Effect of vanadium and tungsten on nitrogen fixation and the growth of Medicago sativa

Energy Technology Data Exchange (ETDEWEB)

Jha, K K

1969-01-01

In sand culture, it was found that vanadium had no stimulatory effect on nitrogen content or the growth of Medicago sativa inoculated with an effective strain of Rhizobium meliloti or supplied with ammonium nitrate. At the level of 500 ppm it reduced the plant growth, the inhibitory effect being particularly severe on the root. On the other hand tungsten increased nitrogen fixation and the dry matter yield of the inoculated plants. The results are suggestive of a direct role of tungsten in symbiotic nitrogen fixation. 4 references, 2 tables.

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.

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

Science.gov (United States)

Bingham, Edwin; Armour, David; Irwin, John

2013-01-01

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. PMID:27137379

Transgene silencing of sucrose synthase in alfalfa (Medicago sativa L.) stem vascular tissue suggests a role for invertase in cell wall cellulose synthesis

Science.gov (United States)

Alfalfa (Medicago sativa L.) plants were transformed with two constructs: (1) a truncated phosphoenolpyruvate carboxylase promoter isolated from alfalfa nodules (PEPC-4) fused to GUS; and (2) PEPC-4 fused with sucrose synthase (SUS) isolated from alfalfa nodules. Histochemical staining for GUS in st...

Differential response to water deficit stress in alfalfa ( Medicago ...

African Journals Online (AJOL)

The present study was fixed as objective to compare the response to water deficit (33% of field capacity, FC) stress of eight cultivars of Medicago sativa, originating from the Mediterranean basin. Comparison was performed on some key parameters such as growth, relative water content, leaf water potential, MDA tissue ...

Nitrogen accumulation in lucerne (Medicago sativa L. under water deficit stress

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Vasileva Viliana

2013-01-01

Full Text Available In order to study nitrogen accumulation in aboveground and root dry mass in lucerne (Medicago sativa L. under water deficit stress, a pot experiment was carried out at the Institute of Forage Crops, Pleven, Bulgaria. The plants were grown under optimum water supply (75-80% FC and 10-days water deficit stress was simulated at the stage of budding by interrupting the irrigation until soil moisture was reduced to 37-40% FC. Mineral nitrogen fertilization (ammonium nitrate at the doses of 40, 80, 120 and 160 mg N kg-1 soil was applied. It was found that nitrogen accumulation in dry aboveground mass was reduced to 18.0%, and in dry root mass to 26.5% under water deficit stress. Mineral nitrogen fertilization contributed to easily overcome the stress conditions of water deficit stress in lucerne.

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

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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.

Stress responses in alfalfa (Medicago sativa L.)

International Nuclear Information System (INIS)

Kessmann, H.; Edwards, R.; Dixon, R.A.; Geno, P.W.

1990-01-01

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 [ 14 C]phenylalanine indicated that afrormosin conjugates were the major de novo synthesized isoflavonoid products in unelicited cells. During elicitation, [ 14 C]phenylalanine was incorporated predominantly into medicarpin, although a significant proportion of the newly synthesized medicarpin was also conjugated. Treatment of 14 C-labeled, elicited cells with L-α-aminooxy-β-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

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.)

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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...

[The effect of Medicago spp. on growth of Trichophyton mentagrophytes in microculture].

Science.gov (United States)

Spiewak, R; Szostak, W; Jurzysta, M; Biały, Z; Maleszka, R; Rzepecka, B; Mazurek, M

2001-01-01

The study aimed at assessing effect of dried root and aerial parts of Medicago spp. on growth of Trichophryton mentagrophytes. Fungus strains were inoculated onto microcultures with Sabouraud agar supplemented each with 1 g of dried and pulverised roots or aerial parts of 3 species: Medicago arabica, M. sativa, and M. murex. The strongest inhibitory effect on T. mentagrophytes growth was that of aerial parts of M. arabica (median diameter 6 mm compared to 13 mm of control), followed by root of M. arabica (10 mm) and root of M. murex (10.5 mm)--in all cases p < 0.001. Slight inhibitory effect was also found in the case of aerial parts of M. murex (median diameter 12 mm, p = 0.03). In contrast, M. sativa has shown stimulating effect on growth of T. mentagrophytes (15 mm for root and 16.5 mm for aerial part, p<0.001).

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

International Nuclear Information System (INIS)

Kong, W.D.; Zhu, Y.G.; Liang, Y.C.; Zhang, J.; Smith, F.A.; Yang, M.

2007-01-01

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 max of 2.25 μmol g -1 fresh weight h -1 , and K 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 + . OTC uptake, however, was significantly inhibited by Hg 2+ , suggesting that the inhibition of influx was due to general cellular stress rather than the specific action of Hg 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

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

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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.

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.

WATER DEFICIT EFFECT ON YIELD AND FORAGE QUALITY OF MEDICAGO SATIVA POPULATIONS UNDER FIELD CONDITIONS IN MARRAKESH AREA (MOROCCO)

OpenAIRE

Mohamed FARISSI; Cherki GHOULAM; Abdelaziz BOUIZGAREN

2014-01-01

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...

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.

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. Copyright © 2014 Asociación Colombiana de Psiquiatría. Publicado por Elsevier España. All rights reserved.

A PROPOSITO DE UN ENSAYO CON ABONOS (cal y harina de huesos EN ALFALFAl (Medicago sativa

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Isidoro Mogilner

1960-01-01

Full Text Available En este trabajo, los autores estudian el efecto que sobre el rendimiento de la alfalfa (Medicago sativa produce la incorporación de diferentes dosis de cal y harina de huesos, en un suelo pobre de P y Ca; de una textura pesada con alto contenido de arcilla en todos los horizontes, de un pH ácido (5.1 a 6.2 y que es característico de la zona donde fué hecha la experiencia.Se han obtenido resultados referentes a la influencia de la inoculación de la semilla con Rhizobium y el agregado de cal y harina de huesos sobre los rendimientos.

Fotossíntese em alfafa (Medicago sativa L.) sob supressão e ressuprimento de fosfato

OpenAIRE

Gomes,Fernando Teixeira; Pereira,Gilmara Duarte; Borges,Arnaldo Chaer; Mosquim,Paulo Roberto

2003-01-01

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 amostrada...

Effects of the weed density on grass yield of Alfalfa ( Medicago ...

African Journals Online (AJOL)

This study, in which the effects of different row spacing applications on weed density and on grass yield of Medicago sativa L. were investigated, was carried out in Van-Turkey from 2006 - 2008. Randomized blocks design was adopted with three replications. Row spacing applications of 20, 30, 40, 50, 60 and 70 cm were ...

Production of aerial biomass and equivalent land use in alfalfa (Medicago sativa L.) intercropping

International Nuclear Information System (INIS)

Pereyra, T. W.; Pagliaricci, H. R.; Ohanian, A. E.; Bonvillani, M. J.

2013-01-01

Productivity increase has traditionally been associated to yield increase through breeding and crop management practices. Nevertheless, if production is considered per area and time unit, the intercropping system may be another way to improve cost-effectiveness. The objective of the experiment was to determine the produced biomass and the equivalent land use in alfalfa (Medicago sativa L.) monocrop and intercrops with sorghum Sudan (Sorghum sudanense L.) and oat (Avena sativa L.). The aerial biomass of all the treatments (expressed per surface unit) and the equivalent land use were determined. The design was completely randomized, arranged in blocks with two repetitions. The results were subject to an ANAVA and the means were compared through Duncan's test, by means of the statistical pack INFOSTAT. The alfalfa-sorghum intercrop triplicated the alfalfa production with regards to the monocrop, while alfalfa-oat did not exceed the production of pure alfalfa in the winter months. The alfalfa-sorghum intercrop was 57 % more efficient in land use than the respective monocrops, while alfalfa-oat did not surpass the unit. (author)

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); 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.

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.

Monolignol biosynthesis in microsomal preparations from lignifying stems of alfalfa (Medicago sativa L.).

Science.gov (United States)

Guo, Dianjing; Chen, Fang; Dixon, Richard A

2002-11-01

Microsomal preparations from lignifying stems of alfalfa (Medicago sativa L.) contained coniferaldehyde 5-hydroxylase activity and immunodetectable caffeic acid 3-O-methyltransferase (COMT), and catalyzed the S-adenosyl L-methionine (SAM) dependent methylation of caffeic acid, caffeyl aldehyde and caffeyl alcohol. When supplied with NADPH and SAM, the microsomes converted caffeyl aldehyde to coniferaldehyde, 5-hydroxyconiferaldehyde, and traces of sinapaldehyde. Coniferaldehyde was a better precursor of sinapaldehyde than was 5-hydroxyconiferaldehyde. The alfalfa microsomes could not metabolize 4-coumaric acid, 4-coumaraldehyde, 4-coumaroyl CoA, or ferulic acid. No metabolism of monolignol precursors was observed in microsomal preparations from transgenic alfalfa down-regulated in COMT expression. In most microsomal preparations, the level of the metabolic conversions was independent of added recombinant COMT. Taken together, the data provide only limited support for the concept of metabolic channeling in the biosynthesis of S monolignols via coniferaldehyde.

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.

The Medicago truncatula gene expression atlas web server

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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

Exploring the plant-associated bacterial communities in Medicago sativa L

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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

Phytotoxicity of three plant-based biodiesels, unmodified castor oil, and Diesel fuel to alfalfa (Medicago sativa L.), lettuce (Lactuca sativa L.), radish (Raphanus sativus), and wheatgrass (Triticum aestivum).

Science.gov (United States)

Bamgbose, Ifeoluwa; Anderson, Todd A

2015-12-01

The wide use of plant-based oils and their derivatives, in particular biodiesel, have increased extensively over the past decade to help alleviate demand for petroleum products and improve the greenhouse gas emissions profile of the transportation sector. Biodiesel is regarded as a clean burning alternative fuel produced from livestock feeds and various vegetable oils. Although in theory these animal and/or plant derived fuels should have less environmental impact in soil based on their simplified composition relative to Diesel, they pose an environmental risk like Diesel at high concentrations when disposed. The aim of the present study was to ascertain the phytotoxicity of three different plant-derived biodiesels relative to conventional Diesel. For phytotoxicological analysis, we used seeds of four crop plants, Medicago sativa, Lactuca sativa, Raphanus sativus, and Triticum aestivum to analyze the germination of seeds in contaminated soil samples. The toxicological experiment was conducted with two different soil textures: sandy loam soil and silt loam soil. The studied plant-based biodiesels were safflower methyl-ester, castor methyl ester, and castor ethyl-ester. Biodiesel toxicity was more evident at high concentrations, affecting the germination and survival of small-seeded plants to a greater extent. Tolerance of plants to the biodiesels varied between plant species and soil textures. With the exception of R. sativus, all plant species were affected and exhibited some sensitivity to the fuels, such as delayed seedling emergence and slow germination (average=10 days) at high soil concentrations (0.85% for Diesel and 1.76% for the biodiesels). Tolerance of plants to soil contamination had a species-specific nature, and on average, decreased in the following order: Raphanus sativus (0-20%)>Triticum aestivum (10-40%) ≥ Medicago sativa> Lactuca sativa (80-100%). Thus, we conclude that there is some phytotoxicity associated with plant-based biodiesels. Further

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

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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.

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

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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.

The effect of Medicago arabica, M. hybrida and M. sativa saponins on the growth and development of Fusarium oxysporum Schlecht f. sp. tulipae apt.

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Anna Jarecka

2012-12-01

Full Text Available In the present work it was shown that total saponins originated from M. hybrida and M. sativa substantially limited mycelium growth of F. oxysporum f. sp. tulipae and symptoms of fusariosis on tulip bulbs. Out of 15 individual tested saponins originated from M. arabica, M. hybrida and M. sativa, four compounds: 3-O-[β-D-glucopyranosyl (1→2α-L-arabinopyranosyl] hederagenin, hederagenin 3-O-β-D-glucopyranoside, medicagenic acid, medicagenic acid 3-O-β-D-glucopyranoside had the strongest inhibitory effect on mycelium growth of Fusarium oxysporum f. sp. tulipae on PDA medium. The total saponins from M. arabica, M. hybrida and M. sativa inhibited the number of colony forming units of Fusarium oxysporum f. sp. tulipae in artificially infested substrate. The use of saponins originated from Medicago as a fungicide is suggested.

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

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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.

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.

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.

Fotossíntese em alfafa (Medicago sativa L. sob supressão e ressuprimento de fosfato Photosynthesis in alfalfa (Medicago sativa L. under phosphate suppression and ressuply

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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

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

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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.

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

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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.

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

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

2017-10-01

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.

Arbuscular mycorrhizal fungi alleviate arsenic toxicity to Medicago sativa by influencing arsenic speciation and partitioning.

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Li, Jinglong; Sun, Yuqing; Jiang, Xuelian; Chen, Baodong; Zhang, Xin

2018-08-15

In a pot experiment, Medicago sativa inoculated with/without arbuscular mycorrhizal (AM) fungus Rhizophagus irregularis were grown in four levels (0, 10, 25, and 75 mg/kg) of arsenic (As)-polluted soil to investigate the influences of AM symbiosis on plant As tolerance. The results showed that mycorrhizal inoculation significantly increased plant biomass, while As addition decreased mycorrhizal colonization and hyphal length density. Mycorrhizal inoculation dramatically improved plant phosphorus (P) nutrition, restricted As uptake and retained more As in roots by upregulating the expression of the AM-induced P transporter gene MsPT4 and the metallothionein gene MsMT2. High soil As content downregulated MsPT4 expression. Dimethylarsenic acid (DMA) was detected only in the shoots of mycorrhizal plants, indicating that AM fungi likely play an essential role in As detoxification by biological methylation. The present investigation allowed deeper insights into the As detoxification mechanisms of AM associations and demonstrated the important role of AM fungi in plant resistance under As-contaminated conditions. Copyright © 2018 Elsevier Inc. All rights reserved.

Effects of Shepherd’s Purse (Capsella bursa pastoris (L. Medic. on the Chemical Composition of Lucerne (Medicago sativa L.

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Tsvetanka Dimitrova

2008-01-01

Full Text Available A study was conducted in a pure stand of lucerne (variety Viktoria under natural weed infestation with shepherd’s purse (Capsella bursa pastoris (L. Medic. on a slightly leached chernozem soil under nonirrigated conditions in the experimental field of the Institute ofForage Crops – Pleven during the 2006-2007 period. The effect of shepherd’s purse Capsella bursa pastoris (L. Medic. on the chemical composition of lucerne Medicago sativa (L. was analyzed.Statistically significant (P<0.05 functional relations were found between the chemical characteristics and percentage of Capsella bursa pastoris (L. Medic. participation in the lucerne sward, and forage quality. These relations indicated a multiple practical relevance and a necessity to control Capsella bursa pastoris (L. Medic. in lucerne stands in order to decrease weed density and improve forage quality.

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

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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.

Environmental impact assessment of alfalfa (Medicago sativa L.) hay production.

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Bacenetti, Jacopo; Lovarelli, Daniela; Tedesco, Doriana; Pretolani, Roberto; Ferrante, Valentina

2018-09-01

On-farm production of hay and high-protein-content feed has several advantages such as diversification of on-farm cultivated crops, reduction of off-farm feed concentrates transported over long distances and a reduction in runoff during the winter season if grown crops are perennial. Among those crops cultivated for high-protein-content feed, alfalfa (Medicago sativa L.) is one of the most important in the Italian context. Nevertheless, up to now, only a few studies have assessed the environmental performance of alfalfa hay production. In this study, using the Life Cycle Assessment approach, the environmental impact of alfalfa hay production in Northern Italy was analyzed. More in detail, two production practices (without and with irrigation) were compared. The results show that alfalfa hay production in irrigated fields has a better environmental performance compared to non-irrigated production, mainly because of the yield increase achieved with irrigation. In particular, for the Climate Change impact category, the impact is equal to 84.54 and 80.21kgCO 2 /t of hay for the scenario without and with irrigation, respectively. However, for two impact categories (Ozone Depletion and Human Toxicity-No Cancer Effect), the impact of irrigation completely offsets the yield increase, and the cultivation practice without irrigation shows the best environmental performance. For both scenarios, the mechanization of harvest is the main environmental hotspot, mostly due to fuel consumption and related combustion emissions. Wide differences were highlighted by comparing the two scenarios with the Ecoinvent process of alfalfa hay production; these differences are mostly due to the cultivation practice and, in particular, to the more intensive fertilization in Swiss production. Copyright © 2018 Elsevier B.V. All rights reserved.

Genetic transformation and analysis of rice OsAPx2 gene in Medicago sativa.

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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.

Nonphotosynthetic CO2 fixation by alfalfa (Medicago sativa L.) roots and nodules

International Nuclear Information System (INIS)

Anderson, M.P.; Heichel, G.H.; Vance, C.P.

1987-01-01

The dependence of alfalfa (Medicago sativa L.) root and nodule nonphotosynthetic CO 2 fixation on the supply of currently produced photosynthate and nodule nitrogenase activity was examined a various times after phloem-girdling and exposure of nodules to Ar:O 2 . Phloem-girdling was effected 20 hours and exposure to Ar:O 2 was effected 2 to 3 hours before initiation of experiments. Nodule and root CO 2 fixation rates of phloem-girdled plants were reduced to 38 and 50%, respectively, of those of control plants. Exposure to Ar:O 2 decreased nodule CO 2 fixation rates to 45%, respiration rates to 55%, and nitrogenase activities to 51% of those of the controls. The products of nodule CO 2 fixation were exported through the xylem to the shoot mainly as amino acids within 30 to 60 minutes after exposure to 14 CO 2 . In contrast to nodules, roots exported very little radioactivity, and most of the 14 C was exported as organic acids. The nonphotosynthetic CO 2 fixation rate of roots and nodules averaged 26% of the gross respiration rate, i.e. the sum of net respiration and nonphotosynthetic CO 2 assimilation. Nodules fixed CO 2 at a rate 5.6 times that of roots, but since nodules comprised a small portion of root system mass, roots accounted for 76% of the nodulated roots system CO 2 fixation. The results indicate that nodule CO 2 fixation in alfalfa is associated with N assimilation

Effects of simulated acidic rain on yields of Raphanus sativus, Lactuca sativa, Triticum aestivum and Medicago sativa

Energy Technology Data Exchange (ETDEWEB)

Evans, L.S.; Gmur, N.F.; Mancini, D.

1982-01-01

Experiments were performed to determine effects to simulated acidic rain on radishes (Raphanus sativus), lettuce (Lactuca sativa), wheat (Triticum aestivum) and alfalfa (Medicago sativa) grown under greenhouse conditions. Experimental designs allowed the detection of statistically significant differences among means that differed by less than 10%. Simulated rainfalls of 2.5, 25, 63, 398, 100 and 2512 ..mu..eq H/sup +/ 1/sup -1/ (pH 5.6, 4.6, 4.2, 3.4, 3.0 and 2.6, respectively) decreased root yields (fresh mass) of radishes 26, 42, 37, 41, 66 and 73% compared with plants not exposed to rainfalls, Similar reductions were present in radish shoot fresh mass, leaf area, and root diameter. Fresh mass yields of lettuce plants exposed to 100, 794 and 1995 ..mu..eq H/sup +/ 1/sup -1/ (pH 4.0, 3.1 and 2.7, respectively) were 11, 10 and 14%, respectively, below heads of plants not exposed to rainfalls. Yields of plants exposed to simulated rainfalls of 2.0 ..mu..eq H/sup +/ 1/sup -1/ (pH 5.7) were similar to plants not exposed to rainfalls. Although visible foliar injury occurred to lettuce, this injury was present only on wrapper leaves and would not affect marketable quality. Yields of wheat which were applied during anthesis and caryopsis development were not influenced by exposure to 46 simulated rainfalls even as high as 1996 ..mu..eq H/sup +/ 1/sup -1/ (pH 2.7). Alfalfa plants exhibited no overall differences in fresh mass of forage among treatments even after 57 simulated rainfalls of 1996 ..mu..eq H/sup +/ 1/sup -1/ (pH 2.7) over 105 days. 22 references, 2 figures, 7 tables.

Correlations between environmental factors and wild bee behavior on alfalfa (Medicago sativa) in northwestern China.

Science.gov (United States)

Wang, Xiaojuan; Liu, Hongping; Li, Xiaoxia; Song, Yu; Chen, Li; Jin, Liang

2009-10-01

To discover the effect of environmental factors on pollinator visitation to flowering Medicago sativa, several field experiments were designed to examine the diurnal movement patterns of wild bee species in the Hexi Corridor of northwestern China. Our study results showed that Megachile abluta, M. spissula, and Xylocopa valga showed unimodal diurnal foraging behavior, whereas Andrena parvula and Anthophora melanognatha showed bimodal diurnal foraging behavior. Correlation analysis indicated that diurnal foraging activities of pollinators were significantly correlated with environmental factors. Correlations of foraging activities versus environmental factors for M. abluta, M. spissula, and X. valga best fit a linear model, whereas those of A. parvula and A. melanognatha best fit a parallel quadratic model. Results of this study indicated that solitary wild bees such as M. abluta, M. spissula, X. valga, A. parvula, and A. melanognatha are potential alfalfa pollinators in the Hexi Corridor. An understanding of the environmental factors that affect the behaviors of different wild bees foraging in alfalfa are basic to the utilization of solitary wild bees in a practical way for increased, or more consistent, pollination of alfalfa for seed production.

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

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.

Effect of Medicago sativa L. and compost on organic and inorganic pollutant removal from a mixed contaminated soil and risk assessment using ecotoxicological tests.

Science.gov (United States)

Marchand, Charlotte; Hogland, William; Kaczala, Fabio; Jani, Yahya; Marchand, Lilian; Augustsson, Anna; Hijri, Mohamed

2016-11-01

Several Gentle Remediation Options (GRO), e.g., plant-based options (phytoremediation), singly and combined with soil amendments, can be simultaneously efficient for degrading organic pollutants and either stabilizing or extracting trace elements (TEs). Here, a 5-month greenhouse trial was performed to test the efficiency of Medicago sativa L., singly and combined with a compost addition (30% w/w), to treat soils contaminated by petroleum hydrocarbons (PHC), Co and Pb collected at an auto scrap yard. After 5 months, total soil Pb significantly decreased in the compost-amended soil planted with M. sativa, but not total soil Co. Compost incorporation into the soil promoted PHC degradation, M. sativa growth and survival, and shoot Pb concentrations [3.8 mg kg(-1) dry weight (DW)]. Residual risk assessment after the phytoremediation trial showed a positive effect of compost amendment on plant growth and earthworm development. The O2 uptake by soil microorganisms was lower in the compost-amended soil, suggesting a decrease in microbial activity. This study underlined the benefits of the phytoremediation option based on M. sativa cultivation and compost amendment for remediating PHC- and Pb-contaminated soils.

Medicago truncatula SOC1 Genes Are Up-regulated by Environmental Cues That Promote Flowering

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Jared B. Fudge

2018-04-01

Full Text Available Like Arabidopsis thaliana, the flowering of the legume Medicago truncatula is promoted by long day (LD photoperiod and vernalization. However, there are differences in the molecular mechanisms involved, with orthologs of two key Arabidopsis thaliana regulators, FLOWERING LOCUS C (FLC and CONSTANS (CO, being absent or not having a role in flowering time function in Medicago. In Arabidopsis, the MADS-box transcription factor gene, SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (AtSOC1, plays a key role in integrating the photoperiodic and vernalization pathways. In this study, we set out to investigate whether the Medicago SOC1 genes play a role in regulating flowering time. Three Medicago SOC1 genes were identified and characterized (MtSOC1a–MtSOC1c. All three MtSOC1 genes, when heterologously expressed, were able to promote earlier flowering of the late-flowering Arabidopsis soc1-2 mutant. The three MtSOC1 genes have different patterns of expression. However, consistent with a potential role in flowering time regulation, all three MtSOC1 genes are expressed in the shoot apex and are up-regulated in the shoot apex of plants in response to LD photoperiods and vernalization. The up-regulation of MtSOC1 genes was reduced in Medicago fta1-1 mutants, indicating that they are downstream of MtFTa1. Insertion mutant alleles of Medicago soc1b do not flower late, suggestive of functional redundancy among Medicago SOC1 genes in promoting flowering.

Molecular Diversity and Population Structure of a Worldwide Collection of Cultivated Tetraploid Alfalfa (Medicago sativa subsp. sativa L.) Germplasm as Revealed by Microsatellite Markers.

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Qiang, Haiping; Chen, Zhihong; Zhang, Zhengli; Wang, Xuemin; Gao, Hongwen; Wang, Zan

2015-01-01

Information on genetic diversity and population structure of a tetraploid alfalfa collection might be valuable in effective use of the genetic resources. A set of 336 worldwide genotypes of tetraploid alfalfa (Medicago sativa subsp. sativa L.) was genotyped using 85 genome-wide distributed SSR markers to reveal the genetic diversity and population structure in the alfalfa. Genetic diversity analysis identified a total of 1056 alleles across 85 marker loci. The average expected heterozygosity and polymorphism information content values were 0.677 and 0.638, respectively, showing high levels of genetic diversity in the cultivated tetraploid alfalfa germplasm. Comparison of genetic characteristics across chromosomes indicated regions of chromosomes 2 and 3 had the highest genetic diversity. A higher genetic diversity was detected in alfalfa landraces than that of wild materials and cultivars. Two populations were identified by the model-based population structure, principal coordinate and neighbor-joining analyses, corresponding to China and other parts of the world. However, lack of strictly correlation between clustering and geographic origins suggested extensive germplasm exchanges of alfalfa germplasm across diverse geographic regions. The quantitative analysis of the genetic diversity and population structure in this study could be useful for genetic and genomic analysis and utilization of the genetic variation in alfalfa breeding.

The lipoxygenase gene family: a genomic fossil of shared polyploidy between Glycine max and Medicago truncatula

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Choi Beom-Soon

2008-12-01

Full Text Available Abstract Background Soybean lipoxygenases (Lxs play important roles in plant resistance and in conferring the distinct bean flavor. Lxs comprise a multi-gene family that includes GmLx1, GmLx2 and GmLx3, and many of these genes have been characterized. We were interested in investigating the relationship between the soybean lipoxygenase isozymes from an evolutionary perspective, since soybean has undergone two rounds of polyploidy. Here we report the tetrad genome structure of soybean Lx regions produced by ancient and recent polyploidy. Also, comparative genomics with Medicago truncatula was performed to estimate Lxs in the common ancestor of soybean and Medicago. Results Two Lx regions in Medicago truncatula showing synteny with soybean were analyzed. Differential evolutionary rates between soybean and Medicago were observed and the median Ks values of Mt-Mt, Gm-Mt, and Gm-Gm paralogs were determined to be 0.75, 0.62, and 0.46, respectively. Thus the comparison of Gm-Mt paralogs (Ks = 0.62 and Gm-Mt orthologs (Ks = 0.45 supports the ancient duplication of Lx regions in the common ancestor prior to the Medicago-Glycine split. After speciation, no Lx regions generated by another polyploidy were identified in Medicago. Instead tandem duplication of Lx genes was observed. On the other hand, a lineage-specific duplication occurred in soybean resulting in two pairs of Lx regions. Each pair of soybean regions was co-orthologous to one Lx region in Medicago. A total of 34 Lx genes (15 MtLxs and 19 GmLxs were divided into two groups by phylogenetic analysis. Our study shows that the Lx gene family evolved from two distinct Lx genes in the most recent common ancestor. Conclusion This study analyzed two pairs of Lx regions generated by two rounds of polyploidy in soybean. Each pair of soybean homeologous regions is co-orthologous to one region of Medicago, demonstrating the quartet structure of the soybean genome. Differential evolutionary rates between

Cytotoxicity and apoptosis induced by alfalfa (Medicago sativa) leaf extracts in sensitive and multidrug-resistant tumor cells.

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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.

Nodulation by Sinorhizobium meliloti originated from a mining soil alleviates Cd toxicity and increases Cd-phytoextraction in Medicago sativa L.

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Ghnaya, Tahar; Mnassri, Majda; Ghabriche, Rim; Wali, Mariem; Poschenrieder, Charlotte; Lutts, Stanley; Abdelly, Chedly

2015-01-01

Besides their role in nitrogen supply to the host plants as a result of symbiotic N fixation, the association between legumes and Rhizobium could be useful for the rehabilitation of metal-contaminated soils by phytoextraction. A major limitation presents the metal-sensitivity of the bacterial strains. The aim of this work was to explore the usefulness of Sinorhizobium meliloti originated from a mining site for Cd phytoextraction by Medicago sativa. Inoculated and non-inoculated plants were cultivated for 60 d on soils containing 50 and/or 100 mg Cd kg(-1) soil. The inoculation hindered the occurrence of Cd- induced toxicity symptoms that appeared in the shoots of non-inoculated plants. This positive effect of S. meliloti colonization was accompanied by an increase in biomass production and improved nutrient acquisition comparatively to non-inoculated plants. Nodulation enhanced Cd absorption by the roots and Cd translocation to the shoots. The increase of plant biomass concomitantly with the increase of Cd shoot concentration in inoculated plants led to higher potential of Cd-phytoextraction in these plants. In the presence of 50 mg Cd kg(-1) in the soil, the amounts of Cd extracted in the shoots were 58 and 178 μg plant(-1) in non-inoculated and inoculated plants, respectively. This study demonstrates that this association M. sativa-S. meliloti may be an efficient biological system to extract Cd from contaminated soils.

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

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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.

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

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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.

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

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Rosellini, Daniele; Ferradini, Nicoletta; Allegrucci, Stefano; Capomaccio, Stefano; Zago, Elisa Debora; Leonetti, Paola; Balech, Bachir; Aversano, Riccardo; Carputo, Domenico; Reale, Lara; Veronesi, Fabio

2016-04-07

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. Copyright © 2016 Rosellini et al.

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

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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.

Soil bulk electrical resistivity and forage ground cover: nonlinear models in an alfalfa (Medicago sativa L. case study

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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.

The arbuscular mycorrhizal fungus Glomus mosseae gives contradictory effects on phosphorus and arsenic acquisition by Medicago sativa Linn

International Nuclear Information System (INIS)

Chen Baodong; Xiao Xueyi; Zhu Yongguan; Smith, F. Andrew; Miao Xie, Z.; Smith, Sally E.

2007-01-01

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

Cell suspension culture and mutants selection for resistance to PEG induced water stress in alfalfa (Medicago sativa L.)

International Nuclear Information System (INIS)

Zhang Xiaodong; Lin Tingan

1994-01-01

Elements affecting suspension cell culture in alfalfa (Medicago sativa L.) were studied and a method of rapid establishment of embryogenic suspension cell lines was introduced. Effects of γ ray irradiation on the growth of suspension cells were studied, and the optimum dose of irradiation for inducing mutants from suspension cells was about 20 ∼ 60 Gy. Effects of PEG and NaCl induced water stress on the growth of suspension cells were also investigated, and the results showed that the congregants of preliminary suspension culture were more susceptible than the established suspension cell lines. With 20 Gy of γ ray irradiation on suspension cell line (JL416), six clones were obtained with 70 days of selection on medium of 15% PEG (about-11 bar). A number of regenerated plants were obtained from these clones. One clone was also gained from medium containing 20% PEG (about-15 bar). The selected mutant cell lines (JP15 and JP20) has strong resistances to high concentration of PEG and NaCl induced water stress

Occurrence of Transgenic Feral Alfalfa (Medicago sativa subsp. sativa L.) in Alfalfa Seed Production Areas in the United States.

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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.

Activity of Saponins from Medicago species Against HeLa and MCF-7 Cell Lines and their Capacity to Potentiate Cisplatin Effect.

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Avato, Pinarosa; Migoni, Danilo; Argentieri, Mariapia; Fanizzi, Francesco P; Tava, Aldo

2017-11-24

Saponins from Medicago species display several biological activities, among them apoptotic effects against plant cells have been evidenced. In contrast, their cytotoxic and antitumor activity against animal cells have not been studied in great details. To explore the cytotoxic properties of saponin from Medicago species against animal cells and their effect in combination with the antitumoral drug cisplatin. Cytotoxic activity of saponin mixtures from M. arabica (tops and roots), M. arborea (tops) and M. sativa (tops, roots and seeds) and related prosapogenins from M. arborea and M. sativa (tops) against HeLa and MCF-7 cell lines is described. In addition, cytotoxicity of soyasaponin I and purified saponins (1-8) of hederagenin, medicagenic and zanhic acid is also presented. Combination experiments with cisplatin have been also conducted. Saponins from M. arabica tops and roots (mainly monodesmosides of hederagenin and bayogenin) were the most effective to reduce proliferation of HeLa and MCF-7 cell lines. Among the purified saponins, the most cytotoxic was saponin 1, 3-O-ß-D-glucopyranosyl(1→2)-α-L-arabinopyranosyl hederagenin. When saponins, derived prosapogenins and pure saponins were used in combination with cisplatin, they all, to different extent, were able to potentiate cisplatin activity against HeLa cells but not against MCF-7 cell lines. Moreover uptake of cisplatin in these cell lines was significantly reduced. Overall results showed that specific molecular types of saponins (hederagenin glycosides) have potential as anti-cancer agents or as leads for anti-cancer agents. Moreover saponins from Medicago species have evidenced interesting properties to mediate cisplatin effects in tumor cell lines. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

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

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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.

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

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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.

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

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

2016-01-01

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

Spatio-Temporal Expression Patterns of Arabidopsis thaliana and Medicago truncatula Defensin-Like Genes

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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. PMID:23527067

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

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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.

Nutritive evaluation of Medicago truncutula (cv. jernalong) pasture ...

African Journals Online (AJOL)

Nutritive evaluation of Medicago truncutula (cv. jernalong) pasture for sheep. 1. Seasonal .... obtained by laboratory work, using in vitro techniques. (Engels et al. .... model that was used to explain 92,3% of the variance in. IVDOM content.

The arbuscular mycorrhizal fungus Glomus mosseae gives contradictory effects on phosphorus and arsenic acquisition by Medicago sativa Linn

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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.

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.

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.

Development of manganese toxicity in pasture legumes under extreme climatic conditions. [Trifolium subterraneum; Medicago sativa; Brassica campestris

Energy Technology Data Exchange (ETDEWEB)

Siman, A; Cradock, F W; Hudson, A W

1974-08-01

Manganese levels and pH in soil were measured on limed and unlimed plots at bi-monthly intervals for two years at five field sites with lucerne (Medicago sativa) and subterranean clover (Trifolium subterraneum) and related to rainfall and temperature. Pot experiments with lucerne, subterranean clover and rape (Brassica campestris) were used to confirm the results of the field experiments. Manganese toxicity developed in lucerne and subterranean clover under waterlogged conditions after heavy rain on the slightly acid soils (pH 4.7-5.5). Lucerne also showed manganese toxicity on the same soils in summer after extended hot, dry conditions. The maximum available manganese was 210 ..mu..g/g in the waterlogged soil (0-15 cm) the 128 ..mu..g/g in the heat affected soil. Lime treatment of 2240 kg/ha reduced the maximum available manganese to 148 ..mu..g/g in waterlogged plots and to 47 ..mu..g/g in the heat affected plots but failed to correct manganese toxicity. However, lime corrected toxicity symptoms under less severe conditions. In the pot experiments, available manganese reached 270 ..mu..g/g after 2 weeks artificial waterlogging and 68 ..mu..g/g after 2 weeks dry heat exposure. 12 references, 4 figures, 3 tables.

In vitro regeneration of some Iranian alfalfa (Medicago sativa L. genotypes via somatic embryogenesis

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Majid Shokrpour

2014-12-01

Full Text Available An effective in vitro regeneration system is one of the prerequisites for genetic manipulation of alfalfa (Medicago sativa L. varieties and genotypes. In this research, somatic embryogenesis of four alfalfa genotypes, 6-18 (synthetic, 4-14 (Kara Yonje- Karakozlu, 3-27 (Kara Yonje Maraghe and y-6 (Regen-SY, were investigated using leaf and petiole explants. Formation of callus and somatic embryogenesis was significantly influenced by the explant type and interaction of genotype and culture medium. Petiole explants of genotype 4-14 produced the highest yield of callus (0.406 gr fresh weight of callus. Percentage of somatic embryogenesis and the number of embryos per callus in petiole explants of genotype 4-14 was higher than those of other genotypes and explants. In genotype 6-18, the highest percentage of somatic embryogenesis was achieved on MS medium containing 5 mg/L 2,4-D and 2 mg/L kinetin. There was no significant differences between genotypes and explants in terms of embryo conversion to plantlet, and on average, 58% of somatic embryos converted to plantlet on MS medium. The petiole explants of genotype 6-18 did not exhibit somatic embryogenesis response in medium containing low ratio of 2,4-D:Kinetin (5 mg/L 2,4-D and 2 mg/L kinetin. While, these explants showed somatic embryogenesis in higher ratio of 2,4-D:Kinetin (5:1. The plantlet conversion efficiency of somatic embryos produced through this study was relatively higher and therefore, the method presented in this study could be used in alfalfa genetic manipulation and molecular studies.

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).

Sequence divergence of microsatellites for phylogeographic assessment of Moroccan Medicago species.

