisms of nodule N(2) fixation in legumes are now well documented, some uncertainty remains on the metabolic consequences of water deficit. In most cases, little consideration is given to other organs and, therefore, the coordinated changes in metabolism in leaves, roots, and nodules are not well known. Here, the effect of water restriction on exclusively N(2)-fixing alfalfa (Medicago sativa L.) plants was investigated, and proteomic, metabolomic, and physiological analyses were carried out. It is shown that the inhibition of nitrogenase activity caused by water restriction was accompanied by concerted alterations in metabolic pathways in nodules, leaves, and roots. The data suggest that nodule metabolism and metabolic exchange between plant organs nearly reached homeostasis in asparagine synthesis and partitioning, as well as the N demand from leaves. Typically, there was (i) a stimulation of the anaplerotic pathway to sustain the provision of C skeletons for amino acid (e.g. glutamate and proline) synthesis; (ii) re-allocation of glycolytic products to alanine and serine/glycine; and (iii) subtle changes in redox metabolites suggesting the implication of a slight oxidative stress. Furthermore, water restriction caused little change in both photosynthetic efficiency and respiratory cost of N(2) fixation by nodules. In other words, the results suggest that under water stress, nodule metabolism follows a compromise between physiological imperatives (N demand, oxidative stress) and the lower input to sustain catabolism.

  17. Selective lignin downregulation leads to constitutive defense response expression in alfalfa (Medicago sativa L.).

    Science.gov (United States)

    Gallego-Giraldo, Lina; Jikumaru, Yusuke; Kamiya, Yuji; Tang, Yuhong; Dixon, Richard A

    2011-05-01

    • Downregulation of hydroxycinnamoyl CoA: shikimate hydroxycinnamoyl transferase (HCT) in alfalfa (Medicago sativa) reduces lignin levels and improves forage quality and saccharification efficiency for bioethanol production. However, the plants have reduced stature. It was previously reported that HCT-down-regulated Arabidopsis have impaired auxin transport, but this has recently been disproved. • To address the basis for the phenotypes of lignin-modified alfalfa, we measured auxin transport, profiled a range of metabolites including flavonoids and hormones, and performed in depth transcriptome analyses. • Auxin transport is unaffected in HCT antisense alfalfa despite increased flavonoid biosynthesis. The plants show increased cytokinin and reduced auxin levels, and gibberellin levels and sensitivity are both reduced. Levels of salicylic, jasmonic and abscisic acids are elevated, associated with massive upregulation of pathogenesis and abiotic stress-related genes and enhanced tolerance to fungal infection and drought. • We suggest that HCT downregulated alfalfa plants exhibit constitutive activation of defense responses, triggered by release of bioactive cell wall fragments and production of hydrogen peroxide as a result of impaired secondary cell wall integrity. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.

  18. Screening of Cd tolerant genotypes and isolation of metallothionein genes in alfalfa (Medicago sativa L.).

    Science.gov (United States)

    Wang, Xiaojuan; Song, Yu; Ma, Yanhua; Zhuo, Renying; Jin, Liang

    2011-12-01

    In order to evaluate Cd tolerance in wide-ranging sources of alfalfa (Medicago sativa) and to identify Cd tolerant genotypes which may potentially be useful for restoring Cd-contaminated environments, thirty-six accessions of alfalfa were screened under hydroponic culture. Our results showed that the relative root growth rate varied from 0.48 to 1.0, which indicated that different alfalfa accessions had various responses to Cd stress. The candidate fragments derived from differentially expressed metallothionein (MT) genes were cloned from leaves of two Cd tolerant genotypes, YE and LZ. DNA sequence and the deduced protein sequence showed that MsMT2a and MsMT2b had high similarity to those in leguminous plants. DDRT-PCR analysis showed that MsMT2a expressed in both YE and LZ plants under control and Cd stress treatment, but MsMT2b only expressed under Cd stress treatment. This suggested that MsMT2a was universally expressed in leaves of alfalfa but expression of MsMT2b was Cadmium (Cd) inducible. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Accumulation and residue of napropamide in alfalfa (Medicago sativa) and soil involved in toxic response.

    Science.gov (United States)

    Cui, Li E; Yang, Hong

    2011-06-15

    Napropamide belongs to the amide herbicide family and widely used to control weeds in farmland. Intensive use of the herbicide has resulted in widespread contamination to ecosystems. The present study demonstrated an analysis on accumulation of the toxic pesticide napropamide in six genotypes of alfalfa (Medicago sativa), along with biological parameters and its residues in soils. Soil was treated with napropamide at 3 mg kg(-1) dry soil and alfalfa plants were cultured for 10 or 30 d, respectively. The maximum value for napropamide accumulation is 0.426 mg kg(-1) in shoots and 2.444 mg kg(-1) in roots. The napropamide-contaminated soil with alfalfa cultivation had much lower napropamide concentrations than the control (soil without alfalfa cultivation). Also, the content of napropamide residue in the rhizosphere was significantly lower than that in the non-rhizosphere soil. M. sativa exposed to 3 mg kg(-1) napropamide showed inhibited growth. Further analysis revealed that plants treated with napropamide accumulated more reactive oxygen species (O(2)(-) and H(2)O(2)) and less amounts of chlorophyll. However, not all cultivars showed oxidative injury, suggesting that the alfalfa cultivars display different tolerance to napropamide. Copyright © 2011 Elsevier B.V. All rights reserved.

  20. The thiol compounds glutathione and homoglutathione differentially affect cell development in alfalfa (Medicago sativa L.).

    Science.gov (United States)

    Pasternak, Taras; Asard, Han; Potters, Geert; Jansen, Marcel A K

    2014-01-01

    Glutathione (GSH) is an important scavenger of Reactive Oxygen Species (ROS), precursor of metal chelating phytochelatins, xenobiotic defence compound and regulator of cell proliferation. Homoglutathione (hGSH) is a GSH homologue that is present in several taxa in the family of Fabaceae. It is thought that hGSH performs many of the stress-defence roles typically ascribed to GSH, yet little is known about the potential involvement of hGSH in controlling cell proliferation. Here we show that hGSH/GSH ratios vary across organs and cells and that these changes in hGSH/GSH ratio occur during dedifferentiation and/or cell cycle activation events. The use of a GSH/hGSH biosynthesis inhibitor resulted in impaired cytokinesis in isolated protoplasts, showing the critical importance of these thiol-compounds for cell division. However, exposure of isolated protoplasts to exogenous GSH accelerated cytokinesis, while exogenous hGSH was found to inhibit the same process. We conclude that GSH and hGSH have distinct functional roles in cell cycle regulation in Medicago sativa L. GSH is associated with meristemic cells, and promotes cell cycle activation and induction of somatic embryogenesis, while hGSH is associated with differentiated cells and embryo proliferation. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  1. Stem nematode counteracts plant resistance of aphids in alfalfa, Medicago sativa.

    Science.gov (United States)

    Ramirez, Ricardo A; Spears, Lori R

    2014-10-01

    Plants are exploited by a diverse community of insect herbivores and phytopathogens that interact indirectly through plant-mediated interactions. Generally, plants are thought to respond to insects and pathogens through different defensive signaling pathways. As plants are selected for resistance to one phytophagous organism type (insect vs. pathogen) in managed systems, it is not clear how this selection may affect community interactions. This study examined the effect of nematode-resistant varieties on aphid (Acyrthosiphon pisum) suppression, and then determined how infection by the stem nematode, Ditylenchus dipsaci, mediated ecological effects on aphids and on plant defense proteins. Four alfalfa (Medicago sativa) varieties were selected with resistance to nematodes only (+,-), aphids only (-,+), nematodes and aphids (+,+), and susceptibility to nematodes and aphids (-,-). Field and greenhouse experiments were conducted to isolate the effect of nematode infection and aphid abundance on each variety. We found that varieties resistant to nematode, regardless of aphid resistance, had the lowest aphid counts, suggesting possible cross-resistance. Aphid abundance, however, increased when plants were exposed to nematodes. Resistant varieties were associated with elevated saponins but these compounds were not affected by insect or pathogen feeding. Concentrations of peroxidases and trypsin inhibitors, however, were increased in nematode resistant varieties when exposed to nematodes and aphids, respectively. The patterns of plant defense were variable, and a combination of resistance traits and changes in nutrient availability may drive positive interactions between nematodes and aphids aboveground.

  2. Enhanced salt tolerance of alfalfa (Medicago sativa) by rstB gene transformation.

    Science.gov (United States)

    Zhang, Wan-Jun; Wang, Tao

    2015-05-01

    Generating salt tolerance forage plant is essential for use of the land affected by high salinity. A salt tolerance gene rstB was used as a selectable marker gene in Agrobacterium-mediated transformation of tobacco under a selective regime of 170mM NaCl. The transgenic plants showed clear improvement in salt tolerance. To improve salt tolerance of alfalfa (Medicago sativa L.), rstB gene was introduced into alfalfa genome by Agrobacterium-mediated transformation. No abnormal phenotype was observed among the transgenic plants when compared with wild type (wt) plants. Significant enhancement of resistance to salt-shock treatment was noted on the rstB transgenic (T0) plants. Transgenic second-generation (T1) seeds showed improved germination rate and seedling growth under salt-stress condition. Hindered Na(+) accumulation, but enhanced Ca(2+) accumulation was observed on the rstB T1 plants when subjected to salt-stresses. Enhanced calcium accumulation in transgenic plants was also verified by cytohistochemical localization of calcium. Under salt-stress of 50mM NaCl, about 15% of the transgenic plants finished their life-cycle but the wt plants had no flower formation. The results demonstrated that the expression of rstB gene improved salt tolerance in transgenic alfalfa. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  3. Development of simple sequence repeat markers and diversity analysis in alfalfa (Medicago sativa L.).

    Science.gov (United States)

    Wang, Zan; Yan, Hongwei; Fu, Xinnian; Li, Xuehui; Gao, Hongwen

    2013-04-01

    Efficient and robust molecular markers are essential for molecular breeding in plant. Compared to dominant and bi-allelic markers, multiple alleles of simple sequence repeat (SSR) markers are particularly informative and superior in genetic linkage map and QTL mapping in autotetraploid species like alfalfa. The objective of this study was to enrich SSR markers directly from alfalfa expressed sequence tags (ESTs). A total of 12,371 alfalfa ESTs were retrieved from the National Center for Biotechnology Information. Total 774 SSR-containing ESTs were identified from 716 ESTs. On average, one SSR was found per 7.7 kb of EST sequences. Tri-nucleotide repeats (48.8 %) was the most abundant motif type, followed by di-(26.1 %), tetra-(11.5 %), penta-(9.7 %), and hexanucleotide (3.9 %). One hundred EST-SSR primer pairs were successfully designed and 29 exhibited polymorphism among 28 alfalfa accessions. The allele number per marker ranged from two to 21 with an average of 6.8. The PIC values ranged from 0.195 to 0.896 with an average of 0.608, indicating a high level of polymorphism of the EST-SSR markers. Based on the 29 EST-SSR markers, assessment of genetic diversity was conducted and found that Medicago sativa ssp. sativa was clearly different from the other subspecies. The high transferability of those EST-SSR markers was also found for relative species.

  4. Allelopathic interference of alfalfa (Medicago sativa L.) genotypes to annual ryegrass (Lolium rigidum).

    Science.gov (United States)

    Zubair, Hasan Muhammad; Pratley, James E; Sandral, G A; Humphries, A

    2017-07-01

    Alfalfa (Medicago sativa L.) genotypes at varying densities were investigated for allelopathic impact using annual ryegrass (Lolium rigidum) as the target species in a laboratory bioassay. Three densities (15, 30, and 50 seedlings/beaker) and 40 alfalfa genotypes were evaluated by the equal compartment agar method (ECAM). Alfalfa genotypes displayed a range of allelopathic interference in ryegrass seedlings, reducing root length from 5 to 65%. The growth of ryegrass decreased in response to increasing density of alfalfa seedlings. At the lowest density, Q75 and Titan9 were the least allelopathic genotypes. An overall inhibition index was calculated to rank each alfalfa genotype. Reduction in seed germination of annual ryegrass occurred in the presence of several alfalfa genotypes including Force 10, Haymaster7 and SARDI Five. A comprehensive metabolomic analysis using Quadruple Time of Flight (Q-TOF), was conducted to compare six alfalfa genotypes. Variation in chemical compounds was found between alfalfa root extracts and exudates and also between genotypes. Further individual compound assessments and quantitative study at greater chemical concentrations are needed to clarify the allelopathic activity. Considerable genetic variation exists among alfalfa genotypes for allelopathic activity creating the opportunity for its use in weed suppression through selection.

  5. Metabolomic Analysis of Alfalfa (Medicago sativa L.) Root-Symbiotic Rhizobia Responses under Alkali Stress.

    Science.gov (United States)

    Song, Tingting; Xu, Huihui; Sun, Na; Jiang, Liu; Tian, Pu; Yong, Yueyuan; Yang, Weiwei; Cai, Hua; Cui, Guowen

    2017-01-01

    Alkaline salts (e.g., NaHCO3 and Na2CO3) causes more severe morphological and physiological damage to plants than neutral salts (e.g., NaCl and Na2SO4) due to differences in pH. The mechanism by which plants respond to alkali stress is not fully understood, especially in plants having symbotic relationships such as alfalfa (Medicago sativa L.). Therefore, a study was designed to evaluate the metabolic response of the root-nodule symbiosis in alfalfa under alkali stress using comparative metabolomics. Rhizobium-nodulized (RI group) and non-nodulized (NI group) alfalfa roots were treated with 200 mmol/L NaHCO3 and, roots samples were analyzed for malondialdehydyde (MDA), proline, glutathione (GSH), superoxide dismutase (SOD), and peroxidase (POD) content. Additionally, metabolite profiling was conducted using gas chromatography combined with time-of-flight mass spectrometry (GC/TOF-MS). Phenotypically, the RI alfalfa exhibited a greater resistance to alkali stress than the NI plants examined. Physiological analysis and metabolic profiling revealed that RI plants accumulated more antioxidants (SOD, POD, GSH), osmolytes (sugar, glycols, proline), organic acids (succinic acid, fumaric acid, and alpha-ketoglutaric acid), and metabolites that are involved in nitrogen fixation. Our pairwise metabolomics comparisons revealed that RI alfalfa plants exhibited a distinct metabolic profile associated with alkali putative tolerance relative to NI alfalfa plants. Data provide new information about the relationship between non-nodulized, rhizobium-nodulized alfalfa and alkali resistance.

  6. [Determination of Hard Rate of Alfalfa (Medicago sativa L.) Seeds with Near Infrared Spectroscopy].

    Science.gov (United States)

    Wang, Xin-xun; Chen, Ling-ling; Zhang, Yun-wei; Mao, Pei-sheng

    2016-03-01

    Alfalfa (Medicago sativa L.) is the most commonly grown forage crop due to its better quality characteristics and high adaptability in China. However, there was 20%-80% hard seeds in alfalfa which could not be identified easily from non hard seeds which would cause the loss of seed utilization value and plant production. This experiment was designed for 121 samples of alfalfa. Seeds were collected according to different regions, harvested year and varieties. 31 samples were artificial matched as hard rates ranging from 20% to 80% to establish a model for hard seed rate by near infrared spectroscopy (NIRS) with Partial Least Square (PLS). The objective of this study was to establish a model and to estimate the efficiency of NIRS for determining hard rate of alfalfa seeds. The results showed that the correlation coefficient (R2(cal)) of calibration model was 0.981 6, root mean square error of cross validation (RMSECV) was 5.32, and the ratio of prediction to deviation (RPD) was 3.58. The forecast model in this experiment presented the satisfied precision. The proposed method using NIRS technology is feasible for identification and classification of hard seed in alfalfa. A new method, as nondestructive testing of hard seed rate, was provided to theoretical basis for fast nondestructive detection of hard seed rates in alfalfa.

  7. Ractopamine up take by alfalfa (Medicago sativa) and wheat (Triticum aestivum) from soil.

    Science.gov (United States)

    Shelver, Weilin L; DeSutter, Thomas M

    2015-08-01

    Ractopamine is a beta adrenergic agonist used as a growth promoter in swine, cattle and turkeys. To test whether ractopamine has the potential to accumulate in plants grown in contaminated soil, a greenhouse study was conducted with alfalfa (Medicago sativa) and wheat (Triticum aestivum) grown in two soils having different concentrations of organic matter (1.3% and 2.1%), amended with 0, 0.5, and 10 μg/g of ractopamine. Plant growth ranged from 2.7 to 8.8 g dry weight (dw) for alfalfa, and 8.7 to 40 g dw for wheat and was generally greater in the higher organic matter content soil. The uptake of ractopamine in plant tissues ranged from non-detectable to 897 ng/g and was strongly dependent on soil ractopamine concentration across soil and plant tissue. When adjusted to the total fortified quantities, the amount of ractopamine taken up by the plant tissue was low, <0.01% for either soil. Copyright © 2015. Published by Elsevier B.V.

  8. Nutraceutical Potential of New Alfalfa (Medicago sativa) Ingredients for Beverage Preparations.

    Science.gov (United States)

    Soto-Zarazúa, Maria Guadalupe; Bah, Moustapha; Costa, Anabela Silvia Gomes; Rodrigues, Francisca; Pimentel, Filipa Botelho; Rojas-Molina, Isela; Rojas, Alejandra; Pinto Oliveira, Maria Beatriz Prior

    2017-07-27

    Alfalfa (Medicago sativa) has been extensively used as animal feed, due to its fiber, protein, minerals, and vitamins, being also a useful source of phenolic compounds with potential therapeutic benefits. Nevertheless, its potential use as human ingredient is scarce. The aim of this work was to assess the nutritional composition, amino acid profile, and antioxidant capacity (AOC) of freeze-dried juice (FDJ) and fibrous residual material (RM), two new alfalfa-derived products (Adps) recently launched as ingredients for beverage preparations. Results demonstrated a high content of proteins (23-30 g/100 g FDJ and 13-17 g/100 g RM), crude fiber (29 g/100 g RM), and minerals (such as sodium, calcium, iron, and zinc). No significant difference was found in caloric content (4 kcal/g). Essential and nonessential amino acids were quantified in both Adps being leucine and lysine the most abundant. Total phenolic and total flavonoid contents (TPC and TFC, respectively) and their changes along the different harvesting periods of the year were also examined. FDJ presented the highest TPC in May (19 mg gallic acid equivalents/g dry weight [dw]), while in October TFC had the maximum value (4 mg catechin equivalents/g dw). Both products exhibited an interesting AOC by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and ferric reducing antioxidant power assays. This study reports the nutraceutical potential of two new types of Adps.

  9. MicroRNA156 improves drought stress tolerance in alfalfa (Medicago sativa) by silencing SPL13.

    Science.gov (United States)

    Arshad, Muhammad; Feyissa, Biruk A; Amyot, Lisa; Aung, Banyar; Hannoufa, Abdelali

    2017-05-01

    Alfalfa (Medicago sativa) is an important forage crop that is often grown in areas that frequently experience drought and water shortage. MicroRNA156 (miR156) is an emerging tool for improving various traits in plants. We tested the role of miR156d in drought response of alfalfa, and observed a significant improvement in drought tolerance of miR156 overexpression (miR156OE) alfalfa genotypes compared to the wild type control (WT). In addition to higher survival and reduced water loss, miR156OE genotypes also maintained higher stomatal conductance compared to WT during drought stress. Furthermore, we observed an enhanced accumulation of compatible solute (proline) and increased levels of abscisic acid (ABA) and antioxidants in miR156OE genotypes. Similarly, alfalfa plants with reduced expression of miR156-targeted SPL13 showed reduced water loss and enhanced stomatal conductance, chlorophyll content and photosynthetic assimilation. Several genes known to be involved in drought tolerance were differentially expressed in leaf and root of miR156 overexpression plants. Taken together, our findings reveal that miR156 improves drought tolerance in alfalfa at least partially by silencing SPL13. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  10. Medicago truncatula gene responses specific to arbuscular mycorrhiza interactions with different species and genera of Glomeromycota.

    Science.gov (United States)

    Massoumou, M; van Tuinen, D; Chatagnier, O; Arnould, C; Brechenmacher, L; Sanchez, L; Selim, S; Gianinazzi, S; Gianinazzi-Pearson, V

    2007-05-01

    Plant genes exhibiting common responses to different arbuscular mycorrhizal (AM) fungi and not induced under other biological conditions have been sought for to identify specific markers for monitoring the AM symbiosis. A subset of 14 candidate Medicago truncatula genes was identified as being potentially mycorrhiza responsive in previous cDNA microarray analyses and exclusive to cDNA libraries derived from mycorrhizal root tissues. Transcriptional activity of the selected plant genes was compared during root interactions with seven AM fungi belonging to different species of Glomus, Acaulospora, Gigaspora, or Scutellospora, and under widely different biological conditions (mycorrhiza, phosphate fertilization, pathogenic/beneficial microbe interactions, incompatible plant genotype). Ten of the M. truncatula genes were commonly induced by all the tested AM fungal species, and all were activated by at least two fungi. Most of the plant genes were transcribed uniquely in mycorrhizal roots, and several were already active at the appressorium stage of fungal development. Novel data provide evidence that common recognition responses to phylogenetically different Glomeromycota exist in plants during events that are unique to mycorrhiza interactions. They indicate that plants should possess a mycorrhiza-specific genetic program which is comodulated by a broad spectrum of AM fungi.

  11. Morphological and microsatellite diversity associated with ecological factors in natural populations of Medicago laciniata Mill. (Fabaceae)

    Indian Academy of Sciences (India)

    Mounawer Badri; Adel Zitoun; Houcine Ilahi; Thierry Huguet; Mohamed Elarbi Aouani

    2008-12-01

    Genetic variability in 10 natural Tunisian populations of Medicago laciniata were analysed using 19 quantitative traits and 12 polymorphic microsatellite loci. A large degree of genetic variability within-populations and among-populations was detected for both quantitative characters and molecular markers. High genetic differentiation among populations for quantitative traits was seen, with $Q_{ST} = 0.47$, and $F_{ST} = 0.47$ for microsatellite markers. Several quantitative traits displayed no statistical difference in the levels of $Q_{ST}$ and $F_{ST}$. Further, significant correlations between quantitative traits and eco-geographical factors suggest that divergence in the traits among populations may track environmental differences. There was no significant correlation between genetic variability at quantitative traits and microsatellite markers within populations. The site-of-origin of eco-geographical factors explain between 18.13% and 23.40% of genetic variance among populations at quantitative traits and microsatellite markers, respectively. The environmental factors that most influence variation in measured traits among populations are assimilated phosphorus (P205) and mean annual rainfall, followed by climate and soil texture, altitude and organic matter. Significant associations between eco-geographical factors and gene diversity, $H_{e}$, were established in five-microsatellite loci suggesting that these simple sequence repeats (SSRs) are not necessarily biologically neutral.

  12. Photosynthate partitioning and nitrogen fixation of alfalfa and birdsfoot trefoil. [Lotus corniculatus L. ; Medicago sativa L

    Energy Technology Data Exchange (ETDEWEB)

    Shieh, W.J.

    1985-01-01

    Nodule mass and number are usually correlated with rates of nitrogen fixation in legumes. Birdsfoot trefoil (Lotus corniculatus L.) with more than twice the nodule number and mass, however, fixes far less nitrogen than alfalfa (Medicago sativa L.) at the same age. In this research, photosynthesis and photosynthate partitioning and utilization in relation to nitrogen fixation of alfalfa and birdsfoot trefoil were examined in order to determine their relationship to nitrogen fixation potential. Photosynthate to nodules was studied using /sup 14/CO/sub 2/ labeling techniques. Partitioning patterns were altered by shading and dark depletion treatments. Efficiency of photosynthate utilization was examined by determining turnover of /sup 14/C photosynthate in nodule metabolites and by studying rates of cyanide-resistant and cyanide-sensitive O/sub 2/ uptake. Alfalfa nodule activity was greater than trefoil expressed on a hole pot or nodule dry weight basis. Both shading and dark treatments significantly reduced nodule activity as estimated by the acetylene reduction assay. Shoots of both species were found to be the dominant sinks for photosynthate. Percentage /sup 14/C recovered in alfalfa roots was more than twice that of trefoil at 1,2,3,4 and 24 h after labeling. Greater relative specific radioactivity (RSA) in nodules of both species suggests that they were stronger sinks for current photosynthate than roots.

  13. Hydrogen peroxide-regulated genes in the Medicago truncatula-Sinorhizobium meliloti symbiosis.

    Science.gov (United States)

    Andrio, Emilie; Marino, Daniel; Marmeys, Anthony; de Segonzac, Marion Dunoyer; Damiani, Isabelle; Genre, Andrea; Huguet, Stéphanie; Frendo, Pierre; Puppo, Alain; Pauly, Nicolas

    2013-04-01

    Reactive oxygen species (ROS), particularly hydrogen peroxide (H(2)O(2)), play an important role in signalling in various cellular processes. The involvement of H(2)O(2) in the Medicago truncatula-Sinorhizobium meliloti symbiotic interaction raises questions about its effect on gene expression. A transcriptome analysis was performed on inoculated roots of M. truncatula in which ROS production was inhibited with diphenylene iodonium (DPI). In total, 301 genes potentially regulated by ROS content were identified 2 d after inoculation. These genes included MtSpk1, which encodes a putative protein kinase and is induced by exogenous H(2)O(2) treatment. MtSpk1 gene expression was also induced by nodulation factor treatment. MtSpk1 transcription was observed in infected root hair cells, nodule primordia and the infection zone of mature nodules. Analysis with a fluorescent protein probe specific for H(2)O(2) showed that MtSpk1 expression and H(2)O(2) were similarly distributed in the nodule infection zone. Finally, the establishment of symbiosis was impaired by MtSpk1 downregulation with an artificial micro-RNA. Several genes regulated by H(2)O(2) during the establishment of rhizobial symbiosis were identified. The involvement of MtSpk1 in the establishment of the symbiosis is proposed. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  14. Histological and ultrastructure changes in Medicago sativa in response to lead stress

    Directory of Open Access Journals (Sweden)

    Fatemeh

    2013-07-01

    Full Text Available In the recent years, human activities such industry and agriculture promote heavy metal release into the environment. Lead is the most contaminant metals in environment which adversely affects both plant and human life. The present study was undertaken to determine the effects of Pb on structural characteristics in Medicago sativa L. 30 days plants treated with Pb in 5 treatments (0,120, 240, 500, 1000µM Pb with 3 repeat in per treatment for 10 days. Histochemical method of lead detection revealed significant accumulation of this metal in cortex and xylem tissues in roots and in stems lead deposits on cell wall of collenchymas tissues. The analysis of scanning electron micrographs of the leaf surface of M. sativa grown on hydroponic culture treated with Pb showed an increase in the size of guard cells in adaxial surface and decrease in abaxial surface, decrease in size of stomata aperture and closure of stomata in 1000 µM Pb in medium. Alternation of epicuticular waxes is one of the most important of pollution symptoms, in our study, alteration in structure and deposition of epicuticular waxes were observed. Also anatomical characteristics of stem and root affected by Pb contamination. Under Pb toxicity, anatomical symptoms including increase the diameter of stems and root as well as amplified vascular bundles and pith area were obsreved.

  15. Local replacement of ammophila arenaria by medicago marina after foredune trampling disturbance

    Directory of Open Access Journals (Sweden)

    Ana Ramos Pereira

    2013-06-01

    Full Text Available Human trampling is amongst the major causes of foredune disturbance. it creates a diffuse path network and the opening of bare‑ground clearings within dense vegetation patches as a result of plant removal, namely of Ammophila arenaria. in undisturbed plant communities A. arenaria becomes dominant, and strongly inhibits the co‑existence of other species, due to its phalanx growth strategy and by decreasing sand mobility near the surface. However, the dominance of this dune‑builder may be locally reversed after trampling disturbance. Data gathered in three foredune ‑sites at Vila nova de Gaia during 2006, three years after a major intervention by the Municipality to manage beach access through the dunes, suggest that a higher abundance of Medicago marina is linked to an increased availability of recruitment sites, due to death of A. arenaria individuals. acting as a powerful sand stabiliser, M. marina creates favourable conditions for annual species colonization of paths and gaps, significantly changing sand movement and deposition along the foredune gradient.

  16. Uptake of oxytetracycline and its phytotoxicity to alfalfa (Medicago sativa L.)

    Energy Technology Data Exchange (ETDEWEB)

    Kong, W.D. [Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Zhu, Y.G. [Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China)]. E-mail: ygzhu@rcees.ac.cn; Liang, Y.C. [Ministry of Agriculture Key Laboratory of Plant Nutrition and Nutrient Cycling, Institute of Soils and Fertilizers, Chinese Academy of Agricultural Sciences, Beijing 100081 (China); Zhang, J. [Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Smith, F.A. [Soil and Land Systems, School of Earth and Environmental Sciences, University of Adelaide, DP 636, Adelaide, SA 5005 (Australia); Yang, M. [Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China)

    2007-05-15

    A series of experiments were conducted in a hydroponic system to investigate the uptake of oxytetracycline (OTC) and its toxicity to alfalfa (Medicago sativa L.). OTC inhibited alfalfa shoot and root growth by up to 61% and 85%, respectively. The kinetics of OTC uptake could be well described by Michaelis-Menten equation with V {sub max} of 2.25 {mu}mol g{sup -1} fresh weight h{sup -1}, and K {sub m} of 0.036 mM. The uptake of OTC by alfalfa was strongly inhibited by the metabolic inhibitor, 2,4-DNP (2,4-dinitrophenol), at pH 3.5 and 6.0, but not by the aquaporin competitors, glycerol and Ag{sup +}. OTC uptake, however, was significantly inhibited by Hg{sup 2+}, suggesting that the inhibition of influx was due to general cellular stress rather than the specific action of Hg{sup 2+} on aquaporins. Results from the present study suggested that OTC uptake into alfalfa is an energy-dependent process. - Plant uptake of antibiotic oxytetracycline is energy-dependent.

  17. The Effects of Clinorotation on the Host Plant, Medicago truncatula, and Its Microbial Symbionts

    Directory of Open Access Journals (Sweden)

    Ariel J.C. Dauzart

    2016-02-01

    Full Text Available Understanding the outcome of the plant-microbe symbiosis in altered gravity is vital to developing life support systems for long-distance space travel and colonization of other planets. Thus, the aim of this research was to understand mutualistic relationships between plants and endophytic microbes under the influence of altered gravity. This project utilized the model tripartite relationship among Medicago truncatula ¬– Sinorhizobium meliloti – Rhizophagus irregularis. Plants were inoculated with rhizobial bacteria (S. meliloti, arbuscular mycorrhizal fungi (R. irregularis, or both microbes, and placed on a rotating clinostat. Vertical and horizontal static controls were also performed. Clinorotation significantly reduced M. truncatula dry mass and fresh mass compared to the static controls. The addition of rhizobia treatments under clinorotation also altered total root length and root-to-shoot fresh mass ratio. Nodule size decreased under rhizobia + clinorotation treatment, and nodule density was significantly decreased compared to the vertical treatment. However, inoculation with arbuscular mycorrhizal fungi was shown to increase biomass accumulation and nodule size. Thus, clinorotation significantly affected M. truncatula and its symbiotic relationships with S. meliloti and R. irregularis. In the long term, the results observed in this clinostat study on the changes of plant-microbe mutualism need to be investigated in spaceflight experiments. Thus, careful consideration of the symbiotic microbes of plants should be included in the design of bioregenerative life support systems needed for space travel.

  18. Genome-wide identification and expression analysis of auxin response factor gene family in Medicago truncatula

    Directory of Open Access Journals (Sweden)

    Chenjia eShen

    2015-02-01

    Full Text Available Auxin response factors (ARFs bind specifically to auxin response elements (AuxREs in the promoters of down-stream target genes and play roles in plant responses to diverse environmental factors. Using the latest updated Medicago truncatula reference genome sequence, a comprehensive characterization and analysis of 24 MtARF genes were performed. To uncover the basic information and functions of MtARF genes during symbiosis, we analyze the expression patterns of MtARF genes during the early phase of Sinorhizobium meliloti infection. The systematic analysis indicated that MtARF gene expressions were involved in the symbiosis processes. Furthermore, the roles of MtARF-mediated auxin signaling in symbiosis were tested in the infection resistant mutant (dmi3. The expression responses of MtARFs to S. meliloti infection were attenuated in the mutant compared to wild-type A17. In summary, our results shed that the MtARF gene expressions was involved in responses to S. meliloti infection, which may play an essential role in the regulation of nodule formation.

  19. Medicago sativa--Sinorhizobium meliloti Symbiosis Promotes the Bioaccumulation of Zinc in Nodulated Roots.

    Science.gov (United States)

    Zribi, Kais; Nouairi, Issam; Slama, Ines; Talbi-Zribi, Ons; Mhadhbi, Haythem

    2015-01-01

    In this study we investigated effects of Zn supply on germination, growth, inorganic solutes (Zn, Ca, Fe, and Mg) partitioning and nodulation of Medicago sativa This plant was cultivated with and without Zn (2 mM). Treatments were plants without (control) and with Zn tolerant strain (S532), Zn intolerant strain (S112) and 2 mM urea nitrogen fertilisation. Results showed that M. sativa germinates at rates of 50% at 2 mM Zn. For plants given nitrogen fertilisation, Zn increased plant biomass production. When grown with symbionts, Zn supply had no effect on nodulation. Moreover, plants with S112 showed a decrease of shoot and roots biomasses. However, in symbiosis with S532, an increase of roots biomass was observed. Plants in symbiosis with S. meliloti accumulated more Zn in their roots than nitrogen fertilised plants. Zn supply results in an increase of Ca concentration in roots of fertilised nitrogen plants. However, under Zn supply, Fe concentration decreased in roots and increased in nodules of plants with S112. Zn supply showed contrasting effects on Mg concentrations for plants with nitrogen fertilisation (increase) and plants with S112 (decrease). The capacity of M. sativa to accumulate Zn in their nodulated roots encouraged its use in phytostabilisation processes.

  20. Nodule carbohydrate catabolism is enhanced in the Medicago truncatula A17-Sinorhizobium medicae WSM419 symbiosis

    Directory of Open Access Journals (Sweden)

    Estibaliz eLarrainzar

    2014-08-01

    Full Text Available The symbiotic association between Medicago truncatula and Sinorhizobium meliloti is a well-established model system in the legume-Rhizobium community. Despite its wide use, the symbiotic efficiency of this model has been recently questioned and an alternative microsymbiont, S. medicae, has been proposed. However, little is known about the physiological mechanisms behind the higher symbiotic efficiency of S. medicae WSM419. In the present study, we inoculated M. truncatula Jemalong A17 with either S. medicae WSM419 or S. meliloti 2011 and compared plant growth, photosynthesis, N2-fixation rates, and plant nodule carbon and nitrogen metabolic activities in the two systems. M. truncatula plants in symbiosis with S. medicae showed increased biomass and photosynthesis rates per plant. Plants grown in symbiosis with S. medicae WSM419 also showed higher N2-fixation rates, which were correlated with a larger nodule biomass, while nodule number was similar in both systems. In terms of plant nodule metabolism, M. truncatula-S. medicae WSM419 nodules showed increased sucrose-catabolic activity, mostly associated with sucrose synthase, accompanied by a reduced starch content, whereas nitrogen-assimilation activities were comparable to those measured in nodules infected with S. meliloti 2011. Taken together, these results suggest that S. medicae WSM419 is able to enhance plant carbon catabolism in M. truncatula nodules, which allows for the maintaining of high symbiotic N2-fixation rates, better growth and improved general plant performance.

  1. [Influence of salt stress on the genetically polymorphic system of Sinorhizobium meliloti-Medicago truncatula].

    Science.gov (United States)

    Kurchak, O N; Provorov, N A; Onishchuk, O P; Vorobyov, N I; Roumiantseva, M L; Simarov, B V

    2014-07-01

    The impacts of salt stress (75 mM NaC1) on the ecological efficiency of the genetically polymorphic Sinorhizobium meliloti-Medicago truncatula system were studied. Its impact on a symbiotic system results in an increase of the partners' variability for symbiotic traits and of the symbiosis integrity as indicated by: a) the specificity of the partners' interactions--the nonadditive inputs of their genotypes into the variation of symbiotic parameters; and b) the correlative links between these parameters. The structure of the nodDI locus and the content correlates to the efficiency of the symbiosis between S. meliloti and M. truncatula genotypes under stress conditions more sufficiently than in the absence of stress. Correlations between the symbiotic efficiency of rhizobia strains and their growth rate outside symbiosis are expressed under stress conditions, not in the absence of stress. Under salt stress symbiotic effectiveness was decreased for M. truncatula line F83005.5, which was salt sensitive for mineral nutrition. The inhibition of symbiotic activity for this line is linked with decreased nodule formation, whereas for Jemalong 6 and DZA315.16 lines it is associated with repressed N2-fixation. It was demonstrated for the first time that salt stress impairs the M. truncatula habitus (the mass : height ratio increased 2- to 6-fold), which in the salt-resistant cultivar Jemalong 6 is normalized as the result of rhizobia inoculation.

  2. Molecular Signals Controlling the Inhibition of Nodulation by Nitrate in Medicago truncatula

    Directory of Open Access Journals (Sweden)

    Giel E. van Noorden

    2016-07-01

    Full Text Available The presence of nitrogen inhibits legume nodule formation, but the mechanism of this inhibition is poorly understood. We found that 2.5 mM nitrate and above significantly inhibited nodule initiation but not root hair curling in Medicago trunatula. We analyzed protein abundance in M. truncatula roots after treatment with either 0 or 2.5 mM nitrate in the presence or absence of its symbiont Sinorhizobium meliloti after 1, 2 and 5 days following inoculation. Two-dimensional gel electrophoresis combined with mass spectrometry was used to identify 106 differentially accumulated proteins responding to nitrate addition, inoculation or time point. While flavonoid-related proteins were less abundant in the presence of nitrate, addition of Nod gene-inducing flavonoids to the Sinorhizobium culture did not rescue nodulation. Accumulation of auxin in response to rhizobia, which is also controlled by flavonoids, still occurred in the presence of nitrate, but did not localize to a nodule initiation site. Several of the changes included defense- and redox-related proteins, and visualization of reactive oxygen species indicated that their induction in root hairs following Sinorhizobium inoculation was inhibited by nitrate. In summary, the presence of nitrate appears to inhibit nodulation via multiple pathways, including changes to flavonoid metabolism, defense responses and redox changes.

  3. Local and systemic proteomic changes in medicago truncatula at an early phase of Sinorhizobium meliloti infection.

    Science.gov (United States)

    Molesini, Barbara; Cecconi, Daniela; Pii, Youry; Pandolfini, Tiziana

    2014-02-07

    A symbiotic association with N-fixing bacteria facilitates the growth of leguminous plants under nitrogen-limiting conditions. The establishment of the symbiosis requires signal exchange between the host and the bacterium, which leads to the formation of root nodules, inside which bacteria are hosted. The formation of nodules is controlled through local and systemic mechanisms, which involves root-shoot communication. Our study was aimed at investigating the proteomic changes occurring in shoots and concomitantly in roots of Medicago truncatula at an early stage of Sinorhizobium meliloti infection. The principal systemic effects consisted in alteration of chloroplast proteins, induction of proteins responsive to biotic stress, and changes in proteins involved in hormonal signaling and metabolism. The most relevant local effect was the induction of proteins involved in the utilization of photosynthates and C-consuming processes (such as sucrose synthase and fructose-bisphosphate aldolase). In addition, some redox enzymes such as peroxiredoxin and ascorbate peroxidase showed an altered abundance. The analysis of local and systemic proteome changes suggests the occurrence of a stress response in the shoots and the precocious alteration of energy metabolism in roots and shoots. Furthermore, our data indicate the possibility that ABA and ethylene participate in the communicative network between root and shoot in the control of rhizobial infection.

  4. Overlap of proteome changes in Medicago truncatula in response to auxin and Sinorhizobium meliloti.

    Science.gov (United States)

    van Noorden, Giel E; Kerim, Tursun; Goffard, Nicolas; Wiblin, Robert; Pellerone, Flavia I; Rolfe, Barry G; Mathesius, Ulrike

    2007-06-01

    We used proteome analysis to identify proteins induced during nodule initiation and in response to auxin in Medicago truncatula. From previous experiments, which found a positive correlation between auxin levels and nodule numbers in the M. truncatula supernodulation mutant sunn (supernumerary nodules), we hypothesized (1) that auxin mediates protein changes during nodulation and (2) that auxin responses might differ between the wild type and the supernodulating sunn mutant during nodule initiation. Increased expression of the auxin response gene GH3:beta-glucuronidase was found during nodule initiation in M. truncatula, similar to treatment of roots with auxin. We then used difference gel electrophoresis and tandem mass spectrometry to compare proteomes of wild-type and sunn mutant roots after 24 h of treatment with Sinorhizobium meliloti, auxin, or a control. We identified 131 of 270 proteins responding to treatment with S. meliloti and/or auxin, and 39 of 89 proteins differentially displayed between the wild type and sunn. The majority of proteins changed similarly in response to auxin and S. meliloti after 24 h in both genotypes, supporting hypothesis 1. Proteins differentially accumulated between untreated wild-type and sunn roots also showed changes in auxin response, consistent with altered auxin levels in sunn. However, differences between the genotypes after S. meliloti inoculation were largely not due to differential auxin responses. The role of the identified candidate proteins in nodule initiation and the requirement for their induction by auxin could be tested in future functional studies.

  5. Medicago truncatula root nodule proteome analysis reveals differential plant and bacteroid responses to drought stress.

    Science.gov (United States)

    Larrainzar, Estíbaliz; Wienkoop, Stefanie; Weckwerth, Wolfram; Ladrera, Rubén; Arrese-Igor, Cesar; González, Esther M

    2007-07-01

    Drought is one of the environmental factors most affecting crop production. Under drought, symbiotic nitrogen fixation is one of the physiological processes to first show stress responses in nodulated legumes. This inhibition process involves a number of factors whose interactions are not yet understood. This work aims to further understand changes occurring in nodules under drought stress from a proteomic perspective. Drought was imposed on Medicago truncatula 'Jemalong A17' plants grown in symbiosis with Sinorhizobium meliloti strain 2011. Changes at the protein level were analyzed using a nongel approach based on liquid chromatography coupled to tandem mass spectrometry. Due to the complexity of nodule tissue, the separation of plant and bacteroid fractions in M. truncatula root nodules was first checked with the aim of minimizing cross contamination between the fractions. Second, the protein plant fraction of M. truncatula nodules was profiled, leading to the identification of 377 plant proteins, the largest description of the plant nodule proteome so far. Third, both symbiotic partners were independently analyzed for quantitative differences at the protein level during drought stress. Multivariate data mining allowed for the classification of proteins sets that were involved in drought stress responses. The isolation of the nodule plant and bacteroid protein fractions enabled the independent analysis of the response of both counterparts, gaining further understanding of how each symbiotic member is distinctly affected at the protein level under a water-deficit situation.

  6. Nitric oxide (NO): a key player in the senescence of Medicago truncatula root nodules.

    Science.gov (United States)

    Cam, Yvan; Pierre, Olivier; Boncompagni, Eric; Hérouart, Didier; Meilhoc, Eliane; Bruand, Claude

    2012-10-01

    Nitric oxide (NO) is a signalling and defence molecule involved in diverse plant developmental processes, as well as in the plant response to pathogens. NO has also been detected at different steps of the symbiosis between legumes and rhizobia. NO is required for an optimal establishment of the Medicago truncatula-Sinorhizobium meliloti symbiotic interaction, but little is known about the role of NO in mature nodules. Here, we investigate the role of NO in the late steps of symbiosis. Genetic and pharmacological approaches were conducted to modulate the NO level inside root nodules, and their effects on nitrogen fixation and root nodule senescence were monitored. An increase in endogenous NO levels led to a decrease in nitrogen fixation and early nodule senescence, characterized by cytological modifications of the nodule structure and the early expression of a specific senescence marker. By contrast, a decrease in NO levels led to a delay in nodule senescence. Together, our results strongly suggest that NO is a signal in developmental as well as stress-induced nodule senescence. In addition, this work demonstrates the pivotal role of the bacterial NO detoxification response in the prevention of early nodule senescence, and hence the maintenance of efficient symbiosis.

  7. Molecular cloning and characterization of a gene regulating flowering time from Alfalfa (Medicago sativa L.).

    Science.gov (United States)

    Zhang, Tiejun; Chao, Yuehui; Kang, Junmei; Ding, Wang; Yang, Qingchuan

    2013-07-01

    Genes that regulate flowering time play crucial roles in plant development and biomass formation. Based on the cDNA sequence of Medicago truncatula (accession no. AY690425), the LFY gene of alfalfa was cloned. Sequence similarity analysis revealed high homology with FLO/LFY family genes of other plants. When fused to the green fluorescent protein, MsLFY protein was localized in the nucleus of onion (Allium cepa L.) epidermal cells. The RT-qPCR analysis of MsLFY expression patterns showed that the expression of MsLFY gene was at a low level in roots, stems, leaves and pods, and the expression level in floral buds was the highest. The expression of MsLFY was induced by GA3 and long photoperiod. Plant expression vector was constructed and transformed into Arabidopsis by the agrobacterium-mediated methods. PCR amplification with the transgenic Arabidopsis genome DNA indicated that MsLFY gene had integrated in Arabidopsis genome. Overexpression of MsLFY specifically caused early flowering under long day conditions compared with non-transgenic plants. These results indicated MsLFY played roles in promoting flowering time.

  8. The arbuscular mycorrhizal symbiosis influences sulfur starvation responses of Medicago truncatula.

    Science.gov (United States)

    Sieh, Daniela; Watanabe, Mutsumi; Devers, Emanuel A; Brueckner, Franziska; Hoefgen, Rainer; Krajinski, Franziska

    2013-01-01

    Arbuscular mycorrhizal (AM) symbiosis is a mutualistic interaction that occurs between the large majority of vascular plants and fungi of the phylum Glomeromycota. In addition to other nutrients, sulfur compounds are symbiotically transferred from AM fungus to host plants; however, the physiological importance of mycorrhizal-mediated sulfur for plant metabolism has not yet been determined. We applied different sulfur and phosphate fertilization treatments to Medicago truncatula and investigated whether mycorrhizal colonization influences leaf metabolite composition and the expression of sulfur starvation-related genes. The expression pattern of sulfur starvation-related genes indicated reduced sulfur starvation responses in mycorrhizal plants grown at 1 mM phosphate nutrition. Leaf metabolite concentrations clearly showed that phosphate stress has a greater impact than sulfur stress on plant metabolism, with no demand for sulfur at strong phosphate starvation. However, when phosphate nutrition is high enough, mycorrhizal colonization reduces sulfur stress responses, probably as a result of symbiotic sulfur uptake. Mycorrhizal colonization is able to reduce sulfur starvation responses in M. truncatula when the plant's phosphate status is high enough that sulfur starvation is of physiological importance. This clearly shows the impact of mycorrhizal sulfur transfer on plant metabolism.

  9. Feasibility of annual alfalfa (Medicago scutellata cropping in Aq-Qalla township (Golestan province using GIS

    Directory of Open Access Journals (Sweden)

    niloofar Nasrollahi

    2015-12-01

    Full Text Available In this study, geographical information system (GIS and multi-criteria evaluation (MCE were applied to feasibility of agricultural lands in Aq-Qalla township for annual alfalfa (Medicago scutellata cultivation. For this purpose, required data and information of the study area collected during 2013, and thematic maps were provided. Kriging and IDW methods were applied to interpolation of environmental variables. The digital environmental layers overlaid and integrated in GIS media in respect to AHP weights and then zoning of lands carried out in four classes (high suitable, suitable, semi suitable and non-suitable. The results showed that 23.1% and 47/2% of this area were high suitable and suitable for alfalfa cropping, respectively. These zones had enough rainfall, suitable topography and high fertility. The semi- suitable and non- suitable regions (about 30% of area were located in the northwest, east and south of Aq-Qalla township. In these zones, the environmental requires of annual alfalfa had not fitted to ecological variables of agricultural land. In this study, the limitation factors were including: high EC (about 30 dS/m, deficient of organic matter, K and Ca In these zones, the environmental requires of annual alfalfa had not fitted to ecological variables of agricultural land. In this study, the limitation factors were including: high EC (about 30 dS/m, deficient of organic matter, K and Ca.

  10. Isolation, chemical characterization and biological activity of alfalfa (Medicago media Pers. root saponins

    Directory of Open Access Journals (Sweden)

    Wiesław Oleszek

    2014-01-01

    Full Text Available Saponins from alfalfa (Medicago media Pers. roots were isolated and their acid hydrolysis revealed several aglycones that were obtained in crystalline form and characterized. Medicagenic acid, hederagenin and soyasapogenols A. B, C. D, E and F were found. Crude saponins were separated into cholesterol-precipitable and nonprecipitable fractions. The precipitable fraction consisted of medicagenic acid glycosides: glucose, arabinose, xylose and rhamnose were found as their sugar chain components. The nonprecipitable fraction was a mixture of hederagenine and soyasapogenol glycosides, and glucose arthinose. xylose. galactose and glucuronic acid were found in the sugar component,. 7 he medicagenic acid glycosides made up 6% of root dry matter and showed high biological activity. They cuased red blood cells lysis (haemolytic index 3000, completely inhibited Trichoderma viride growth at the concentration of 2.5 Mg. 100 cm-3 of growth medium and retarded wheat seedling growth at concentrations as low as 100 ppm. The cholesterol-nonprecipitable fraction caused no blood cell lysis and fungus growth inhibition, although it did inhibit seedling growth, but to a much lesser extent than medicagenic acrd glycosides. The detrimental effect of alfalfa root saponins on winter wheat crop after alfalfa is discussed.