Science.gov (United States)

Zitouna, N; Marghali, S; Gharbi, M; Haddioui, A; Trifi-Farah, N

2014-03-12

Six Medicago species were investigated to characterize and valorize plant genetic resources of pastoral interest in Morocco. Samples were obtained from the core collection of the South Australian Research and Development Institute (SARDI). The transferability of single sequence repeat markers of Medicago truncatula was successful with 97.6% efficiency across the five species. A total of 283 alleles and 243 genotypes were generated using seven SSR markers, confirming the high level of polymorphism that is characteristic of the Medicago genus, despite a heterozygosity deficit (HO = 0.378; HE = 0.705). In addition, a high level of gene flow was revealed among the species analyzed with significant intra-specific variation. The unweighted pair group method with arithmetic mean dendrogram generated by the dissimilarity matrix revealed that M. polymorpha and M. orbicularis are closely related, and that M. truncatula is likely the ancestral species. The Pearson correlation index revealed no significant correlations between the geographic distribution of the Moroccan species and genetic similarities, indicating local adaptation of these species to different ecological environments independent of their topographical proximities. The substantial genetic variation observed was likely due to the predominance of selfing species, the relative proximity of prospected sites, human impacts, and the nature of the SARDI core collections, which are selected for their high genetic diversity. The results of this first report on Moroccan Medicago species will be of great interest for establishing strategies aiming at reasonable management and selection programs for local and Mediterranean germplasm in the face of increasing environmental change.

Over-Expression of Arabidopsis EDT1 Gene Confers Drought Tolerance in Alfalfa (Medicago sativa L.

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Guangshun Zheng

2017-12-01

Full Text Available Alfalfa (Medicago sativa L. is an important legume forage crop with great economic value. However, as the growth of alfalfa is seriously affected by an inadequate supply of water, drought is probably the major abiotic environmental factor that most severely affects alfalfa production worldwide. In an effort to enhance alfalfa drought tolerance, we transformed the Arabidopsis Enhanced Drought Tolerance 1 (AtEDT1 gene into alfalfa via Agrobacterium-mediated transformation. Compared with wild type plants, drought stress treatment resulted in higher survival rates and biomass, but reduced water loss rates in the transgenic plants. Furthermore, transgenic alfalfa plants had increased stomatal size, but reduced stomatal density, and these stomatal changes contributed greatly to reduced water loss from leaves. Importantly, transgenic alfalfa plants exhibited larger root systems with larger root lengths, root weight, and root diameters than wild type plants. The transgenic alfalfa plants had reduced membrane permeability and malondialdehyde content, but higher soluble sugar and proline content, higher superoxide dismutase activity, higher chlorophyll content, enhanced expression of drought-responsive genes, as compared with wild type plants. Notably, transgenic alfalfa plants grew better in a 2-year field trial and showed enhanced growth performance with increased biomass yield. All of our morphological, physiological, and molecular analyses demonstrated that the ectopic expression of AtEDT1 improved growth and enhanced drought tolerance in alfalfa. Our study provides alfalfa germplasm for use in forage improvement programs, and may help to increase alfalfa production in arid lands.

Sinorhizobium meliloti can protect Medicago truncatula against Phoma medicaginis attack

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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.

Strontium-90 in alfalfa (Medicago sativa) around the Hanford site in southeastern Washington state: an evaluation of surveillance data

International Nuclear Information System (INIS)

Poston, T.M.; Jaquish, R.E.; Antonio, E.J.; Patton, G.W.

1998-01-01

From 1988–1994, 90 Sr concentrations in alfalfa (Medicago sativa) grown in areas receiving irrigation water from the Columbia River downstream of Hanford have exceeded concentrations observed in alfalfa grown nearby using other irrigation water sources. Surveillance data indicate that the relationship is not linked to atmospheric releases from Hanford. Attributing the apparent differences in 90 Sr concentrations to irrigation water is equivocal. Evaluations of 90 Sr in Columbia River water fail to consistently show a statistically significant (P > 0.05) contribution at locations immediately downstream of Hanford. Modeling of past 90 Sr fallout accumulation in soil indicates that the potential contribution from Hanford liquid effluents entering the Columbia River, subsequently used as irrigation water from 1972 to 1992, would account for ~ 2% of 90 Sr in soil. The remaining 98% arises from historic atomic weapons testing fallout. Radiological doses modeled for an alfalfa-cow's milk-human pathway indicate that the maximum 50 year effective dose equivalent to a standard man who consumes 270 l of milk per year was 0.9 μSv, which is < 0.03% of the 3 mSv annual dose resulting from natural sources of radiation exposure

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.

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

STUDY ON PHYTOEXTRACTION BALANCE OF ZN, CD, PB FROM MINE-WASTE POLLUTED SOILS BY USING MEDICAGO SATIVA AND TRIFOLIUM PRATENSE SPECIES

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B. LIXANDRU

2009-05-01

Full Text Available For a term of two years was studied phytoextractive potential of Zn, Cd and Pb using successive culture of alfalfa (Medicago sativa and red clover (Trifolium pratense. In the experimental plot was incorporated a quantity of 20 kg mine waste per square meter, providing in soil 1209 mg Zn/kg d.s., 4.70 mg Cd/kg d.s. and 188.2 mg Pb/kg d.s. The metals content accumulated in plants was determined at the two moments of biomass harvesting, and through balance calculations we could establish the phytoextraction efficiency of the two forage-grasses species. The obtained results indicate that both perennial forage-legumes species have a good phytoextractive capacity and tolerance for Zn and Pb, especially Trifolium pratense specie. By using this species as phytoextractors on soil polluted with 3.76 times more Pb and 4.03 times more Zn, is provided the reduction of metallic ions concentration in soil to limits admitted by laws in a period of 3, respectively, 4 years.

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.

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

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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.

Effects of compost organic amendments on chemical composition and in vitro digestibility of alfalfa (Medicago sativa L.

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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.

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.

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.

Effects of Sludge Compost on EC value of Saline Soil and Plant Height of Medicago

Science.gov (United States)

Sun, Chongyang; Zhao, Ke; Chen, Xing; Wang, Xiaohui

2017-12-01

In this study, the effects of sludge composting on the EC value of saline soil and the response to Medicago plant height were studied by planting Medicago with pots for 45 days in different proportions as sludge composting with saline soil. The results showed that the EC value of saline soil did not change obviously with the increase of fertilization ratio,which indicated that the EC value of saline soil was close to that of the original soil. The EC decreased by 31.45% at fertilization ratio of 40%. The height of Medicago reached the highest at 40% fertilization ratio, and that was close to 60% fertilization ratio, and the difference was significant with other treatments. By comprehensive analyse and compare,the optimum application rate of sludge compost was 40% under this test condition.

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

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

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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.

Producción de biomasa aérea y uso equivalente de la tierra en intercultivos de alfalfa (Medicago sativa L.

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T. W Pereyra

Full Text Available Tradicionalmente, el incremento de la productividad se ha asociado al aumento del rendimiento a través del mejoramiento genético y las prácticas de manejo del cultivo. Sin embargo, si se considera la producción por unidad de área y de tiempo, el sistema de intercultivos puede ser otra forma de mejorar la rentabilidad. El objetivo del experimento fue determinar la biomasa producida y el uso equivalente de la tierra en monocultivo e intercultivos de alfalfa (Medicago sativa L. con sorgo sudán (Sorghum sudanense L. y avena (Avena sativa L.. Se determinó la biomasa aérea de todos los tratamientos (expresada por unidad de superficie y el uso equivalente de la tierra. El diseño fue completamente aleatorizado, dispuesto en bloques con dos repeticiones. Los resultados se sometieron a un ANOVA y las medias se compararon mediante la prueba de Duncan, a través del paquete estadístico INFOSTAT. El intercultivo alfalfa-sorgo triplicó la producción de alfalfa en relación con el monocultivo, mientras que alfalfa-avena no superó la producción de alfalfa pura en los meses de invierno. El intercultivo alfalfa-sorgo fue un 57 % más eficiente en el uso de la tierra que sus respectivos monocultivos, mientras que alfalfa-avena no logró superar la unidad.

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.

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.

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

International Nuclear Information System (INIS)

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

2011-01-01

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. - 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.

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

KAUST Repository

Kamphuis, L. G.; Lichtenzveig, J.; Peng, K.; Guo, S.-M.; Klingler, John; Siddique, K. H. M.; Gao, L.-L.; Singh, K. B.

2013-01-01

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.

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.

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

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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

A community resource for high-throughput quantitative RT-PCR analysis of transcription factor gene expression in Medicago truncatula

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Redman Julia C

2008-07-01

Full Text Available Abstract Background Medicago truncatula is a model legume species that is currently the focus of an international genome sequencing effort. Although several different oligonucleotide and cDNA arrays have been produced for genome-wide transcript analysis of this species, intrinsic limitations in the sensitivity of hybridization-based technologies mean that transcripts of genes expressed at low-levels cannot be measured accurately with these tools. Amongst such genes are many encoding transcription factors (TFs, which are arguably the most important class of regulatory proteins. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR is the most sensitive method currently available for transcript quantification, and one that can be scaled up to analyze transcripts of thousands of genes in parallel. Thus, qRT-PCR is an ideal method to tackle the problem of TF transcript quantification in Medicago and other plants. Results We established a bioinformatics pipeline to identify putative TF genes in Medicago truncatula and to design gene-specific oligonucleotide primers for qRT-PCR analysis of TF transcripts. We validated the efficacy and gene-specificity of over 1000 TF primer pairs and utilized these to identify sets of organ-enhanced TF genes that may play important roles in organ development or differentiation in this species. This community resource will be developed further as more genome sequence becomes available, with the ultimate goal of producing validated, gene-specific primers for all Medicago TF genes. Conclusion High-throughput qRT-PCR using a 384-well plate format enables rapid, flexible, and sensitive quantification of all predicted Medicago transcription factor mRNAs. This resource has been utilized recently by several groups in Europe, Australia, and the USA, and we expect that it will become the 'gold-standard' for TF transcript profiling in Medicago truncatula.

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

DEFF Research Database (Denmark)

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...... 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...

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

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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.

Soil quality effects on regeneration of annual Medicago pastures in ...

African Journals Online (AJOL)

Annual medic (Medicago spp.) pastures are widely used as the forage component of crop rotation systems in the Mediterranean region of South Africa. Reliable establishment of medics can be challenging. This may be related to poor soil quality, an inherent problem of soils in the region often aggravated by poor ...

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

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

Expression of an alfalfa (Medicago sativa L.) peroxidase gene in transgenic Arabidopsis thaliana enhances resistance to NaCl and H2O2.

Science.gov (United States)

Teng, K; Xiao, G Z; Guo, W E; Yuan, J B; Li, J; Chao, Y H; Han, L B

2016-05-23

Peroxidases (PODs) are enzymes that play important roles in catalyzing the reduction of H2O2 and the oxidation of various substrates. They function in many different and important biological processes, such as defense mechanisms, immune responses, and pathogeny. The POD genes have been cloned and identified in many plants, but their function in alfalfa (Medicago sativa L.) is not known, to date. Based on the POD gene sequence (GenBank accession No. L36157.1), we cloned the POD gene in alfalfa, which was named MsPOD. MsPOD expression increased with increasing H2O2. The gene was expressed in all of the tissues, including the roots, stems, leaves, and flowers, particularly in stems and leaves under light/dark conditions. A subcellular analysis showed that MsPOD was localized outside the cells. Transgenic Arabidopsis with MsPOD exhibited increased resistance to H2O2 and NaCl. Moreover, POD activity in the transgenic plants was significantly higher than that in wild-type Arabidopsis. These results show that MsPOD plays an important role in resistance to H2O2 and NaCl.

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 events of legume ... molecular mechanism of stress responses of AP2/EREBPs. ..... comprehensive profiling of developmental, hormonal or ... interactions with other organisms, plant development and stress.

Mycorrhizal Glomus spp. vary in their effects on the dynamics and turnover of fine alfalfa (Medicago sativa L.) roots

International Nuclear Information System (INIS)

Ren, A.; Waly, N.; Chunhui, M.; Zhang, Q.; Liu, H.; Yang, J.

2016-01-01

The distribution of fine roots in the soil profile has important implications related to water and nutrient uptake. The Objective of this study was to compare the effects of different arbuscular mycorrhizal fungi (AMF) on the fine root dynamics of Medicago sativa L. cv. Sanditi. We used minirhizotrons to observe changes in fine root length density (FRLD, mm/cm2) and fine root surface area density (FRSAD, mm2/cm2) during the growing season. Fine root P concentrations and turnover rate were also measured. The colonization rate of fine roots varied depending on the AMF species. Colonization rates were highest when roots were inoculated with Glomus mosseae and lowest when roots were inoculated G. intraradices. Inoculation with AMF significantly increased both FRLD and FRSAD. G. versiforme increased FRLD and FRSAD most, whereas G. mosseae had the least effect. Inoculation with AMF also decreased fine root turnover rates. Inoculation with a mixture of AMF species increased fine root turnover and P concentrations more than inoculation with a single AMF species. Fine root length density increased to a maximum on Aug. 6 and then decreased. In comparison, FRSAD exhibited two peaks during the growing season. Overall, the Results indicated that inoculation with AMF can significantly promote fine root growth and P uptake by alfalfa growing on soil with low P availability. The AMF may preserve fine root function late in the growing season. (author)

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

Science.gov (United States)

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

2016-03-25

Drought and high salinity are two major abiotic factors that restrict alfalfa productivity. A dehydrin protein, CsLEA, from the desert grass Cleistogenes songorica was transformed into alfalfa (Medicago sativa L.) via Agrobacterium-mediated transformation using the bar gene as a selectable marker, and the drought and salt stress tolerances of the transgenic plants were assessed. Thirty-nine of 119 transformants were positive, as screened by Basta, and further molecularly authenticated using PCR and RT-PCR. Phenotype observations revealed that the transgenic plants grew better than the wild-type (WT) plants after 15d of drought stress and 10d of salt stress: the leaves of WT alfalfa turned yellow, whereas the transgenic alfalfa leaves only wilted; after rewatering, the transgenic plants returned to a normal state, though the WT plants could not be restored. Evaluation of physiologic and biochemical indices during drought and salt stresses showed a relatively lower Na(+) content in the leaves of the transgenic plants, which would reduce toxic ion effects. In addition, the transgenic plants were able to maintain a higher relative water content (RWC), higher shoot biomass, fewer photosystem changes, decreased membrane injury, and a lower level of osmotic stress injury. These results demonstrate that overexpression of the CsLEA gene can enhance the drought and salt tolerance of transgenic alfalfa; in addition, carrying the bar gene in the genome may increase herbicide resistance. Copyright © 2016 Elsevier Inc. All rights reserved.

WATER DEFICIT EFFECT ON YIELD AND FORAGE QUALITY OF MEDICAGO SATIVA POPULATIONS UNDER FIELD CONDITIONS IN MARRAKESH AREA (MOROCCO

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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.

Microsynteny between pea and Medicago truncatula in the SYM2 region

NARCIS (Netherlands)

Gualtieri, G.; Kulikova, O.; Limpens, E.; Kim, D.J.; Cook, D.R.; Bisseling, T.; Geurts, R.

2002-01-01

The crop legume pea (Pisum sativum) is genetically well characterized. However, due to its large genome it is not amenable to efficient positional cloning strategies. The purpose of this study was to determine if the model legume Medicago truncatula, which is a close relative of pea, could be used

Evaluation of microbial biomass C and N content of the soils cultivated with vetch (Vicia sativa L. and alfalfa (Medicago sativa L.

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İlyas Bolat

2016-01-01

Full Text Available Legume forage crops have the ability of retaining free nitrogen in the air through symbiotic Rhizobium bacteria found in their roots. Additionally, microbial biomass (MB–an essential living component of soil and a significant factor influencing plant nutrient dynamics–is considered to be accurate indicator of soil’s biological condition. Given the aforementioned aspects, soil MB C (Cmic and MB N (Nmic of different legume forage crops were investigated in this study. Soil samples were taken in order to identify certain physical and chemical characteristics of the soil using volume cylinders (0 – 6.5 cm depth from Vicia sativa L. (VSP and Medicago sativa L. planted (MSP areas. To determine the Cmic and Nmic contents, topsoil samples were also taken from 0 – 6.5 cm depth. Cmic and Nmic contents were identified using chloroform – fumigation – extraction method. There was no statistical significance for particle density, bulk density, electrical conductivity, CaCO3 %, and decomposition ratio (Corg/Ntotal of the VSP and MSP soil (P > 0.05. However, some other soil characteristics such as temperature, porosity, sand, silt and clay contents, pH, organic C and total N differed significantly (P < 0.05. Compared to VSP soil, the Cmic contents were determined to be 27 % higher (P < 0.05 in MSP soil. In VSP soil, the soil Nmic content ranged from 83.38 µg g-1 to 124.67 µg g-1, while it ranged from 91.62 µg g-1 to 187.07 µg g-1 in MSP soil. The Nmic content of the MSP soil was observed to be approximately 35 % higher than VSP soil, and a statistically significant difference (P < 0.05 was noticed between the two. Moreover, a significant positive correlation was found not only between the Cmic and organic C contents (r = 0.667; P < 0.05 but also between the Nmic and total N contents of MSP and VSP soil (r = 0.881; P < 0.01. The results of the study revealed that soil Cmic and Nmic values differ as the types of planted legume forage crops

Symbiotic Nitrogen Fixation in Alfalfa (Medicago Sativa L.) by Sinorhizobium Meliloti at Al-Qassim Regions, Saudi Arabia

International Nuclear Information System (INIS)

Al-Barakah, F. N.; Mridha, M. A. U.

2016-01-01

The nodulation status in alfalfa (Medicago sativa L.) plants by Sinorhizobium meliloti under Saudi field condition was assessed in some selected farms in four seasons for two years. In the present study, we also monitored the introduced S. meliloti strains activity under Saudi soil conditions. The samples were collected at regular seasonal intervals from the selected farms. The total number of nodules, morphology of the nodules and the effectiveness of N/sub 2/-fixation was assessed. In general, it was revealed that soils in the selected areas in Saudi Arabia have sufficient bacteria of the proper types to nodulate the alfalfa plants. These nodules are high in number, small in size and white in color. The nodules obtained from most of the selected farms are ineffective for nitrogen fixation. Inoculation of alfalfa seeds with imported S. meliloti strains failed to fix the atmospheric nitrogen sufficiently and also the growth improvement of alfalfa plants. There was a wide variation in the occurrence of number of nodules among the four seasons in two years. It was also observed that summer season severely affected the nodulation making it nearly zero. This low number of nodules exerts a very slow recovery of nodule formation in the next year. The introduced strains were always over competing with the native strains but they did not survive because of hot and dry summer. Nitrogenase activity of the nodules collected from both the inoculated and non-inoculated farms were always very low in all the collected samples, which indicates that the ability of fixing nitrogen by S. meliloti strains in alfalfa under Saudi soils conditions is very low. (author)

Co-expression of bacterial aspartate kinase and adenylylsulfate reductase genes substantially increases sulfur amino acid levels in transgenic alfalfa (Medicago sativa L.).

Science.gov (United States)

Tong, Zongyong; Xie, Can; Ma, Lei; Liu, Liping; Jin, Yongsheng; Dong, Jiangli; Wang, Tao

2014-01-01

Alfalfa (Medicago sativa L.) is one of the most important forage crops used to feed livestock, such as cattle and sheep, and the sulfur amino acid (SAA) content of alfalfa is used as an index of its nutritional value. Aspartate kinase (AK) catalyzes the phosphorylation of aspartate to Asp-phosphate, the first step in the aspartate family biosynthesis pathway, and adenylylsulfate reductase (APR) catalyzes the conversion of activated sulfate to sulfite, providing reduced sulfur for the synthesis of cysteine, methionine, and other essential metabolites and secondary compounds. To reduce the feedback inhibition of other metabolites, we cloned bacterial AK and APR genes, modified AK, and introduced them into alfalfa. Compared to the wild-type alfalfa, the content of cysteine increased by 30% and that of methionine increased substantially by 60%. In addition, a substantial increase in the abundance of essential amino acids (EAAs), such as aspartate and lysine, was found. The results also indicated a close connection between amino acid metabolism and the tricarboxylic acid (TCA) cycle. The total amino acid content and the forage biomass tested showed no significant changes in the transgenic plants. This approach provides a new method for increasing SAAs and allows for the development of new genetically modified crops with enhanced nutritional value.

Co-downregulation of the hydroxycinnamoyl-CoA:shikimate hydroxycinnamoyl transferase and coumarate 3-hydroxylase significantly increases cellulose content in transgenic alfalfa (Medicago sativa L.).

Science.gov (United States)

Tong, Zongyong; Li, Heng; Zhang, Rongxue; Ma, Lei; Dong, Jiangli; Wang, Tao

2015-10-01

Lignin is a component of the cell wall that is essential for growth, development, structure and pathogen resistance in plants, but high lignin is an obstacle to the conversion of cellulose to ethanol for biofuel. Genetically modifying lignin and cellulose contents can be a good approach to overcoming that obstacle. Alfalfa (Medicago sativa L.) is rich in lignocellulose biomass and used as a model plant for the genetic modification of lignin in this study. Two key enzymes in the lignin biosynthesis pathway-hydroxycinnamoyl -CoA:shikimate hydroxycinnamoyl transferase (HCT) and coumarate 3-hydroxylase (C3H)-were co-downregulated. Compared to wild-type plants, the lignin content in the modified strain was reduced by 38%, cellulose was increased by 86.1%, enzyme saccharification efficiency was increased by 10.9%, and cell wall digestibility was increased by 13.0%. The modified alfalfa exhibited a dwarf phenotype, but normal above ground biomass. This approach provides a new strategy for reducing lignin and increasing cellulose contents and creates a new genetically modified crop with enhanced value for biofuel. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Comparative analysis of alfalfa (Medicago sativa L.) leaf transcriptomes reveals genotype-specific salt tolerance mechanisms.

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Lei, Yunting; Xu, Yuxing; Hettenhausen, Christian; Lu, Chengkai; Shen, Guojing; Zhang, Cuiping; Li, Jing; Song, Juan; Lin, Honghui; Wu, Jianqiang

2018-02-15

Soil salinity is an important factor affecting growth, development, and productivity of almost all land plants, including the forage crop alfalfa (Medicago sativa). However, little is known about how alfalfa responds and adapts to salt stress, particularly among different salt-tolerant cultivars. Among seven alfalfa cultivars, we found that Zhongmu-1 (ZM) is relatively salt-tolerant and Xingjiang Daye (XJ) is salt-sensitive. Compared to XJ, ZM showed slower growth under low-salt conditions, but exhibited stronger tolerance to salt stress. RNA-seq analysis revealed 2237 and 1125 differentially expressed genes (DEGs) between ZM and XJ in the presence and absence of salt stress, among which many genes are involved in stress-related pathways. After salt treatment, compared with the controls, the number of DEGs in XJ (19373) was about four times of that in ZM (4833). We also detected specific differential gene expression patterns: In response to salt stress, compared with XJ, ZM maintained relatively more stable expression levels of genes related to the ROS and Ca 2+ pathways, phytohormone biosynthesis, and Na + /K + transport. Notably, several salt resistance-associated genes always showed greater levels of expression in ZM than in XJ, including a transcription factor. Consistent with the suppression of plant growth resulting from salt stress, the expression of numerous photosynthesis- and growth hormone-related genes decreased more dramatically in XJ than in ZM. By contrast, the expression levels of photosynthetic genes were lower in ZM under low-salt conditions. Compared with XJ, ZM is a salt-tolerant alfalfa cultivar possessing specific regulatory mechanisms conferring exceptional salt tolerance, likely by maintaining high transcript levels of abiotic and biotic stress resistance-related genes. Our results suggest that maintaining this specific physiological status and/or plant adaptation to salt stress most likely arises by inhibition of plant growth in ZM through

Translational genomics from model species Medicago truncatula to crop legume Trifolium pratense

NARCIS (Netherlands)

Lang Chunting, Chunting

2012-01-01

The legume Trifolium pratense (red clover) is an important fodder crop and produces important secondary metabolites. This makes red clover an interesting species. In this thesis, the red clover genome is compared to the legume model species Medicago truncatula, of which the

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.

Phytoextraction of rhenium by lucerne (Medicago sativa) and erect milkvetch (Astragalus adsurgens) from alkaline soils amended with coal fly ash.

Science.gov (United States)

He, Honghua; Dong, Zhigang; Pang, Jiayin; Wu, Gao-Lin; Zheng, Jiyong; Zhang, Xingchang

2018-07-15

Coal fly ash (CFA) is an industrial waste generated in huge amounts worldwide, and the management of CFA has become an environmental concern. Recovery of valuable metals from CFA is one of the beneficial reuse options of CFA. Rhenium (Re) is one of the rarest metals in the Earth's crust and one of the most expensive metals of strategic significance in the world market. A CFA at the Jungar Thermal Power Plant, Inner Mongolia, China, contains more Re than two alkaline soils in the surrounding region. Pot experiments were undertaken to grow lucerne (Medicago sativa) and erect milkvetch (Astragalus adsurgens) in a loessial soil and an aeolian sandy soil amended with different rates (5%, 10%, 20%, and 40%) of CFA. The results show that plant growth was considerably enhanced and Re concentration in plants was significantly increased when CFA was applied to the alkaline soils at rates of ≤20%; while in some cases plant growth was also markedly enhanced by the 40% CFA treatment, which increased plant Re concentration the most of all treatments. Both lucerne and erect milkvetch showed potential for phytoextracting Re from CFA-amended alkaline soils. Using CFA for soil amendment not only offers a potential solution for the waste disposal problem of CFA, but the phytoextraction of Re by both lucerne and erect milkvetch may also bring an economic profit in the future. Copyright © 2018 Elsevier B.V. All rights reserved.

The photosynthetic and stomatal response of Medicago sativa cv. saranac to free-air CO{sub 2} enrichment (F.A.C.E.) and nitrogen

Energy Technology Data Exchange (ETDEWEB)

Bridson, N.P.

1996-08-01

Plots of Medicago sativa cv. saranac were grown in the field at ambient (355 {mu}mol CO{sub 2} mol{sup -1} air) or elevated (600{mu}mol CO{sub 2} mol{sup -1} air) CO{sub 2} concentrations. High (200kg yr{sup -1}) or low (20kg yr{sup -1}) nitrogen levels were applied to two isogeneic lines, one able and one unable to use nitrogen fixing bacteria. Plants were in the second year of field growth. Exposure to elevated CO{sub 2} was via a Free-Air CO{sub 2} Enrichment System (FACE). Elevated CO{sub 2} increased diurnal assimilation by between 12% and 92%. Analysis of A/C{sub i} responses showed that effective nitrogen fertilisation was more important to rubisCO and RuBP activity than elevated CO{sub 2}. No acclimation was consistently observed. Leaves lower down the canopy were found to have lower Vc{sub max} and J{sub max} values, though age may be the cause of the latter effect. FACE conditions have only a small effect on these responses. There was some evidence found for the down-regulation of photosynthesis in the late afternoon. The FACE conditions had no affect on stomatal density but did increase epidermal cell density.

Resistant and susceptible responses in alfalfa (Medicago sativa to bacterial stem blight caused by Pseudomonas syringae pv. syringae.

Directory of Open Access Journals (Sweden)

Lev G Nemchinov

Full Text Available Bacterial stem blight caused by Pseudomonas syringae pv. syringae is a common disease of alfalfa (Medicago sativa L. Little is known about host-pathogen interactions and host defense mechanisms. Here, individual resistant and susceptible plants were selected from cultivars Maverick and ZG9830 and used for transcript profiling at 24 and 72 hours after inoculation (hai with the isolate PssALF3. Bioinformatic analysis revealed a number of differentially expressed genes (DEGs in resistant and susceptible genotypes. Although resistant plants from each cultivar produced a hypersensitive response, transcriptome analyses indicated that they respond differently at the molecular level. The number of DEGs was higher in resistant plants of ZG9830 at 24 hai than in Maverick, suggesting that ZG9830 plants had a more rapid effector triggered immune response. Unique up-regulated genes in resistant ZG9830 plants included genes encoding putative nematode resistance HSPRO2-like proteins, orthologs for the rice Xa21 and soybean Rpg1-b resistance genes, and TIR-containing R genes lacking both NBS and LRR domains. The suite of R genes up-regulated in resistant Maverick plants had an over-representation of R genes in the CC-NBS-LRR family including two genes for atypical CCR domains and a putative ortholog of the Arabidopsis RPM1 gene. Resistance in both cultivars appears to be mediated primarily by WRKY family transcription factors and expression of genes involved in protein phosphorylation, regulation of transcription, defense response including synthesis of isoflavonoids, and oxidation-reduction processes. These results will further the identification of mechanisms involved in resistance to facilitate selection of parent populations and development of commercial varieties.

Alfalfa breeding benefits from genomics of Medicago truncatula

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Žilije Bernadet

2010-01-01

Full Text Available International programs aim at developing knowledge and tools in the model species Medicago truncatula. Genetic resources, DNA sequences, markers, genetic and physical maps are now publicly available. These efforts contribute to improve breeding schemes of crop species such as alfalfa. However, transfer of information from M. truncatula to alfalfa is not straightforward. The article reviews the gain given by the model species to better analyze genetic determinism of breeding traits in alfalfa. It also shows that investments in alfalfa genomics (DNA sequences, SNP development are needed to benefit from the model species.

Fixed-Precision Sequential Sampling Plans for Estimating Alfalfa Caterpillar, Colias lesbia, Egg Density in Alfalfa, Medicago sativa, Fields in Córdoba, Argentina

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Serra, Gerardo V.; Porta, Norma C. La; Avalos, Susana; Mazzuferi, Vilma

2013-01-01

The alfalfa caterpillar, Colias lesbia (Fabricius) (Lepidoptera: Pieridae), is a major pest of alfalfa, Medicago sativa L. (Fabales: Fabaceae), crops in Argentina. Its management is based mainly on chemical control of larvae whenever the larvae exceed the action threshold. To develop and validate fixed-precision sequential sampling plans, an intensive sampling programme for C. lesbia eggs was carried out in two alfalfa plots located in the Province of Córdoba, Argentina, from 1999 to 2002. Using Resampling for Validation of Sampling Plans software, 12 additional independent data sets were used to validate the sequential sampling plan with precision levels of 0.10 and 0.25 (SE/mean), respectively. For a range of mean densities of 0.10 to 8.35 eggs/sample, an average sample size of only 27 and 26 sample units was required to achieve a desired precision level of 0.25 for the sampling plans of Green and Kuno, respectively. As the precision level was increased to 0.10, average sample size increased to 161 and 157 sample units for the sampling plans of Green and Kuno, respectively. We recommend using Green's sequential sampling plan because it is less sensitive to changes in egg density. These sampling plans are a valuable tool for researchers to study population dynamics and to evaluate integrated pest management strategies. PMID:23909840

Geographically structured genetic variation in the Medicago lupulina-Ensifer mutualism.

Science.gov (United States)

Harrison, Tia L; Wood, Corlett W; Heath, Katy D; Stinchcombe, John R

2017-07-01

Gene flow between genetically differentiated populations can maintain variation in species interactions, especially when population structure is congruent between interacting species. However, large-scale empirical comparisons of the population structure of interacting species are rare, particularly in positive interspecific interactions (mutualisms). One agriculturally and ecologically important mutualism is the partnership between legume plants and rhizobia. Through characterizing and comparing the population genomic structure of the legume Medicago lupulina and two rhizobial species (Ensifer medicae and E. meliloti), we explored the spatial scale of population differentiation between interacting partners in their introduced range in North America. We found high proportions of E. meliloti in southeastern populations and high proportions of E. medicae in northwestern populations. Medicago lupulina and the Ensifer genus showed similar patterns of spatial genetic structure (isolation by distance). However, we detected no evidence of isolation by distance or population structure within either species of bacteria. Genome-wide nucleotide diversity within each of the two Ensifer species was low, suggesting limited introduction of strains, founder events, or severe bottlenecks. Our results suggest that there is potential for geographically structured coevolution between M. lupulina and the Ensifer genus, but not between M. lupulina and either Ensifer species. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

Citric acid- and Tween(®) 80-assisted phytoremediation of a co-contaminated soil: alfalfa (Medicago sativa L.) performance and remediation potential.

Science.gov (United States)

Agnello, A C; Huguenot, D; van Hullebusch, E D; Esposito, G

2016-05-01

A pot experiment was designed to assess the phytoremediation potential of alfalfa (Medicago sativa L.) in a co-contaminated (i.e., heavy metals and petroleum hydrocarbons) soil and the influence of citric acid and Tween(®) 80 (polyethylene glycol sorbitan monooleate), applied individually and combined together, for their possible use in chemically assisted phytoremediation. The results showed that alfalfa plants could tolerate and grow in a co-contaminated soil. Over a 90-day experimental time, shoot and root biomass increased and negligible plant mortality occurred. Heavy metals were uptaken by alfalfa to a limited extent, mostly by plant roots, and their concentration in plant tissues were in the following order: Zn > Cu > Pb. Microbial population (alkane-degrading microorganisms) and activity (lipase enzyme) were enhanced in the presence of alfalfa with rhizosphere effects of 9.1 and 1.5, respectively, after 90 days. Soil amendments did not significantly enhance plant metal concentration or total uptake. In contrast, the combination of citric acid and Tween(®) 80 significantly improved alkane-degrading microorganisms (2.4-fold increase) and lipase activity (5.3-fold increase) in the rhizosphere of amended plants, after 30 days of experiment. This evidence supports a favorable response of alfalfa in terms of tolerance to a co-contaminated soil and improvement of rhizosphere microbial number and activity, additionally enhanced by the joint application of citric acid and Tween(®) 80, which could be promising for future phytoremediation applications.

Silicon Priming Created an Enhanced Tolerance in Alfalfa (Medicago sativa L.) Seedlings in Response to High Alkaline Stress.

Science.gov (United States)

Liu, Duo; Liu, Miao; Liu, Xiao-Long; Cheng, Xian-Guo; Liang, Zheng-Wei

2018-01-01

Alkaline stress as a result of higher pH usually triggers more severe physiological damage to plants than that of saline stress with a neutral pH. In the present study, we demonstrated that silicon (Si) priming of alfalfa ( Medicago sativa L.) seedlings increased their tolerance to high alkaline stress situations. Gongnong No. 1 seedlings were subjected to alkaline stress simulated by 25 mM Na 2 CO 3 (pH 11.2). Alkaline stress greatly decreased the biomass and caused severe lodging or wilting of alfalfa seedlings. In contrast, the application of Si to alfalfa seedlings 36 h prior to the alkaline treatment significantly alleviated the damage symptoms and greatly increased the biomass and chlorophyll content. Because of being concomitant with increasing photosynthesis and water use efficiency, decreasing membrane injury and malondialdehyde content, and increasing peroxidase and catalase ascorbate activities in alfalfa leaves, thereby alleviating the triggered oxidative damage by alkaline stress to the plant. Furthermore, Si priming significantly decreased the accumulation of protein and proline content in alfalfa, thus reducing photosynthetic feedback repression. Si priming significantly accumulated more Na in the roots, but led to a decrease of Na accumulation and an increase of K accumulation in the leaves under alkaline stress. Meanwhile, Si priming decreased the accumulation of metal ions such as Mg, Fe, Mn, and Zn in the roots of alfalfa seedlings under alkaline stress. Collectively, these results suggested that Si is involved in the metabolic or physiological changes and has a potent priming effect on the alkaline tolerance of alfalfa seedlings. The present study indicated that Si priming is a new approach to improve the alkaline tolerance in alfalfa and provides increasing information for further exploration of the alkaline stress response at the molecular level in alfalfa.

 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...

Efecto de las arañas (Arachnida: Araneae como depredadoras de insectos plaga en cultivos de alfalfa (Medicago sativa (Fabaceae en Argentina

Directory of Open Access Journals (Sweden)

Andrea Armendano

2011-12-01

Full Text Available Effect of spiders (Arachnida: Araneae as predators of insect pest in alfalfa crops (Medicago sativa (Fabaceae in Argentina. Spiders are predators that reduce insect pest populations in agroecosystems. Trials were conducted to measure the selectivity against different insect preys, the daily consumption, effect of predators alone and together with a known number of preys, and the indirect effect of predators on vegetation. For this, experimental units (1x1m were used covered with a fine plastic mesh. Misumenops pallidus, Oxyopes salticus and Araneus sp. were used as generalist predators, and aphids, weevils, locusts, chrysomelids and Lepidoptera larvae as their potential preys. Among the preys offered, the spiders preferred Lepidoptera larvae compared to the other two pests groups (weevils and aphids. The maximum consumption rate was of 93.33% for Lepidoptera larvae, 25.33% for aphids and 11.67% for weevils. The Q Index values for the three species of spiders showed a positive selectivity only for defoliating larvae. O. salticus showed the highest values of consumption rates while Rachiplusia nu was the most consumed. The maximum value of consumption in 24 hours was showed by O. salticus on R. nu (C=2.8. The association of several species of predatory spiders increased the total number of insects captured, and also showed that the addition of spiders caused a decrease in the number of leaves damaged by the effect of lepidopterous larvae. Rev. Biol. Trop. 59 (4: 1651-1662. Epub 2011 December 01

Arbuscular Mycorrhizal Colonization Alters Subcellular Distribution and Chemical Forms of Cadmium in Medicago sativa L. and Resists Cadmium Toxicity

Science.gov (United States)

Gao, Yanzheng

2012-01-01

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 mg·kg−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. PMID:23139811

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.