  11. The Effects of Clinorotation on the Host Plant, Medicago truncatula, and Its Microbial Symbionts

    Science.gov (United States)

    Dauzart, Ariel; Vandenbrink, Joshua; Kiss, John

    2016-02-01

    Understanding the outcome of the plant-microbe symbiosis in altered gravity is vital to developing life support systems for long-distance space travel and colonization of other planets. Thus, the aim of this research was to understand mutualistic relationships between plants and endophytic microbes under the influence of altered gravity. This project utilized the model tripartite relationship among Medicago truncatula ¬- Sinorhizobium meliloti - Rhizophagus irregularis. Plants were inoculated with rhizobial bacteria (S. meliloti), arbuscular mycorrhizal fungi (R. irregularis), or both microbes, and placed on a rotating clinostat. Vertical and horizontal static controls were also performed. Clinorotation significantly reduced M. truncatula dry mass and fresh mass compared to the static controls. The addition of rhizobia treatments under clinorotation also altered total root length and root-to-shoot fresh mass ratio. Nodule size decreased under rhizobia + clinorotation treatment, and nodule density was significantly decreased compared to the vertical treatment. However, inoculation with arbuscular mycorrhizal fungi was shown to increase biomass accumulation and nodule size. Thus, clinorotation significantly affected M. truncatula and its symbiotic relationships with S. meliloti and R. irregularis. In the long term, the results observed in this clinostat study on the changes of plant-microbe mutualism need to be investigated in spaceflight experiments. Thus, careful consideration of the symbiotic microbes of plants should be included in the design of bioregenerative life support systems needed for space travel.

  12. Toxic effects of arsenic on Sinorhizobium-Medicago sativa symbiotic interaction

    Energy Technology Data Exchange (ETDEWEB)

    Pajuelo, Eloisa [Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Seville, 41012 Seville (Spain); Rodriguez-Llorente, Ignacio D. [Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Seville, 41012 Seville (Spain)], E-mail: irodri@us.es; Dary, Mohammed; Palomares, Antonio J. [Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Seville, 41012 Seville (Spain)

    2008-07-15

    Recently, the Rhizobium-legume symbiotic interaction has been proposed as an interesting tool in bioremediation. However, little is known about the effect of most common contaminants on this process. The phytotoxic effects of arsenic on nodulation of Medicago sativa have been examined in vitro using the highly arsenic resistant and symbiotically effective Sinorhizobium sp. strain MA11. The bacteria were able to grow on plates containing As concentrations as high as 10 mM. Nevertheless, as little as 25-35 {mu}M arsenite produced a 75% decrease in the total number of nodules, due to a 90% reduction in the number of rhizobial infections, as could be determined using the strain MA11 carrying a lacZ reporter gene. This effect was associated to root hair damage and a shorter infective root zone. However, once nodulation was established nodule development seemed to continue normally, although earlier senescence could be observed in nodules of arsenic-grown plants. - First steps of nodulation of alfalfa, in particular infection thread formation, are more sensitive to As than nitrogen fixation due to plant effects.

  13. Mapping the genetic basis of symbiotic variation in legume-rhizobium interactions in Medicago truncatula.

    Science.gov (United States)

    Gorton, Amanda J; Heath, Katy D; Pilet-Nayel, Marie-Laure; Baranger, Alain; Stinchcombe, John R

    2012-11-01

    Mutualisms are known to be genetically variable, where the genotypes differ in the fitness benefits they gain from the interaction. To date, little is known about the loci that underlie such genetic variation in fitness or whether the loci influencing fitness are partner specific, and depend on the genotype of the interaction partner. In the legume-rhizobium mutualism, one set of potential candidate genes that may influence the fitness benefits of the symbiosis are the plant genes involved in the initiation of the signaling pathway between the two partners. Here we performed quantitative trait loci (QTL) mapping in Medicago truncatula in two different rhizobium strain treatments to locate regions of the genome influencing plant traits, assess whether such regions are dependent on the genotype of the rhizobial mutualist (QTL × rhizobium strain), and evaluate the contribution of sequence variation at known symbiosis signaling genes. Two of the symbiotic signaling genes, NFP and DMI3, colocalized with two QTL affecting average fruit weight and leaf number, suggesting that natural variation in nodulation genes may potentially influence plant fitness. In both rhizobium strain treatments, there were QTL that influenced multiple traits, indicative of either tight linkage between loci or pleiotropy, including one QTL with opposing effects on growth and reproduction. There was no evidence for QTL × rhizobium strain or genotype × genotype interactions, suggesting either that such interactions are due to small-effect loci or that more genotype-genotype combinations need to be tested in future mapping studies.

  14. The RPG gene of Medicago truncatula controls Rhizobium-directed polar growth during infection.

    Science.gov (United States)

    Arrighi, Jean-François; Godfroy, Olivier; de Billy, Françoise; Saurat, Olivier; Jauneau, Alain; Gough, Clare

    2008-07-15

    Rhizobia can infect roots of host legume plants and induce new organs called nodules, in which they fix atmospheric nitrogen. Infection generally starts with root hair curling, then proceeds inside newly formed, intracellular tubular structures called infection threads. A successful symbiotic interaction relies on infection threads advancing rapidly at their tips by polar growth through successive cell layers of the root toward developing nodule primordia. To identify a plant component that controls this tip growth process, we characterized a symbiotic mutant of Medicago truncatula, called rpg for rhizobium-directed polar growth. In this mutant, nitrogen-fixing nodules were rarely formed due to abnormally thick and slowly progressing infection threads. Root hair curling was also abnormal, indicating that the RPG gene fulfils an essential function in the process whereby rhizobia manage to dominate the process of induced tip growth for root hair infection. Map-based cloning of RPG revealed a member of a previously unknown plant-specific gene family encoding putative long coiled-coil proteins we have called RRPs (RPG-related proteins) and characterized by an "RRP domain" specific to this family. RPG expression was strongly associated with rhizobial infection, and the RPG protein showed a nuclear localization, indicating that this symbiotic gene constitutes an important component of symbiotic signaling.

  15. Glutamine synthetase in Medicago truncatula, unveiling new secrets of a very old enzyme

    Directory of Open Access Journals (Sweden)

    Ana Rita Seabra

    2015-07-01

    Full Text Available Glutamine Synthetase (GS catalyses the first step at which nitrogen is brought into cellular metabolism and is also involved in the reassimilation of ammonium released by a number of metabolic pathways. Due to its unique position in plant nitrogen metabolism, GS plays essential roles in all aspects of plant development, from germination to senescence, and is a key component of nitrogen use efficiency (NUE and plant yield. Understanding the mechanisms regulating GS activity is therefore of utmost importance and a great effort has been dedicated to understand how GS is regulated in different plant species. The present review summarizes exciting recent developments concerning the structure and regulation of glutamine synthetase isoenzymes, using the model legume Medicago truncatula. These include the understanding of the structural determinants of both the cytosolic and plastid located isoenzymes, the existence of a seed-specific GS gene unique to M. truncatula and closely related species and the discovery that GS isoenzymes are regulated by nitric oxide at the post-translational level. The data is discussed and integrated with the potential roles of the distinct GS isoenzymes within the whole plant context.

  16. Glutamine synthetase in Medicago truncatula, unveiling new secrets of a very old enzyme.

    Science.gov (United States)

    Seabra, Ana R; Carvalho, Helena G

    2015-01-01

    Glutamine synthetase (GS) catalyzes the first step at which nitrogen is brought into cellular metabolism and is also involved in the reassimilation of ammonium released by a number of metabolic pathways. Due to its unique position in plant nitrogen metabolism, GS plays essential roles in all aspects of plant development, from germination to senescence, and is a key component of nitrogen use efficiency (NUE) and plant yield. Understanding the mechanisms regulating GS activity is therefore of utmost importance and a great effort has been dedicated to understand how GS is regulated in different plant species. The present review summarizes exciting recent developments concerning the structure and regulation of GS isoenzymes, using the model legume Medicago truncatula. These include the understanding of the structural determinants of both the cytosolic and plastid located isoenzymes, the existence of a seed-specific GS gene unique to M. truncatula and closely related species and the discovery that GS isoenzymes are regulated by nitric oxide at the post-translational level. The data is discussed and integrated with the potential roles of the distinct GS isoenzymes within the whole plant context.

  17. From embryo sac to oil and protein bodies: embryo development in the model legume Medicago truncatula.

    Science.gov (United States)

    Wang, Xin-Ding; Song, Youhong; Sheahan, Michael B; Garg, Manohar L; Rose, Ray J

    2012-01-01

    • The cell and developmental biology of zygotic embryogenesis in the model legume Medicago truncatula has received little attention. We studied M. truncatula embryogenesis from embryo sac until cotyledon maturation, including oil and protein body biogenesis. • We characterized embryo development using light and electron microscopy, measurement of protein and lipid fatty acid accumulation and by profiling the expression of key seed storage genes. • Embryo sac development in M. truncatula is of the Polygonum type. A distinctive multicellular hypophysis and suspensor develops before the globular stage and by the early cotyledon stage, the procambium connects the developing apical meristems. In the storage parenchyma of cotyledons, ovoid oil bodies surround protein bodies and the plasma membrane. Four major lipid fatty acids accumulate as cotyledons develop, paralleling the expression of OLEOSIN and the storage protein genes, VICILIN and LEGUMIN. • Zygotic embryogenesis in M. truncatula features the development of a distinctive multicellular hypophysis and an endopolyploid suspensor with basal transfer cell. A clear procambial connection between the apical meristems is evident and there is a characteristic arrangement of oil bodies in the cotyledons and radicle. Our data help link embryogenesis to the genetic regulation of oil and protein body biogenesis in legume seed.

  18. Comparative Transcriptomic Analysis of Salt Adaptation in Roots of Contrasting Medicago truncatula Genotypes

    Institute of Scientific and Technical Information of China (English)

    Ons Zahaf; Anouck Diet; Mounawer Badri; Ana Zabalza; Esther M.González; Hervé Delacroix; Véronique Gruber; Florian Frugier; Martin Crespi; Sandrine Blanchet; Axel de Zélicourt; Beno(i)t Alunni; Julie Plet; Carole Laffont; Laura de Lorenzo; Sandrine Imbeaud; Jean-Laurent Ichanté

    2012-01-01

    Evolutionary diversity can be driven by the interaction of plants with different environments.Molecular bases involved in ecological adaptations to abiotic constraints can be explored using genomic tools.Legumes are major crops worldwide and soil salinity is a main stress affecting yield in these plants.We analyzed in the Medicago truncatula legume the root transcriptome of two genotypes having contrasting responses to salt stress:TN1.11,sampled in a salty Tunisian soil,and the reference Jemalong A17 genotype.TN1.11 plants show increased root growth under salt stress as well as a differential accumulation of sodium ions when compared to A17.Transcriptomic analysis revealed specific gene clusters preferentially regulated by salt in root apices of TN1.11,notably those related to the auxin pathway and to changes in histone variant isoforms.Many genes encoding transcription factors (TFs) were also differentially regulated between the two genotypes in response to salt.Among those selected for functional studies,overexpression in roots of the A17 genotype of the bHLH-type TF most differentially regulated between genotypes improved significantly root growth under salt stress.Despite the global complexity of the differential transcriptional responses,we propose that an increase in this bHLH TF expression may be linked to the adaptation of M.truncatula to saline soil environments.

  19. A Medicago truncatula mutant hyper-responsive to mycorrhiza and defective for nodulation.

    Science.gov (United States)

    Morandi, Dominique; le Signor, Christine; Gianinazzi-Pearson, Vivienne; Duc, Gérard

    2009-08-01

    One key strategy for the identification of plant genes required for mycorrhizal development is the use of plant mutants affected in mycorrhizal colonisation. In this paper, we report a new Medicago truncatula mutant defective for nodulation but hypermycorrhizal for symbiosis development and response. This mutant, called B9, presents a poor shoot and, especially, root development with short laterals. Inoculation with Glomus intraradices results in significantly higher root colonisation of the mutant than the wild-type genotype A17 (+20% for total root length, +16% for arbuscule frequency in the colonised part of the root, +39% for arbuscule frequency in the total root system). Mycorrhizal effects on shoot and root biomass of B9 plants are about twofold greater than in the wild-type genotype. The B9 mutant of M. truncatula is characterised by considerably higher root concentrations of the phytoestrogen coumestrol and by the novel synthesis of the coumestrol conjugate malonyl glycoside, absent from roots of wild-type plants. In conclusion, this is the first time that a hypermycorrhizal plant mutant affected negatively for nodulation (Myc(++), Nod (-/+) phenotype) is reported. This mutant represents a new tool for the study of plant genes differentially regulating mycorrhiza and nodulation symbioses, in particular, those related to autoregulation mechanisms.

  20. SRAP polymorphisms associated with superior freezing tolerance in alfalfa (Medicago sativa spp. sativa).

    Science.gov (United States)

    Castonguay, Yves; Cloutier, Jean; Bertrand, Annick; Michaud, Réal; Laberge, Serge

    2010-05-01

    Sequence-related amplified polymorphism (SRAP) analysis was used to uncover genetic polymorphisms among alfalfa populations recurrently selected for superior tolerance to freezing (TF populations). Bulk DNA samples (45 plants/bulk) from each of the cultivar Apica (ATF0), and populations ATF2, ATF4, ATF5, and ATF6 were evaluated with 42 different SRAP primer pairs. Several polymorphisms that progressively intensified or decreased with the number of recurrent cycles were identified. Four positive polymorphisms (F10-R14, Me4-R8, F10-R8 and F11-R9) that, respectively, yielded 540-, 359-, 213-, and 180-bp fragments were selected for further analysis. SRAP amplifications with genotypes within ATF populations confirmed that the polymorphisms identified with bulk DNA samples were reflecting changes in the frequency of their occurrence in response to selection. In addition, the number of genotypes cumulating multiple polymorphisms markedly increased in response to recurrent selection. Independent segregation of the four SRAP polymorphisms suggests location at unlinked loci. Homology search gave matches with BAC clones from syntenic Medicago truncatula for the four SRAP fragments. Analysis of the relationship with low temperature tolerance showed that multiple SRAP polymorphisms are more frequent in genotypes that maintain superior regrowth after freezing. These results show that SRAP analysis of bulk DNA samples from recurrent selections is an effective approach for the identification of genetic polymorphisms associated with quantitative traits in allogamous species. These polymorphisms could be useful tools for indirect selection of freezing tolerance in alfalfa.

  1. Mixed Nodule Infection in Sinorhizobium meliloti-Medicago sativa Symbiosis Suggest the Presence of Cheating Behavior.

    Science.gov (United States)

    Checcucci, Alice; Azzarello, Elisa; Bazzicalupo, Marco; Galardini, Marco; Lagomarsino, Alessandra; Mancuso, Stefano; Marti, Lucia; Marzano, Maria C; Mocali, Stefano; Squartini, Andrea; Zanardo, Marina; Mengoni, Alessio

    2016-01-01

    In the symbiosis between rhizobia and legumes, host plants can form symbiotic root nodules with multiple rhizobial strains, potentially showing different symbiotic performances in nitrogen fixation. Here, we investigated the presence of mixed nodules, containing rhizobia with different degrees of mutualisms, and evaluate their relative fitness in the Sinorhizobium meliloti-Medicago sativa model symbiosis. We used three S. meliloti strains, the mutualist strains Rm1021 and BL225C and the non-mutualist AK83. We performed competition experiments involving both in vitro and in vivo symbiotic assays with M. sativa host plants. We show the occurrence of a high number (from 27 to 100%) of mixed nodules with no negative effect on both nitrogen fixation and plant growth. The estimation of the relative fitness as non-mutualist/mutualist ratios in single nodules shows that in some nodules the non-mutualist strain efficiently colonized root nodules along with the mutualist ones. In conclusion, we can support the hypothesis that in S. meliloti-M. sativa symbiosis mixed nodules are formed and allow non-mutualist or less-mutualist bacterial partners to be less or not sanctioned by the host plant, hence allowing a potential form of cheating behavior to be present in the nitrogen fixing symbiosis.

  2. Germination of Medicago sativa is inhibited by soluble compounds in cement dust.

    Science.gov (United States)

    Lafragüeta, Cristina; García-Criado, Balbino; Arranz, Angel; Vázquez-de-Aldana, Beatriz R

    2014-01-01

    Deposition of cement dust on soils and plant surfaces is known to affect plant growth and the species composition of plant communities, but little is known about its effects (and those of its pH and constituents) on germination. Therefore, the aim of this study was to assess the toxicity of an aqueous cement extract, constituents of the extract and pH on the germination of seeds of a selected species, Medicago sativa. First, the effects of the extract were tested in assays with concentrations and exposure durations ranging from 0 to 1.0 g/mL and 4 to 96 h, respectively. At 0.8 g/mL, the extract strongly inhibited germination; a 4-h exposure reduced the germination rate, from 77 ± 1.8 to 50 ± 2.6% (mean ± SE), while 8-h exposure completely inhibited it. Further, treatment at this concentration killed the non-germinating seeds, thus the inhibition was due to toxic effects. Neither the pH of the extract nor the concentration of its main soluble elements separately (K, Ca, S, Na, or Cr) caused the toxicity since germination rates were not significantly reduced when these variables were tested individually. However, a mixture of the elements in solution reduced germination rates, suggesting that they have adverse synergistic effects.

  3. Spectinomycin resistance mutations in the rrn16 gene are new plastid markers in Medicago sativa.

    Science.gov (United States)

    Dudas, Brigitta; Jenes, Barnabas; Kiss, Gyorgy Botond; Maliga, Pal

    2012-11-01

    We report here the isolation of spectinomycin-resistant mutants in cultured cells of Medicago sativa line RegenSY-T2. Spectinomycin induces bleaching of cultured alfalfa cells due to inhibition of protein synthesis on the prokaryotic type 70S plastid ribosomes. Spontaneous mutants resistant to spectinomycin bleaching were identified by their ability to form green shoots on plant regeneration medium containing selective spectinomycin concentrations in the range of 25-50 mg/l. Sequencing of the plastid rrn16 gene revealed that spectinomycin resistance is due to mutations in a conserved stem structure of the 16S rRNA. Resistant plants transferred to the greenhouse developed normally and produced spectinomycin-resistant seed progeny. In light of their absence in soybean, a related leguminous plant, the isolation of spectinomycin-resistant mutants in M. sativa was unexpected. The new mutations are useful for the study of plastid inheritance, as demonstrated by detection of predominantly paternal plastid inheritance in the RegenSY-T2 × Szapko57 cross, and can be used as selective markers in plastid transformation vectors to obtain cisgenic plants.

  4. Evaluation of Medicago sativa L. sprouts as antihyperlipidemic and antihyperglycemic agent.

    Science.gov (United States)

    Seida, Ahmed; El-Hefnawy, Hala; Abou-Hussein, Dina; Mokhtar, Fatma Alzahraa; Abdel-Naim, Ashraf

    2015-11-01

    Medicago sativa L. (Alfalfa) is traditionally used to treat diabetes. This study was designed to investigate the potential antihyperlipidemic and antihyperglycemic activity of M. sativa sprouts in streptozotocin (STZ) induced diabetes via i.p. injection of 55 mg/kg of STZ. Experimental animals were divided into the following groups: GP1 (normal), GP2 (STZ-hyperlipidemic), GP3 (rouvastatin), GP4 (metformin), GP 5-9 (diabetic treated with methanolic, petroleum ether, chloroform, ethyl acetate and butanol extracts). The administration of the total methanolic extract (500 mg/kg), the petroleum ether (32.5mg) and butanol fractions (60 mg) for 4 weeks significantly decreased (p<0.05) triglycerides (TG), total cholesterol (TC), low-density lipoproteins (LDL) and very low density lipoproteins (VLDL) in comparison to rouvastatin. Petroleum ether fraction proved to exhibit the best activity as antihyperlipidemic agent (12.23%). On the other hand, ethyl acetate fraction retained the best activity (vs. metformin) as antihyperglycemic agent. Histopathological evidences on liver, pancreas and spleen were in agreement with the above mentioned results. Purification, characterization, and identification of isolated compounds from the active fractions afforded 9 compounds: β-sitosterol and stigmasterol from the petroleum ether fraction; 10-hydroxy-coumestrol, apigenin, genistein, p-hydroxy-benzoic-acid, 7, 4'- dihydroxyflavone, quercetin-3-glucoside and sissotrin from the ethyl acetate fraction.

  5. Allelopatic effects of cyanobacteria extracts containing microcystins on Medicago sativa-Rhizobia symbiosis.

    Science.gov (United States)

    El Khalloufi, Fatima; Oufdou, Khalid; Lahrouni, Majida; El Ghazali, Issam; Saqrane, Sanaa; Vasconcelos, Vitor; Oudra, Brahim

    2011-03-01

    The eutrophication of water leads to massive blooms of cyanobacteria potentially producers of highly toxic substances: cyanotoxins, especially microcystins (MC). The contamination of water used for irrigation by these toxins, can cause several adverse effects on plants and microorganisms. In this work, we report the phytotoxic effects of microcystins on the development of symbiosis between the leguminous plant Medicago sativa (Alfalfa) and rhizobia strains. The exposure of rhizobial strains to three different concentrations 0.01, 0.05 and 0.1 μg MC ml(-1) led to decrease on the bacteria growth. The strains of rhizobia Rh L1, Rh L2, Rh L3 and Rh L4 reduced their growth to, respectively, 20.85%, 20.80%, 33.19% and 25.65%. The chronic exposure of alfalfa seeds and seedlings to different MC concentrations affects the whole stages of plant development. The germination process has also been disrupted with an inhibition, which reaches 68.34% for a 22.24 μg MC ml(-1). Further, seedlings growth and photosynthetic process were also disrupted. The toxins reduced significantly the roots length and nodule formation and leads to an oxidative stress. Thus, the MCs contained in lake water and used for irrigation affect the development of symbiosis between M. sativa and Rhizobia.

  6. Microbiote shift in the Medicago sativa rhizosphere in response to cyanotoxins extract exposure.

    Science.gov (United States)

    El Khalloufi, Fatima; Oufdou, Khalid; Bertrand, Marie; Lahrouni, Majida; Oudra, Brahim; Ortet, Philippe; Barakat, Mohamed; Heulin, Thierry; Achouak, Wafa

    2016-01-01

    The bloom-containing water bodies may have an impact due to cyanotoxins production on other microorganisms and aquatic plants. Where such water is being used for crops irrigation, the presence of cyanotoxins may also have a toxic impact on terrestrial plants and their rhizosphere microbiota. For that purpose, PCR-based 454 pyrosequencing was applied to phylogenetically characterize the bacterial community of Medicago sativa rhizosphere in response to cyanotoxins extract. This analysis revealed a wide diversity at species level, which decreased from unplanted soil to root tissues indicating that only some populations were able to compete for nutrients and niches in this selective habitat. Gemmatimonas, Actinobacteria, Deltaproteobacteria and Opitutae mainly inhabited the bulk soil, whereas, the root-adhering soil and the root tissues were inhabited by Gammaproteobacteria and Alphaproteobacteria. The proportion of these populations fluctuated in response to cyanotoxins extract exposure. Betaproteobacteria proportion increased in the three studied compartments, whereas Gammaproteobacteria proportion decreased except in the bulk soil. This study revealed the potential toxicity of cyanotoxins extract towards Actinobacteria, Gemmatimonas, Deltaproteobacteria, and Gammaproteobacteria, however Clostridia, Opitutae and bacteria related with Betaproteobacteria, were stimulated denoting their tolerance. Altogether, these data indicate that crop irrigation using cyanotoxins containing water might alter the rhizosphere functioning.

  7. Chemical modification and degradation of atrazine in Medicago sativa through multiple pathways.

    Science.gov (United States)

    Zhang, Jing Jing; Lu, Yi Chen; Yang, Hong

    2014-10-08

    Atrazine is a member of the triazine herbicide family intensively used to control weeds for crop production. In this study, atrazine residues and its degraded products in alfalfa (Medicago sativa) were characterized using UPLC-TOF-MS/MS. Most of atrazine absorbed in plants was found as chemically modified derivatives like deisopropylated atrazine (DIA), dehydrogenated atrazine (DHA), or methylated atrazine (MEA), and some atrazine derivatives were conjugated through different functional groups such as sugar, glutathione, and amino acids. Interestingly, the specific conjugates DHA+hGSH (homoglutathione) and MEA-HCl+hGSH in alfalfa were detected. These results suggest that atrazine in alfalfa can be degraded through different pathways. The increased activities of glycosyltransferase and glutathione S-transferase were determined to support the atrazine degradation models. The outcome of the work uncovered the detailed mechanism for the residual atrazine accumulation and degradation in alfalfa and will help to evaluate whether the crop is suitable to be cultivated in the atrazine-polluted soil.

  8. Characterization of a novel Medicago sativa NAC transcription factor gene involved in response to drought stress.

    Science.gov (United States)

    Wang, Yong Xin

    2013-11-01

    Relying on the regulation of transcription factors, plants resist to various abiotic and biotic stresses. NAC (NAM, ATAF1/2, CUC2) are one of the largest families of plant-specific transcription factors and known to play important roles in plant development and response to environmental stresses. A new NAC gene was cloned on the basis of 503 bp EST fragment from the SSH cDNA library of Medicago sativa. It was 1,115 bp including an 816 bp ORF and encodes 271 amino acids. A highly conserved region is located from the 7th amino acid to the 315th amino acid in its N-terminal domain. The NAC protein is subcellularly localized in the nucleus of onion epidemical cells and possible functions as a transcription factor. The relative quantitative real-time RT-PCR was performed at different stress time. The results revealed that the transcription expression of NAC gene could be induced by drought, high salinity and ABA. The transgenic Arabidopsis with NAC gene has the drought tolerance better than the wild-type.

  9. In silico identification of transcription factors in Medicago sativa using available transcriptomic resources.

    Science.gov (United States)

    Postnikova, Olga A; Shao, Jonathan; Nemchinov, Lev G

    2014-06-01

    Transcription factors (TFs) are proteins that govern organismal development and response to the environment by regulating gene expression. Information on the amount and diversity of TFs within individual plant species is critical for understanding of their biological roles and evolutionary history across the plant kingdom. Currently, only scattered information on separate TFs is available for alfalfa, the most extensively cultivated forage legume in the world. In the meantime, several large transcriptomic resources that can be used to identify and characterize alfalfa TF genes are freely accessible online. In this study, we have performed an in silico analysis of transcriptome data generated in our laboratory and publicly acquirable from other sources to reveal and systematize alfalfa transcription factors. Transcriptome-wide mining enabled prediction of 983 TFs along with their sequence features and putative phylogenies of the largest families. All data were assembled into a simple open-access database named AlfalfaTFDB ( http://plantpathology.ba.ars.usda.gov/alfalfatfdb.html ). Transcriptomic analysis used in this work represents an effective approach for the identification of TF genes in plants with incomplete genomes, such as alfalfa. Integrated TF repertoires of Medicago sativa will provide an important tool for studying regulation of gene expression in other complex non-model species of agricultural significance.

  10. Transcriptome analysis of Glomus mosseae/Medicago sativa mycorrhiza on atrazine stress.

    Science.gov (United States)

    Song, Fuqiang; Li, Jize; Fan, Xiaoxu; Zhang, Quan; Chang, Wei; Yang, Fengshan; Geng, Gui

    2016-02-02

    Arbuscular mycorrhizal fungi (AMF) protect host plants against diverse biotic and abiotic stresses, and promote biodegradation of various contaminants. In this study effect of Glomus mosseae/Medicago sativa mycorrhiza on atrazine degradation was investigated. It was observed that the atrazine degradation rates with any addition level in mycorrhizal treatments were all significantly higher than those in non-mycorrhizal treatments. When atrazine was applied at 20 mg kg(-1), the removal efficiency was up to 74.65%. Therefore, G. mosseae can be considered as ideal inhabitants of technical installations to facilitate phytoremediation. Furthermore, a total of 10.4 Gb was used for de novo transcriptome assembly, resulting in a comprehensive data set for the identification of genes corresponding to atrazine stress in the AM association. After comparative analysis with edgeR, a total of 2,060 differential expressed genes were identified, including 570 up-regulated genes and 1490 down-regulated genes. After excluding 'function unknown' and 'general function predictions only' genes, 172 up-regulated genes were obtained. The differentially expressed genes in AM association with and without atrazine stress were associated with molecular processes/other proteins, zinc finger protein, intracellular/extracellular enzymes, structural proteins, anti-stress/anti-disease protein, electron transport-related protein, and plant growth associated protein. Our results not only prove AMF has important ecological significance on atrazine degradation but also provide evidence for the molecular mechanisms of atrazine degradation by AMF.

  11. Role of LONELY GUY genes in indeterminate nodulation on Medicago truncatula.

    Science.gov (United States)

    Mortier, Virginie; Wasson, Anton; Jaworek, Pavel; De Keyser, Annick; Decroos, Martijn; Holsters, Marcelle; Tarkowski, Petr; Mathesius, Ulrike; Goormachtig, Sofie

    2014-04-01

    LONELY GUY (LOG) genes encode cytokinin riboside 5'-monophosphate phosphoribohydrolases and are directly involved in the activation of cytokinins. To assess whether LOG proteins affect the influence of cytokinin on nodulation, we studied two LOG genes of Medicago truncatula. Expression analysis showed that MtLOG1 and MtLOG2 were upregulated during nodulation in a CRE1-dependent manner. Expression was mainly localized in the dividing cells of the nodule primordium. In addition, RNA interference revealed that MtLOG1 is involved in nodule development and that the gene plays a negative role in lateral root development. Ectopic expression of MtLOG1 resulted in a change in cytokinin homeostasis, triggered cytokinin-inducible genes and produced roots with enlarged vascular tissues and shortened primary roots. In addition, those 35S:LOG1 roots also displayed fewer nodules than the wild-type. This inhibition in nodule formation was local, independent of the SUPER NUMERIC NODULES gene, but coincided with an upregulation of the MtCLE13 gene, encoding a CLAVATA3/EMBRYO SURROUNDING REGION peptide. In conclusion, we demonstrate that in M. truncatula LOG proteins might be implicated in nodule primordium development and lateral root formation. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  12. Molecular Signals Controlling the Inhibition of Nodulation by Nitrate in Medicago truncatula.

    Science.gov (United States)

    van Noorden, Giel E; Verbeek, Rob; Dinh, Quy Dung; Jin, Jian; Green, Alexandra; Ng, Jason Liang Pin; Mathesius, Ulrike

    2016-07-02

    The presence of nitrogen inhibits legume nodule formation, but the mechanism of this inhibition is poorly understood. We found that 2.5 mM nitrate and above significantly inhibited nodule initiation but not root hair curling in Medicago trunatula. We analyzed protein abundance in M. truncatula roots after treatment with either 0 or 2.5 mM nitrate in the presence or absence of its symbiont Sinorhizobium meliloti after 1, 2 and 5 days following inoculation. Two-dimensional gel electrophoresis combined with mass spectrometry was used to identify 106 differentially accumulated proteins responding to nitrate addition, inoculation or time point. While flavonoid-related proteins were less abundant in the presence of nitrate, addition of Nod gene-inducing flavonoids to the Sinorhizobium culture did not rescue nodulation. Accumulation of auxin in response to rhizobia, which is also controlled by flavonoids, still occurred in the presence of nitrate, but did not localize to a nodule initiation site. Several of the changes included defense- and redox-related proteins, and visualization of reactive oxygen species indicated that their induction in root hairs following Sinorhizobium inoculation was inhibited by nitrate. In summary, the presence of nitrate appears to inhibit nodulation via multiple pathways, including changes to flavonoid metabolism, defense responses and redox changes.

  13. Two Direct Targets of Cytokinin Signaling Regulate Symbiotic Nodulation in Medicago truncatula[W][OA

    Science.gov (United States)

    Ariel, Federico; Brault-Hernandez, Marianne; Laffont, Carole; Huault, Emeline; Brault, Mathias; Plet, Julie; Moison, Michael; Blanchet, Sandrine; Ichanté, Jean Laurent; Chabaud, Mireille; Carrere, Sébastien; Crespi, Martin; Chan, Raquel L.; Frugier, Florian

    2012-01-01

    Cytokinin regulates many aspects of plant development, and in legume crops, this phytohormone is necessary and sufficient for symbiotic nodule organogenesis, allowing them to fix atmospheric nitrogen. To identify direct links between cytokinins and nodule organogenesis, we determined a consensus sequence bound in vitro by a transcription factor (TF) acting in cytokinin signaling, the nodule-enhanced Medicago truncatula Mt RR1 response regulator (RR). Among genes rapidly regulated by cytokinins and containing this so-called RR binding site (RRBS) in their promoters, we found the nodulation-related Type-A RR Mt RR4 and the Nodulation Signaling Pathway 2 (NSP2) TF. Site-directed mutagenesis revealed that RRBS cis-elements in the RR4 and NSP2 promoters are essential for expression during nodule development and for cytokinin induction. Furthermore, a microRNA targeting NSP2 (miR171 h) is also rapidly induced by cytokinins and then shows an expression pattern anticorrelated with NSP2. Other primary targets regulated by cytokinins depending on the Cytokinin Response1 (CRE1) receptor were a cytokinin oxidase/dehydrogenase (CKX1) and a basic Helix-Loop-Helix TF (bHLH476). RNA interference constructs as well as insertion of a Tnt1 retrotransposon in the bHLH gene led to reduced nodulation. Hence, we identified two TFs, NSP2 and bHLH476, as direct cytokinin targets acting at the convergence of phytohormonal and symbiotic cues. PMID:23023168

  14. Abscisic acid coordinates nod factor and cytokinin signaling during the regulation of nodulation in Medicago truncatula.

    Science.gov (United States)

    Ding, Yiliang; Kalo, Peter; Yendrek, Craig; Sun, Jongho; Liang, Yan; Marsh, John F; Harris, Jeanne M; Oldroyd, Giles E D

    2008-10-01

    Nodulation is tightly regulated in legumes to ensure appropriate levels of nitrogen fixation without excessive depletion of carbon reserves. This balance is maintained by intimately linking nodulation and its regulation with plant hormones. It has previously been shown that ethylene and jasmonic acid (JA) are able to regulate nodulation and Nod factor signal transduction. Here, we characterize the nature of abscisic acid (ABA) regulation of nodulation. We show that application of ABA inhibits nodulation, bacterial infection, and nodulin gene expression in Medicago truncatula. ABA acts in a similar manner as JA and ethylene, regulating Nod factor signaling and affecting the nature of Nod factor-induced calcium spiking. However, this action is independent of the ethylene signal transduction pathway. We show that genetic inhibition of ABA signaling through the use of a dominant-negative allele of ABSCISIC ACID INSENSITIVE1 leads to a hypernodulation phenotype. In addition, we characterize a novel locus of M. truncatula, SENSITIVITY TO ABA, that dictates the sensitivity of the plant to ABA and, as such, impacts the regulation of nodulation. We show that ABA can suppress Nod factor signal transduction in the epidermis and can regulate cytokinin induction of the nodule primordium in the root cortex. Therefore, ABA is capable of coordinately regulating the diverse developmental pathways associated with nodule formation and can intimately dictate the nature of the plants' response to the symbiotic bacteria.

  15. Identification and expression analysis of multiple FRO gene copies in Medicago truncatula.

    Science.gov (United States)

    Del C Orozco-Mosqueda, Ma; Santoyo, G; Farías-Rodríguez, R; Macías-Rodríguez, L; Valencia-Cantero, E

    2012-12-17

    Iron (Fe) is an essential element for plant growth. Commonly, this element is found in an oxidized form in soil, which is poorly available for plants. Therefore, plants have evolved ferric-chelate reductase enzymes (FRO) to reduce iron into a more soluble ferrous form. Fe scarcity in plants induce the FRO enzyme activity. Although the legume Medicago truncatula has been employed as a model for FRO activity studies, only one copy of the M. truncatula MtFRO1 gene has been characterized so far. In this study, we identified multiple gene copies of the MtFRO gene in the genome of M. truncatula by an in silico search, using BLAST analysis in the database of the M. truncatula Genome Sequencing Project and the National Center for Biotechnology Information, and also determined whether they are functional. We identified five genes apart from MtFRO1, which had been already characterized. All of the MtFRO genes exhibited high identity with homologous FRO genes from Lycopersicon esculentum, Citrus junos and Arabidopsis thaliana. The gene copies also presented characteristic conserved FAD and NADPH motifs, transmembrane regions and oxidoreductase signature motifs. We also detected expression in five of the putative MtFRO sequences by semiquantitative RT-PCR analysis, performed with mRNA from root and shoot tissues. Iron scarcity might be a condition for an elevated expression of the MtFRO genes observed in different M. truncatula tissues.

  16. The Current Status, Problems, and Prospects of Alfalfa (Medicago sativa L. Breeding in China

    Directory of Open Access Journals (Sweden)

    Shangli Shi

    2017-01-01

    Full Text Available This paper reviews the current status, methodology, achievements, and prospects of alfalfa (Medicago sativa L. breeding in China. There are 77 cultivars that have been registered in the country, these include 36 cultivars bred through breeding programs, 17 introduced from overseas, 5 domesticated from wild ecotypes, and 19 through regional collection/breeding programs. Cultivars have been selected for cold resistance, disease resistance, salt tolerance, grazing tolerance, high yield, and early maturity. Most of these cultivars have been developed through conventional breeding techniques, such as selective and cross breeding, and some are now being evaluated that have been developed through the application of transgenic technology. The major problems for alfalfa breeding in China include low success rate, slow progress to breed resistant varieties, lack of breeding materials and their systematic collection, storage and evaluation, lack of advanced breeding techniques, and low adoption rate of new cultivars. There are gaps in alfalfa breeding between China and the developed world. Improvement of alfalfa breeding techniques, development of cultivars with adaptations to different regions within China, and the protection and utilization of alfalfa germplasm resources have been identified as major strategies to improve the efficiency of alfalfa breeding in China.

  17. Unveiling common responses of Medicago truncatula to appropriate and inappropriate rust species

    Directory of Open Access Journals (Sweden)

    Maria Carlota eVaz Patto

    2014-11-01

    Full Text Available Little is known about the nature of effective defense mechanisms in legumes to pathogens of remotely related plant species. Some rust species are among pathogens with broad host range causing dramatic losses in various crop plants. To understand and compare the different host and nonhost resistance responses of legume species against rusts, we characterized the reaction of the model legume Medicago truncatula to one appropriate (Uromyces striatus and two inappropriate (U. viciae-fabae and U. lupinicolus rusts. We found that similar pre and post-haustorial mechanisms of resistance appear to be operative in M. truncatula against appropriate and inappropriate rust fungus. The appropriate U. striatus germinated better on M. truncatula accessions then the inappropriate U. viciae-fabae and U. lupinicolus, but once germinated, germ tubes of the three rusts had a similar level of success in finding stomata and forming an appressoria over a stoma. However responses to different inappropriate rust species also showed some specificity, suggesting a combination of non specific and specific responses underlying this legume nonhost resistance to rust fungi. Further genetic and expression analysis studies will contribute to the development of the necessary molecular tools to use the present information on host and nonhost resistance mechanisms to breed for broad-spectrum resistance to rust in legume species.

  18. api, A novel Medicago truncatula symbiotic mutant impaired in nodule primordium invasion.

    Science.gov (United States)

    Teillet, Alice; Garcia, Joseph; de Billy, Françoise; Gherardi, Michèle; Huguet, Thierry; Barker, David G; de Carvalho-Niebel, Fernanda; Journet, Etienne-Pascal

    2008-05-01

    Genetic approaches have proved to be extremely useful in dissecting the complex nitrogen-fixing Rhizobium-legume endosymbiotic association. Here we describe a novel Medicago truncatula mutant called api, whose primary phenotype is the blockage of rhizobial infection just prior to nodule primordium invasion, leading to the formation of large infection pockets within the cortex of noninvaded root outgrowths. The mutant api originally was identified as a double symbiotic mutant associated with a new allele (nip-3) of the NIP/LATD gene, following the screening of an ethylmethane sulphonate-mutagenized population. Detailed characterization of the segregating single api mutant showed that rhizobial infection is also defective at the earlier stage of infection thread (IT) initiation in root hairs, as well as later during IT growth in the small percentage of nodules which overcome the primordium invasion block. Neither modulating ethylene biosynthesis (with L-alpha-(2-aminoethoxyvinylglycine or 1-aminocyclopropane-1-carboxylic acid) nor reducing ethylene sensitivity in a skl genetic background alters the basic api phenotype, suggesting that API function is not closely linked to ethylene metabolism or signaling. Genetic mapping places the API gene on the upper arm of the M. truncatula linkage group 4, and epistasis analyses show that API functions downstream of BIT1/ERN1 and LIN and upstream of NIP/LATD and the DNF genes.

  19. Legume adaptation to sulfur deficiency revealed by comparing nutrient allocation and seed traits in Medicago truncatula.

    Science.gov (United States)

    Zuber, Hélène; Poignavent, Germain; Le Signor, Christine; Aimé, Delphine; Vieren, Eric; Tadla, Charlène; Lugan, Raphaël; Belghazi, Maya; Labas, Valérie; Santoni, Anne-Lise; Wipf, Daniel; Buitink, Julia; Avice, Jean-Christophe; Salon, Christophe; Gallardo, Karine

    2013-12-01

    Reductions in sulfur dioxide emissions and the use of sulfur-free mineral fertilizers are decreasing soil sulfur levels and threaten the adequate fertilization of most crops. To provide knowledge regarding legume adaptation to sulfur restriction, we subjected Medicago truncatula, a model legume species, to sulfur deficiency at various developmental stages, and compared the yield, nutrient allocation and seed traits. This comparative analysis revealed that sulfur deficiency at the mid-vegetative stage decreased yield and altered the allocation of nitrogen and carbon to seeds, leading to reduced levels of major oligosaccharides in mature seeds, whose germination was dramatically affected. In contrast, during the reproductive period, sulfur deficiency had little influence on yield and nutrient allocation, but the seeds germinated slowly and were characterized by low levels of a biotinylated protein, a putative indicator of germination vigor that has not been previously related to sulfur nutrition. Significantly, plants deprived of sulfur at an intermediary stage (flowering) adapted well by remobilizing nutrients from source organs to seeds, ensuring adequate quantities of carbon and nitrogen in seeds. This efficient remobilization of photosynthates may be explained by vacuolar sulfate efflux to maintain leaf metabolism throughout reproductive growth, as suggested by transcript and metabolite profiling. The seeds from these plants, deprived of sulfur at the floral transition, contained normal levels of major oligosaccharides but their germination was delayed, consistent with low levels of sucrose and the glycolytic enzymes required to restart seed metabolism during imbibition. Overall, our findings provide an integrative view of the legume response to sulfur deficiency.

  20. Molecular mobility in Medicago truncatula seed during early stage of germination: Neutron scattering and NMR investigations

    Energy Technology Data Exchange (ETDEWEB)

    Falourd, Xavier [UR1268 Biopolymères Interactions Assemblages, INRA, F-44316 Nantes (France); Natali, Francesca [CNR-IOM-OGG, c/o Institut Laue-Langevin, 6 rue Jules Horowitz, BP 156, 38042 Grenoble Cedex 9 (France); Institut Laue-Langevin, 6 rue Jules Horowitz, BP 156, 38042 Grenoble Cedex 9 (France); Peters, Judith [Institut Laue-Langevin, 6 rue Jules Horowitz, BP 156, 38042 Grenoble Cedex 9 (France); Université Joseph Fourier UFR PhITEM, BP 53, 38041 Grenoble Cedex 9 (France); Institut de Biologie Structurale, 41 rue Jules Horowitz, 38027 Grenoble Cedex 1 (France); Foucat, Loïc, E-mail: Loic.Foucat@nantes.inra.fr [UR1268 Biopolymères Interactions Assemblages, INRA, F-44316 Nantes (France)

    2014-01-15

    Highlights: • Neutron scattering and NMR approaches were used to characterize seed germination. • A parallel between macromolecular motions and water dynamics was established. • Freezing/thawing cycle revealed a hysteresis connected to the seed hydration level. - Abstract: First hours of Medicago truncatula (MT) seeds germination were investigated using elastic incoherent neutron scattering (EINS) and nuclear magnetic resonance (NMR), to follow respectively how macromolecular motions and water mobility evolve when water permeates into the seed. From EINS results, it was shown that there is an increase in macromolecular mobility with the water uptake. Changes in NMR relaxation parameters reflected microstructural changes associated with the recovery of the metabolic processes. The EINS investigation of the effect of temperature on macromolecular motions showed that there is a relationship between the amount of water in the seeds and the effect of freezing–thawing cycle. The NMR relaxometry results obtained at 253 K allowed establishing possible link between the freezing of water molecules tightly bound to macromolecules and their drastic motion restriction around 250 K, as observed with EINS at the highest water content.

  1. MtVRN2 is a Polycomb VRN2-like gene which represses the transition to flowering in the model legume Medicago truncatula.

    Science.gov (United States)

    Jaudal, Mauren; Zhang, Lulu; Che, Chong; Hurley, Daniel G; Thomson, Geoffrey; Wen, Jiangqi; Mysore, Kirankumar S; Putterill, Joanna

    2016-04-01

    Optimising the timing of flowering contributes to successful sexual reproduction and yield in agricultural plants. FLOWERING LOCUS T (FT) genes, first identified in Arabidopsis thaliana (Arabidopsis), promote flowering universally, but the upstream flowering regulatory pathways can differ markedly among plants. Flowering in the model legume, Medicago truncatula (Medicago) is accelerated by winter cold (vernalisation) followed by long day (LD) photoperiods leading to elevated expression of the floral activator, FT-like gene FTa1. However, Medicago, like some other plants, lacks the activator CONSTANS (CO) and the repressor FLOWERING LOCUS C (FLC) genes which directly regulate FT and are key to LD and vernalisation responses in Arabidopsis. Conversely, Medicago has a VERNALISATION2-LIKE VEFS-box gene (MtVRN2). In Arabidopsis AtVRN2 is a key member of a Polycomb complex involved in stable repression of Arabidopsis FLC after vernalisation. VRN2-like genes have been identified in other eudicot plants, but their function has never been reported. We show that Mtvrn2 mutants bypass the need for vernalisation for early flowering in LD conditions in Medicago. Investigation of the underlying mechanism by transcriptome analysis reveals that Mtvrn2 mutants precociously express FTa1 and other suites of genes including floral homeotic genes. Double-mutant analysis indicates that early flowering is dependent on functional FTa1. The broad significance of our study is that we have demonstrated a function for a VRN2-like VEFS gene beyond the Brassicaceae. In particular, MtVRN2 represses the transition to flowering in Medicago by regulating the onset of expression of the potent floral activator, FTa1.

  2. 苜蓿属植物分类研究进展分析%Status of Germplasm Classifications for Genus Medicago

    Institute of Scientific and Technical Information of China (English)

    卢欣石

    2009-01-01

    回顾了近百年世界苜蓿属(Medicago L.)植物分类的不同结果和演变历程,重点讨论了中国和西方学者对苜蓿属植物分类系统的主要分歧.依据中国学者的分类系统,苜蓿(Medicago sativa Linn)、胡卢巴(Cermmon Fenupreek)、扁蓿豆(Huthenian medica)、黑荚豆(Medicago varia Martyn)等植物种被分别归属于苜蓿属、胡卢巴属(Trigonella L.)、扁蓿豆属(Melissitus Medik.)和黑荚豆属(Turucania),按照西方学者的分类系统,均被列入苜蓿属,并提出紫花苜蓿(Medicago sativa)复合体的概念,将紫花苜蓿、黄花苜蓿(Medicago falcata)、杂花苜蓿(Medicago Httyenica (Lnn.) Trautv)同归为紫花苜蓿亚种.文章建议为了充分挖掘中国苜蓿种质资源的优势,发挥优异基因的改良作用,有必要对中国目前的遗传资源基因库的现状和分类系统在分子水平上进行复核和探讨.

  3. Hybrid microelectronic technology

    Science.gov (United States)

    Moran, P.

    Various areas of hybrid microelectronic technology are discussed. The topics addressed include: basic thick film processing, thick film pastes and substrates, add-on components and attachment methods, thin film processing, and design of thick film hybrid circuits. Also considered are: packaging hybrid circuits, automating the production of hybrid circuits, application of hybrid techniques, customer's view of hybrid technology, and quality control and assurance in hybrid circuit production.

  4. ABA-Mediated Inhibition of Germination Is Related to the Inhibition of Genes Encoding Cell-Wall Biosynthetic and Architecture:Modifying Enzymes and Structural Proteins in Medicago truncatula Embryo Axis

    Institute of Scientific and Technical Information of China (English)

    Christine Gimeno-Gilles; Eric Lelièvre; Laure Viau; Mustafa Malik-Ghulam; Claudie Ricoult; Andreas Niebel; Nathalie Leduc; Anis M. Limami

    2009-01-01

    Radicle emergence and reserves mobilization are two distinct programmes that are thought to control germination. Both programs are influenced by abscissic acid (ABA) but how this hormone controls seed germination is still poorly known. Phenotypic and microscopic observations of the embryo axis of Medicago truncatula during germination in mitotic inhibition condition triggered by 10 μM oryzalin showed that cell division was not required to allow radicle emergence. A suppressive subtractive hybridization showed that more than 10% of up-regulated genes in the embryo axis encoded proteins related to cell-wall biosynthesis. The expression of α-expansins, pectin-esterase, xylogucan-endotransglycosidase, cellulose synthase, and extensins was monitored in the embryo axis of seeds germinated on water, constant and transitory ABA. These genes were overexpressed before completion of germination in the control and strongly inhibited by ABA. The expression was re-established in the ABA transitory-treatment after the seeds were transferred back on water and proceeded to germination. This proves these genes as contributors to the completion of germination and strengthen the idea that cell-wall loosening and remodeling in relation to cell expansion in the embryo axis is a determinant feature in germination. Our results also showed that ABA controls germination through the control of radicle emergence, namely by inhibiting cell-wall loosening and expansion.