A method for the isolation of root hairs from the model legume Medicago truncatula

NARCIS (Netherlands)

Ramos Escribano, J.; Bisseling, T.

2003-01-01

A new method for the isolation of root hairs from the model legume, Medicago truncatula, was developed. The procedure involves the propagation of detached roots on agar plates and the collection of root hairs by immersion in liquid nitrogen. Yields of up to 40 µg of root hair protein were obtained

Absorption of SO/sub 2/ by pecan (Carya illinoensis (Wang) K. Koch) and alfalfa (Medicago sativa L. ) and its effect on net photosynthesis

Energy Technology Data Exchange (ETDEWEB)

Sisson, W.B.; Booth, J.A.; Throneberry, G.O.

1981-06-01

Absorption rates of SO/sub 2/ by pecan (Carya illinoensis (Wang) K. Koch) leaflets exposed to 2.6, 5.2, and 7.8 mg SO/sub 2/ m/sup -3/ were measured over a 2 h period. SO/sub 2/ was rapidly absorbed by the leaflets in all treatments during the initial 30-50 min; the rate of uptake decreased to a rather constant level thereafter. Total SO/sub 2/ absorbed during the 2 h period was 15.6, 25.6, and 38.9 nmol cm/sup -2/ for the low, medium, and high SO/sub 2/ concentrations, respectively. Reductions in net photosynthetic rates were proportional to ambient SO/sub 2/ concentrations and total SO/sub 2/ absorbed. Partial photosynthetic recovery occurred in all treatments during a 2 hr post-treatment period and full recovery occurred during a 12 h dark period. Exposure to SO/sub 2/ resulted in slight increases in stomatal and boundary layer resistances to CO/sub 2/ and substantial increases in residual resistances. Absorption rates of SO/sub 2/ by alfalfa (Medicago sativa L.) exposed to 5.2 mg SO/sub 2/ m/sup -3/ for 1 h were approximately double those of pecan exposed to the same ambient SO/sub 2/ concentration. Alfalfa net photosynthetic rates were reduced 74% after 1 h exposure to 5.2 mg SO/sub 2/ m/sup -3/ while a depression of 42% occurred in pecan.

The Medicago Genome Provides Insight into the Evolution of Rhizobial Symbioses

Science.gov (United States)

Young, Nevin D.; Debellé, Frédéric; Oldroyd, Giles E. D.; Geurts, Rene; Cannon, Steven B.; Udvardi, Michael K.; Benedito, Vagner A.; Mayer, Klaus F. X.; Gouzy, Jérôme; Schoof, Heiko; Van de Peer, Yves; Proost, Sebastian; Cook, Douglas R.; Meyers, Blake C.; Spannagl, Manuel; Cheung, Foo; De Mita, Stéphane; Krishnakumar, Vivek; Gundlach, Heidrun; Zhou, Shiguo; Mudge, Joann; Bharti, Arvind K.; Murray, Jeremy D.; Naoumkina, Marina A.; Rosen, Benjamin; Silverstein, Kevin A. T.; Tang, Haibao; Rombauts, Stephane; Zhao, Patrick X.; Zhou, Peng; Barbe, Valérie; Bardou, Philippe; Bechner, Michael; Bellec, Arnaud; Berger, Anne; Bergès, Hélène; Bidwell, Shelby; Bisseling, Ton; Choisne, Nathalie; Couloux, Arnaud; Denny, Roxanne; Deshpande, Shweta; Dai, Xinbin; Doyle, Jeff; Dudez, Anne-Marie; Farmer, Andrew D.; Fouteau, Stéphanie; Franken, Carolien; Gibelin, Chrystel; Gish, John; Goldstein, Steven; González, Alvaro J.; Green, Pamela J.; Hallab, Asis; Hartog, Marijke; Hua, Axin; Humphray, Sean; Jeong, Dong-Hoon; Jing, Yi; Jöcker, Anika; Kenton, Steve M.; Kim, Dong-Jin; Klee, Kathrin; Lai, Hongshing; Lang, Chunting; Lin, Shaoping; Macmil, Simone L; Magdelenat, Ghislaine; Matthews, Lucy; McCorrison, Jamison; Monaghan, Erin L.; Mun, Jeong-Hwan; Najar, Fares Z.; Nicholson, Christine; Noirot, Céline; O’Bleness, Majesta; Paule, Charles R.; Poulain, Julie; Prion, Florent; Qin, Baifang; Qu, Chunmei; Retzel, Ernest F.; Riddle, Claire; Sallet, Erika; Samain, Sylvie; Samson, Nicolas; Sanders, Iryna; Saurat, Olivier; Scarpelli, Claude; Schiex, Thomas; Segurens, Béatrice; Severin, Andrew J.; Sherrier, D. Janine; Shi, Ruihua; Sims, Sarah; Singer, Susan R.; Sinharoy, Senjuti; Sterck, Lieven; Viollet, Agnès; Wang, Bing-Bing; Wang, Keqin; Wang, Mingyi; Wang, Xiaohong; Warfsmann, Jens; Weissenbach, Jean; White, Doug D.; White, Jim D.; Wiley, Graham B.; Wincker, Patrick; Xing, Yanbo; Yang, Limei; Yao, Ziyun; Ying, Fu; Zhai, Jixian; Zhou, Liping; Zuber, Antoine; Dénarié, Jean; Dixon, Richard A.; May, Gregory D.; Schwartz, David C.; Rogers, Jane; Quétier, Francis; Town, Christopher D.; Roe, Bruce A.

2011-01-01

Legumes (Fabaceae or Leguminosae) are unique among cultivated plants for their ability to carry out endosymbiotic nitrogen fixation with rhizobial bacteria, a process that takes place in a specialized structure known as the nodule. Legumes belong to one of the two main groups of eurosids, the Fabidae, which includes most species capable of endosymbiotic nitrogen fixation 1. Legumes comprise several evolutionary lineages derived from a common ancestor 60 million years ago (Mya). Papilionoids are the largest clade, dating nearly to the origin of legumes and containing most cultivated species 2. Medicago truncatula (Mt) is a long-established model for the study of legume biology. Here we describe the draft sequence of the Mt euchromatin based on a recently completed BAC-assembly supplemented with Illumina-shotgun sequence, together capturing ~94% of all Mt genes. A whole-genome duplication (WGD) approximately 58 Mya played a major role in shaping the Mt genome and thereby contributed to the evolution of endosymbiotic nitrogen fixation. Subsequent to the WGD, the Mt genome experienced higher levels of rearrangement than two other sequenced legumes, Glycine max (Gm) and Lotus japonicus (Lj). Mt is a close relative of alfalfa (M. sativa), a widely cultivated crop with limited genomics tools and complex autotetraploid genetics. As such, the Mt genome sequence provides significant opportunities to expand alfalfa’s genomic toolbox. PMID:22089132

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

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

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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

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

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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.

Tolerancia experimental de las especies vegetales Nicotiana glauca, Jacaranda mimosifolia, Tecoma stans, Medicago sativa y Spinacea oleracea al boro, en Argentina

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Marta L. de Viana

2008-09-01

Full Text Available La actividad de las industrias borateras constituye una fuente puntual y difusa de contaminación del aire, suelo y aguas superficiales y profundas. Por lo tanto, el estudio y experimentación acerca de las posibles formas de contrarrestar este impacto constituye una prioridad. Una técnica relativamente nueva para descontaminar suelos es la fitorremediación, que emplea plantas y microorganismos asociados. El primer paso es detectar las especies vegetales tolerantes, lo que constituye el objetivo de este trabajo. Se realizó un experimento en laboratorio para evaluar la germinación, la supervivencia y el crecimiento de distintas especies en diferentes concentraciones de boro. Al comienzo y al final del experimento se determinó la concentración de boro en el sustrato para cada tratamiento y para sustratos con y sin vegetación. Se encontraron diferencias significativas debidas al tratamiento, la especie y la interacción especie *tratamiento. M. sativa, N. glauca y J. mimosifolia fueron las especies de mayor tolerancia al boro. Las otras especies presentaron una disminución en todas las variables-respuesta en función de la concentración del contaminante. Todas presentaron una baja supervivencia en la máxima concentración. La disminución de boro fue máxima en el tratamiento de 30 ppm de boro con M. sativa y la menor se registró en los tratamiento de 20 ppm de boro con J. mimosifolia y de 30 ppm de boro con T. stans y S. oleraceae. Se concluye que N. glauca, M. sativa y J. mimosifolia podrían considerarse como prometedoras en remediación.Experimental tolerance to boron of the plant species Nicotiana glauca, Jacaranda mimosifolia, Tecoma stans, Medicago sativa y Spinacea oleracea in Argentina. The activity of boron industries is a punctual and diffuse source of air, soil and water pollution. Therefore, it is a priority to study possible ways of reducing this impact. A relatively new technology for reducing soil pollution is

Effects of four short-chain fatty acids or salts on fermentation characteristics and aerobic stability of alfalfa (Medicago sativa L.) silage.

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Yuan, Xian J; Wen, Ai Y; Wang, Jian; Desta, Seare T; Dong, Zhi H; Shao, Tao

2018-01-01

The objective of the present study was to evaluate the effects of four chemicals on the fermentation quality and aerobic stability of alfalfa (Medicago sativa L.) silage. Wilted alfalfa was ensiled without additive (control), or with formic acid (FA), potassium diformate (KDF), sodium diacetate (SDA) or calcium propionate (CAP). After 60 days of ensiling, the pH values in FA, KDF and SDA silages were lower (P < 0.05) compared to that of control and CAP silages, and chemicals (P < 0.05) decreased butyric acid and ammonia N concentrations and populations of aerobic bacteria and yeasts compared to the control. The SDA and CAP silages had a higher (P < 0.05) lactic acid bacteria content compared to the FA and KDF silages. The SDA and CAP silages had higher (P < 0.05) acetic and propionic acid contents compared to the other silages, respectively. The ammonia N concentrations in the FA and KDF silages were lower compared to the other silages during the first 5 days of aerobic exposure, and then increased sharply to 105 and 100 g kg -1 total N, respectively, which was higher (P < 0.05) than that of the SDA and CAP silages on day 9 of aerobic exposure. Yeasts and aerobic bacteria counts in SDA silage slowly increased and remained at lower levels compared to the other silages after 7 days of aerobic exposure. Additives prolonged the aerobic stability duration compared to the control, and the SDA and CAP silages remained stable for more than 216 h, followed by the KDF and FA silages (202 and 196 h, respectively). © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Transgenic alfalfa (Medicago sativa) with increased sucrose phosphate synthase activity shows enhanced growth when grown under N2-fixing conditions.

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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.

Microsatellite diversity and broad scale geographic structure in a model legume: building a set of nested core collection for studying naturally occurring variation in Medicago truncatula

DEFF Research Database (Denmark)

Ronfort, Joelle; Bataillon, Thomas; Santoni, Sylvain

2006-01-01

at representing the genetic diversity of this species with a minimum of repetitiveness. We investigate the patterns of genetic diversity and population structure in a collection of 346 inbred lines representing the breadth of naturally occurring diversity in the Legume plant model Medicago truncatula using 13...... of inbred lines and the core collections are publicly available and will help coordinating efforts for the study of naturally occurring variation in the growing Medicago truncatula community....

Physiological and Proteomic Responses of Contrasting Alfalfa (Medicago sativa L.) Varieties to PEG-Induced Osmotic Stress

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Zhang, Cuimei; Shi, Shangli

2018-01-01

Drought severely limits global plant distribution and agricultural production. Elucidating the physiological and molecular mechanisms governing alfalfa stress responses will contribute to the improvement of drought tolerance in leguminous crops. In this study, the physiological and proteomic responses of two alfalfa (Medicago sativa L.) varieties contrasting in drought tolerance, Longzhong (drought-tolerant) and Gannong No. 3 (drought-sensitive), were comparatively assayed when seedlings were exposed to -1.2 MPa polyethylene glycol (PEG-6000) treatments for 15 days. The results showed that the levels of proline, malondialdehyde (MDA), hydrogen peroxide (H2O2), hydroxyl free radical (OH•) and superoxide anion free radical (O2•-) in both varieties were significantly increased, while the root activity, the superoxide dismutase (SOD) and glutathione reductase (GR) activities, and the ratios of reduced/oxidized ascorbate (AsA/DHA) and reduced/oxidized glutathione (GSH/GSSG) were significantly decreased. The soluble protein and soluble sugar contents, the total antioxidant capability (T-AOC) and the activities of peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) first increased and then decreased with the increase in treatment days. Under osmotic stress, Longzhong exhibited lower levels of MDA, H2O2, OH• and O2•- but higher levels of SOD, CAT, APX, T-AOC and ratios of AsA/DHA and GSH/GSSG compared with Gannong No.3. Using isobaric tags for relative and absolute quantification (iTRAQ), 142 differentially accumulated proteins (DAPs) were identified from two alfalfa varieties, including 52 proteins (34 up-regulated and 18 down-regulated) in Longzhong, 71 proteins (28 up-regulated and 43 down-regulated) in Gannong No. 3, and 19 proteins (13 up-regulated and 6 down-regulated) shared by both varieties. Most of these DAPs were involved in stress and defense, protein metabolism, transmembrane transport, signal transduction, as well as cell wall and

Physiological and Proteomic Responses of Contrasting Alfalfa (Medicago sativa L.) Varieties to PEG-Induced Osmotic Stress.

Science.gov (United States)

Zhang, Cuimei; Shi, Shangli

2018-01-01

Drought severely limits global plant distribution and agricultural production. Elucidating the physiological and molecular mechanisms governing alfalfa stress responses will contribute to the improvement of drought tolerance in leguminous crops. In this study, the physiological and proteomic responses of two alfalfa ( Medicago sativa L.) varieties contrasting in drought tolerance, Longzhong (drought-tolerant) and Gannong No. 3 (drought-sensitive), were comparatively assayed when seedlings were exposed to -1.2 MPa polyethylene glycol (PEG-6000) treatments for 15 days. The results showed that the levels of proline, malondialdehyde (MDA), hydrogen peroxide (H 2 O 2 ), hydroxyl free radical (OH • ) and superoxide anion free radical (O 2 •- ) in both varieties were significantly increased, while the root activity, the superoxide dismutase (SOD) and glutathione reductase (GR) activities, and the ratios of reduced/oxidized ascorbate (AsA/DHA) and reduced/oxidized glutathione (GSH/GSSG) were significantly decreased. The soluble protein and soluble sugar contents, the total antioxidant capability (T-AOC) and the activities of peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) first increased and then decreased with the increase in treatment days. Under osmotic stress, Longzhong exhibited lower levels of MDA, H 2 O 2 , OH • and O 2 •- but higher levels of SOD, CAT, APX, T-AOC and ratios of AsA/DHA and GSH/GSSG compared with Gannong No.3. Using isobaric tags for relative and absolute quantification (iTRAQ), 142 differentially accumulated proteins (DAPs) were identified from two alfalfa varieties, including 52 proteins (34 up-regulated and 18 down-regulated) in Longzhong, 71 proteins (28 up-regulated and 43 down-regulated) in Gannong No. 3, and 19 proteins (13 up-regulated and 6 down-regulated) shared by both varieties. Most of these DAPs were involved in stress and defense, protein metabolism, transmembrane transport, signal transduction, as well as cell

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

Non-enzymatic access to the plasma membrane of Medicago root hairs by laser microsurgery

Energy Technology Data Exchange (ETDEWEB)

Kurkdjian, A.; Leitz, G.; Manigault, P.; Harim, A.; Greulich, K. O.

1993-07-01

Using UV laser microsurgery, the cell walls of root hairs from Medicago sativa (alfalfa) were perforated under plasmolysing conditions, giving direct access to the plasma membrane without enzyme treatment. The opening in the cell wall of a few μm in diameter results in immediate movement of the protoplasm and partial or complete extrusion of the cell contents. The movement of the protoplasm is retarded by increases in calcium concentration. The calcium-dependency of the movement of the protoplasm allows us to obtain preferentially the extrusion of protoplasm, or to gain access to a small area of plasma membrane in situ. The complete protoplasm can be expelled, to form a protoplast. Fluorescein diacetate staining indicated esterase activity and membrane integrity of the protoplasts. Microscopic examination revealed organelle movement and the presence of a nucleus. The plasma membrane was free from cell wall fragments, as shown by Tinopal staining. Conditions for obtaining plasmolysis without disturbing the physiology of the root hairs too much were achieved by slow, stepwise and reversible plasmolysis. Cytoplasmic streaming in root hairs was maintained during plasmolysis and laser microperforation. This laser technique should be suitable for the performance of electrophysiological studies using the patch-clamp technique on plasma membrane from non-enzyme-treated cells. (author)

Non-enzymatic access to the plasma membrane of Medicago root hairs by laser microsurgery

International Nuclear Information System (INIS)

Kurkdjian, A.; Leitz, G.; Manigault, P.; Harim, A.; Greulich, K.O.

1993-01-01

Using UV laser microsurgery, the cell walls of root hairs from Medicago sativa (alfalfa) were perforated under plasmolysing conditions, giving direct access to the plasma membrane without enzyme treatment. The opening in the cell wall of a few μm in diameter results in immediate movement of the protoplasm and partial or complete extrusion of the cell contents. The movement of the protoplasm is retarded by increases in calcium concentration. The calcium-dependency of the movement of the protoplasm allows us to obtain preferentially the extrusion of protoplasm, or to gain access to a small area of plasma membrane in situ. The complete protoplasm can be expelled, to form a protoplast. Fluorescein diacetate staining indicated esterase activity and membrane integrity of the protoplasts. Microscopic examination revealed organelle movement and the presence of a nucleus. The plasma membrane was free from cell wall fragments, as shown by Tinopal staining. Conditions for obtaining plasmolysis without disturbing the physiology of the root hairs too much were achieved by slow, stepwise and reversible plasmolysis. Cytoplasmic streaming in root hairs was maintained during plasmolysis and laser microperforation. This laser technique should be suitable for the performance of electrophysiological studies using the patch-clamp technique on plasma membrane from non-enzyme-treated cells. (author)

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...

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...

De novo characterization of fall dormant and nondormant alfalfa (Medicago sativa L.) leaf transcriptome and identification of candidate genes related to fall dormancy.

Science.gov (United States)

Zhang, Senhao; Shi, Yinghua; Cheng, Ningning; Du, Hongqi; Fan, Wenna; Wang, Chengzhang

2015-01-01

Alfalfa (Medicago sativa L.) is one of the most widely cultivated perennial forage legumes worldwide. Fall dormancy is an adaptive character related to the biomass production and winter survival in alfalfa. The physiological, biochemical and molecular mechanisms causing fall dormancy and the related genes have not been well studied. In this study, we sequenced two standard varieties of alfalfa (dormant and non-dormant) at two time points and generated approximately 160 million high quality paired-end sequence reads using sequencing by synthesis (SBS) technology. The de novo transcriptome assembly generated a set of 192,875 transcripts with an average length of 856 bp representing about 165.1 Mb of the alfalfa leaf transcriptome. After assembly, 111,062 (57.6%) transcripts were annotated against the NCBI non-redundant database. A total of 30,165 (15.6%) transcripts were mapped to 323 Kyoto Encyclopedia of Genes and Genomes pathways. We also identified 41,973 simple sequence repeats, which can be used to generate markers for alfalfa, and 1,541 transcription factors were identified across 1,350 transcripts. Gene expression between dormant and non-dormant alfalfa at different time points were performed, and we identified several differentially expressed genes potentially related to fall dormancy. The Gene Ontology and pathways information were also identified. We sequenced and assembled the leaf transcriptome of alfalfa related to fall dormancy, and also identified some genes of interest involved in the fall dormancy mechanism. Thus, our research focused on studying fall dormancy in alfalfa through transcriptome sequencing. The sequencing and gene expression data generated in this study may be used further to elucidate the complete mechanisms governing fall dormancy in alfalfa.

Co-transforming bar and CsALDH Genes Enhanced Resistance to Herbicide and Drought and Salt Stress in Transgenic Alfalfa (Medicago sativa L.)

Science.gov (United States)

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 diagnosis using PCR. Real-time PCR analysis indicated that drought and salt stress induced high CsALDH expression in the leaves of the transgenic plants. The CsALDH expression levels under drought (15 d) and salt stress (200 mM NaCl) were 6.11 and 6.87 times higher than in the control plants, respectively. In comparison to the WT plants, no abnormal phenotypes were observed among the transgenic plants, which showed significant enhancement of tolerance to 15 d of drought and 10 d of salinity treatment. Evaluation of the physiological and biochemical indices during drought and salt stress of the transgenic plants revealed relatively lower Na+ content and higher K+ content in the leaves relative to the WT plants, a reduction of toxic on effects and maintenance of osmotic adjustment. In addition, the transgenic plants could maintain a higher relative water content level, higher shoot biomass, fewer changes in the photosystem, decreased membrane injury, and a lower level of osmotic stress. These results indicate that the co-expression of the introduced bar and CsALDH genes enhanced the herbicide, drought and salt tolerance of alfalfa and therefore can potentially be used as a novel genetic resource for the future breeding programs to develop new cultivars. PMID:26734025

Impacts of coal fly ash on plant growth and accumulation of essential nutrients and trace elements by alfalfa (Medicago sativa) grown in a loessial soil.

Science.gov (United States)

He, Honghua; Dong, Zhigang; Peng, Qi; Wang, Xia; Fan, Chenbin; Zhang, Xingchang

2017-07-15

Coal fly ash (CFA) is a problematic solid waste all over the world. One distinct beneficial reuse of CFA is its utilization in land application as a soil amendment. A pot experiment was carried out to assess the feasibility of using CFA to improve plant growth and increase the supply of plant-essential elements and selenium (Se) of a loessial soil for agricultural purpose. Plants of alfalfa (Medicago sativa) were grown in a loessial soil amended with different rates (5%, 10%, 20% and 40%) of CFA for two years and subjected to four successive cuttings. Dry mass of shoots and roots, concentrations of plant-essential elements and Se in plants were measured. Shoot dry mass and root dry mass were always significantly increased by 5%, 10% and 20% CFA treatments, and by 40% CFA treatment in all harvests except the first one. The CFA had a higher supply of exchangeable phosphorus (P), magnesium (Mg), copper (Cu), zinc (Zn), molybdenum (Mo), and Se than the loessial soil. Shoot P, calcium (Ca), Mg, Mo, boron (B), and Se concentrations were generally markedly increased, but shoot potassium (K), Cu, and Zn concentrations were generally reduced. The CFA can be a promising source of some essential elements and Se for plants grown in the loessial soil, and an application rate of not higher than 5% should be safe for agricultural purpose without causing plant toxicity symptoms in the studied loessial soil and similar soils. Field trials will be carried out to confirm the results of the pot experiment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Quantification of the Volume and Surface Area of Symbiosomes and Vacuoles of Infected Cells in Root Nodules of Medicago truncatula

NARCIS (Netherlands)

Gavrin, A.Y.; Fedorova, E.

2015-01-01

Legumes are able to form endosymbiotic interactions with nitrogen-fixing rhizobia. Endosymbiosis takes shape in formation of a symbiotic organ, the root nodule. Medicago truncatula (M. truncatula) nodules contain several zones representing subsequent stages of development. The apical part of the

Genetic analysis of tolerance to boron toxicity in the legume Medicago truncatula.

Science.gov (United States)

Bogacki, Paul; Peck, David M; Nair, Ramakrishnan M; Howie, Jake; Oldach, Klaus H

2013-03-27

Medicago truncatula Gaertn. (barrel medic) is cultivated as a pasture legume for its high protein content and ability to improve soils through nitrogen fixation. Toxic concentrations of the micronutrient Boron (B) in agricultural soils hamper the production of cereal and leguminous crops. In cereals, the genetic analysis of B tolerance has led to the development of molecular selection tools to introgress and maintain the B tolerance trait in breeding lines. There is a comparable need for selection tools in legumes that grow on these toxic soils, often in rotation with cereals. Genetic variation for B tolerance in Medicago truncatula was utilised to generate two F2 populations from crosses between tolerant and intolerant parents. Phenotyping under B stress revealed a close correlation between B tolerance and biomass production and a segregation ratio explained by a single dominant locus. M. truncatula homologues of the Arabidopsis major intrinsic protein (MIP) gene AtNIP5;1 and the efflux-type transporter gene AtBOR1, both known for B transport, were identified and nearby molecular markers screened across F2 lines to verify linkage with the B-tolerant phenotype. Most (95%) of the phenotypic variation could be explained by the SSR markers h2_6e22a and h2_21b19a, which flank a cluster of five predicted MIP genes on chromosome 4. Three CAPS markers (MtBtol-1,-2,-3) were developed to dissect the region further. Expression analysis of the five predicted MIPs indicated that only MtNIP3 was expressed when leaf tissue and roots were assessed. MtNIP3 showed low and equal expression in the roots of tolerant and intolerant lines but a 4-fold higher expression level in the leaves of B-tolerant cultivars. The expression profile correlates closely with the B concentration measured in the leaves and roots of tolerant and intolerant plants. Whereas no significant difference in B concentration exists between roots of tolerant and intolerant plants, the B concentration in the leaves

Medicago truncatula copper transporter 1 (MtCOPT1) delivers copper for symbiotic nitrogen fixation.

Science.gov (United States)

Senovilla, Marta; Castro-Rodríguez, Rosario; Abreu, Isidro; Escudero, Viviana; Kryvoruchko, Igor; Udvardi, Michael K; Imperial, Juan; González-Guerrero, Manuel

2018-04-01

Copper is an essential nutrient for symbiotic nitrogen fixation. This element is delivered by the host plant to the nodule, where membrane copper (Cu) transporter would introduce it into the cell to synthesize cupro-proteins. COPT family members in the model legume Medicago truncatula were identified and their expression determined. Yeast complementation assays, confocal microscopy and phenotypical characterization of a Tnt1 insertional mutant line were carried out in the nodule-specific M. truncatula COPT family member. Medicago truncatula genome encodes eight COPT transporters. MtCOPT1 (Medtr4g019870) is the only nodule-specific COPT gene. It is located in the plasma membrane of the differentiation, interzone and early fixation zones. Loss of MtCOPT1 function results in a Cu-mitigated reduction of biomass production when the plant obtains its nitrogen exclusively from symbiotic nitrogen fixation. Mutation of MtCOPT1 results in diminished nitrogenase activity in nodules, likely an indirect effect from the loss of a Cu-dependent function, such as cytochrome oxidase activity in copt1-1 bacteroids. These data are consistent with a model in which MtCOPT1 transports Cu from the apoplast into nodule cells to provide Cu for essential metabolic processes associated with symbiotic nitrogen fixation. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

Arbuscular mycorrhizal (Funneliformis mosseae improves alfalfa (Medicago sativa L. re-growth ability in saline soil through enhanced nitrogen remobilization and improved nutritional balance

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Amin Namdari

2018-03-01

Full Text Available In current study, the influence of arbuscular mycorrhizal fungi (AMF on salinity tolerance in terms of root’s reserves remobilization to shoot and its relationship with re-growth ability and ionic status of alfalfa (Medicago sativa L. plants were investigated. In a pot experiment, a factorial experiment in base of randomized complete blocks design in three replications was carried out. Alfalfa plants (Iranian cultivar-Baghdadi inoculated with AMF (Funneliformis mosseae or retained as un-inoculated, were grown in soil and irrigated with three salt concentrations including 1.4 (control, 7 and 12 dS/m. Three harvests were carried out at 10% of flowering stage. AMF inoculation increased the size of root sugars and soluble N pools at harvest time. The shoot biomass production following harvest had a close correlation with nitrogen (N remobilization from root (r=0.92, P≤0.01. However salinity stress significantly reduced amount and percentage of N remobilization to re-growing shoot but AMF plants exhibited greater amount and percentage of root N pools dedicated to remobilization. AMF inoculation also affected ionic relations of plants as AM+ plants contained greater K+ within both root and shoot organs while Ca2+ and Na+ were affected by AMF only within shoot tissue. AMF plants exhibited higher K+/Na+ within shoot and Ca+2/Na+ within root organs. There was a high positive correlation coefficient between K+/Na+, Ca+2/Na+ ratios and N remobilization from root (respectively, r=0.92, 0.88; P≤0.01. To sum up, ionic status within both root and shoot organs, got more balanced by AMF inoculation so that AMF reduced limitations within both source (root and sink (re-growing shoot organs concerning N remobilization to re-growing shoot.

The molecular genetic linkage map of the model legume Medicago truncatula: an essential tool for comparative legume genomics and the isolation of agronomically important genes

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Ané Jean-Michel

2002-01-01

Full Text Available Abstract Background The legume Medicago truncatula has emerged as a model plant for the molecular and genetic dissection of various plant processes involved in rhizobial, mycorrhizal and pathogenic plant-microbe interactions. Aiming to develop essential tools for such genetic approaches, we have established the first genetic map of this species. Two parental homozygous lines were selected from the cultivar Jemalong and from the Algerian natural population (DZA315 on the basis of their molecular and phenotypic polymorphism. Results An F2 segregating population of 124 individuals between these two lines was obtained using an efficient manual crossing technique established for M. truncatula and was used to construct a genetic map. This map spans 1225 cM (average 470 kb/cM and comprises 289 markers including RAPD, AFLP, known genes and isoenzymes arranged in 8 linkage groups (2n = 16. Markers are uniformly distributed throughout the map and segregation distortion is limited to only 3 linkage groups. By mapping a number of common markers, the eight linkage groups are shown to be homologous to those of diploid alfalfa (M. sativa, implying a good level of macrosynteny between the two genomes. Using this M. truncatula map and the derived F3 populations, we were able to map the Mtsym6 symbiotic gene on linkage group 8 and the SPC gene, responsible for the direction of pod coiling, on linkage group 7. Conclusions These results demonstrate that Medicago truncatula is amenable to diploid genetic analysis and they open the way to map-based cloning of symbiotic or other agronomically-important genes using this model plant.

Cloning and expression of 1-aminocyclopropane-1-carboxylate oxidase cDNA induced by thidiazuron during somatic embryogenesis of alfalfa (Medicago sativa).

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Feng, Bi-Hong; Wu, Bei; Zhang, Chun-Rong; Huang, Xia; Chen, Yun-Feng; Huang, Xue-Lin

2012-01-15

Embryogenic callus (EC) induced from petioles of alfalfa (Medicago sativa L. cv. Jinnan) on B5h medium turned green, compact and non-embryogenic when the kinetin (KN) in the medium was replaced partially or completely by thidiazuron (TDZ). The application of CoCl₂, which is an inhibitor of 1-aminocyclopropane-1-carboxylate oxidase (ACO), counteracted the effect of TDZ. Ethylene has been shown to be involved in the modulation of TDZ-induced morphogenesis responses. However, very little is known about the genes involved in ethylene formation during somatic embryogenesis (SE). To investigate whether ethylene mediated by ACO is involved in the effect of TDZ on inhibition of embryogenic competence of the alfalfa callus. In this study we cloned full-length ACO cDNA from the alfalfa callus, named MsACO, and observed changes in this gene expression during callus formation and induction of SE under treatment with TDZ or TDZ plus CoCl₂. RNA blot analysis showed that during the EC subcultural period, the expression level of MsACO in EC was significantly increased on the 2nd day, rose to the highest level on the 8th day and remained at this high level until the 21st day. However, the ACO expression in the TDZ (0.93 μM)-treated callus was higher than in the EC especially on the 8th day. Moreover the ACO expression level increased with increasing TDZ concentration during the subcultural/maintenance period of the callus. It is worth noting that comparing the treatment with TDZ alone, the treatment with 0.93 μM TDZ plus 50 μM CoCl₂ reduced both of the ACO gene expressions and ACO activity in the treated callus. These results indicate that the effect of TDZ could be counteracted by CoCl₂ either on the ACO gene expression level or ACO activity. Thus, a TDZ inhibitory effect on embryogenic competence of alfalfa callus could be mediated by ACO gene expression. Crown Copyright © 2011. Published by Elsevier GmbH. All rights reserved.

Fermentation characteristics and nutritive value of low moisture silage made from mature bermudagrass (C. dactylon) and switchgrass (P. virgatum) in mixture with alfalfa (M. sativa) or treated with urea and plantain (Musa AAB

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Two experiments were 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) silage...

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

Interaction of Medicago truncatula Lysin Motif Receptor-Like Kinases, NFP and LYK3, Produced in Nicotiana benthamiana Induces Defence-Like Responses

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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

Effects of Fe-chelate and iron oxide nanoparticles on some of the physiological characteristics of alfalfa (Medicago sativa L.

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Mehri Askary

2018-06-01

Full Text Available Introduction Iron is an essential micronutrient for plant growth that plays an important role in plant metabolism. Iron deficiency is an abiotic stress that is often found in plants grown in calcareous and alkaline soils. The solubility of Fe+3 decreases dramatically with increasing pH. 30% of the arable land worldwide consists of calcareous and alkaline soils. Common iron fertilizers used to reduce deficiency syndromes contain iron(II sulfate heptahydrate (FeSO4.7H2O or iron chelates. Iron chelate (for example Fe-EDTA is absorbed by plants, which however depends on soil conditions especially soil pH. Nowadays , nano-Fe fertilizer can be used as a rich source of iron for plants ,because it gradually releases Fe in a wide pH range (pH 3– 11. Nanofertilizer usage leads to increase element efficiency, reduce soil toxicity and negative effects caused by the excessive consumption of chemical fertilizers and reduce the fertilizer’ s application . This research was carried out to determine the suitable type of iron fertilizer and to evaluate the effects of different concentrations of nano-Fe fertilizer on Medicago sativa Materials and methods In order to investigate the effects of Fe-deficiency and different levels of Fe2O3 nanoparticles compared to Fe-EDTA on leaf growth, photosynthetic pigments and antioxidative activity of alfalfa (Medicago sativa cv.Hamadani, an experiment was conducted based on completely randomized design with three replications in Arak University during 2015. After germination of sterilized seeds of alfalfa, 1-day seedlings were cultured in plastic vases contains perlite. Plants were maintained under 25/18°C day/night temperatures with 12-hr photoperiod. Irrigation was done weekly with 100ml complete Hoagland solution (containing iron chelate (Fe-EDTA for control plants or 100ml Hoagland solution without iron chelate and containing different concentrations of ironoxide nanoparticles (0, 5, 10, 20 and 25µM. Plants

Microsynteny between the Medicago truncatula SYM2-orthologous genomic region and another region located on the same chromosome arm

NARCIS (Netherlands)

Gualtieri, G.; Bisseling, T.

2002-01-01

A synteny based positional cloning approach was started to clone the pea SYM2 gene by using locally conserved genome structure with the model plant Medicago truncatula. We reported that a pea marker tightly linked to SYM2 was used to screen a M. truncatula BAC library, and two contigs named C1/C2

Medicago Scutellata Seed Dormancy Breaking by Ultrasonic Waves

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Nazari Meisam

2014-12-01

Full Text Available In this study dormancy breaking of a hard-coated plant seed, Medicago scutellata, was investigated. The ultrasonic waves effect on the seed germination percentage, germination rate, radicle length and stalk length growth was assessed. Six treatments of waves exposure periods including 0, 1, 3, 5, 7, and 9 minutes were tested under laboratorial conditions. Statistical analyses were done at probability level of 0.01. Results revealed that the ultrasonic waves have a significantly positive effect on the seed dormancy breaking, but there was no linear correlation between the increasing times of exposure with any of the growth features. The best treatment for germination percentage and germination rate was the 7-minute one and the 3-minute one was the best for radicle length growth. Treatments of 3, 5 and 7 minutes had the same effect on stalk length growth and were better than all other treatments. The 9-minute treatment had a negative effect, even lessening the growth of all of the assessed features in comparison with the control treatment.

Local and distal effects of arbuscular mycorrhizal colonization on direct pathway Pi uptake and root growth in Medicago truncatula

DEFF Research Database (Denmark)

Watts-Williams, Stephanie J.; Jakobsen, Iver; Cavagnaro, Timothy R.

2015-01-01

and root growth, at different soil P levels. Medicago truncatula was grown at three soil P levels in split-pots with or without AM fungal inoculation and where one root half grew into soil labelled with 33P. Plant genotypes included the A17 wild type and the mtpt4 mutant. The mtpt4 mutant, colonized by AM...

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

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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/.

Arbuscular mycorrhizal fungi decrease radiocesium accumulation in Medicago truncatula

International Nuclear Information System (INIS)

Gyuricza, Veronika; Declerck, Stephane; Dupre de Boulois, Herve

2010-01-01

The role of arbuscular mycorrhizal fungi (AMF) in plant radiocesium uptake and accumulation remains ambiguous. This is probably due to the presence of other soil microorganisms, the variability of soil characteristics and plant nutritional status or the availability of its chemical analogue, potassium (K). Here, we used an in vitro culture system to study the impact of increased concentration of K on radiocesium accumulation in non K-starved mycorrhizal and non-mycorrhizal Medicago truncatula plants. In the presence of AMF radiocesium uptake decreased regardless of the concentration of K, and its translocation from root to shoot was also significantly lower. Potassium also reduced the accumulation of radiocesium in plants but to a lesser extent than mycorrhization, and without any effect on translocation. These results suggest that AMF in combination with K can play a key role in reducing radiocesium uptake and its subsequent translocation to plant shoots, thereby representing good potential for improved phytomanagement of contaminated areas.

Arbuscular mycorrhizal fungi decrease radiocesium accumulation in Medicago truncatula

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Gyuricza, Veronika; Declerck, Stephane [Universite catholique de Louvain, Earth and Life Institute (ELI), Laboratoire de Mycologie, Croix du Sud 3, 1348 Louvain-la-Neuve (Belgium); Dupre de Boulois, Herve, E-mail: herve.dupre@uclouvain.b [Universite catholique de Louvain, Earth and Life Institute (ELI), Laboratoire de Mycologie, Croix du Sud 3, 1348 Louvain-la-Neuve (Belgium)

2010-08-15

The role of arbuscular mycorrhizal fungi (AMF) in plant radiocesium uptake and accumulation remains ambiguous. This is probably due to the presence of other soil microorganisms, the variability of soil characteristics and plant nutritional status or the availability of its chemical analogue, potassium (K). Here, we used an in vitro culture system to study the impact of increased concentration of K on radiocesium accumulation in non K-starved mycorrhizal and non-mycorrhizal Medicago truncatula plants. In the presence of AMF radiocesium uptake decreased regardless of the concentration of K, and its translocation from root to shoot was also significantly lower. Potassium also reduced the accumulation of radiocesium in plants but to a lesser extent than mycorrhization, and without any effect on translocation. These results suggest that AMF in combination with K can play a key role in reducing radiocesium uptake and its subsequent translocation to plant shoots, thereby representing good potential for improved phytomanagement of contaminated areas.

EFICIENCIA DEL AGUA DE RIEGO EN LA PRODUCCIÓN DE MAÍZ FORRAJERO (Zea mays L. Y ALFALFA (Medicago sativa: IMPACTO SOCIAL Y ECONÓMICO

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Aurelio Pedroza Sandoval

2014-07-01

Full Text Available El maíz y la alfalfa, son los dos principales cultivos forrajeros en la Cuenca Lechera de la Laguna de los estados de Coahuila y Durango, México, donde el recurso hídrico es el mayor factor limitante. El objetivo de este estudio fue hacer una evaluación de la eficiencia biológica, económica y social del uso de agua de riego en los cultivos de maíz forrajero (Zea mays L. y alfalfa (Medicago sativa, mediante un análisis económico comparativo y de eficiencia de productividad. El maíz fue más eficiente que la alfalfa, puesto que un m3 de agua subterránea produjo 5.72 kg de biomasa, $0.67 de ganancia por m3 de agua usada y 100 000 m3 de agua produjeron 0.65 empleos durante el ciclo del cultivo; mientras que la alfalfa produjo 0.215 kg de biomasa, $0.90 de ganancia y se generaron 0.43 empleos con los mismos volúmenes de agua indicados en el maíz. El cultivo de maíz forrajero fue más eficiente en producción de biomasa por volumen de agua utilizado y empleos generados, pero menos eficiente en ganancias, donde la alfalfa fue mejor. Una combinación durante el año de cultivos forrajeros con calidad energética y proteica como el maíz y la alfalfa respectivamente, éstos producidos bajo un programa de rotación, habrán de redundar en un equilibrio entre calidad de forraje, productividad del mismo, un mayor beneficio social y un menor impacto ambiental.

Mycorrhiza Symbiosis Increases the Surface for Sunlight Capture in Medicago truncatula for Better Photosynthetic Production

Science.gov (United States)

Adolfsson, Lisa; 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 Pi 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 Pi fertilization, and also assessed the relationship between levels of AM colonization and these effects. We found that increased Pi supply by either mycorrhization or fertilization led to improved shoot growth associated with increased nitrogen uptake and carbon assimilation. Both mycorrhized and Pi-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 Pi fertilization. Photosynthetic activity per leaf area remained the same regardless of type of treatment. In conclusion, the increase in growth of mycorrhized and Pi-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. PMID:25615871

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

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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.

Genotype, explant, medium, light and radiation effects on the in vitro plant regeneration in alfalfa (Medicago Sativa L.)

International Nuclear Information System (INIS)

El-Fiki, A.A.; Abdel-Hameed, A.A.M.; Sayed, A.I.H.

2005-01-01

The relative importance of genotype, explants, radiation, medium and light and their interactions for in vitro plant regeneration via somatic embryogenesis in alfalfa (Medicago sativa L.) has been studied. Shoot and leaf explants of two commercially grown Egyptian cultivars, Al-Wadi Al-Gadid and Siwa Tarkibi, were used in the study. The effect of gamma radiation doses 40, 80, 120 and 160 Gy were negative on plant regeneration, in spite of increase with some treatments. The best results of plant regeneration were obtained with dose 40 Gy with control light regime (16 h) on MS + 0.5 mg NAA + 1.5 mg BAP in both shoot and leaf explants of cv. Al-Wadi. The shoot explant of cv. Siwa was sensitive for gamma radiation dose 40 Gy while affirmative effect was obtained in leaf explant on MS + 1.0 mg NAA + 0.5 mg BAP with control light regime. However, dose 80 Gy showed the best results on MS + 0.5 mg NAA + 0.5 mg BAP in shoot and leaf explants of both cultivars, with control light regime in shoot explant and dark/light (DL) and dark/dark (DD) in leaf explant of cv. Al-Wadi, while with light/dark (LD) in shoot explant and control light regime in leaf explant of cv. Siwa. On the other hand, the highest plant regeneration ratio observed with dose 120 Gy were on 1.5 mg NAA + 0.5 mg BAP with control light regime in shoot and leaf explants of cv. Al-Wadi but on 0.5 mg NAA + 0.5 mg BAP with control and dark/light (DL) light regime in shoot and leaf explants of cv. Siwa. Whereas, the radiation dose 160 Gy showed severe effect on plant regeneration in both cultivars but highest percentage was observed on MS + 0.5 mg NAA + 0.5 mg BAP with dark/light (DL) in shoot explant, MS + 0.5 mg NAA + 1.5 mg BAP with control light regime in leaf explant of cv. Al-Wadi, MS + 0.5 mg NAA + 1.5 mg BAP in shoot explant and MS + 0.5 mg NAA + 0.5 mg BAP in leaf explant with dark/light (DL) in cv. Siwa. However, the effects of the same doses on callus growth showed that the highest callus weight was

Transgene silencing of sucrose synthase in alfalfa (Medicago sativa L.) stem vascular tissue suggests a role for invertase in cell wall cellulose synthesis.

Science.gov (United States)

Samac, Deborah A; Bucciarelli, Bruna; Miller, Susan S; Yang, S Samuel; O'Rourke, Jamie A; Shin, Sanghyun; Vance, Carroll P

2015-12-01

Alfalfa (Medicago sativa L.) is a widely adapted perennial forage crop that has high biomass production potential. Enhanced cellulose content in alfalfa stems would increase the value of the crop as a bioenergy feedstock. We examined if increased expression of sucrose synthase (SUS; EC 2.4.1.13) would increase cellulose in stem cell walls. Alfalfa plants were transformed with a truncated alfalfa phosphoenolpyruvate carboxylase gene promoter (PEPC7-P4) fused to an alfalfa nodule-enhanced SUS cDNA (MsSUS1) or the β-glucuronidase (GUS) gene. Strong GUS expression was detected in xylem and phloem indicating that the PEPC7-P4 promoter was active in stem vascular tissue. In contrast to expectations, MsSUS1 transcript accumulation was reduced 75-90 % in alfalfa plants containing the PEPC7-P4::MsSUS1 transgene compared to controls. Enzyme assays indicated that SUS activity in stems of selected down-regulated transformants was reduced by greater than 95 % compared to the controls. Although SUS activity was detected in xylem and phloem of control plants by in situ enzyme assays, plants with the PEPC7-P4::MsSUS1 transgene lacked detectable SUS activity in post-elongation stem (PES) internodes and had very low SUS activity in elongating stem (ES) internodes. Loss of SUS protein in PES internodes of down-regulated lines was confirmed by immunoblots. Down-regulation of SUS expression and activity in stem tissue resulted in no obvious phenotype or significant change in cell wall sugar composition. However, alkaline/neutral (A/N) invertase activity increased in SUS down-regulated lines and high levels of acid invertase activity were observed. In situ enzyme assays of stem tissue showed localization of neutral invertase in vascular tissues of ES and PES internodes. These results suggest that invertases play a primary role in providing glucose for cellulose biosynthesis or compensate for the loss of SUS1 activity in stem vascular tissue.

Effects of sowing methods and potassium application on the performance of two Alfalfa cultivars (Medicago sativa L.)

International Nuclear Information System (INIS)

Elhag, B.B.M.

2007-03-01

A field experiment was conducted at the Demonstration Farm of the Faculty of Agriculture, Islamic University of Omdurman during the period from december 2004 to may 2006 to evaluate the effects of three sowing methods (sowing on flat, ridges and mustaba) and the tow levels of potassium fertilizer, (0 k 0 and 50 kg/ha k 1 ) on the performance of alfalfa (Medicago sativa L.). This was carried out using tow cultivars, Hegazi (local) and Alfanafa (introduced). A randomized complete block design with four applications in factorial experiment was used to layout the work field. Sowing was done in the last week of december 2004 at a seed rate of 20 kg/ha by broadcasting the seeds on flat, ridge and mustaba. The first irrigation was applied immediately and the second was done five days after sowing. Subsequent irrigations were performed at an interval of seven days between irrigations during summer and ten days during winter, depending on the weather conditions. A seedling emergence was observed 3 to 5 days after sowing. Weeding was done manually when necessary. The first cut was done 70 days after sowing, when 50% of the plants were in the bloom stage, and the subsequent ones were done monthly, using a sickle, just a above the soil surface. A After the last cut (in Feb 2006), when environmental conditions were favorable, the plants were left were for seed yield which was harvested in April, 2006. Data were collected on plant height, plant population, leaf area index, leaf to stem ratio, fresh weight, dry weight, potassium content in plant, seed-yield and its components. The results revealed that there were significant differences between cultivars, sowing methods, potassium application and all possible interactions between the different treatments for all parameters except number of pods/raceme and total seed-weight in all treatments, leaf to stem ratio, leaf area index, number of racemes/plant, number of seeds/pod and 1000-seed weight in sowing methods and potassium

Inoculação microbiana da silagem de alfafa (Medicago sativa e seu efeito sobre o consumo de matéria seca e sobre a fermentação ruminal em bovinos - DOI: 10.4025/actascianimsci.v25i2.2074 Microbial inoculation of alfalfa silage (Medicago sativa and its effect on dry matter intake and ruminal fermentation in bovines - DOI: 10.4025/actascianimsci.v25i2.2074

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Paulo Henrique Mazza Rodrigues

2003-04-01

Full Text Available O objetivo do presente estudo foi avaliar os efeitos da inoculação microbiana da alfafa (Medicago sativa para ensilagem sobre o consumo de matéria seca, fermentação ruminal e taxa de passagem de líquidos em bovinos. Doze vacas não-gestantes e não-lactantes foram distribuídas em um delineamento em blocos, e os tratamentos corresponderam à silagem pré-secada de alfafa (60% de MS e 19,5% de PB controle ou inoculada com o produto Silobac® (Lactobacillus plantarum e Pediococcus pentosaceus. A dieta experimental continha 50% de silagem de alfafa e 50% de concentrado. O experimento teve duração total de 21 dias, sendo o 21º dia utilizado para colheitas de líquido ruminal realizadas às 0h, 2h, 4h, 6h, 8h, 10h e 12h, após a 1a refeição. A inoculação microbiana da silagem de alfafa não alterou o consumo de MS (inoculada = 2,56 vs. controle = 2,39% PV, o pH do líquido ruminal (6,15 vs. 6,27, a concentração ruminal de N-NH3 (19,0 vs. 18,2mg/dl, a concentração total de AGVs (122,5 vs. 113,8mM ou a proporção molar de ácido acético (66,1 vs. 66,8% molar, propiônico (21,1 vs. 19,6% molar e butírico (12,8 vs. 13,6% molar. Parâmetros relativos à dinâmica líquida ruminal, como o volume líquido (59,5 vs. 63,4 litros e a taxa de passagem de líquidos (8,6 vs. 8,0%/h, também não foram alterados com a inoculação.The objective of this study was to evaluate the effects of microbial inoculation of alfalfa (Medicago sativa for ensiling on dry matter intake, ruminal fermentation and liquid passage rate in twelve non pregnant dry cows. A randomized block design was used and the treatments were alfalfa haylage control (60% DM and 19.5% CP or inoculated with Silobac® product (Lactobacillus plantarum and Pediococcus pentosaceus. Experimental diet contained 50% of alfalfa silage and 50% of concentrate. Experimental period lasted for twenty-one days; the 21st day was used for ruminal liquid sampling at 0, 2, 4, 6, 8, 10 e 12 hours

Risks and benefits of compost-like materials prepared by the thermal treatment of raw scallop hepatopancreas for supplying cadmium and the growth of alfalfa (Medicago sativa L.).

Science.gov (United States)

Ushijima, Kensuke; Fukushima, Masami; Kanno, Shinya; Kanno, Itoko; Ohnishi, Mitsuhiro

2016-01-01

Scallop hepatopancreas, fishery waste, contains relatively high levels of Cd and organic nitrogen compounds, the latter of which represent a fertilizer. In this study, raw scallop hepatopancreas tissue was thermally treated with sawdust and red loam in the presence of an iron catalyst to produce compost-like materials (CLMs). Two CLM samples were prepared by varying the content of raw scallop hepatopancreas tissue: 46 wt.% for CLM-1 and 18 wt.% for CLM-2. Mixtures of control soil (CTL) and CLMs (CLM content: 10 and 25 wt.%) were examined for the growth of alfalfa (Medicago sativa L.) to evaluate the risks and benefits of using this material for fertilization. The Cd content in shoots and roots of alfalfa, that were grown in the presence of CLMs, was significantly higher than those for the plants grown in the CTL, indicating that Cd had accumulated in the plants from CLMs. The accumulation of Cd in the alfalfa roots was quite high in the case of the 25% CLM-1 sample. However, alfalfa growth was significantly promoted in the presence of 10% CLM-1. This can be attributed to the higher levels of nitrogen and humic substances, which serve as fertilizer components. Although the fertilization effect in case of CLM-1showed a potential benefit, the accumulation of Cd in alfalfa was clearly increased in the presence of both CLMs. In conclusion, the use of CLMs produced from raw scallop hepatopancreas tissue can be considered to have a desirable benefit from standpoint of its use as fertilizer, but is accompanied by a risk of the accumulation of Cd in alfalfa plants.

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

Science.gov (United States)

Li, Daofeng; Su, Zhen; Dong, Jiangli; Wang, Tao

2009-11-11

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. 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. 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/.

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/.

Arbuscular Mycorrhizal Fungi Elicit a Novel Intracellular Apparatus in Medicago truncatula Root Epidermal Cells before InfectionW⃞

Science.gov (United States)

Genre, Andrea; Chabaud, Mireille; Timmers, Ton; Bonfante, Paola; Barker, David G.

2005-01-01

The penetration of arbuscular mycorrhizal (AM) fungi through the outermost root tissues of the host plant is a critical step in root colonization, ultimately leading to the establishment of this ecologically important endosymbiotic association. To evaluate the role played by the host plant during AM infection, we have studied in vivo cellular dynamics within Medicago truncatula root epidermal cells using green fluorescent protein labeling of both the plant cytoskeleton and the endoplasmic reticulum. Targeting roots with Gigaspora hyphae has revealed that, before infection, the epidermal cell assembles a transient intracellular structure with a novel cytoskeletal organization. Real-time monitoring suggests that this structure, designated the prepenetration apparatus (PPA), plays a central role in the elaboration of the apoplastic interface compartment through which the fungus grows when it penetrates the cell lumen. The importance of the PPA is underlined by the fact that M. truncatula dmi (for doesn't make infections) mutants fail to assemble this structure. Furthermore, PPA formation in the epidermis can be correlated with DMI-dependent transcriptional activation of the Medicago early nodulin gene ENOD11. These findings demonstrate how the host plant prepares and organizes AM infection of the root, and both the plant–fungal signaling mechanisms involved and the mechanistic parallels with Rhizobium infection in legume root hairs are discussed. PMID:16284314

Disponibilidade hídrica relacionada ao conteúdo de nitrogênio e à produtividade da alfafa (Medicago sativa L.

Directory of Open Access Journals (Sweden)

Oliveira Wladecir Salles de

2003-01-01

Full Text Available A variação da abundância isotópica do 13C e fixação biológica do nitrogênio podem ser utilizadas em programas de melhoramento de cultivares de alfafa (Medicago sativa L., pois contribuem para o entendimento de processos fisiológicos relacionados ao uso da água, fotossíntese, obtenção e uso do nitrogênio, bem como suas interdependências e efeitos sobre a produtividade, eficiência do uso da água e qualidade da biomassa produzida. Nesse sentido, torna-se necessária a avaliação do desempenho sob condições contrastantes em disponibilidade hídrica. Neste estudo, avaliou-se o desempenho de 12 e 6 cultivares de alfafa, respectivamente, em dois experimentos instalados em lisímetros no delineamento estatístico de parcelas subdivididas sob irrigação constante e regime de chuvas. Sob condições controladas, a alfafa responde positivamente à irrigação tanto em relação aos caracteres quantitativos quanto qualitativos e dentre os cultivares estudados, os cultivares Crioula Brasileira e Crioula Chilena apresentaram os melhores desempenhos. Na avaliação de seis meses de duração, não houve correlação entre a discriminação isotópica do carbono (DIC, fixação biológica de nitrogênio (FBN, produção de matéria seca (PMS e eficiência do uso da água (EUA. Na avaliação de um ano sob irrigação a DIC correlacionou-se negativamente com PMS (-0,92**, EUA (-0,94** e FBN (-0,79*. A FBN correlacionou-se positivamente com a PMS (0,93** e EUA (0,87*. Sob regime de chuva não houve correlação entre os parâmetros. Existe uma tendência de correlação positiva entre a PMS e DIC demonstrada em inúmeros trabalhos científicos. Essa tendência pode ser alterada sob limitação de água, limitação ao desenvolvimento radicular ou quando o conjunto de cultivares analisadas é contrastante. Se a correlação permanece de forma positiva invariável, não existe possibilidade de aumento da EUA, uma vez que o aumento da DIC �

Decomposition of olive mill waste compost, goat manure and Medicago sativa in Lebanese soils using the litterbag technique

Science.gov (United States)

Atallah, Therese

2014-05-01

Organic amendments, green manure and plant residues incorporation are the main sources of nutrients in organic farming, their decomposition rate is crucial for the accumulation and long-term storage of organic matter in soils. In this study the decomposition of compost from olive mill waste (N: 29.3 g kg-1; total dissolved nitrogen or TDN: 3.82 g kg-1), goat manure (N: 31.5 g kg-1; TDN: 0.94 g kg-1), the shoots (N: 33.6 g kg-1; TDN: 17.57 g kg-1) and roots (N: 22.12 g kg-1; TDN: 8.87 g kg-1) of Medicago sativa was followed in three Lebanese soils. The nitrogen, phosphorus and potassium released were followed over one year, starting in early winter (December-January). The mild sub-humid Mediterranean conditions allowed a rapid mass loss in alfalfa shoots 30 days after incorporation. Manure and compost were more persistent. Between 80 and 90% of TDN were released, after 30 days of in-situ incubation for compost, the release was over 90% for alfalfa shoots. The movement of P was slower, as the compost (6.99 g kg-1 of P) and manure (9.81 g kg-1 of P) lost 33% and 22%, respectively, during 30 days of incubation. After one year, 15 to 35% of P remained in the soils. The manure was the richest in potassium (19.66 g kg-1) followed by the alfalfa shoots (15.56 g kg-1), the compost (8.19 g kg-1) and the roots (5.96 g kg-1). The loss of potassium was important, as over 88% had disappeared over the year. All decomposition curves followed an exponential model. The calculated coefficients of decomposition for total nitrogen (lnfinal - lninitial/days) were significantly higher for alfalfa shoots (0.00547 day-1) and similar for the compost (0.00184 day-1) and the manure (0.00175 day-1). The ANOVA test showed a difference between two of the sites (Site A: 521 g kg-1 of clay and 42 g kg-1 of calcium carbonate; Site S: 260 g kg-1 of clay and 269 g kg-1 of CaCO3) and the third one (Site L: 315 g kg-1 of clay and 591 g kg-1 of CaCO3). The relationships between the soil calcium

Alfalfa (Medicago sativa L.) is tolerant to higher levels of salinity than previous guidelines indicated: Implications of field and greenhouse studies

Science.gov (United States)

Putnam, Daniel H.; Benes, Sharon; Galdi, Giuliano; Hutmacher, Bob; Grattan, Steve

2017-04-01

Alfalfa (Medicago sativa L.) is the most widely grown leguminous forage crop in North America and is valued for high productivity, quality, economic value, and for dairy productivity. Alfalfa has historically been classified as moderately sensitive to saline conditions, with yield declines predicted at >2 dS/m in the saturated soil paste extract. However, greenhouse, sand tank, and field studies over the past five years have confirmed that alfalfa can be grown with limited negative effects at much higher salinity levels. A broad collection of alfalfa varieties has exhibited a range of resistance at irrigation water salinities >5 dS/m ECw in greenhouse trials, with significant variation due to variety. USDA-ARS sand tank studies indicated similar or greater tolerances closer to 8 dS/m in the soil water, in addition to confirmation of significant varietal differences. A three-year field study on clay loam soil with applications of 5-7 dS/m ECw irrigation water indicated normal yields and excellent stand survivability. A second field study in the same soil type with levels from 8-10 dS/m ECw showed yield reductions of 10-15% but economic yields were still achieved at those levels. Field and greenhouse studies were conducted with mixed salt saline sodic waters typical of the San Joaquin Valley of California. Field evaluation of variety performance was subject to greater variation due to secondary salinity-soil interactions including water infiltration and crusting problems, not only salinity per-se. Thus, adequate irrigation water availability to the crop may be as important as salinity in impacting yields under field conditions. Once established, the deep-rooted characteristics of alfalfa enable utilization of deeper subsurface moisture, even at moderate to high salinity levels, as documented by USDA lysimeter studies. Significant advantages to salinity-tolerant varieties have been observed. It will be important to consider specific management factors which may enable

Medicago truncatula CYP716A12 is a multifunctional oxidase involved in the biosynthesis of hemolytic saponins.

Science.gov (United States)

Carelli, Maria; Biazzi, Elisa; Panara, Francesco; Tava, Aldo; Scaramelli, Laura; Porceddu, Andrea; Graham, Neil; Odoardi, Miriam; Piano, Efisio; Arcioni, Sergio; May, Sean; Scotti, Carla; Calderini, Ornella

2011-08-01

Saponins, a group of glycosidic compounds present in several plant species, have aglycone moieties that are formed using triterpenoid or steroidal skeletons. In spite of their importance as antimicrobial compounds and their possible benefits for human health, knowledge of the genetic control of saponin biosynthesis is still poorly understood. In the Medicago genus, the hemolytic activity of saponins is related to the nature of their aglycone moieties. We have identified a cytochrome P450 gene (CYP716A12) involved in saponin synthesis in Medicago truncatula using a combined genetic and biochemical approach. Genetic loss-of-function analysis and complementation studies showed that CYP716A12 is responsible for an early step in the saponin biosynthetic pathway. Mutants in CYP716A12 were unable to produce hemolytic saponins and only synthetized soyasaponins, and were thus named lacking hemolytic activity (lha). In vitro enzymatic activity assays indicate that CYP716A12 catalyzes the oxidation of β-amyrin and erythrodiol at the C-28 position, yielding oleanolic acid. Transcriptome changes in the lha mutant showed a modulation in the main steps of triterpenic saponin biosynthetic pathway: squalene cyclization, β-amyrin oxidation, and glycosylation. The analysis of CYP716A12 expression in planta is reported together with the sapogenin content in different tissues and stages. This article provides evidence for CYP716A12 being a key gene in hemolytic saponin biosynthesis.

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.

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 second method involves infiltration of young seedlings with Agrobacterium. In both cases a proportion of the progeny of the infiltrated plants is transformed. The transformation frequency ranges from 4.7 to 76% for the flower infiltration method, and from 2.9 to 27.6% for the seedling infiltration method....... Both procedures resulted in a mixture of independent transformants and sibling transformants. The transformants were genetically stable, and analysis of the T-2 generation indicates that the transgenes are inherited in a Mendelian fashion. These transformation systems will increase the utility of M...

Root and Nodulation Phenotypes of the Ethylene-Insensitive Sickle Mutant of Medicago truncatula

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JOKO PRAYITNO

2010-09-01

Full Text Available The sickle (skl mutant of the model legume Medicago truncatula is an ethylene-sensitive mutant that have a ten-fold increase in nodule numbers. The nodulation and root phenotypes of the skl mutant were investigated and further characterised. The skl mutant had longer roots than the wild type, but when inoculated with Sinorhizobium, its root length was reduced to the level of wild type. Furthermore, lateral root numbers in uninoculated skl were similar to those in uninoculated wild type. However, when the root tips were decapitated, fewer lateral roots formed in skl than in wild type. Nodule numbers of the skl mutant were significantly reduced by low nitrate concentration (2.5 mM. These results suggest that skl mutant has alterations in both root and nodule development.

Loss of function of cinnamyl alcohol dehydrogenase 1 leads to unconventional lignin and a temperature-sensitive growth defect in Medicago truncatula

OpenAIRE

Zhao, Qiao; Tobimatsu, Yuki; Zhou, Rui; Pattathil, Sivakumar; Gallego-Giraldo, Lina; Fu, Chunxiang; Jackson, Lisa A.; Hahn, Michael G.; Kim, Hoon; Chen, Fang; Ralph, John; Dixon, Richard A.

2013-01-01

There is considerable debate over the capacity of the cell wall polymer lignin to incorporate unnatural monomer units. We have identified Tnt1 retrotransposon insertion mutants of barrel medic (Medicago truncatula) that show reduced lignin autofluorescence under UV microscopy and red coloration in interfascicular fibers. The phenotype is caused by insertion of retrotransposons into a gene annotated as encoding cinnamyl alcohol dehydrogenase, here designated M. truncatula CAD1. NMR analysis in...

Medicago truncatula CYP716A12 Is a Multifunctional Oxidase Involved in the Biosynthesis of Hemolytic Saponins[W

Science.gov (United States)

Carelli, Maria; Biazzi, Elisa; Panara, Francesco; Tava, Aldo; Scaramelli, Laura; Porceddu, Andrea; Graham, Neil; Odoardi, Miriam; Piano, Efisio; Arcioni, Sergio; May, Sean; Scotti, Carla; Calderini, Ornella

2011-01-01

Saponins, a group of glycosidic compounds present in several plant species, have aglycone moieties that are formed using triterpenoid or steroidal skeletons. In spite of their importance as antimicrobial compounds and their possible benefits for human health, knowledge of the genetic control of saponin biosynthesis is still poorly understood. In the Medicago genus, the hemolytic activity of saponins is related to the nature of their aglycone moieties. We have identified a cytochrome P450 gene (CYP716A12) involved in saponin synthesis in Medicago truncatula using a combined genetic and biochemical approach. Genetic loss-of-function analysis and complementation studies showed that CYP716A12 is responsible for an early step in the saponin biosynthetic pathway. Mutants in CYP716A12 were unable to produce hemolytic saponins and only synthetized soyasaponins, and were thus named lacking hemolytic activity (lha). In vitro enzymatic activity assays indicate that CYP716A12 catalyzes the oxidation of β-amyrin and erythrodiol at the C-28 position, yielding oleanolic acid. Transcriptome changes in the lha mutant showed a modulation in the main steps of triterpenic saponin biosynthetic pathway: squalene cyclization, β-amyrin oxidation, and glycosylation. The analysis of CYP716A12 expression in planta is reported together with the sapogenin content in different tissues and stages. This article provides evidence for CYP716A12 being a key gene in hemolytic saponin biosynthesis. PMID:21821776

Development of a GAL4-VP16/UAS trans-activation system for tissue specific expression in Medicago truncatula.

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Amélie Sevin-Pujol

Full Text Available Promoters with tissue-specific activity are very useful to address cell-autonomous and non cell autonomous functions of candidate genes. Although this strategy is widely used in Arabidopsis thaliana, its use to study tissue-specific regulation of root symbiotic interactions in legumes has only started recently. Moreover, using tissue specific promoter activity to drive a GAL4-VP16 chimeric transcription factor that can bind short upstream activation sequences (UAS is an efficient way to target and enhance the expression of any gene of interest. Here, we developed a collection of promoters with different root cell layers specific activities in Medicago truncatula and tested their abilities to drive the expression of a chimeric GAL4-VP16 transcription factor in a trans-activation UAS: β-Glucuronidase (GUS reporter gene system. By developing a binary vector devoted to modular Golden Gate cloning together with a collection of adapted tissue specific promoters and coding sequences we could test the activity of four of these promoters in trans-activation GAL4/UAS systems and compare them to "classical" promoter GUS fusions. Roots showing high levels of tissue specific expression of the GUS activity could be obtained with this trans-activation system. We therefore provide the legume community with new tools for efficient modular Golden Gate cloning, tissue specific expression and a trans-activation system. This study provides the ground work for future development of stable transgenic lines in Medicago truncatula.

Bioinformatics Analysis of MAPKKK Family Genes in Medicago truncatula

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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.

[Genome-wide identification and analysis of WRKY transcription factors in Medicago truncatula].

Science.gov (United States)

Song, Hui; Nan, Zhibiao

2014-02-01

WRKY gene family plays important roles in plant by involving in transcriptional regulations during various physiologically processes such as development, metabolism and responses to biotic and abiotic stresses. WRKY genes have been identified in various plants. However, only few WRKY genes in Medicago truncatula have been identified with systematic analysis and comparison. In this study, we identified 93 WRKY genes through analyses of M. truncatula genome. These genes include 19 type-I genes, 49 type II genes and 13 type-III genes, and 12 non-regular type genes. All of these genes were characterized through analyses of gene duplication, chromosomal locations, structural diversity, conserved protein motifs and phylogenetic relations. The results showed that 11 times of gene duplication event occurred in WRKY gene family involving 24 genes. WRKY genes, containing 6 gene clusters, are unevenly distributed into chromosome 1 to 6, and there is the purifying selection pressure in WRKY group III genes.

Genome-Wide Identification of Glyoxalase Genes in Medicago truncatula and Their Expression Profiling in Response to Various Developmental and Environmental Stimuli

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Ajit Ghosh

2017-06-01

Full Text Available Glyoxalase is an evolutionary highly conserved pathway present in all organisms. Conventional glyoxalase pathway has two enzymes, glyoxalase I (GLYI and glyoxalase II (GLYII that act sequentially to detoxify a highly cytotoxic compound methylglyoxal (MG to D-lactate with the help of reduced glutathione. Recently, proteins with DJ-1/PfpI domain have been reported to perform the same conversion in a single step without the help of any cofactor and thus termed as “unique glyoxalase III” enzyme. Genome-wide analysis of glyoxalase genes have been previously conducted in Arabidopsis, rice and Soybean plants, but no such study was performed for one of the agricultural important model legume species, Medicago truncatula. A comprehensive genome-wide analysis of Medicago identified a total of putative 29 GLYI, 14 GLYII genes, and 5 glyoxalase III (DJ-1 genes. All these identified genes and their corresponding proteins were analyzed in detail including their chromosomal distribution, gene duplication, phylogenetic relationship, and the presence of conserved domain(s. Expression of all these genes was analyzed in different tissues as well as under two devastating abiotic stresses- salinity and drought using publicly available transcript data. This study revealed that MtGLYI-4, MtGLYII-6, and MtDJ-1A are the constitutive members with a high level of expression at all 17 analyzed tissues; while MtGLYI-1, MtGLYI-11, MtGLYI-5, MtGLYI-7, and MtGLYII-13 showed tissue-specific expression. Moreover, most of the genes displayed similar pattern of expression in response to both salinity and drought stress, irrespective of stress duration and tissue type. MtGLYI-8, MtGLYI-11, MtGLYI-6, MtGLYI-16, MtGLYI-21, and MtGLYII-9 showed up-regulation, while MtGLYI-17 and MtGLYI-7/9 showed down-regulation in response to both stresses. Interestingly, MtGLYI-14/15 showed completely opposite pattern of expression in these two stresses. This study provides an initial basis

Nod Factor Effects on Root Hair-Specific Transcriptome of Medicago truncatula: Focus on Plasma Membrane Transport Systems and Reactive Oxygen Species Networks.

OpenAIRE

Damiani , Isabelle; Drain , Alice; Guichard , Marjorie; Balzergue , Sandrine; Boscari , Alexandre; Boyer , Jean-Christophe; Brunaud , Véronique; Cottaz , Sylvain; Rancurel , Corinne; Da Rocha , Martine; Fizames , Cécile; Fort , Sébastien; Gaillard , Isabelle; MAILLOL , Vincent; Danchin , Etienne G J

2015-01-01

International audience; Root hairs are involved in water and nutrient uptake, and thereby in plant autotrophy. In legumes, they also play a crucial role in establishment of rhizobial symbiosis. To obtain a holistic view of Medicago truncatula genes expressed in root hairs and of their regulation during the first hours of the engagement in rhizobial symbiotic interaction, a high throughput RNA sequencing on isolated root hairs from roots challenged or not with lipochitooligosaccharides Nod fac...

Evaluation of Perennial Forage Legumes and Herbs in Six Mediterranean Environments Evaluación de Leguminosas y Hierbas Forrajeras Perennes en Seis Medioambientes Mediterráneos

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Daniel Real

2011-09-01

Full Text Available There is an absence of drought tolerant herbaceous perennial forage legume and herb options other than lucerne (Medicago sativa L. for environments with Mediterranean-like climates common in extensive areas of Southern Australia, the Mediterranean basin, and Chile. Therefore, a collection of 174 forage perennial legume and herb entries from 103 species and 32 genera was evaluated for adaptation in a diverse range of Mediterranean climatic environments in Southern Australia. The seasonal rainfall distribution varied from moderately to highly winter dominant with long term average annual rainfall ranging from 318 to 655 mm. The entries were rated for productivity and persistence over 3 yr. The 12 entries identified as the most promising for winter, summer, or all-year round production included Bituminaria bituminosa (L. C.H. Stirt. var. albomarginata; Cichorium intybus L.; Cullen australasicum (Schltdl. J.W. Grimes; Dorycnium hirsutum (L. Ser.; Kennedia prostrata R. Br.; Lotononis bainesii Baker, Lotus pedunculatus Cav.; L. corniculatus L.; L. cytisoides L.; Medicago sativa subsp. sativa L.; Medicago sativa subsp. caerulea (Less. ex Ledeb. Schmalh., and M. sativa subsp. falcata (L. Arcang. These entries maintained production and persisted for the period of the evaluation, with the exception of C. intybus and L. corniculatus that declined in persistence over time. The potential role of these species in extensive grazing systems in Mediterranean climatic zones, their attributes and limitations, and current progress in developing them as useful forage plants was discussed.Existe una escasez de leguminosas y hierbas perennes herbáceas además de alfalfa (Medicago sativa L. tolerantes a sequía para ambientes con clima mediterráneo como los que se encuentran en el Sur de Australia, el Mediterráneo y Chile. Por lo tanto, una colección de 174 leguminosas perennes y hierbas correspondientes a 103 especies y 32 géneros fue evaluada por su adaptaci

Medicago sativa spp. falcata

African Journals Online (AJOL)

STORAGESEVER

2009-05-18

May 18, 2009 ... The aim of this study was to assess the genetic diversity of ... Regression analysis showed no relationship between genetic distance and phenotypic distance. ... For legumes, growth habit, flower color, leaf ..... 47.49±1.877abc.

Nod factor effects on root hair-specific transcriptome of Medicago truncatula: focus on plasma membrane transport systems and reactive oxygen species networks

OpenAIRE

Isabelle eDAMIANI; Alice eDRAIN; Marjorie eGUICHARD; Sandrine eBALZERGUE; Sandrine eBALZERGUE; Alexandre eBOSCARI; Jean-Christophe eBOYER; Véronique eBRUNAUD; Véronique eBRUNAUD; Sylvain eCOTTAZ; Sylvain eCOTTAZ; Corinne eRANCUREL; Martine eDa Rocha; Cécile eFIZAMES; Sebastien eFORT

2016-01-01

Root hairs are involved in water and nutrient uptake, and thereby in plant autotrophy. In legumes, they also play a crucial role in establishment of rhizobial symbiosis. To obtain a holistic view of Medicago truncatula genes expressed in root hairs and of their regulation during the first hours of the engagement in rhizobial symbiotic interaction, a high throughput RNA sequencing on isolated root hairs from roots challenged or not with lipochitooligosaccharides Nod factors (NF) for 4 h or 20 ...