  5. Expression of the plastid-located glutamine synthetase of Medicago truncatula. Accumulation of the precursor in root nodules reveals an in vivo control at the level of protein import into plastids.

    Science.gov (United States)

    Melo, Paula M; Lima, Lígia M; Santos, Isabel M; Carvalho, Helena G; Cullimore, Julie V

    2003-05-01

    In this paper, we report the cloning and characterization of the plastid-located glutamine synthetase (GS) of Medicago truncatula Gaertn (MtGS2). A cDNA was isolated encoding a GS2 precursor polypeptide of 428 amino acids composing an N-terminal transit peptide of 49 amino acids. Expression analysis, by Westerns and by northern hybridization, revealed that MtGS2 is expressed in both photosynthetic and non-photosynthetic organs. Both transcripts and proteins of MtGS2 were detected in substantial amounts in root nodules, suggesting that the enzyme might be performing some important role in this organ. Surprisingly, about 40% of the plastid GS in nodules occurred in the non-processed precursor form (preGS2). This precursor was not detected in any other organ studied and moreover was not observed in non-fixing nodules. Cellular fractionation of nodule extracts revealed that preGS2 is associated with the plastids and that it is catalytically inactive. Immunogold electron microscopy revealed a frequent coincidence of GS with the plastid envelope. Taken together, these results suggest a nodule-specific accumulation of the GS2 precursor at the surface of the plastids in nitrogen-fixing nodules. These results may reflect a regulation of GS2 activity in relation to nitrogen fixation at the level of protein import into nodule plastids.

  6. Effect of UV-C on Drought Tolerance of Alfalfa (Medicago sativa) Callus

    OpenAIRE

    Ali A. Ehsanpour; Roya Razavizadeh

    2005-01-01

    Water stress and unfavorable climate decrease the growth and development of plant globally. Medicago is a valuable plant as a source of food for animal, foliage and for medicine. Since, Iran is located in a dry area; consequently, the study of plant responses to water stress is important. In this research UV-C radiation was used to induce physiological and genetic changes in alfalfa callus. In vitro grown calluses of M. sativa were exposed to UV-C for 0, 15, 30 and 60 min and then, were trans...

  7. 转基因苜蓿的研究进展%Advances in the Research of Transgenic Medicago sativa

    Institute of Scientific and Technical Information of China (English)

    李文桂; 陈雅棠

    2009-01-01

    苜蓿(Medicago sativa)是一种优良的豆科牧草,应用基因工程技术对苜蓿进行开发和改造已成为国内外研究的热点.本文综述了病毒、细菌、寄生虫、抗逆基因、品质改良基因、抗除草剂基因、单克隆抗体和工业原料等转基因苜蓿的研究进展.

  8. Mineral accumulation in vegetative and reproductive tissues during seed development in Medicago truncatula

    Directory of Open Access Journals (Sweden)

    Christina B. Garcia

    2015-08-01

    Full Text Available Enhancing nutrient density in legume seeds is one of several strategies being explored to improve the nutritional quality of the food supply. In order to develop crop varieties with increased seed mineral concentration, a more detailed understanding of mineral translocation within the plant is required. By studying mineral accumulation in different organs within genetically diverse members of the same species, it may be possible to identify variable traits that modulate seed mineral concentration. We utilized two ecotypes (A17 and DZA315.16 of the model legume, Medicago truncatula, to study dry mass and mineral accumulation in the leaves, pod walls, and seeds during reproductive development. The pod wall dry mass was significantly different between the two ecotypes beginning at 12 days after pollination, whereas there was no significant difference in the average dry mass of individual seeds between the two ecotypes at any time point. There were also no significant differences in leaf dry mass between ecotypes; however, we observed expansion of A17 leaves during the first 21 days of pod development, while DZA315.16 leaves did not display a significant increase in leaf area. Mineral profiling of the leaves, pod walls, and seeds highlighted differences in accumulation patterns among minerals within each tissue as well as genotypic differences with respect to individual minerals. Because there were differences in the average seed number per pod, the total seed mineral content per pod was generally higher in A17 than DZA315.16. In addition, mineral partitioning to the seeds tended to be higher in A17 pods. These data revealed that mineral retention within leaves and/or pod walls might attenuate mineral accumulation within the seeds. As a result, strategies to increase seed mineral content should include approaches that will enhance export from these tissues.

  9. Proteomic Identification of Differentially Expressed Proteins during Alfalfa (Medicago sativa L.) Flower Development

    Science.gov (United States)

    Chen, Lingling; Chen, Quanzhu; Zhu, Yanqiao; Hou, Longyu; Mao, Peisheng

    2016-01-01

    Flower development, pollination, and fertilization are important stages in the sexual reproduction process of plants; they are also critical steps in the control of seed formation and development. During alfalfa (Medicago sativa L.) seed production, some distinct phenomena such as a low seed setting ratio, serious flower falling, and seed abortion commonly occur. However, the causes of these phenomena are complicated and largely unknown. An understanding of the mechanisms that regulate alfalfa flowering is important in order to increase seed yield. Hence, proteomic technology was used to analyze changes in protein expression during the stages of alfalfa flower development. Flower samples were collected at pre-pollination (S1), pollination (S2), and the post-pollination senescence period (S3). Twenty-four differentially expressed proteins were successfully identified, including 17 down-regulated in pollinated flowers, one up-regulated in pollinated and senesced flowers, and six up-regulated in senesced flowers. The largest proportions of the identified proteins were involved in metabolism, signal transduction, defense response, oxidation reduction, cell death, and programmed cell death (PCD). Their expression profiles demonstrated that energy metabolism, carbohydrate metabolism, and amino acid metabolism provided the nutrient foundation for pollination in alfalfa. Furthermore, there were three proteins involved in multiple metabolic pathways: dual specificity kinase splA-like protein (kinase splALs), carbonic anhydrase, and NADPH: quinone oxidoreductase-like protein. Expression patterns of these proteins indicated that MAPK cascades regulated multiple processes, such as signal transduction, stress response, and cell death. PCD also played an important role in the alfalfa flower developmental process, and regulated both pollination and flower senescence. The current study sheds some light on protein expression profiles during alfalfa flower development and

  10. Proteomic Identification of Differentially Expressed Proteins during Alfalfa (Medicago sativa L.) Flower Development.

    Science.gov (United States)

    Chen, Lingling; Chen, Quanzhu; Zhu, Yanqiao; Hou, Longyu; Mao, Peisheng

    2016-01-01

    Flower development, pollination, and fertilization are important stages in the sexual reproduction process of plants; they are also critical steps in the control of seed formation and development. During alfalfa (Medicago sativa L.) seed production, some distinct phenomena such as a low seed setting ratio, serious flower falling, and seed abortion commonly occur. However, the causes of these phenomena are complicated and largely unknown. An understanding of the mechanisms that regulate alfalfa flowering is important in order to increase seed yield. Hence, proteomic technology was used to analyze changes in protein expression during the stages of alfalfa flower development. Flower samples were collected at pre-pollination (S1), pollination (S2), and the post-pollination senescence period (S3). Twenty-four differentially expressed proteins were successfully identified, including 17 down-regulated in pollinated flowers, one up-regulated in pollinated and senesced flowers, and six up-regulated in senesced flowers. The largest proportions of the identified proteins were involved in metabolism, signal transduction, defense response, oxidation reduction, cell death, and programmed cell death (PCD). Their expression profiles demonstrated that energy metabolism, carbohydrate metabolism, and amino acid metabolism provided the nutrient foundation for pollination in alfalfa. Furthermore, there were three proteins involved in multiple metabolic pathways: dual specificity kinase splA-like protein (kinase splALs), carbonic anhydrase, and NADPH: quinone oxidoreductase-like protein. Expression patterns of these proteins indicated that MAPK cascades regulated multiple processes, such as signal transduction, stress response, and cell death. PCD also played an important role in the alfalfa flower developmental process, and regulated both pollination and flower senescence. The current study sheds some light on protein expression profiles during alfalfa flower development and

  11. Antifungal activity of saponins originated from Medicago hybrida against some ornamental plant pathogens

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    Alicja Saniewska

    2012-12-01

    Full Text Available Antifungal activity of total saponins originated from roots of Medicago hybrida (Pourret Trautv. were evaluated in vitro against six pathogenic fungi and eight individual major saponin glycosides were tested against one of the most susceptible fungi. The total saponins showed fungitoxic effect at all investigated concentrations (0.01%, 0.05% and 0.1% but their potency was different for individual fungi. The highest saponin concentration (0.1% was the most effective and the inhibition of Fusarium oxysporum f. sp. callistephi, Botrytis cinerea, Botrytis tulipae, Phoma narcissi, Fusarium oxysporum f. sp. narcissi was 84.4%, 69.9%, 68.6%, 57.2%, 55.0%, respectively. While Fusarium oxysporum Schlecht., a pathogen of Muscari armeniacum, was inhibited by 9.5% only. Eight major saponin glycosides isolated from the total saponins of M. hybrida roots were tested against the mycelium growth of Botrytis tulipae. The mycelium growth of the pathogen was greatly inhibited by hederagenin 3-O-β-D-glucopyranoside and medicagenic acid 3-O-β-D-glucopyranoside. Medicagenic acid 3-O-β-D-glucuronopyranosyl-28-O-β-D-glucopyranoside and oleanolic acid 3-O-[β-D-glucuronopyranosyl(1→2-α-L-galactopyranosyl]-28-O-β-D-glucopyranoside showed low fungitoxic activity. Medicagenic acid 3-O-a-D-glucopyranosyl- 28-O-β-D-glucopyranoside, hederagenin 3-O-[α-L- hamnopyranosyl(1→2-β-D-glucopyranosyl(1→2-β-D-glucopyranosyl]- 28-O-α-D-glucopyranoside and hederagenin 3-O-β-D-glucuronopyranosyl-28-O-β-D- lucopyranoside did not limit or only slightly inhibited growth of the tested pathogen. While 2β, 3β-dihydroxyolean-12 ene-23-al-28-oic acid 3-O-β-D-glucuronopyranosyl-28-O-β-D-glucopyranoside slightly stimulated mycelium growth of B. tulipae.

  12. Combined effects of ozone and water stress on alfalfa growth and yield. [Medicago sativa L

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    Temple, P.J.; Benoit, L.F.; Lennox, R.W.; Reagan, C.A.; Taylor, O.C.

    A 2-yr study (1984 and 1985) designed to determine the interactive effects of ozone (O/sub 3/) and water stress on alfalfa (Medicago sativa L. cv. WL-514) was conducted in Shafter, CA. The objectives of this study were to develop O/sub 3/ dose-yield response functions for alfalfa, to determine how water stress could alter these functions, and to describe the cumulative effects of multiple-year exposures to O/sub 3/ on this perennial crop. Field-grown alfalfa, raised under normally irrigated (NI) or water-stressed (WS) conditions in open-top chambers, was exposed to five O/sub 3/ treatments including charcoal-filtered (CF), nonfiltered (NF), and NF plus an additional 33, 67, or 100% of ambient O/sub 3/ concentrations. Ambient O/sub 3/ concentrations averaged 0.049 ..mu..L L/sup -1/ in 1984 and 0.042 ..mu..L L/sup -1/ in 1985 for the seasonal 12-h (0900-2100) means from April to October. Water stress reduced total seasonal yield about 10% in 1984 and 27% in 1985. Ozone significantly reduced yields in both years, and the interactions between O/sub 3/ and water stress was statistically significant in 1985 and for combined 1984 and 1985 years. Ozone dose-alfalfa yield loss functions were homogeneous between 1984 and 1985 and no evidence of a cumulative effect of multiple-year exposure to O/sub 3/ was found on top growth. However, crown (underground stem) weights were significantly reduced by O/sub 3/, suggesting that continued exposure to O/sub 3/ could shorten the productive life of alfalfa stands, in addition to its effect on yield.

  13. Weed control in dormant alfalfa (Medicago sativa L. with active ingredients’ metribuzin, imazetapyr and pronamide

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    Zvonko Pacanoski

    2017-03-01

    Full Text Available Field trials were conducted during 2008 – 2010 to evaluate weed control in dormant alfalfa (Medicago sativa L. with metribuzin, imazetapyr and pronamide. The weed population in all experimental years was consisted mainly of annual winter and spring grass and broadleaf weeds, and some perennial weeds. The number of weed species and weed density increased with the years of alfalfa growing, from second to the fourth year. Weed density in the untreated control plots was 201.0, 217.2 and 240.5 plants per m2 in 2008, 2009 and 2010, respectively. The most dominant weeds were Anthemis cotula, Capsell bursa-pastoris and Taraxacum officinale in 2008, Alopecurus myosuroides and Poa pratensis in 2009 and Millium vernale and Arabidopsis thaliana in 2010. Efficacy of herbicides in control of weeds was ranged of 91.8% (pronamide to 98.4% (metribuzin 1.0 kg*ha-1 in 2008, 93.1% (imazetapyr to 97.3% (metribuzin 1.0 kg*ha-1 in 2009 and 92.1% (imazetapyr to 97.3% (metribuzin 1.0 kg*ha-1 in 2010, respectively. Efficacy of herbicides in control of prevailing weeds during the 3 years field trial period was ranged of 48.5% to 100.0%. No visual alfalfa injured was determined by any rates during the experimental period, and consequently, none of the applied herbicides reduced first-harvest alfalfa yields. Alfalfa yield was markedly affected by herbicide efficacy in all experimental years, particularly in the second year, where yields of herbicide treatments were similar to that of the weed free control.

  14. Concerted modulation of alanine and glutamate metabolism in young Medicago truncatula seedlings under hypoxic stress.

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    Limami, Anis M; Glévarec, Gaëlle; Ricoult, Claudie; Cliquet, Jean-Bernard; Planchet, Elisabeth

    2008-01-01

    The modulation of primary nitrogen metabolism by hypoxic stress was studied in young Medicago truncatula seedlings. Hypoxic seedlings were characterized by the up-regulation of glutamate dehydrogenase 1 (GDH1) and mitochondrial alanine aminotransferase (mAlaAT), and down-regulation of glutamine synthetase 1b (GS1b), NADH-glutamate synthase (NADH-GOGAT), glutamate dehydrogenase 3 (GDH3), and isocitrate dehydrogenase (ICDH) gene expression. Hypoxic stress severely inhibited GS activity and stimulated NADH-GOGAT activity. GDH activity was lower in hypoxic seedlings than in the control, however, under either normoxia or hypoxia, the in vivo activity was directed towards glutamate deamination. (15)NH(4) labelling showed for the first time that the adaptive reaction of the plant to hypoxia consisted of a concerted modulation of nitrogen flux through the pathways of both alanine and glutamate synthesis. In hypoxic seedlings, newly synthesized (15)N-alanine increased and accumulated as the major amino acid, asparagine synthesis was inhibited, while (15)N-glutamate was synthesized at a similar rate to that in the control. A discrepancy between the up-regulation of GDH1 expression and the down-regulation of GDH activity by hypoxic stress highlighted for the first time the complex regulation of this enzyme by hypoxia. Higher rates of glycolysis and ethanol fermentation are known to cause the fast depletion of sugar stores and carbon stress. It is proposed that the expression of GDH1 was stimulated by hypoxia-induced carbon stress, while the enzyme protein might be involved during post-hypoxic stress contributing to the regeneration of 2-oxoglutarate via the GDH shunt.

  15. Medicago truncatula symbiotic peptide NCR247 contributes to bacteroid differentiation through multiple mechanisms.

    Science.gov (United States)

    Farkas, Attila; Maróti, Gergely; Durgő, Hajnalka; Györgypál, Zoltán; Lima, Rui M; Medzihradszky, Katalin F; Kereszt, Attila; Mergaert, Peter; Kondorosi, Éva

    2014-04-08

    Symbiosis between rhizobia soil bacteria and legume plants results in the formation of root nodules where plant cells are fully packed with nitrogen fixing bacteria. In the host cells, the bacteria adapt to the intracellular environment and gain the ability for nitrogen fixation. Depending on the host plants, the symbiotic fate of bacteria can be either reversible or irreversible. In Medicago and related legume species, the bacteria undergo a host-directed multistep differentiation process culminating in the formation of elongated and branched polyploid bacteria with definitive loss of cell division ability. The plant factors are nodule-specific symbiotic peptides. Approximately 600 of them are nodule-specific cysteine-rich (NCR) peptides produced in the rhizobium-infected plant cells. NCRs are targeted to the endosymbionts, and concerted action of different sets of peptides governs different stages of endosymbiont maturation, whereas the symbiotic function of individual NCRs is unknown. This study focused on NCR247, a cationic peptide exhibiting in vitro antimicrobial activities. We show that NCR247 acts in those nodule cells where bacterial cell division is arrested and cell elongation begins. NCR247 penetrates the bacteria and forms complexes with many bacterial proteins. Interaction with FtsZ required for septum formation is one of the host interventions for inhibiting bacterial cell division. Complex formation with the ribosomal proteins affects translation and contributes to altered proteome and physiology of the endosymbiont. Binding to the chaperone GroEL amplifies the NCR247-modulated biological processes. We show that GroEL1 of Sinorhizobium meliloti is required for efficient infection, terminal differentiation, and nitrogen fixation.

  16. Speciation Matters: Bioavailability of Silver and Silver Sulfide Nanoparticles to Alfalfa (Medicago sativa).

    Science.gov (United States)

    Stegemeier, John P; Schwab, Fabienne; Colman, Benjamin P; Webb, Samuel M; Newville, Matthew; Lanzirotti, Antonio; Winkler, Christopher; Wiesner, Mark R; Lowry, Gregory V

    2015-07-21

    Terrestrial crops are directly exposed to silver nanoparticles (Ag-NPs) and their environmentally transformed analog silver sulfide nanoparticles (Ag2S-NPs) when wastewater treatment biosolids are applied as fertilizer to agricultural soils. This leads to a need to understand their bioavailability to plants. In the present study, the mechanisms of uptake and distribution of silver in alfalfa (Medicago sativa) were quantified and visualized upon hydroponic exposure to Ag-NPs, Ag2S-NPs, and AgNO3 at 3 mg total Ag/L. Total silver uptake was measured in dried roots and shoots, and the spatial distribution of elements was investigated using transmission electron microscopy (TEM) and synchrotron-based X-ray imaging techniques. Despite large differences in release of Ag(+) ions from the particles, Ag-NPs, Ag2S-NPs, and Ag(+) became associated with plant roots to a similar degree, and exhibited similarly limited (<1%) amounts of translocation of silver into the shoot system. X-ray fluorescence (XRF) mapping revealed differences in the distribution of Ag into roots for each treatment. Silver nanoparticles mainly accumulated in the (columella) border cells and elongation zone, whereas Ag(+) accumulated more uniformly throughout the root. In contrast, Ag2S-NPs remained largely adhered to the root exterior, and the presence of cytoplasmic nano-SixOy aggregates was observed. Exclusively in roots exposed to particulate silver, NPs smaller than the originally dosed NPs were identified by TEM in the cell walls. The apparent accumulation of Ag in the root apoplast determined by XRF, and the presence of small NPs in root cell walls suggests uptake of partially dissolved NPs and translocation along the apoplast.

  17. Complete nucleotide sequence of Alfalfa mosaic virus isolated from alfalfa (Medicago sativa L.) in Argentina.

    Science.gov (United States)

    Trucco, Verónica; de Breuil, Soledad; Bejerman, Nicolás; Lenardon, Sergio; Giolitti, Fabián

    2014-06-01

    The complete nucleotide sequence of an Alfalfa mosaic virus (AMV) isolate infecting alfalfa (Medicago sativa L.) in Argentina, AMV-Arg, was determined. The virus genome has the typical organization described for AMV, and comprises 3,643, 2,593, and 2,038 nucleotides for RNA1, 2 and 3, respectively. The whole genome sequence and each encoding region were compared with those of other four isolates that have been completely sequenced from China, Italy, Spain and USA. The nucleotide identity percentages ranged from 95.9 to 99.1 % for the three RNAs and from 93.7 to 99 % for the protein 1 (P1), protein 2 (P2), movement protein and coat protein (CP) encoding regions, whereas the amino acid identity percentages of these proteins ranged from 93.4 to 99.5 %, the lowest value corresponding to P2. CP sequences of AMV-Arg were compared with those of other 25 available isolates, and the phylogenetic analysis based on the CP gene was carried out. The highest percentage of nucleotide sequence identity of the CP gene was 98.3 % with a Chinese isolate and 98.6 % at the amino acid level with four isolates, two from Italy, one from Brazil and the remaining one from China. The phylogenetic analysis showed that AMV-Arg is closely related to subgroup I of AMV isolates. To our knowledge, this is the first report of a complete nucleotide sequence of AMV from South America and the first worldwide report of complete nucleotide sequence of AMV isolated from alfalfa as natural host.

  18. Genome-Wide Association Mapping and Genomic Selection for Alfalfa (Medicago sativa) Forage Quality Traits.

    Science.gov (United States)

    Biazzi, Elisa; Nazzicari, Nelson; Pecetti, Luciano; Brummer, E Charles; Palmonari, Alberto; Tava, Aldo; Annicchiarico, Paolo

    2017-01-01

    Genetic progress for forage quality has been poor in alfalfa (Medicago sativa L.), the most-grown forage legume worldwide. This study aimed at exploring opportunities for marker-assisted selection (MAS) and genomic selection of forage quality traits based on breeding values of parent plants. Some 154 genotypes from a broadly-based reference population were genotyped by genotyping-by-sequencing (GBS), and phenotyped for leaf-to-stem ratio, leaf and stem contents of protein, neutral detergent fiber (NDF) and acid detergent lignin (ADL), and leaf and stem NDF digestibility after 24 hours (NDFD), of their dense-planted half-sib progenies in three growing conditions (summer harvest, full irrigation; summer harvest, suspended irrigation; autumn harvest). Trait-marker analyses were performed on progeny values averaged over conditions, owing to modest germplasm × condition interaction. Genomic selection exploited 11,450 polymorphic SNP markers, whereas a subset of 8,494 M. truncatula-aligned markers were used for a genome-wide association study (GWAS). GWAS confirmed the polygenic control of quality traits and, in agreement with phenotypic correlations, indicated substantially different genetic control of a given trait in stems and leaves. It detected several SNPs in different annotated genes that were highly linked to stem protein content. Also, it identified a small genomic region on chromosome 8 with high concentration of annotated genes associated with leaf ADL, including one gene probably involved in the lignin pathway. Three genomic selection models, i.e., Ridge-regression BLUP, Bayes B and Bayesian Lasso, displayed similar prediction accuracy, whereas SVR-lin was less accurate. Accuracy values were moderate (0.3-0.4) for stem NDFD and leaf protein content, modest for leaf ADL and NDFD, and low to very low for the other traits. Along with previous results for the same germplasm set, this study indicates that GBS data can be exploited to improve both quality traits

  19. Salinity Adaptation and the Contribution of Parental Environmental Effects in Medicago truncatula.

    Science.gov (United States)

    Moriuchi, Ken S; Friesen, Maren L; Cordeiro, Matilde A; Badri, Mounawer; Vu, Wendy T; Main, Bradley J; Aouani, Mohamed Elarbi; Nuzhdin, Sergey V; Strauss, Sharon Y; von Wettberg, Eric J B

    2016-01-01

    High soil salinity negatively influences plant growth and yield. Some taxa have evolved mechanisms for avoiding or tolerating elevated soil salinity, which can be modulated by the environment experienced by parents or offspring. We tested the contribution of the parental and offspring environments on salinity adaptation and their potential underlying mechanisms. In a two-generation greenhouse experiment, we factorially manipulated salinity concentrations for genotypes of Medicago truncatula that were originally collected from natural populations that differed in soil salinity. To compare population level adaptation to soil salinity and to test the potential mechanisms involved we measured two aspects of plant performance, reproduction and vegetative biomass, and phenological and physiological traits associated with salinity avoidance and tolerance. Saline-origin populations had greater biomass and reproduction under saline conditions than non-saline populations, consistent with local adaptation to saline soils. Additionally, parental environmental exposure to salt increased this difference in performance. In terms of environmental effects on mechanisms of salinity adaptation, parental exposure to salt spurred phenological differences that facilitated salt avoidance, while offspring exposure to salt resulted in traits associated with greater salt tolerance. Non-saline origin populations expressed traits associated with greater growth in the absence of salt while, for saline adapted populations, the ability to maintain greater performance in saline environments was also associated with lower growth potential in the absence of salt. Plastic responses induced by parental and offspring environments in phenology, leaf traits, and gas exchange contribute to salinity adaptation in M. truncatula. The ability of plants to tolerate environmental stress, such as high soil salinity, is likely modulated by a combination of parental effects and within-generation phenotypic

  20. Interplay of Pathogen-Induced Defense Responses and Symbiotic Establishment in Medicago truncatula

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    Tao Chen

    2017-05-01

    Full Text Available Suppression of host innate immunity appears to be required for the establishment of symbiosis between rhizobia and host plants. In this study, we established a system that included a host plant, a bacterial pathogen and a symbiotic rhizobium to study the role of innate immunity during symbiotic interactions. A pathogenic bacterium, Pseudomonas syringae pv. tomato strain DC3000 (Pst DC3000, was shown to cause chlorosis in Medicago truncatula A17. Sinorhizobium meliloti strain Sm2011 (Sm2011 and Pst DC3000 strain alone induced similar defense responses in M. truncatula. However, when co-inoculated, Sm2011 specifically suppressed the defense responses induced by Pst DC3000, such as MAPK activation and ROS production. Inoculation with Sm2011 suppressed the transcription of defense-related genes triggered by Pst DC3000 infection, including the receptor of bacterial flagellin (FLS2, pathogenesis-related protein 10 (PR10, and the transcription factor WRKY33. Interestingly, inoculation with Pst DC3000 specifically inhibited the expression of the symbiosis marker genes nodule inception and nodulation pectate lyase and reduced the numbers of infection threads and nodules on M. truncatula A17 roots, indicating that Pst DC3000 inhibits the establishment of symbiosis in M. truncatula. In addition, defense-related genes, such as MAPK3/6, RbohC, and WRKY33, exhibited a transient increase in their expression in the early stage of symbiosis with Sm2011, but the expression dropped down to normal levels at later symbiotic stages. Our results suggest that plant innate immunity plays an antagonistic role in symbiosis by directly reducing the numbers of infection threads and nodules.

  1. Interplay of Pathogen-Induced Defense Responses and Symbiotic Establishment in Medicago truncatula.

    Science.gov (United States)

    Chen, Tao; Duan, Liujian; Zhou, Bo; Yu, Haixiang; Zhu, Hui; Cao, Yangrong; Zhang, Zhongming

    2017-01-01

    Suppression of host innate immunity appears to be required for the establishment of symbiosis between rhizobia and host plants. In this study, we established a system that included a host plant, a bacterial pathogen and a symbiotic rhizobium to study the role of innate immunity during symbiotic interactions. A pathogenic bacterium, Pseudomonas syringae pv. tomato strain DC3000 (Pst DC3000), was shown to cause chlorosis in Medicago truncatula A17. Sinorhizobium meliloti strain Sm2011 (Sm2011) and Pst DC3000 strain alone induced similar defense responses in M. truncatula. However, when co-inoculated, Sm2011 specifically suppressed the defense responses induced by Pst DC3000, such as MAPK activation and ROS production. Inoculation with Sm2011 suppressed the transcription of defense-related genes triggered by Pst DC3000 infection, including the receptor of bacterial flagellin (FLS2), pathogenesis-related protein 10 (PR10), and the transcription factor WRKY33. Interestingly, inoculation with Pst DC3000 specifically inhibited the expression of the symbiosis marker genes nodule inception and nodulation pectate lyase and reduced the numbers of infection threads and nodules on M. truncatula A17 roots, indicating that Pst DC3000 inhibits the establishment of symbiosis in M. truncatula. In addition, defense-related genes, such as MAPK3/6, RbohC, and WRKY33, exhibited a transient increase in their expression in the early stage of symbiosis with Sm2011, but the expression dropped down to normal levels at later symbiotic stages. Our results suggest that plant innate immunity plays an antagonistic role in symbiosis by directly reducing the numbers of infection threads and nodules.

  2. Screening of Cd tolerant genotypes and isolation of metallothionein genes in alfalfa (Medicago sativa L.)

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    Wang Xiaojuan, E-mail: xiaojuanwang@lzu.edu.cn [School of Pastoral Agriculture Science and Technology, Lanzhou University, P.O. Box 61, Lanzhou 730020 (China); Song, Yu [School of Pastoral Agriculture Science and Technology, Lanzhou University, P.O. Box 61, Lanzhou 730020 (China); Environment Management College of China, Qinhuangdao 066004 (China); Ma Yanhua [Hebei Normal University of Science and Technology, Qinhuangdao 066004 (China); Zhuo Renying [Key Lab of Tree Genomics, Research Institute of Subtropical of Forest, Chinese Academy of Forest, Fuyang 311400 (China); Jin Liang [School of Pastoral Agriculture Science and Technology, Lanzhou University, P.O. Box 61, Lanzhou 730020 (China)

    2011-12-15

    In order to evaluate Cd tolerance in wide-ranging sources of alfalfa (Medicago sativa) and to identify Cd tolerant genotypes which may potentially be useful for restoring Cd-contaminated environments, thirty-six accessions of alfalfa were screened under hydroponic culture. Our results showed that the relative root growth rate varied from 0.48 to 1.0, which indicated that different alfalfa accessions had various responses to Cd stress. The candidate fragments derived from differentially expressed metallothionein (MT) genes were cloned from leaves of two Cd tolerant genotypes, YE and LZ. DNA sequence and the deduced protein sequence showed that MsMT2a and MsMT2b had high similarity to those in leguminous plants. DDRT-PCR analysis showed that MsMT2a expressed in both YE and LZ plants under control and Cd stress treatment, but MsMT2b only expressed under Cd stress treatment. This suggested that MsMT2a was universally expressed in leaves of alfalfa but expression of MsMT2b was Cadmium (Cd) inducible. - Highlights: > Evaluate Cd tolerance in wide sources of alfalfa accessions. > Identify Cd-hyperaccumulators potentially useful for restoring Cd-contaminated environments. > Cloned differentially expressed metallothionein (MT) genes. > Characteristics and deduced protein sequence of MsMT2a and MsMT2b were analyzed. > MsMT2a might be a universally gene of alfalfa but MsMT2b might be an inductive gene. - Two Cd tolerant alfalfa genotypes were screened and their metallothionein genes were cloned which showed that MsMT2a was universally expressed but MsMT2b was Cd inducible expression.

  3. The alternative Medicago truncatula defense proteome of ROS – defective transgenic roots during early microbial infection

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    Leonard Muriithi Kiirika

    2014-07-01

    Full Text Available ROP-type GTPases of plants function as molecular switches within elementary signal transduction pathways such as the regulation of ROS synthesis via activation of NADPH oxidases (RBOH-respiratory burst oxidase homologue in plants. Previously, we reported that silencing of the Medicago truncatula GTPase MtROP9 led to reduced ROS production and suppressed induction of ROS-related enzymes in transgenic roots (MtROP9i infected with pathogenic (Aphanomyces euteiches and symbiotic microorganisms (Glomus intraradices, Sinorhizobium meliloti. While fungal infections were enhanced, S. meliloti infection was drastically impaired. In this study, we investigate the temporal proteome response of M. truncatula MtROP9i transgenic roots during the same microbial interactions under conditions of deprived potential to synthesize ROS. In comparison with control roots (Mtvector, we present a comprehensive proteomic analysis using sensitive MS protein identification. For four early infection time-points (1, 3, 5, 24 hpi, 733 spots were found to be different in abundance: 213 spots comprising 984 proteins (607 unique were identified after S. meliloti infection, 230 spots comprising 796 proteins (580 unique after G. intraradices infection, and 290 spots comprising 1240 proteins (828 unique after A. euteiches infection. Data evaluation by GelMap in combination with a heatmap tool allowed recognition of key proteome changes during microbial interactions under conditions of hampered ROS synthesis. Overall, the number of induced proteins in MtROP9i was low as compared with controls, indicating a dual function of ROS in defense signaling as well as alternative response patterns activated during microbial infection. Qualitative analysis of induced proteins showed that enzymes linked to ROS production and scavenging were highly induced in control roots, while in MtROP9i the majority of proteins were involved in alternative defense pathways such as cell wall and protein

  4. Cross-family translational genomics of abiotic stress-responsive genes between Arabidopsis and Medicago truncatula.

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    Daejin Hyung

    Full Text Available Cross-species translation of genomic information may play a pivotal role in applying biological knowledge gained from relatively simple model system to other less studied, but related, genomes. The information of abiotic stress (ABS-responsive genes in Arabidopsis was identified and translated into the legume model system, Medicago truncatula. Various data resources, such as TAIR/AtGI DB, expression profiles and literatures, were used to build a genome-wide list of ABS genes. tBlastX/BlastP similarity search tools and manual inspection of alignments were used to identify orthologous genes between the two genomes. A total of 1,377 genes were finally collected and classified into 18 functional criteria of gene ontology (GO. The data analysis according to the expression cues showed that there was substantial level of interaction among three major types (i.e., drought, salinity and cold stress of abiotic stresses. In an attempt to translate the ABS genes between these two species, genomic locations for each gene were mapped using an in-house-developed comparative analysis platform. The comparative analysis revealed that fragmental colinearity, represented by only 37 synteny blocks, existed between Arabidopsis and M. truncatula. Based on the combination of E-value and alignment remarks, estimated translation rate was 60.2% for this cross-family translation. As a prelude of the functional comparative genomic approaches, in-silico gene network/interactome analyses were conducted to predict key components in the ABS responses, and one of the sub-networks was integrated with corresponding comparative map. The results demonstrated that core members of the sub-network were well aligned with previously reported ABS regulatory networks. Taken together, the results indicate that network-based integrative approaches of comparative and functional genomics are important to interpret and translate genomic information for complex traits such as abiotic stresses.

  5. Differential expression proteomics to investigate responses and resistance to Orobanche crenata in Medicago truncatula

    Directory of Open Access Journals (Sweden)

    Diego Rubiales

    2009-07-01

    Full Text Available Abstract Background Parasitic angiosperm Orobanche crenata infection represents a major constraint for the cultivation of legumes worldwide. The level of protection achieved to date is either incomplete or ephemeral. Hence, an efficient control of the parasite requires a better understanding of its interaction and associated resistance mechanisms at molecular levels. Results In order to study the plant response to this parasitic plant and the molecular basis of the resistance we have used a proteomic approach. The root proteome of two accessions of the model legume Medicago truncatula displaying differences in their resistance phenotype, in control as well as in inoculated plants, over two time points (21 and 25 days post infection, has been compared. We report quantitative as well as qualitative differences in the 2-DE maps between early- (SA 27774 and late-resistant (SA 4087 genotypes after Coomassie and silver-staining: 69 differential spots were observed between non-inoculated genotypes, and 42 and 25 spots for SA 4087 and SA 27774 non-inoculated and inoculated plants, respectively. In all, 49 differential spots were identified by peptide mass fingerprinting (PMF following MALDI-TOF/TOF mass spectrometry. Many of the proteins showing significant differences between genotypes and after parasitic infection belong to the functional category of defense and stress-related proteins. A number of spots correspond to proteins with the same function, and might represent members of a multigenic family or post-transcriptional forms of the same protein. Conclusion The results obtained suggest the existence of a generic defense mechanism operating during the early stages of infection and differing in both genotypes. The faster response to the infection observed in the SA 27774 genotype might be due to the action of proteins targeted against key elements needed for the parasite's successful infection, such as protease inhibitors. Our data are discussed and

  6. Physiological and antioxidant responses of Medicago sativa-rhizobia symbiosis to cyanobacterial toxins (Microcystins) exposure.

    Science.gov (United States)

    El Khalloufi, Fatima; Oufdou, Khalid; Lahrouni, Majida; Faghire, Mustapha; Peix, Alvaro; Ramírez-Bahena, Martha Helena; Vasconcelos, Vitor; Oudra, Brahim

    2013-12-15

    Toxic cyanobacteria in freshwaters can induce potent harmful effects on growth and development of plants irrigated with contaminated water. In this study, the effect of cyanobacteria extract containing Microcystins (MC) on Medicago sativa-rhizobia symbiosis was investigated in order to explore plants response through biomass production, photosynthetic pigment and antioxidant enzymes analysis: Peroxidase (POD), Polyphenoloxidase (PPO) and Catalase (CAT). Alfalfa plants were inoculated with two endosymbiotic rhizobial strains: RhOL1 (MC less sensitive strain) and RhOL3 (MC more sensitive strain), to evaluate the rhizobial contribution on the plant response cultured under cyanobacterial toxins stress. The two rhizobia strains were identified as Ensifer meliloti by sequence analysis of their rrs and atpD genes. The chronic exposure to MC extract showed shoot, root and nodules dry weight decrease, in both symbiosis cultures. The rate of decline in plants inoculated with RhOL3 was higher than that in symbiosis with RhOL1 mainly at 20 μg L(-1) of MC. Cyanotoxins also reduced photosynthetic pigment content and generated an oxidative stress observed at cellular level. POD, PPO and CAT activities were significantly increased in leaves, roots and nodules of alfalfa plants exposed to MC. These enzyme activities were higher in plants inoculated with RhOL3 especially when alfalfa plants were exposed to 20 μg L(-1) of MC. The present paper reports new scientific finding related to the behavior of rhizobia-M. sativa associations to MC (Microcystins) for later recommendation concerning the possible use of these symbiosis face to crops exposure to MC contaminated water irrigation.

  7. Integrated metabolomics and transcriptomics reveal enhanced specialized metabolism in Medicago truncatula root border cells.

    Science.gov (United States)

    Watson, Bonnie S; Bedair, Mohamed F; Urbanczyk-Wochniak, Ewa; Huhman, David V; Yang, Dong Sik; Allen, Stacy N; Li, Wensheng; Tang, Yuhong; Sumner, Lloyd W

    2015-04-01

    Integrated metabolomics and transcriptomics of Medicago truncatula seedling border cells and root tips revealed substantial metabolic differences between these distinct and spatially segregated root regions. Large differential increases in oxylipin-pathway lipoxygenases and auxin-responsive transcript levels in border cells corresponded to differences in phytohormone and volatile levels compared with adjacent root tips. Morphological examinations of border cells revealed the presence of significant starch deposits that serve as critical energy and carbon reserves, as documented through increased β-amylase transcript levels and associated starch hydrolysis metabolites. A substantial proportion of primary metabolism transcripts were decreased in border cells, while many flavonoid- and triterpenoid-related metabolite and transcript levels were increased dramatically. The cumulative data provide compounding evidence that primary and secondary metabolism are differentially programmed in border cells relative to root tips. Metabolic resources normally destined for growth and development are redirected toward elevated accumulation of specialized metabolites in border cells, resulting in constitutively elevated defense and signaling compounds needed to protect the delicate root cap and signal motile rhizobia required for symbiotic nitrogen fixation. Elevated levels of 7,4'-dihydroxyflavone were further increased in border cells of roots exposed to cotton root rot (Phymatotrichopsis omnivora), and the value of 7,4'-dihydroxyflavone as an antimicrobial compound was demonstrated using in vitro growth inhibition assays. The cumulative and pathway-specific data provide key insights into the metabolic programming of border cells that strongly implicate a more prominent mechanistic role for border cells in plant-microbe signaling, defense, and interactions than envisioned previously.

  8. Influence of pCO2 on carbon allocation in nodulated Medicago sativa L.

    Science.gov (United States)

    Pereyra, Gabriela; Hartmann, Henrik; Ziegler, Waldemar; Michalzik, Beate; Gonzalez-Meler, Miquel; Trumbore, Susan

    2016-04-01

    Atmospheric CO2 concentrations (pCO_2) have been related to changes in plant carbon (C) availability and photosynthetic capacity, yet there is no clear consensus as to the effect of pCO2 on the plant C balance and on nitrogen fixation in symbiotic systems. We investigated how different pCO2 (Pleistocene: 170 ppm, ambient: 400 ppm and projected future: 700 ppm) influence C allocation in nodulated Medicago sativa L. We labeled 17 week old plants with depleted 13C (-34.7±1.2‰) and traced the label over a 9-day period, to assess the redistribution of newly assimilated C across different sinks, including nodules. We analyzed N concentrations in plant tissues and found no significant differences in leaves and roots across treatments. However, growth and C fixation rates increased with pCO_2, and differences were greatest between 170 ppm and 700 ppm. Across pCO2 treatments we observed a 13C-enrichment in roots compared to leaves. We further observed the highest 13C depletion of non-structural carbohydrates (NSCs) and respired CO2 in tissues of plants grown at 700 ppm, especially in leaves and nodules. Our preliminary results suggest that sink organs like roots and nodules are fed with newly-assimilated NSCs from leaves to support respiration, and especially in 170 ppm plants represented a major respiratory loss of newly assimilated C (≈ 35{%} of the total plant respiration). Our results suggest that although plant metabolic processes like photosynthesis and respiration are affected by changes in pCO_2, nitrogen acquisition in such a symbiotic system is not.

  9. Biogenic Pt uptake and nanoparticle formation in Medicago sativa and Brassica juncea

    Science.gov (United States)

    Bali, Roza; Siegele, Rainer; Harris, Andrew T.

    2010-10-01

    The ability of the facultative metallophyte plants, Medicago sativa ( M. sativa) and Brassica juncea ( B. juncea) to accumulate and translocate platinum (Pt) from aqueous substrates is reported. The influence of Pt concentration in the substrate (5, 10, 20, 40 and 80 ppm), exposure time (24, 48 and 72 h) and substrate pH (2, 3, 5, 7 and 9) was determined. In both plants the concentration of Pt increased with substrate concentration and exposure time. Greater accumulation was detected in the roots of M. sativa than B. juncea, up to a maximum of 94.19 mg Pt g-1 (dry biomass) compared with 38.5 mg Pt g-1 (dry biomass) following exposure to 80 ppm Pt after 72 h exposure, respectively. However, at lower substrate concentrations (5 and 20 ppm) greater quantities of Pt were detected in the shoots of B. juncea, ranging between 0.02 and 0.32 mg Pt g-1 (dry biomass) at 5 ppm across the different time intervals studied, compared with 0.02-0.14 mg Pt g-1 (dry biomass) for M. sativa, suggesting B. juncea to be a better translocator of Pt under idealised conditions at low concentrations. Higher Pt uptake was also observed in acidic media, with a maximum at pH 2 for M. sativa and pH 3 for B. juncea, indicating the role of net surface charge on the bioaccumulation of Pt. Once sequestered Pt(II) was reduced to Pt(0) due to the action of local metabolites. TEM images of M. sativa root samples showed the in vivo formation of Pt nanoparticles between 3 and 100 nm in size and of varying morphologies in the epidermal root cells. In vivo Pt distribution profiles were assessed using proton induced X-ray emission (μ-PIXE) spectroscopy, which showed even distribution across all tissue systems (epidermal, cortical and vascular) within the roots of both M. sativa and B. juncea.

  10. The coupling of the plant and microbial catabolisms of phenanthrene in the rhizosphere of Medicago sativa.

    Science.gov (United States)

    Muratova, Anna; Dubrovskaya, Ekaterina; Golubev, Sergey; Grinev, Vyacheslav; Chernyshova, Marina; Turkovskaya, Olga

    2015-09-01

    We studied the catabolism of the polycyclic aromatic hydrocarbon phenanthrene by four rhizobacterial strains and the possibility of enzymatic oxidation of this compound and its microbial metabolites by the root exudates of alfalfa (Medicago sativa L.) in order to detect the possible coupling of the plant and microbial metabolisms under the rhizospheric degradation of the organic pollutant. A comparative study of phenanthrene degradation pathways in the PAH-degrading rhizobacteria Ensifer meliloti, Pseudomonas kunmingensis, Rhizobium petrolearium, and Stenotrophomonas sp. allowed us to identify the key metabolites from the microbial transformation of phenanthrene, including 9,10-phenanthrenequinone, 2-carboxybenzaldehyde, and 1-hydroxy-2-naphthoic, salicylic, and o-phthalic acids. Sterile alfalfa plants were grown in the presence and absence of phenanthrene (0.03 g kg(-1)) in quartz sand under controlled environmental conditions to obtain plant root exudates. The root exudates were collected, concentrated by ultrafiltration, and the activity of oxidoreductases was detected spectrophotometrically by the oxidation rate for various substrates. The most marked activity was that of peroxidase, whereas the presence of oxidase and tyrosinase was detected on the verge of the assay sensitivity. Using alfalfa root exudates as a crude enzyme preparation, we found that in the presence of the synthetic mediator, the plant peroxidase could oxidize phenanthrene and its microbial metabolites. The results indicate the possibility of active participation of plants in the rhizospheric degradation of polycyclic aromatic hydrocarbons and their microbial metabolites, which makes it possible to speak about the coupling of the plant and microbial catabolisms of these contaminants in the rhizosphere.

  11. Exogenous Hematin Alleviates Mercury-induced Oxidative Damage in the Roots of Medicago sativa

    Institute of Scientific and Technical Information of China (English)

    Yi Han; Wei Xuan; Tian Yu; Wen-Bing Fang; Tian-Ling Lou; Yin Gao; Xiao-Yue Chen; Xiao Xiao; Wen-Biao Shen

    2007-01-01

    In the present study, we evaluated the protective effect of exogenous heme oxygenase-1 (HO-1 EC1.14.99.3) inducer hematin against mercury-induced oxidative damage in the roots of Alfalfa (Medicago sativa L.).Plants exposed to mercury (HgCl2) exhibited a significant increase of lipid peroxidation, as well as inhibition of root elongation.However, hematin (50 μM)supplementation to HgCl2 (100 μmol/L) treated plants effectively reduced the lipid peroxidation and partially increased the root elongation.These responses were mimicked by the application of aqueous solution of carbon monoxide (CO) with 50% saturation.Also, treatment with hematin could result in the potent induction of HO-1 transcript in the root tissues,as detected 12h following treatment.Moreover, the activation of anti-oxidant enzyme, including glutathione reductase,monodehydroascorbate reductase and superoxide dismutase activities, and the decrease of lipoxygenase activity, were induced by hematin at 12h or 24h, which was further confirmed by histochemical staining for the detection of lipid peroxidation and loss of membrane integrity.Whereas, ascorbate peroxidase and guaiacol peroxidase isozyme activities or their transcripts were reduced, respectively, indicating that hydrogen peroxide might act as a signal to mediate Hg-tolerance at the beginning of treatment.The ameliorating effects of hematin were specific, since the CO scavenger hemoglobin differentially reversed the above actions.Taken together, our results suggested that hematin exhibits a vital role in protecting the plant against Hg-induced oxidative damage.

  12. Salinity Adaptation and the Contribution of Parental Environmental Effects in Medicago truncatula.

    Directory of Open Access Journals (Sweden)

    Ken S Moriuchi

    Full Text Available High soil salinity negatively influences plant growth and yield. Some taxa have evolved mechanisms for avoiding or tolerating elevated soil salinity, which can be modulated by the environment experienced by parents or offspring. We tested the contribution of the parental and offspring environments on salinity adaptation and their potential underlying mechanisms. In a two-generation greenhouse experiment, we factorially manipulated salinity concentrations for genotypes of Medicago truncatula that were originally collected from natural populations that differed in soil salinity. To compare population level adaptation to soil salinity and to test the potential mechanisms involved we measured two aspects of plant performance, reproduction and vegetative biomass, and phenological and physiological traits associated with salinity avoidance and tolerance. Saline-origin populations had greater biomass and reproduction under saline conditions than non-saline populations, consistent with local adaptation to saline soils. Additionally, parental environmental exposure to salt increased this difference in performance. In terms of environmental effects on mechanisms of salinity adaptation, parental exposure to salt spurred phenological differences that facilitated salt avoidance, while offspring exposure to salt resulted in traits associated with greater salt tolerance. Non-saline origin populations expressed traits associated with greater growth in the absence of salt while, for saline adapted populations, the ability to maintain greater performance in saline environments was also associated with lower growth potential in the absence of salt. Plastic responses induced by parental and offspring environments in phenology, leaf traits, and gas exchange contribute to salinity adaptation in M. truncatula. The ability of plants to tolerate environmental stress, such as high soil salinity, is likely modulated by a combination of parental effects and within

  13. Crosstalk between the nodulation signaling pathway and the autoregulation of nodulation in Medicago truncatula.

    Science.gov (United States)

    Saur, Isabel M L; Oakes, Marie; Djordjevic, Michael A; Imin, Nijat

    2011-06-01

    A subset of CLAVATA3/endosperm-surrounding region-related (CLE) peptides are involved in autoregulation of nodulation (AON) in Medicago truncatula (e.g. MtCLE12 and MtCLE13). However, their linkage to other components of the AON pathways downstream of the shoot-derived inhibitor (SDI) is not understood. We have ectopically expressed the putative peptide ligand encoding genes MtCLE12 and MtCLE13 in M. truncatula which abolished nodulation completely in wild-type roots but not in the supernodulating null mutant sunn-4. Further, root growth inhibition was detected when MtCLE12 was ectopically expressed in wild-type roots or synthetic CLE12 peptide was applied exogenously. To identify downstream genes, roots of wild-type and sunn-4 mutant overexpressing MtCLE12 were used for quantitative gene expression analysis. We found that, in 35S:MtCLE12 roots, NODULE INCEPTION (NIN, a central regulator of nodulation) was down-regulated, whereas MtEFD (ethylene response factor required for nodule differentiation) and MtRR8 (a type-A response regulator thought to be involved in the negative regulation of cytokinin signaling), were up-regulated. Moreover, we found that the up-regulation of MtEFD and MtRR8 caused by overexpressing MtCLE12 is SUNN-dependent. Hence, our data link for the first time the pathways for Nod factor signaling, cytokinin perception and AON. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.