MediPlEx - a tool to combine in silico & experimental gene expression profiles of the model legume Medicago truncatula

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Stutz Leonhard J

2010-10-01

Full Text Available Abstract Background Expressed Sequence Tags (ESTs are in general used to gain a first insight into gene activities from a species of interest. Subsequently, and typically based on a combination of EST and genome sequences, microarray-based expression analyses are performed for a variety of conditions. In some cases, a multitude of EST and microarray experiments are conducted for one species, covering different tissues, cell states, and cell types. Under these circumstances, the challenge arises to combine results derived from the different expression profiling strategies, with the goal to uncover novel information on the basis of the integrated datasets. Findings Using our new analysis tool, MediPlEx (MEDIcago truncatula multiPLe EXpression analysis, expression data from EST experiments, oligonucleotide microarrays and Affymetrix GeneChips® can be combined and analyzed, leading to a novel approach to integrated transcriptome analysis. We have validated our tool via the identification of a set of well-characterized AM-specific and AM-induced marker genes, identified by MediPlEx on the basis of in silico and experimental gene expression profiles from roots colonized with AM fungi. Conclusions MediPlEx offers an integrated analysis pipeline for different sets of expression data generated for the model legume Medicago truncatula. As expected, in silico and experimental gene expression data that cover the same biological condition correlate well. The collection of differentially expressed genes identified via MediPlEx provides a starting point for functional studies in plant mutants. MediPlEx can freely be used at http://www.cebitec.uni-bielefeld.de/mediplex.

Genome-Wide Association Mapping of Loci Associated with Plant Growth and Forage Production under Salt Stress in Alfalfa (Medicago sativa L.

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Xiang-Ping Liu

2017-05-01

Full Text Available Salinity tolerance is highly desirable to sustain alfalfa production in marginal lands that have been rendered saline. In this study, we used a diverse panel of 198 alfalfa accessions for mapping loci associated with plant growth and forage production under salt stress using genome-wide association studies (GWAS. The plants were genotyped using genotyping-by-sequencing (GBS. A greenhouse procedure was used for phenotyping four agronomic and physiological traits affected by salt stress, including dry weight (DW, plant height (PH, leaf chlorophyll content (LCC, and stomatal conductance (SC. For each trait, a stress susceptibility index (SSI was used to evaluate plant performance under stressed and non-stressed conditions. Marker-trait association identified a total of 42 markers significantly associated with salt tolerance. They were located on all chromosomes except chromosome 2 based on the alignment of their flanking sequences to the reference genome (Medicago truncatula. Of those identified, 13 were associated with multiple traits. Several loci identified in the present study were also identified in previous reports. BLAST search revealed that 19 putative candidate genes linked to 24 significant markers. Among them, B3 DNA-binding protein, Thiaminepyrophosphokinase and IQ calmodulin-binding motif protein were identified among multiple traits in the present and previous studies. With further investigation, these markers and candidates would be useful for developing markers for marker-assisted selection in breeding programs to improve alfalfa cultivars with enhanced tolerance to salt stress.

In silico identification, phylogeny and expression analysis of expansin superfamily in Medicago truncatula

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Ying Liu

2016-01-01

Full Text Available Expansins are important components of plant cell walls, which are involved in the process of cell wall loosening under low extracellular pH. By using a combinational method for homology search and protein domain analysis, a total of 42 expansin genes were identified from Medicago truncatula genome in this study. They were divided into four families, based on sequence alignment and phylogenetic analysis. Gene duplication events were identified in the expansins superfamily, especially in the extension of α-expansin family. By analysis of RNA-sequencing data from National Center for Biotechnology Information, the expansin (EXP genes expressed during tissues development were characterized. Meanwhile, lots of cis-acting regulatory DNA elements in the EXP superfamily were identified, which were mainly related to plant growth and development processes. The results presented in this study are expected to facilitate further research works on this gene superfamily and provide new insights about the molecular mechanisms of expansins in M. truncatula.

Host-secreted antimicrobial peptide enforces symbiotic selectivity in Medicago truncatula.

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Wang, Qi; Yang, Shengming; Liu, Jinge; Terecskei, Kata; Ábrahám, Edit; Gombár, Anikó; Domonkos, Ágota; Szűcs, Attila; Körmöczi, Péter; Wang, Ting; Fodor, Lili; Mao, Linyong; Fei, Zhangjun; Kondorosi, Éva; Kaló, Péter; Kereszt, Attila; Zhu, Hongyan

2017-06-27

Legumes engage in root nodule symbioses with nitrogen-fixing soil bacteria known as rhizobia. In nodule cells, bacteria are enclosed in membrane-bound vesicles called symbiosomes and differentiate into bacteroids that are capable of converting atmospheric nitrogen into ammonia. Bacteroid differentiation and prolonged intracellular survival are essential for development of functional nodules. However, in the Medicago truncatula - Sinorhizobium meliloti symbiosis, incompatibility between symbiotic partners frequently occurs, leading to the formation of infected nodules defective in nitrogen fixation (Fix - ). Here, we report the identification and cloning of the M. truncatula NFS2 gene that regulates this type of specificity pertaining to S. meliloti strain Rm41. We demonstrate that NFS2 encodes a nodule-specific cysteine-rich (NCR) peptide that acts to promote bacterial lysis after differentiation. The negative role of NFS2 in symbiosis is contingent on host genetic background and can be counteracted by other genes encoded by the host. This work extends the paradigm of NCR function to include the negative regulation of symbiotic persistence in host-strain interactions. Our data suggest that NCR peptides are host determinants of symbiotic specificity in M. truncatula and possibly in closely related legumes that form indeterminate nodules in which bacterial symbionts undergo terminal differentiation.

Gene expression analysis of molecular mechanisms of defense induced in Medicago truncatula parasitized by Orobanche crenata.

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Die, José Vicente; González Verdejo, Clara I; Dita, Miguel A; Nadal, Salvador; Román, Belén

2009-07-01

The infection of Medicago truncatula Gaertn. roots with the obligate parasite Orobanche crenata Forsk. is a useful model for studying the molecular events involved in the legumes-parasite interaction. In order to gain insight into the identification of gene-regulatory elements involved in the resistance mechanism, the temporal expression pattern of ten defense-related genes was carried out using real-time quantitative reverse-transcription polymerase chain reaction assays. The induction of all of the analyzed transcripts significantly increased over a range from 2- to 321-fold higher than the control depending on the gene and time point. The transcriptional changes observed in response to O. crenata infection suggest that resistance could rely on both, the induction of general defense-related genes and more specific responses.

Observations of foliar injury to plants by sulfur dioxide

Energy Technology Data Exchange (ETDEWEB)

Banerjee, A.K.; Chaphekar, S.B.

1978-01-01

Morphological and anatomical changes in mature leaves indicated that Raphanus sativus, Commelina benghalensis and Medicago sativa were injured and Pennisetum typhoideum, Alternanthere ficoidea and Mangifera indica (seedlings) were not injured by sulfur dioxide fumigation. The highly susceptible plants like Raphanus, Medicago, and Commelina can be used for monitoring air quality in a polluted atmosphere. Uninjured species like Pennisetum on the other hand, may be grown in polluted areas for maintaining agricultural production. 9 references, 1 table.

Preliminary results on agronomic performance of barrel medic (Medicago truncatula in Serbia

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Mihailović Vojislav

2011-01-01

Full Text Available A small-plot trial with eight Australian barrel medic (Medicago truncatula Gaertn cultivars was carried out in 2010 at Rimski Šančevi. The average green forage and forage dry matter yields were highest in Jemalong (30.7 t ha-1 and 7.3 t ha-1 and Parabinga (30.7 t ha-1 and 8.0 t ha-1. Forage dry matter crude protein content ranged between 150.8 g kg-1 in Parabinga and 179.4 g kg-1 in Jester. Forage neutral detergent fibre content varied from 305.2 g kg-1 in Sephi to 458.8 g kg-1 in Caliph, while the average forage acid detergent fibre content was 312.8 g kg-1. The average seed yield for all cultivars was 281 kg ha-1 and may be considered satisfying, as it was obtained in a very rainy and warm growing season. Jemalong and Parabinga had the highest aboveground nitrogen yield (190 kg ha-1 and 193 kg ha-1 and thus the greatest potential for green manure.

A novel gene whose expression in Medicago truncatula roots is suppressed in response to colonization by vesicular-arbuscular mycorrhizal (VAM) fungi and to phosphate nutrition.

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Burleigh, S H; Harrison, M J

1997-05-01

A cDNA clone (Mt4) was isolated as a result of a differential screen to identify genes showing altered expression during the interaction between Medicago truncatula and the vesicular-arbuscular mycorrhizal (VAM) fungus Glomus versiforme. Mt4 represents a M. truncatula mRNA that contains numerous short open reading frames, the two longest of which are predicted to encode polypeptides of 51 amino acids each. One of these open reading frames shares a short region of identity with a phosphate starvation-inducible gene from tomato. Mt4 gene expression is regulated in response to colonization by mycorrhizal fungi: transcripts were detected in non-colonized roots and levels decreased in both M. truncatula and M. sativa (alfalfa) roots after colonization by G. versiforme. Transcript levels also decreased during the incomplete interaction between G. versiforme and a M. sativa mycorrhizal minus (myc-) line, indicating that the down-regulation of this gene occurs early during the interaction between the fungus and its host plant. Phosphate levels in the nutrient media also affected the expression of the Mt4 gene: transcripts were present in the roots of plants grown under phosphate-deficient conditions, but were undetectable in the roots of plants grown under phosphate sufficient conditions. Furthermore, expression was only observed when plants were grown under nitrogen-sufficient conditions. Northern blot analyses indicate that Mt4 transcripts are present primarily in roots and barely detectable in stems or leaves. Thus, Mt4 represents a M. truncatula gene whose expression is regulated in response to both colonization by mycorrhizal fungi and to the phosphate status of the plant.

Effects of drought and salt stress on seed germination of three ...

African Journals Online (AJOL)

The seeds of Medicago sativa (L.), Astragalus adsurgens (Pall.) and Coronilla varia (L.) were evaluated at germination for tolerance to salt (NaCl) and drought conditions induced by polyethylene glycol (PEG) in an experiment of orthogonal design. The results reveal that the germination percentages of M. sativa and A.

The promotive effect of N 2 fixers, Bacillus circulans and ...

African Journals Online (AJOL)

The promotive effect of N 2 fixers, Bacillus circulans and Saccharomyces cerevisiae on the viability of native arbuscular mycorrhizal fungi and the impact on the productivity of alfalfa ( Medicago sativa l.)

Medicago truncatula and Glomus intraradices gene expression in cortical cells harboring arbuscules in the arbuscular mycorrhizal symbiosis

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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

Medicago truncatula contains a second gene encoding a plastid located glutamine synthetase exclusively expressed in developing seeds

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Seabra Ana R

2010-08-01

Full Text Available Abstract Background Nitrogen is a crucial nutrient that is both essential and rate limiting for plant growth and seed production. Glutamine synthetase (GS, occupies a central position in nitrogen assimilation and recycling, justifying the extensive number of studies that have been dedicated to this enzyme from several plant sources. All plants species studied to date have been reported as containing a single, nuclear gene encoding a plastid located GS isoenzyme per haploid genome. This study reports the existence of a second nuclear gene encoding a plastid located GS in Medicago truncatula. Results This study characterizes a new, second gene encoding a plastid located glutamine synthetase (GS2 in M. truncatula. The gene encodes a functional GS isoenzyme with unique kinetic properties, which is exclusively expressed in developing seeds. Based on molecular data and the assumption of a molecular clock, it is estimated that the gene arose from a duplication event that occurred about 10 My ago, after legume speciation and that duplicated sequences are also present in closely related species of the Vicioide subclade. Expression analysis by RT-PCR and western blot indicate that the gene is exclusively expressed in developing seeds and its expression is related to seed filling, suggesting a specific function of the enzyme associated to legume seed metabolism. Interestingly, the gene was found to be subjected to alternative splicing over the first intron, leading to the formation of two transcripts with similar open reading frames but varying 5' UTR lengths, due to retention of the first intron. To our knowledge, this is the first report of alternative splicing on a plant GS gene. Conclusions This study shows that Medicago truncatula contains an additional GS gene encoding a plastid located isoenzyme, which is functional and exclusively expressed during seed development. Legumes produce protein-rich seeds requiring high amounts of nitrogen, we postulate

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.

Toxicities of TNT and RDX to Terrestrial Plants in Five Soils with Contrasting Characteristics

Science.gov (United States)

2013-07-01

lettuce ( Lactuca sativa (L.)) and barley (Hordeum vulgare (L.)), respectively, at analytically determined soil concentrations up to and including 3320... sativa L.), Japanese millet (J. millet; Echinochloa crus-galli L. [Beauv.]), and perennial ryegrass (Lolium perenne L.) in five natural soils that...of the test. The test species in these studies were Medicago sativa (L.) var. Canada no. 1 (alfalfa), Echinochloa crus-galli (L.) P. Beauv. var

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

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Vaz Patto, Maria Carlota; Rubiales, Diego

2014-01-01

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 (NHR) 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 NHR 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 NHR mechanisms to breed for broad-spectrum resistance to rust in legume species. PMID:25426128

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

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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.

Identification and network-enabled characterization of auxin response factor genes in Medicago truncatula

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David J. Burks

2016-12-01

Full Text Available The Auxin Response Factor (ARF family of transcription factors is an important regulator of environmental response and symbiotic nodulation in the legume Medicago truncatula. While previous studies have identified members of this family, a recent spurt in gene expression data coupled with genome update and reannotation calls for a reassessment of the prevalence of ARF genes and their interaction networks in M. truncatula. We performed a comprehensive analysis of the M. truncatula genome and transcriptome that entailed search for novel ARF genes and the co-expression networks. Our investigation revealed 8 novel M. truncatula ARF (MtARF genes, of the total 22 identified, and uncovered novel gene co-expression networks as well. Furthermore, the topological clustering and single enrichment analysis of several network models revealed the roles of individual members of the MtARF family in nitrogen regulation, nodule initiation, and post-embryonic development through a specialized protein packaging and secretory pathway. In summary, this study not just shines new light on an important gene family, but also provides a guideline for identification of new members of gene families and their functional characterization through network analyses.

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

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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.

ECONOMIC VALUE OF SOME LEGUMINOUS PLANT SPECIES OF THE COLLECTIONS FROM THE BOTANICAL GARDEN (INSTITUTE OF THE ACADEMY OF SCIENCES OF MOLDOVA

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Alexandru TELEUTA

2016-12-01

Full Text Available The results of the evaluation of the growth and development rates, the seed productivity, the green mass yield, the biochemical composition and the content of amino acids, phosphorous and calcium, the nutritive and energy value of the forage, as well as the biomethane productivity of local ecotypes of the leguminous species maintained in monoculture, in the collection of the Botanical Garden (Institute of the Academy of Sciences of Moldova (BG ASM: Astragalus ponticus, Coronilla varia, Lotus corniculatus, Medicago falcata, Onobrychis arenaria and Trifolium repens are presented in this article. Control variants – the traditional forage crops: Medicago sativa and Onobrychis viciifolia. The local ecotypes of the studied leguminous species were characterized by different growth and development rates. Coronilla varia and Lotus corniculatus, in the 2nd-3rd years, could be harvested, for the first time, 5 days earlier than Medicago sativa, but Medicago falcata and Onobrychis viciifolia – 18 days later. The green mass yield varied from 0.83 kg/m2 to 4.08 kg/m2. The studied ecotypes reached amounts of 0.60-0.89 nutritive units/kg and metabolizable energy 8.05-9.90 MJ/kg of dry matter, the content of digestible protein, of 106.28-225.09 g/nutritive unit, met the zootechnical standards; seed production: 19.12-83.00 g/m2; the biomethane yield ranged from 692 to 3197 m3/ha. Higher yield of natural forage, dry matter and biomethane was produced by Onobrychis arenaria and Coronilla varia.

Transcript profiling of two alfalfa genotypes with contrasting cell wall composition in stems using a cross-species platform: optimizing analysis by masking biased probes

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Jung Hans-Joachim G

2010-05-01

Full Text Available Abstract Background The GeneChip® Medicago Genome Array, developed for Medicago truncatula, is a suitable platform for transcript profiling in tetraploid alfalfa [Medicago sativa (L. subsp. sativa]. However, previous research involving cross-species hybridization (CSH has shown that sequence variation between two species can bias transcript profiling by decreasing sensitivity (number of expressed genes detected and the accuracy of measuring fold-differences in gene expression. Results Transcript profiling using the Medicago GeneChip® was conducted with elongating stem (ES and post-elongation stem (PES internodes from alfalfa genotypes 252 and 1283 that differ in stem cell wall concentrations of cellulose and lignin. A protocol was developed that masked probes targeting inter-species variable (ISV regions of alfalfa transcripts. A probe signal intensity threshold was selected that optimized both sensitivity and accuracy. After masking for both ISV regions and previously identified single-feature polymorphisms (SFPs, the number of differentially expressed genes between the two genotypes in both ES and PES internodes was approximately 2-fold greater than the number detected prior to masking. Regulatory genes, including transcription factor and receptor kinase genes that may play a role in development of secondary xylem, were significantly over-represented among genes up-regulated in 252 PES internodes compared to 1283 PES internodes. Several cell wall-related genes were also up-regulated in genotype 252 PES internodes. Real-time quantitative RT-PCR of differentially expressed regulatory and cell wall-related genes demonstrated increased sensitivity and accuracy after masking for both ISV regions and SFPs. Over 1,000 genes that were differentially expressed in ES and PES internodes of genotypes 252 and 1283 were mapped onto putative orthologous loci on M. truncatula chromosomes. Clustering simulation analysis of the differentially expressed genes

Evaluation of three endemic Mediterranean plant species Atriplex halimus, Medicago lupulina and Portulaca oleracea for Phytoremediation of Ni, Pb and Zn

Science.gov (United States)

Chami, Ziad Al; Amer, Nasser; Bitar, Lina Al; Mondelli, Donato; Dumontet, Stefano

2013-04-01

The success of phytoremediation depends upon the identification of suitable plants species that hyperaccumulate/tolerate heavy metals and produce large amounts of biomass. In this study, three endemic Mediterranean plant species Atriplex halimus, Medicago lupulina and Portulaca oleracea, were grown hydroponically to assess their potential use in phytoremediation of Ni, Pb and Zn and biomass production. The objective of this research is to improve phytoremediation procedures by searching for a new endemic Mediterranean plant species which can be used for phytoremediation of low/moderate contamination in the Mediterranean arid and semiarid conditions and bioenergy production. The hydroponics experiment was carried out in a growth chamber using half strength Hoagland's solution as control (CTR) and 5 concentrations for Pb and Zn (5, 10, 25, 50 and 100 mg L-1) and 3 concentrations for Ni (1, 2, and 5 mg L-1). Complete randomized design with five replications was adopted. Main growth parameters (shoot and root dry weight, shoot and root length and chlorophyll content) were determined. Shoots and roots were analyzed for their metals contents. Some interesting contributions of this research are: (i) plant metal uptake efficiency ranked as follows: A. halimus > M. lupulina > P. oleracea, whereas heavy metal toxicity ranked as follows: Ni > Zn > Pb, (ii) none of the plant species was identified as hyperaccumulator, (iii) Atriplex halimus and Medicago lupulina can accumulate Ni, Pb and Zn in their roots, (iv) translocate small fraction to their above ground biomass, and (v) indicate moderate pollution levels of the environment. In addition, as they are a good biomass producer, they can be used in phytostabilisation of marginal lands and their above ground biomass can be used for livestock feeding as well for bioenergy production.

Uranium uptake and accumulation in plants from soil contaminated with uranium in different concentrations

International Nuclear Information System (INIS)

Zhao Luxue; Tang Yongjin; Luo Xuegang

2014-01-01

The plants of Medicago sativa L., Hibiscus esulentus L, Waterspinach, Amaranthus retroflexus and Abutilon theophrasti Medic were employed as the indicator to investigate the uranium uptake and accumulation from soils contaminated with uranium (UO_2 (CH_3COO)_2 · 2H_2O) of 25 mg · kg"-"l, 75 mg · kg"-"1, 125 mg · kg"-"l, 175 mg · kg"-"l respectively, in a pot experiment. The result shows that, U concentration in the aerial part and underground part of the whole plant increased with the rise of uranium concentration in the soils. In the contaminated soils with 25∼125 mg · kg"-"l concentrations of uranium, U content of Medicago sativa L is the highset (6.78 mg · kg"-"l, 61.53 mg · kg"-"l, 74.06 mg · kg"-"l separately). While in the 175 mg · kg"-"l concentration of uranium contaminated soils, U content of Hibiscus esulentus L is the highest (86.72 mg · kg"-"1), which is mainly because of U concentration in its roots have higher level of uranium (388.16 mg · kg"-"l). Comprehensive analysis shows that Medicago sativa L. is a good plant for phytoextraction and Hibiscus esulentus L is a good immobilizing plant for phytoremediation. The results can provide some theoretical basis and technical support for remedying U-contaminated soils in different areas of our country. (authors)

Transcription reprogramming during root nodule development in Medicago truncatula.

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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.

Alfalfa stem tissues: Cell wall deposition, composition, and degradability

NARCIS (Netherlands)

Jung, H.G.; Engels, F.M.

2002-01-01

Declining cell wall degradability of alfalfa (Medicago sativa L.) stems with maturation limits the nutritional value of alfalfa for ruminants. This study characterized changes in cell wall concentration, composition, and degradability by rumen microbes resulting from alfalfa stem tissue

Cover crop-based ecological weed management: exploration and optimization

NARCIS (Netherlands)

Kruidhof, H.M.

2008-01-01

Keywords: organic farming, ecologically-based weed management, cover crops, green manure, allelopathy, Secale cereale, Brassica napus, Medicago sativa

Cover crop-based ecological weed management: exploration and optimization. In organic farming systems, weed control is recognized as one

Efecto de las arañas (Arachnida: Araneae como depredadoras de insectos plaga en cultivos de alfalfa (Medicago sativa (Fabaceae en Argentina

Directory of Open Access Journals (Sweden)

Andrea Armendano

2011-12-01

Full Text Available Effect of spiders (Arachnida: Araneae as predators of insect pest in alfalfa crops (Medicago sativa (Fabaceae in Argentina. Spiders are predators that reduce insect pest populations in agroecosystems. Trials were conducted to measure the selectivity against different insect preys, the daily consumption, effect of predators alone and together with a known number of preys, and the indirect effect of predators on vegetation. For this, experimental units (1x1m were used covered with a fine plastic mesh. Misumenops pallidus, Oxyopes salticus and Araneus sp. were used as generalist predators, and aphids, weevils, locusts, chrysomelids and Lepidoptera larvae as their potential preys. Among the preys offered, the spiders preferred Lepidoptera larvae compared to the other two pests groups (weevils and aphids. The maximum consumption rate was of 93.33% for Lepidoptera larvae, 25.33% for aphids and 11.67% for weevils. The Q Index values for the three species of spiders showed a positive selectivity only for defoliating larvae. O. salticus showed the highest values of consumption rates while Rachiplusia nu was the most consumed. The maximum value of consumption in 24 hours was showed by O. salticus on R. nu (C=2.8. The association of several species of predatory spiders increased the total number of insects captured, and also showed that the addition of spiders caused a decrease in the number of leaves damaged by the effect of lepidopterous larvae. Rev. Biol. Trop. 59 (4: 1651-1662. Epub 2011 December 01Las arañas son depredadoras capaces de reducir las poblaciones de insectos plaga en agroecosistemas. Para medir la selectividad frente a distintas presas, se realizaron ensayos de consumo diario, efecto de los depredadores aisladamente y en conjunto sobre el número de presas y efecto indirecto de los depredadores sobre la vegetación; se utilizaron jaulas experimentales de 1x1m cubiertas con una fina malla plástica. Misumenops pallidus, Oxyopes salticus y

Medicago truncatula Zinc-Iron Permease6 provides zinc to rhizobia-infected nodule cells.

Science.gov (United States)

Abreu, Isidro; Saéz, Ángela; Castro-Rodríguez, Rosario; Escudero, Viviana; Rodríguez-Haas, Benjamín; Senovilla, Marta; Larue, Camille; Grolimund, Daniel; Tejada-Jiménez, Manuel; Imperial, Juan; González-Guerrero, Manuel

2017-11-01

Zinc is a micronutrient required for symbiotic nitrogen fixation. It has been proposed that in model legume Medicago truncatula, zinc is delivered by the root vasculature into the nodule and released in the infection/differentiation zone. There, transporters must introduce this element into rhizobia-infected cells to metallate the apoproteins that use zinc as a cofactor. MtZIP6 (Medtr4g083570) is an M. truncatula Zinc-Iron Permease (ZIP) that is expressed only in roots and nodules, with the highest expression levels in the infection/differentiation zone. Immunolocalization studies indicate that it is located in the plasma membrane of nodule rhizobia-infected cells. Down-regulating MtZIP6 expression levels with RNAi does not result in any strong phenotype when plants are fed mineral nitrogen. However, these plants displayed severe growth defects when they depended on nitrogen fixed by their nodules, losing of 80% of their nitrogenase activity. The reduction of this activity was likely an indirect effect of zinc being retained in the infection/differentiation zone and not reaching the cytosol of rhizobia-infected cells. These data are consistent with a model in which MtZIP6 would be responsible for zinc uptake by rhizobia-infected nodule cells in the infection/differentiation zone. © 2017 John Wiley & Sons Ltd.

Production of 2^nd 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...

Arabidopsis CDS blastp result: AK062499 [KOME

Lifescience Database Archive (English)

Full Text Available AK062499 001-104-A06 At4g27250.1 dihydroflavonol 4-reductase family / dihydrokaempferol... 4-reductase family similar to dihydrokaempferol 4-reductase, Ipomoea purpurea (GI:4239849), Medicago sativa, PIR2:S61416 8e-45 ...

Arabidopsis CDS blastp result: AK067272 [KOME

Lifescience Database Archive (English)

Full Text Available AK067272 J013098D22 At4g27250.1 dihydroflavonol 4-reductase family / dihydrokaempferol... 4-reductase family similar to dihydrokaempferol 4-reductase, Ipomoea purpurea (GI:4239849), Medicago sativa, PIR2:S61416 7e-40 ...

Arabidopsis CDS blastp result: AK099340 [KOME

Lifescience Database Archive (English)

Full Text Available AK099340 J033024N22 At4g27250.1 dihydroflavonol 4-reductase family / dihydrokaempferol... 4-reductase family similar to dihydrokaempferol 4-reductase, Ipomoea purpurea (GI:4239849), Medicago sativa, PIR2:S61416 2e-40 ...

NCBI nr-aa BLAST: CBRC-CJAC-01-0155 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-CJAC-01-0155 sp|Q09134|GRPA_MEDFA Abscisic acid and environmental stress-induc...ible protein emb|CAA42554.1| environmental stress and abscisic acid inducible protein [Medicago sativa subsp. falcata] Q09134 2e-05 35% ...

Investigation of Antileishmanial Effect of Alcoholic Extract and Essential Oil of Medicinal Plant Leaf Black Alfalfa (Medicago Lupulina), on The Number of Clinical Isolates of Leishmania Major Promastigotes in Vitro

OpenAIRE

E Gharirvand Eskandari; M Doudi

2016-01-01

Introduction: Leishmaniasis has created enormous global health problems. Side effects, drug resistance and the lack of effective vaccines had led to the new effective compounds effective of plants. The aim of this study was to introduce a traditional medicinal plant called Black alfalfa (Medicago Lupulina) that can be used as a valuable resource against cutaneous leishmaniasis. Methods: In this experimental study, alcoholic extract was prepared by maceration and essential oil by distillat...

Arabidopsis CDS blastp result: AK241480 [KOME

Lifescience Database Archive (English)

Full Text Available AK241480 J065165O08 At4g27250.1 68417.m03912 dihydroflavonol 4-reductase family / dihydrokaempferol... 4-reductase family similar to dihydrokaempferol 4-reductase, Ipomoea purpurea (GI:4239849), Medicago sativa, PIR2:S61416 4e-31 ...

Arabidopsis CDS blastp result: AK242505 [KOME

Lifescience Database Archive (English)

Full Text Available AK242505 J080309P03 At4g27250.1 68417.m03912 dihydroflavonol 4-reductase family / dihydrokaempferol... 4-reductase family similar to dihydrokaempferol 4-reductase, Ipomoea purpurea (GI:4239849), Medicago sativa, PIR2:S61416 3e-38 ...

Identification of loci Associated with Resistance to Root-Rot Diseases in Autotetraploid Alfalfa using Genome-Wide Sequencing and Association Mapping

Science.gov (United States)

Alfalfa (Medicago sativa L.) is the world-wide forage crop. Changing trends to multipurpose uses increases demand for alfalfa. However, the production of alfalfa is challenged by endemic and emerging diseases. Identification of genes/loci controlling disease resistance will facilitate breeding for i...

First report of Fusarium wilt of alfalfa caused by Fusarium oxysporum f. sp. medicaginis in Wisconsin

Science.gov (United States)

Fusarium wilt, caused by Fusarium oxysporum f. sp. medicaginis, is an economically important vascular disease of alfalfa (Medicago sativa) throughout the world. Alfalfa plants with foliar wilt symptoms and reddish-brown arcs in roots consistent with Fusarium wilt were observed in disease assessment ...

Storage characteristics, nutritive value, energy content, and in-vivo digestibility of moist large-rectangular bales of alfalfa-orchardgrass hay treated with a propionic-acid-based preservative

Science.gov (United States)

Unstable weather, poor drying conditions, and unpredictable rainfall events often place valuable hay crops at risk. Recent research with large-round bales comprised of alfalfa (Medicago sativa L.) and orchardgrass (Dactylis glomerata L.) has shown that these large-bale packages are particularly sens...

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. Copyright © 2014 Elsevier Ltd. All rights reserved.

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.

Effects of enhanced UVB on growth and yield of alfalfa (Medic ago Sativa L.) and soybean (Glycine max L.) under field conditions

International Nuclear Information System (INIS)

Al-Oudat, M.; Baydoun, S.A.; Mohamad, A.

1997-04-01

The effects of 20% increase of UVB on growth and yield of alfalfa (Medicago Sativa L.) and two cultivars of soybean (Glycine Max (L.) Mer) under field conditions have been investigated. The increase of UVB dose ranged between 1.746 and 7.112 J/cm 2 during experiment. The results showed that soybean yield decrease by 16% and 31% in A. 3803 and A. 2522 cultivars respectively, under UVB exposure. The dry weight and leaf area were sensitive in the A. 3803 cultivar, while they were tolerant in the A. 2522 cultivar. Alfalfa response to UVB varied during the different stages of growth, whereas the yield was 12% less in the exposed plants. (author). 21 refs., 17 tabs

Comparative investigation of physiological responses of field-grown ...

African Journals Online (AJOL)

An important consideration in designing and managing forage systems is the knowledge of the physiological response mechanisms to cutting, especially when water deficit conditions are prevailing. The objective of this study was to determine the physiological response of Medicago sativa and Festuca arundinacea to ...

Arabidopsis CDS blastp result: AK288497 [KOME

Lifescience Database Archive (English)

Full Text Available H3 from Zea mays SP|P05203, Medicago sativa GI:166384, Encephalartos altensteinii SP|P08903, Pisum sativum SP|P02300; contains Pfam profile PF00125 Core histone H2A/H2B/H3/H4 4e-57 ...

Molecular cloning of a novel GSK3/shaggy-like gene from Triticum ...

African Journals Online (AJOL)

The deduced amino acid sequence showed a high homology with shaggy-like kinases from Triticum aestivum, Zea mays, Trifolium repens, Nicotine tabacum, Medicago sativa and Arabidopsis thaliana; therefore, the gene was named TmGSK1 (Triticum monococcum Glycogen Synthase Kinase 1,GenBank Accession No.

Alfalfa contains substantial 9-hydroperoxide lyase activity and a 3Z:2E-enal isomerase

NARCIS (Netherlands)

Vliegenthart, J.F.G.; Noordermeer, M.A.; Veldink, G.A.

1999-01-01

Fatty acid hydroperoxides formed by lipoxygenase can be cleaved by hydroperoxide lyase resulting in the formation of short-chain aldehydes and omega-oxo acids. Plant hydroperoxide lyases use 13- or 9-hydroperoxy linoleic and linolenic acid as substrates. Alfalfa (Medicago sativa L.) has been

Forage accumulation and nutritive value of reduced lignin and reference alfalfa cultivars

Science.gov (United States)

Reduced lignin alfalfa (Medicago sativa L.) cultivars have the potential to increase the feeding value of alfalfa for livestock by improving the forage fiber digestibility and to increase harvest management flexibility. The objectives were to compare the yield and forage nutritive value of reduced ...

Enhancing pollination by attracting & retaining leaf cutting bees (Megachile rotundata) in alfalfa seed production fields

Science.gov (United States)

The alfalfa leafcutting bee, Megachile rotundata (F.), has become an important managed pollinator of alfalfa, Medicago sativa L. One problem when using alfalfa leafcutting bees as managed pollinator, is the dispersal of many females upon release, even when adequate nesting sites are present. While d...

No evidence for adaptation to local rhizobial mutualists in the legume Medicago lupulina.

Science.gov (United States)

Harrison, Tia L; Wood, Corlett W; Borges, Isabela L; Stinchcombe, John R

2017-06-01

Local adaptation is a common but not ubiquitous feature of species interactions, and understanding the circumstances under which it evolves illuminates the factors that influence adaptive population divergence. Antagonistic species interactions dominate the local adaptation literature relative to mutualistic ones, preventing an overall assessment of adaptation within interspecific interactions. Here, we tested whether the legume Medicago lupulina is adapted to the locally abundant species of mutualistic nitrogen-fixing rhizobial bacteria that vary in frequency across its eastern North American range. We reciprocally inoculated northern and southern M. lupulina genotypes with the northern ( Ensifer medicae ) or southern bacterium ( E. meliloti ) in a greenhouse experiment. Despite producing different numbers of root nodules (the structures in which the plants house the bacteria), neither northern nor southern plants produced more seeds, flowered earlier, or were more likely to flower when inoculated with their local rhizobia. We then used a pre-existing dataset to perform a genome scan for loci that showed elevated differentiation between field-collected plants that hosted different bacteria. None of the loci we identified belonged to the well-characterized suite of legume-rhizobia symbiosis genes, suggesting that the rhizobia do not drive genetic divergence between M. lupulina populations. Our results demonstrate that symbiont local adaptation has not evolved in this mutualism despite large-scale geographic variation in the identity of the interacting species.

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

Science.gov (United States)

Abirached-Darmency, Mona

2013-01-01

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 pinpoint target genes potentially involved in seed coat traits controlling final seed quality traits. The analyses revealed the complexity of the seed coat transcriptome, which contains >30 000 genes. In parallel, a set of genes showing a preferential expression in seed coat that may be involved in more specific functions was identified. The study describes how seed coat anatomy and morphological changes affect final seed quality such as seed size, seed composition, seed permeability, and hormonal regulation. Putative regulator genes of different processes have been identified as potential candidates for further functional genomic studies to improve agronomical seed traits. The study also raises new questions concerning the implication of seed coat endopolyploidy in cell expansion and the participation of the seed coat in de novo abscisic acid biosynthesis at early seed filling. PMID:23125357

High-Throughput Agrobacterium-mediated Transformation of Medicago Truncatula in Comparison to Two Expression Vectors

International Nuclear Information System (INIS)

Sultana, T.; Deeba, F.; Naqvi, S. M. S.

2016-01-01

Legumes have been turbulent to efficient Agrobacterium-mediated transformation for a long time. The selection of Medicago truncatula as a model legume plant for molecular analysis resulted in the development of efficient Agrobacterium-mediated transformation protocols. In current study, M. truncatula transformed plants expressing OsRGLP1 were obtained through GATEWAY technology using pGOsRGLP1 (pH7WG2.0=OsRGLP1). The transformation efficiency of this vector was compared with expression vector from pCAMBIA series over-expressing same gene (pCOsRGLP1). A lower number of explants generated hygromycin resistant plantlet for instance, 18.3 with pGOsRGLP1 vector as compared to 35.5 percent with pCOsRGLP1 vector. Transformation efficiency of PCR positive plants generated was 9.4 percent for pGOsRGLP1 while 21.6 percent for pCOsRGLP1. Furthermore 24.4 percent of explants generated antibiotic resistant plantlet on 20 mgl/sup -1/ of hygromycin which was higher than on 15 mgl/sup -1/ of hygromycin such as 12.2 percent. T/sub 1/ progeny analysis indicated that the transgene was inherited in Mendelian manner. The functionally active status of transgene was monitored by high level of Superoxide dismutase (SOD) activity in transformed progeny. (author)

Effects of legume species introduction on vegetation and soil nutrient development on abandoned croplands in a semi-arid environment on the Loess Plateau, China.

Science.gov (United States)

Yuan, Zi-Qiang; Yu, Kai-Liang; Epstein, Howard; Fang, Chao; Li, Jun-Ting; Liu, Qian-Qian; Liu, Xue-Wei; Gao, Wen-Juan; Li, Feng-Min

2016-01-15

Revegetation facilitated by legume species introduction has been used for soil erosion control on the Loess Plateau, China. However, it is still unclear how vegetation and soil resources develop during this restoration process, especially over the longer term. In this study, we investigated the changes of plant aboveground biomass, vegetation cover, species richness and density of all individuals, and soil total nitrogen, mineral nitrogen, total phosphorus and available phosphorus over 11 years from 2003 to 2013 in three treatments (natural revegetation, Medicago sativa L. introduction and Melilotus suaveolens L. introduction) on the semi-arid Loess Plateau. Medicago significantly increased aboveground biomass and vegetation cover, and soil total nitrogen and mineral nitrogen contents. The Medicago treatment had lower species richness and density of all individuals, lower soil moisture in the deep soil (i.e., 1.4-5m), and lower soil available phosphorus. Melilotus introduction significantly increased aboveground biomass in only the first two years, and it was not an effective approach to improve vegetation biomass and cover, and soil nutrients, especially in later stages of revegetation. Overall, our study suggests that M. sativa can be the preferred plant species for revegetation of degraded ecosystems on the Loess Plateau, although phosphorus fertilizer should be applied for the sustainability of the revegetation. Copyright © 2015 Elsevier B.V. All rights reserved.

Unraveling the involvement of ABA in the water deficit-induced modulation of nitrogen metabolism in Medicago truncatula seedlings.

Science.gov (United States)

Planchet, Elisabeth; Rannou, Olivier; Ricoult, Claudie; Limami, Anis M

2011-07-01

Effects of water deficit and/or abscisic acid (ABA) were investigated on early seedling growth of Medicago truncatula, and on glutamate metabolism under dark conditions. Water deficit (simulated by polyethylene glycol, PEG), ABA and their combination resulted in a reduction in growth rate of the embryo axis, and also in a synergistic increase of free amino acid (AA) content. However, the inhibition of water uptake retention induced by water deficit seemed to occur in an ABA-independent manner. Expression of several genes involved in glutamate metabolism was induced during water deficit, whereas ABA, in combination or not with PEG, repressed them. The only exception came from a gene encoding 1-pyrroline-5-carboxylate synthetase (P5CS) which appeared to be induced in an ABA-dependent manner under water deficit. Our results demonstrate clearly the involvement of an ABA-dependent and an ABA-independent regulatory system, governing growth and glutamate metabolism under water deficit.

Voluntary intake and digestibility by sheep of alfalfa ensiled at different moisture concentrations following fertilization with dairy slurry

Science.gov (United States)

Dairy slurry is used commonly as an animal-sourced fertilizer in agronomic production. However, residual effects of slurry application on intake and digestibility of alfalfa (Medicago sativa L.) silage from subsequent harvests are not well known. The objective of this study was to determine if mois...

Degradation of lucerne stem cell walls by five rumen bacterial species

NARCIS (Netherlands)

Jung, H.G.; Engels, F.M.; Weimer, P.J.

2004-01-01

The rumen bacterial strains Butyrivibrio fibrisolvens H17c, Fibrobacter succinogenes S85, Lachnospira multiparus 40, Ruminococcus albus 7 and R. flavefaciens FD-1 were compared individually and as a five-species mixture with a rumen inoculum for their ability to degrade lucerne (Medicago sativa L.)

Meat goat kids finished on alfalfa, red clover, or orchardgrass pastures: Carcass merit and meat quality

Science.gov (United States)

This experiment was conducted in 2005-2007 to evaluate carcass and meat quality parameters when meat goat kids were finished on alfalfa (Medicago sativa L; ALF); red clover (Trifolium pretense L.; RCG); or orchardgrass (Dactylis glomerata L; OGR) pastures. Final shrunk body weights were similar whe...

Development and characterization of the first infectious clone of alfalfa latent virus, a strain of Pea streak virus

Science.gov (United States)

Alfalfa (Medicago sativa) is a natural host plant for many plant pathogens including fungi, bacteria, nematodes and viruses. Alfalfa latent virus (ALV) is a member of the carlavirus group and occurs symptomlessly in alfalfa. The first complete genomic sequence of the ALV that was recently obtained i...

[Molecular identification of astragali radix and its adulterants by ITS sequences].

Science.gov (United States)

Cui, Zhan-Hu; Li, Yue; Yuan, Qing-Jun; Zhou, Li-She; Li, Min-Hui

2012-12-01

To explore a new method for identification Astragali Radix from its adulterants by using ITS sequence. Thirteen samples of the different Astragali Radix materials and 6 samples of the adulterants of the roots of Hedysarum polybotrys, Medicago sativa and Althaea rosea were collected. ITS sequence was amplified by PCR and sequenced unidirectionally. The interspecific K-2-P distances of Astragali Radix and its adulterants were calculated, and NJ tree and UPGMA tree were constructed by MEGA 4. ITS sequences were obtained from 19 samples respectively, there were Astragali Radix 646-650 bp, H. polybotrys 664 bp, Medicago sativa 659 bp, Althaea rosea 728 bp, which were registered in the GenBank. Phylogeny trees reconstruction using NJ and UPGMA analysis based on ITS nucleotide sequences can effectively distinguish Astragali Radix from adulterants. ITS sequence can be used to identify Astragali Radix from its adulterants successfully and is an efficient molecular marker for authentication of Astragali Radix and its adulterants.

Experimental tolerance to boron of the plant species Nicotiana glauca, Jacaranda mimosifolia, Tecoma stans, Medicago sativa y Spinacea oleracea in Argentina; Tolerancia experimental de las especies vegetales Nicotiana glauca, Jacaranda mimosifolia, Tecoma stans, Medicago sativa y Spinacea oleracea al boro, en Argentina

Energy Technology Data Exchange (ETDEWEB)

Viana, Marta L. de; Albarracin Franco, Silvia [Univ. Nacional de Salta, Inst. de Ecologia y Ambiente Humano, CIUNSa, Buenos Aires No. 177, 4400, Salta (Argentina)], E-mail: mldeviana@arnet.com.ar

2008-09-15

The activity of the borate deposits industries constitutes a point source and diffuse pollution of air, soil and water. Therefore, the study and experimentation on possible ways to offset this impact is a priority. A relatively new technique to decontaminate soils is phytoremediation, which uses plants and associated microorganisms. The first step is to identify tolerant plant species, which is the focus of this work. An experiment was conducted in the laboratory to evaluate the germination, survival and growth of different species in different concentrations of boron. At the beginning and end of the experiment was determined concentration of boron in the substrate for each treatment and for substrates with and without vegetation. Significant differences due to treatment, the species and species-treatment interaction. M. sativa, N. glauca and J. mimosifolia were the species most tolerant to boron. The other species showed a decrease in all variables-response function of the concentration of the contaminant. All had low survival in the highest concentration. The decrease of boron was highest in the treatment of 30 ppm of boron with M. sativa and the lowest was recorded in the treatment of 20 ppm of boron with J. mimosifolia and 30 ppm of boron with T. stans and S. oleracea. It is concluded that N. glauca, M. sativa and J. mimosifolia could be considered as promising remediation. (author) [Spanish] La actividad de las industrias borateras constituye una fuente puntual y difusa de contaminacion del aire, suelo y aguas superficiales y profundas. Por lo tanto, el estudio y experimentacion acerca de las posibles formas de contrarrestar este impacto constituye una prioridad. Una tecnica relativamente nueva para descontaminar suelos es la fitorremediacion, que emplea plantas y microorganismos asociados. El primer paso es detectar las especies vegetales tolerantes, lo que constituye el objetivo de este trabajo. Se realizo un experimento en laboratorio para evaluar la

Changes in mycorrhiza development in maize induced by crop management practices

DEFF Research Database (Denmark)

Gavito, M.E.; Miller, M.H.

1998-01-01

(Zea mays L.) or with the original plant species in the field site, bromegrass (Bromus inermis Leys.) and alfalfa (Medicago sativa L.). The delay in mycorrhiza development after cropping with canola was also observed in samples taken from the field and in a bioassay, both conducted at the beginning...

Reduced Lignin Alfalfa - Update

Science.gov (United States)

U.S. farmers harvested alfalfa (Medicago sativa) for hay or haylage from 24.5million acres in 2009. Midwestern states harvested 57 % of 2009 acreage for hay and haylage. However, acreage is stable to declining. Alfalfa provides an excellent source of fiber, protein, minerals and vitamins that partia...

Mechanisms of qualitative and quantitative resistance to Aphanomyces root rot in alfalfa

Science.gov (United States)

Aphanomyces root rot (ARR), caused by Aphanomyces euteiches, is one of the most important diseases of alfalfa (Medicago sativa) in the United States. Two races of the pathogen are currently recognized. Most modern alfalfa cultivars have high levels of resistance to race 1 but few cultivars have resi...

Dynamics of predation on Lygus hesperus (Hemiptera: Miridae) in alfalfa trap cropped organic strawberry

Science.gov (United States)

Alfalfa (Medicago sativa L.) can be strategically planted as a trap crop for Lygus spp. in California’s organic strawberry fields. Alfalfa has been shown to attract both Lygus spp. and, in turn, a Lygus-specific parasitoid, Peristenus relictus (Ruthe). However, the impact of alfalfa trap-cropped st...

Establishing vegetation on Kimberlite mine tailings: 2. Field trials. | N ...

African Journals Online (AJOL)

A series of field experiments were carried out on Kimberlite mine tailing located at Cullinan in the Transvaal. The most successful species in pure sward were Chloris gayana, Cynodon aethiopicus, Eragrostis curvula, E. tef, Pennisetum purpureum, Melilotus alban and Medicago sativa. Growth of grasses in the absence of ...

Cover crops for managing weeds, soil chemical fertility and nutritional status of organically grown orange orchard in Sicily

Directory of Open Access Journals (Sweden)

Rosario Paolo Mauro

2015-06-01

Full Text Available Cover crops can offer significant advantages in the agronomic management of citrus orchards in Mediterranean environments. Therefore, a three-year research was conducted in eastern Sicily aimed at studying the effects of four cover crop sequences (Sinapis arvensis-Trigonella foenum-graecum-T. foenum-graecum; Medicago scutellata-Avena sativa-Lolium perenne; Vicia faba minor-A. sativa-A. sativa; A. sativa-V. faba. minor-L. perenne on weeds, major soil chemical properties and nutritional status of an organically grown orange orchard. The results highlighted that, among the studied cover crop sequences, Vicia faba-Avena-Avena was the most beneficial for weeds control within the orchard (92%, of cover crop cover, and 586 and 89 g DW m–2 of cover crop aboveground biomass and weeds aboveground biomass, respectively. Overall, the chemical fertility of the soil was positively influenced. In particular, it was observed an increase of the content of total nitrogen and available phosphorus in the soil by both Sinapis-Trigonella-Trigonella (0.75 g kg–1 and 59.0 mg kg–1, respectively and Vicia faba-Avena-Avena (0.70 g kg–1 and 56.0 mg kg–1, respectively cover crop sequences. Medicago-Avena-Lolium sequence seemed to be the most useful to ensure a better nutritional status of the orange orchard.

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

Energy Technology Data Exchange (ETDEWEB)

Dauzart, Ariel J. C.; Vandenbrink, Joshua P.; Kiss, John Z., E-mail: jzkiss@olemiss.edu [Department of Biology, Graduate School, University of Mississippi, University, MS (United States)

2016-02-26

Understanding the outcome of the plant-microbe symbiosis in reduced or altered 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.

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

International Nuclear Information System (INIS)

Dauzart, Ariel J. C.; Vandenbrink, Joshua P.; Kiss, John Z.

2016-01-01

Understanding the outcome of the plant-microbe symbiosis in reduced or altered 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.

Taxonomy Icon Data: barrel medic [Taxonomy Icon

Lifescience Database Archive (English)

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The long-term effects of alfalfa on soil water content in the Loess ...

African Journals Online (AJOL)

Administrator

2011-05-23

May 23, 2011 ... affect the water content in deep soil and continuous growing alfalfa ... Wasteland, wheat field and six seeded alfalfa (Medicago sativa L.) grasslands with ... The crops (wheat, maize, potato, beans and millet) had been rainfed on all ..... Productivity dynamic of alfalfa and its effects on water eco-environment.

Effects of a propionic acid-based preservative on storage characteristics, nutritive value, and energy content for alfalfa hays packaged in large, round bales

Science.gov (United States)

During 2009 and 2010, alfalfa (Medicago sativa L.) hays from two cuttings that were harvested from the same field site were used to evaluate the effects of a propionic acid-based preservative on the storage characteristics and nutritive value of hays stored as large, round bales. A total of 87 large...

Do soil tests help forecast nitrogen response in first-year corn following alfalfa on fine-textured soils?

Science.gov (United States)

Improved methods of predicting grain yield response to fertilizer N for first-year corn (Zea mays L.) following alfalfa (Medicago sativa L.) on fine-textured soils are needed. Data from 21 site-years in the North Central Region were used to (i) determine how Illinois soil nitrogen test (ISNT) and pr...

Caesium inhibits the colonization of Medicago truncatula by arbuscular mycorrhizal fungi

International Nuclear Information System (INIS)

Wiesel, Lea; Dubchak, Sergiy; Turnau, Katarzyna; Broadley, Martin R.; White, Philip J.

2015-01-01

Contamination of soils with radioisotopes of caesium (Cs) is of concern because of their emissions of harmful β and γ radiation. Radiocaesium enters the food chain through vegetation and the intake of Cs can affect the health of organisms. Arbuscular mycorrhizal (AM) fungi form mutualistic symbioses with plants through colonization of the roots and previous studies on the influence of AM on Cs concentrations in plants have given inconsistent results. These studies did not investigate the influence of Cs on AM fungi and it is therefore not known if Cs has a direct effect on AM colonization. Here, we investigated whether Cs influences AM colonization and if this effect impacts on the influence of Rhizophagus intraradices on Cs accumulation by Medicago truncatula. M. truncatula was grown with or without R. intraradices in pots containing different concentrations of Cs. Here, we present the first evidence that colonization of plants by AM fungi can be negatively affected by increasing Cs concentrations in the soil. Mycorrhizal colonization had little effect on root or shoot Cs concentrations. In conclusion, the colonization by AM fungi is impaired by high Cs concentrations and this direct effect of soil Cs on AM colonization might explain the inconsistent results reported in literature that have shown increased, decreased or unaffected Cs concentrations in AM plants. - Highlights: • Colonization of plants by arbuscular mycorrhizal fungi is negatively affected by increasing soil caesium concentrations. • Shoot caesium concentrations are not influenced by AM fungi at soil caesium concentrations above about 3 μg Cs kg −1 . • The direct effect of caesium on AM fungi might impact on the influence of AM fungi on Cs accumulation in plants. • This might explain the inconsistent results reported in literature on Cs accumulation in AM plants

The ecological genomic basis of salinity adaptation in Tunisian Medicago truncatula.

Science.gov (United States)

Friesen, Maren L; von Wettberg, Eric J B; Badri, Mounawer; Moriuchi, Ken S; Barhoumi, Fathi; Chang, Peter L; Cuellar-Ortiz, Sonia; Cordeiro, Matilde A; Vu, Wendy T; Arraouadi, Soumaya; Djébali, Naceur; Zribi, Kais; Badri, Yazid; Porter, Stephanie S; Aouani, Mohammed Elarbi; Cook, Douglas R; Strauss, Sharon Y; Nuzhdin, Sergey V

2014-12-22

As our world becomes warmer, agriculture is increasingly impacted by rising soil salinity and understanding plant adaptation to salt stress can help enable effective crop breeding. Salt tolerance is a complex plant phenotype and we know little about the pathways utilized by naturally tolerant plants. Legumes are important species in agricultural and natural ecosystems, since they engage in symbiotic nitrogen-fixation, but are especially vulnerable to salinity stress. Our studies of the model legume Medicago truncatula in field and greenhouse settings demonstrate that Tunisian populations are locally adapted to saline soils at the metapopulation level and that saline origin genotypes are less impacted by salt than non-saline origin genotypes; these populations thus likely contain adaptively diverged alleles. Whole genome resequencing of 39 wild accessions reveals ongoing migration and candidate genomic regions that assort non-randomly with soil salinity. Consistent with natural selection acting at these sites, saline alleles are typically rare in the range-wide species' gene pool and are also typically derived relative to the sister species M. littoralis. Candidate regions for adaptation contain genes that regulate physiological acclimation to salt stress, such as abscisic acid and jasmonic acid signaling, including a novel salt-tolerance candidate orthologous to the uncharacterized gene AtCIPK21. Unexpectedly, these regions also contain biotic stress genes and flowering time pathway genes. We show that flowering time is differentiated between saline and non-saline populations and may allow salt stress escape. This work nominates multiple potential pathways of adaptation to naturally stressful environments in a model legume. These candidates point to the importance of both tolerance and avoidance in natural legume populations. We have uncovered several promising targets that could be used to breed for enhanced salt tolerance in crop legumes to enhance food security

Environmental regulation of lateral root emergence in Medicago truncatula requires the HD-Zip I transcription factor HB1.

Science.gov (United States)

Ariel, Federico; Diet, Anouck; Verdenaud, Marion; Gruber, Véronique; Frugier, Florian; Chan, Raquel; Crespi, Martin

2010-07-01

The adaptation of root architecture to environmental constraints is a major agricultural trait, notably in legumes, the third main crop worldwide. This root developmental plasticity depends on the formation of lateral roots (LRs) emerging from primary roots. In the model legume Medicago truncatula, the HD-Zip I transcription factor HB1 is expressed in primary and lateral root meristems and induced by salt stress. Constitutive expression of HB1 in M. truncatula roots alters their architecture, whereas hb1 TILLING mutants showed increased lateral root emergence. Electrophoretic mobility shift assay, promoter mutagenesis, and chromatin immunoprecipitation-PCR assays revealed that HB1 directly recognizes a CAATAATTG cis-element present in the promoter of a LOB-like (for Lateral Organ Boundaries) gene, LBD1, transcriptionally regulated by auxin. Expression of these genes in response to abscisic acid and auxin and their behavior in hb1 mutants revealed an HB1-mediated repression of LBD1 acting during LR emergence. M. truncatula HB1 regulates an adaptive developmental response to minimize the root surface exposed to adverse environmental stresses.

Medicago truncatula Gaertn. as a model for understanding the mechanism of growth promotion by bacteria from rhizosphere and nodules of alfalfa.

Science.gov (United States)

Kisiel, Anna; Kępczyńska, Ewa

2016-05-01

The present study showed all the 16 strains isolated and identified from the alfalfa rhizosphere and nodules, and registered in GenBank, to be good candidates for targeted use in studies addressing the rather weak known mechanism of plant growth promotion, including that of Medicago truncatula, a molecular crop model. Based on physiological, biochemical and molecular analysis, the 16 isolates obtained were ascribed to the following five families: Bacillaceae, Rhizobiaceae, Xantomonadaceae, Enterobacteriaceae and Pseudomonadaceae, within which 9 genera and 16 species were identified. All these bacteria were found to significantly enhance fresh and dry weight of root, shoots and whole 5-week-old seedlings. The bacteria were capable of the in vitro use of tryptophan to produce indolic compounds at various concentrations. The ability of almost all the strains to enhance growth of seedlings and individual roots was positively correlated with the production of the indolic compounds (r = 0.69; P = 0.0001), but not with the 1-aminocyclopropane-1-carboxylate deaminase (ACCD) activity (no correlation). For some strains, it was difficult to conclude whether the growth promotion was related to the production of indolic compounds or to the ACCD activity. It is likely that promotion of M. truncatula root development involves also root interaction with pseudomonads, known to produce 2,4-diacetylphloroglucinol (DAPG), a secondary metabolite reported to alter the root architecture by interacting with an auxin-dependent signaling pathway. Inoculation of seedlings with Pseudomonas brassicacearum KK 5, a bacterium known for its lowest ability to produce indolic compounds, the highest ACCD activity and the presence of the phlD gene responsible for DAPG precursor synthesis, resulted in a substantial promotion of root development. Inoculation with the strain increased the endogenous IAA level in M. truncatula leaves after inoculation of 5-week-old seedlings. Three other strains examined

Study of the boron distribution in pea and alfalfa plants using SSNTD

International Nuclear Information System (INIS)

Li Jianming; Inst. for Application of Atomic Energy)" data-affiliation=" (Chinese Academy of Agricultural Sciences, Beijing, BJ (China)> Inst. for Application of Atomic Energy)" >Deng Hongmin

1988-01-01

The distribution of boron in pea (Pisum sativum L.) and alfalfa (Medicago sativa L.) was determined by using SSNTD. The results show that boron concentrations in leaves are highest, furthermore boron concentrations of the base leaves are higher than those of the top leaves. Among flower tissues, calyx has the highest boron concentration

Prohexadione-calcium rate and timing effects on alfalfa interseeded into silage corn

Science.gov (United States)

Prohexadione-Ca (PHD) can enhance establishment of alfalfa (Medicago sativa, L.) interseeded into silage corn (Zea mays, L.), but optimal application rates and timing for this growth regulator are unknown. Two experiments examined how single or split applications of 0.25 to 1.0 kg a.i. ha-1 of PHD o...

Calcium ion binding properties of Medicago truncatula calcium/calmodulin-dependent protein kinase.

Science.gov (United States)

Swainsbury, David J K; Zhou, Liang; Oldroyd, Giles E D; Bornemann, Stephen

2012-09-04

A calcium/calmodulin-dependent protein kinase (CCaMK) is essential in the interpretation of calcium oscillations in plant root cells for the establishment of symbiotic relationships with rhizobia and mycorrhizal fungi. Some of its properties have been studied in detail, but its calcium ion binding properties and subsequent conformational change have not. A biophysical approach was taken with constructs comprising either the visinin-like domain of Medicago truncatula CCaMK, which contains EF-hand motifs, or this domain together with the autoinhibitory domain. The visinin-like domain binds three calcium ions, leading to a conformational change involving the exposure of hydrophobic surfaces and a change in tertiary but not net secondary or quaternary structure. The affinity for calcium ions of visinin-like domain EF-hands 1 and 2 (K(d) = 200 ± 50 nM) was appropriate for the interpretation of calcium oscillations (~125-850 nM), while that of EF-hand 3 (K(d) ≤ 20 nM) implied occupancy at basal calcium ion levels. Calcium dissociation rate constants were determined for the visinin-like domain of CCaMK, M. truncatula calmodulin 1, and the complex between these two proteins (the slowest of which was 0.123 ± 0.002 s(-1)), suggesting the corresponding calcium association rate constants were at or near the diffusion-limited rate. In addition, the dissociation of calmodulin from the protein complex was shown to be on the same time scale as the dissociation of calcium ions. These observations suggest that the formation and dissociation of the complex between calmodulin and CCaMK would substantially mirror calcium oscillations, which typically have a 90 s periodicity.

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.

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

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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.

Evaluation of Atriplex halimus, Medicago lupulina and Portulaca oleracea for phytoremediation of Ni, Pb, and Zn.

Science.gov (United States)

Amer, Nasser; Al Chami, Ziad; Al Bitar, Lina; Mondelli, Donato; Dumontet, Stefano

2013-01-01

Suitable plant species are able to accumulate heavy metals and to produce biomass useful for non-food purposes. In this study, three endemic Mediterranean plant species, Atriplex halimus, Portulaca oleracea and Medicago lupulina were grown hydroponically to assess their potential use in phytoremediation and biomass production. The experiment was carried out in a growth chamber using half strength Hoagland's solutions separately spiked with 5 concentrations of Pb and Zn (5, 10, 25, 50, and 100 mg L(-1)), and 3 concentrations of Ni (1, 2 and 5 mg L(-1)). Shoot and root biomass were determined and analyzed for their metals contents. A. halimus and M. lupulina gave high shoot biomass with relatively low metal translocation to the above ground parts. Metals uptake was a function of both metals and plant species. It is worth noting that M. lupulina was the only tested plant able to grow in treatment Pb50 and to accumulate significant amount of metal in roots. Plant metal uptake efficiency ranked as follows: A. halimus > M. lupulina > P. oleracea. Due to its high biomass production and the relatively high roots metal contents, A. halimus and M. lupulina could be successfully used in phytoremediation, and in phytostabilization, in particular.

Effect of drought and rewatering on the cellular status and antioxidant response of Medicago truncatula plants.

Science.gov (United States)

Filippou, Panagiota; Antoniou, Chrystalla; Fotopoulos, Vasileios

2011-02-01

Effects of water stress on plants have been well-documented. However, the combined responses to drought and rewatering and their underlying mechanisms are relatively unknown. The present study attempts to describe spatiotemporal alterations in the physiology and cellular status of Medicago truncatula tissues that result from and subsequently follow a period of moderate water deficit. Physiological processes and cellular damage levels were monitored in roots and leaves by determining lipid peroxidation levels, as well as nitric oxide and hydrogen peroxide content, further supported by stomatal conductance and chlorophyll fluorescence measurements in leaves. During water stress, cells in both organs displayed increased damage levels and reactive oxygen and nitrogen species content, while leaves showed reduced stomatal conductance. Furthermore, both tissues demonstrated increased proline content. Upon rewatering, plants recovered displaying readings similar to pre-stress control conditions. Furthermore, molecular analysis of antioxidant gene expression by quantitative real-time RT-PCR revealed differential spatiotemporal regulation in a number of genes examined (including catalase, cytosolic ascorbate peroxidase, copper/zinc and iron superoxide dismutase and alternative oxidase). Overall, M. truncatula plants demonstrated increased sensitivity to drought-induced oxidative damage; however, this was reversed following rewatering indicating a great elasticity in the plant's capacity to cope with free oxygen radicals. 

Co-invading symbiotic mutualists of Medicago polymorpha retain high ancestral diversity and contain diverse accessory genomes.

Science.gov (United States)

Porter, Stephanie S; Faber-Hammond, Joshua J; Friesen, Maren L

2018-01-01

Exotic, invasive plants and animals can wreak havoc on ecosystems by displacing natives and altering environmental conditions. However, much less is known about the identities or evolutionary dynamics of the symbiotic microbes that accompany invasive species. Most leguminous plants rely upon symbiotic rhizobium bacteria to fix nitrogen and are incapable of colonizing areas devoid of compatible rhizobia. We compare the genomes of symbiotic rhizobia in a portion of the legume's invaded range with those of the rhizobium symbionts from across the legume's native range. We show that in an area of California the legume Medicago polymorpha has invaded, its Ensifer medicae symbionts: (i) exhibit genome-wide patterns of relatedness that together with historical evidence support host-symbiont co-invasion from Europe into California, (ii) exhibit population genomic patterns consistent with the introduction of the majority of deep diversity from the native range, rather than a genetic bottleneck during colonization of California and (iii) harbor a large set of accessory genes uniquely enriched in binding functions, which could play a role in habitat invasion. Examining microbial symbiont genome dynamics during biological invasions is critical for assessing host-symbiont co-invasions whereby microbial symbiont range expansion underlies plant and animal invasions. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Soil sulfur amendments suppress Selenium uptake by alfalfa and western wheatgrass

Science.gov (United States)

C. L. Mackowiak; M. C. Amacher

2008-01-01

Selenium (Se) is a potential soil contaminant in many parts of the world where it can pose a health risk to livestock and wildlife. Phosphate ore mining in Southeast Idaho has resulted in numerous waste rock dumps revegetated with forages to stabilize the dumps and support grazing. Alfalfa (Medicago sativa L.), smooth brome (Bromus inermis...

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.

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.

Impacto de una intervención alimentaria con un concentrado proteico de Medicago sativa L (alfalfa, en niños pre escolares con desnutrición crónica

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María Soberón

2009-09-01

Full Text Available Introducción: Estudios realizados a nivel preclínico han demostrado el valor biológico del concentrado proteico obtenido de Medicago sativa L, alfalfa (CPA, por lo que este producto puede ser una alternativa para reducir la desnutrición. Objetivo: Evaluar el efecto del consumo de CPA por niños preescolares con desnutrición crónica, mediante indicadores bioquímicos y hematológicos. Diseño: Estudio analítico de intervención, de tipo longitudinal y prospectivo. Institución: Centro de Investigación de Bioquímica y Nutrición, Facultad de Medicina, Universidad Nacional Mayor de San Marcos. Participantes: Niños preescolares con desnutrición crónica, provenientes de una comunidad de Pampas, Huancavelica, Perú. Intervenciones: Previo consentimiento informado de los padres, se evaluó el estado alimentario-nutricional, bioquímico y hematológico de 23 niños menores de seis años, para establecer la condición de desnutrición. Luego, se desarrolló una intervención alimentario nutricional con el CPA como complemento alimenticio, por 25 días, en niños seleccionados. Finalmente, se repitió la evaluación una vez concluido el período de intervención. Las determinaciones bioquímicas fueron hemoglobina, proteínas totales, albúmina y globulina, creatinina, transaminasas, y las hematológicas, hematocrito, recuento de reticulocitos. Se utilizó el programa Excel y t-student, a fin de obtener la inferencia en los resultados. Resultados: Para el indicador talla/edad, 84,5% de los niños padecía desnutrición crónica; respecto a calorías y nutrientes consumidos por los niños, los valores de energía estuvieron entre 563 kcal y 2 597 kcal; de proteína, 9,7 g a 78 g; de grasas, 5,1 g a 53,8 g; carbohidratos, 79,8 g a 495,1 g; calcio, entre 180,9 mg y 986 mg; y hierro, 1,9 mg y 21,5 mg. Los valores de hemoglobina, proteínas totales, globulinas, creatinina, transaminasas y hematocrito obtenidos antes y después de la ingesta de

Design of optimal solvent for extraction of bio–active ingredients from six varieties of Medicago sativa

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Caunii Angela

2012-10-01

Full Text Available Abstract Background Extensive research has been performed worldwide and important evidences were collected to show the immense potential of plants used in various traditional therapeutic systems. The aim of this work is to investigate the different extracting solvents in terms of the influence of their polarity on the extracting ability of bioactive molecules (phenolic compounds from the M. sativa flowers. Results The total phenolic content of samples was determined using the Folin Ciocalteu (FC procedure and their antioxidant activity was assayed through in vitro radical decomposing activity using the radical DPPH° assay (IUPAC name for DPPH is (phenyl–(2,4,6–trinitrophenyl iminoazanium. The results showed that water was better than methanol and acetic acid for extracting bioactive compounds, in particular for total phenolic compounds from the flowers of alfalfa. The average content of bioactive molecules in methanol extract was 263.5±1.02 mg GAE/100g of dry weight lyophilized extract. The total phenolic content of the tested plant extracts was highly correlated with the radical decomposing activity. However, all extracts were free–radical inhibitors, but the water extract was more potent than the acetic and the methanol ones. The order of inhibitor effectiveness (expressed by IC50 proved to be: water extract (0.924mg/mL > acetic acid extract (0.154mg/mL > methanol (0.079mg/mL. The profiles of each extract (fingerprint were characterized by FT–MIR spectroscopy. Conclusions The present study compares the fingerprint of different extracts of the M. sativa flowers, collected from the wild flora of Romania. The total phenolic content of the tested plant extracts was highly correlated with the radical decomposing activity. The dependence of the extract composition on the solvent polarity (acetic acid vs. methanol vs. water was revealed by UV–VIS spectrometry and Infrared fingerprint.

Monterey Peninsula Water Supply Project Supplemental Draft Environmental Impact Report/Statement. Appendices. Monterey Peninsula Water Management District

Science.gov (United States)

1991-08-01

device and trapping facility near the face cf the 8 3 88089 A3-7 FIGURE 3-3 -7/ .7-U mv I 1 . - a Cach agua Creek Site Are a V 0 2.5 5 I I 1L KilometersI...succulentus succulent annual lupine Madia gracilis gumweed Madia madioides woodland madia Madia sativa Chile tarweed Marah fabaceus manroot Medicago...Lupinus nanus ssp. nanus sky lupine Lupinus succulentus succulent annual lupine Madia gracilis gumweed Madia sativa Chile tarweed I Marah fabaceus

Effects of cutting frequency on alfalfa yield and yield components in ...

African Journals Online (AJOL)

Effects of cutting frequency on alfalfa yield and yield components in Songnen Plain, Northeast China. J Chen, F Tang, R Zhu, C Gao, G Di, Y Zhang. Abstract. The productivity and quality of alfalfa (Medicago sativa L.) is strongly influenced by cutting frequency (F). To clarify that the yield and quality of alfalfa if affected by F, ...

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

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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

Genetic Engineering of Alfalfa (Medicago sativa L.).

Science.gov (United States)

Wang, Dan; Khurshid, Muhammad; Sun, Zhan Min; Tang, Yi Xiong; Zhou, Mei Liang; Wu, Yan Min

2016-01-01

Alfalfa is excellent perennial legume forage for its extensive ecological adaptability, high nutrition value, palatability and biological nitrogen fixation. It plays a very important role in the agriculture, animal husbandry and ecological construction. It is cultivated in all continents. With the development of modern plant breeding and genetic engineering techniques, a large amount of work has been carried out on alfalfa. Here we summarize the recent research advances in genetic engineering of alfalfa breeding, including transformation, quality improvement, stress resistance and as a bioreactor. The review article can enables us to understand the research method, direction and achievements of genetic engineering technology of Alfalfa.

Regulatory patterns of a large family of defensin-like genes expressed in nodules of Medicago truncatula.

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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.

Manejo de água para estabelecimento de alfafa (Medicago sativa L. Water management for alfalfa (Medicago sativa L. establishment

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Joaquim Bartolomeu Rassini

2001-04-01

Full Text Available O manejo de água para o desenvolvimento da alfafa cv. Crioula foi avaliado a campo, com a finalidade de verificar seus efeitos no estabelecimento da planta, até o 1º corte, em 1997. Para isso, verificou-se o comportamento em três estádios de desenvolvimento (E1 = início do estádio vegetativo, E2 = vegetativo pleno e E3 = reprodutivo até colheita em quatro níveis de água (A = 100%, B = 80%, C = 45-50% e D = 20-25% de uma lâmina de irrigação por aspersão. Foram avaliados oito experimentos: 111, 110, 100, 101, 001, 011, 010, 000, em que o primeiro dígito se refere a E1; o segundo, a E2; e o terceiro, a E3. O valor 0 representa a época em que o estádio não recebeu água, coberto por uma estrututura móvel, que deslizava sobre trilhos, e também protegia contra precipitações pluviais casuais. O valor 1 refere-se à época em que houve aplicação dos níveis de água de irrigação. Os estádios de desenvolvimento da planta, em termos de rendimento de matéria seca, responderam de maneira diferente às condições hídricas, sendo E2 e E3 (planta estabelecida os mais sensíveis e E1 (início do estádio vegetativo, o menos sensível, no qual a água foi prejudicial ao estabelecimento e rendimento da planta.The water management for growth of Crioula alfalfa cultivar was evaluated in a field study, in order to assess the effects in the plant establishment up to the first cut, at 1977. The study was carried out in 1997. So that, the behaviour at three growth stages (E1 = early vegetative stage, E2 = full vegetative stage, and E3 = reproductive stage until harvest in the presence of four water levels (A = 100%, B = 80%, C = 45-50%, and D = 20-25% from a sprinkler irrigation was studied. Eight combinations were evaluated: 111, 110, 100, 101, 001, 011, 010, 000, where the first digit is E1, the second is E2 and the third is E3. The number 0 in the figures represents the period in which growth stage did not receive water, cover by a mobile structure, which slide on trail, and also protected against occasional rainfall. The number 1 represents the time in which the irrigation water levels were applied. The growth stages of the plants as for dry matter yield, differently respond to the water conditions. The E2 and E3 were the most sensible to water supply and E1 the least sensible; in which the water was detrimental to the plant establishment and yield.

The Medicago truncatula GRAS protein RAD1 supports arbuscular mycorrhiza symbiosis and Phytophthora palmivora susceptibility.