  14. CLE Peptides Control Medicago truncatula Nodulation Locally and Systemically1[C][W][OA

    Science.gov (United States)

    Mortier, Virginie; Den Herder, Griet; Whitford, Ryan; Van de Velde, Willem; Rombauts, Stephane; D'haeseleer, Katrien; Holsters, Marcelle; Goormachtig, Sofie

    2010-01-01

    The CLAVATA3/embryo-surrounding region (CLE) peptides control the fine balance between proliferation and differentiation in plant development. We studied the role of CLE peptides during indeterminate nodule development and identified 25 MtCLE peptide genes in the Medicago truncatula genome, of which two genes, MtCLE12 and MtCLE13, had nodulation-related expression patterns that were linked to proliferation and differentiation. MtCLE13 expression was up-regulated early in nodule development. A high-to-low expression gradient radiated from the inner toward the outer cortical cell layers in a region defining the incipient nodule. At later stages, MtCLE12 and MtCLE13 were expressed in differentiating nodules and in the apical part of mature, elongated nodules. Functional analysis revealed a putative role for MtCLE12 and MtCLE13 in autoregulation of nodulation, a mechanism that controls the number of nodules and involves systemic signals mediated by a leucine-rich repeat receptor-like kinase, SUNN, which is active in the shoot. When MtCLE12 and MtCLE13 were ectopically expressed in transgenic roots, nodulation was abolished at the level of the nodulation factor signal transduction, and this inhibition involved long-distance signaling. In addition, composite plants with roots ectopically expressing MtCLE12 or MtCLE13 had elongated petioles. This systemic effect was not observed in transgenic roots ectopically expressing MtCLE12 and MtCLE13 in a sunn-1 mutant background, although nodulation was still strongly reduced. These results suggest multiple roles for CLE signaling in nodulation. PMID:20348212

  15. Flavones and flavonols play distinct critical roles during nodulation of Medicago truncatula by Sinorhizobium meliloti.

    Science.gov (United States)

    Zhang, Juan; Subramanian, Senthil; Stacey, Gary; Yu, Oliver

    2009-01-01

    Flavonoids play critical roles in legume-rhizobium symbiosis. However, the role of individual flavonoid compounds in this process has not yet been clearly established. We silenced different flavonoid-biosynthesis enzymes to generate transgenic Medicago truncatula roots with different flavonoid profiles. Silencing of chalcone synthase, the key entry-point enzyme for flavonoid biosynthesis led to flavonoid-deficient roots. Silencing of isoflavone synthase and flavone synthase led to roots deficient for a subset of flavonoids, isoflavonoids (formononetin and biochanin A) and flavones (7,4'-dihydroxyflavone), respectively. When tested for nodulation by Sinorhizobium meliloti, flavonoid-deficient roots had a near complete loss of nodulation, whereas flavone-deficient roots had reduced nodulation. Isoflavone-deficient roots nodulated normally, suggesting that isoflavones might not play a critical role in M. truncatula nodulation, even though they are the most abundant root flavonoids. Supplementation of flavone-deficient roots with 7, 4'-dihydroxyflavone, a major inducer of S. meliloti nod genes, completely restored nodulation. However, the same treatment did not restore nodulation in flavonoid-deficient roots, suggesting that other non-nod gene-inducing flavonoid compounds are also critical to nodulation. Supplementation of roots with the flavonol kaempferol (an inhibitor of auxin transport), in combination with the use of flavone pre-treated S. meliloti cells, completely restored nodulation in flavonoid-deficient roots. In addition, S. meliloti cells constitutively producing Nod factors were able to nodulate flavone-deficient roots, but not flavonoid-deficient roots. These observations indicated that flavones might act as internal inducers of rhizobial nod genes, and that flavonols might act as auxin transport regulators during nodulation. Both these roles of flavonoids appear critical for symbiosis in M. truncatula.

  16. Exploring the nuclear proteome of Medicago truncatula at the switch towards seed filling.

    Science.gov (United States)

    Repetto, Ombretta; Rogniaux, Hélène; Firnhaber, Christian; Zuber, Hélène; Küster, Helge; Larré, Colette; Thompson, Richard; Gallardo, Karine

    2008-11-01

    Despite its importance in determining seed composition, and hence quality, regulation of the development of legume seeds is incompletely understood. Because of the cardinal role played by the nucleus in gene expression and regulation, we have characterized the nuclear proteome of Medicago truncatula at the 12 days after pollination (dap) stage that marks the switch towards seed filling. Nano-liquid chromatography-tandem mass spectrometry analysis of nuclear protein bands excised from one-dimensional SDS-PAGE identified 179 polypeptides (143 different proteins), providing an insight into the complexity and distinctive feature of the seed nuclear proteome and highlighting new plant nuclear proteins with possible roles in the biogenesis of ribosomal subunits (PESCADILLO-like) or nucleocytoplasmic trafficking (dynamin-like GTPase). The results revealed that nuclei of 12-dap seeds store a pool of ribosomal proteins in preparation for intense protein synthesis activity, occurring subsequently during seed filling. Diverse proteins of the molecular machinery leading to the synthesis of ribosomal subunits were identified along with proteins involved in transcriptional regulation, RNA processing or transport. Some had already been shown to play a role during the early stages of seed formation whereas for others the findings are novel (e.g. the DIP2 and ES43 transcriptional regulators or the RNA silencing-related ARGONAUTE proteins). This study also revealed the presence of chromatin-modifying enzymes and RNA interference proteins that have roles in RNA-directed DNA methylation and may be involved in modifying genome architecture and accessibility during seed filling and maturation.

  17. Proteomic identification of differentially expressed proteins during alfalfa (Medicago sativa L. flower development

    Directory of Open Access Journals (Sweden)

    Lingling Chen

    2016-10-01

    Full Text Available Flower development, pollination, and fertilization are important stages in the sexual reproduction process of plants; they are also critical steps in the control of seed formation and development. During alfalfa (Medicago sativa L. seed production, some distinct phenomena such as a low seed setting ratio, serious flower falling, and seed abortion commonly occur. However, the causes of these phenomena are complicated and largely unknown. An understanding of the mechanisms that regulate alfalfa flowering is important in order to increase seed yield. Hence, proteomic technology was used to analyze changes in protein expression during the stages of alfalfa flower development. Flower samples were collected at pre-pollination (S1, pollination (S2, and the post-pollination senescence period (S3. Twenty-four differentially expressed proteins were successfully identified, including 17 down-regulated in pollinated flowers, one up-regulated in pollinated and senesced flowers, and six up-regulated in senesced flowers. The largest proportions of the identified proteins were involved in metabolism, signal transduction, defense response, oxidation reduction, cell death, and programmed cell death (PCD. Their expression profiles demonstrated that energy metabolism, carbohydrate metabolism, and amino acid metabolism provided the nutrient foundation for pollination in alfalfa. Furthermore, there were three proteins involved in multiple metabolic pathways: dual specificity kinase splA-like protein (kinase splALs, carbonic anhydrase (CA, and NADPH: quinone oxidoreductase-like protein (NQOLs. Expression patterns of these proteins indicated that MAPK cascades regulated multiple processes, such as signal transduction, stress response, and cell death. PCD also played an important role in the alfalfa flower developmental process, and regulated both pollination and flower senescence. The current study sheds some light on protein expression profiles during alfalfa flower

  18. The construction of genetic linkage frame map in tetraploid Medicago using RAPD markers%利用RAPD技术构建四倍体苜蓿遗传连锁图谱

    Institute of Scientific and Technical Information of China (English)

    刘曙娜; 于林清; 周延林; 吉仁花; 陈世茹; 孙娟娟; 么婷婷

    2012-01-01

    Using random amplified polymorphic DNA (RAPD) molecular genetic markers analyze the F2 population of 94 plant individuals. The F2 segregating population derived from a self-pollinated F1 hybrid individual of the cross Medicago sativa ×Medicago falcata. The genetic analyses were performed by using maximum-likelihood equations and related computer programs. The genetic map comprises 74 markers, and contains 8 linkage groups covering 1 261. 5 cM, with an average distance of 24. 73 cM between markers. This genetic linkage map provides an entry point for the construction of saturated tetraploid alfalfa molecular genetic map and further development of alfalfa molecular genetic research.%利用随机扩增DNA多态性分子遗传标记(RAPD)对F2群体进行分析.F2群体由F1群体(高产紫花苜蓿×高抗黄花苜蓿得到F1代)自交获得.应用MAPMAKER/EXP(3.0)与JionMap 4.0并结合MapDrawV 2.1软件构建四倍体苜蓿的遗传连锁图谱.从192个随机引物中筛选出72个引物,对94个F2个体及F1双亲DNA样本进行了RAPD扩增,共获得51个RAPD标记,构建了四倍体苜蓿分子遗传连锁框架图,其中包含8个连锁群,标记覆盖的基因组总长度约为1 261.5 cM,标记间平均距离为24.73 cM.本图谱为构建饱和的四倍体苜蓿分子遗传图谱提供了框架结构,为进一步开展苜蓿分子遗传方面的研究奠定了基础.

  19. Hybrid Gear

    Science.gov (United States)

    Handschuh, Robert F. (Inventor); Roberts, Gary D. (Inventor)

    2016-01-01

    A hybrid gear consisting of metallic outer rim with gear teeth and metallic hub in combination with a composite lay up between the shaft interface (hub) and gear tooth rim is described. The composite lay-up lightens the gear member while having similar torque carrying capability and it attenuates the impact loading driven noise/vibration that is typical in gear systems. The gear has the same operational capability with respect to shaft speed, torque, and temperature as an all-metallic gear as used in aerospace gear design.

  20. Hybrid Qualifications

    DEFF Research Database (Denmark)

    has turned out as a major focus of European education and training policies and certainly is a crucial principle underlying the European Qualifications Framework (EQF). In this context, «hybrid qualifications» (HQ) may be seen as an interesting approach to tackle these challenges as they serve «two...... masters», i.e. by producing skills for the labour market and enabling individuals to progress more or less directly to higher education. The specific focus of this book is placed on conditions, structures and processes which help to combine VET with qualifications leading into higher education...

  1. Chemical investigation of saponins from twelve annual Medicago species and their bioassay with the brine shrimp Artemia salina.

    Science.gov (United States)

    Tava, Aldo; Pecetti, Luciano

    2012-07-01

    The saponin and sapogenin composition of the aerial growth of 12 annual Medicago species sampled at full senescence were investigated. Saponins were extracted from the plant material and obtained in a highly pure grade by reverse-phase chromatography, with a yield ranging from 0.38 +/- 0.04% to 1.35 +/- 0.08% dry matter, depending on the species. Sapogenins were then obtained after acid hydrolysis of saponins, and evaluated by GC/FID and GC/MS methods. Different compositions of the aglycone moieties were observed in the 12 Medicago species. Medicagenic acid was the dominant aglycone in M. x blancheana, M. doliata, M. littoralis, M. rotata, M. rugosa, M. scutellata, M. tornata and M. truncatula, bayogenin and hederagenin in M. arabica and M. rigidula, echinocystic acid in M. polymorpha, and soyasapogenol B in M. aculeata. The purified saponin mixtures, characterized by different chemical compositions, were then used in a toxicity test using the brine shrimp Artemia salina. The most active compounds were the saponins from M. arabica and M. rigidula with LD50 values of 10.1 and 4.6 microg/mL, respectively. A structure-activity relationship for the tested saponin mixtures was observed.

  2. Molecular cloning and functional analysis of the drought tolerance gene MsHSP70 from alfalfa (Medicago sativa L.).

    Science.gov (United States)

    Li, Zhenyi; Long, Ruicai; Zhang, Tiejun; Wang, Zhen; Zhang, Fan; Yang, Qingchuan; Kang, Junmei; Sun, Yan

    2017-03-01

    Heat shock proteins (HSPs) are a ubiquitously expressed class of protective proteins that play a key role in plant response to stressful conditions. This study aimed to characterize and investigate the function of an HSP gene in alfalfa (Medicago sativa). MsHSP70, which contains a 2028-bp open reading frame, was identified through homology cloning. MsHSP70 shares high sequence identity (94.47%) with HSP70 from Medicago truncatula. Expression analysis of MsHSP70 in alfalfa organs revealed a relatively higher expression level in aerial organs such as flowers, stems and leaves than in roots. MsHSP70 was induced by heat shock, abscisic acid (ABA) and hydrogen peroxide. Transgenic Arabidopsis seedlings overexpressing MsHSP70 were hyposensitive to polyethylene glycol (PEG) and ABA treatments, suggesting that exogenous expression of MsHSP70 enhanced Arabidopsis tolerance to these stresses. Examination of physiological indexes related to drought and ABA stress demonstrated that in comparison with non-transgenic plants, T3 transgenic Arabidopsis plants had an increased proline content, higher superoxide dismutase (SOD) activity, and decreased malondialdehyde (MDA) content. Furthermore, higher relative water content (RWC) was detected in transgenic plants compared with non-transgenic plants under drought stress. These findings clearly indicate that molecular manipulation of MsHSP70 in plants can have substantial effects on stress tolerance.

  3. The lipopolysaccharide of Sinorhizobium meliloti suppresses defense-associated gene expression in cell cultures of the host plant Medicago truncatula.

    Science.gov (United States)

    Tellström, Verena; Usadel, Björn; Thimm, Oliver; Stitt, Mark; Küster, Helge; Niehaus, Karsten

    2007-02-01

    In the establishment of symbiosis between Medicago truncatula and the nitrogen-fixing bacterium Sinorhizobium meliloti, the lipopolysaccharide (LPS) of the microsymbiont plays an important role as a signal molecule. It has been shown in cell cultures that the LPS is able to suppress an elicitor-induced oxidative burst. To investigate the effect of S. meliloti LPS on defense-associated gene expression, a microarray experiment was performed. For evaluation of the M. truncatula microarray datasets, the software tool MapMan, which was initially developed for the visualization of Arabidopsis (Arabidopsis thaliana) datasets, was adapted by assigning Medicago genes to the ontology originally created for Arabidopsis. This allowed functional visualization of gene expression of M. truncatula suspension-cultured cells treated with invertase as an elicitor. A gene expression pattern characteristic of a defense response was observed. Concomitant treatment of M. truncatula suspension-cultured cells with invertase and S. meliloti LPS leads to a lower level of induction of defense-associated genes compared to induction rates in cells treated with invertase alone. This suppression of defense-associated transcriptional rearrangement affects genes induced as well as repressed by elicitation and acts on transcripts connected to virtually all kinds of cellular processes. This indicates that LPS of the symbiont not only suppresses fast defense responses as the oxidative burst, but also exerts long-term influences, including transcriptional adjustment to pathogen attack. These data indicate a role for LPS during infection of the plant by its symbiotic partner.

  4. Multifaceted Investigation of Metabolites During Nitrogen Fixation in Medicago via High Resolution MALDI-MS Imaging and ESI-MS

    Science.gov (United States)

    Gemperline, Erin; Jayaraman, Dhileepkumar; Maeda, Junko; Ané, Jean-Michel; Li, Lingjun

    2015-01-01

    Legumes have developed the unique ability to establish a symbiotic relationship with soil bacteria known as rhizobia. This interaction results in the formation of root nodules in which rhizobia thrive and reduce atmospheric dinitrogen into plant-usable ammonium through biological nitrogen fixation (BNF). Owing to the availability of genetic information for both of the symbiotic partners, the Medicago truncatula- Sinorhizobium meliloti association is an excellent model for examining the BNF process. Although metabolites are important in this symbiotic association, few studies have investigated the array of metabolites that influence this process. Of these studies, most target only a few specific metabolites, the roles of which are either well known or are part of a well-characterized metabolic pathway. Here, we used a multifaceted mass spectrometric (MS) approach to detect and identify the key metabolites that are present during BNF using the Medicago truncatula- Sinorhizobium meliloti association as the model system. High mass accuracy and high resolution matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI) Orbitrap instruments were used in this study and provide complementary results for more in-depth characterization of the nitrogen-fixation process. We used well-characterized plant and bacterial mutants to highlight differences between the metabolites that are present in functional versus nonfunctional nodules. Our study highlights the benefits of using a combination of mass spectrometric techniques to detect differences in metabolite composition and the distributions of these metabolites in plant biology.

  5. Analysis of Cell Wall-Related Genes in Organs of Medicago sativa L. under Different Abiotic Stresses.

    Science.gov (United States)

    Behr, Marc; Legay, Sylvain; Hausman, Jean-Francois; Guerriero, Gea

    2015-07-16

    Abiotic constraints are a source of concern in agriculture, because they can have a strong impact on plant growth and development, thereby affecting crop yield. The response of plants to abiotic constraints varies depending on the type of stress, on the species and on the organs. Although many studies have addressed different aspects of the plant response to abiotic stresses, only a handful has focused on the role of the cell wall. A targeted approach has been used here to study the expression of cell wall-related genes in different organs of alfalfa plants subjected for four days to three different abiotic stress treatments, namely salt, cold and heat stress. Genes involved in different steps of cell wall formation (cellulose biosynthesis, monolignol biosynthesis and polymerization) have been analyzed in different organs of Medicago sativa L. Prior to this analysis, an in silico classification of dirigent/dirigent-like proteins and class III peroxidases has been performed in Medicago truncatula and M. sativa. The final goal of this study is to infer and compare the expression patterns of cell wall-related genes in response to different abiotic stressors in the organs of an important legume crop.

  6. Enhanced nodulation and nodule development by nolR mutants of Sinorhizobium medicae on specific Medicago host genotypes.

    Science.gov (United States)

    Sugawara, Masayuki; Sadowsky, Michael J

    2014-04-01

    The nolR gene encodes a negatively acting, transcriptional regulatory protein of core Nod-factor biosynthetic genes in the sinorhizobia. Although previous reports showed that nolR modulates Nod-factor production and enhances nodulation speed of Sinorhizobium meliloti on alfalfa, there have been no reports for the symbiotic function of this gene in the S. medicae-Medicago truncatula symbiosis. Here, we constructed an nolR mutant of S. medicae WSM419 and evaluated mutant and wild-type strains for their nodulation ability, competitiveness, host specificity, and density-dependent nodulation phenotypes. When the mutant was inoculated at low and medium population densities, it showed enhanced nodule formation during the initial stages of nodulation. Results of quantitative competitive nodulation assays indicated that an nolR mutant had 2.3-fold greater competitiveness for nodulation on M. truncatula 'A17' than did the wild-type strain. Moreover, the nodulation phenotype of the nolR mutant differed among Medicago genotypes and showed significantly enhanced nodule development on M. tricycla. Taken together, these results indicated that mutation of nolR in S. medicae positively influenced nodule initiation, competitive nodulation, and nodule development at later nodulation stages. This may allow nolR mutants of S. medicae to have a selective advantage under field conditions.

  7. Stress tolerance and symbiotic and phylogenic features of root nodule bacteria associated with Medicago species in different bioclimatic regions of Tunisia.

    Science.gov (United States)

    Djedidi, Salem; Yokoyama, Tadashi; Ohkama-Ohtsu, Naoko; Risal, Chandra Prasad; Abdelly, Chedly; Sekimoto, Hitoshi

    2011-01-01

    Thirty two rhizobial isolates were obtained from different bioclimatic regions of Tunisia using as trap plants, Medicago sativa, Medicago ciliaris, Medicago polymorpha and Medicago minima. To study their diversity and characterize them in relation to Mediterranean conditions, abiotic stress resistance, symbiotic properties and genetic diversity in terms of 16S rRNA and nodA sequences were assessed. Five isolates from M. sativa, three from M. ciliaris and three from M. minima could grow at 45°C. Only two isolates from M. sativa grew at 4% NaCl. The most stress tolerant isolates were obtained from arid soils. A phylogenetic analysis of 16S rRNA genes revealed 29 isolates to be closely related to Ensifer including one (Pl.3-9) that showed a 16S rRNA sequence similar to that of Ensifer meliloti and nodA sequence similar to that of Ensifer medicae. However, three isolates were categorized into Agrobacterium containing the nodA of Ensifer. Furthermore, these isolates developed nodules on original hosts. The results for the four isolates suggest horizontal gene transfer between the species.

  8. How planting configuration influences plant secondary metabolites and total N in tall fescue (Festuca arundinacea Schreb.), alfalfa (Medicago sativa L.) and birdsfoot trefoil (Lotus corniculatus L.)

    Science.gov (United States)

    Theories suggest that incorporating alfalfa (Medicago sativa L.; Alf) or birdsfoot trefoil (Lotus corniculatus L.; BFT) into endophyte-infected tall fescue (Festuca arundinaceas Schreb.; E+TF) pasturelands may improve livestock production. We investigated how planting configuration might influence p...

  9. Role of N-glycosylation sites and CXC motifs in trafficking of Medicago trunculata Nod Factor Perception protein to the plasma membrane.

    NARCIS (Netherlands)

    Lefebvre, B.; Klaus-Heisen, D.; Pietraszewska-Bogiel, A.; Hervé, M.; Camut, S.; Auriac, M.C.; Gasciolli, V.; Nurisso, A.; Gadella, T.W.; Cullimore, J.

    2012-01-01

    The lysin motif receptor like kinase, NFP, is a key protein in the legume Medicago truncatula for the perception of lipochitooligosaccharidic Nod Factors, which are secreted bacterial signals essential for establishing the nitrogen-fixing legume-rhizobia symbiosis. Predicted structural and genetic a

  10. Interaction of Medicago truncatula Lysin Motif Receptor-Like Kinases, NFP and LYK3, Produced in Nicotiana benthamiana Induces Defence-Like Responses

    NARCIS (Netherlands)

    Pietraszewska-Bogiel, A.; Lefebvre, B.; Koini, A.M.; Klaus-Heisen, D.; Takken, F.L.W.; Geurts, R.; Cullimore, J.V.; Gadella, Th.W.J.

    2013-01-01

    Receptor(-like) kinases with Lysin Motif (LysM) domains in their extracellular region play crucial roles during plant interactions with microorganisms; e.g. Arabidopsis thaliana CERK1 activates innate immunity upon perception of fungal chitin/chitooligosaccharides, whereas Medicago truncatula NFP an

  11. In vivo characterization of the effects of abscisic acid and drying protocols associated with the acquisition of desiccation tolerance in alfalfa (Medicago sativa L.) somatic embryos

    NARCIS (Netherlands)

    Sreedhar, L.; Wolkers, W.F.; Hoekstra, F.A.; Bewley, J.D.

    2002-01-01

    Although somatic embryos of alfalfa (Medicago sativa L.) had acquired some tolerance to desiccation at the cotyledonary stage of development (22 d after plating), additional culturing in 20 ?M abscisic acid (ABA) for 8 d induced greater desiccation tolerance, as determined by increased germination.

  12. In vivo characterization of the effects of abscisic acid and drying protocols associated with the acquisition of desiccation tolerance in alfalfa (Medicago sativa L.) somatic embryos

    NARCIS (Netherlands)

    Sreedhar, L.; Wolkers, W.F.; Hoekstra, F.A.; Bewley, J.D.

    2002-01-01

    Although somatic embryos of alfalfa (Medicago sativa L.) had acquired some tolerance to desiccation at the cotyledonary stage of development (22 d after plating), additional culturing in 20 ?M abscisic acid (ABA) for 8 d induced greater desiccation tolerance, as determined by increased germination.

  13. Intuitionistic hybrid logic

    DEFF Research Database (Denmark)

    Braüner, Torben

    2011-01-01

    Intuitionistic hybrid logic is hybrid modal logic over an intuitionistic logic basis instead of a classical logical basis. In this short paper we introduce intuitionistic hybrid logic and we give a survey of work in the area.......Intuitionistic hybrid logic is hybrid modal logic over an intuitionistic logic basis instead of a classical logical basis. In this short paper we introduce intuitionistic hybrid logic and we give a survey of work in the area....

  14. Continuity Controlled Hybrid Automata

    OpenAIRE

    Bergstra, J. A.; Middelburg, C.A.

    2004-01-01

    We investigate the connections between the process algebra for hybrid systems of Bergstra and Middelburg and the formalism of hybrid automata of Henzinger et al. We give interpretations of hybrid automata in the process algebra for hybrid systems and compare them with the standard interpretation of hybrid automata as timed transition systems. We also relate the synchronized product operator on hybrid automata to the parallel composition operator of the process algebra. It turns out that the f...

  15. Hybridized tetraquarks

    Directory of Open Access Journals (Sweden)

    A. Esposito

    2016-07-01

    Full Text Available We propose a new interpretation of the neutral and charged X,Z exotic hadron resonances. Hybridized-tetraquarks are neither purely compact tetraquark states nor bound or loosely bound molecules but rather a manifestation of the interplay between the two. While meson molecules need a negative or zero binding energy, its counterpart for h-tetraquarks is required to be positive. The formation mechanism of this new class of hadrons is inspired by that of Feshbach metastable states in atomic physics. The recent claim of an exotic resonance in the Bs0π± channel by the D0 Collaboration and the negative result presented subsequently by the LHCb Collaboration are understood in this scheme, together with a considerable portion of available data on X,Z particles. Considerations on a state with the same quantum numbers as the X(5568 are also made.

  16. Hybridized Tetraquarks

    CERN Document Server

    Esposito, A.; Polosa, A.D.

    2016-01-01

    We propose a new interpretation of the neutral and charged X, Z exotic hadron resonances. Hybridized-tetraquarks are neither purely compact tetraquark states nor bound or loosely bound molecules. The latter would require a negative or zero binding energy whose counterpart in h-tetraquarks is a positive quantity. The formation mechanism of this new class of hadrons is inspired by that of Feshbach metastable states in atomic physics. The recent claim of an exotic resonance in the Bs pi+- channel by the D0 collaboration and the negative result presented subsequently by the LHCb collaboration are understood in this scheme, together with a considerable portion of available data on X, Z particles. Considerations on a state with the same quantum numbers as the X(5568) are also made.

  17. Study on the Extraction Method of Polysaccharide from Medicago Sativa%紫花苜蓿中多糖的提取方法研究

    Institute of Scientific and Technical Information of China (English)

    刘晓峰; 达哇卓玛; 杨国柱

    2013-01-01

    [Objective] The aim was to study the optimal extraction conditions of polysaccharide from Medicago sativa.[Method] The polysaccharide was extracted from Medicago sativa by using hot water extraction method.Effects of four factors like extraction time,extraction temperature,solid-liquid ratio and extraction times on the extracting rate of polysaccharide extracted from Medicago sativa were studied through single-factor experiment and orthogonal experiment.[Result] The optimal extraction conditions of polysaccharide from Medicago sativa were as followed:the extraction time was 1 h ; the extraction temperature was 95 ℃ ; the solid-liquid ratio was 1 ∶ 30 ; and the extracting time was three times.Under the above conditions,the extracting rate of polysaccharide was up to 6.1%.[Conclusion] The research results provides theoretical basis for the study and production of polysaccharide from Medicago sativa.%[目的]探究提取紫花苜蓿中多糖的最佳工艺条件.[方法]采用热水浸提法提取紫花苜蓿中多糖,并通过单因素试验和正交试验研究了浸提时间、浸提温度、浸提固液比、浸提次数对提取紫花苜蓿中多糖得率的影响.[结果]紫花苜蓿中多糖的最佳提取工艺条件为浸提时间1h、浸提温度95℃、固液比1∶30、浸提3次.在该最佳提取条件下,多糖的得率可达6.1%.[结论]为紫花苜蓿多糖的研究和生产提供了理论依据.

  18. A nitrogen-dependent switch in the high affinity ammonium transport in Medicago truncatula.

    Science.gov (United States)

    Straub, Daniel; Ludewig, Uwe; Neuhäuser, Benjamin

    2014-11-01

    Ammonium transporters (AMTs) are crucial for the high affinity primary uptake and translocation of ammonium in plants. In the model legume Medicago truncatula, the genomic set of AMT-type ammonium transporters comprises eight members. Only four genes were abundantly expressed in young seedlings, both in roots and shoots. While the expression of all AMTs in the shoot was not affected by the nitrogen availability, the dominating MtAMT1;1 gene was repressed by nitrogen in roots, despite that cellular nitrogen concentrations were far above deficiency levels. A contrasting de-repression by nitrogen was observed for MtAMT1;4 and MtAMT2;1, which were both expressed at intermediate level. Weak expression was found for MtAMT1;2 and MtAMT2;3, while the other AMTs were not detected in young seedlings. When expressed from their endogenous promoters, translational fusion proteins of MtAMT1;1 and MtAMT2;1 with green fluorescent protein were co-localized in the plasma membrane of rhizodermal cells, but also detected in cortical root layers. Both transporter proteins similarly functionally complemented a yeast strain that is deficient in high affinity ammonium transport, both at acidic and neutral pH. The uptake into yeast mediated by these transporters saturated with Km AMT1;1 = 89 µM and Km AMT2;1 = 123 µM, respectively. When expressed in oocytes, MtAMT1;1 mediated much larger (15)N-ammonium uptake than MtAMT2;1, but NH4 (+) currents were only recorded for MtAMT1;1. These currents saturated with a voltage-dependent Km = 90 µM at -80 mV. The cellular localization and regulation of the AMTs suggests that MtAMT1;1 encodes the major high affinity ammonium transporter gene in low nitrogen grown young M. truncatula roots and despite the similar localization and substrate affinity, MtAMT2;1 appears functionally distinct and more important at higher nitrogen supply.

  19. Genetic transformation and analysis of rice OsAPx2 gene in Medicago sativa.

    Directory of Open Access Journals (Sweden)

    Qingjie Guan

    Full Text Available The OsAPx2 gene from rice was cloned to produce PBI121::OsAPx2 dual-expression plants, of which expression level would be increasing under stressful conditions. The enzyme ascorbate peroxidase (APX in the leaves and roots of the plants increased with increasing exposure time to different sodium chloride (NaCl and hydrogen peroxide (H(2O(2concentrations, as indicated by protein gel blot analysis. The increased enzyme yield improved the ability of the plants to resist the stress treatments. The OsAPx2 gene was localized in the cytoplasm of epidermal onion cells as indicated by the instantaneous expression of green fluorescence. An 80% regeneration rate was observed in Medicago sativa L. plants transformed with the OsAPx2 gene using Agrobacterium tumefaciens, as indicated by specific primer PCR. The OsAPx2 gene was expressed at the mRNA level and the individual M. sativa (T#1,T#2,T#5 were obtained through assaying the generation of positive T2 using RNA gel blot analysis. When the seeds of the wild type (WT and the T2 (T#1,T#5 were incubated in culture containing MS with NaCl for 7 days, the results as shown of following: the root length of transgenic plant was longer than WT plants, the H(2O(2 content in roots of WT was more than of transgenic plants, the APX activity under stresses increased by 2.89 times compared with the WT, the malondialdehyde (MDA content of the WT was higher than the transgenic plants, the leaves of the WT turned yellow, but those of the transgenic plants remained green and remained healthy. The chlorophyll content in the WT leaves was less than in the transgenic plants, after soaking in solutions of H(2O(2, sodium sulfite (Na(2SO(3, and sodium bicarbonate (NaHCO(3. Therefore, the OsAPx2 gene overexpression in transgenic M. sativa improves the removal of H(2O(2 and the salt-resistance compared with WT plants. A novel strain of M. sativa carrying a salt-resistance gene was obtained.

  20. LTR retrotransposon landscape in Medicago truncatula: more rapid removal than in rice

    Directory of Open Access Journals (Sweden)

    Liu Jin-Song

    2008-08-01

    Full Text Available Abstract Background Long terminal repeat retrotransposons (LTR elements are ubiquitous Eukaryotic TEs that transpose through RNA intermediates. Accounting for significant proportion of many plant genomes, LTR elements have been well established as one of the major forces underlying the evolution of plant genome size, structure and function. The accessibility of more than 40% of genomic sequences of the model legume Medicago truncatula (Mt has made the comprehensive study of its LTR elements possible. Results We use a newly developed tool LTR_FINDER to identify LTR retrotransposons in the Mt genome and detect 526 full-length elements as well as a great number of copies related to them. These elements constitute about 9.6% of currently available genomic sequences. They are classified into 85 families of which 64 are reported for the first time. The majority of the LTR retrotransposons belong to either Copia or Gypsy superfamily and the others are categorized as TRIMs or LARDs by their length. We find that the copy-number of Copia-like families is 3 times more than that of Gypsy-like ones but the latter contribute more to the genome. The analysis of PBS and protein-coding domain structure of the LTR families reveals that they tend to use only 4–5 types of tRNAs and many families have quite conservative ORFs besides known TE domains. For several important families, we describe in detail their abundance, conservation, insertion time and structure. We investigate the amplification-deletion pattern of the elements and find that the detectable full-length elements are relatively young and most of them were inserted within the last 0.52 MY. We also estimate that more than ten million bp of the Mt genomic sequences have been removed by the deletion of LTR elements and the removal of the full-length structures in Mt has been more rapid than in rice. Conclusion This report is the first comprehensive description and analysis of LTR retrotransposons in the

  1. Exploring the plant-associated bacterial communities in Medicago sativa L

    Directory of Open Access Journals (Sweden)

    Pini Francesco

    2012-05-01

    Full Text Available Abstract Background Plant-associated bacterial communities caught the attention of several investigators which study the relationships between plants and soil and the potential application of selected bacterial species in crop improvement and protection. Medicago sativa L. is a legume crop of high economic importance as forage in temperate areas and one of the most popular model plants for investigations on the symbiosis with nitrogen fixing rhizobia (mainly belonging to the alphaproteobacterial species Sinorhizobium meliloti. However, despite its importance, no studies have been carried out looking at the total bacterial community associated with the plant. In this work we explored for the first time the total bacterial community associated with M. sativa plants grown in mesocosms conditions, looking at a wide taxonomic spectrum, from the class to the single species (S. meliloti level. Results Results, obtained by using Terminal-Restriction Fragment Length Polymorphism (T-RFLP analysis, quantitative PCR and sequencing of 16 S rRNA gene libraries, showed a high taxonomic diversity as well as a dominance by members of the class Alphaproteobacteria in plant tissues. Within Alphaproteobacteria the families Sphingomonadaceae and Methylobacteriaceae were abundant inside plant tissues, while soil Alphaproteobacteria were represented by the families of Hyphomicrobiaceae, Methylocystaceae, Bradyirhizobiaceae and Caulobacteraceae. At the single species level, we were able to detect the presence of S. meliloti populations in aerial tissues, nodules and soil. An analysis of population diversity on nodules and soil showed a relatively low sharing of haplotypes (30-40% between the two environments and between replicate mesocosms, suggesting drift as main force shaping S. meliloti population at least in this system. Conclusions In this work we shed some light on the bacterial communities associated with M. sativa plants, showing that Alphaproteobacteria may

  2. Transcriptomic changes induced by acute ozone in resistant and sensitive Medicago truncatula accessions

    Directory of Open Access Journals (Sweden)

    Mahalingam Ramamurthy

    2008-04-01

    Full Text Available Abstract Background Tropospheric ozone, the most abundant air pollutant is detrimental to plant and animal health including humans. In sensitive plant species even a few hours of exposure to this potent oxidant (200–300 nL. L-1 leads to severe oxidative stress that manifests as visible cell death. In resistant plants usually no visible symptoms are observed on exposure to similar ozone concentrations. Naturally occurring variability to acute ozone in plants provides a valuable resource for examining molecular basis of the differences in responses to ozone. From our earlier study in Medicago truncatula, we have identified cultivar Jemalong is ozone sensitive and PI 464815 (JE154 is an ozone-resistant accession. Analyses of transcriptome changes in ozone-sensitive and resistant accession will provide important clues for understanding the molecular changes governing the plant responses to ozone. Results Acute ozone treatment (300 nL L-1 for six hours led to a reactive oxygen species (ROS burst in sensitive Jemalong six hours post-fumigation. In resistant JE154 increase in ROS levels was much reduced compared to Jemalong. Based on the results of ROS profiling, time points for microarray analysis were one hour into the ozone treatment, end of treatment and onset of an ozone-induced ROS burst at 12 hours. Replicated temporal transcriptome analysis in these two accessions using 17 K oligonucleotide arrays revealed more than 2000 genes were differentially expressed. Significantly enriched gene ontologies (GOs were identified using the Cluster Enrichment analysis program. A striking finding was the alacrity of JE154 in altering its gene expression patterns in response to ozone, in stark contrast to delayed transcriptional response of Jemalong. GOs involved in signaling, hormonal pathways, antioxidants and secondary metabolism were altered in both accessions. However, the repertoire of genes responding in each of these categories was different between

  3. Biogenic Pt uptake and nanoparticle formation in Medicago sativa and Brassica juncea

    Energy Technology Data Exchange (ETDEWEB)

    Bali, Roza [University of Sydney, Laboratory for Sustainable Technology, School of Chemical and Biomolecular Engineering (Australia); Siegele, Rainer [Australian Nuclear Science and Technology Organization, Institute for Environmental Research (Australia); Harris, Andrew T., E-mail: a.harris@usyd.edu.a [University of Sydney, Laboratory for Sustainable Technology, School of Chemical and Biomolecular Engineering (Australia)

    2010-10-15

    The ability of the facultative metallophyte plants, Medicago sativa (M. sativa) and Brassica juncea (B. juncea) to accumulate and translocate platinum (Pt) from aqueous substrates is reported. The influence of Pt concentration in the substrate (5, 10, 20, 40 and 80 ppm), exposure time (24, 48 and 72 h) and substrate pH (2, 3, 5, 7 and 9) was determined. In both plants the concentration of Pt increased with substrate concentration and exposure time. Greater accumulation was detected in the roots of M. sativa than B. juncea, up to a maximum of 94.19 mg Pt g{sup -1} (dry biomass) compared with 38.5 mg Pt g{sup -1} (dry biomass) following exposure to 80 ppm Pt after 72 h exposure, respectively. However, at lower substrate concentrations (5 and 20 ppm) greater quantities of Pt were detected in the shoots of B. juncea, ranging between 0.02 and 0.32 mg Pt g{sup -1} (dry biomass) at 5 ppm across the different time intervals studied, compared with 0.02-0.14 mg Pt g{sup -1} (dry biomass) for M. sativa, suggesting B. juncea to be a better translocator of Pt under idealised conditions at low concentrations. Higher Pt uptake was also observed in acidic media, with a maximum at pH 2 for M. sativa and pH 3 for B. juncea, indicating the role of net surface charge on the bioaccumulation of Pt. Once sequestered Pt(II) was reduced to Pt(0) due to the action of local metabolites. TEM images of M. sativa root samples showed the in vivo formation of Pt nanoparticles between 3 and 100 nm in size and of varying morphologies in the epidermal root cells. In vivo Pt distribution profiles were assessed using proton induced X-ray emission ({mu}-PIXE) spectroscopy, which showed even distribution across all tissue systems (epidermal, cortical and vascular) within the roots of both M. sativa and B. juncea.

  4. Genome-Wide Association Mapping and Genomic Selection for Alfalfa (Medicago sativa) Forage Quality Traits

    Science.gov (United States)

    Pecetti, Luciano; Brummer, E. Charles; Palmonari, Alberto; Tava, Aldo

    2017-01-01

    Genetic progress for forage quality has been poor in alfalfa (Medicago sativa L.), the most-grown forage legume worldwide. This study aimed at exploring opportunities for marker-assisted selection (MAS) and genomic selection of forage quality traits based on breeding values of parent plants. Some 154 genotypes from a broadly-based reference population were genotyped by genotyping-by-sequencing (GBS), and phenotyped for leaf-to-stem ratio, leaf and stem contents of protein, neutral detergent fiber (NDF) and acid detergent lignin (ADL), and leaf and stem NDF digestibility after 24 hours (NDFD), of their dense-planted half-sib progenies in three growing conditions (summer harvest, full irrigation; summer harvest, suspended irrigation; autumn harvest). Trait-marker analyses were performed on progeny values averaged over conditions, owing to modest germplasm × condition interaction. Genomic selection exploited 11,450 polymorphic SNP markers, whereas a subset of 8,494 M. truncatula-aligned markers were used for a genome-wide association study (GWAS). GWAS confirmed the polygenic control of quality traits and, in agreement with phenotypic correlations, indicated substantially different genetic control of a given trait in stems and leaves. It detected several SNPs in different annotated genes that were highly linked to stem protein content. Also, it identified a small genomic region on chromosome 8 with high concentration of annotated genes associated with leaf ADL, including one gene probably involved in the lignin pathway. Three genomic selection models, i.e., Ridge-regression BLUP, Bayes B and Bayesian Lasso, displayed similar prediction accuracy, whereas SVR-lin was less accurate. Accuracy values were moderate (0.3–0.4) for stem NDFD and leaf protein content, modest for leaf ADL and NDFD, and low to very low for the other traits. Along with previous results for the same germplasm set, this study indicates that GBS data can be exploited to improve both quality traits

  5. Genetic transformation and analysis of rice OsAPx2 gene in Medicago sativa.

    Science.gov (United States)

    Guan, Qingjie; Takano, Tetsuo; Liu, Shenkui

    2012-01-01

    The OsAPx2 gene from rice was cloned to produce PBI121::OsAPx2 dual-expression plants, of which expression level would be increasing under stressful conditions. The enzyme ascorbate peroxidase (APX) in the leaves and roots of the plants increased with increasing exposure time to different sodium chloride (NaCl) and hydrogen peroxide (H(2)O(2))concentrations, as indicated by protein gel blot analysis. The increased enzyme yield improved the ability of the plants to resist the stress treatments. The OsAPx2 gene was localized in the cytoplasm of epidermal onion cells as indicated by the instantaneous expression of green fluorescence. An 80% regeneration rate was observed in Medicago sativa L. plants transformed with the OsAPx2 gene using Agrobacterium tumefaciens, as indicated by specific primer PCR. The OsAPx2 gene was expressed at the mRNA level and the individual M. sativa (T#1,T#2,T#5) were obtained through assaying the generation of positive T2 using RNA gel blot analysis. When the seeds of the wild type (WT) and the T2 (T#1,T#5) were incubated in culture containing MS with NaCl for 7 days, the results as shown of following: the root length of transgenic plant was longer than WT plants, the H(2)O(2) content in roots of WT was more than of transgenic plants, the APX activity under stresses increased by 2.89 times compared with the WT, the malondialdehyde (MDA) content of the WT was higher than the transgenic plants, the leaves of the WT turned yellow, but those of the transgenic plants remained green and remained healthy. The chlorophyll content in the WT leaves was less than in the transgenic plants, after soaking in solutions of H(2)O(2), sodium sulfite (Na(2)SO(3)), and sodium bicarbonate (NaHCO(3)). Therefore, the OsAPx2 gene overexpression in transgenic M. sativa improves the removal of H(2)O(2) and the salt-resistance compared with WT plants. A novel strain of M. sativa carrying a salt-resistance gene was obtained.

  6. Continuity Controlled Hybrid Automata

    NARCIS (Netherlands)

    Bergstra, J.A.; Middelburg, C.A.

    2004-01-01

    We investigate the connections between the process algebra for hybrid systems of Bergstra and Middelburg and the formalism of hybrid automata of Henzinger et al. We give interpretations of hybrid automata in the process algebra for hybrid systems and compare them with the standard interpretation of

  7. Continuity controlled Hybrid Automata

    NARCIS (Netherlands)

    Bergstra, J.A.; Middelburg, C.A.

    2008-01-01

    We investigate the connections between the process algebra for hybrid systems of Bergstra and Middelburg and the formalism of hybrid automata of Henzinger et al. We give interpretations of hybrid automata in the process algebra for hybrid systems and compare them with the standard interpretation of

  8. Identification of genetic loci associated with crude protein and mineral concentrations in alfalfa (Medicago sativa) using association mapping.

    Science.gov (United States)

    Jia, Congjun; Wu, Xinming; Chen, Min; Wang, Yunqi; Liu, Xiqiang; Gong, Pan; Xu, Qingfang; Wang, Xuemin; Gao, Hongwen; Wang, Zan

    2017-06-06

    Alfalfa (Medicago sativa) is one of the most important legume forage species in China and many other countries of the world. It provides a quality source of proteins and minerals to animals. Genetic underpinnings for these important traits, however, are elusive. An alfalfa (M. sativa) association mapping study for six traits, namely crude protein (CP), rumen undegraded protein (RUP), and four mineral elements (Ca, K, Mg and P), was conducted in three consecutive years using a large collection encompassing 336 genotypes genotyped with 85 simple sequence repeat (SSR) markers. All the traits were significantly influenced by genotype, environment, and genotype × environment interaction. Eight-five significant associations (P alfalfa quality. The markers could be used in assisting selection for the individual traits in breeding populations for developing new alfalfa cultivars.

  9. Medicago sativa L. cv. Longmu 807 Breeding Report%龙牧807苜蓿选育报告

    Institute of Scientific and Technical Information of China (English)

    李红; 杨伟光; 黄新育; 杨曌; 毛小涛

    2011-01-01

    Medicago sativa L. cv. Longmu 807, a forage crop cultivar selected from initial population of Medicago sativa L. cv. Longmu 803, had been bred through 12 successive generations by choosing good single plant in the initial population, then asexual propagation and three time mixed choice as well as open pollination. The new cultivar had been checked by comparative tests of varieties, regional test and production test in different ecological zones. The plant is erect and the plant height reached 75.7~105.3 cm in flowering stage and 98.5~133.8 cm in maturity stage. The growing period was about 120 days and turned green during late April in Heilongjiang. The average hay yield was 11739.14 kg ·hm-2 and increased 17.10% compared with control alfalfa Longmu 803(9797.99 kg · hm-2). The average seed yield was 284.60 kg · hm-2, increased 18.25% compared with control alfalfa Longmu 803(230.00 kg ·bm-2). The alfalfa Longmu 807 has good palatability and its crude protein contents are 19.38% at early flowering stage.Moreover, the plant has strong resistance ability and ecological adapt ability. It is suitable to be cultivated in HeiLongjiang or other province around HeiLongjiang.%从龙牧803(Medicago sativa L.cv.Longmu 803)苜蓿群体中选择优秀单株,通过无性扦插繁殖,3次混合选择、开放授粉及品种比较试验、区域与生产试验,历经12年育成龙牧807苜蓿(Medicago sativa L.cv.Longmu 807)新品种.该品种株型直立,在黑龙江省地区4月中下旬返青,生育期120 d左右,开花期株高75.7~105.3cm,成熟期株高98.5~133.8 cm.2年生干草产量为11739.14 kg·hm-2,比对照龙牧803苜蓿(9797.99 kg·hm-1)增产17.10%;种子产量284.60 kg·hm-2,比对照(230.00 kg·hm-2)增产18.25%.初花期粗蛋白含量19.38%,适口性好,饲用品质优良.其抗性强,生态适应性广,适宜在黑龙江省各地及毗邻省区推广种植.

  10. Characterization of the secretome of suspension cultures of Medicago species reveals proteins important for defense and development.

    Science.gov (United States)

    Kusumawati, Lucia; Imin, Nijat; Djordjevic, Michael A

    2008-10-01

    Molecular events occurring in the plant apoplast contribute to important developmental and defense responses. To define the secretome of Medicago, we used suspension cultures to isolate and identify secreted proteins as a first step to determining their functions. Proteins in the extracellular medium of the suspension cultures were examined using SDS-PAGE, tandem mass spectrometry (MALDI-TOF/TOF) and bioinformatics tools. There were 39 proteins identified in the cultures derived from M. sativa, M. truncatula 2HA (an embryogenic line), and M. truncatula sickle (an ethylene-insensitive mutant). N-Terminal secretion signals were detected in 34 proteins and five other proteins were predicted to be secreted via a nonclassical (ER-independent) route. All samples possessed defense related proteins including pathogenesis related (PR) proteins. The glycoprotein, SIEP1L, was found only in M. sativa. Three secreted proteinases were identified in M. truncatula, including a serine carboxypeptidase detected only in 2HA. Some proteins were unique to a cell culture line. Quantitative real time RT-PCR was used to determine mRNA expression of selected genes corresponding to proteins found only in 2HA or sickle or in both. The results correlate well with the proteomic data. For instance, a GDSL-lipase gene known to be regulated by ethylene was found only in 2HA but not in the ethylene insensitive mutant. Similarly, the PR1a protein, expressed from a well recognized ethylene-regulated gene, was found in 2HA but not sickle. These experiments indicate that the suspension culture systems established here are useful to avoid contamination from cytoplasmic proteins and to identify secreted proteins in Medicago, and should have application in other plant systems.