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Rey, Thomas; Bonhomme, Maxime; Chatterjee, Abhishek; Gavrin, Aleksandr; Toulotte, Justine; Yang, Weibing; André, Olivier; Jacquet, Christophe; Schornack, Sebastian

2017-12-16

The roots of most land plants are colonized by symbiotic arbuscular mycorrhiza (AM) fungi. To facilitate this symbiosis, plant genomes encode a set of genes required for microbial perception and accommodation. However, the extent to which infection by filamentous root pathogens also relies on some of these genes remains an open question. Here, we used genome-wide association mapping to identify genes contributing to colonization of Medicago truncatula roots by the pathogenic oomycete Phytophthora palmivora. Single-nucleotide polymorphism (SNP) markers most significantly associated with plant colonization response were identified upstream of RAD1, which encodes a GRAS transcription regulator first negatively implicated in root nodule symbiosis and recently identified as a positive regulator of AM symbiosis. RAD1 transcript levels are up-regulated both in response to AM fungus and, to a lower extent, in infected tissues by P. palmivora where its expression is restricted to root cortex cells proximal to pathogen hyphae. Reverse genetics showed that reduction of RAD1 transcript levels as well as a rad1 mutant are impaired in their full colonization by AM fungi as well as by P. palmivora. Thus, the importance of RAD1 extends beyond symbiotic interactions, suggesting a general involvement in M. truncatula microbe-induced root development and interactions with unrelated beneficial and detrimental filamentous microbes. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

The arbuscular mycorrhizal fungus Glomus mosseae can enhance arsenic tolerance in Medicago truncatula by increasing plant phosphorus status and restricting arsenate uptake

International Nuclear Information System (INIS)

Xu Pengliang; Christie, Peter; Liu Yu; Zhang Junling; Li Xiaolin

2008-01-01

A pot experiment examined the biomass and As uptake of Medicago truncatula colonized by the arbuscular mycorrhizal (AM) fungus Glomus mosseae in low-P soil experimentally contaminated with different levels of arsenate. The biomass of G. mosseae external mycelium was unaffected by the highest addition level of As studied (200 mg kg -1 ) but shoot and root biomass declined in both mycorrhizal and non-mycorrhizal plants, indicating that the AM fungus was more tolerant than M. truncatula to arsenate. Mycorrhizal inoculation increased shoot and root dry weights by enhancing host plant P nutrition and lowering shoot and root As concentrations compared with uninoculated plants. The AM fungus may have been highly tolerant to As and conferred enhanced tolerance to arsenate on the host plant by enhancing P nutrition and restricting root As uptake. - G. mosseae was more tolerant than M. truncatula to As and may have conferred enhanced host tolerance by restricting root As uptake and enhancing P nutrition

The arbuscular mycorrhizal fungus Glomus mosseae can enhance arsenic tolerance in Medicago truncatula by increasing plant phosphorus status and restricting arsenate uptake

Energy Technology Data Exchange (ETDEWEB)

Xu Pengliang [Key Laboratory of Plant-Soil Interactions, Ministry of Education, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100094 (China); Christie, Peter [Key Laboratory of Plant-Soil Interactions, Ministry of Education, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100094 (China); Agricultural and Environmental Science Department, Queen' s University Belfast, Belfast BT9 5PX (United Kingdom); Liu Yu [Key Laboratory of Plant-Soil Interactions, Ministry of Education, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100094 (China); Zhang Junling [Key Laboratory of Plant-Soil Interactions, Ministry of Education, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100094 (China)], E-mail: junlingz@cau.edu.cn; Li Xiaolin [Key Laboratory of Plant-Soil Interactions, Ministry of Education, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100094 (China)

2008-11-15

A pot experiment examined the biomass and As uptake of Medicago truncatula colonized by the arbuscular mycorrhizal (AM) fungus Glomus mosseae in low-P soil experimentally contaminated with different levels of arsenate. The biomass of G. mosseae external mycelium was unaffected by the highest addition level of As studied (200 mg kg{sup -1}) but shoot and root biomass declined in both mycorrhizal and non-mycorrhizal plants, indicating that the AM fungus was more tolerant than M. truncatula to arsenate. Mycorrhizal inoculation increased shoot and root dry weights by enhancing host plant P nutrition and lowering shoot and root As concentrations compared with uninoculated plants. The AM fungus may have been highly tolerant to As and conferred enhanced tolerance to arsenate on the host plant by enhancing P nutrition and restricting root As uptake. - G. mosseae was more tolerant than M. truncatula to As and may have conferred enhanced host tolerance by restricting root As uptake and enhancing P nutrition.

Symbiotic N2 fixation by legumes growing in pots. 2. Uptake of VN-labelled NO3 , C2H2 reduction and H2 evolution by Trifolium subterraneum L. , Medicago truncatula Gaertn. and Acacia dealbata Link

Energy Technology Data Exchange (ETDEWEB)

Hopmans, P.; Chalk, P.M.; Douglas, L.A.

1983-01-01

The objectives of this study were to estimate symbiotic nitrogen fixation by two common pasture legumes, Trifolium subterraneum L. and Medicago truncatula Gaertn., and an Australian native legume, Acacia dealbata Link, growing in pots using an indirect isotopic method. This method was also used to calibrate the C2H2 reduction assay of the intact plants. In addition, hydrogen evolution was measured in an attempt to explain the variations in C2H2:N2 ratios between the species. 25 refs.; 1 figure; 4 tabs.

Cloning and characterization of a heme oxygenase-2 gene from alfalfa (Medicago sativa L.).

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Fu, Guang-Qing; Jin, Qi-Jiang; Lin, Yu-Ting; Feng, Jian-Fei; Nie, Li; Shen, Wen-Biao; Zheng, Tian-Qing

2011-11-01

Heme oxygenase (HO, EC 1.14.99.3) catalyzes the oxidation of heme and performs vital roles in plant development and stress responses. Two HO isozymes exist in plants. Between these, HO-1 is an oxidative stress-response protein, and HO-2 usually exhibited constitutive expression. Although alfalfa HO-1 gene (MsHO1) has been investigated previously, HO2 is still poorly understood. In this study, we report the cloning and characterization of HO2 gene, MsHO2, from alfalfa (Medica sativa L.). The full-length cDNA of MsHO2 contains an ORF of 870 bp and encodes for 290 amino acid residues with a predicted molecular mass of 33.3 kDa. Similar to MsHO1, MsHO2 also appears to have an N-terminal transit peptide sequence for chloroplast import. Many conserved residues in plant HO were also conserved in MsHO2. However, unlike HO-1, the conserved histidine (His) required for heme-iron binding and HO activity was replaced by tyrosine (Tyr) in MsHO2. Further biochemical activity analysis of purified mature MsHO2 showed no HO activity, suggesting that MsHO2 may not be a true HO in nature. Semi-quantitative RT-PCR confirmed its maximum expression in the germinating seeds. Importantly, the expression levels of MsHO2 were up-regulated under sodium nitroprusside (SNP) and H(2)O(2) (especially) treatment, respectively.

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

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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.

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.

Are plant endogenous factors like ethylene modulators of the early oxidative stress induced by mercury?

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M Belén eMontero-Palmero

2014-08-01

Full Text Available The induction of oxidative stress is one of the quickest symptoms appearing in plants subjected to metal stress. A transcriptional analysis of the early responses of alfalfa (Medicago sativa seedlings to mercury (Hg; 3 µM for 3, 6 and 24 h showed that up-regulation of genes responding to ethylene were up-regulated, a phytohormone known to mediate in the cellular redox homeostasis. In this mini-review we have compared these quick responses with two other concurrent transcriptomic analysis in Barrel medic (Medicago truncatula and barley (Hordeum vulgare under Hg stress. Besides ethylene, ABA and jasmonate related genes were up-regulated, all of them are endogenous factors known to intervene in oxidative stress responses. The information obtained may target future work to understand the cellular mechanisms triggered by Hg, enabling biotechnological approaches to diminish Hg-induced phytotoxicity.

Loss of function of cinnamyl alcohol dehydrogenase 1 leads to unconventional lignin and a temperature-sensitive growth defect in Medicago truncatula.

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Zhao, Qiao; Tobimatsu, Yuki; Zhou, Rui; Pattathil, Sivakumar; Gallego-Giraldo, Lina; Fu, Chunxiang; Jackson, Lisa A; Hahn, Michael G; Kim, Hoon; Chen, Fang; Ralph, John; Dixon, Richard A

2013-08-13

There is considerable debate over the capacity of the cell wall polymer lignin to incorporate unnatural monomer units. We have identified Tnt1 retrotransposon insertion mutants of barrel medic (Medicago truncatula) that show reduced lignin autofluorescence under UV microscopy and red coloration in interfascicular fibers. The phenotype is caused by insertion of retrotransposons into a gene annotated as encoding cinnamyl alcohol dehydrogenase, here designated M. truncatula CAD1. NMR analysis indicated that the lignin is derived almost exclusively from coniferaldehyde and sinapaldehyde and is therefore strikingly different from classical lignins, which are derived mainly from coniferyl and sinapyl alcohols. Despite such a major alteration in lignin structure, the plants appear normal under standard conditions in the greenhouse or growth chamber. However, the plants are dwarfed when grown at 30 °C. Glycome profiling revealed an increased extractability of some xylan and pectin epitopes from the cell walls of the cad1-1 mutant but decreased extractability of others, suggesting that aldehyde-dominant lignin significantly alters cell wall structure.

Identification of genes that regulate phosphate acquisition and plant performance during arbuscular my corrhizal symbiosis in medicago truncatula and brachypodium distachyon

Energy Technology Data Exchange (ETDEWEB)

Harrison, Maria J [Boyce Thompson Institute, Ithaca, NY (United States); Hudson, Matthew E [Univ. of Illinois, Champaign, IL (United States)

2015-11-24

Most vascular flowering plants have the ability to form symbiotic associations with arbuscular mycorrhizal (AM) fungi. The symbiosis develops in the roots and can have a profound effect on plant productivity, largely through improvements in plant mineral nutrition. Within the root cortical cells, the plant and fungus create novel interfaces specialized for nutrient transfer, while the fungus also develops a network of hyphae in the rhizosphere. Through this hyphal network, the fungus acquires and delivers phosphate and nitrogen to the root. In return, the plant provides the fungus with carbon. In addition, to enhancing plant mineral nutrition, the AM symbiosis has an important role in the carbon cycle, and positive effects on soil health. Here we identified and characterized plant genes involved in the regulation and functioning of the AM symbiosis in Medicago truncatula and Brachypodium distachyon. This included the identification and and characterization of a M. truncatula transcription factors that are required for symbiosis. Additionally, we investigated the molecular basis of functional diversity among AM symbioses in B. distachyon and analysed the transcriptome of Brachypodium distachyon during symbiosis.

Drought stress provokes the down-regulation of methionine and ethylene biosynthesis pathways in Medicago truncatula roots and nodules.

Science.gov (United States)

Larrainzar, Estíbaliz; Molenaar, Johanna A; Wienkoop, Stefanie; Gil-Quintana, Erena; Alibert, Bénédicte; Limami, Anis M; Arrese-Igor, Cesar; González, Esther M

2014-09-01

Symbiotic nitrogen fixation is one of the first physiological processes inhibited in legume plants under water-deficit conditions. Despite the progress made in the last decades, the molecular mechanisms behind this regulation are not fully understood yet. Recent proteomic work carried out in the model legume Medicago truncatula provided the first indications of a possible involvement of nodule methionine (Met) biosynthesis and related pathways in response to water-deficit conditions. To better understand this involvement, the drought-induced changes in expression and content of enzymes involved in the biosynthesis of Met, S-adenosyl-L-methionine (SAM) and ethylene in M. truncatula root and nodules were analyzed using targeted approaches. Nitrogen-fixing plants were subjected to a progressive water deficit and a subsequent recovery period. Besides the physiological characterization of the plants, the content of total sulphur, sulphate and main S-containing metabolites was measured. Results presented here show that S availability is not a limiting factor in the drought-induced decline of nitrogen fixation rates in M. truncatula plants and provide evidences for a down-regulation of the Met and ethylene biosynthesis pathways in roots and nodules in response to water-deficit conditions. © 2014 John Wiley & Sons Ltd.

Multiple cis-regulatory elements are involved in the complex regulation of the sieve element-specific MtSEO-F1 promoter from Medicago truncatula.

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Bucsenez, M; Rüping, B; Behrens, S; Twyman, R M; Noll, G A; Prüfer, D

2012-09-01

The sieve element occlusion (SEO) gene family includes several members that are expressed specifically in immature sieve elements (SEs) in the developing phloem of dicotyledonous plants. To determine how this restricted expression profile is achieved, we analysed the SE-specific Medicago truncatula SEO-F1 promoter (PMtSEO-F1) by constructing deletion, substitution and hybrid constructs and testing them in transgenic tobacco plants using green fluorescent protein as a reporter. This revealed four promoter regions, each containing cis-regulatory elements that activate transcription in SEs. One of these segments also contained sufficient information to suppress PMtSEO-F1 transcription in the phloem companion cells (CCs). Subsequent in silico analysis revealed several candidate cis-regulatory elements that PMtSEO-F1 shares with other SEO promoters. These putative sieve element boxes (PSE boxes) are promising candidates for cis-regulatory elements controlling the SE-specific expression of PMtSEO-F1. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.

Experimental tolerance to boron of the plant species Nicotiana glauca, Jacaranda mimosifolia, Tecoma stans, Medicago sativa y Spinacea oleracea in Argentina

International Nuclear Information System (INIS)

Viana, Marta L. de; Albarracin Franco, Silvia

2008-01-01

The activity of the borate deposits industries constitutes a point source and diffuse pollution of air, soil and water. Therefore, the study and experimentation on possible ways to offset this impact is a priority. A relatively new technique to decontaminate soils is phytoremediation, which uses plants and associated microorganisms. The first step is to identify tolerant plant species, which is the focus of this work. An experiment was conducted in the laboratory to evaluate the germination, survival and growth of different species in different concentrations of boron. At the beginning and end of the experiment was determined concentration of boron in the substrate for each treatment and for substrates with and without vegetation. Significant differences due to treatment, the species and species-treatment interaction. M. sativa, N. glauca and J. mimosifolia were the species most tolerant to boron. The other species showed a decrease in all variables-response function of the concentration of the contaminant. All had low survival in the highest concentration. The decrease of boron was highest in the treatment of 30 ppm of boron with M. sativa and the lowest was recorded in the treatment of 20 ppm of boron with J. mimosifolia and 30 ppm of boron with T. stans and S. oleracea. It is concluded that N. glauca, M. sativa and J. mimosifolia could be considered as promising remediation. (author) [es

miR396 affects mycorrhization and root meristem activity in the legume Medicago truncatula.

Science.gov (United States)

Bazin, Jérémie; Khan, Ghazanfar Abbas; Combier, Jean-Philippe; Bustos-Sanmamed, Pilar; Debernardi, Juan Manuel; Rodriguez, Ramiro; Sorin, Céline; Palatnik, Javier; Hartmann, Caroline; Crespi, Martin; Lelandais-Brière, Christine

2013-06-01

The root system is crucial for acquisition of resources from the soil. In legumes, the efficiency of mineral and water uptake by the roots may be reinforced due to establishment of symbiotic relationships with mycorrhizal fungi and interactions with soil rhizobia. Here, we investigated the role of miR396 in regulating the architecture of the root system and in symbiotic interactions in the model legume Medicago truncatula. Analyses with promoter-GUS fusions suggested that the mtr-miR396a and miR396b genes are highly expressed in root tips, preferentially in the transition zone, and display distinct expression profiles during lateral root and nodule development. Transgenic roots of composite plants that over-express the miR396b precursor showed lower expression of six growth-regulating factor genes (MtGRF) and two bHLH79-like target genes, as well as reduced growth and mycorrhizal associations. miR396 inactivation by mimicry caused contrasting tendencies, with increased target expression, higher root biomass and more efficient colonization by arbuscular mycorrhizal fungi. In contrast to MtbHLH79, repression of three GRF targets by RNA interference severely impaired root growth. Early activation of mtr-miR396b, concomitant with post-transcriptional repression of MtGRF5 expression, was also observed in response to exogenous brassinosteroids. Growth limitation in miR396 over-expressing roots correlated with a reduction in cell-cycle gene expression and the number of dividing cells in the root apical meristem. These results link the miR396 network to the regulation of root growth and mycorrhizal associations in plants. © 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.

Flavonoids and Auxin Transport Inhibitors Rescue Symbiotic Nodulation in the Medicago truncatula Cytokinin Perception Mutant cre1

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Ng, Jason Liang Pin; Hassan, Samira; Truong, Thy T.; Hocart, Charles H.; Laffont, Carole; Frugier, Florian; Mathesius, Ulrike

2015-01-01

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. PMID:26253705

Producción, evaluación y caracterización microbiológica de un biofertilizante artesanal para la fijación de nitrógeno en especies vegetales forrajeras.

OpenAIRE

Reyes Villegas, María Isabel

2016-01-01

The increased production of grasslands in Ecuador has necessitated the use of chemical fertilizers, as in the case of commercial urea, which has caused impacts on agricultural land. As an alternative to this chemical fertilizer , developed , tested and characterized a craft biofertilizer made from roots of alfalfa ( Medicago sativa) , White Clover ( Trifolium repens ) and rye grass ( Lolium perenne), which has diazotrophic microbiological activity of bacterial species such...

Impact of cytomixis on meiosis, pollen viability and pollen size in ...

Indian Academy of Sciences (India)

Srinivas

mother cells of Medicago sativa L.; J. Heredity 94 512–516. Bhat T A, Parveen S and Khan A H 2006 MMS-induced cytomixis in pollen mother cells of broad bean (Vicia faba L.); Turk. J. Bot. 30 273–279. Bione N C P, Pagliarini M S and de Toledo J F F 2000 Meiotic behavior of several Brazilian soybean varieties; Genet.

Biological effect of aerospace environment on alfalfa

International Nuclear Information System (INIS)

Zhang Yuexue; Liu Jielin; Han Weibo; Tang Fenglan; Hao Ruochao; Shang Chen; DuYouying; Li Jikai; Wang Changshan

2009-01-01

The biological effect of aerospace environment on two varieties of Medicago sativa L. was studied. In M 1 germination results showed that aerospace environment increased cell division and the number of micronucleus, changed germination rate, caused seedling aberrations. Cytogenetical and seedling aberration of Zhaodong showed more sensitivity than Longmu 803. Branches and fresh weight of Zhaodong had shown more serious damage than control and Longmu 803. (authors)

High-quality draft genome sequence of Ensifer meliloti Mlalz-1, a microsymbiont of Medicago laciniata (L.) miller collected in Lanzarote, Canary Islands, Spain.

Science.gov (United States)

Osman, Wan Adnawani Meor; van Berkum, Peter; León-Barrios, Milagros; Velázquez, Encarna; Elia, Patrick; Tian, Rui; Ardley, Julie; Gollagher, Margaret; Seshadri, Rekha; Reddy, T B K; Ivanova, Natalia; Woyke, Tanja; Pati, Amrita; Markowitz, Victor; Baeshen, Mohamed N; Baeshen, Naseebh Nabeeh; Kyrpides, Nikos; Reeve, Wayne

2017-01-01

10.1601/nm.1335 Mlalz-1 (INSDC = ATZD00000000) is an aerobic, motile, Gram-negative, non-spore-forming rod that was isolated from an effective nitrogen-fixing nodule of Medicago laciniata (L.) Miller from a soil sample collected near the town of Guatiza on the island of Lanzarote, the Canary Islands, Spain. This strain nodulates and forms an effective symbiosis with the highly specific host M. laciniata . This rhizobial genome was sequenced as part of the DOE Joint Genome Institute 2010 Genomic Encyclopedia for Bacteria and Archaea-Root Nodule Bacteria (GEBA-RNB) sequencing project. Here the features of 10.1601/nm.1335 Mlalz-1 are described, together with high-quality permanent draft genome sequence information and annotation. The 6,664,116 bp high-quality draft genome is arranged in 99 scaffolds of 100 contigs, containing 6314 protein-coding genes and 74 RNA-only encoding genes. Strain Mlalz-1 is closely related to 10.1601/nm.1335 10.1601/strainfinder?urlappend=%3Fid%3DIAM+12611 T , 10.1601/nm.1334 A 321 T and 10.1601/nm.17831 10.1601/strainfinder?urlappend=%3Fid%3DORS+1407 T , based on 16S rRNA gene sequences. gANI values of ≥98.1% support the classification of strain Mlalz-1 as 10.1601/nm.1335. Nodulation of M. laciniata requires a specific nodC allele, and the nodC gene of strain Mlalz-1 shares ≥98% sequence identity with nodC of M. laciniata -nodulating 10.1601/nm.1328 strains, but ≤93% with nodC of 10.1601/nm.1328 strains that nodulate other Medicago species. Strain Mlalz-1 is unique among sequenced 10.1601/nm.1335 strains in possessing genes encoding components of a T2SS and in having two versions of the adaptive acid tolerance response lpiA-acvB operon. In 10.1601/nm.1334 strain 10.1601/strainfinder?urlappend=%3Fid%3DWSM+419, lpiA is essential for enhancing survival in lethal acid conditions. The second copy of the lpiA-acvB operon of strain Mlalz-1 has highest sequence identity (> 96%) with that of 10.1601/nm.1334 strains, which suggests genetic

Effects of the mycorrhizal fungus ¤Glomus intraradices¤ on uranium uptake and accumulation by ¤Medicago truncatula¤ L. from uranium-contaminated soil

DEFF Research Database (Denmark)

Chen, B.D.; Jakobsen, I.; Roos, P.

2005-01-01

cultivation system facilitating the specific measurement of U uptake by roots, AM roots and extraradical hyphae of AM fungi and the measurement of U partitioning between root and shoot. A soil-filled plastic pot constituted the main root compartment (C-A) which contained a plastic vial filled with U......-contaminated soil amended with 0, 50 or 200 mg KH2PO4-P kg(-1) soil (C-B). The vial was sealed by coarse or fine nylon mesh, permitting the penetration of both roots and hyphae or of just hyphae. Medicago truncatula plants grown in C-A were inoculated with G. intraradices or remained uninoculated. Dry weight...... in C-A, but decreased shoot U concentrations. Root U concentrations and contents were significantly higher when only hyphae could access U inside C-B than when roots could also directly access this U pool. The proportion of plant U content partitioned to shoots was decreased by root exclusion from C...

Multiple mutualist effects on genomewide expression in the tripartite association between Medicago truncatula, nitrogen-fixing bacteria and mycorrhizal fungi.

Science.gov (United States)

Afkhami, Michelle E; Stinchcombe, John R

2016-10-01

While all species interact with multiple mutualists, the fitness consequences and molecular mechanisms underlying these interactions remain largely unknown. We combined factorial ecological experiments with genomewide expression analyses to examine the phenotypic and transcriptomic responses of model legume Medicago truncatula to rhizobia and mycorrhizal fungi. We found synergistic effects of these mutualists on plant performance and examined unique features of plant gene expression responses to multiple mutualists. There were genomewide signatures of mutualists and multiple mutualists on expression, with partners often affecting unique sets of genes. Mycorrhizal fungi had stronger effects on plant expression than rhizobia, with 70% of differentially expressed genes affected by fungi. Fungal and bacterial mutualists had joint effects on 10% of differentially expressed genes, including unexpected, nonadditive effects on some genes with important functions such as nutrient metabolism. For a subset of genes, interacting with multiple mutualists even led to reversals in the direction of expression (shifts from up to downregulation) compared to interacting with single mutualists. Rhizobia also affected the expression of several mycorrhizal genes, including those involved in nutrient transfer to host plants, indicating that partner species can also impact each other's molecular phenotypes. Collectively, these data illustrate the diverse molecular mechanisms and transcriptional responses associated with the synergistic benefits of multiple mutualists. © 2016 John Wiley & Sons Ltd.

The plasma membrane proteome of Medicago truncatula roots as modified by arbuscular mycorrhizal symbiosis.

Science.gov (United States)

Aloui, Achref; Recorbet, Ghislaine; Lemaître-Guillier, Christelle; Mounier, Arnaud; Balliau, Thierry; Zivy, Michel; Wipf, Daniel; Dumas-Gaudot, Eliane

2018-01-01

In arbuscular mycorrhizal (AM) roots, the plasma membrane (PM) of the host plant is involved in all developmental stages of the symbiotic interaction, from initial recognition to intracellular accommodation of intra-radical hyphae and arbuscules. Although the role of the PM as the agent for cellular morphogenesis and nutrient exchange is especially accentuated in endosymbiosis, very little is known regarding the PM protein composition of mycorrhizal roots. To obtain a global overview at the proteome level of the host PM proteins as modified by symbiosis, we performed a comparative protein profiling of PM fractions from Medicago truncatula roots either inoculated or not with the AM fungus Rhizophagus irregularis. PM proteins were isolated from root microsomes using an optimized discontinuous sucrose gradient; their subsequent analysis by liquid chromatography followed by mass spectrometry (MS) identified 674 proteins. Cross-species sequence homology searches combined with MS-based quantification clearly confirmed enrichment in PM-associated proteins and depletion of major microsomal contaminants. Changes in protein amounts between the PM proteomes of mycorrhizal and non-mycorrhizal roots were monitored further by spectral counting. This workflow identified a set of 82 mycorrhiza-responsive proteins that provided insights into the plant PM response to mycorrhizal symbiosis. Among them, the association of one third of the mycorrhiza-responsive proteins with detergent-resistant membranes pointed at partitioning to PM microdomains. The PM-associated proteins responsive to mycorrhization also supported host plant control of sugar uptake to limit fungal colonization, and lipid turnover events in the PM fraction of symbiotic roots. Because of the depletion upon symbiosis of proteins mediating the replacement of phospholipids by phosphorus-free lipids in the plasmalemma, we propose a role of phosphate nutrition in the PM composition of mycorrhizal roots.

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

Directory of Open Access Journals (Sweden)

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.

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.

Green Fodder Production and Water Use Efficiency of Some Forage Crops under Hydroponic Conditions

OpenAIRE

Ghazi N. Al-Karaki; M. Al-Hashimi

2012-01-01

The objectives of this study were to evaluate five forage crops (alfalfa (Medicago sativa), barley (Hordeum vulgare), cowpea (Vigna unguiculata), sorghum (Sorghum bicolor), and wheat (Triticum aestivum)) for green fodder production and water use efficiency under hydroponic conditions. The experiment has been conducted under temperature-controlled conditions (24 ± 1°C) and natural window illumination at growth room of Soilless Culture Laboratory, Arabian Gulf University, Manama, Bahrain. The r...

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. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Polyamines contribute to salinity tolerance in the symbiosis Medicago truncatula-Sinorhizobium meliloti by preventing oxidative damage.

Science.gov (United States)

López-Gómez, Miguel; Hidalgo-Castellanos, Javier; Muñoz-Sánchez, J Rubén; Marín-Peña, Agustín J; Lluch, Carmen; Herrera-Cervera, José A

2017-07-01

Polyamines (PAs) such as spermidine (Spd) and spermine (Spm) are small ubiquitous polycationic compounds that contribute to plant adaptation to salt stress. The positive effect of PAs has been associated to a cross-talk with other anti-stress hormones such as brassinosteroids (BRs). In this work we have studied the effects of exogenous Spd and Spm pre-treatments in the response to salt stress of the symbiotic interaction between Medicago truncatula and Sinorhizobium meliloti by analyzing parameters related to nitrogen fixation, oxidative damage and cross-talk with BRs in the response to salinity. Exogenous PAs treatments incremented the foliar and nodular Spd and Spm content which correlated with an increment of the nodule biomass and nitrogenase activity. Exogenous Spm treatment partially prevented proline accumulation which suggests that this polyamine could replace the role of this amino acid in the salt stress response. Additionally, Spd and Spm pre-treatments reduced the levels of H 2 O 2 and lipid peroxidation under salt stress. PAs induced the expression of genes involved in BRs biosynthesis which support a cross-talk between PAs and BRs in the salt stress response of M. truncatula-S. meliloti symbiosis. In conclusion, exogenous PAs improved the response to salinity of the M. truncatula-S. meliloti symbiosis by reducing the oxidative damage induced under salt stress conditions. In addition, in this work we provide evidences of the cross-talk between PAs and BRs in the adaptive responses to salinity. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Toxicological responses in alfalfa ( Medicago sativa ) under joint ...

African Journals Online (AJOL)

Joint effects of Cd2+ and napropamide in seeds, roots or leaves of alfalfa were investigated under different treatments. It was shown that single stress of Cd2+ or napropamide decreased chlorophyll content after 30 days of treatment in different concentrations. The decrease in chlorophyll content became insignificant under ...

Biochemical responses of Alfalfa (Medicago sativa L.) cultivars ...

African Journals Online (AJOL)

Administrator

2011-09-21

Sep 21, 2011 ... cultivars, as shown by the increase in lipid peroxidation. However, the level of lipid ..... Moreover, salinity perturbs plant hormone balances. (Khan and Rizvi, 1994) and ..... water deficit and desiccation. New Phytol. 125: 27-58.

Toxicological responses in alfalfa (Medicago sativa) under joint ...

African Journals Online (AJOL)

AJL-021

2012-11-13

Nov 13, 2012 ... 1School of Chemical Engineering, Huaihai Institute of Technology, Lianyungang City, ... would aggravate the toxic effects on chlorophyll synthesis in ... O2. •− was also higher in the napropamide treatments than in the control.

Rhizobia from Lanzarote, the Canary Islands, That Nodulate Phaseolus vulgaris Have Characteristics in Common with Sinorhizobium meliloti Isolates from Mainland Spain▿

Science.gov (United States)

Zurdo-Piñeiro, José Luis; García-Fraile, Paula; Rivas, Raúl; Peix, Alvaro; León-Barrios, Milagros; Willems, Anne; Mateos, Pedro Francisco; Martínez-Molina, Eustoquio; Velázquez, Encarna; van Berkum, Peter

2009-01-01

The stable, low-molecular-weight (LMW) RNA fractions of several rhizobial isolates of Phaseolus vulgaris grown in the soil of Lanzarote, an island of the Canary Islands, were identical to a less-common pattern found within Sinorhizobium meliloti (assigned to group II) obtained from nodules of alfalfa and alfalfa-related legumes grown in northern Spain. The P. vulgaris isolates and the group II LMW RNA S. meliloti isolates also were distinguishable in that both had two conserved inserts of 20 and 46 bp in the 16S-23S internal transcribed spacer region that were not present in other strains of S. meliloti. The isolates from P. vulgaris nodulated bean but not Medicago sativa, while those recovered from Medicago, Melilotus, and Trigonella spp. nodulated both host legumes. The bean isolates also were distinguished from those of Medicago, Melilotus, and Trigonella spp. by nodC sequence analysis. The nodC sequences of the bean isolates were most similar to those reported for S. meliloti bv. mediterranense and Sinorhizobium fredii bv. mediterranense (GenBank accession numbers DQ333891 and AF217267, respectively). None of the evidence placed the bean isolates from Lanzarote in the genus Rhizobium, which perhaps is inconsistent with seed-borne transmission of Rhizobium etli from the Americas to the Canaries as an explanation for the presence of bean-nodulating rhizobia in soils of Lanzarote. PMID:19218416

Rhizobia from Lanzarote, the Canary Islands, that nodulate Phaseolus vulgaris have characteristics in common with Sinorhizobium meliloti isolates from mainland Spain.

Science.gov (United States)

Zurdo-Piñeiro, José Luis; García-Fraile, Paula; Rivas, Raúl; Peix, Alvaro; León-Barrios, Milagros; Willems, Anne; Mateos, Pedro Francisco; Martínez-Molina, Eustoquio; Velázquez, Encarna; van Berkum, Peter

2009-04-01

The stable, low-molecular-weight (LMW) RNA fractions of several rhizobial isolates of Phaseolus vulgaris grown in the soil of Lanzarote, an island of the Canary Islands, were identical to a less-common pattern found within Sinorhizobium meliloti (assigned to group II) obtained from nodules of alfalfa and alfalfa-related legumes grown in northern Spain. The P. vulgaris isolates and the group II LMW RNA S. meliloti isolates also were distinguishable in that both had two conserved inserts of 20 and 46 bp in the 16S-23S internal transcribed spacer region that were not present in other strains of S. meliloti. The isolates from P. vulgaris nodulated bean but not Medicago sativa, while those recovered from Medicago, Melilotus, and Trigonella spp. nodulated both host legumes. The bean isolates also were distinguished from those of Medicago, Melilotus, and Trigonella spp. by nodC sequence analysis. The nodC sequences of the bean isolates were most similar to those reported for S. meliloti bv. mediterranense and Sinorhizobium fredii bv. mediterranense (GenBank accession numbers DQ333891 and AF217267, respectively). None of the evidence placed the bean isolates from Lanzarote in the genus Rhizobium, which perhaps is inconsistent with seed-borne transmission of Rhizobium etli from the Americas to the Canaries as an explanation for the presence of bean-nodulating rhizobia in soils of Lanzarote.

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

Phytoextraction of Heavy Metals from Soil Polluted with Waste Mining by Using Forage Plants in Successive Cultures

Directory of Open Access Journals (Sweden)

Anca Pricop

2010-10-01

Full Text Available During two years, was studied the phytoextraction potential of some perennial species (Medicago sativa and Trifolium pretense, Festuca arundinacea and Lolium perenne, for Zn, Cd, and Pb from soils polluted with waste mining. The experiment was done on kernozem soil with adding of 20 kg waste mining/m2 and 8 kg biosolid/m2. The results showed that in all experiments, rye-grass is a good extractor for Zn and Cd, and leguminous species for Pb. Both leguminous species, especially M. sativa, presented a high tolerance for lead toxicity, even with 3-4 times greater values than maximum allowable level from actual legislation. In all cases, regardless of the experimental variant, raygrass (Lolium perenne is a good accumulator of Zn and Cd, and red clover (Trifolium pratense of Pb. The values of metal bioaccumulation increase gradually with their concentration in soil. Quality of very good extractor of Pb displayed by Trifolium pratense species are kept even in case of excessive pollution with Pb, when it exceed 3.4 times the maximum permissible norms. This proves, as Medicago sativa species, a good tolerance and resistance to toxicity of this metal. In case of addition of natural zeolite-volcanic tuff there was no increase in the rate of Zn bioaccumulation. Only in case of Cd at Lolium perenne and Pb at Trifolium pratense appear the favourable effect of metallic ions bioavailability in soil for plants.

The Transcriptional Repressor MYB2 Regulates Both Spatial and Temporal Patterns of Proanthocyandin and Anthocyanin Pigmentation in Medicago truncatula[OPEN

Science.gov (United States)

2015-01-01

Accumulation of anthocyanins and proanthocyanidins (PAs) is limited to specific cell types and developmental stages, but little is known about how antagonistically acting transcriptional regulators work together to determine temporal and spatial patterning of pigmentation at the cellular level, especially for PAs. Here, we characterize MYB2, a transcriptional repressor regulating both anthocyanin and PA biosynthesis in the model legume Medicago truncatula. MYB2 was strongly upregulated by MYB5, a major regulator of PA biosynthesis in M. truncatula and a component of MYB-basic helix loop helix-WD40 (MBW) activator complexes. Overexpression of MYB2 abolished anthocyanin and PA accumulation in M. truncatula hairy roots and Arabidopsis thaliana seeds, respectively. Anthocyanin deposition was expanded in myb2 mutant seedlings and flowers accompanied by increased anthocyanin content. PA mainly accumulated in the epidermal layer derived from the outer integument in the M. truncatula seed coat, starting from the hilum area. The area of PA accumulation and ANTHOCYANIDIN REDUCTASE expression was expanded into the seed body at the early stage of seed development in the myb2 mutant. Genetic, biochemical, and cell biological evidence suggests that MYB2 functions as part of a multidimensional regulatory network to define the temporal and spatial pattern of anthocyanin and PA accumulation linked to developmental processes. PMID:26410301

Roughage digestion evaluation in horses with total feces collection and mobile nylon bags

OpenAIRE

Rodrigues, Liziana Maria; Almeida, Fernando Queiroz de; Pereira, Marcos Barreto; Miranda, Ana Cláudia Tavares; Guimarães, Andresa; Andrade, Agnaldo Machado de

2012-01-01

This study aimed to evaluate the nutrient digestibility of roughages in horses with total feces collection and mobile bags. Two trials were carried out simultaneously. The first trial evaluated the digestibility of nutrients of coastcross hay (Cynodon dactylon cv. coastcross) with total feces collection. The second trial assessed the digestibility of nutrients of alfalfa hay (Medicago sativa), peanut (Arachis pintoi) and coastcross hay with mobile bags. This trial was conducted with gastric i...

Correlations of Glomalin Contents and PAHs Removal in Alfalfa-vegetated Soils with Inoculation of Arbuscular Mycorrhizal Fungi

OpenAIRE

YANG Zhen-ya; ZONG Jiong; ZHU Xue-zhu; LING Wan-ting

2016-01-01

The correlations of glomalin contents and removal of phenanthrene and pyrene as representative polycyclic aromatic hydrocarbons (PAHs) in soils with inoculation of arbuscular mycorrhizal fungi(AMF) were investigated. The test AMF included Glomus etunicatum(Ge), Glomus mosseae(Gm), and Glomus lamellosum(Gla), and the host plant was alfalfa(Medicago sativa L.). The AMF hyphal density and contents of easily extractable glomalin and total glomalin in AMF-inoculated soils were observed to increase...

The Transcriptional Repressor MYB2 Regulates Both Spatial and Temporal Patterns of Proanthocyandin and Anthocyanin Pigmentation in Medicago truncatula.