  11. Identification of a dominant gene in Medicago truncatula that restricts nodulation by Sinorhizobium meliloti strain Rm41

    Science.gov (United States)

    2014-01-01

    Background Leguminous plants are able to form a root nodule symbiosis with nitrogen-fixing soil bacteria called rhizobia. This symbiotic association shows a high level of specificity. Beyond the specificity for the legume family, individual legume species/genotypes can only interact with certain restricted group of bacterial species or strains. Specificity in this system is regulated by complex signal exchange between the two symbiotic partners and thus multiple genetic mechanisms could be involved in the recognition process. Knowledge of the molecular mechanisms controlling symbiotic specificity could enable genetic improvement of legume nitrogen fixation, and may also reveal the possible mechanisms that restrict root nodule symbiosis in non-legumes. Results We screened a core collection of Medicago truncatula genotypes with several strains of Sinorhizobium meliloti and identified a naturally occurring dominant gene that restricts nodulation by S. meliloti Rm41. We named this gene as Mt-NS1 (for M.truncatulanodulation specificity 1). We have mapped the Mt-NS1 locus within a small genomic region on M. truncatula chromosome 8. The data reported here will facilitate positional cloning of the Mt-NS1 gene. Conclusions Evolution of symbiosis specificity involves both rhizobial and host genes. From the bacterial side, specificity determinants include Nod factors, surface polysaccharides, and secreted proteins. However, we know relatively less from the host side. We recently demonstrated that a component of this specificity in soybeans is defined by plant NBS-LRR resistance (R) genes that recognize effector proteins delivered by the type III secretion system (T3SS) of the rhizobial symbionts. However, the lack of a T3SS in many sequenced S. meliloti strains raises the question of how the specificity is regulated in the Medicago-Sinorhizobium system beyond Nod-factor perception. Thus, cloning and characterization of Mt-NS1 will add a new dimension to our knowledge about

  12. Effects of salinity and drought stress on germination, biomass and growth in three varieties of Medicago sativa L.

    Directory of Open Access Journals (Sweden)

    A. Castroluna

    2014-01-01

    Full Text Available En plántulas de alfalfa (Medicago sativa L. se evaluó la germinación y el crecimiento y su tolerancia al estrés osmótico inducido por Polietilenglicol 6000 (PEG6000 y salinidad (NaCl en tres genotipos distintos: Dk166, Verdor y Salina. Esta investigación se llevó a cabo con un diseño experimental completamente aleatorizado, con cinco réplicas y los parámetros que se determinaron fueron: energía y poder germinativo, largo de hojas y peso fresco y peso seco de raíces y hojas. Los resultados mostraron que la germinación fue retrasada en todas las variedades con ambas soluciones, con diferencias entre genotipos. El crecimiento de las plántulas, bajo un ligero estrés mostraron un incremento de la biomasa aérea y en un estrés hídrico y salino severo, muerte de las plantas excepto en Var. Salina (tolerante. PEG causó muerte en la variedad Verdor que mostró más sensibilidad a PEG que a NaCl. En raíces, los genotipos más sensibles frente a leves estrés salinos detuvieron su crecimiento y bajo leves situaciones de estrés hídrico lo incrementaron. Nuestros estudios nos permiten definir las variedades comerciales de Medicago sativa como moderadamente tolerantes a salinidad y sequía la variedad DK166, sensible o intolerante a salinidad y sequía la variedad Verdor y con una alta tolerancia a salinidad e insensible a sequía la variedad Salina.

  13. Molecular docking of Glycine max and Medicago truncatula ureases with urea; bioinformatics approaches.

    Science.gov (United States)

    Filiz, Ertugrul; Vatansever, Recep; Ozyigit, Ibrahim Ilker

    2016-03-01

    Urease (EC 3.5.1.5) is a nickel-dependent metalloenzyme catalyzing the hydrolysis of urea into ammonia and carbon dioxide. It is present in many bacteria, fungi, yeasts and plants. Most species, with few exceptions, use nickel metalloenzyme urease to hydrolyze urea, which is one of the commonly used nitrogen fertilizer in plant growth thus its enzymatic hydrolysis possesses vital importance in agricultural practices. Considering the essentiality and importance of urea and urease activity in most plants, this study aimed to comparatively investigate the ureases of two important legume species such as Glycine max (soybean) and Medicago truncatula (barrel medic) from Fabaceae family. With additional plant species, primary and secondary structures of 37 plant ureases were comparatively analyzed using various bioinformatics tools. A structure based phylogeny was constructed using predicted 3D models of G. max and M. truncatula, whose crystallographic structures are not available, along with three additional solved urease structures from Canavalia ensiformis (PDB: 4GY7), Bacillus pasteurii (PDB: 4UBP) and Klebsiella aerogenes (PDB: 1FWJ). In addition, urease structures of these species were docked with urea to analyze the binding affinities, interacting amino acids and atom distances in urease-urea complexes. Furthermore, mutable amino acids which could potentially affect the protein active site, stability and flexibility as well as overall protein stability were analyzed in urease structures of G. max and M. truncatula. Plant ureases demonstrated similar physico-chemical properties with 833-878 amino acid residues and 89.39-90.91 kDa molecular weight with mainly acidic (5.15-6.10 pI) nature. Four protein domain structures such as urease gamma, urease beta, urease alpha and amidohydro 1 characterized the plant ureases. Secondary structure of plant ureases also demonstrated conserved protein architecture, with predominantly α-helix and random coil structures. In

  14. 苜蓿酯酶的提取分离及性质测定%Extract and activity of medicago sative esterase

    Institute of Scientific and Technical Information of China (English)

    王亚飞; 张金艳

    2012-01-01

    The esterase is extracted from medicago sative. After purification, the effects of the pH value, temperature, the species and the concetration of salts are studied. The result shows: the activity of esterase is the highest at 40℃ in phosphate buffered solution (with the pH of 7.0).%从苜蓿(Medicago sative)中提取植物酯酶并纯化,分别测定pH值、温度、盐的种类和浓度对酶活的影响。实验结果表明,用pH7.0的0.1mol/L磷酸盐缓冲溶液提取的酯酶活性最高,40℃时酯酶反应活性最大。

  15. Detection of Changes in the Medicago sativa Retinoblastoma-Related Protein (MsRBR1) Phosphorylation During Cell Cycle Progression in Synchronized Cell Suspension Culture.

    Science.gov (United States)

    Ayaydin, Ferhan; Kotogány, Edit; Ábrahám, Edit; Horváth, Gábor V

    2017-01-01

    Deepening our knowledge on the regulation of the plant cell division cycle depends on techniques that allow for the enrichment of cell populations in defined cell cycle phases. Synchronization of cell division can be achieved using different plant tissues; however, well-established cell suspension cultures provide large amount of biological sample for further analyses. Here, we describe the methodology of the establishment, propagation, and analysis of a Medicago sativa suspension culture that can be used for efficient synchronization of the cell division. A novel 5-ethynyl-2'-deoxyuridine (EdU)-based method is used for the estimation of cell fraction that enters DNA synthesis phase of the cell cycle and we also demonstrate the changes in the phosphorylation level of Medicago sativa retinoblastoma-related protein (MsRBR1) during cell cycle progression.

  16. Pilot study on diffusive ground heat storage in the SUVA 'D4' building complex in Root, Switzerland; Etude pilote pour le stockage diffusif des batiments du centre D4 de la SUVA a Root, Lucerne. Analyse de 2 tests de reponse geothermique et integration du stockage diffusif dans le systeme

    Energy Technology Data Exchange (ETDEWEB)

    Pahud, D.

    2001-07-01

    This report for the Swiss Federal Office of Energy (SFOE) presents, in a first part, the results of two thermal response tests made on a geothermal heat storage system that forms part of a heating and cooling system for a complex of buildings comprising the 'D4' centre of the Swiss Accident Insurance Institution (SUVA) in Root, near Lucerne, Switzerland. These in situ response tests on two borehole heat exchangers confirmed the laboratory measurements, indicating that no significant ground water flow is present. In a second part the heat storage dimensioning and the heating/cooling system evaluation by means of computerized simulation are described, which used simulated data for the heating and cooling requirements of the new buildings and the ground heat storage parameters. The PILESIM thermal simulation tool is described, a computer code used to simulate heating and cooling systems that use heat-exchanger piles or borehole heat exchangers. The evaluations made on three system concepts are discussed that permitted the optimal design of the diffusive ground storage system. The construction of the actual system is also described.

  17. Co-transforming bar and CsALDH Genes Enhanced Resistance to Herbicide and Drought and Salt Stress in Transgenic Alfalfa (Medicago sativa L.)

    OpenAIRE

    Duan, Zhen; Zhang, Daiyu; Zhang, Jianquan; Di, Hongyan; Wu, Fan; Hu, Xiaowen; Meng, Xuanchen; Luo, Kai; Zhang, Jiyu; Wang, Yanrong

    2015-01-01

    Drought and high salinity are two major abiotic factors that restrict the productivity of alfalfa. By application of the Agrobacterium-mediated transformation method, an oxidative responsive gene, CsALDH12A1, from the desert grass Cleistogenes songorica together with the bar gene associated with herbicide resistance, were co-transformed into alfalfa (Medicago sativa L.). From the all 90 transformants, 16 were positive as screened by spraying 1 mL L-1 10% Basta solution and molecularly diagnos...

  18. Effect of different fertilizing and farming systems in annual medic (Medicago scutellata ’Robinson’) on soil organic matter and nutrients status

    OpenAIRE

    Ghobad Shabani; M. R. Chaichi; Mohammad Reza Ardakani; J. K. FRIDEL; K. Khavazi

    2017-01-01

    This experiment was conducted to study the effect of different fertilizing and farming systems in annual medic (Medicago scutellata ‘Robinson’) on soil organic matter and nutrients status. Fertilizing systems consisted of control (no fertilizer), chemical fertilizer, biological fertilizer and integrated fertilizers (different combinations of chemical and biological fertilizing systems). The farming systems included irrigated and dry-farming systems. The experiment was conducted in two experim...

  19. Interaction of Medicago truncatula Lysin Motif Receptor-Like Kinases, NFP and LYK3, Produced in Nicotiana benthamiana Induces Defence-Like Responses

    OpenAIRE

    2013-01-01

    Receptor(-like) kinases with Lysin Motif (LysM) domains in their extracellular region play crucial roles during plant interactions with microorganisms; e.g. Arabidopsis thaliana CERK1 activates innate immunity upon perception of fungal chitin/chitooligosaccharides, whereas Medicago truncatula NFP and LYK3 mediate signalling upon perception of bacterial lipo-chitooligosaccharides, termed Nod factors, during the establishment of mutualism with nitrogen-fixing rhizobia. However, little is still ...

  20. Establishment of a root proteome reference map for the model legume Medicago truncatula using the expressed sequence tag database for peptide mass fingerprinting

    DEFF Research Database (Denmark)

    Mathesius, U; Keijzers, Guido; Natera, S H

    2001-01-01

    We have established a proteome reference map for Medicago truncatula root proteins using two-dimensional gel electrophoresis combined with peptide mass fingerprinting to aid the dissection of nodulation and root developmental pathways by proteome analysis. M. truncatula has been chosen as a model....... This proteome map will be updated continuously (http://semele.anu.edu.au/2d/2d.html) and will be a powerful tool for investigating the molecular mechanisms of root symbioses in legumes....

  1. In vivo Characterization of the Effects of Abscisic Acid and Drying Protocols Associated with the Acquisition of Desiccation Tolerance in Alfalfa (Medicago sativa L.) Somatic Embryos

    OpenAIRE

    SREEDHAR, LEKHA; Wolkers, Willem F.; Hoekstra, Folkert A.; BEWLEY, J. DEREK

    2002-01-01

    Although somatic embryos of alfalfa (Medicago sativa L.) had acquired some tolerance to desiccation at the cotyledonary stage of development (22 d after plating), additional culturing in 20 μm abscisic acid (ABA) for 8 d induced greater desiccation tolerance, as determined by increased germination. Compared with fast drying, slow drying of the ABA‐treated embryos improved desiccation tolerance. However, slow drying of non‐ABA‐treated embryos led to the complete loss of germination capacity, w...

  2. The impact of using alternative forages on the nutrient value within slurry and its implications for forage productivity in agricultural systems.

    Directory of Open Access Journals (Sweden)

    Felicity V Crotty

    Full Text Available Alternative forages can be used to provide valuable home-grown feed for ruminant livestock. Utilising these different forages could affect the manure value and the implications of incorporating these forages into farming systems, needs to be better understood. An experiment tested the hypothesis that applying slurries from ruminants, fed ensiled red clover (Trifolium pratense, lucerne (Medicago sativa or kale (Brassica oleracea would improve the yield of hybrid ryegrass (Lolium hybridicum, compared with applying slurries from ruminants fed ensiled hybrid ryegrass, or applying inorganic N alone. Slurries from sheep offered one of four silages were applied to ryegrass plots (at 35 t ha⁻¹ with 100 kg N ha⁻¹ inorganic fertiliser; dry matter (DM yield was compared to plots only receiving ammonium nitrate at rates of 0, 100 and 250 kg N ha⁻¹ year-1. The DM yield of plots treated with 250 kg N, lucerne or red clover slurry was significantly higher than other treatments (Pred clover (81 kg >kale (44 kg >ryegrass (26 kg ha⁻¹ yr⁻¹. These FNE values represent relative efficiencies of 22% (ryegrass, 52% (kale, 47% (red clover and 60% for lucerne slurry, with the ryegrass slurry efficiency being lowest (P = 0.005. Soil magnesium levels in plots treated with legume slurry were higher than other treatments (P<0.001. Overall, slurries from ruminants fed alternative ensiled forages increased soil nutrient status, forage productivity and better N efficiency than slurries from ruminants fed ryegrass silage. The efficiency of fertiliser use is one of the major factors influencing the sustainability of farming systems, these findings highlight the cascade in benefits from feeding ruminants alternative forages, and the need to ensure their value is effectively captured to reduce environmental risks.

  3. The impact of using alternative forages on the nutrient value within slurry and its implications for forage productivity in agricultural systems.

    Science.gov (United States)

    Crotty, Felicity V; Fychan, Rhun; Theobald, Vince J; Sanderson, Ruth; Chadwick, David R; Marley, Christina L

    2014-01-01

    Alternative forages can be used to provide valuable home-grown feed for ruminant livestock. Utilising these different forages could affect the manure value and the implications of incorporating these forages into farming systems, needs to be better understood. An experiment tested the hypothesis that applying slurries from ruminants, fed ensiled red clover (Trifolium pratense), lucerne (Medicago sativa) or kale (Brassica oleracea) would improve the yield of hybrid ryegrass (Lolium hybridicum), compared with applying slurries from ruminants fed ensiled hybrid ryegrass, or applying inorganic N alone. Slurries from sheep offered one of four silages were applied to ryegrass plots (at 35 t ha⁻¹) with 100 kg N ha⁻¹ inorganic fertiliser; dry matter (DM) yield was compared to plots only receiving ammonium nitrate at rates of 0, 100 and 250 kg N ha⁻¹ year-1. The DM yield of plots treated with 250 kg N, lucerne or red clover slurry was significantly higher than other treatments (Pred clover (81 kg) >kale (44 kg) >ryegrass (26 kg ha⁻¹ yr⁻¹). These FNE values represent relative efficiencies of 22% (ryegrass), 52% (kale), 47% (red clover) and 60% for lucerne slurry, with the ryegrass slurry efficiency being lowest (P = 0.005). Soil magnesium levels in plots treated with legume slurry were higher than other treatments (Psilage. The efficiency of fertiliser use is one of the major factors influencing the sustainability of farming systems, these findings highlight the cascade in benefits from feeding ruminants alternative forages, and the need to ensure their value is effectively captured to reduce environmental risks.

  4. From hybrid swarms to swarms of hybrids

    Science.gov (United States)

    The introgression of modern humans (Homo sapiens) with Neanderthals 40,000 YBP after a half-million years of separation, may have led to the best example of a hybrid swarm on earth. Modern trade and transportation in support of the human hybrids has continued to introduce additional species, genotyp...

  5. The Hybrid Museum: Hybrid Economies of Meaning

    DEFF Research Database (Denmark)

    Vestergaard, Vitus

    2013-01-01

    this article shows that there are two different museum mindsets where the second mindset leans towards participatory practices. It is shown how a museum can support a hybrid economy of meaning that builds on both a user generated economy of meaning and an institutional economy of meaning and adds value to both....... Such a museum is referred to as a hybrid museum....

  6. Hydraulic Hybrid Vehicles

    Science.gov (United States)

    EPA and the United Parcel Service (UPS) have developed a hydraulic hybrid delivery vehicle to explore and demonstrate the environmental benefits of the hydraulic hybrid for urban pick-up and delivery fleets.

  7. Hybrid Management in Hospitals

    DEFF Research Database (Denmark)

    Byrkjeflot, Haldor; Jespersen, Peter Kragh

    2010-01-01

    Artiklen indeholder et litteraturbaseret studium af ledelsesformer i sygehuse, hvor sundhedsfaglig ledelse og generel ledelse mikses til hybride ledelsesformer......Artiklen indeholder et litteraturbaseret studium af ledelsesformer i sygehuse, hvor sundhedsfaglig ledelse og generel ledelse mikses til hybride ledelsesformer...

  8. Resin Catalyst Hybrids

    Institute of Scientific and Technical Information of China (English)

    S. Asaoka

    2005-01-01

    @@ 1Introduction: What are resin catalyst hybrids? There are typically two types of resin catalyst. One is acidic resin which representative is polystyrene sulfonic acid. The other is basic resin which is availed as metal complex support. The objective items of this study on resin catalyst are consisting of pellet hybrid, equilibrium hybrid and function hybrid of acid and base,as shown in Fig. 1[1-5].

  9. Mesoscale hybrid calibration artifact

    Science.gov (United States)

    Tran, Hy D.; Claudet, Andre A.; Oliver, Andrew D.

    2010-09-07

    A mesoscale calibration artifact, also called a hybrid artifact, suitable for hybrid dimensional measurement and the method for make the artifact. The hybrid artifact has structural characteristics that make it suitable for dimensional measurement in both vision-based systems and touch-probe-based systems. The hybrid artifact employs the intersection of bulk-micromachined planes to fabricate edges that are sharp to the nanometer level and intersecting planes with crystal-lattice-defined angles.

  10. Realizing the Hybrid Library.

    Science.gov (United States)

    Pinfield, Stephen; Eaton, Jonathan; Edwards, Catherine; Russell, Rosemary; Wissenburg, Astrid; Wynne, Peter

    1998-01-01

    Outlines five projects currently funded by the United Kingdom's Electronic Libraries Program (eLib): HyLiFe (Hybrid Library of the Future), MALIBU (MAnaging the hybrid Library for the Benefit of Users), HeadLine (Hybrid Electronic Access and Delivery in the Library Networked Environment), ATHENS (authentication scheme), and BUILDER (Birmingham…

  11. Homoploid hybrid expectations

    Science.gov (United States)

    Homoploid hybrid speciation occurs when a stable, fertile, and reproductively isolated lineage results from hybridization between two distinct species without a change in ploidy level. Reproductive isolation between a homoploid hybrid species and its parents is generally attained via chromosomal re...

  12. Hybrid armature projectile

    Science.gov (United States)

    Hawke, Ronald S.; Asay, James R.; Hall, Clint A.; Konrad, Carl H.; Sauve, Gerald L.; Shahinpoor, Mohsen; Susoeff, Allan R.

    1993-01-01

    A projectile for a railgun that uses a hybrid armature and provides a seed block around part of the outer surface of the projectile to seed the hybrid plasma brush. In addition, the hybrid armature is continuously vaporized to replenish plasma in a plasma armature to provide a tandem armature and provides a unique ridge and groove to reduce plasama blowby.

  13. Intraply Hybrid Composite Design

    Science.gov (United States)

    Chamis, C. C.; Sinclair, J. H.

    1986-01-01

    Several theoretical approaches combined in program. Intraply hybrid composites investigated theoretically and experimentally at Lewis Research Center. Theories developed during investigations and corroborated by attendant experiments used to develop computer program identified as INHYD (Intraply Hybrid Composite Design). INHYD includes several composites micromechanics theories, intraply hybrid composite theories, and integrated hygrothermomechanical theory. Equations from theories used by program as appropriate for user's specific applications.

  14. Hybrid quantum information processing

    Energy Technology Data Exchange (ETDEWEB)

    Furusawa, Akira [Department of Applied Physics, School of Engineering, The University of Tokyo (Japan)

    2014-12-04

    I will briefly explain the definition and advantage of hybrid quantum information processing, which is hybridization of qubit and continuous-variable technologies. The final goal would be realization of universal gate sets both for qubit and continuous-variable quantum information processing with the hybrid technologies. For that purpose, qubit teleportation with a continuousvariable teleporter is one of the most important ingredients.

  15. The hydrogen hybrid option

    Energy Technology Data Exchange (ETDEWEB)

    Smith, J.R.

    1993-10-15

    The energy efficiency of various piston engine options for series hybrid automobiles are compared with conventional, battery powered electric, and proton exchange membrane (PEM) fuel cell hybrid automobiles. Gasoline, compressed natural gas (CNG), and hydrogen are considered for these hybrids. The engine and fuel comparisons are done on a basis of equal vehicle weight, drag, and rolling resistance. The relative emissions of these various fueled vehicle options are also presented. It is concluded that a highly optimized, hydrogen fueled, piston engine, series electric hybrid automobile will have efficiency comparable to a similar fuel cell hybrid automobile and will have fewer total emissions than the battery powered vehicle, even without a catalyst.

  16. Hybridization and extinction.

    Science.gov (United States)

    Todesco, Marco; Pascual, Mariana A; Owens, Gregory L; Ostevik, Katherine L; Moyers, Brook T; Hübner, Sariel; Heredia, Sylvia M; Hahn, Min A; Caseys, Celine; Bock, Dan G; Rieseberg, Loren H

    2016-08-01

    Hybridization may drive rare taxa to extinction through genetic swamping, where the rare form is replaced by hybrids, or by demographic swamping, where population growth rates are reduced due to the wasteful production of maladaptive hybrids. Conversely, hybridization may rescue the viability of small, inbred populations. Understanding the factors that contribute to destructive versus constructive outcomes of hybridization is key to managing conservation concerns. Here, we survey the literature for studies of hybridization and extinction to identify the ecological, evolutionary, and genetic factors that critically affect extinction risk through hybridization. We find that while extinction risk is highly situation dependent, genetic swamping is much more frequent than demographic swamping. In addition, human involvement is associated with increased risk and high reproductive isolation with reduced risk. Although climate change is predicted to increase the risk of hybridization-induced extinction, we find little empirical support for this prediction. Similarly, theoretical and experimental studies imply that genetic rescue through hybridization may be equally or more probable than demographic swamping, but our literature survey failed to support this claim. We conclude that halting the introduction of hybridization-prone exotics and restoring mature and diverse habitats that are resistant to hybrid establishment should be management priorities.

  17. Spoof Plasmon Hybridization

    CERN Document Server

    Zhang, Jingjing; Luo, Yu; Shen, Xiaopeng; Maier, Stefan A; Cui, Tie Jun

    2016-01-01

    Plasmon hybridization between closely spaced nanoparticles yields new hybrid modes not found in individual constituents, allowing for the engineering of resonance properties and field enhancement capabilities of metallic nanostructure. Experimental verifications of plasmon hybridization have been thus far mostly limited to optical frequencies, as metals cannot support surface plasmons at longer wavelengths. Here, we introduce the concept of 'spoof plasmon hybridization' in highly conductive metal structures and investigate experimentally the interaction of localized surface plasmon resonances (LSPR) in adjacent metal disks corrugated with subwavelength spiral patterns. We show that the hybridization results in the splitting of spoof plasmon modes into bonding and antibonding resonances analogous to molecular orbital rule and plasmonic hybridization in optical spectrum. These hybrid modes can be manipulated to produce enormous field enhancements (larger than 5000) by tuning the separation between disks or alte...

  18. Medicago truncatula and Glomus intraradices gene expression in cortical cells harboring arbuscules in the arbuscular mycorrhizal symbiosis

    Directory of Open Access Journals (Sweden)

    Tang Yuhong

    2009-01-01

    Full Text Available Abstract Background Most vascular flowering plants have the capacity to form symbiotic associations with arbuscular mycorrhizal (AM fungi. The symbiosis develops in the roots where AM fungi colonize the root cortex and form arbuscules within the cortical cells. Arbuscules are enveloped in a novel plant membrane and their establishment requires the coordinated cellular activities of both symbiotic partners. The arbuscule-cortical cell interface is the primary functional interface of the symbiosis and is of central importance in nutrient exchange. To determine the molecular events the underlie arbuscule development and function, it is first necessary to identify genes that may play a role in this process. Toward this goal we used the Affymetrix GeneChip® Medicago Genome Array to document the M. truncatula transcript profiles associated with AM symbiosis, and then developed laser microdissection (LM of M. truncatula root cortical cells to enable analyses of gene expression in individual cell types by RT-PCR. Results This approach led to the identification of novel M. truncatula and G. intraradices genes expressed in colonized cortical cells and in arbuscules. Within the arbuscule, expression of genes associated with the urea cycle, amino acid biosynthesis and cellular autophagy was detected. Analysis of gene expression in the colonized cortical cell revealed up-regulation of a lysine motif (LysM-receptor like kinase, members of the GRAS transcription factor family and a symbiosis-specific ammonium transporter that is a likely candidate for mediating ammonium transport in the AM symbiosis. Conclusion Transcript profiling using the Affymetrix GeneChip® Medicago Genome Array provided new insights into gene expression in M. truncatula roots during AM symbiosis and revealed the existence of several G. intraradices genes on the M. truncatula GeneChip®. A laser microdissection protocol that incorporates low-melting temperature Steedman's wax, was

  19. Construction of two genetic linkage maps in cultivated tetraploid alfalfa (Medicago sativa using microsatellite and AFLP markers

    Directory of Open Access Journals (Sweden)

    Santoni Sylvain

    2003-12-01

    Full Text Available Abstract Background Alfalfa (Medicago sativa is a major forage crop. The genetic progress is slow in this legume species because of its autotetraploidy and allogamy. The genetic structure of this species makes the construction of genetic maps difficult. To reach this objective, and to be able to detect QTLs in segregating populations, we used the available codominant microsatellite markers (SSRs, most of them identified in the model legume Medicago truncatula from EST database. A genetic map was constructed with AFLP and SSR markers using specific mapping procedures for autotetraploids. The tetrasomic inheritance was analysed in an alfalfa mapping population. Results We have demonstrated that 80% of primer pairs defined on each side of SSR motifs in M. truncatula EST database amplify with the alfalfa DNA. Using a F1 mapping population of 168 individuals produced from the cross of 2 heterozygous parental plants from Magali and Mercedes cultivars, we obtained 599 AFLP markers and 107 SSR loci. All but 3 SSR loci showed a clear tetrasomic inheritance. For most of the SSR loci, the double-reduction was not significant. For the other loci no specific genotypes were produced, so the significant double-reduction could arise from segregation distortion. For each parent, the genetic map contained 8 groups of four homologous chromosomes. The lengths of the maps were 2649 and 3045 cM, with an average distance of 7.6 and 9.0 cM between markers, for Magali and Mercedes parents, respectively. Using only the SSR markers, we built a composite map covering 709 cM. Conclusions Compared to diploid alfalfa genetic maps, our maps cover about 88–100% of the genome and are close to saturation. The inheritance of the codominant markers (SSR and the pattern of linkage repulsions between markers within each homology group are consistent with the hypothesis of a tetrasomic meiosis in alfalfa. Except for 2 out of 107 SSR markers, we found a similar order of markers on

  20. Genome-wide identification of different dormant Medicago sativa L. MicroRNAs in response to fall dormancy.

    Directory of Open Access Journals (Sweden)

    Wenna Fan

    Full Text Available MicroRNAs (miRNAs are a class of regulatory small RNAs (sRNAs that regulate gene post-transcriptional expression in plants and animals. High-throughput sequencing technology is capable of identifying small RNAs in plant species. Alfalfa (Medicago sativa L. is one of the most widely cultivated perennial forage legumes worldwide, and fall dormancy is an adaptive characteristic related to the biomass production and winter survival in alfalfa. Here, we applied high-throughput sRNA sequencing to identify some miRNAs that were responsive to fall dormancy in standard variety (Maverick and CUF101 of alfalfa.Four sRNA libraries were generated and sequenced from alfalfa leaves in two typical varieties at distinct seasons. Through integrative analysis, we identified 51 novel miRNA candidates of 206 families. Additionally, we identified 28 miRNAs associated with fall dormancy in standard variety (Maverick and CUF101, including 20 known miRNAs and eight novel miRNAs. Both high-throughput sequencing and RT-qPCR confirmed that eight known miRNA members were up-regulated and six known miRNA members were down-regulated in response to fall dormancy in standard variety (Maverick and CUF101. Among the 51 novel miRNA candidates, five miRNAs were up-regulated and three miRNAs were down-regulated in response to fall dormancy in standard variety (Maverick and CUF101, and five of them were confirmed by Northern blot analysis.We identified 20 known miRNAs and eight new miRNA candidates that were responsive to fall dormancy in standard variety (Maverick and CUF101 by high-throughput sequencing of small RNAs from Medicago sativa. Our data provide a useful resource for investigating miRNA-mediated regulatory mechanisms of fall dormancy in alfalfa, and these findings are important for our understanding of the roles played by miRNAs in the response of plants to abiotic stress in general and fall dormancy in alfalfa.

  1. Marine Fish Hybridization

    KAUST Repository

    He, Song

    2017-04-01

    Natural hybridization is reproduction (without artificial influence) between two or more species/populations which are distinguishable from each other by heritable characters. Natural hybridizations among marine fishes were highly underappreciated due to limited research effort; it seems that this phenomenon occurs more often than is commonly recognized. As hybridization plays an important role in biodiversity processes in the marine environment, detecting hybridization events and investigating hybridization is important to understand and protect biodiversity. The first chapter sets the framework for this disseration study. The Cohesion Species Concept was selected as the working definition of a species for this study as it can handle marine fish hybridization events. The concept does not require restrictive species boundaries. A general history and background of natural hybridization in marine fishes is reviewed during in chapter as well. Four marine fish hybridization cases were examed and documented in Chapters 2 to 5. In each case study, at least one diagnostic nuclear marker, screened from among ~14 candidate markers, was found to discriminate the putative hybridizing parent species. To further investigate genetic evidence to support the hybrid status for each hybrid offspring in each case, haploweb analysis on diagnostic markers (nuclear and/or mitochondrial) and the DAPC/PCA analysis on microsatellite data were used. By combining the genetic evidences, morphological traits, and ecological observations together, the potential reasons that triggered each hybridization events and the potential genetic/ecology effects could be discussed. In the last chapter, sequences from 82 pairs of hybridizing parents species (for which COI barcoding sequences were available either on GenBank or in our lab) were collected. By comparing the COI fragment p-distance between each hybridizing parent species, some general questions about marine fish hybridization were discussed: Is

  2. Advances in Study on Bio-Energy Utilization of Stem Cell Wall Components in Alfalfa (Medicago sativa L.)%紫花苜蓿(Medicago sativa L.)生物能源利用的研究进展

    Institute of Scientific and Technical Information of China (English)

    王晓娟; 张树振; 林双双; 邓志刚; 金樑

    2013-01-01

    紫花苜蓿(Medicago sativa L.)适应性强、生物质产量高,茎可用于生产酒精,叶片可用于家畜饲料,是最具开发潜力的能源植物之一.本文从紫花苜蓿生物能源利用角度出发,系统回顾了近年来紫花苜蓿作为能源植物在种质资源评价、细胞壁主要成分(纤维素、半纤维素、木质素)合成途径及其遗传调控以及栽培管理对酒精生产效率的影响等方面的研究进展,重点讨论了苜蓿细胞壁发育和木质素生物合成基因及其调控效应,并 对紫花苜蓿作为能源植物的研发前景进行了展望.

  3. Rhizobium favelukesii sp. nov., isolated from the root nodules of alfalfa (Medicago sativa L).

    Science.gov (United States)

    Torres Tejerizo, Gonzalo; Rogel, Marco Antonio; Ormeño-Orrillo, Ernesto; Althabegoiti, María Julia; Nilsson, Juliet Fernanda; Niehaus, Karsten; Schlüter, Andreas; Pühler, Alfred; Del Papa, María Florencia; Lagares, Antonio; Martínez-Romero, Esperanza; Pistorio, Mariano

    2016-11-01

    Strains LPU83T and Or191 of the genus Rhizobium were isolated from the root nodules of alfalfa, grown in acid soils from Argentina and the USA. These two strains, which shared the same plasmid pattern, lipopolysaccharide profile, insertion-sequence fingerprint, 16S rRNA gene sequence and PCR-fingerprinting pattern, were different from reference strains representing species of the genus Rhizobium with validly published names. On the basis of previously reported data and from new DNA-DNA hybridization results, phenotypic characterization and phylogenetic analyses, strains LPU83T and Or191 can be considered to be representatives of a novel species of the genus Rhizobium, for which the name Rhizobium favelukesii sp. nov. is proposed. The type strain of this species is LPU83T (=CECT 9014T=LMG 29160T), for which an improved draft-genome sequence is available.

  4. Oxytetracycline Toxicity and its Effect on Phytoremediation by Sedum Plumbizincicola and Medicago Sativa in Metal Contaminated Soil.

    Science.gov (United States)

    Ma, Tingting; Zhou, Liqiang; Chen, Li 'ke; Li, Zhu; Wu, Longhua; Christie, Peter; Luo, Yongming

    2016-10-05

    Excessive use of antibiotics potentially threatens human health, agricultural production and soil phytoremediation. This arouses concern over the potential adverse effects of a commonly used antibiotic, oxytetracycline (OTC), on plants used for soil remediation and possible stimulation of antibiotic resistance genes in soils. A greenhouse experiment was conducted to investigate different rates (0, 1, 5, and 25 mg kg-1) and frequencies (one single high and daily low application) of OTC addition to soil on phytoremediation of a heavy metal contaminated soil by Sedum plumbizincicola and/or Medicago sativa (alfalfa). After 90 days both Cd and Zn were substantially removed by phytoextraction into S. plumbizincicola shoots especially at the high OTC (25 mg kg-1) treatment which also led to inhibition of anti-oxidative enzyme activities in both plant species. Soil microbial activity decreased significantly with the addition of OTC and this was ameliorated by planting alfalfa and S. plumbizincicola together. OTC at Alfalfa exhibited greater detoxification ability and effectiveness in soil microbial activity promotion than S. plumbizincicola with intercropping. Phytoremediation by alfalfa and S. plumbizincicola in association can both promote the removal of heavy metals and also alleviate the toxic effects of pollutants to plants and soil microbes even at relatively high soil OTC concentrations.

  5. Effects of compost organic amendments on chemical composition and in vitro digestibility of alfalfa (Medicago sativa L.

    Directory of Open Access Journals (Sweden)

    Francesco Montemurro

    2010-01-01

    Full Text Available The following fertiliser treatments were compared during the years 2002 and 2003 on alfalfa forage (Medicago sativa L.: compost obtained from the organic fraction of the Municipal Solid Waste (MSW; olive pomace compost (OPC; mineral fertiliser (Min. All the treatments allowed a distribution of 75kg ha-1 of P2O5. Three cuttings occurred: at 168, 206 and 351 days after compost application (DAA in 2002; 119, 152 and 320 DAA in 2003. Cumulative biomass and dry matter yields were measured during each experimental year. Furthermore, chemical composition and in vitro digestibility of dry matter (DMd, organic matter (OMd, crude protein (CPd and NDF (NDFd were determined. MSW treatment showed a significantly (P<0.01 higher content of ADL than OPC and Min (77.0, 66.0 and 65.0g kg-1 DM, respectively. Fertiliser treatments also affected (P<0.01 digestibility parameters. In fact, DMd and OMd values showed the same trend with lower percentages in MSW treatment than in the OPC and Min ones. The NDFd differed in all treatments having the highest value in OPC (40.1%. The results indicated that the soil distribution of organic materials offer the possibility to reduce the application of mineral fertilisers and production costs without decreasing alfalfa yield, forage chemical composition and in vitro digestibility.

  6. The Medicago truncatula Sucrose Transporter Family: Characterization and Implication of Key Members in Carbon Partitioning towards Arbuscular Mycorrhizal Fungi

    Institute of Scientific and Technical Information of China (English)

    Joan Doidy; Diederik van Tuinen; Olivier Lamotte; Marion Corneillat; Gérard Alcaraz; Daniel Wipf

    2012-01-01

    We identified de novo sucrose transporter (SUT) genes involved in long-distance transport of sucrose from photosynthetic source leaves towards sink organs in the model leguminous species Medicago truncatula.The identification and functional analysis of sugar transporters provide key information on mechanisms that underlie carbon partitioning in plant-microorganism interactions.In that way,full-length sequences of the M.truncatula SUT (MtSUT)family were retrieved and biochemical characterization of MtSUT members was performed by heterologous expression in yeast.The MtSUT family now comprises six genes which distribute among Dicotyledonous clades.MtSUT1-1 and MtSUT4-1 are key members in regard to their expression profiles in source leaves and sink roots and were characterized as functional H+/sucrose transporters.Physiological and molecular responses to phosphorus supply and inoculation by the arbuscular mycorrhizal fungus (AMF) Glomus intraradices was studied by gene expression and sugar quantification analyses.Sucrose represents the main sugar transport form in M.truncatula and the expression profiles of MtSUT1-1,MtSUT2,and MtSUT4-1 highlight a fine-tuning regulation for beneficial sugar fluxes towards the fungal symbiont.Taken together,these results suggest distinct functions for proteins from the SUT1,SUT2,and SUT4 clades in plant and in biotrophic interactions.

  7. NFP, a LysM protein controlling Nod factor perception, also intervenes in Medicago truncatula resistance to pathogens.

    Science.gov (United States)

    Rey, Thomas; Nars, Amaury; Bonhomme, Maxime; Bottin, Arnaud; Huguet, Stéphanie; Balzergue, Sandrine; Jardinaud, Marie-Françoise; Bono, Jean-Jacques; Cullimore, Julie; Dumas, Bernard; Gough, Clare; Jacquet, Christophe

    2013-05-01

    Plant LysM proteins control the perception of microbial-derived N-acetylglucosamine compounds for the establishment of symbiosis or activation of plant immunity. This raises questions about how plants, and notably legumes, can differentiate friends and foes using similar molecular actors and whether any receptors can intervene in both symbiosis and resistance. To study this question, nfp and lyk3 LysM-receptor like kinase mutants of Medicago truncatula that are affected in the early steps of nodulation, were analysed following inoculation with Aphanomyces euteiches, a root oomycete. The role of NFP in this interaction was further analysed by overexpression of NFP and by transcriptome analyses. nfp, but not lyk3, mutants were significantly more susceptible than wildtype plants to A. euteiches, whereas NFP overexpression increased resistance. Transcriptome analyses on A. euteiches inoculation showed that mutation in the NFP gene led to significant changes in the expression of c. 500 genes, notably involved in cell dynamic processes previously associated with resistance to pathogen penetration. nfp mutants also showed an increased susceptibility to the fungus Colletotrichum trifolii. These results demonstrate that NFP intervenes in M. truncatula immunity, suggesting an unsuspected role for NFP in the perception of pathogenic signals. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  8. Flavonoids and Auxin Transport Inhibitors Rescue Symbiotic Nodulation in the Medicago truncatula Cytokinin Perception Mutant cre1.

    Science.gov (United States)

    Ng, Jason Liang Pin; Hassan, Samira; Truong, Thy T; Hocart, Charles H; Laffont, Carole; Frugier, Florian; Mathesius, Ulrike

    2015-08-01

    Initiation of symbiotic nodules in legumes requires cytokinin signaling, but its mechanism of action is largely unknown. Here, we tested whether the failure to initiate nodules in the Medicago truncatula cytokinin perception mutant cre1 (cytokinin response1) is due to its altered ability to regulate auxin transport, auxin accumulation, and induction of flavonoids. We found that in the cre1 mutant, symbiotic rhizobia cannot locally alter acro- and basipetal auxin transport during nodule initiation and that these mutants show reduced auxin (indole-3-acetic acid) accumulation and auxin responses compared with the wild type. Quantification of flavonoids, which can act as endogenous auxin transport inhibitors, showed a deficiency in the induction of free naringenin, isoliquiritigenin, quercetin, and hesperetin in cre1 roots compared with wild-type roots 24 h after inoculation with rhizobia. Coinoculation of roots with rhizobia and the flavonoids naringenin, isoliquiritigenin, and kaempferol, or with the synthetic auxin transport inhibitor 2,3,5,-triiodobenzoic acid, rescued nodulation efficiency in cre1 mutants and allowed auxin transport control in response to rhizobia. Our results suggest that CRE1-dependent cytokinin signaling leads to nodule initiation through the regulation of flavonoid accumulation required for local alteration of polar auxin transport and subsequent auxin accumulation in cortical cells during the early stages of nodulation.

  9. Genetic Mapping of a Major Resistance Gene to Pea Aphid (Acyrthosipon pisum in the Model Legume Medicago truncatula

    Directory of Open Access Journals (Sweden)

    Lars G. Kamphuis

    2016-07-01

    Full Text Available Resistance to the Australian pea aphid (PA; Acyrthosiphon pisum biotype in cultivar Jester of the model legume Medicago truncatula is mediated by a single dominant gene and is phloem-mediated. The genetic map position for this resistance gene, APR (Acyrthosiphon pisum resistance, is provided and shows that APR maps 39 centiMorgans (cM distal of the A. kondoi resistance (AKR locus, which mediates resistance to a closely related species of the same genus bluegreen aphid (A. kondoi. The APR region on chromosome 3 is dense in classical nucleotide binding site leucine-rich repeats (NLRs and overlaps with the region harbouring the RAP1 gene which confers resistance to a European PA biotype in the accession Jemalong A17. Further screening of a core collection of M. truncatula accessions identified seven lines with strong resistance to PA. Allelism experiments showed that the single dominant resistance to PA in M. truncatula accessions SA10481 and SA1516 are allelic to SA10733, the donor of the APR locus in cultivar Jester. While it remains unclear whether there are multiple PA resistance genes in an R-gene cluster or the resistance loci identified in the other M. truncatula accessions are allelic to APR, the introgression of APR into current M. truncatula cultivars will provide more durable resistance to PA.

  10. Adjustment of host cells for accommodation of symbiotic bacteria: vacuole defunctionalization, HOPS suppression, and TIP1g retargeting in Medicago.

    Science.gov (United States)

    Gavrin, Aleksandr; Kaiser, Brent N; Geiger, Dietmar; Tyerman, Stephen D; Wen, Zhengyu; Bisseling, Ton; Fedorova, Elena E

    2014-09-01

    In legume-rhizobia symbioses, the bacteria in infected cells are enclosed in a plant membrane, forming organelle-like compartments called symbiosomes. Symbiosomes remain as individual units and avoid fusion with lytic vacuoles of host cells. We observed changes in the vacuole volume of infected cells and thus hypothesized that microsymbionts may cause modifications in vacuole formation or function. To examine this, we quantified the volumes and surface areas of plant cells, vacuoles, and symbiosomes in root nodules of Medicago truncatula and analyzed the expression and localization of VPS11 and VPS39, members of the HOPS vacuole-tethering complex. During the maturation of symbiosomes to become N2-fixing organelles, a developmental switch occurs and changes in vacuole features are induced. For example, we found that expression of VPS11 and VPS39 in infected cells is suppressed and host cell vacuoles contract, permitting the expansion of symbiosomes. Trafficking of tonoplast-targeted proteins in infected symbiotic cells is also altered, as shown by retargeting of the aquaporin TIP1g from the tonoplast membrane to the symbiosome membrane. This retargeting appears to be essential for the maturation of symbiosomes. We propose that these alterations in the function of the vacuole are key events in the adaptation of the plant cell to host intracellular symbiotic bacteria. © 2014 American Society of Plant Biologists. All rights reserved.

  11. Jasmonate Signalling and Defence Responses in the Model Legume Medicago truncatula—A Focus on Responses to Fusarium Wilt Disease

    Science.gov (United States)

    Thatcher, Louise F.; Gao, Ling-Ling; Singh, Karam B.

    2016-01-01

    Jasmonate (JA)-mediated defences play important roles in host responses to pathogen attack, in particular to necrotrophic fungal pathogens that kill host cells in order to extract nutrients and live off the dead plant tissue. The root-infecting fungal pathogen Fusarium oxysporum initiates a necrotrophic growth phase towards the later stages of its lifecycle and is responsible for devastating Fusarium wilt disease on numerous legume crops worldwide. Here we describe the use of the model legume Medicago truncatula to study legume–F. oxysporum interactions and compare and contrast this against knowledge from other model pathosystems, in particular Arabidopsis thaliana–F. oxysporum interactions. We describe publically-available genomic, transcriptomic and genetic (mutant) resources developed in M. truncatula that enable dissection of host jasmonate responses and apply aspects of these herein during the M. truncatula-–F. oxysporum interaction. Our initial results suggest not all components of JA-responses observed in M. truncatula are shared with Arabidopsis in response to F. oxysporum infection. PMID:27135231

  12. Jasmonate Signalling and Defence Responses in the Model Legume Medicago truncatula-A Focus on Responses to Fusarium Wilt Disease.

    Science.gov (United States)

    Thatcher, Louise F; Gao, Ling-Ling; Singh, Karam B

    2016-02-05

    Jasmonate (JA)-mediated defences play important roles in host responses to pathogen attack, in particular to necrotrophic fungal pathogens that kill host cells in order to extract nutrients and live off the dead plant tissue. The root-infecting fungal pathogen Fusarium oxysporum initiates a necrotrophic growth phase towards the later stages of its lifecycle and is responsible for devastating Fusarium wilt disease on numerous legume crops worldwide. Here we describe the use of the model legume Medicago truncatula to study legume-F. oxysporum interactions and compare and contrast this against knowledge from other model pathosystems, in particular Arabidopsis thaliana-F. oxysporum interactions. We describe publically-available genomic, transcriptomic and genetic (mutant) resources developed in M. truncatula that enable dissection of host jasmonate responses and apply aspects of these herein during the M. truncatula--F. oxysporum interaction. Our initial results suggest not all components of JA-responses observed in M. truncatula are shared with Arabidopsis in response to F. oxysporum infection.

  13. Alfalfa (Medicago sativa L.) shoot saponins: identification and bio-activity by the assessment of aphid feeding.

    Science.gov (United States)

    Mazahery-Laghab, H; Yazdi-Samadi, B; Bagheri, M; Bagheri, A R

    2011-01-01

    Biochemical components in alfalfa (Medicago sativa L.), such as saponins, can act as protecting factors against bio-stresses. Saponins are also antifeedants and show oral toxicity towards higher and lower animals. Changes in saponins, such as variation in the carbon skeleton, or hydrolysis of saponin glycosides and other conjugates, may change their biological effects. The aims of this research were to study saponin variation in different growth stages of alfalfa and to investigate the biological role of saponins in the spotted alfalfa aphid, Therioaphis maculata. Saponins from alfalfa shoots in different growth stages were extracted, chemically purified and analysed by TLC. Specific saponins such as soyasaponin1 from root and shoot and two bisdesmosides of medicagenic acid, one from shoot and another from root tissues, were identified using reference compounds allowing changes in saponin composition during plant development in different shoot tissues of alfalfa to be assessed. The response of the alfalfa aphid to feeding on alfalfa in different growth stages was studied. No significant difference in the survival of aphids, from neonate to adult, was observed, but due to the antibiotic effects of saponins, two differences were found in the onset of nymph production and cumulative nymph production. The results show that the saponin composition in alfalfa changes with plant development and this, in turn, can often negatively affect the development of specific insect pests such as the spotted alfalfa aphid, suggesting a possible biological role of alfalfa saponins.

  14. In vitro and in vivo antioxidant activity of alfalfa (Medicago sativa L.) on carbon tetrachloride intoxicated rats.

    Science.gov (United States)

    Al-Dosari, Mohammed S

    2012-01-01

    The present study was conducted to determine whether lyophilized aqueous extract of alfalfa, or Medicago sativa L. could exert antioxidant activity against carbon tetrachloride-induced oxidative stress and liver injury in rats. The hepatoprotective activity of alfalfa extract was determined by assessing the levels of serum transaminases, ALP, bilirubin and lipid profile. Further, the effect of the test substance on malondialdehyde (MDA), an end product of lipid peroxidation; antioxidant liver enzyme non-protein sulfhydryl (NP-SH); and total protein (TP) were also studied. Serum transaminase, ALP, bilirubin level, lipid profile and liver MDA were significantly elevated and the antioxidant status in liver NP-SH and TP contents were declined in animals treated with CCl (4) alone. Pretreatment with alfalfa and silymarin for three weeks prior to the administration of CCl (4) significantly prevented the increase in the serum levels of hepatic marker, LDL, VLDL levels enzymes and reduced oxidative stress indicated by elevated NP-SH and TP concentration. The histopathological examination of the livers also showed that the alfalfa extract reduced the incidence of liver lesions induced by CCl (4). The in vitro antioxidant assessment of alfalfa extract on DPPH and carotene-linoleic assays demonstrated a moderate antioxidant potential. Results suggest that the alfalfa extract possesses hepatoprotective and antioxidative stress properties possibly through its antioxidant phytochemical constituents and substantiates its use in various liver disorders as a hepatoprotector.

  15. Low-fiber alfalfa (Medicago sativa L.) meal in the laying hen diet: effects on productive traits and egg quality.

    Science.gov (United States)

    Laudadio, V; Ceci, E; Lastella, N M B; Introna, M; Tufarelli, V

    2014-07-01

    This study was designed to determine the effects on laying performance and egg quality resulting from partial substitution of soybean meal (SBM) with low-fiber alfalfa (LFA; Medicago sativa L.) meal in the diet of early-phase laying hens. ISA Brown layers, 18 wk of age, were randomly allocated to 2 dietary treatments and fed for 10 wk. The hens were fed 2 wheat middling-based diets: a control diet, which contained SBM (15% of diet), and a test diet containing LFA (15% of diet) as the main protein source. Low-fiber alfalfa meal was obtained by a combination of sieving and air-classification processes. Feed intake was recorded daily, and egg production was calculated on a hen-day basis; eggs from each group were weekly collected to evaluate egg components and quality. The partial substitution of SBM with LFA had no adverse effect on growth performance of early-phase laying hens. Egg production and none of the egg-quality traits examined were influenced by dietary treatment, except for yolk color (P alfalfa meal in the laying-hen diet can positively influence yolk quality without adversely affecting productive traits. © 2014 Poultry Science Association Inc.

  16. Salicornia europaea L. Na⁺/H⁺ antiporter gene improves salt tolerance in transgenic alfalfa (Medicago sativa L.).

    Science.gov (United States)

    Zhang, L Q; Niu, Y D; Huridu, H; Hao, J F; Qi, Z; Hasi, A

    2014-07-24

    In order to obtain a salt-tolerant perennial alfalfa (Medicago sativa L.), we transferred the halophyte Salicornia europaea L. Na(+)/H(+) antiporter gene, SeNHX1, to alfalfa by using the Agrobacterium-mediated transformation method. The transformants were confirmed by both PCR and RT-PCR analyses. Of 197 plants that were obtained after transformation, 36 were positive by PCR analysis using 2 primer pairs for the CaMV35S-SeNHX1 and SeNHX1-Nos fragments; 6 plants survived in a greenhouse. RT-PCR analysis revealed that SeNHX1 was expressed in 5 plants. The resultant transgenic alfalfa had better salt tolerance. After stress treatment for 21 days with 0.6% NaCl, the chlorophyll and MDA contents in transgenic plants were lower, but proline content and SOD, POD, and CAT activities were higher than those in wild-type plants. These results suggest that the salt tolerance of transgenic alfalfa was improved by the overexpression of the SeNHX1 gene.

  17. Characterization of two novel cold-inducible K3 dehydrin genes from alfalfa (Medicago sativa spp. sativa L.).

    Science.gov (United States)

    Dubé, Marie-Pier; Castonguay, Yves; Cloutier, Jean; Michaud, Josée; Bertrand, Annick

    2013-03-01

    Dehydrin defines a complex family of intrinsically disordered proteins with potential adaptive value with regard to freeze-induced cell dehydration. Search within an expressed sequence tags library from cDNAs of cold-acclimated crowns of alfalfa (Medicago sativa spp. sativa L.) identified transcripts putatively encoding K(3)-type dehydrins. Analysis of full-length coding sequences unveiled two highly homologous sequence variants, K(3)-A and K(3)-B. An increase in the frequency of genotypes yielding positive genomic amplification of the K(3)-dehydrin variants in response to selection for superior tolerance to freezing and the induction of their expression at low temperature strongly support a link with cold adaptation. The presence of multiple allelic forms within single genotypes and independent segregation indicate that the two K(3) dehydrin variants are encoded by distinct genes located at unlinked loci. The co-inheritance of the K(3)-A dehydrin with a Y(2)K(4) dehydrin restriction fragment length polymorphism with a demonstrated impact on freezing tolerance suggests the presence of a genome domain where these functionally related genes are located. These results provide additional evidence that dehydrin play important roles with regard to tolerance to subfreezing temperatures. They also underscore the value of recurrent selection to help identify variants within a large multigene family in allopolyploid species like alfalfa.

  18. Soil bulk electrical resistivity and forage ground cover: nonlinear models in an alfalfa (Medicago sativa L. case study

    Directory of Open Access Journals (Sweden)

    Roberta Rossi

    2015-12-01

    Full Text Available Alfalfa is a highly productive and fertility-building forage crop; its performance, can be highly variable as influenced by within-field soil spatial variability. Characterising the relations between soil and forage- variation is important for optimal management. The aim of this work was to model the relationship between soil electrical resistivity (ER and plant productivity in an alfalfa (Medicago sativa L. field in Southern Italy. ER mapping was accomplished by a multi-depth automatic resistivity profiler. Plant productivity was assessed through normalised difference vegetation index (NDVI at 2 dates. A non-linear relationship between NDVI and deep soil ER was modelled within the framework of generalised additive models. The best model explained 70% of the total variability. Soil profiles at six locations selected along a gradient of ER showed differences related to texture (ranging from clay to sandy-clay loam, gravel content (0 to 55% and to the presence of a petrocalcic horizon. Our results prove that multi-depth ER can be used to localise permanent soil features that drive plant productivity.

  19. Cytotoxicity and apoptosis induced by alfalfa (Medicago sativa) leaf extracts in sensitive and multidrug-resistant tumor cells.

    Science.gov (United States)

    Gatouillat, Grégory; Magid, Abdulmagid Alabdul; Bertin, Eric; Okiemy-Akeli, Marie-Genevieve; Morjani, Hamid; Lavaud, Catherine; Madoulet, Claudie

    2014-01-01

    Alfalfa (Medicago sativa) has been used to cure a wide variety of ailments. However, only a few studies have reported its anticancer effects. In this study, extracts were obtained from alfalfa leaves and their cytotoxic effects were assessed on several sensitive and multidrug-resistant tumor cells lines. Using the mouse leukaemia P388 cell line and its doxorubicin-resistant counterpart (P388/DOX), we showed that the inhibition of cell growth induced by alfalfa leaf extracts was mediated through the induction of apoptosis, as evidenced by DNA fragmentation analysis. The execution of programmed cell death was achieved via the activation of caspase-3, leading to PARP cleavage. Fractionation of toluene extract (To-1), the most active extract obtained from crude extract, led to the identification of 3 terpene derivatives and 5 flavonoids. Among them, (-)-medicarpin, (-)-melilotocarpan E, millepurpan, tricin, and chrysoeriol showed cytotoxic effects in P388 as well as P388/DOX cells. These results demonstrate that alfalfa leaf extract may have interesting potential in cancer chemoprevention and therapy.

  20. Toxic effects of copper-based nanoparticles or compounds to lettuce (Lactuca sativa) and alfalfa (Medicago sativa).

    Science.gov (United States)

    Hong, Jie; Rico, Cyren M; Zhao, Lijuan; Adeleye, Adeyemi S; Keller, Arturo A; Peralta-Videa, Jose R; Gardea-Torresdey, Jorge L

    2015-01-01

    The increased production and use of nanoparticles (NPs) has generated concerns about their impact on living organisms. In this study, nCu, bulk Cu, nCuO, bulk CuO, Cu(OH)2 (CuPRO 2005, Kocide 3000), and CuCl2 were exposed for 15 days to 10 days-old hydroponically grown lettuce (Lactuca sativa) and alfalfa (Medicago sativa). Each compound was applied at 0, 5, 10, and 20 mg L(-1). At harvest, we measured the size of the plants and determined the concentration of Cu, macro and microelements by using ICP-OES. Catalase and ascorbate peroxidase activity was also determined. Results showed that all Cu NPs/compounds reduced the root length by 49% in both plant species. All Cu NPs/compounds increased Cu, P, and S (>100%, >50%, and >20%, respectively) in alfalfa shoots and decreased P and Fe in lettuce shoot (>50% and >50%, respectively, excluding Fe in CuCl2 treatment). Biochemical assays showed reduced catalase activity in alfalfa (root and shoot) and increased ascorbate peroxidase activity in roots of both plant species. Results suggest that Cu NPs/compounds not only reduced the size of the plants but altered nutrient content and enzyme activity in both plant species.

  1. Identification of molecular markers associated with Verticillium wilt resistance in alfalfa (Medicago sativa L.) using high-resolution melting.

    Science.gov (United States)

    Zhang, Tiejun; Yu, Long-Xi; McCord, Per; Miller, David; Bhamidimarri, Suresh; Johnson, David; Monteros, Maria J; Ho, Julie; Reisen, Peter; Samac, Deborah A

    2014-01-01

    Verticillium wilt, caused by the soilborne fungus, Verticillium alfalfae, is one of the most serious diseases of alfalfa (Medicago sativa L.) worldwide. To identify loci associated with resistance to Verticillium wilt, a bulk segregant analysis was conducted in susceptible or resistant pools constructed from 13 synthetic alfalfa populations, followed by association mapping in two F1 populations consisted of 352 individuals. Simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) markers were used for genotyping. Phenotyping was done by manual inoculation of the pathogen to replicated cloned plants of each individual and disease severity was scored using a standard scale. Marker-trait association was analyzed by TASSEL. Seventeen SNP markers significantly associated with Verticillium wilt resistance were identified and they were located on chromosomes 1, 2, 4, 7 and 8. SNP markers identified on chromosomes 2, 4 and 7 co-locate with regions of Verticillium wilt resistance loci reported in M. truncatula. Additional markers identified on chromosomes 1 and 8 located the regions where no Verticillium resistance locus has been reported. This study highlights the value of SNP genotyping by high resolution melting to identify the disease resistance loci in tetraploid alfalfa. With further validation, the markers identified in this study could be used for improving resistance to Verticillium wilt in alfalfa breeding programs.

  2. Metabolite profiling of triterpene saponins in Medicago truncatula hairy roots by liquid chromatography Fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Pollier, Jacob; Morreel, Kris; Geelen, Danny; Goossens, Alain

    2011-06-24

    Triterpenes are one of the largest classes of plant natural products, with an enormous variety in structure and bioactivities. Here, triterpene saponins from hairy roots of the model legume Medicago truncatula were profiled with reversed-phase liquid chromatography coupled to negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (LC ESI FT-ICR MS). Owing to the accuracy of the FT-ICR MS, reliable molecular formulas of the detected compounds could be predicted, which, together with the generated MS(n) spectra, allowed the tentative identification of 79 different saponins, of which 61 had not been detected previously in M. truncatula. Upon collision-induced dissociation of saponins that contain a uronic acid residue in the sugar chain, fragment ions resulting from cross-ring cleavages of the uronic acid residues were observed. The identified saponins are glycosides of 10 different sapogenins, of which three were not detected before in M. truncatula. Zanhic acid glycosides, which are prevalent in the aerial parts of M. truncatula, were absent in the hairy root extracts. This metabolite compendium will facilitate future functional genomic studies of triterpene saponin biosynthesis in M. truncatula.

  3. Genome-Wide Identification and Expression Analysis of the 14-3-3 Family Genes in Medicago truncatula

    Directory of Open Access Journals (Sweden)

    Cheng eQin

    2016-03-01

    Full Text Available The 14-3-3 gene family, which is conserved in eukaryotes, is involved in protein-protein interactions and mediates signal transduction. However, detailed investigations of the 14-3-3 gene family in Medicago truncatula are largely unknown. In this study, the identification and study of M. truncatula 14-3-3-family genes were performed based on the latest M. truncatula genome. In the M. truncatula genome, 10 14-3-3 family genes were identified, and they can be grouped into ε and non-ε groups. An exon-intron analysis showed that the gene structures are conserved in the same group. The protein structure analysis showed that 14-3-3 proteins in M. truncatula are composed of nine typical antiparallel α-helices. The expression patterns of Mt14-3-3 genes indicated that they are expressed in all tissues. Furthermore, the gene expression levels of Mt14-3-3 under hormone treatment and Sinorhizobium meliloti infection showed that the Mt14-3-3 genes were involve in nodule formation. Our findings lay a solid foundation for further functional studies of 14-3-3 in M. truncatula.

  4. Sinorhizobium meliloti Controls Nitric Oxide-Mediated Post-Translational Modification of a Medicago truncatula Nodule Protein.

    Science.gov (United States)

    Blanquet, Pauline; Silva, Liliana; Catrice, Olivier; Bruand, Claude; Carvalho, Helena; Meilhoc, Eliane

    2015-12-01

    Nitric oxide (NO) is involved in various plant-microbe interactions. In the symbiosis between soil bacterium Sinorhizobium meliloti and model legume Medicago truncatula, NO is required for an optimal establishment of the interaction but is also a signal for nodule senescence. Little is known about the molecular mechanisms responsible for NO effects in the legume-rhizobium interaction. Here, we investigate the contribution of the bacterial NO response to the modulation of a plant protein post-translational modification in nitrogen-fixing nodules. We made use of different bacterial mutants to finely modulate NO levels inside M. truncatula root nodules and to examine the consequence on tyrosine nitration of the plant glutamine synthetase, a protein responsible for assimilation of the ammonia released by nitrogen fixation. Our results reveal that S. meliloti possesses several proteins that limit inactivation of plant enzyme activity via NO-mediated post-translational modifications. This is the first demonstration that rhizobia can impact the course of nitrogen fixation by modulating the activity of a plant protein.

  5. Architecture of infection thread networks in developing root nodules induced by the symbiotic bacterium Sinorhizobium meliloti on Medicago truncatula.

    Science.gov (United States)

    Monahan-Giovanelli, Hannah; Pinedo, Catalina Arango; Gage, Daniel J

    2006-02-01

    During the course of the development of nitrogen-fixing root nodules induced by Sinorhizobium meliloti on the model plant Medicago truncatula, tubules called infection threads are cooperatively constructed to deliver the bacterial symbiont from the root surface to cells in the interior of the root and developing nodule. Three-dimensional reconstructions of infection threads inside M. truncatula nodules showed that the threads formed relatively simple, tree-like networks. Some characteristics of thread networks, such as branch length, branch density, and branch surface-to-volume ratios, were remarkably constant across nodules in different stages of development. The overall direction of growth of the networks changed as nodules developed. In 5-d-old nodules, the overall growth of the network was directed inward toward the root. However, well-defined regions of these young networks displayed an outward growth bias, indicating that they were likely in the process of repolarizing their direction of development in response to the formation of the outward-growing nodule meristem. In 10- and 30-d-old nodules, the branches of the network grew outward toward the meristem and away from the roots on which the nodules developed.

  6. Involvement of abscisic acid in the response of Medicago sativa plants in symbiosis with Sinorhizobium meliloti to salinity.

    Science.gov (United States)

    Palma, F; López-Gómez, M; Tejera, N A; Lluch, C

    2014-06-01

    Legumes are classified as salt-sensitive crops with their productivity particularly affected by salinity. Abcisic acid (ABA) plays an important role in the response to environmental stresses as signal molecule which led us to study its role in the response of nitrogen fixation and antioxidant metabolism in root nodules of Medicago sativa under salt stress conditions. Adult plants inoculated with Sinorhizobium meliloti were treated with 1 μM and 10 μM ABA two days before 200 mM salt addition. Exogenous ABA together with the salt treatment provoked a strong induction of the ABA content in the nodular tissue which alleviated the inhibition induced by salinity in the plant growth and nitrogen fixation. Antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) were induced by ABA pre-treatments under salt stress conditions which together with the reduction of the lipid peroxidation, suggest a role for ABA as signal molecule in the activation of the nodular antioxidant metabolism. Interaction between ABA and polyamines (PAs), described as anti-stress molecules, was studied being detected an induction of the common polyamines spermidine (Spd) and spermine (Spm) levels by ABA under salt stress conditions. In conclusion, ABA pre-treatment improved the nitrogen fixation capacity under salt stress conditions by the induction of the nodular antioxidant defenses which may be mediated by the common PAs Spd and Spm that seems to be involved in the anti-stress response induced by ABA.

  7. The Medicago truncatula CRE1 cytokinin receptor regulates lateral root development and early symbiotic interaction with Sinorhizobium meliloti.

    Science.gov (United States)

    Gonzalez-Rizzo, Silvina; Crespi, Martin; Frugier, Florian

    2006-10-01

    Legumes develop different types of lateral organs from their primary root, lateral roots and nodules, the latter depending on a symbiotic interaction with Sinorhizobium meliloti. Phytohormones have been shown to function in the control of these organogeneses. However, related signaling pathways have not been identified in legumes. We cloned and characterized the expression of Medicago truncatula genes encoding members of cytokinin signaling pathways. RNA interference of the cytokinin receptor homolog Cytokinin Response1 (Mt CRE1) led to cytokinin-insensitive roots, which showed an increased number of lateral roots and a strong reduction in nodulation. Both the progression of S. meliloti infection and nodule primordia formation were affected. We also identified two cytokinin signaling response regulator genes, Mt RR1 and Mt RR4, which are induced early during the symbiotic interaction. Induction of these genes by S. meliloti infection is altered in mutants affected in the Nod factor signaling pathway; conversely, cytokinin regulation of the early nodulin Nodule Inception1 (Mt NIN) depends on Mt CRE1. Hence, cytokinin signaling mediated by a single receptor, Mt CRE1, leads to an opposite control of symbiotic nodule and lateral root organogenesis. Mt NIN, Mt RR1, and Mt RR4 define a common pathway activated during early S. meliloti interaction, allowing crosstalk between plant cytokinins and bacterial Nod factors signals.

  8. Plant-activated bacterial receptor adenylate cyclases modulate epidermal infection in the Sinorhizobium meliloti-Medicago symbiosis.

    Science.gov (United States)

    Tian, Chang Fu; Garnerone, Anne-Marie; Mathieu-Demazière, Céline; Masson-Boivin, Catherine; Batut, Jacques

    2012-04-24

    Legumes and soil bacteria called rhizobia have coevolved a facultative nitrogen-fixing symbiosis. Establishment of the symbiosis requires bacterial entry via root hair infection threads and, in parallel, organogenesis of nodules that subsequently are invaded by bacteria. Tight control of nodulation and infection is required to maintain the mutualistic character of the interaction. Available evidence supports a passive bacterial role in nodulation and infection after the microsymbiont has triggered the symbiotic plant developmental program. Here we identify in Sinorhizobium meliloti, the Medicago symbiont, a cAMP-signaling regulatory cascade consisting of three receptor-like adenylate cyclases, a Crp-like regulator, and a target gene of unknown function. The cascade is activated specifically by a plant signal during nodule organogenesis. Cascade inactivation results in a hyperinfection phenotype consisting of abortive epidermal infection events uncoupled from nodulation. These findings show that, in response to a plant signal, rhizobia play an active role in the control of infection. We suggest that rhizobia may modulate the plant's susceptibility to infection. This regulatory loop likely aims at optimizing legume infection.

  9. (Homo)glutathione depletion modulates host gene expression during the symbiotic interaction between Medicago truncatula and Sinorhizobium meliloti.

    Science.gov (United States)

    Pucciariello, Chiara; Innocenti, Gilles; Van de Velde, Willem; Lambert, Annie; Hopkins, Julie; Clément, Mathilde; Ponchet, Michel; Pauly, Nicolas; Goormachtig, Sofie; Holsters, Marcelle; Puppo, Alain; Frendo, Pierre

    2009-11-01

    Under nitrogen-limiting conditions, legumes interact with symbiotic rhizobia to produce nitrogen-fixing root nodules. We have previously shown that glutathione and homoglutathione [(h)GSH] deficiencies impaired Medicago truncatula symbiosis efficiency, showing the importance of the low M(r) thiols during the nodulation process in the model legume M. truncatula. In this study, the plant transcriptomic response to Sinorhizobium meliloti infection under (h)GSH depletion was investigated using cDNA-amplified fragment length polymorphism analysis. Among 6,149 expression tags monitored, 181 genes displayed significant differential expression between inoculated control and inoculated (h)GSH depleted roots. Quantitative reverse transcription polymerase chain reaction analysis confirmed the changes in mRNA levels. This transcriptomic analysis shows a down-regulation of genes involved in meristem formation and a modulation of the expression of stress-related genes in (h)GSH-depleted plants. Promoter-beta-glucuronidase histochemical analysis showed that the putative MtPIP2 aquaporin might be up-regulated during nodule meristem formation and that this up-regulation is inhibited under (h)GSH depletion. (h)GSH depletion enhances the expression of salicylic acid (SA)-regulated genes after S. meliloti infection and the expression of SA-regulated genes after exogenous SA treatment. Modification of water transport and SA signaling pathway observed under (h)GSH deficiency contribute to explain how (h)GSH depletion alters the proper development of the symbiotic interaction.

  10. Medicago truncatula increases its iron-uptake mechanisms in response to volatile organic compounds produced by Sinorhizobium meliloti.

    Science.gov (United States)

    Orozco-Mosqueda, Maria del Carmen; Macías-Rodríguez, Lourdes I; Santoyo, Gustavo; Farías-Rodríguez, Rodolfo; Valencia-Cantero, Eduardo

    2013-11-01

    Medicago truncatula represents a model plant species for understanding legume-bacteria interactions. M. truncatula roots form a specific root-nodule symbiosis with the nitrogen-fixing bacterium Sinorhizobium meliloti. Symbiotic nitrogen fixation generates high iron (Fe) demands for bacterial nitrogenase holoenzyme and plant leghemoglobin proteins. Leguminous plants acquire Fe via "Strategy I," which includes mechanisms such as rhizosphere acidification and enhanced ferric reductase activity. In the present work, we analyzed the effect of S. meliloti volatile organic compounds (VOCs) on the Fe-uptake mechanisms of M. truncatula seedlings under Fe-deficient and Fe-rich conditions. Axenic cultures showed that both plant and bacterium modified VOC synthesis in the presence of the respective symbiotic partner. Importantly, in both Fe-rich and -deficient experiments, bacterial VOCs increased the generation of plant biomass, rhizosphere acidification, ferric reductase activity, and chlorophyll content in plants. On the basis of our results, we propose that M. truncatula perceives its symbiont through VOC emissions, and in response, increases Fe-uptake mechanisms to facilitate symbiosis.

  11. Differential antifungal activity of alfalfa (Medicago santva L. saponins originated from roots and aerial parts for some ornamental plant pathogens

    Directory of Open Access Journals (Sweden)

    Alicja Saniewska

    2013-12-01

    Full Text Available The total saponins isolated from aerial parts and roots of alfalfa (Medicago sativa L. at the concentration of 0,01%, 0,05% and 0,1% showed differential influence on the mycelium growth of Alternaria zinniae, Botrytis cinerea, Botrytis tulipae, Phoma narcissi, Phoma poolensis and Rhizoctonia solani. A higher inhibitory effect on in vitro growth of mycelium of all tested pathogens indicated saponins from roots of alfalfa than from aerial parts. Tested saponins from roots at lhe concentration of 0,1% totally inhibited linear growth of Phoma narcissi, and linear growth of Alternaria zinniae was limited about 67%, Botrytis cinerea about 74%, Botrytis tulipae about 68%, Phoma poolensis about 38%, and Rhizoctonia solani about 74% in comparison to the control. The saponins of alfalfa from roots at the concentration of 0,1% and 0,2% applied as preinoculation sprays evidently inhibited the development of Phoma narcissi on Hippeastrum leaves. This dose of aerial saponins of alfalfa did not effect the development of necrotic spots on the leaves.

  12. Paenibacillus medicaginis sp. nov. a chitinolytic endophyte isolated from the root nodule of alfalfa (Medicago sativa L.).

    Science.gov (United States)

    Lai, Wei-An; Hameed, Asif; Lin, Shih-Yao; Hung, Mei-Hua; Hsu, Yi-Han; Liu, You-Cheng; Shahina, Mariyan; Shen, Fo-Ting; Young, Chiu-Chung

    2015-08-04

    A Gram-stain-variable, short-rod-shaped, endospore-forming, strictly aerobic, non-motile, chitinolytic and endophytic bacterium, designated strain CC-Alfalfa-19T, exhibiting unusual bipolar appendages was isolated from the root nodule of alfalfa (Medicago sativa L.) in Taiwan and subjected to a polyphasic taxonomy. Based on 16S rRNA gene sequence analysis, strain CC-Alfalfa-19T was found to be most closely related to Paenibacillus puldeungensis CAU 9324T (95.2 %), whereas other Paenibacillus species shared ≤95.0 % sequence similarity. The phylogenetic analysis revealed a distinct phyletic lineage established by strain CC-Alfalfa-19T with respect to other Paenibacillus species. Fatty acids comprised predominantly anteiso-C15:0, C16:0, anteiso-C17:0 and iso-C16. Menaquinone 7 (MK-7) was identified as the sole respiratory quinone and the genomic DNA G+C content was 42.7 mol%. Polar lipids included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylmonomethylethanolamine, phosphatidylethanolamine, an unidentified glycolipid and an unidentified lipid. The diagnostic diamino acid found in the cell-wall peptidoglycan was meso-diaminopimelic acid. Based on the polyphasic taxonomic evidences that were in line with the genus Paenibacillus and additional distinguishing characteristics, strain CC-Alfalfa-19T is considered to represent a novel species, for which the name Paenibacillus medicaginis sp. nov. (type strain CC-Alfalfa-19T = BCRC 80441T = JCM 18446T) is proposed.

  13. Characterization of the plant growth promoting bacterium, Enterobacter cloacae MSR1, isolated from roots of non-nodulating Medicago sativa.

    Science.gov (United States)

    Khalifa, Ashraf Y Z; Alsyeeh, Abdel-Moneium; Almalki, Mohammed A; Saleh, Farag A

    2016-01-01

    The aim of the present study was to characterize the endophytic bacterial strain designated MSR1 that was isolated from inside the non-nodulating roots of Medicago sativa after surface-sterilization. MSR1 was identified as Enterobacter cloacae using both 16S rDNA gene sequence analysis and API20E biochemical identification system (Biomerieux, France). Furthermore, this bacterium was characterized using API50CH kit (Biomerieux, France) and tested for antibacterial activities against some food borne pathogens. The results showed that E. cloacae consumed certain carbohydrates such as glycerol, d-xylose, d-maltose and esculin melibiose as a sole carbon source and certain amino acids such as arginine, tryptophan ornithine as nitrogen source. Furthermore, MSR1 possessed multiple plant-growth promoting characteristics; phosphate solubility, production of phytohormones acetoin and bioactive compounds. Inoculation of Pisum sativum with MSR1 significantly improved the growth parameters (the length and dry weight) of this economically important grain legume compared to the non-treated plants. To our knowledge, this is the first report addressing E. cloacae which exist in roots of alfalfa growing in Al-Ahsaa region. The results confirmed that E. cloacae exhibited traits for plant growth promoting and could be developed as an eco-friendly biofertilizer for P. sativum and probably for other important plant species in future.

  14. Medicago truncatula and Glycine max: Different Drought Tolerance and Similar Local Response of the Root Nodule Proteome.

    Science.gov (United States)

    Gil-Quintana, Erena; Lyon, David; Staudinger, Christiana; Wienkoop, Stefanie; González, Esther M

    2015-12-04

    Legume crops present important agronomical and environmental advantages mainly due to their capacity to reduce atmospheric N2 to ammonium via symbiotic nitrogen fixation (SNF). This process is very sensitive to abiotic stresses such as drought, but the mechanism underlying this response is not fully understood. The goal of the current work is to compare the drought response of two legumes with high economic impact and research importance, Medicago truncatula and Glycine max, by characterizing their root nodule proteomes. Our results show that, although M. truncatula exhibits lower water potential values under drought conditions compared to G. max, SNF declined analogously in the two legumes. Both of their nodule proteomes are very similar, and comparable down-regulation responses in the diverse protein functional groups were identified (mainly proteins related to the metabolism of carbon, nitrogen, and sulfur). We suggest lipoxygenases and protein turnover as newly recognized players in SNF regulation. Partial drought conditions applied to a split-root system resulted in the local down-regulation of the entire proteome of drought-stressed nodules in both legumes. The high degree of similarity between both legume proteomes suggests that the vast amount of research conducted on M. truncatula could be applied to economically important legume crops, such as soybean.

  15. Two distinct plastid genome configurations and unprecedented intraspecies length variation in the accD coding region in Medicago truncatula.

    Science.gov (United States)

    Gurdon, Csanad; Maliga, Pal

    2014-08-01

    We fully sequenced four and partially sequenced six additional plastid genomes of the model legume Medicago truncatula. Three accessions, Jemalong 2HA, Borung and Paraggio, belong to ssp. truncatula, and R108 to ssp. tricycla. We report here that the R108 ptDNA has a ~45-kb inversion compared with the ptDNA in ssp. truncatula, mediated by a short, imperfect repeat. DNA gel blot analyses of seven additional ssp. tricycla accessions detected only one of the two alternative genome arrangements, represented by three and four accessions each. Furthermore, we found a variable number of repeats in the essential accD and ycf1 coding regions. The repeats within accD are recombinationally active, yielding variable-length insertions and deletions in the central part of the coding region. The length of ACCD was distinct in each of the 10 sequenced ecotypes, ranging between 650 and 796 amino acids. The repeats in the ycf1 coding region are also recombinationally active, yielding short indels in 10 regions of the reading frames. Thus, the plastid genome variability we report here could be linked to repeat-mediated genome rearrangements. However, the rate of recombination was sufficiently low, so that no heterogeneity of ptDNA could be observed in populations maintained by single-seed descent.

  16. Differential mRNA Translation in Medicago truncatula Accessions with Contrasting Responses to Ozone-Induced Oxidative Stress

    Institute of Scientific and Technical Information of China (English)

    Michael Puckette; Niranjani J. lyer; YuhongTang; Xin-Bin Dai; Patrick Zhao; Ramamurthy Mahalingam

    2012-01-01

    Acute ozone is a model abiotic elicitor of oxidative stress and a useful tool for understanding biochemical and molecular events during oxidative signaling.Two Medicago truncatula accessions with contrasting responses to ozone were used to examine translational regulation during ozone stress.In ozone-resistant JE154,significant reduction in ribosome loading was observed within one hour of ozone treatment,suggesting energy homeostasis as a vital factor for oxidative stress management.Polysomal RNA-based expression profiling with Affymetrix arrays revealed extensive changes in the translatomes of both accessions.Messenger RNAs with low GC content in their 5' and 3'-UTRs were preferentially associated with polysomes during oxidative stress.Genebins analysis revealed extensive changes in various gene ontologies in both accessions.Extensive changes in nicotinate and nicotinamide metabolism genes were corroborated with increased levels of NAD+ and NADH in JE154.The significantly lower NAD+:NADH redox status in JE154,in conjunction with higher ATP amounts,provided a cellular milieu conducive for overcoming oxidative stress.Low levels of ATP,NADH,and suppression of antioxidant defense responses,abet build-up of ozone-derived ROS and ultimately lead to oxidative cell death in Jemalong.

  17. The arbuscular mycorrhizal fungus Glomus mosseae gives contradictory effects on phosphorus and arsenic acquisition by Medicago sativa Linn

    Energy Technology Data Exchange (ETDEWEB)

    Chen Baodong [Department of Soil Environmental Sciences/State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Xiao Xueyi [Department of Soil Environmental Sciences/State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Zhu Yongguan [Department of Soil Environmental Sciences/State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China)]. E-mail: ygzhu@rcees.ac.en; Smith, F. Andrew [Soil and Land Systems, School of Earth and Environmental Sciences, Waite Campus, University of Adelaide, South Australia 5005 (Australia); Miao Xie, Z. [Department of Environmental Science and Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Smith, Sally E. [Soil and Land Systems, School of Earth and Environmental Sciences, Waite Campus, University of Adelaide, South Australia 5005 (Australia)

    2007-07-01

    Mycorrhizal fungi may play an important role in protecting plants against arsenic (As) contamination. However, little is known about the direct and indirect involvement of arbuscular mycorrhizal fungi (AMF) in detoxification mechanisms. A compartmented pot cultivation system ('cross-pots') is used here to investigate the roles of AMF Glomus mosseae in plant phosphorus (P) and As acquisition by Medicago sativa, and P-As interactions. The results indicate that fungal colonization dramatically increased plant dry weight by a factor of around 6, and also substantially increased both plant P and As contents (i.e. total uptake). Irrespective of P and As addition levels, AM plants had shoot and root P concentrations 2 fold higher, but As concentrations significantly lower, than corresponding uninoculated controls. The decreased shoot As concentrations were largely due to 'dilution effects' that resulted from stimulated growth of AM plants and reduced As partitioning to shoots. The study provides further evidence for the protective effects of AMF on host plants against As contamination, and have uncovered key aspects of underlying mechanisms. The possible application of AMF in remediation practices is discussed.

  18. Regulatory patterns of a large family of defensin-like genes expressed in nodules of Medicago truncatula.

    Directory of Open Access Journals (Sweden)

    Sumitha Nallu

    Full Text Available Root nodules are the symbiotic organ of legumes that house nitrogen-fixing bacteria. Many genes are specifically induced in nodules during the interactions between the host plant and symbiotic rhizobia. Information regarding the regulation of expression for most of these genes is lacking. One of the largest gene families expressed in the nodules of the model legume Medicago truncatula is the nodule cysteine-rich (NCR group of defensin-like (DEFL genes. We used a custom Affymetrix microarray to catalog the expression changes of 566 NCRs at different stages of nodule development. Additionally, bacterial mutants were used to understand the importance of the rhizobial partners in induction of NCRs. Expression of early NCRs was detected during the initial infection of rhizobia in nodules and expression continued as nodules became mature. Late NCRs were induced concomitantly with bacteroid development in the nodules. The induction of early and late NCRs was correlated with the number and morphology of rhizobia in the nodule. Conserved 41 to 50 bp motifs identified in the upstream 1,000 bp promoter regions of NCRs were required for promoter activity. These cis-element motifs were found to be unique to the NCR family among all annotated genes in the M. truncatula genome, although they contain sub-regions with clear similarity to known regulatory motifs involved in nodule-specific expression and temporal gene regulation.

  19. Medicago truncatula natural resistance-associated macrophage Protein1 is required for iron uptake by rhizobia-infected nodule cells.

    Science.gov (United States)

    Tejada-Jiménez, Manuel; Castro-Rodríguez, Rosario; Kryvoruchko, Igor; Lucas, M Mercedes; Udvardi, Michael; Imperial, Juan; González-Guerrero, Manuel

    2015-05-01

    Iron is critical for symbiotic nitrogen fixation (SNF) as a key component of multiple ferroproteins involved in this biological process. In the model legume Medicago truncatula, iron is delivered by the vasculature to the infection/maturation zone (zone II) of the nodule, where it is released to the apoplast. From there, plasma membrane iron transporters move it into rhizobia-containing cells, where iron is used as the cofactor of multiple plant and rhizobial proteins (e.g. plant leghemoglobin and bacterial nitrogenase). MtNramp1 (Medtr3g088460) is the M. truncatula Natural Resistance-Associated Macrophage Protein family member, with the highest expression levels in roots and nodules. Immunolocalization studies indicate that MtNramp1 is mainly targeted to the plasma membrane. A loss-of-function nramp1 mutant exhibited reduced growth compared with the wild type under symbiotic conditions, but not when fertilized with mineral nitrogen. Nitrogenase activity was low in the mutant, whereas exogenous iron and expression of wild-type MtNramp1 in mutant nodules increased nitrogen fixation to normal levels. These data are consistent with a model in which MtNramp1 is the main transporter responsible for apoplastic iron uptake by rhizobia-infected cells in zone II.

  20. Transcriptomic and metabolomic analyses identify a role for chlorophyll catabolism and phytoalexin during Medicago nonhost resistance against Asian soybean rust.

    Science.gov (United States)

    Ishiga, Yasuhiro; Uppalapati, Srinivasa Rao; Gill, Upinder S; Huhman, David; Tang, Yuhong; Mysore, Kirankumar S

    2015-08-12

    Asian soybean rust (ASR) caused by Phakopsora pachyrhizi is a devastating foliar disease affecting soybean production worldwide. Understanding nonhost resistance against ASR may provide an avenue to engineer soybean to confer durable resistance against ASR. We characterized a Medicago truncatula-ASR pathosystem to study molecular mechanisms of nonhost resistance. Although urediniospores formed appressoria and penetrated into epidermal cells of M. truncatula, P. pachyrhizi failed to sporulate. Transcriptomic analysis revealed the induction of phenylpropanoid, flavonoid and isoflavonoid metabolic pathway genes involved in the production of phytoalexin medicarpin in M. truncatula upon infection with P. pachyrhizi. Furthermore, genes involved in chlorophyll catabolism were induced during nonhost resistance. We further characterized one of the chlorophyll catabolism genes, Stay-green (SGR), and demonstrated that the M. truncatula sgr mutant and alfalfa SGR-RNAi lines showed hypersensitive-response-like enhanced cell death upon inoculation with P. pachyrhizi. Consistent with transcriptomic analysis, metabolomic analysis also revealed the accumulation of medicarpin and its intermediate metabolites. In vitro assay showed that medicarpin inhibited urediniospore germination and differentiation. In addition, several triterpenoid saponin glycosides accumulated in M. truncatula upon inoculation with P. pachyrhizi. In summary, using multi-omic approaches, we identified a correlation between phytoalexin production and M. truncatula defense responses against ASR.

  1. The Medicago truncatula lysin [corrected] motif-receptor-like kinase gene family includes NFP and new nodule-expressed genes.

    Science.gov (United States)

    Arrighi, Jean-François; Barre, Annick; Ben Amor, Besma; Bersoult, Anne; Soriano, Lidia Campos; Mirabella, Rossana; de Carvalho-Niebel, Fernanda; Journet, Etienne-Pascal; Ghérardi, Michèle; Huguet, Thierry; Geurts, René; Dénarié, Jean; Rougé, Pierre; Gough, Clare

    2006-09-01

    Rhizobial Nod factors are key symbiotic signals responsible for starting the nodulation process in host legume plants. Of the six Medicago truncatula genes controlling a Nod factor signaling pathway, Nod Factor Perception (NFP) was reported as a candidate Nod factor receptor gene. Here, we provide further evidence for this by showing that NFP is a lysin [corrected] motif (LysM)-receptor-like kinase (RLK). NFP was shown both to be expressed in association with infection thread development and to be involved in the infection process. Consistent with deviations from conserved kinase domain sequences, NFP did not show autophosphorylation activity, suggesting that NFP needs to associate with an active kinase or has unusual functional characteristics different from classical kinases. Identification of nine new M. truncatula LysM-RLK genes revealed a larger family than in the nonlegumes Arabidopsis (Arabidopsis thaliana) or rice (Oryza sativa) of at least 17 members that can be divided into three subfamilies. Three LysM domains could be structurally predicted for all M. truncatula LysM-RLK proteins, whereas one subfamily, which includes NFP, was characterized by deviations from conserved kinase sequences. Most of the newly identified genes were found to be expressed in roots and nodules, suggesting this class of receptors may be more extensively involved in nodulation than was previously known.

  2. Microgravity Effects on the Early Events of Biological Nitrogen Fixation in Medicago Truncatula: Results from the SyNRGE Experiment

    Science.gov (United States)

    Stutte, Gary W.; Roberts, Michael S.

    2013-02-01

    SyNRGE (Symbiotic Nodulation in a Reduced Gravity Environment) was a sortie mission on STS-135 in the Biological Research in Canisters (BRIC) hardware to study the effect of μg on a plant-microbe symbiosis resulting in biological nitrogen fixation. Medicago truncatula, a model species for the legume family, was inoculated with its bacterial symbiont, Sinorhizobium meliloti, to observe early biomolecular events associated with infection and nodulation in Petri Dish Fixation Units (PDFU’s). Two sets of experiments were conducted in orbit and in 24-hour delayed ground controls. Experiments were designed to determine if S. meliloti would infect M. truncatula and initiate biomolecular changes associated with nodule formation and if the μg environment altered the host plant and/or bacteria to induce nodule formation upon return to 1g. Initial analysis results demonstrate that the legumes and bacteria cultivated in μg have potential to develop a symbiotic interaction, but suggest that μg alters their ability to form nodules upon return to 1g. (Research supported by NASA ESMD/ Advance Capabilities Division grant NNX10AR09A)

  3. Jasmonate Signalling and Defence Responses in the Model Legume Medicago truncatula—A Focus on Responses to Fusarium Wilt Disease

    Directory of Open Access Journals (Sweden)

    Louise F. Thatcher

    2016-02-01

    Full Text Available Jasmonate (JA-mediated defences play important roles in host responses to pathogen attack, in particular to necrotrophic fungal pathogens that kill host cells in order to extract nutrients and live off the dead plant tissue. The root-infecting fungal pathogen Fusarium oxysporum initiates a necrotrophic growth phase towards the later stages of its lifecycle and is responsible for devastating Fusarium wilt disease on numerous legume crops worldwide. Here we describe the use of the model legume Medicago truncatula to study legume–F. oxysporum interactions and compare and contrast this against knowledge from other model pathosystems, in particular Arabidopsis thaliana–F. oxysporum interactions. We describe publically-available genomic, transcriptomic and genetic (mutant resources developed in M. truncatula that enable dissection of host jasmonate responses and apply aspects of these herein during the M. truncatula-–F. oxysporum interaction. Our initial results suggest not all components of JA-responses observed in M. truncatula are shared with Arabidopsis in response to F. oxysporum infection.

  4. Allelic differences in Medicago truncatula NIP/LATD mutants correlate with their encoded proteins' transport activities in planta.

    Science.gov (United States)

    Salehin, Mohammad; Huang, Ying-Sheng; Bagchi, Rammyani; Sherrier, D Janine; Dickstein, Rebecca

    2013-02-01

    Medicago truncatula NIP/LATD gene, required for symbiotic nitrogen fixing nodule and root architecture development, encodes a member of the NRT1(PTR) family that demonstrates high-affinity nitrate transport in Xenopus laevis oocytes. Of three Mtnip/latd mutant proteins, one retains high-affinity nitrate transport in oocytes, while the other two are nitrate-transport defective. To further examine the mutant proteins' transport properties, the missense Mtnip/latd alleles were expressed in Arabidopsis thaliana chl1-5, resistant to the herbicide chlorate because of a deletion spanning the nitrate transporter AtNRT1.1(CHL1) gene. Mtnip-3 expression restored chlorate sensitivity in the Atchl1-5 mutant, similar to wild type MtNIP/LATD, while Mtnip-1 expression did not. The high-affinity nitrate transporter AtNRT2.1 gene was expressed in Mtnip-1 mutant roots; it did not complement, which could be caused by several factors. Together, these findings support the hypothesis that MtNIP/LATD may have another biochemical activity.

  5. Unraveling the effect of arsenic on the model Medicago-Ensifer interaction: a transcriptomic meta-analysis.

    Science.gov (United States)

    Lafuente, Alejandro; Pérez-Palacios, Patricia; Doukkali, Bouchra; Molina-Sánchez, María D; Jiménez-Zurdo, José I; Caviedes, Miguel A; Rodríguez-Llorente, Ignacio D; Pajuelo, Eloísa

    2015-01-01

    The genetic regulation underlying the effect of arsenic (As(III)) on the model symbiosis Medicago-Ensifer was investigated using a combination of physiological (split-roots), microscopy and genetic (microarrays, qRT-PCR and composite plants) tools. Nodulation was very sensitive to As(III) (median inhibitory dose (ID50) = 20 μM). The effect on root elongation and on nodulation was local (nonsystemic). A battery of stress (salt, drought, heat shock, metals, etc.)-related genes were induced. Glutathione played a pivotal role in tolerance/detoxification, together with secondary metabolites ((iso)flavonoids and phenylpropanoids). However, antioxidant enzymes were not activated. Concerning the symbiotic interaction, molecular evidence suggesting that rhizobia alleviate As stress is for the first time provided. Chalcone synthase (which is involved in the first step of the legume-rhizobia cross-talk) was strongly enhanced, suggesting that the plants are biased to establish symbiotic interactions under As(III) stress. In contrast, 13 subsequent nodulation genes (involved in nodulation factors (Nod factors) perception, infection, thread initiation and progression, and nodule morphogenesis) were repressed. Overexpression of the ethylene responsive factor ERN in composite plants reduced root stress and partially restored nodulation, whereas overexpression of the early nodulin ENOD12 enhanced nodulation both in the presence and, particularly, in the absence of As, without affecting root elongation. Several transcription factors were identified, which could be additional targets for genetic engineering aiming to improve nodulation and/or alleviate root stress induced by this toxic.

  6. Genome sequence of Ensifer medicae Di28; an effective N2-fixing microsymbiont of Medicago murex and M. polymorpha.

    Science.gov (United States)

    Garau, Giovanni; Terpolilli, Jason; Hill, Yvette; Tian, Rui; Howieson, John; Bräu, Lambert; Goodwin, Lynne; Han, James; Reddy, Tbk; Huntemann, Marcel; Pati, Amrita; Woyke, Tanja; Mavromatis, Konstantinos; Markowitz, Victor; Ivanova, Natalia; Kyrpides, Nikos; Reeve, Wayne

    2014-01-01

    Ensifer medicae Di28 is an aerobic, motile, Gram-negative, non-spore-forming rod that can exist as a soil saprophyte or as a legume microsymbiont of Medicago spp. Di28 was isolated in 1998 from a nodule recovered from the roots of M. polymorpha growing in the south east of Sardinia (Italy). Di28 is an effective microsymbiont of the annual forage legumes M. polymorpha and M. murex and is capable of establishing a partially effective symbiotic association with the perennial M. sativa. Here we describe the features of E. medicae Di28, together with genome sequence information and its annotation. The 6,553,624 bp standard draft genome is arranged into 104 scaffolds of 104 contigs containing 6,394 protein-coding genes and 75 RNA-only encoding genes. This rhizobial genome is one of 100 sequenced as part of the DOE Joint Genome Institute 2010 Genomic Encyclopedia for Bacteria and Archaea-Root Nodule Bacteria (GEBA-RNB) project.

  7. Arbuscular mycorrhizal symbiosis influences arsenic accumulation and speciation in Medicago truncatula L. in arsenic-contaminated soil.

    Science.gov (United States)

    Zhang, Xin; Ren, Bai-Hui; Wu, Song-Lin; Sun, Yu-Qing; Lin, Ge; Chen, Bao-Dong

    2015-01-01

    In two pot experiments, wild type and a non-mycorrhizal mutant (TR25:3-1) of Medicago truncatula were grown in arsenic (As)-contaminated soil to investigate the influences of arbuscular mycorrhizal fungi (AMF) on As accumulation and speciation in host plants. The results indicated that the plant biomass of M. truncatula was dramatically increased by AM symbiosis. Mycorrhizal colonization significantly increased phosphorus concentrations and decreased As concentrations in plants. Moreover, mycorrhizal colonization generally increased the percentage of arsenite in total As both in shoots and roots, while dimethylarsenic acid (DMA) was only detected in shoots of mycorrhizal plants. The results suggested that AMF are most likely to get involved in the methylating of inorganic As into less toxic organic DMA and also in the reduction of arsenate to arsenite. The study allowed a deeper insight into the As detoxification mechanisms in AM associations. By using the mutant M. truncatula, we demonstrated the importance of AMF in plant As tolerance under natural conditions.

  8. Increase in 4-coumaryl alcohol units during lignification in alfalfa (Medicago sativa) alters the extractability and molecular weight of lignin.

    Science.gov (United States)

    Ziebell, Angela; Gracom, Kristen; Katahira, Rui; Chen, Fang; Pu, Yunqiao; Ragauskas, Art; Dixon, Richard A; Davis, Mark

    2010-12-10

    The lignin content of biomass can impact the ease and cost of biomass processing. Lignin reduction through breeding and genetic modification therefore has potential to reduce costs in biomass-processing industries (e.g. pulp and paper, forage, and lignocellulosic ethanol). We investigated compositional changes in two low-lignin alfalfa (Medicago sativa) lines with antisense down-regulation of p-coumarate 3-hydroxylase (C3H) or hydroxycinnamoyl-CoA:shikimate hydroxycinnamoyltransferase (HCT). We investigated whether the difference in reactivity during lignification of 4-coumaryl alcohol (H) monomers versus the naturally dominant sinapyl alcohol and coniferyl alcohol lignin monomers alters the lignin structure. Sequential base extraction readily reduced the H monomer content of the transgenic lines, leaving a residual lignin greatly enriched in H subunits; the extraction profile highlighted the difference between the control and transgenic lines. Gel permeation chromatography of isolated ball-milled lignin indicated significant changes in the weight average molecular weight distribution of the control versus transgenic lines (CTR1a, 6000; C3H4a, 5500; C3H9a, 4000; and HCT30a, 4000).

  9. Increase in 4-Coumaryl Alcohol Units during Lignification in Alfalfa (Medicago sativa) Alters the Extractability and Molecular Weight of Lignin*

    Science.gov (United States)

    Ziebell, Angela; Gracom, Kristen; Katahira, Rui; Chen, Fang; Pu, Yunqiao; Ragauskas, Art; Dixon, Richard A.; Davis, Mark

    2010-01-01

    The lignin content of biomass can impact the ease and cost of biomass processing. Lignin reduction through breeding and genetic modification therefore has potential to reduce costs in biomass-processing industries (e.g. pulp and paper, forage, and lignocellulosic ethanol). We investigated compositional changes in two low-lignin alfalfa (Medicago sativa) lines with antisense down-regulation of p-coumarate 3-hydroxylase (C3H) or hydroxycinnamoyl-CoA:shikimate hydroxycinnamoyltransferase (HCT). We investigated whether the difference in reactivity during lignification of 4-coumaryl alcohol (H) monomers versus the naturally dominant sinapyl alcohol and coniferyl alcohol lignin monomers alters the lignin structure. Sequential base extraction readily reduced the H monomer content of the transgenic lines, leaving a residual lignin greatly enriched in H subunits; the extraction profile highlighted the difference between the control and transgenic lines. Gel permeation chromatography of isolated ball-milled lignin indicated significant changes in the weight average molecular weight distribution of the control versus transgenic lines (CTR1a, 6000; C3H4a, 5500; C3H9a, 4000; and HCT30a, 4000). PMID:20921228

  10. The Effect of Priming on Germination and Seedling Growth of Alfalfa (Medicago sativa L. under Salinity Stress

    Directory of Open Access Journals (Sweden)

    Jorjandi M.

    2012-08-01

    Full Text Available Salinity stress is an abiotic stress which has harmful effects on germination, growth and yield of alfalfa (Medicago sativa L. in many parts of the world. Seed priming is a way of increasing salt tolerance of plants. In this study, the effect of seed priming on germination and growth of alfalfa seedlings, Bami cultivar, under salinity condition was investigated. According to germination percentage of seeds under In vitro conditions, salicylic acid, Vitamin B12 and distilled water were selected as primes under salinities of 0, 5 and 10 ds.m-2 NaCl solution for further studies. These studies were carried out in a factorial experiment based on Completely Randomized Design (CRD with three replications in greenhouse under controlled condition (25°C in day/night. Parameters like percentage and rate of germination, dry and fresh weight of seedling and leaf number were measured. Based on our research All of the treatments (priming, salinity and the interaction of priming with salinity significantly (p<0.01 affected Hypocotyl length and radicle length and in low level of salt (0 ds.m2 germination and seedling growth indexes enhanced and also with applying salicylic acid both hypocotyl and radicle lengths improved.

  11. Deep-sequencing transcriptome analysis of field-grown Medicago sativa L. crown buds acclimated to freezing stress.

    Science.gov (United States)

    Song, Lili; Jiang, Lin; Chen, Yue; Shu, Yongjun; Bai, Yan; Guo, Changhong

    2016-09-01

    Medicago sativa L. (alfalfa) 'Zhaodong' is an important forage legume that can safely survive in northern China where winter temperatures reach as low as -30 °C. Survival of alfalfa following freezing stress depends on the amount and revival ability of crown buds. In order to investigate the molecular mechanisms of frost tolerance in alfalfa, we used transcriptome sequencing technology and bioinformatics strategies to analyze crown buds of field-grown alfalfa during winter. We statistically identified a total of 5605 differentially expressed genes (DEGs) involved in freezing stress including 1900 upregulated and 3705 downregulated DEGs. We validated 36 candidate DEGs using qPCR to confirm the accuracy of the RNA-seq data. Unlike other recent studies, this study employed alfalfa plants grown in the natural environment. Our results indicate that not only the CBF orthologs but also membrane proteins, hormone signal transduction pathways, and ubiquitin-mediated proteolysis pathways indicate the presence of a special freezing adaptation mechanism in alfalfa. The antioxidant defense system may rapidly confer freezing tolerance to alfalfa. Importantly, biosynthesis of secondary metabolites and phenylalanine metabolism, which is of potential importance in coordinating freezing tolerance with growth and development, were downregulated in subzero temperatures. The adaptive mechanism for frost tolerance is a complex multigenic process that is not well understood. This systematic analysis provided an in-depth view of stress tolerance mechanisms in alfalfa.

  12. Identification of molecular markers associated with Verticillium wilt resistance in alfalfa (Medicago sativa L. using high-resolution melting.

    Directory of Open Access Journals (Sweden)

    Tiejun Zhang

    Full Text Available Verticillium wilt, caused by the soilborne fungus, Verticillium alfalfae, is one of the most serious diseases of alfalfa (Medicago sativa L. worldwide. To identify loci associated with resistance to Verticillium wilt, a bulk segregant analysis was conducted in susceptible or resistant pools constructed from 13 synthetic alfalfa populations, followed by association mapping in two F1 populations consisted of 352 individuals. Simple sequence repeat (SSR and single nucleotide polymorphism (SNP markers were used for genotyping. Phenotyping was done by manual inoculation of the pathogen to replicated cloned plants of each individual and disease severity was scored using a standard scale. Marker-trait association was analyzed by TASSEL. Seventeen SNP markers significantly associated with Verticillium wilt resistance were identified and they were located on chromosomes 1, 2, 4, 7 and 8. SNP markers identified on chromosomes 2, 4 and 7 co-locate with regions of Verticillium wilt resistance loci reported in M. truncatula. Additional markers identified on chromosomes 1 and 8 located the regions where no Verticillium resistance locus has been reported. This study highlights the value of SNP genotyping by high resolution melting to identify the disease resistance loci in tetraploid alfalfa. With further validation, the markers identified in this study could be used for improving resistance to Verticillium wilt in alfalfa breeding programs.

  13. P-HYDROXYPHENYLPYRUVATE DIOXYGENASE from Medicago sativa is involved in vitamin E biosynthesis and abscisic acid-mediated seed germination

    Science.gov (United States)

    Jiang, Jishan; Chen, Zhihong; Ban, Liping; Wu, Yudi; Huang, Jianping; Chu, Jinfang; Fang, Shuang; Wang, Zan; Gao, Hongwen; Wang, Xuemin

    2017-01-01

    P-HYDROXYPHENYLPYRUVATE DIOXYGENASE (HPPD) is the first committed enzyme involved in the biosynthesis of vitamin E, and is characterized by catalyzing the conversion of p-hydroxyphenyl pyruvate (HPP) to homogentisic acid (HGA). Here, an HPPD gene was cloned from Medicago sativa L. and designated MsHPPD, which was expressed at high levels in alfalfa leaves. PEG 6000 (polyethylene glycol), NaCl, abscisic acid and salicylic acid were shown to significantly induce MsHPPD expression, especially in the cotyledons and root tissues. Overexpression of MsHPPD was found to significantly increase the level of β-tocotrienol and the total vitamin E content in Arabidopsis seeds. Furthermore, these transgenic Arabidopsis seeds exhibited an accelerated germination time, compared with wild-type seeds under normal conditions, as well as under NaCl and ABA treatments. Meanwhile, the expression level of several genes associated with ABA biosynthesis (NCED3, NCED5 and NCED9) and the ABA signaling pathway (RAB18, ABI3 and ABI5) were significantly down-regulated in MsHPPD-overexpressing transgenic lines, as well as the total free ABA content. Taken together, these results demonstrate that MsHPPD functions not only in the vitamin E biosynthetic pathway, but also plays a critical role in seed germination via affecting ABA biosynthesis and signaling. PMID:28084442

  14. Identification of transcriptome involved in atrazine detoxification and degradation in alfalfa (Medicago sativa) exposed to realistic environmental contamination.

    Science.gov (United States)

    Zhang, Jing Jing; Lu, Yi Chen; Zhang, Shu Hao; Lu, Feng Fan; Yang, Hong

    2016-08-01

    Plants are constantly exposed to a variety of toxic compounds (or xenobiotics) such as pesticides (or herbicides). Atrazine (ATZ) as herbicide has become one of the environmental contaminants due to its intensive use during crop production. Plants have evolved strategies to cope with the adverse impact of ATZ. However, the mechanism for ATZ degradation and detoxification in plants is largely unknown. Here we employed a global RNA-sequencing (RNA-Seq) strategy to dissect transcriptome variation in alfalfa (Medicago sativa) exposed to ATZ. Four libraries were constructed including Root-ATZ (root control, ATZ-free), Shoot-ATZ, Root+ATZ (root treated with ATZ) and Shoot+ATZ. Hierarchical clustering was performed to display the expression patterns for all differentially expressed genes (DEGs) under ATZ exposure. Transcripts involved in ATZ detoxification, stress responses (e.g. oxidation and reduction, conjugation and hydrolytic reactions), and regulations of cysteine biosynthesis were identified. Several genes encoding glycosyltransferases, glutathione S-transferases or ABC transporters were up-regulated notably. Also, many other genes involved in oxidation-reduction, conjugation, and hydrolysis for herbicide degradation were differentially expressed. These results suggest that ATZ in alfalfa can be detoxified or degraded through different pathways. The expression patterns of some DEGs by high-throughput sequencing were well confirmed by qRT-PCR. Our results not only highlight the transcriptional complexity in alfalfa exposed to ATZ but represent a major improvement for analyzing transcriptional changes on a large scale as well.

  15. New pharmacological properties of Medicago sativa and Saponaria officinalis saponin-rich fractions addressed to Candida albicans.

    Science.gov (United States)

    Sadowska, Beata; Budzyńska, Aleksandra; Więckowska-Szakiel, Marzena; Paszkiewicz, Małgorzata; Stochmal, Anna; Moniuszko-Szajwaj, Barbara; Kowalczyk, Mariusz; Różalska, Barbara

    2014-08-01

    The antifungal activity of the saponin-rich fractions (SFs) from Medicago sativa (aerial parts and roots) and Saponaria officinalis (used as a well-known source of plant saponins) against Candida albicans reference and clinical strains, their yeast-to-hyphal conversion, adhesion, and biofilm formation was investigated. Direct fungicidal/fungistatic properties of the tested phytochemicals used alone, as well as their synergy with azoles (probably resulting from yeast cell wall instability) were demonstrated. Here, to the best of our knowledge, we report for the first time the ability of saponin-rich extracts of M. sativa and S. officinalis to inhibit C. albicans germ tube formation, limit hyphal growth, reduce yeast adherence and biofilm formation, and eradicate mature (24 h) Candida biofilm. Moreover, M. sativa SFs (mainly obtained from aerial parts), in the range of concentrations which were active modulators of Candida virulence factors, exhibited low cytotoxicity against the mouse fibroblast line L929. These properties seem to be very promising in the context of using plant-derived SFs as potential novel antifungal therapeutics supporting classic drugs or as ingredients of disinfectants.

  16. The Sinorhizobium meliloti EmrR regulator is required for efficient colonization of Medicago sativa root nodules.

    Science.gov (United States)

    Santos, Mário R; Marques, Andreia T; Becker, Jörg D; Moreira, Leonilde M

    2014-04-01

    The nitrogen-fixing bacterium Sinorhizobium meliloti must adapt to diverse conditions encountered during its symbiosis with leguminous plants. We characterized a new symbiotically relevant gene, emrR (SMc03169), whose product belongs to the TetR family of repressors and is divergently transcribed from emrAB genes encoding a putative major facilitator superfamily-type efflux pump. An emrR deletion mutant produced more succinoglycan, displayed increased cell-wall permeability, and exhibited higher tolerance to heat shock. It also showed lower tolerance to acidic conditions, a reduced production of siderophores, and lower motility and biofilm formation. The simultaneous deletion of emrA and emrR genes restored the mentioned traits to the wild-type phenotype, except for survival under heat shock, which was lower than that displayed by the wild-type strain. Furthermore, the ΔemrR mutant as well as the double ΔemrAR mutant was impaired in symbiosis with Medicago sativa; it formed fewer nodules and competed poorly with the wild-type strain for nodule colonization. Expression profiling of the ΔemrR mutant showed decreased expression of genes involved in Nod-factor and rhizobactin biosynthesis and in stress responses. Expression of genes directing the biosynthesis of succinoglycan and other polysaccharides were increased. EmrR may therefore be involved in a regulatory network targeting membrane and cell wall modifications in preparation for colonization of root hairs during symbiosis.

  17. Relationship between photosynthetic capacity, nitrogen assimilation and nodule metabolism in alfalfa (Medicago sativa) grown with sewage sludge.

    Science.gov (United States)

    Antolín, M Carmen; Fiasconaro, M Laura; Sánchez-Díaz, Manuel

    2010-10-15

    Sewage sludge has been used as N fertilizer because it contains some of inorganic N, principally as nitrate and ammonium ions. However, sewage sludge addition to legumes could result in impaired nodule metabolism due to the presence of inorganic N from sludge. A greenhouse experiment was conducted to examine the effects of sewage sludge on growth, photosynthesis, nitrogen assimilation and nodule metabolism in alfalfa (Medicago sativa L. cv. Aragón). Plants were grown in pots with a mixture of perlite and vermiculite (2:1, v/v). The experiment included three treatments: (1) plants inoculated with rhizobia and amended with sewage sludge at rate of 10% (w/w) (RS); (2) plants inoculated with rhizobia without any amendment (R); and (3) non-inoculated plants fed with ammonium nitrate (N). N(2)-fixing plants had lower growth and sucrose phosphate synthase activity but higher photosynthesis than nitrate-fed plants because they compensated the carbon cost of the rhizobia. However, sewage sludge-treated plants evidenced a loss of carbon sink strength due to N(2) fixation by means of decreased photosynthetic capacity, leaf chlorophylls and N concentration in comparison to untreated plants. Sewage sludge did no affect nodulation but decreased nodule enzyme activities involved in carbon and N metabolisms that may lead to accumulation of toxic N-compounds.

  18. Multiple Autoregulation of Nodulation (AON Signals Identified through Split Root Analysis of Medicago truncatula sunn and rdn1 Mutants

    Directory of Open Access Journals (Sweden)

    Tessema Kassaw

    2015-04-01

    Full Text Available Nodulation is energetically costly to the host: legumes balance the nitrogen demand with the energy expense by limiting the number of nodules through long-distance signaling. A split root system was used to investigate systemic autoregulation of nodulation (AON in Medicago truncatula and the role of the AON genes RDN1 and SUNN in the regulatory circuit. Developing nodule primordia did not trigger AON in plants carrying mutations in RDN1 and SUNN genes, while wild type plants had fully induced AON within three days. However, despite lacking an early suppression response, AON mutants suppressed nodulation when roots were inoculated 10 days or more apart, correlated with the maturation of nitrogen fixing nodules. In addition to correlation between nitrogen fixation and suppression of nodulation, suppression by extreme nutrient stress was also observed in all genotypes and may be a component of the observed response due to the conditions of the assay. These results suggest there is more than one systemic regulatory circuit controlling nodulation in M. truncatula. While both signals are present in wild type plants, the second signal can only be observed in plants lacking the early repression (AON mutants. RDN1 and SUNN are not essential for response to the later signal.

  19. The NIN Transcription Factor Coordinates Diverse Nodulation Programs in Different Tissues of the Medicago truncatula Root[OPEN

    Science.gov (United States)

    Kim, Jiyoung; Frances, Lisa; Ding, Yiliang; Sun, Jongho; Guan, Dian; de Carvalho-Niebel, Fernanda; Oldroyd, Giles E.D.

    2015-01-01

    Biological nitrogen fixation in legumes occurs in nodules that are initiated in the root cortex following Nod factor recognition at the root surface, and this requires coordination of diverse developmental programs in these different tissues. We show that while early Nod factor signaling associated with calcium oscillations is limited to the root surface, the resultant activation of Nodule Inception (NIN) in the root epidermis is sufficient to promote cytokinin signaling and nodule organogenesis in the inner root cortex. NIN or a product of its action must be associated with the transmission of a signal between the root surface and the cortical cells where nodule organogenesis is initiated. NIN appears to have distinct functions in the root epidermis and the root cortex. In the epidermis, NIN restricts the extent of Early Nodulin 11 (ENOD11) expression and does so through competitive inhibition of ERF Required for Nodulation (ERN1). In contrast, NIN is sufficient to promote the expression of the cytokinin receptor Cytokinin Response 1 (CRE1), which is restricted to the root cortex. Our work in Medicago truncatula highlights the complexity of NIN action and places NIN as a central player in the coordination of the symbiotic developmental programs occurring in differing tissues of the root that combined are necessary for a nitrogen-fixing symbiosis. PMID:26672071

  20. Multiple Autoregulation of Nodulation (AON) Signals Identified through Split Root Analysis of Medicago truncatula sunn and rdn1 Mutants.

    Science.gov (United States)

    Kassaw, Tessema; Jr, William Bridges; Frugoli, Julia

    2015-04-27

    Nodulation is energetically costly to the host: legumes balance the nitrogen demand with the energy expense by limiting the number of nodules through long-distance signaling. A split root system was used to investigate systemic autoregulation of nodulation (AON) in Medicago truncatula and the role of the AON genes RDN1 and SUNN in the regulatory circuit. Developing nodule primordia did not trigger AON in plants carrying mutations in RDN1 and SUNN genes, while wild type plants had fully induced AON within three days. However, despite lacking an early suppression response, AON mutants suppressed nodulation when roots were inoculated 10 days or more apart, correlated with the maturation of nitrogen fixing nodules. In addition to correlation between nitrogen fixation and suppression of nodulation, suppression by extreme nutrient stress was also observed in all genotypes and may be a component of the observed response due to the conditions of the assay. These results suggest there is more than one systemic regulatory circuit controlling nodulation in M. truncatula. While both signals are present in wild type plants, the second signal can only be observed in plants lacking the early repression (AON mutants). RDN1 and SUNN are not essential for response to the later signal.

  1. Elevated CO(2 modifies N acquisition of Medicago truncatula by enhancing N fixation and reducing nitrate uptake from soil.

    Directory of Open Access Journals (Sweden)

    Huijuan Guo

    Full Text Available The effects of elevated CO2 (750 ppm vs. 390 ppm were evaluated on nitrogen (N acquisition and assimilation by three Medicago truncatula genotypes, including two N-fixing-deficient mutants (dnf1-1 and dnf1-2 and their wild-type (Jemalong. The proportion of N acquisition from atmosphere and soil were quantified by (15N stable isotope, and N transportation and assimilation-related genes and enzymes were determined by qPCR and biochemical analysis. Elevated CO2 decreased nitrate uptake from soil in all three plant genotypes by down-regulating nitrate reductase (NR, nitrate transporter NRT1.1 and NR activity. Jemalong plant, however, produced more nodules, up-regulated N-fixation-related genes and enhanced percentage of N derived from fixation (%Ndf to increase foliar N concentration and N content in whole plant (Ntotal Yield to satisfy the requirement of larger biomass under elevated CO2. In contrast, both dnf1 mutants deficient in N fixation consequently decreased activity of glutamine synthetase/glutamate synthase (GS/GOGAT and N concentration under elevated CO2. Our results suggest that elevated CO2 is likely to modify N acquisition of M. truncatula by simultaneously increasing N fixation and reducing nitrate uptake from soil. We propose that elevated CO2 causes legumes to rely more on N fixation than on N uptake from soil to satisfy N requirements.

  2. DASH transcription factor impacts Medicago truncatula seed size by its action on embryo morphogenesis and auxin homeostasis.

    Science.gov (United States)

    Noguero, Mélanie; Le Signor, Christine; Vernoud, Vanessa; Bandyopadhyay, Kaustav; Sanchez, Myriam; Fu, Chunxiang; Torres-Jerez, Ivone; Wen, Jiangqi; Mysore, Kirankumar S; Gallardo, Karine; Udvardi, Michael; Thompson, Richard; Verdier, Jerome

    2015-02-01

    The endosperm plays a pivotal role in the integration between component tissues of molecular signals controlling seed development. It has been shown to participate in the regulation of embryo morphogenesis and ultimately seed size determination. However, the molecular mechanisms that modulate seed size are still poorly understood especially in legumes. DASH (DOF Acting in Seed embryogenesis and Hormone accumulation) is a DOF transcription factor (TF) expressed during embryogenesis in the chalazal endosperm of the Medicago truncatula seed. Phenotypic characterization of three independent dash mutant alleles revealed a role for this TF in the prevention of early seed abortion and the determination of final seed size. Strong loss-of-function alleles cause severe defects in endosperm development and lead to embryo growth arrest at the globular stage. Transcriptomic analysis of dash pods versus wild-type (WT) pods revealed major transcriptional changes and highlighted genes that are involved in auxin transport and perception as mainly under-expressed in dash mutant pods. Interestingly, the exogenous application of auxin alleviated the seed-lethal phenotype, whereas hormonal dosage revealed a much higher auxin content in dash pods compared with WT. Together these results suggested that auxin transport/signaling may be affected in the dash mutant and that aberrant auxin distribution may contribute to the defect in embryogenesis resulting in the final seed size phenotype.

  3. WATER DEFICIT EFFECT ON YIELD AND FORAGE QUALITY OF MEDICAGO SATIVA POPULATIONS UNDER FIELD CONDITIONS IN MARRAKESH AREA (MOROCCO

    Directory of Open Access Journals (Sweden)

    Mohamed FARISSI

    2014-06-01

    Full Text Available The present study focused the effect of water deficit on agronomic potential and some traits related to forage quality in plants of Moroccan Alfalfa (Medicago sativa L. populations (Taf 1, Taf 2, Dem and Tata originated from Oasis and High Atlas of Morocco and an introduced variety from Australia (Siriver. The experiment was conducted under field conditions in experimental station of INRA-Marrakech and under two irrigation treatments. The first treatment was normal irrigation, providing an amount of water corresponding to the potential evapo-transpiration of the crop, and the second treatment was water deficit stress (one irrigation per cut. For each treatment, the experiment was conducted as a split plot based on a randomized complete block design with four replications. The plants were measured and analyzed over three cuts. Some agronomic traits as, plant height, fresh and dry forage yields were measured. The forage quality was evaluated by leaf:stem ratio and the contents of plants in proteins and nitrogen. The results indicated that the water deficit has negatively affected the plant height and forage yield. The decrease in leaf:stem ratio was observed under water deficit conditions. However, the proteins and nitrogen contents were unaffected. The behavior of tested alfalfa genotypes was significantly different. The Moroccan alfalfa populations were more adapted to water deficit conditions comparatively to Siriver variety and the Tata population was the most adapted one.

  4. Allelopathic Potential of Switchgrass ( Panicum virgatum L.) on Perennial Ryegrass ( Lolium perenne L.) and Alfalfa ( Medicago sativa L.)

    Science.gov (United States)

    Shui, Junfeng; An, Yu; Ma, Yongqing; Ichizen, Nobumasa

    2010-10-01

    This study investigated allelopathy and its chemical basis in nine switchgrass ( Panicum virgatum L.) accessions. Perennial ryegrass ( Lolium perenne L.) and alfalfa ( Medicago sativa L.) were used as test species. Undiluted aqueous extracts (5 g plant tissue in 50 ml water) from the shoots and roots of most of the switchgrass accessions inhibited the germination and growth of the test species. However, the allelopathic effect of switchgrass declined when extracts were diluted 5- or 50-fold. Seedling growth was more sensitive than seed germination as an indicator of allelopathic effect. Allelopathic effect was related to switchgrass ecotype but not related to ploidy level. Upland accessions displayed stronger allelopathic potential than lowland accessions. The aqueous extract from one switchgrass accession was separated into phenols, organic acids, neutral chemicals, and alkaloids, and then these fractions were bioassayed to test for allelopathic potential. Alkaloids had the strongest allelopathic effect among the four chemical fractions. In summary, the results indicated that switchgrass has allelopathic potential; however, there is not enough evidence to conclude that allelopathic advantage is the main factor that has contributed to the successful establishment of switchgrass on China’s Loess Plateau.

  5. Henkin and Hybrid Logic

    DEFF Research Database (Denmark)

    Blackburn, Patrick Rowan; Huertas, Antonia; Manzano, Maria;

    2014-01-01

    Leon Henkin was not a modal logician, but there is a branch of modal logic that has been deeply influenced by his work. That branch is hybrid logic, a family of logics that extend orthodox modal logic with special proposition symbols (called nominals) that name worlds. This paper explains why...... Henkin’s techniques are so important in hybrid logic. We do so by proving a completeness result for a hybrid type theory called HTT, probably the strongest hybrid logic that has yet been explored. Our completeness result builds on earlier work with a system called BHTT, or basic hybrid type theory...... is due to the first-order perspective, which lies at the heart of Henin’s best known work and hybrid logic....

  6. BSA Hybrid Synthesized Polymer

    Institute of Scientific and Technical Information of China (English)

    Zong Bin LIU; Xiao Pei DENG; Chang Sheng ZHAO

    2006-01-01

    Bovine serum albumin (BSA), a naturally occurring biopolymer, was regarded as a polymeric material to graft to an acrylic acid (AA)-N-vinyl pyrrolidone (NVP) copolymer to form a biomacromolecular hybrid polymer. The hybrid polymer can be blended with polyethersulfone (PES) to increase the hydrophilicity of the PES membrane, which suggested that the hybrid polymer might have a wide application in the modification of biomaterials.

  7. Hybrid Action Systems

    DEFF Research Database (Denmark)

    Ronkko, Mauno; Ravn, Anders P.

    1997-01-01

    a differential action, which allows differential equations as primitive actions. The extension allows us to model hybrid systems with both continuous and discrete behaviour. The main result of this paper is an extension of such a hybrid action system with parallel composition. The extension does not change...... the original meaning of the parallel composition, and therefore also the ordinary action systems can be composed in parallel with the hybrid action systems....

  8. HYBRID VEHICLE CONTROL SYSTEM

    Directory of Open Access Journals (Sweden)

    V. Dvadnenko

    2016-06-01

    Full Text Available The hybrid vehicle control system includes a start–stop system for an internal combustion engine. The system works in a hybrid mode and normal vehicle operation. To simplify the start–stop system, there were user new possibilities of a hybrid car, which appeared after the conversion. Results of the circuit design of the proposed system of basic blocks are analyzed.

  9. Nanoscale Organic Hybrid Electrolytes

    KAUST Repository

    Nugent, Jennifer L.

    2010-08-20

    Nanoscale organic hybrid electrolytes are composed of organic-inorganic hybrid nanostructures, each with a metal oxide or metallic nanoparticle core densely grafted with an ion-conducting polyethylene glycol corona - doped with lithium salt. These materials form novel solvent-free hybrid electrolytes that are particle-rich, soft glasses at room temperature; yet manifest high ionic conductivity and good electrochemical stability above 5V. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Hybrid radiator cooling system

    Science.gov (United States)

    France, David M.; Smith, David S.; Yu, Wenhua; Routbort, Jules L.

    2016-03-15

    A method and hybrid radiator-cooling apparatus for implementing enhanced radiator-cooling are provided. The hybrid radiator-cooling apparatus includes an air-side finned surface for air cooling; an elongated vertically extending surface extending outwardly from the air-side finned surface on a downstream air-side of the hybrid radiator; and a water supply for selectively providing evaporative cooling with water flow by gravity on the elongated vertically extending surface.

  11. Hybrid Unifying Variable Supernetwork Model

    Institute of Scientific and Technical Information of China (English)

    LIU; Qiang; FANG; Jin-qing; LI; Yong

    2015-01-01

    In order to compare new phenomenon of topology change,evolution,hybrid ratio and network characteristics of unified hybrid network theoretical model with unified hybrid supernetwork model,this paper constructed unified hybrid variable supernetwork model(HUVSM).The first layer introduces a hybrid ratio dr,the

  12. Large Unifying Hybrid Supernetwork Model

    Institute of Scientific and Technical Information of China (English)

    LIU; Qiang; FANG; Jin-qing; LI; Yong

    2015-01-01

    For depicting multi-hybrid process,large unifying hybrid network model(so called LUHNM)has two sub-hybrid ratios except dr.They are deterministic hybrid ratio(so called fd)and random hybrid ratio(so called gr),respectively.

  13. Three Medicago MtFUL genes have distinct and overlapping expression patterns during vegetative and reproductive development and 35S:MtFULb accelerates flowering and causes a terminal flower phenotype in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Mauren eJaudal

    2015-02-01

    Full Text Available The timing of the transition to flowering is carefully controlled by plants in order to optimise sexual reproduction and the ensuing production of seeds, grains and fruits. The genetic networks that regulate floral induction are best characterised in the temperate eudicot Arabidopsis in which the florigen gene FT plays a major role in promoting the transition to flowering. Legumes are an important plant group, but less is known about the regulation of their flowering time. In the model legume Medicago truncatula (Medicago, a temperate annual plant like Arabidopsis, flowering is induced by prolonged cold (vernalisation followed by long day lengths (LD. Recent molecular-genetic experiments have revealed that a FT-like gene, MtFTa1, is a central regulator of flowering time in Medicago. Here, we characterize the three Medicago FRUITFULL (FUL MADS transcription factors, MtFULa, MtFULb and MtFULc using phylogenetic analyses, gene expression profiling through developmental time courses, and functional analyses in transgenic plants. MtFULa and MtFULb have similarity in sequence and expression profiles under inductive environmental conditions during both vegetative and reproductive development while MtFULc is only up regulated in the apex after flowering in LD conditions. Sustained up regulation of MtFULs requires functional MtFTa1 but their transcript levels are not affected during cold treatment. Overexpression of MtFULa and MtFULb promotes flowering in transgenic Arabidopsis plants with an additional terminal flower phenotype on some 35S:MtFULb plants. An increase in transcript levels of the MtFULs was also observed in Medicago plants overexpressing MtFTa1. Our results suggest that the MtFULs are targets of MtFTa1. Overall, this work highlights the conserved functions of FUL-like genes in promoting flowering and other roles in plant development and thus contributes to our understanding of the genetic control of the flowering process in Medicago.

  14. Hybrid Rocket Technology

    National Research Council Canada - National Science Library

    Sankaran Venugopal; K K Rajesh; V Ramanujachari

    2011-01-01

    With their unique operational characteristics, hybrid rockets can potentially provide safer, lower-cost avenues for spacecraft and missiles than the current solid propellant and liquid propellant systems...

  15. Hybrid FOSS Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Armstrong researchers are continuing their efforts to further develop FOSS technologies. A hybrid FOSS technique (HyFOSS) employs conventional continuous grating...

  16. From hybrid swarms to swarms of hybrids

    Science.gov (United States)

    Stohlgren, Thomas J.; Szalanski, Allen L; Gaskin, John F.; Young, Nicholas E.; West, Amanda; Jarnevich, Catherine S.; Tripodi, Amber

    2015-01-01

    Science has shown that the introgression or hybridization of modern humans (Homo sapiens) with Neanderthals up to 40,000 YBP may have led to the swarm of modern humans on earth. However, there is little doubt that modern trade and transportation in support of the humans has continued to introduce additional species, genotypes, and hybrids to every country on the globe. We assessed the utility of species distributions modeling of genotypes to assess the risk of current and future invaders. We evaluated 93 locations of the genus Tamarix for which genetic data were available. Maxent models of habitat suitability showed that the hybrid, T. ramosissima x T. chinensis, was slightly greater than the parent taxa (AUCs > 0.83). General linear models of Africanized honey bees, a hybrid cross of Tanzanian Apis mellifera scutellata and a variety of European honey bee including A. m. ligustica, showed that the Africanized bees (AUC = 0.81) may be displacing European honey bees (AUC > 0.76) over large areas of the southwestern U.S. More important, Maxent modeling of sub-populations (A1 and A26 mitotypes based on mDNA) could be accurately modeled (AUC > 0.9), and they responded differently to environmental drivers. This suggests that rapid evolutionary change may be underway in the Africanized bees, allowing the bees to spread into new areas and extending their total range. Protecting native species and ecosystems may benefit from risk maps of harmful invasive species, hybrids, and genotypes.

  17. Genome-wide identification and expression profiling analysis of the Aux/IAA gene family in Medicago truncatula during the early phase of Sinorhizobium meliloti infection.

    Directory of Open Access Journals (Sweden)

    Chenjia Shen

    Full Text Available BACKGROUND: Auxin/indoleacetic acid (Aux/IAA genes, coding a family of short-lived nuclear proteins, play key roles in wide variety of plant developmental processes, including root system regulation and responses to environmental stimulus. However, how they function in auxin signaling pathway and symbiosis with rhizobial in Medicago truncatula are largely unknown. The present study aims at gaining deeper insight on distinctive expression and function features of Aux/IAA family genes in Medicago truncatula during nodule formation. PRINCIPAL FINDINGS: Using the latest updated draft of the full Medicago truncatula genome, a comprehensive identification and analysis of IAA genes were performed. The data indicated that MtIAA family genes are distributed in all the M. truncatula chromosomes except chromosome 6. Most of MtIAA genes are responsive to exogenous auxin and express in tissues-specific manner. To understand the biological functions of MtIAA genes involved in nodule formation, quantitative real-time polymerase chain reaction (qRT-PCR was used to test the expression profiling of MtIAA genes during the early phase of Sinorhizobium meliloti (S. meliloti infection. The expression patterns of most MtIAA genes were down-regulated in roots and up-regulated in shoots by S. meliloti infection. The differences in expression responses between roots and shoots caused by S. meliloti infection were alleviated by 1-NOA application. CONCLUSION: The genome-wide identification, evolution and expression pattern analysis of MtIAA genes were performed in this study. The data helps us to understand the roles of MtIAA-mediated auxin signaling in nodule formation during the early phase of S. meliloti infection.

  18. Aphanomyces euteiches cell wall fractions containing novel glucan-chitosaccharides induce defense genes and nuclear calcium oscillations in the plant host Medicago truncatula.

    Directory of Open Access Journals (Sweden)

    Amaury Nars

    Full Text Available N-acetylglucosamine-based saccharides (chitosaccharides are components of microbial cell walls and act as molecular signals during host-microbe interactions. In the legume plant Medicago truncatula, the perception of lipochitooligosaccharide signals produced by symbiotic rhizobia and arbuscular mycorrhizal fungi involves the Nod Factor Perception (NFP lysin motif receptor-like protein and leads to the activation of the so-called common symbiotic pathway. In rice and Arabidopsis, lysin motif receptors are involved in the perception of chitooligosaccharides released by pathogenic fungi, resulting in the activation of plant immunity. Here we report the structural characterization of atypical chitosaccharides from the oomycete pathogen Aphanomyces euteiches, and their biological activity on the host Medicago truncatula. Using a combination of biochemical and biophysical approaches, we show that these chitosaccharides are linked to β-1,6-glucans, and contain a β-(1,3;1,4-glucan backbone whose β-1,3-linked glucose units are substituted on their C-6 carbon by either glucose or N-acetylglucosamine residues. This is the first description of this type of structural motif in eukaryotic cell walls. Glucan-chitosaccharide fractions of A. euteiches induced the expression of defense marker genes in Medicago truncatula seedlings independently from the presence of a functional Nod Factor Perception protein. Furthermore, one of the glucan-chitosaccharide fractions elicited calcium oscillations in the nucleus of root cells. In contrast to the asymmetric oscillatory calcium spiking induced by symbiotic lipochitooligosaccharides, this response depends neither on the Nod Factor Perception protein nor on the common symbiotic pathway. These findings open new perspectives in oomycete cell wall biology and elicitor recognition and signaling in legumes.

  19. 紫花苜蓿茎尖离体再生体系的建立%Establishment of Vitro Regeneration System in Medicago sativa Stem Tip

    Institute of Scientific and Technical Information of China (English)

    郭永霞; 孙强; 王丽艳; 荆瑞勇; 殷奎德

    2013-01-01

    以紫花苜蓿的成熟种子为外植体,以组培苗茎尖为材料建立了紫花苜蓿离体再生体系。研究结果显示:紫花苜蓿茎尖分化增殖的最佳培养基为MS+6-BA1.5 mg·L-1+NAA0.1 mg·L-1,平均增殖系数为6.25;最适生根培养基为MS+IBA0.05 mg·L-1,平均侧根数为28.5条,生根率达到93.5%。该再生体系的建立为紫花苜蓿遗传转化后转基因植株的快速繁殖奠定了基础。%A vitro regeneration system was established using the stem tip of tissue seedling as the material and the ripe seeds of Medicago sativa L. were used as explants. The results showed that MS with 6-BA1.5 mg·L-1+NAA0.1 mg·L-1 was the optimal medium for differentiation and proliferation of stem tip in Medicago sativa L.,and average proliferation coefficient was 6.25;MS with IBA 0.05 mg·L -1 was the optimal rooting medium,and the average side root number and the rooting rate respectively was 28.5,93.5%. The establishment of the regeneration system provided a foundation for genetic transformation and rapid propagation of Medicago sativa L.

  20. Fotossíntese em alfafa (Medicago sativa L. sob supressão e ressuprimento de fosfato Photosynthesis in alfalfa (Medicago sativa L. under phosphate suppression and ressuply

    Directory of Open Access Journals (Sweden)

    Fernando Teixeira Gomes

    2003-10-01

    Full Text Available Neste estudo, foram avaliados os efeitos da supressão e do ressuprimento de fosfato (Pi sobre a fotossíntese e eficiência fotoquímica de plantas de Medicago sativa cv. Flórida 77, em diferentes estádios do desenvolvimento vegetativo (V3, V4 e reprodutivo (R6, R8. O ensaio foi conduzido em casa de vegetação e as plantas cultivadas na solução nutritiva de HOAGLAND & ARNON (1950, contendo 0,14mmol L-1 de Pi. A supressão de Pi por dez dias reduziu os teores de fósforo nas folhas amostradas, em todos os estádios do desenvolvimento. Entretanto, com o ressuprimento, somente nos estádios vegetativos, os valores foram semelhantes ao tratamento controle. A fotossíntese por área foliar, em todos os estádios do desenvolvimento diminuiu com a supressão de Pi. De modo geral, o ressuprimento de Pi à solução nutritiva resultou em recuperação na fotossíntese, excetuando-se as plantas no estádio V3, uma indicação de que o período de supressão não causou danos permanentes no aparato fotossintético. Os teores dos pigmentos fotossintéticos e a eficiência fotoquímica do fotossistema II (FS II, avaliada pela relação Fv/Fm, não foram alterados quando as plantas foram submetidas à supressão de Pi. Esse resultado demonstra que o transporte de elétrons através do FS II não limitou a fotossíntese nas folhas amostradas, sob supressão de Pi, sugerindo que a supressão causou efeito mais pronunciado na etapa bioquímica da fotossíntese.This work evaluated the phosphate (Pi suppression and ressupply on photosynthesis and photochemical efficiency from Medicago sativa plants cv. Florida 77, in different growth stages (V3 and V4 and reproductive (R6 and R8. The experiment was performed in a greenhouse, the plants being cultivated in HOAGLAND & ARMOND (1950 nutritive solution containing 0,14mmol L-1 of Pi. Pi suppression for ten days reduced Pi levels in sampled leaves, in all growth stages. However, with the re-supply only in the

  1. Respuestas morfológicas y fisiológicas de Rhizophagus intraradices y Medicago sativa ante contaminación por diésel.

    OpenAIRE

    Hernández Ortega, Herminia Alejandra

    2014-01-01

    Este estudio evaluó el crecimiento, cambios morfológicos, actividades fisiológicas y expresión de genes en Medicago sativa en respuesta al estrés por la contaminación con diésel, y por la inoculación del hongo micorrízico arbuscular Rhizophagus intraradices. Este trabajo fue dividido en cuatro capítulos que describen cuatro diferentes fases experimentales. El primer capítulo describe el efecto del diésel en el desarrollo y colonización de R. intraradices. El segundo capítulo presenta resultad...

  2. Resistance and susceptibility of alfalfa (Medicago sativa L.) cultivars to the aphid Therioaphis maculata (Homoptera:Aphididae): insect biology and cultivar evaluation

    Institute of Scientific and Technical Information of China (English)

    ALEXANDRE DE ALMEIDA E SILVA; ELENICE MOURO VARANDA; JOS(E) RICARDO BAROSELA

    2006-01-01

    Biology of the aphid Therioaphis maculata was studied on alfalfa (Medicago sativa L.), including four resistant (Mesa-Sirsa, CUF101, Baker and Lahontan) and two susceptible (ARC and Caliverde) alfalfa cultivars, and one of the most cropped Brazilian cultivars, Crioula. Under controlled conditions, antibiosis (i.e., reduced longevity, fecundity and increased mortality of the aphid) was observed mainly on the resistant alfalfa cultivars,except on Lahontan. Crioula seemed to be tolerant to aphids. Present data support geographic limitation usage of cultivars, and we suggest Baker and Mesa-Sirsa as sources of antibiosis,and provide biological information of a tropical T. maculata biotype on alfalfa.

  3. Regulating Alfalfa (Medicago Sativa L.) Vegetative and Reproductive Growth%紫花苜蓿营养生长与生殖生长调控

    Institute of Scientific and Technical Information of China (English)

    杜文华; 曹致中

    2005-01-01

    主要研究了播种行距,灌水量,N、P、K肥施用量,植物生长延缓剂,微肥,干燥剂对甘农3号紫花苜蓿(Medicago sativa L.CV.Gannong No·3)(下简称苜蓿)营养生长和生殖生长的影响,及其种群的生长冗余。结果表明。

  4. Varianza genética y mapeo molecular de rendimiento y calidad nutricional en familias de medios hermanos en Medicago sativa.

    OpenAIRE

    Galicia Juárez, Marisol

    2012-01-01

    La alfalfa (Medicago sativa L.) es considerada como el cultivo forrajero de mayor importancia en la nutrición de animales domésticos, y se siembra en todo el mundo. A pesar de existir una amplia gama de variedades de alfalfa sembradas en México hay pocos estudios acerca de la variabilidad genética dentro y entre poblaciones criollas, por tanto esta investigación tuvo el objetivo de estimar la variabilidad genética de caracteres cuantitativos agronómicos y de calidad de nutrientes consideran...

  5. Cardiac hybrid imaging

    Energy Technology Data Exchange (ETDEWEB)

    Gaemperli, Oliver [University Hospital Zurich, Cardiac Imaging, Zurich (Switzerland); University Hospital Zurich, Nuclear Cardiology, Cardiovascular Center, Zurich (Switzerland); Kaufmann, Philipp A. [University Hospital Zurich, Cardiac Imaging, Zurich (Switzerland); Alkadhi, Hatem [University Hospital Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland)

    2014-05-15

    Hybrid cardiac single photon emission computed tomography (SPECT)/CT imaging allows combined assessment of anatomical and functional aspects of cardiac disease. In coronary artery disease (CAD), hybrid SPECT/CT imaging allows detection of coronary artery stenosis and myocardial perfusion abnormalities. The clinical value of hybrid imaging has been documented in several subsets of patients. In selected groups of patients, hybrid imaging improves the diagnostic accuracy to detect CAD compared to the single imaging techniques. Additionally, this approach facilitates functional interrogation of coronary stenoses and guidance with regard to revascularization procedures. Moreover, the anatomical information obtained from CT coronary angiography or coronary artery calcium scores (CACS) adds prognostic information over perfusion data from SPECT. The use of cardiac hybrid imaging has been favoured by the dissemination of dedicated hybrid systems and the release of dedicated image fusion software, which allow simple patient throughput for hybrid SPECT/CT studies. Further technological improvements such as more efficient detector technology to allow for low-radiation protocols, ultra-fast image acquisition and improved low-noise image reconstruction algorithms will be instrumental to further promote hybrid SPECT/CT in research and clinical practice. (orig.)

  6. Hybrid intelligent engineering systems

    CERN Document Server

    Jain, L C; Adelaide, Australia University of

    1997-01-01

    This book on hybrid intelligent engineering systems is unique, in the sense that it presents the integration of expert systems, neural networks, fuzzy systems, genetic algorithms, and chaos engineering. It shows that these new techniques enhance the capabilities of one another. A number of hybrid systems for solving engineering problems are presented.

  7. A Hybrid Imagination

    DEFF Research Database (Denmark)

    Jamison, Andrew; Christensen, Steen Hyldgaard; Botin, Lars

    contexts, or sites, for mixing scientific knowledge and technical skills from different fields and social domains into new combinations, thus fostering what the authors term a “hybrid imagination”. Such a hybrid imagination is especially important today, as a way to counter the competitive and commercial...

  8. Hybrid trajectory spaces

    NARCIS (Netherlands)

    Collins, P.J.

    2005-01-01

    In this paper, we present a general framework for describing and studying hybrid systems. We represent the trajectories of the system as functions on a hybrid time domain, and the system itself by its trajectory space, which is the set of all possible trajectories. The trajectory space is given a na

  9. Editorial: Hybrid Systems

    DEFF Research Database (Denmark)

    Olderog, Ernst-Rüdiger; Ravn, Anders Peter

    2007-01-01

    An introduction to three papers in a special issue on Hybrid Systems. These paper were first presented at an IFIP WG 2.2 meeting in Skagen 2005.......An introduction to three papers in a special issue on Hybrid Systems. These paper were first presented at an IFIP WG 2.2 meeting in Skagen 2005....

  10. Hybrid reactors. [Fuel cycle

    Energy Technology Data Exchange (ETDEWEB)

    Moir, R.W.

    1980-09-09

    The rationale for hybrid fusion-fission reactors is the production of fissile fuel for fission reactors. A new class of reactor, the fission-suppressed hybrid promises unusually good safety features as well as the ability to support 25 light-water reactors of the same nuclear power rating, or even more high-conversion-ratio reactors such as the heavy-water type. One 4000-MW nuclear hybrid can produce 7200 kg of /sup 233/U per year. To obtain good economics, injector efficiency times plasma gain (eta/sub i/Q) should be greater than 2, the wall load should be greater than 1 MW.m/sup -2/, and the hybrid should cost less than 6 times the cost of a light-water reactor. Introduction rates for the fission-suppressed hybrid are usually rapid.

  11. Hybrid propulsion technology program

    Science.gov (United States)

    1990-01-01

    Technology was identified which will enable application of hybrid propulsion to manned and unmanned space launch vehicles. Two design concepts are proposed. The first is a hybrid propulsion system using the classical method of regression (classical hybrid) resulting from the flow of oxidizer across a fuel grain surface. The second system uses a self-sustaining gas generator (gas generator hybrid) to produce a fuel rich exhaust that was mixed with oxidizer in a separate combustor. Both systems offer cost and reliability improvement over the existing solid rocket booster and proposed liquid boosters. The designs were evaluated using life cycle cost and reliability. The program consisted of: (1) identification and evaluation of candidate oxidizers and fuels; (2) preliminary evaluation of booster design concepts; (3) preparation of a detailed point design including life cycle costs and reliability analyses; (4) identification of those hybrid specific technologies needing improvement; and (5) preperation of a technology acquisition plan and large scale demonstration plan.

  12. Influencia del estado de madurez a cosecha sobre la calidad de semillas de alfalfa (Medicago sativa L.

    Directory of Open Access Journals (Sweden)

    RENZI, J.P

    2011-12-01

    Full Text Available ResumenLa alfalfa (Medicago sativa L. recién cosechada presenta dormición física debida a la dureza de sus tegumentos que puede afectar la producción de forraje en el primer año de implantación. Aunque se conoce que la temperatura y la humedad durante la fructificación son factores exógenos asociados a la dureza, se desconoce el efecto del grado de madurez a cosecha sobre la calidad de las semillas de alfalfa. Se recolectaron vainas en diferentes estados de madurez al inicio y en el fin de la fructificación de lotes comerciales de multiplicación de semilla de alfalfa del Valle Bonaerense del Río Colorado (VBRC. Al finalizar la estación de crecimiento, se realizaron pruebas de calidad, incluyendo la dureza de semilla. La cosecha a partir de vainas amarillas produjo los mayores valores de poder germinativo (plántulas normales + semillas duras. La recolección en vainas verdes aumentó el porcentaje de semillas muertas y plántulas anormales. Se observaron altos valores de dureza asociados a la cosecha con vainas amarillas que bajaron con la recolección en el estado de vainas marrones. Las vainas marrones del tercio superior del canopeo originaron semillas más duras que la de los estratos inferiores, posiblemente porque estas últimas estuvieron expuestas a un mayor período con fluctuaciones ambientales que habrían acelerado la pérdida de la dureza por envejecimiento.AbstractAlfalfa (Medicago sativa L. seed recently harvested have high physical dormancy (hard seeds, which can affect forage production in the first year of establishment. Although it is know that the temperature, air moisture and water stress are exogenous factors associated with the hard seed, there are few information about the effects of harvest maturity stages on germination and physical dormancy of alfalfa. The study was conducted on commercial lots of alfalfa seed multiplication of the Colorado River Valley Bonaerense (VBRC. The pods were hand harvested at

  13. MsZEP, a novel zeaxanthin epoxidase gene from alfalfa (Medicago sativa), confers drought and salt tolerance in transgenic tobacco.

    Science.gov (United States)

    Zhang, Zhiqiang; Wang, Yafang; Chang, Leqin; Zhang, Tong; An, Jie; Liu, Yushi; Cao, Yuman; Zhao, Xia; Sha, Xuyang; Hu, Tianming; Yang, Peizhi

    2016-02-01

    The zeaxanthin epoxidase gene ( MsZEP ) was cloned and characterized from alfalfa and validated for its function of tolerance toward drought and salt stresses by heterologous expression in Nicotiana tabacum. Zeaxanthin epoxidase (ZEP) plays important roles in plant response to various environment stresses due to its functions in ABA biosynthetic and the xanthophyll cycle. To understand the expression characteristics and the biological functions of ZEP in alfalfa (Medicago sativa), a novel gene, designated as MsZEP (KM044311), was cloned, characterized and overexpressed in Nicotiana tabacum. The open reading frame of MsZEP contains 1992 bp nucleotides and encodes a 663-amino acid polypeptide. Amino acid sequence alignment indicated that deduced MsZEP protein was highly homologous to other plant ZEP sequences. Phylogenetic analysis showed that MsZEP was grouped into a branch with other legume plants. Real-time quantitative PCR revealed that MsZEP gene expression was clearly tissue-specific, and the expression levels were higher in green tissues (leaves and stems) than in roots. MsZEP expression decreased in shoots under drought, cold, heat and ABA treatment, while the expression levels in roots showed different trends. Besides, the results showed that nodules could up-regulate the MsZEP expression under non-stressful conditions and in the earlier stage of different abiotic stress. Heterologous expression of the MsZEP gene in N. tabacum could confer tolerance to drought and salt stress by affecting various physiological pathways, ABA levels and stress-responsive genes expression. Taken together, these results suggested that the MsZEP gene may be involved in alfalfa responses to different abiotic stresses and nodules, and could enhance drought and salt tolerance of transgenic tobacco by heterologous expression.

  14. The structures of cytosolic and plastid-located glutamine synthetases from Medicago truncatula reveal a common and dynamic architecture

    Energy Technology Data Exchange (ETDEWEB)

    Torreira, Eva [Centro de Investigaciones Biológicas – CSIC, Ramiro de Maeztu 9, 28040 Madrid (Spain); Seabra, Ana Rita [IBMC – Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto (Portugal); Marriott, Hazel; Zhou, Min [University of Oxford, South Parks Road, Oxford OX1 3QZ (United Kingdom); Llorca, Óscar [Centro de Investigaciones Biológicas – CSIC, Ramiro de Maeztu 9, 28040 Madrid (Spain); Robinson, Carol V. [University of Oxford, South Parks Road, Oxford OX1 3QZ (United Kingdom); Carvalho, Helena G. [IBMC – Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto (Portugal); Fernández-Tornero, Carlos, E-mail: cftornero@cib.csic.es [Centro de Investigaciones Biológicas – CSIC, Ramiro de Maeztu 9, 28040 Madrid (Spain); Pereira, Pedro José Barbosa, E-mail: cftornero@cib.csic.es [IBMC – Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto (Portugal); Centro de Investigaciones Biológicas – CSIC, Ramiro de Maeztu 9, 28040 Madrid (Spain)

    2014-04-01

    The experimental models of dicotyledonous cytoplasmic and plastid-located glutamine synthetases unveil a conserved eukaryotic-type decameric architecture, with subtle structural differences in M. truncatula isoenzymes that account for their distinct herbicide resistance. The first step of nitrogen assimilation in higher plants, the energy-driven incorporation of ammonia into glutamate, is catalyzed by glutamine synthetase. This central process yields the readily metabolizable glutamine, which in turn is at the basis of all subsequent biosynthesis of nitrogenous compounds. The essential role performed by glutamine synthetase makes it a prime target for herbicidal compounds, but also a suitable intervention point for the improvement of crop yields. Although the majority of crop plants are dicotyledonous, little is known about the structural organization of glutamine synthetase in these organisms and about the functional differences between the different isoforms. Here, the structural characterization of two glutamine synthetase isoforms from the model legume Medicago truncatula is reported: the crystallographic structure of cytoplasmic GSII-1a and an electron cryomicroscopy reconstruction of plastid-located GSII-2a. Together, these structural models unveil a decameric organization of dicotyledonous glutamine synthetase, with two pentameric rings weakly connected by inter-ring loops. Moreover, rearrangement of these dynamic loops changes the relative orientation of the rings, suggesting a zipper-like mechanism for their assembly into a decameric enzyme. Finally, the atomic structure of M. truncatula GSII-1a provides important insights into the structural determinants of herbicide resistance in this family of enzymes, opening new avenues for the development of herbicide-resistant plants.

  15. Occurrence of Transgenic Feral Alfalfa (Medicago sativa subsp. sativa L. in Alfalfa Seed Production Areas in the United States.

    Directory of Open Access Journals (Sweden)

    Stephanie L Greene

    Full Text Available The potential environmental risks of transgene exposure are not clear for alfalfa (Medicago sativa subsp. sativa, a perennial crop that is cross-pollinated by insects. We gathered data on feral alfalfa in major alfalfa seed-production areas in the western United States to (1 evaluate evidence that feral transgenic plants spread transgenes and (2 determine environmental and agricultural production factors influencing the location of feral alfalfa, especially transgenic plants. Road verges in Fresno, California; Canyon, Idaho; and Walla Walla, Washington were surveyed in 2011 and 2012 for feral plants, and samples were tested for the CP4 EPSPS protein that conveys resistance to glyphosate. Of 4580 sites surveyed, feral plants were observed at 404 sites. Twenty-seven percent of these sites had transgenic plants. The frequency of sites having transgenic feral plants varied among our study areas. Transgenic plants were found in 32.7%, 21.4.7% and 8.3% of feral plant sites in Fresno, Canyon and Walla Walla, respectively. Spatial analysis suggested that feral populations started independently and tended to cluster in seed and hay production areas, places where seed tended to drop. Significant but low spatial auto correlation suggested that in some instances, plants colonized nearby locations. Neighboring feral plants were frequently within pollinator foraging range; however, further research is needed to confirm transgene flow. Locations of feral plant clusters were not well predicted by environmental and production variables. However, the likelihood of seed spillage during production and transport had predictive value in explaining the occurrence of transgenic feral populations. Our study confirms that genetically engineered alfalfa has dispersed into the environment, and suggests that minimizing seed spillage and eradicating feral alfalfa along road sides would be effective strategies to minimize transgene dispersal.

  16. Arbuscular mycorrhizal colonization alters subcellular distribution and chemical forms of cadmium in Medicago sativa L. and resists cadmium toxicity.

    Directory of Open Access Journals (Sweden)

    Yuanpeng Wang

    Full Text Available Some plants can tolerate and even detoxify soils contaminated with heavy metals. This detoxification ability may depend on what chemical forms of metals are taken up by plants and how the plants distribute the toxins in their tissues. This, in turn, may have an important impact on phytoremediation. We investigated the impact of arbuscular mycorrhizal (AM fungus, Glomus intraradices, on the subcellular distribution and chemical forms of cadmium (Cd in alfalfa (Medicago sativa L. that were grown in Cd-added soils. The fungus significantly colonized alfalfa roots by day 25 after planting. Colonization of alfalfa by G. intraradices in soils contaminated with Cd ranged from 17% to 69% after 25-60 days and then decreased to 43%. The biomass of plant shoots with AM fungi showed significant 1.7-fold increases compared to no AM fungi addition under the treatment of 20 mg kg(-1 Cd. Concentrations of Cd in the shoots of alfalfa under 0.5, 5, and 20 mgkg(-1 Cd without AM fungal inoculation are 1.87, 2.92, and 2.38 times higher, respectively, than those of fungi-inoculated plants. Fungal inoculation increased Cd (37.2-80.5% in the cell walls of roots and shoots and decreased in membranes after 80 days of incubation compared to untreated plants. The proportion of the inactive forms of Cd in roots was higher in fungi-treated plants than in controls. Furthermore, although fungi-treated plants had less overall Cd in subcellular fragments in shoots, they had more inactive Cd in shoots than did control plants. These results provide a basis for further research on plant-microbe symbioses in soils contaminated with heavy metals, which may potentially help us develop management regimes for phytoremediation.

  17. Drought and Recovery: Independently Regulated Processes Highlighting the Importance of Protein Turnover Dynamics and Translational Regulation in Medicago truncatula.

    Science.gov (United States)

    Lyon, David; Castillejo, Maria Angeles; Mehmeti-Tershani, Vlora; Staudinger, Christiana; Kleemaier, Christoph; Wienkoop, Stefanie

    2016-06-01

    Climate change in conjunction with population growth necessitates a systems biology approach to characterize plant drought acclimation as well as a more thorough understanding of the molecular mechanisms of stress recovery. Plants are exposed to a continuously changing environment. Extremes such as several weeks of drought are followed by rain. This requires a molecular plasticity of the plant enabling drought acclimation and the necessity of deacclimation processes for recovery and continuous growth.During drought stress and subsequent recovery, the metabolome and proteome are regulated through a sequence of molecular processes including synthesis and degradation and molecular interaction networks are part of this regulatory process. In order to study this complex regulatory network, a comprehensive analysis is presented for the first time, investigating protein turnover and regulatory classes of proteins and metabolites during a stress recovery scenario in the model legume Medicago truncatula The data give novel insights into the molecular capacity and differential processes required for acclimation and deacclimation of severe drought stressed plants.Functional cluster and network analyses unraveled independent regulatory mechanisms for stress and recovery with different dynamic phases that during the course of recovery define the plants deacclimation from stress. The combination of relative abundance levels and turnover analysis revealed an early transition phase that seems key for recovery initiation through water resupply and is independent from renutrition. Thus, a first indication for a metabolite and protein-based load capacity was observed necessary for the recovery from drought, an important but thus far ignored possible feature toward tolerance. The data indicate that apart from the plants molecular stress response mechanisms, plasticity may be related to the nutritional status of the plant prior to stress initiation. A new perspective and possible new

  18. Transgenic alfalfa (Medicago sativa) with increased sucrose phosphate synthase activity shows enhanced growth when grown under N2-fixing conditions.

    Science.gov (United States)

    Gebril, Sayed; Seger, Mark; Villanueva, Fabiola Muro; Ortega, Jose Luis; Bagga, Suman; Sengupta-Gopalan, Champa

    2015-10-01

    Overexpression of SPS in alfalfa is accompanied by early flowering, increased plant growth and an increase in elemental N and protein content when grown under N2-fixing conditions. Sucrose phosphate synthase (SPS; EC 2.3.1.14) is the key enzyme in the synthesis of sucrose in plants. The outcome of overexpression of SPS in different plants using transgenic approaches has been quite varied, but the general consensus is that increased SPS activity is associated with the production of new sinks and increased sink strength. In legumes, the root nodule is a strong C sink and in this study our objective was to see how increasing SPS activity in a legume would affect nodule number and function. Here we have transformed alfalfa (Medicago sativa, cv. Regen SY), with a maize SPS gene driven by the constitutive CaMV35S promoter. Our results showed that overexpression of SPS in alfalfa, is accompanied by an increase in nodule number and mass and an overall increase in nitrogenase activity at the whole plant level. The nodules exhibited an increase in the level of key enzymes contributing to N assimilation including glutamine synthetase and asparagine synthetase. Moreover, the stems of the transformants showed higher level of the transport amino acids, Asx, indicating increased export of N from the nodules. The transformants exhibited a dramatic increase in growth both of the shoots and roots, and earlier flowering time, leading to increased yields. Moreover, the transformants showed an increase in elemental N and protein content. The overall conclusion is that increased SPS activity improves the N status and plant performance, suggesting that the availability of more C in the form of sucrose enhances N acquisition and assimilation in the nodules.

  19. Occurrence of Transgenic Feral Alfalfa (Medicago sativa subsp. sativa L.) in Alfalfa Seed Production Areas in the United States.

    Science.gov (United States)

    Greene, Stephanie L; Kesoju, Sandya R; Martin, Ruth C; Kramer, Matthew

    2015-01-01

    The potential environmental risks of transgene exposure are not clear for alfalfa (Medicago sativa subsp. sativa), a perennial crop that is cross-pollinated by insects. We gathered data on feral alfalfa in major alfalfa seed-production areas in the western United States to (1) evaluate evidence that feral transgenic plants spread transgenes and (2) determine environmental and agricultural production factors influencing the location of feral alfalfa, especially transgenic plants. Road verges in Fresno, California; Canyon, Idaho; and Walla Walla, Washington were surveyed in 2011 and 2012 for feral plants, and samples were tested for the CP4 EPSPS protein that conveys resistance to glyphosate. Of 4580 sites surveyed, feral plants were observed at 404 sites. Twenty-seven percent of these sites had transgenic plants. The frequency of sites having transgenic feral plants varied among our study areas. Transgenic plants were found in 32.7%, 21.4.7% and 8.3% of feral plant sites in Fresno, Canyon and Walla Walla, respectively. Spatial analysis suggested that feral populations started independently and tended to cluster in seed and hay production areas, places where seed tended to drop. Significant but low spatial auto correlation suggested that in some instances, plants colonized nearby locations. Neighboring feral plants were frequently within pollinator foraging range; however, further research is needed to confirm transgene flow. Locations of feral plant clusters were not well predicted by environmental and production variables. However, the likelihood of seed spillage during production and transport had predictive value in explaining the occurrence of transgenic feral populations. Our study confirms that genetically engineered alfalfa has dispersed into the environment, and suggests that minimizing seed spillage and eradicating feral alfalfa along road sides would be effective strategies to minimize transgene dispersal.

  20. [Development of Arbuscular Mycorrhiza in Highly Responsive and Mycotrophic Host Plant-Black Medick (Medicago lupulina L.)].

    Science.gov (United States)

    Yurkova, A P; Jacobi, L M; Gapeeva, N E; Stepanova, G V; Shishova, M F

    2015-01-01

    The main phases of arbuscular mycorrhiza (AM) development were analyzed in black medick (Medicago lupulina) with Glomus intraradices. Methods of light and transmission electron microscopy were used to investigate AM. The first mycorrhization was identified on the seventh day after sowing. M. lupulina with AM-fungus Glomus intraradices formed Arum type of AM. Roots of black medick at fruiting stage (on the 88th day) were characterized by the development of forceful mycelium. The thickness of mycelium was comparable with the vascular system of root central cylinder. The development of vesicules into intraradical spores was shown. Micelium, arbuscules, and vesicules developed in close vicinity to the division zone of root tip. This might be evidence of an active symbiotic interaction between partners. All stages of fungal development and breeding, including intraradical spores (in inter-cellular matrix of root cortex), were identified in the roots of black medick, which indicated an active utilization of host plant nutrient substrates by the mycosymbiont. Plant cell cytoplasm extension was identified around young arbuscular branches but not for intracellular hyphae. The presence of active symbiosis was confirmed by increased accumulation of phosphorus in M. lupulina root tissues under conditions of G. intraradices inoculation and low phosphorus level in the soil. Thus, black medick cultivar-population can be characterized as an ecologically obligate mycotrophic plant under conditions of low level of available phosphorus in the soil. Specific features of AM development in intensively mycotrophic black medick, starting from the stage of the first true leaf until host plant fruiting, were evaluated. The obtained plant-microbe system is a perspective model object for further ultracytological and molecular genetic studies of the mechanisms controlling arbuscular mycorrhiza symbiotic efficiency, including selection and investigation of new symbiotic plant mutants.

  1. Nitrogen transfer from forage legumes to grass in a systematic planting design. [Medicago sativa; Lotus corniculatus; Phalaris arundinacea

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    Brophy, L.S.; Heichel, G.H.; Russelle, M.P.

    Alfalfa (Medicago sativa L.) is the most important forage legume in the USA, but N transfer from this or other perennial forage species to companion grasses growing in a mixed sward is poorly understood. Furthermore, interplant distances and legume/grass ratios have seldom been controlled in studies of N transfer from legumes to non-legumes. The objectives of this field study were: (i) to determine the amount of N transferred from alfalfa and birdsfoot trefoil (Lotus carniculatus L.) to reed canarygrass (Phalaris arundinacea L.); (ii) to define conditions of distance and species ratio under which N transfer occurs; (iii) to compare the two legumes for N transfer; and (iv) to determine the effect of grass proximity on legume N/sub 2/ fixation. Legumes were interplanted with grass in single-species rows within km/sup 2/ plots on a Typic hapludoll soil labeled with /sup 15/N. Analysis of herbage showed significantly lower /sup 15/N concentration in grass near legumes than in grass grown alone, and significantly lower /sup 15/N concentration in legumes near grass than legumes in monoculture. Calculations using isotope dilution methods showed that grass derived a maximum of 68% of its N from alfalfa and 79% from trefoil. This N represented 13% of the N/sub 2/ fixed by trefoil and 17% of that fixed by alfalfa. The results indicated that N transfer occurred over a distance of 20 cm with maximum N transfer in areas of high legume/grass ratio. At third harvest, N derived from symbiosis was significantly higher (95% in alfalfa, 92% in trefoil) for legumes grown in mixture with grass than for legumes grown in monoculture (86% in alfalfa, 80% in trefoil). These results indicate that significant N transfer occurred, and that the amount of N transferred was dependent on interspecies distance and legume/grass ratio.

  2. Identification and Analysis of Medicago truncatula Auxin Transporter Gene Families Uncover their Roles in Responses to Sinorhizobium meliloti Infection.

    Science.gov (United States)

    Shen, Chenjia; Yue, Runqing; Bai, Youhuang; Feng, Rong; Sun, Tao; Wang, Xiaofei; Yang, Yanjun; Tie, Shuanggui; Wang, Huizhong

    2015-10-01

    Auxin transport plays a pivotal role in the interaction between legume species and nitrogen-fixing bacteria to form symbioses. Auxin influx carriers auxin resistant 1/like aux 1 (AUX/LAX), efflux carriers pin-formed (PIN) and efflux/conditional P-glycoprotein (PGP/ABCB) are three major protein families participating in auxin polar transport. We used the latest Medicago truncatula genome sequence to characterize and analyze the M. truncatula LAX (MtLAX), M. truncatula PIN (MtPIN) and M. truncatula ABCB (MtABCB) families. Transient expression experiments indicated that three representative auxin transporters (MtLAX3, MtPIN7 and MtABCB1) showed cell plasma membrane localizations. The expression of most MtLAX, MtPIN and MtABCB genes was up-regulated in the roots and was down-regulated in the shoots by Sinorhizobium meliloti infection in the wild type (WT). However, the expression of these genes was down-regulated in both the roots and shoots of an infection-resistant mutant, dmi3. The different expression patterns between the WT and the mutant roots indicated that auxin relocation may be involved in rhizobial infection responses. Furthermore, IAA contents were significantly up-regulated in the shoots and down-regulated in the roots after Sinorhizobium meliloti infection in the WT. Inoculation of roots with rhizobia may reduce the auxin loading from shoots to roots by inhibiting the expression of most auxin transporter genes. However, the rate of change of gene expression and IAA contents in the dmi3 mutant were obviously lower than in the WT. The identification and expression analysis of auxin transporter genes helps us to understand the roles of auxin in the regulation of nodule formation in M. truncatula.

  3. Salicylic acid improves the salinity tolerance of Medicago sativa in symbiosis with Sinorhizobium meliloti by preventing nitrogen fixation inhibition.

    Science.gov (United States)

    Palma, F; López-Gómez, M; Tejera, N A; Lluch, C

    2013-07-01

    In this work we have investigated the contribution of pretreatment with 0.1 and 0.5mM salicylic acid (SA) to the protection against salt stress in root nodules of Medicago sativa in symbiosis with Sinorhizobium meliloti. SA alleviated the inhibition induced by salinity in the plant growth and photosynthetic capacity of M. sativa-S. meliloti symbiosis. In addition, SA prevented the inhibition of the nitrogen fixation capacity under salt stress since nodule biomass was not affected by salinity in SA pretreated plants. Antioxidant enzymes peroxidase (POX), superoxide dismutase (SOD), ascorbate peroxidase (APX), dehidroascorbate reductase (DHAR) and glutathione reductase (GR), key in the main pathway that scavenges H2O2 in plants, were induced by SA pretreatments which suggest that SA may participate in the redox balance in root nodules under salt stress. Catalase activity (CAT) was inhibited around 40% by SA which could be behind the increase of H2O2 detected in nodules of plants pretreated with SA. The accumulation of polyamines (PAs) synthesized in response to salinity was prevented by SA which together with the induction of 1-aminocyclopropane-l-carboxylic acid (ACC) content suggest the prevalence of the ethylene signaling pathway induced by SA in detriment of the synthesis of PAs. In conclusion, SA alleviated the negative effect of salt stress in the M. sativa-S. meliloti symbiosis through the increased level of nodule biomass and the induction of the nodular antioxidant metabolism under salt stress. The H2O2 accumulation and the PAs inhibition induced by SA in nodules of M. sativa suggest that SA activates a hypersensitive response dependent on ethylene.

  4. Differential response of the plant Medicago truncatula to its symbiont Sinorhizobium meliloti or an exopolysaccharide-deficient mutant.

    Science.gov (United States)

    Jones, Kathryn M; Sharopova, Natalya; Lohar, Dasharath P; Zhang, Jennifer Q; VandenBosch, Kathryn A; Walker, Graham C

    2008-01-15

    Sinorhizobium meliloti forms symbiotic, nitrogen-fixing nodules on the roots of Medicago truncatula. The bacteria invade and colonize the roots through structures called infection threads. S. meliloti unable to produce the exopolysaccharide succinoglycan are unable to establish a symbiosis because they are defective in initiating the production of infection threads and in invading the plant. Here, we use microarrays representing 16,000 M. truncatula genes to compare the differential transcriptional responses of this host plant to wild-type and succinoglycan-deficient S. meliloti at the early time point of 3 days postinoculation. This report describes an early divergence in global plant gene expression responses caused by a rhizobial defect in succinoglycan production, rather than in Nod factor production. The microarray data show that M. truncatula inoculated with wild-type, succinoglycan-producing S. meliloti more strongly express genes encoding translation components, protein degradation machinery, and some nodulins than plants inoculated with succinoglycan-deficient bacteria. This finding is consistent with wild-type-inoculated plants having received a signal, distinct from the well characterized Nod factor, to alter their metabolic activity and prepare for invasion. In contrast, M. truncatula inoculated with succinoglycan-deficient S. meliloti more strongly express an unexpectedly large number of genes in two categories: plant defense responses and unknown functions. One model consistent with our results is that appropriate symbiotically active exopolysaccharides act as signals to plant hosts to initiate infection thread formation and that, in the absence of this signal, plants terminate the infection process, perhaps via a defense response.

  5. Symbiotic rhizobia bacteria trigger a change in localization and dynamics of the Medicago truncatula receptor kinase LYK3.

    Science.gov (United States)

    Haney, Cara H; Riely, Brendan K; Tricoli, David M; Cook, Doug R; Ehrhardt, David W; Long, Sharon R

    2011-07-01

    To form nitrogen-fixing symbioses, legume plants recognize a bacterial signal, Nod Factor (NF). The legume Medicago truncatula has two predicted NF receptors that direct separate downstream responses to its symbiont Sinorhizobium meliloti. NOD FACTOR PERCEPTION encodes a putative low-stringency receptor that is responsible for calcium spiking and transcriptional responses. LYSIN MOTIF RECEPTOR-LIKE KINASE3 (LYK3) encodes a putative high-stringency receptor that mediates bacterial infection. We localized green fluorescent protein (GFP)-tagged LYK3 in M. truncatula and found that it has a punctate distribution at the cell periphery consistent with a plasma membrane or membrane-tethered vesicle localization. In buffer-treated control roots, LYK3:GFP puncta are dynamic. After inoculation with compatible S. meliloti, LYK3:GFP puncta are relatively stable. We show that increased LYK3:GFP stability depends on bacterial NF and NF structure but that NF is not sufficient for the change in LYK3:GFP dynamics. In uninoculated root hairs, LYK3:GFP has little codistribution with mCherry-tagged FLOTILLIN4 (FLOT4), another punctate plasma membrane-associated protein required for infection. In inoculated root hairs, we observed an increase in FLOT4:mCherry and LYK3:GFP colocalization; both proteins localize to positionally stable puncta. We also demonstrate that the localization of tagged FLOT4 is altered in plants carrying a mutation that inactivates the kinase domain of LYK3. Our work indicates that LYK3 protein localization and dynamics are altered in response to symbiotic bacteria.

  6. Medicago truncatula improves salt tolerance when nodulated by an indole-3-acetic acid-overproducing Sinorhizobium meliloti strain.

    Science.gov (United States)

    Bianco, Carmen; Defez, Roberto

    2009-01-01

    The abiotic stress resistance of wild-type Sinorhizobium meliloti 1021 was compared with that of RD64, a derivative of the 1021 strain harbouring an additional pathway for the synthesis of indole-3-acetic acid (IAA), expressed in both free-living bacteria and bacteroids. It is shown here that the IAA-overproducing RD64 strain accumulated a higher level of trehalose as its endogenous osmolyte and showed an increased tolerance to several stress conditions (55 degrees C, 4 degrees C, UV-irradiation, 0.5 M NaCl, and pH 3). Medicago truncatula plants nodulated by RD64 (Mt-RD64) showed re-modulation of phytohormones, with a higher IAA content in nodules and roots and a decreased IAA level in shoots as compared with plants nodulated by the wild-type strain 1021 (Mt-1021). The response of nodulated M. truncatula plants to salt stress, when 0.3 M NaCl was applied, was analysed. For Mt-RD64 plants higher internal proline contents, almost unchanged hydrogen peroxide levels, and enhanced activity of antioxidant enzymes (superoxide dismutase, total peroxidase, glutathione reductase, and ascorbate peroxidase) were found compared with Mt-1021 plants. These results were positively correlated with reduced symptoms of senescence, lower expression of ethylene signalling genes, lower reduction of shoot dry weight, and better nitrogen-fixing capacity observed for these plants. Upon re-watering, after 0.3 M NaCl treatment, Mt-1021 plants almost die whereas Mt-RD64 plants showed visual signs of recovery. Finally, the shoot dry weight of Mt-RD64 plants treated with 0.15 M NaCl was not statistically different from that of Mt-1021 plants grown under non-stressed conditions.

  7. Selective recruitment of mRNAs and miRNAs to polyribosomes in response to rhizobia infection in Medicago truncatula.

    Science.gov (United States)

    Reynoso, Mauricio Alberto; Blanco, Flavio Antonio; Bailey-Serres, Julia; Crespi, Martín; Zanetti, María Eugenia

    2013-01-01

    Translation of mRNAs is a key regulatory step that contributes to the coordination and modulation of eukaryotic gene expression during development or adaptation to the environment. mRNA stability or translatability can be regulated by the action of small regulatory RNAs (sRNAs), which control diverse biological processes. Under low nitrogen conditions, leguminous plants associate with soil bacteria and develop a new organ specialized in nitrogen fixation: the nodule. To gain insight into the translational regulation of mRNAs during nodule formation, the association of mRNAs and sRNAs to polysomes was characterized in roots of the model legume Medicago truncatula during the symbiotic interaction with Sinorhizobium meliloti. Quantitative comparison of steady-state and polysomal mRNAs for 15 genes involved in nodulation identified a group of transcripts with slight or no change in total cellular abundance that were significantly upregulated at the level of association with polysomes in response to rhizobia. This group included mRNAs encoding receptors like kinases required either for nodule organogenesis, bacterial infection or both, and transcripts encoding GRAS and NF-Y transcription factors (TFs). Quantitative analysis of sRNAs in total and polysomal RNA samples revealed that mature microRNAs (miRNAs) were associated with the translational machinery, notably, miR169 and miR172, which target the NF-YA/HAP2 and AP2 TFs, respectively. Upon inoculation, levels of miR169 pronouncedly decreased in polysomal complexes, concomitant with the increased accumulation of the NF-YA/HAP2 protein. These results indicate that both mRNAs and miRNAs are subject to differential recruitment to polysomes, and expose the importance of selective mRNA translation during root nodule symbiosis.

  8. Both plant and bacterial nitrate reductases contribute to nitric oxide production in Medicago truncatula nitrogen-fixing nodules.

    Science.gov (United States)

    Horchani, Faouzi; Prévot, Marianne; Boscari, Alexandre; Evangelisti, Edouard; Meilhoc, Eliane; Bruand, Claude; Raymond, Philippe; Boncompagni, Eric; Aschi-Smiti, Samira; Puppo, Alain; Brouquisse, Renaud

    2011-02-01

    Nitric oxide (NO) is a signaling and defense molecule of major importance in living organisms. In the model legume Medicago truncatula, NO production has been detected in the nitrogen fixation zone of the nodule, but the systems responsible for its synthesis are yet unknown and its role in symbiosis is far from being elucidated. In this work, using pharmacological and genetic approaches, we explored the enzymatic source of NO production in M. truncatula-Sinorhizobium meliloti nodules under normoxic and hypoxic conditions. When transferred from normoxia to hypoxia, nodule NO production was rapidly increased, indicating that NO production capacity is present in functioning nodules and may be promptly up-regulated in response to decreased oxygen availability. Contrary to roots and leaves, nodule NO production was stimulated by nitrate and nitrite and inhibited by tungstate, a nitrate reductase inhibitor. Nodules obtained with either plant nitrate reductase RNA interference double knockdown (MtNR1/2) or bacterial nitrate reductase-deficient (napA) and nitrite reductase-deficient (nirK) mutants, or both, exhibited reduced nitrate or nitrite reductase activities and NO production levels. Moreover, NO production in nodules was found to be inhibited by electron transfer chain inhibitors, and nodule energy state (ATP-ADP ratio) was significantly reduced when nodules were incubated in the presence of tungstate. Our data indicate that both plant and bacterial nitrate reductase and electron transfer chains are involved in NO synthesis. We propose the existence of a nitrate-NO respiration process in nodules that could play a role in the maintenance of the energy status required for nitrogen fixation under oxygen-limiting conditions.

  9. Ectopic expression of GsPPCK3 and SCMRP in Medicago sativa enhances plant alkaline stress tolerance and methionine content.

    Directory of Open Access Journals (Sweden)

    Mingzhe Sun

    Full Text Available So far, it has been suggested that phosphoenolpyruvate carboxylases (PEPCs and PEPC kinases (PPCKs fulfill several important non-photosynthetic functions. However, the biological functions of soybean PPCKs, especially in alkali stress response, are not yet well known. In previous studies, we constructed a Glycine soja transcriptional profile, and identified three PPCK genes (GsPPCK1, GsPPCK2 and GsPPCK3 as potential alkali stress responsive genes. In this study, we confirmed the induced expression of GsPPCK3 under alkali stress and investigated its tissue expression specificity by using quantitative real-time PCR analysis. Then we ectopically expressed GsPPCK3 in Medicago sativa and found that GsPPCK3 overexpression improved plant alkali tolerance, as evidenced by lower levels of relative ion leakage and MDA content and higher levels of chlorophyll content and root activity. In this respect, we further co-transformed the GsPPCK3 and SCMRP genes into alfalfa, and demonstrated the increased alkali tolerance of GsPPCK3-SCMRP transgenic lines. Further investigation revealed that GsPPCK3-SCMRP co-overexpression promoted the PEPC activity, net photosynthetic rate and citric acid content of transgenic alfalfa under alkali stress. Moreover, we also observed the up-regulated expression of PEPC, CS (citrate synthase, H(+-ATPase and NADP-ME genes in GsPPCK3-SCMRP transgenic alfalfa under alkali stress. As expected, we demonstrated that GsPPCK3-SCMRP transgenic lines displayed higher methionine content than wild type alfalfa. Taken together, results presented in this study supported the positive role of GsPPCK3 in plant response to alkali stress, and provided an effective way to simultaneously improve plant alkaline tolerance and methionine content, at least in legume crops.

  10. Interaction between Medicago truncatula and Pseudomonas fluorescens: evaluation of costs and benefits across an elevated atmospheric CO(2.

    Directory of Open Access Journals (Sweden)

    Clémentine Lepinay

    Full Text Available Soil microorganisms play a key role in both plants nutrition and health. Their relation with plant varies from mutualism to parasitism, according to the balance of costs and benefits for the two partners of the interaction. These interactions involved the liberation of plant organic compounds via rhizodeposition. Modification of atmospheric CO(2 concentration may affect rhizodeposition and as a consequence trophic interactions that bind plants and microorganisms. Positive effect of elevated CO(2 on plants are rather well known but consequences for micoorganisms and their interactions with plants are still poorly understood. A gnotobiotic system has been developed to study the interaction between Medicago truncatula Jemalong J5 and the mutualistic bacteria Pseudomonas fluorescens strain C7R12 under two atmospheric CO(2 concentrations: ambient (365 ppm versus enriched (750 ppm. Costs and benefits for each partner have been determined over time by measuring plant development and growth, the C and N contents of the various plant parts and the density of the bacteria in rhizosphere compartments. Following the increase in CO(2, there was a beneficial effect of P. fluorescens C7R12 on development, vegetative growth, and C/N content of M. truncatula. Concerning plant reproduction, an early seed production was noticed in presence of the bacterial strain combined with increased atmospheric CO(2 conditions. Paradoxically, this transient increase in seed production was correlated with a decrease in bacterial density in the rhizosphere soil, revealing a cost of increased CO(2 for the bacterial strain. This shift of costs-benefits ratio disappeared later during the plant growth. In conclusion, the increase in CO(2 concentration modifies transiently the cost-benefit balance in favor of the plant. These results may be explained either by a competition between the two partners or a change in bacterial physiology. The ecosystem functioning depends on the

  11. Interaction between Medicago truncatula and Pseudomonas fluorescens: evaluation of costs and benefits across an elevated atmospheric CO(2).

    Science.gov (United States)

    Lepinay, Clémentine; Rigaud, Thierry; Salon, Christophe; Lemanceau, Philippe; Mougel, Christophe

    2012-01-01

    Soil microorganisms play a key role in both plants nutrition and health. Their relation with plant varies from mutualism to parasitism, according to the balance of costs and benefits for the two partners of the interaction. These interactions involved the liberation of plant organic compounds via rhizodeposition. Modification of atmospheric CO(2) concentration may affect rhizodeposition and as a consequence trophic interactions that bind plants and microorganisms. Positive effect of elevated CO(2) on plants are rather well known but consequences for micoorganisms and their interactions with plants are still poorly understood. A gnotobiotic system has been developed to study the interaction between Medicago truncatula Jemalong J5 and the mutualistic bacteria Pseudomonas fluorescens strain C7R12 under two atmospheric CO(2) concentrations: ambient (365 ppm) versus enriched (750 ppm). Costs and benefits for each partner have been determined over time by measuring plant development and growth, the C and N contents of the various plant parts and the density of the bacteria in rhizosphere compartments. Following the increase in CO(2), there was a beneficial effect of P. fluorescens C7R12 on development, vegetative growth, and C/N content of M. truncatula. Concerning plant reproduction, an early seed production was noticed in presence of the bacterial strain combined with increased atmospheric CO(2) conditions. Paradoxically, this transient increase in seed production was correlated with a decrease in bacterial density in the rhizosphere soil, revealing a cost of increased CO(2) for the bacterial strain. This shift of costs-benefits ratio disappeared later during the plant growth. In conclusion, the increase in CO(2) concentration modifies transiently the cost-benefit balance in favor of the plant. These results may be explained either by a competition between the two partners or a change in bacterial physiology. The ecosystem functioning depends on the stability of many

  12. Possible role of glutamine synthetase of the prokaryotic type (GSI-like) in nitrogen signaling in Medicago truncatula.

    Science.gov (United States)

    Silva, Liliana S; Seabra, Ana R; Leitão, José N; Carvalho, Helena G

    2015-11-01

    Genes containing domains related to glutamine synthetase of the prokaryotic type (GSI-like) are widespread in higher plants, but their function is currently unknown. To gain insights into the possible role of GSI-like proteins, we characterized the GSI-like gene family of Medicago truncatula and investigated the functionality of the encoded proteins. M. truncatula contains two-expressed GSI-like genes, MtGSIa and MtGSIb, encoding polypeptides of 454 and 453 amino acids, respectively. Heterologous complementation assays of a bacterial glnA mutant indicate that the proteins are not catalytically functional for glutamine synthesis. Gene expression was investigated by qRT-PCR and western blot analysis in different organs of the plant and under different nitrogen (N) regimes, revealing that both genes are preferentially expressed in roots and root nodules, and that their expression is influenced by the N-status of the plant. Analysis of transgenic plants expressing MtGSI-like-promoter-gusA fusion, indicate that the two genes are strongly expressed in the root pericycle, and interestingly, the expression is enhanced at the sites of nodule emergence being particularly strong in specific cells located in front of the protoxylem poles. Taken together, the results presented here support a role of GSI-like proteins in N sensing and/or signaling, probably operating at the interface between perception of the N-status and the developmental processes underlying both root nodule and lateral root formation. This study indicates that GSI-like genes may represent a novel class of molecular players of the N-mediated signaling events.

  13. Functional assessment of the Medicago truncatula NIP/LATD protein demonstrates that it is a high-affinity nitrate transporter.

    Science.gov (United States)

    Bagchi, Rammyani; Salehin, Mohammad; Adeyemo, O Sarah; Salazar, Carolina; Shulaev, Vladimir; Sherrier, D Janine; Dickstein, Rebecca

    2012-10-01

    The Medicago truncatula NIP/LATD (for Numerous Infections and Polyphenolics/Lateral root-organ Defective) gene encodes a protein found in a clade of nitrate transporters within the large NRT1(PTR) family that also encodes transporters of dipeptides and tripeptides, dicarboxylates, auxin, and abscisic acid. Of the NRT1(PTR) members known to transport nitrate, most are low-affinity transporters. Here, we show that M. truncatula nip/latd mutants are more defective in their lateral root responses to nitrate provided at low (250 μm) concentrations than at higher (5 mm) concentrations; however, nitrate uptake experiments showed no discernible differences in uptake in the mutants. Heterologous expression experiments showed that MtNIP/LATD encodes a nitrate transporter: expression in Xenopus laevis oocytes conferred upon the oocytes the ability to take up nitrate from the medium with high affinity, and expression of MtNIP/LATD in an Arabidopsis chl1(nrt1.1) mutant rescued the chlorate susceptibility phenotype. X. laevis oocytes expressing mutant Mtnip-1 and Mtlatd were unable to take up nitrate from the medium, but oocytes expressing the less severe Mtnip-3 allele were proficient in nitrate transport. M. truncatula nip/latd mutants have pleiotropic defects in nodulation and root architecture. Expression of the Arabidopsis NRT1.1 gene in mutant Mtnip-1 roots partially rescued Mtnip-1 for root architecture defects but not for nodulation defects. This suggests that the spectrum of activities inherent in AtNRT1.1 is different from that possessed by MtNIP/LATD, but it could also reflect stability differences of each protein in M. truncatula. Collectively, the data show that MtNIP/LATD is a high-affinity nitrate transporter and suggest that it could have another function.

  14. nip, a symbiotic Medicago truncatula mutant that forms root nodules with aberrant infection threads and plant defense-like response.

    Science.gov (United States)

    Veereshlingam, Harita; Haynes, Janine G; Penmetsa, R Varma; Cook, Douglas R; Sherrier, D Janine; Dickstein, Rebecca

    2004-11-01

    To investigate the legume-Rhizobium symbiosis, we isolated and studied a novel symbiotic mutant of the model legume Medicago truncatula, designated nip (numerous infections and polyphenolics). When grown on nitrogen-free media in the presence of the compatible bacterium Sinorhizobium meliloti, the nip mutant showed nitrogen deficiency symptoms. The mutant failed to form pink nitrogen-fixing nodules that occur in the wild-type symbiosis, but instead developed small bump-like nodules on its roots that were blocked at an early stage of development. Examination of the nip nodules by light microscopy after staining with X-Gal for S. meliloti expressing a constitutive GUS gene, by confocal microscopy following staining with SYTO-13, and by electron microscopy revealed that nip initiated symbiotic interactions and formed nodule primordia and infection threads. The infection threads in nip proliferated abnormally and very rarely deposited rhizobia into plant host cells; rhizobia failed to differentiate further in these cases. nip nodules contained autofluorescent cells and accumulated a brown pigment. Histochemical staining of nip nodules revealed this pigment to be polyphenolic accumulation. RNA blot analyses demonstrated that nip nodules expressed only a subset of genes associated with nodule organogenesis, as well as elevated expression of a host defense-associated phenylalanine ammonia lyase gene. nip plants were observed to have abnormal lateral roots. nip plant root growth and nodulation responded normally to ethylene inhibitors and precursors. Allelism tests showed that nip complements 14 other M. truncatula nodulation mutants but not latd, a mutant with a more severe nodulation phenotype as well as primary and lateral root defects. Thus, the nip mutant defines a new locus, NIP, required for appropriate infection thread development during invasion of the nascent nodule by rhizobia, normal lateral root elongation, and normal regulation of host defense-like responses

  15. Peroxidases from root exudates of Medicago sativa and Sorghum bicolor: Catalytic properties and involvement in PAH degradation.

    Science.gov (United States)

    Dubrovskaya, Ekaterina; Pozdnyakova, Natalia; Golubev, Sergey; Muratova, Anna; Grinev, Vyacheslav; Bondarenkova, Anastasiya; Turkovskaya, Olga

    2017-02-01

    Peroxidases from root exudates of sorghum (Sorghum bicolor L. Moench) and alfalfa (Medicago sativa L.) were purified and characterized, and their ability to oxidize native PAHs and PAH-derivatives was evaluated. The obtained data confirm that peroxidases are involved in the rhizosphere degradation of PAHs. Nondenaturing PAGE showed that the peroxidases of both plants were represented by a range of isoforms/isoenzymes (five to eight). Minor forms were lost during further purification, and as a result, the major anionic form from alfalfa root exudates and the major cationic form from those of sorghum were obtained. Both electrophoretically homogeneous peroxidases were monomeric proteins with a molecular weight of about 46-48 kDa. The pH optima and the main catalytic constants for the test substrates were determined. On the basis of their molecular and catalytic properties, the obtained enzymes were found to be typical plant peroxidases. Derivatives of PAHs and potential products of their microbial degradation (9-phenanthrol and 9,10-phenanthrenequinone), unlike the parent PAH (phenanthrene), inhibited the catalytic activity of the peroxidases, possibly indicating greater availability of the enzymes' active centers to these substances. Peroxidase-catalyzed decreases in the concentrations of a number of PAHs and their derivatives were observed. Sorghum peroxidase oxidized anthracene and phenanthrene, while alfalfa peroxidase oxidized only phenanthrene. 1-Hydroxy-2-naphthoic acid was best oxidized by peroxidase of alfalfa. However, quinone derivatives of PAHs were unavailable to sorghum peroxidase, but were oxidized by alfalfa peroxidase. These results indicate that the major peroxidases from root exudates of alfalfa and sorghum can have a role in the rhizosphere degradation of PAHs.

  16. Genome-wide analysis of the AP2/ERF superfamily genes and their responses to abiotic stress in Medicago truncatula

    Directory of Open Access Journals (Sweden)

    Yongjun eShu

    2016-01-01

    Full Text Available The AP2/ERF superfamily is a large, plant-specific transcription factor family that is involved in many important processes, including plant growth, development and stress responses. Using Medicago truncatula genome information, we identified and characterized 123 putative AP2/ERF genes, which were named as MtERF1–123. These genes were classified into four families based on phylogenetic analysis, which is consistent with the results of other plant species. MtERF genes are distributed throughout all chromosomes but are clustered on various chromosomes due to genomic tandem and segmental duplication. Using transcriptome, high-throughput sequencing data and qRT-PCR analysis, we assessed the expression patterns of the MtERF genes in tissues during development and under abiotic stresses. In total, 87 MtERF genes were expressed in plant tissues, most of which were expressed in specific tissues during development or under specific abiotic stress treatments. These results support the notion that MtERF genes are involved in developmental regulation and environmental responses in M. truncatula. Furthermore, a cluster of DREB subfamily members on chromosome 6 was induced by both cold and freezing stress, representing a positive gene regulatory response under low temperature stress, which suggests that these genes might contribute to freezing tolerance to M. truncatula. In summary, our genome-wide characterization, evolutionary analysis and expression pattern analysis of MtERF genes in M. truncatula provides valuable information for characterizing the molecular functions of these genes and utilizing them to improve stress tolerance in plants.

  17. Genome-Wide Analysis of the AP2/ERF Superfamily Genes and their Responses to Abiotic Stress in Medicago truncatula

    Science.gov (United States)

    Shu, Yongjun; Liu, Ying; Zhang, Jun; Song, Lili; Guo, Changhong

    2016-01-01

    The AP2/ERF superfamily is a large, plant-specific transcription factor family that is involved in many important processes, including plant growth, development, and stress responses. Using Medicago truncatula genome information, we identified and characterized 123 putative AP2/ERF genes, which were named as MtERF1–123. These genes were classified into four families based on phylogenetic analysis, which is consistent with the results of other plant species. MtERF genes are distributed throughout all chromosomes but are clustered on various chromosomes due to genomic tandem and segmental duplication. Using transcriptome, high-throughput sequencing data, and qRT-PCR analysis, we assessed the expression patterns of the MtERF genes in tissues during development and under abiotic stresses. In total, 87 MtERF genes were expressed in plant tissues, most of which were expressed in specific tissues during development or under specific abiotic stress treatments. These results support the notion that MtERF genes are involved in developmental regulation and environmental responses in M. truncatula. Furthermore, a cluster of DREB subfamily members on chromosome 6 was induced by both cold and freezing stress, representing a positive gene regulatory response under low temperature stress, which suggests that these genes might contribute to freezing tolerance to M. truncatula. In summary, our genome-wide characterization, evolutionary analysis, and expression pattern analysis of MtERF genes in M. truncatula provides valuable information for characterizing the molecular functions of these genes and utilizing them to improve stress tolerance in plants. PMID:26834762

  18. Insight into the role of anthocyanin biosynthesis-related genes in Medicago truncatula mutants impaired in pigmentation in leaves.

    Science.gov (United States)

    Carletti, Giorgia; Lucini, Luigi; Busconi, Matteo; Marocco, Adriano; Bernardi, Jamila

    2013-09-01

    Flavonoids are the most common antioxidant compounds produced in plants. In this study, two wild types and two independent mutants of Medicago truncatula with altered anthocyanin content in leaves were characterized at the phenotype, metabolite profile, gene structure and transcript levels. Flavonoid profiles showed conserved levels of dihydroflavonols, leucoanthocyanidins and flavonols, while anthocyanidin, anthocyanin and isoflavone levels were lower in the mutants (up to 90% less) compared with the wild types. Genes encoding key enzymes of the anthocyanin pathway and transcriptional factors were analyzed by RT-PCR. Genes involved in the later steps of the anthocyanin pathway (dihydrokaempferol reductase 2, UDP-glucose:anthocyanin 3-O-glucosyltransferase and glutathione S-transferase) were found under-expressed in both mutants. Dihydrokaempferol reductase 1 was downregulated two-fold in the anthocyanin-less mutant while the UDP-glucose:anthocyanin 5-O-glucosyltransferase was strongly repressed only in the mutant with low pigmentation, suggesting a different regulation in the two genotypes. The common feature was that the first enzymes of the flavonoid biosynthesis pathway were not altered in rate of expression. A very high reduction in transcript accumulation was also found for two homologous R2R3 MYB genes, namely MtMYBA and AN2, suggesting that these genes have a role in anthocyanin accumulation in leaves. More evidence was found on analyzing their nucleotide sequence: several SNPs, insertions and deletions in the coding and non-coding regions of both MYB genes were found between mutants and wild types that could influence anthocyanin biosynthesis. Moreover, a subfamily of eight MYB genes with a high homology to MtMYBA was discovered in tandem on chromosome 5 of M. truncatula.

  19. Regulation of anthocyanin and proanthocyanidin biosynthesis by Medicago truncatula bHLH transcription factor MtTT8.

    Science.gov (United States)

    Li, Penghui; Chen, Beibei; Zhang, Gaoyang; Chen, Longxiang; Dong, Qiang; Wen, Jiangqi; Mysore, Kirankumar S; Zhao, Jian

    2016-05-01

    The MYB- basic helix-loop-helix (bHLH)-WD40 complexes regulating anthocyanin and proanthocyanidin (PA) biosynthesis in plants are not fully understood. Here Medicago truncatula bHLH MtTT8 was characterized as a central component of these ternary complexes that control anthocyanin and PA biosynthesis. Mttt8 mutant seeds have a transparent testa phenotype with reduced PAs and anthocyanins. MtTT8 restores PA and anthocyanin productions in Arabidopsis tt8 mutant. Ectopic expression of MtTT8 restores anthocyanins and PAs in mttt8 plant and hairy roots and further enhances both productions in wild-type hairy roots. Transcriptomic analyses and metabolite profiling of mttt8 mutant seeds and M. truncatula hairy roots (mttt8 mutant, mttt8 mutant complemented with MtTT8, or MtTT8 overexpression lines) indicate that MtTT8 regulates a subset of genes involved in PA and anthocyanin biosynthesis. MtTT8 is genetically regulated by MtLAP1, MtPAR and MtWD40-1. Combinations of MtPAR, MtLAP1, MtTT8 and MtWD40-1 activate MtTT8 promoter in yeast assay. MtTT8 interacts with these transcription factors to form regulatory complexes. MtTT8, MtWD40-1 and an MYB factor, MtPAR or MtLAP1, interacted and activated promoters of anthocyanidin reductase and anthocyanidin synthase to regulate PA and anthocyanin biosynthesis, respectively. Our results provide new insights into the complex regulation of PA and anthocyanin biosynthesis in M. truncatula.

  20. [MEDICAGO SATIVA L: IMPROVEMENT AND NEW APPROACHES OF ITS NUTRITIONAL AND FUNCTIONAL VALUE BY BACTERIAL CO-INOCULATION].

    Science.gov (United States)

    Martínez, Rosario; Nebot, Elena; Porres, Jesús María; Kapravelou, Garyfallia; Del Moral, Ana; Talbi, Chouhra; Bedmar, Eulogio Jose; López-Jurado, María

    2015-12-01

    Objetivo: estudiar el efecto de la inoculación con Ensifer meliloti y Halomonas maura sobre el crecimiento y el valor nutricional y funcional de la leguminosa Medicago sativa L., cultivada bajo condiciones de salinidad. Método: las plantas de M. sativa se cultivaron con una solución de mezcla de sales CaSO4, MgCl, NaCl and Na- HCO3 y se coinocularon con su rizobio específico y la bacteria H. maura. Se determinaron los parámetros fisiológicos de las plantas, así como el contenido en nitrógeno y minerales, y se llevó a cabo un proceso de digestibilidad in vitro. Resultados: la salinidad ejerció un efecto negativo sobre las plantas; sin embargo, la coinoculación de las mismas incrementó su productividad, el contenido en nitrógeno, minerales totales, Ca y Mg. Además, los parámetros fisiológicos de potencial hídrico y concentración de leghemoglobina se incrementaron. Tanto la salinidad como la coinoculación de las plantas aumentaron la capacidad antioxidante de la leguminosa en los dializados y retenidos obtenidos tras someter a la planta a un proceso de digestibilidad in vitro. Conclusión: la coinoculación con E. meliloti y H. maura podría mejorar el cultivo de la alfalfa bajo condiciones específicas de salinidad, aumentando su composición nutricional y funcional, pudiendo considerarse en la formulación de suplementos nutricionales para el consumo humano.