Science.gov (United States)

Jun, Ji Hyung; Liu, Chenggang; Xiao, Xirong; Dixon, Richard A

2015-10-01

Accumulation of anthocyanins and proanthocyanidins (PAs) is limited to specific cell types and developmental stages, but little is known about how antagonistically acting transcriptional regulators work together to determine temporal and spatial patterning of pigmentation at the cellular level, especially for PAs. Here, we characterize MYB2, a transcriptional repressor regulating both anthocyanin and PA biosynthesis in the model legume Medicago truncatula. MYB2 was strongly upregulated by MYB5, a major regulator of PA biosynthesis in M. truncatula and a component of MYB-basic helix loop helix-WD40 (MBW) activator complexes. Overexpression of MYB2 abolished anthocyanin and PA accumulation in M. truncatula hairy roots and Arabidopsis thaliana seeds, respectively. Anthocyanin deposition was expanded in myb2 mutant seedlings and flowers accompanied by increased anthocyanin content. PA mainly accumulated in the epidermal layer derived from the outer integument in the M. truncatula seed coat, starting from the hilum area. The area of PA accumulation and ANTHOCYANIDIN REDUCTASE expression was expanded into the seed body at the early stage of seed development in the myb2 mutant. Genetic, biochemical, and cell biological evidence suggests that MYB2 functions as part of a multidimensional regulatory network to define the temporal and spatial pattern of anthocyanin and PA accumulation linked to developmental processes. © 2015 American Society of Plant Biologists. All rights reserved.

Novel MtCEP1 peptides produced in vivo differentially regulate root development in Medicago truncatula.

Science.gov (United States)

Mohd-Radzman, Nadiatul A; Binos, Steve; Truong, Thy T; Imin, Nijat; Mariani, Michael; Djordjevic, Michael A

2015-08-01

Small, post-translationally modified and secreted peptides regulate diverse plant developmental processes. Due to low natural abundance, it is difficult to isolate and identify these peptides. Using an improved peptide isolation protocol and Orbitrap mass spectrometry, nine 15-amino-acid CEP peptides were identified that corresponded to the two domains encoded by Medicago truncatula CEP1 (MtCEP1). Novel arabinosylated and hydroxylated peptides were identified in root cultures overexpressing MtCEP1. The five most abundant CEP peptides were hydroxylated and these species were detected also in low amounts in vector control samples. Synthetic peptides with different hydroxylation patterns differentially affected root development. Notably, the domain 1 peptide hydroxylated at Pro4 and Pro11 (D1:HyP4,11) imparted the strongest inhibition of lateral root emergence when grown with 5mM KNO3 and stimulated the highest increase in nodule number when grown with 0mM KNO3. Inhibition of lateral root emergence by D1:HyP4,11 was not alleviated by removing peptide exposure. In contrast, the domain 2 peptide hydroxylated at Pro11 (D2:HyP11) increased stage III-IV lateral root primordium numbers by 6-fold (P emerge. Auxin addition at levels which stimulated lateral root formation in wild-type plants had little or no ameliorating effect on CEP peptide-mediated inhibition of lateral root formation or emergence. Both peptides increased and altered the root staining pattern of the auxin-responsive reporter GH3:GUS suggesting CEPs alter auxin sensitivity or distribution. The results showed that CEP primary sequence and post-translational modifications influence peptide activities and the improved isolation procedure effectively and reproducibly identifies and characterises CEPs. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

W342F Mutation in CCaMK Enhances Its Affinity to Calmodulin But Compromises Its Role in Supporting Root Nodule Symbiosis in Medicago truncatula

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Edgard Jauregui

2017-11-01

Full Text Available The calcium/calmodulin-dependent protein kinase (CCaMK is regulated by free Ca2+ and Ca2+-loaded calmodulin. This dual binding is believed to be involved in its regulation and associated physiological functions, although direct experimental evidence for this is lacking. Here we document that site-directed mutations in the calmodulin-binding domain of CCaMK alters its binding capacity to calmodulin, providing an effective approach to study how calmodulin regulates CCaMK in terms of kinase activity and regulation of rhizobial symbiosis in Medicago truncatula. We observed that mutating the tryptophan at position 342 to phenylalanine (W342F markedly increased the calmodulin-binding capability of the mutant. The mutant CCaMK underwent autophosphorylation and catalyzed substrate phosphorylation in the absence of calcium and calmodulin. When the mutant W342F was expressed in ccamk-1 roots, the transgenic roots exhibited an altered nodulation phenotype. These results indicate that altering the calmodulin-binding domain of CCaMK could generate a constitutively activated kinase with a negative role in the physiological function of CCaMK.

A Medicago truncatula rdr6 allele impairs transgene silencing and endogenous phased siRNA production but not development.

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Bustos-Sanmamed, Pilar; Hudik, Elodie; Laffont, Carole; Reynes, Christelle; Sallet, Erika; Wen, Jiangqi; Mysore, Kirankumar S; Camproux, Anne-Claude; Hartmann, Caroline; Gouzy, Jérome; Frugier, Florian; Crespi, Martin; Lelandais-Brière, Christine

2014-12-01

RNA-dependent RNA polymerase 6 (RDR6) and suppressor of gene silencing 3 (SGS3) act together in post-transcriptional transgene silencing mediated by small interfering RNAs (siRNAs) and in biogenesis of various endogenous siRNAs including the tasiARFs, known regulators of auxin responses and plant development. Legumes, the third major crop family worldwide, has been widely improved through transgenic approaches. Here, we isolated rdr6 and sgs3 mutants in the model legume Medicago truncatula. Two sgs3 and one rdr6 alleles led to strong developmental defects and impaired biogenesis of tasiARFs. In contrast, the rdr6.1 homozygous plants produced sufficient amounts of tasiARFs to ensure proper development. High throughput sequencing of small RNAs from this specific mutant identified 354 potential MtRDR6 substrates, for which siRNA production was significantly reduced in the mutant. Among them, we found a large variety of novel phased loci corresponding to protein-encoding genes or transposable elements. Interestingly, measurement of GFP expression revealed that post-transcriptional transgene silencing was reduced in rdr6.1 roots. Hence, this novel mis-sense mutation, affecting a highly conserved amino acid residue in plant RDR6s, may be an interesting tool both to analyse endogenous pha-siRNA functions and to improve transgene expression, at least in legume species. © 2014 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

Arbuscular mycorrhizal symbiosis can mitigate the negative effects of night warming on physiological traits of Medicago truncatula L.

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Hu, Yajun; Wu, Songlin; Sun, Yuqing; Li, Tao; Zhang, Xin; Chen, Caiyan; Lin, Ge; Chen, Baodong

2015-02-01

Elevated night temperature, one of the main climate warming scenarios, can have profound effects on plant growth and metabolism. However, little attention has been paid to the potential role of mycorrhizal associations in plant responses to night warming, although it is well known that symbiotic fungi can protect host plants against various environmental stresses. In the present study, physiological traits of Medicago truncatula L. in association with the arbuscular mycorrhizal (AM) fungus Rhizophagus irregularis were investigated under simulated night warming. A constant increase in night temperature of 1.53 °C significantly reduced plant shoot and root biomass, flower and seed number, leaf sugar concentration, and shoot Zn and root P concentrations. However, the AM association essentially mitigated these negative effects of night warming by improving plant growth, especially through increased root biomass, root to shoot ratio, and shoot Zn and root P concentrations. A significant interaction was observed between R. irregularis inoculation and night warming in influencing both root sucrose concentration and expression of sucrose synthase (SusS) genes, suggesting that AM symbiosis and increased night temperature jointly regulated plant sugar metabolism. Night warming stimulated AM fungal colonization but did not influence arbuscule abundance, symbiosis-related plant or fungal gene expression, or growth of extraradical mycelium, indicating little effect of night warming on the development or functioning of AM symbiosis. These findings highlight the importance of mycorrhizal symbiosis in assisting plant resilience to climate warming.

Survival and growth of Alfalfa (Medicago sativa l.) inoculated with an am fungus (Glomus intraradices) in contaminated soils treated with two different remediation technologies (bio-pile and thermal desorption)

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Norini, M.P.; Beguiristain, Th.; Leyval, C.

2005-01-01

Polycyclic aromatic hydrocarbons (PAHs) represent a group of persistent and toxic soil pollutants that are of major public concern due to their mutagenic and carcinogenic property. Phyto-remediation is the use of plants and their associated microorganisms for remediation of polluted soils. Phyto-remediation could be used in conjunction with other remediation technologies to reduce the contamination to safe levels and maintain or restore soil physico-chemical and biological properties. Most plant species form mycorrhizas with symbiotic fungi. It was shown that AM fungi enhance survival and plant growth in PAH contaminated soils. Mycorrhizal fungi also enhance the biotransformation or biodegradation of PAH, although the effect differed between soils. A rhizosphere and myco-rhizosphere gradient of PAH concentrations was observed, with decreased PAH concentration with decreased distance to roots. Different microbial communities were found in the rhizosphere of AM and non-mycorrhizal plants in comparison to bulk soil, suggesting that AM could affect PAH degradation by changing microbial communities. We investigated the effect of mycorrhizal fungi and nutrients on the ability of alfalfa to grow on soil contaminated with PAHs before and after two remediation treatments. We used soil from an industrial site (Homecourt, North East part of France) highly contaminated with PAH (2000 mg kg -1 ), which has been partially treated by two different remediation technologies (bio-pile and thermal desorption). The bio-pile treatment consisted of piling the contaminated soil with stimulation of aerobic microbial activity by aeration and addition of nutrient solution, and reduced PAH concentration to around 300 mg kg-1. With the thermal desorption treatment the soil was heated to around 500 deg. C so that PAH vaporized and were separated from the soil. The residual PAH concentration in soil was 40 mg kg -1 . Treated and non-treated contaminated soil was planted with alfalfa (Medicago

Rhizobial symbiosis effect on the growth, metal uptake, and antioxidant responses of Medicago lupulina under copper stress.

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Kong, Zhaoyu; Mohamad, Osama Abdalla; Deng, Zhenshan; Liu, Xiaodong; Glick, Bernard R; Wei, Gehong

2015-08-01

The effects of rhizobial symbiosis on the growth, metal uptake, and antioxidant responses of Medicago lupulina in the presence of 200 mg kg(-1) Cu(2+) throughout different stages of symbiosis development were studied. The symbiosis with Sinorhizobium meliloti CCNWSX0020 induced an increase in plant growth and nitrogen content irrespective of the presence of Cu(2+). The total amount of Cu uptake of inoculated plants significantly increased by 34.0 and 120.4% in shoots and roots, respectively, compared with non-inoculated plants. However, although the rhizobial symbiosis promoted Cu accumulation both in shoots and roots, the increase in roots was much higher than in shoots, thus decreasing the translocation factor and helping Cu phytostabilization. The rate of lipid peroxidation was significantly decreased in both shoots and roots of inoculated vs. non-inoculated plants when measured either 8, 13, or 18 days post-inoculation. In comparison with non-inoculated plants, the activities of superoxide dismutase and ascorbate peroxidase of shoots of inoculated plants exposed to excess Cu were significantly elevated at different stages of symbiosis development; similar increases occurred in the activities of superoxide dismutase, catalase, and glutathione reductase of inoculated roots. The symbiosis with S. meliloti CCNWSX0020 also upregulated the corresponding genes involved in antioxidant responses in the plants treated with excess Cu. The results indicated that the rhizobial symbiosis with S. meliloti CCNWSX0020 not only enhanced plant growth and metal uptake but also improved the responses of plant antioxidant defense to excess Cu stress.

Nutrient demand and fungal access to resources control the carbon allocation to the symbiotic partners in tripartite interactions of Medicago truncatula.

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Kafle, Arjun; Garcia, Kevin; Wang, Xiurong; Pfeffer, Philip E; Strahan, Gary D; Bücking, Heike

2018-06-02

Legumes form tripartite interactions with arbuscular mycorrhizal (AM) fungi and rhizobia, and both root symbionts exchange nutrients against carbon from their host. The carbon costs of these interactions are substantial, but our current understanding of how the host controls its carbon allocation to individual root symbionts is limited. We examined nutrient uptake and carbon allocation in tripartite interactions of Medicago truncatula under different nutrient supply conditions, and when the fungal partner had access to nitrogen, and followed the gene expression of several plant transporters of the SUT and SWEET family. Tripartite interactions led to synergistic growth responses and stimulated the phosphate and nitrogen uptake of the plant. Plant nutrient demand but also fungal access to nutrients played an important role for the carbon transport to different root symbionts, and the plant allocated more carbon to rhizobia under nitrogen demand, but more carbon to the fungal partner when nitrogen was available. These changes in carbon allocation were consistent with changes in the SUT and SWEET expression. Our study provides important insights into how the host plant controls its carbon allocation under different nutrient supply conditions and changes its carbon allocation to different root symbionts to maximize its symbiotic benefits. This article is protected by copyright. All rights reserved.

MtCAS31 Aids Symbiotic Nitrogen Fixation by Protecting the Leghemoglobin MtLb120-1 Under Drought Stress in Medicago truncatula

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Xin Li

2018-05-01

Full Text Available Symbiotic nitrogen fixation (SNF in legume root nodules injects millions of tons of nitrogen into agricultural lands and provides ammonia to non-legume crops under N-deficient conditions. During plant growth and development, environmental stresses, such as drought, salt, cold, and heat stress are unavoidable. This raises an interesting question as to how the legumes cope with the environmental stress along with SNF. Under drought stress, dehydrin proteins are accumulated, which function as protein protector and osmotic substances. In this study, we found that the dehydrin MtCAS31 (cold-acclimation-specific 31 functions in SNF in Medicago truncatula during drought stress. We found that MtCAS31 is expressed in nodules and interacts with leghemoglobin MtLb120-1. The interaction between the two proteins protects MtLb120-1 from denaturation under thermal stress in vivo. Compared to wild type, cas31 mutants display a lower nitrogenase activity, a lower ATP/ADP ratio, higher expression of nodule senescence genes and higher accumulation of amyloplasts under dehydration conditions. The results suggested that MtCAS31 protects MtLb120-1 from the damage of drought stress. We identified a new function for dehydrins in SNF under drought stress, which enriches the understanding of the molecular mechanism of dehydrins.

Genome-Wide Identification, Evolutionary Analysis and Expression Profiles of LATERAL ORGAN BOUNDARIES DOMAIN Gene Family in Lotus japonicus and Medicago truncatula.

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Tianquan Yang

Full Text Available The LATERAL ORGAN BOUNDARIES DOMAIN (LBD gene family has been well-studied in Arabidopsis and play crucial roles in the diverse growth and development processes including establishment and maintenance of boundary of developmental lateral organs. In this study we identified and characterized 38 LBD genes in Lotus japonicus (LjLBD and 57 LBD genes in Medicago truncatula (MtLBD, both of which are model legume plants that have some specific development features absent in Arabidopsis. The phylogenetic relationships, their locations in the genome, genes structure and conserved motifs were examined. The results revealed that all LjLBD and MtLBD genes could be distinctly divided into two classes: Class I and II. The evolutionary analysis showed that Type I functional divergence with some significantly site-specific shifts may be the main force for the divergence between Class I and Class II. In addition, the expression patterns of LjLBD genes uncovered the diverse functions in plant development. Interestingly, we found that two LjLBD proteins that were highly expressed during compound leaf and pulvinus development, can interact via yeast two-hybrid assays. Taken together, our findings provide an evolutionary and genetic foundation in further understanding the molecular basis of LBD gene family in general, specifically in L. japonicus and M. truncatula.

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

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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

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

Science.gov (United States)

Castillejo, Ma Angeles; Maldonado, Ana M; Dumas-Gaudot, Eliane; Fernández-Aparicio, Mónica; Susín, Rafael; Diego, Rubiales; Jorrín, Jesús V

2009-07-03

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. 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. 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 compared with those previously obtained with pea 1 and

PENINGKATAN PRODUKSI DAN KECERNAAN BAHAN KERING ALFALFA DENGAN PEMUPUKAN FOSFAT

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- Sunarni

2014-06-01

Full Text Available Alfalfa (Medicago    sativa    L. as one of legume forage crops for ruminant livestock is very sensitive to the phosphorus deficiency. Phosphorus fertilizers have been used widely to overcome those problem. However, the high cost of superphosphate (SP is now focusing attention on cheaper rock phosphate (RP fertilizer. A field experiment was conducted on a latosolic soil (low pH, and low available Bray II extractable P. The objective of the research is to evaluate the effect of phosphorus fertilizer from difference sources on dry matter production, and in    vitro dry matter digestibility of alfalfa. Completely randomized block design with 7 treatments in 3 replicates was used in this field experiment. The treatments were T0 (control, T1 (SP, 100 kg P2O5/ha, T2 (SP, 200 kg P2O5/ha, T3 (SP, 300 kg P2O5/ha, T4 (RP, 100 kg P2O5/ha, T5 (RP, 200 kg P2O5/ha, T6 (RP, 300 kg P2O5/ha. Size of each plot was 2 m x 2 m, and fertilized with P fertilizer (SP, RP according to the assigned treatment. All plot received basal fertilizer of urea (50 kg N/ha, KCl (100 kg K2O/ha and poultry manure (2 ton/ha. Medicago    sativa was defoliated on 12 weeks after planting and analyzed for dry matter (DM production and in    vitro DM digestibility. Result showed that DM production significantly influenced by the treatments. Superphosphate fertilization resulted DM production significantly higher compared to control and RP, except on RP 300 kg P2O5/ha was non-significant difference. In    vitro dry matter digestibility (IVDMD of alfalfa was not affected by the treatment. There was non-significant difference in IVDMD between the treatments. Therefore, RP (300 kg P2O5/ha could replace SP to increased DM production and not affected for IVDMD of Medicago    sativa in acid latosolic soil.

The Role of Proanthocyanidins Complex in Structure and Nutrition Interaction in Alfalfa Forage

OpenAIRE

Jonker, Arjan; Yu, Peiqiang

2016-01-01

Alfalfa (Medicago sativa L.) is one of the main forages grown in the world. Alfalfa is a winter hardy, drought tolerant, N-fixing legume with a good longevity, high yield, high nutrient levels, high digestibility, unique structural to non-structural components ratio, high dry matter intake, and high animal productivity per hectare. However, its main limitation is its excessively rapid initial rate of protein degradation in the rumen, which results in pasture bloat and inefficient use of prote...

Nitrogen replacement value of alfalfa to corn and wheat under irrigated Mediterranean conditions

OpenAIRE

Ballesta, A.; Lloveras, J.

2010-01-01

In crop rotations that include alfalfa (Medicago sativa L.), agronomic and environmental concerns mean that it is important to determine the N fertilizer contribution of this legume for subsequent crops in order to help to increase the sustainability of cropping systems. To determine the N fertilizer replacement value (FRV) of a 2-yr alfalfa crop on subsequent crops of corn (Zea mays L.) followed by wheat (Triticum aestivum L.) under irrigated Mediterranean conditions, two 4-yr rotations (alf...

Antifungal (Gaeumannomyces graminis var. tritici) activity of various glycosides of medicagenic acid

OpenAIRE

Stefan Martyniuk; Marian Jurzysta

2012-01-01

Different concentrations of medicagenic acid and five glycosides of this acid isolated from alfalfa (Medicago sativa) were added to agar medium (corn meal agar, CMA) inoculated with cultures of Gaeumannomyces graminis var. tritici (Ggt). After 7 days of incubation at 25oC colony radius was measured and % of inhibition calculated in relation to the control medium (CMA enriched with the solvent of the tested compounds). Within the tested concentrations, only 3-O-β -D -glucopiranoside medicagena...

Ultrastructural and Molecular Analyses Reveal Enhanced Nucleolar Activity in Medicago truncatula Cells Overexpressing the MtTdp2α Gene

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Macovei, Anca; Faè, Matteo; Biggiogera, Marco; de Sousa Araújo, Susana; Carbonera, Daniela; Balestrazzi, Alma

2018-01-01

The role of tyrosyl-DNA phosphodiesterase 2 (Tdp2) involved in the repair of 5′-end-blocking DNA lesions is still poorly explored in plants. To gain novel insights, Medicago truncatula suspension cultures overexpressing the MtTdp2α gene (Tdp2α-13C and Tdp2α-28 lines, respectively) and a control (CTRL) line carrying the empty vector were investigated. Transmission electron microscopy (TEM) revealed enlarged nucleoli (up to 44% expansion of the area, compared to CTRL), the presence of nucleolar vacuoles, increased frequency of multinucleolate cells (up to 4.3-fold compared to CTRL) and reduced number of ring-shaped nucleoli in Tdp2α-13C and Tdp2α-28 lines. Ultrastructural data suggesting for enhanced nucleolar activity in MtTdp2α-overexpressing lines were integrated with results from bromouridine incorporation. The latter revealed an increase of labeled transcripts in both Tdp2α-13C and Tdp2α-28 cells, within the nucleolus and in the extra-nucleolar region. MtTdp2α-overexpressing cells showed tolerance to etoposide, a selective inhibitor of DNA topoisomerase II, as evidenced by DNA diffusion assay. TEM analysis revealed etoposide-induced rearrangements within the nucleolus, resembling the nucleolar caps observed in animal cells under transcription impairment. Based on these findings it is evident that MtTdp2α-overexpression enhances nucleolar activity in plant cells. PMID:29868059

Ultrastructural and Molecular Analyses Reveal Enhanced Nucleolar Activity in Medicago truncatula Cells Overexpressing the MtTdp2α Gene

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Anca Macovei

2018-05-01

Full Text Available The role of tyrosyl-DNA phosphodiesterase 2 (Tdp2 involved in the repair of 5′-end-blocking DNA lesions is still poorly explored in plants. To gain novel insights, Medicago truncatula suspension cultures overexpressing the MtTdp2α gene (Tdp2α-13C and Tdp2α-28 lines, respectively and a control (CTRL line carrying the empty vector were investigated. Transmission electron microscopy (TEM revealed enlarged nucleoli (up to 44% expansion of the area, compared to CTRL, the presence of nucleolar vacuoles, increased frequency of multinucleolate cells (up to 4.3-fold compared to CTRL and reduced number of ring-shaped nucleoli in Tdp2α-13C and Tdp2α-28 lines. Ultrastructural data suggesting for enhanced nucleolar activity in MtTdp2α-overexpressing lines were integrated with results from bromouridine incorporation. The latter revealed an increase of labeled transcripts in both Tdp2α-13C and Tdp2α-28 cells, within the nucleolus and in the extra-nucleolar region. MtTdp2α-overexpressing cells showed tolerance to etoposide, a selective inhibitor of DNA topoisomerase II, as evidenced by DNA diffusion assay. TEM analysis revealed etoposide-induced rearrangements within the nucleolus, resembling the nucleolar caps observed in animal cells under transcription impairment. Based on these findings it is evident that MtTdp2α-overexpression enhances nucleolar activity in plant cells.

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

The structures of cytosolic and plastid-located glutamine synthetases from Medicago truncatula reveal a common and dynamic architecture

International Nuclear Information System (INIS)

Torreira, Eva; Seabra, Ana Rita; Marriott, Hazel; Zhou, Min; Llorca, Óscar; Robinson, Carol V.; Carvalho, Helena G.; Fernández-Tornero, Carlos; Pereira, Pedro José Barbosa

2014-01-01

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

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.

The bHLH Transcription Factors TSAR1 and TSAR2 Regulate Triterpene Saponin Biosynthesis in Medicago truncatula.

Science.gov (United States)

Mertens, Jan; Pollier, Jacob; Vanden Bossche, Robin; Lopez-Vidriero, Irene; Franco-Zorrilla, José Manuel; Goossens, Alain

2016-01-01

Plants respond to stresses by producing a broad spectrum of bioactive specialized metabolites. Hormonal elicitors, such as jasmonates, trigger a complex signaling circuit leading to the concerted activation of specific metabolic pathways. However, for many specialized metabolic pathways, the transcription factors involved remain unknown. Here, we report on two homologous jasmonate-inducible transcription factors of the basic helix-loop-helix family, TRITERPENE SAPONIN BIOSYNTHESIS ACTIVATING REGULATOR1 (TSAR1) and TSAR2, which direct triterpene saponin biosynthesis in Medicago truncatula. TSAR1 and TSAR2 are coregulated with and transactivate the genes encoding 3-HYDROXY-3-METHYLGLUTARYL-COENZYME A REDUCTASE1 (HMGR1) and MAKIBISHI1, the rate-limiting enzyme for triterpene biosynthesis and an E3 ubiquitin ligase that controls HMGR1 levels, respectively. Transactivation is mediated by direct binding of TSARs to the N-box in the promoter of HMGR1. In transient expression assays in tobacco (Nicotiana tabacum) protoplasts, TSAR1 and TSAR2 exhibit different patterns of transactivation of downstream triterpene saponin biosynthetic genes, hinting at distinct functionalities within the regulation of the pathway. Correspondingly, overexpression of TSAR1 or TSAR2 in M. truncatula hairy roots resulted in elevated transcript levels of known triterpene saponin biosynthetic genes and strongly increased the accumulation of triterpene saponins. TSAR2 overexpression specifically boosted hemolytic saponin biosynthesis, whereas TSAR1 overexpression primarily stimulated nonhemolytic soyasaponin biosynthesis. Both TSARs also activated all genes of the precursor mevalonate pathway but did not affect sterol biosynthetic genes, pointing to their specific role as regulators of specialized triterpene metabolism in M. truncatula. © 2016 American Society of Plant Biologists. All Rights Reserved.

A Medicago truncatula tobacco retrotransposon insertion mutant collection with defects in nodule development and symbiotic nitrogen fixation.

Science.gov (United States)

Pislariu, Catalina I; Murray, Jeremy D; Wen, JiangQi; Cosson, Viviane; Muni, RajaSekhara Reddy Duvvuru; Wang, Mingyi; Benedito, Vagner A; Andriankaja, Andry; Cheng, Xiaofei; Jerez, Ivone Torres; Mondy, Samuel; Zhang, Shulan; Taylor, Mark E; Tadege, Million; Ratet, Pascal; Mysore, Kirankumar S; Chen, Rujin; Udvardi, Michael K

2012-08-01

A Tnt1-insertion mutant population of Medicago truncatula ecotype R108 was screened for defects in nodulation and symbiotic nitrogen fixation. Primary screening of 9,300 mutant lines yielded 317 lines with putative defects in nodule development and/or nitrogen fixation. Of these, 230 lines were rescreened, and 156 lines were confirmed with defective symbiotic nitrogen fixation. Mutants were sorted into six distinct phenotypic categories: 72 nonnodulating mutants (Nod-), 51 mutants with totally ineffective nodules (Nod+ Fix-), 17 mutants with partially ineffective nodules (Nod+ Fix+/-), 27 mutants defective in nodule emergence, elongation, and nitrogen fixation (Nod+/- Fix-), one mutant with delayed and reduced nodulation but effective in nitrogen fixation (dNod+/- Fix+), and 11 supernodulating mutants (Nod++Fix+/-). A total of 2,801 flanking sequence tags were generated from the 156 symbiotic mutant lines. Analysis of flanking sequence tags revealed 14 insertion alleles of the following known symbiotic genes: NODULE INCEPTION (NIN), DOESN'T MAKE INFECTIONS3 (DMI3/CCaMK), ERF REQUIRED FOR NODULATION, and SUPERNUMERARY NODULES (SUNN). In parallel, a polymerase chain reaction-based strategy was used to identify Tnt1 insertions in known symbiotic genes, which revealed 25 additional insertion alleles in the following genes: DMI1, DMI2, DMI3, NIN, NODULATION SIGNALING PATHWAY1 (NSP1), NSP2, SUNN, and SICKLE. Thirty-nine Nod- lines were also screened for arbuscular mycorrhizal symbiosis phenotypes, and 30 mutants exhibited defects in arbuscular mycorrhizal symbiosis. Morphological and developmental features of several new symbiotic mutants are reported. The collection of mutants described here is a source of novel alleles of known symbiotic genes and a resource for cloning novel symbiotic genes via Tnt1 tagging.

Determination of Nutrient Contents and Gas Production Values of Some Legume Forages Grown in the Harran Plain Saline Soils

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M. Boga

2014-06-01

Full Text Available The aim of this study was to determine the nutritive value of some legume species in salt-affected soils of South-East Anatolian region using chemical composition and in vitro gas production kinetics. In this study, Lotus corniculatus, Trifolium alexandrinum, Medicago sativa were sown and tested in four different locations. A 3 by 4 factorial design with 3 legume species and 4 salt levels (non salty electrical conductivity (ECECECEC was used in the study. Results indicated that salinity and plants had no significant effect on ash and ether extract. Dry matter (DM, acid detergent fiber, digestible dry matter, dry matter intake (DMI were affected by plant, salinity and plant×salinity interaction. On the other hand neutral detergent fiber, relative feed value (RFV, and DMI were affected by salinity and plant×salinity interaction. Mineral contents were affected by plant species, salinity and salinity×plants interactions. In vitro gas production, their kinetics and estimated parameters such as were not affected by salinity whereas the gas production up to 48 h, organic matter digestibility, metabolizable energy (ME, and net energy lactation (NEL were affected by plant and plant×salt interaction. Generally RFVs of all species ranged from 120 to 210 and were quite satisfactory in salty conditions. Current results show that the feed value of Medicago sativa is higher compared to Lotus corniculatus and Trifolium alexandrinum.

PlantTribes: a gene and gene family resource for comparative genomics in plants

OpenAIRE

Wall, P. Kerr; Leebens-Mack, Jim; Müller, Kai F.; Field, Dawn; Altman, Naomi S.; dePamphilis, Claude W.

2007-01-01

The PlantTribes database (http://fgp.huck.psu.edu/tribe.html) is a plant gene family database based on the inferred proteomes of five sequenced plant species: Arabidopsis thaliana, Carica papaya, Medicago truncatula, Oryza sativa and Populus trichocarpa. We used the graph-based clustering algorithm MCL [Van Dongen (Technical Report INS-R0010 2000) and Enright et al. (Nucleic Acids Res. 2002; 30: 1575–1584)] to classify all of these species’ protein-coding genes into putative gene families, ca...

Gamma-Ray Doses Affected on Alfalfa (Medicago sativa L.)

International Nuclear Information System (INIS)

Zayed, E.M; Tarrad, M.M.; Abd El-Daem, G.A.N.A.

2013-01-01

Field experiments were conducted at the experimental from, Nuclear Research Center at Inshas. Atomic Energy Authority (AEA) at Egypt during 2011– 2012 growing seasons on alfalfa genotype. The aim of this investigation to evaluate the effect of different gamma ray doses (100-300 Gy) on the alfalfa yield and related traits. Seeds lots of alfalfa genotype were subjected to five gamma ray treatments (100,150,200,250 and 300 Gray). Over all cuts, the dose treatment 300 Gy increased the majority of studied traits i.e., plant height, No. of shoots/plant, fresh weight/plant, fresh yield/Fadden and dry weight yield/fed. The results observed indicated that. In addition, dose of 200 and 250 Gy increased No. of leaves /plant, No. of shoots/plant, stem diameter and fresh weight /plant. However, the plant dry weight was decreased by all doses used and over all cuts, but the dose of 100 and 150 Gy increased leaves /stem ratio. Meanwhile, the later cuts were more affected by irradiation treatments than the earlier ones. In general, the low doses had negative effects on yield traits, but, the relatively high doses exhibited an increase in yield traits

Studi tentang pola produksi alfalfa tropis (Medicago sativa L.

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Rini Dwi Wahyuni

2012-06-01

Full Text Available Abstract The research aims to determine the growth pattern of alfalfa in the tropical region, which later can be used as a source of information for the people needed. Research methods used are experimental; the data acquired during the 90 days was showed in a graph and then analyzed using regression analysis with two variables, namely independent variables (cutting age and dependent variables (the nutritive value, height of plants, and production of dry matter (DM, organic matter (OM, and crude protein (CP. The growth pattern of alfalfa in the range 20 to 90 days was quadratic, with the equation of y= -0.0092x2 + 1.6113x – 19.257. At that range of time the alfalfa was still in vegetative growth phase. With increasing age of cutting, the alfalfa chemical compositions of DM and OM increased, but the content of CP decreased.While the production of DM, OM, and CP increased with increasing cutting age. Key words: nutrition, growth, alfalfa, tropics

Evaluation of Selection Indices for Alfalfa (Medicago sativa L.

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Hassan MONIRIFAR

2010-03-01

Full Text Available In order to evaluate the efficiency of selection indices in alfalfa improvement, an experiment was conducted from 2000 to 2007 at East Azarbaijan Agricultural and Natural Resources Research Center, Iran. A set of 29 native ecotypes, which were collected in 2000 and 2001 from Azerbaijan (Iran, together with one improved variety were used to conduct a polycross nursery. For the purpose of random mating, a randomized complete block design was used with 12 replications arranged in this nursery. The resulting 30 half-sib families were planted individually in pots and the 30 days old seedlings were transplanted to the field in May, 2004. Each 3-row plot consisted of 45 HS plants. Several traits, such as individual plants� fresh weight and individual plants� dry weight (IPFW, IPDW, number of shoots per plant (NS and plant height (PH in each harvest and also, days until 10% flowering, the ratio of fresh and dry weight of leaves/plant and size of trifoliate leaves were measured for three cropping seasons. The results of analysis of variance showed large variation among polycross progenies. Six selection indices (Ii with different number of traits at adult plant stage were evaluated. Based on the result of this investigation, if number of shoots and height of adult plant, excluding yield, are recorded, I2 is suggested. If, in addition to fresh yield, height of adult plant is measured, I6 is recommended. I4 is useful when number of shoots and plant height with dry yield are included in the index. In conclusion, the importance of mature plant traits in selection indices was in the order of yield > plant height > number of shoots. The results provided more evidence that selection indices incorporating the component of dry yield are more advantageous. The most efficient selection index consisted of NS, IPDW and PH, having a relative efficiency of 280%.

Beneficial contribution of the arbuscular mycorrhizal fungus, Rhizophagus irregularis, in the protection of Medicago truncatula roots against benzo[a]pyrene toxicity.

Science.gov (United States)

Lenoir, Ingrid; Fontaine, Joël; Tisserant, Benoît; Laruelle, Frédéric; Lounès-Hadj Sahraoui, Anissa

2017-07-01

Arbuscular mycorrhizal fungi are able to improve plant establishment in polluted soils but little is known about the genes involved in the plant protection against pollutant toxicity by mycorrhization, in particular in the presence of polycyclic aromatic hydrocarbons (PAH). The present work aims at studying in both symbiotic partners, Medicago truncatula and Rhizophagus irregularis: (i) expression of genes putatively involved in PAH tolerance (MtSOD, MtPOX, MtAPX, MtGST, MtTFIIS, and MtTdp1α), (ii) activities of antioxidant (SOD, POX) and detoxification (GST) enzymes, and (iii) H 2 O 2 and the heavy PAH, benzo[a]pyrene (B[a]P) accumulation. In the presence of B[a]P, whereas induction of the enzymatic activities was detected in R. irregularis and non-mycorrhizal roots as well as upregulation of the gene expressions in the non-mycorrhizal roots, downregulation of the gene expressions and decrease of enzyme activities were observed in mycorrhizal roots. Moreover, B[a]P increased H 2 O 2 production in non-mycorrhizal roots and in R. irregularis but not in mycorrhizal roots. In addition, a lower B[a]P bioaccumulation in mycorrhizal roots was measured in comparison with non-mycorrhizal roots. Being less affected by pollutant toxicity, mycorrhizal roots did not activate any defense mechanism either at the gene expression regulation level or at the enzymatic level.

A Medicago truncatula H+-pyrophosphatase gene, MtVP1, improves sucrose accumulation and anthocyanin biosynthesis in potato (Solanum tuberosum L.).

Science.gov (United States)

Wang, J W; Wang, H Q; Xiang, W W; Chai, T Y

2014-05-09

We recently cloned MtVP1, a type I vacuolar-type H(+)-translocating inorganic pyrophosphatase from Medicago truncatula. In the present study, we investigated the cellular location and the function of this H(+)-PPase in Arabidopsis and potato (Solanum tuberosum L.). An MtVP1::enhanced green fluorescent protein fusion was constructed, which localized to the plasma membrane of onion epidermal cells. Transgenic Arabidopsis thaliana overexpressing MtVP1 had more robust root systems and redder shoots than wild-type (WT) plants under conditions of cold stress. Furthermore, overexpression of MtVP1 in potato accelerated the formation and growth of vegetative organs. The tuber buds and stem base of transgenic potatoes became redder than those of WT plants, but flowering was delayed by approximately half a month. Interestingly, anthocyanin biosynthesis was promoted in transgenic Arabidopsis seedlings and potato tuber buds. The sucrose concentration of transgenic potato tubers and tuber buds was enhanced compared with that of WT plants. Furthermore, sucrose concentration in tubers was higher than that in tuber buds. Although there was no direct evidence to support Fuglsang's hypothetical model regarding the effects of H(+)-PPase on sucrose phloem loading, we speculated that sucrose concentration was increased in tuber buds owing to the increased concentration in tubers. Therefore, overexpressed MtVP1 enhanced sucrose accumulation of source organs, which might enhance sucrose transport to sink organs, thus affecting anthocyanin biosynthesis.

AFLP and AMP Fingerprints as Markers to Evaluate Genetic Differences between Medicago truncatula Line Jemalong and 2HA, a New Line Produced by in vitro Culture Selection

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R.R. Irwanto

2008-09-01

Full Text Available A new line, Medicago truncatula cv. Jemalong 2HA (herein known as 2HA has been developed via repetitive regeneration and selection of M. truncatula cv. Jemalong. During somatic embryogenesis, 2HA produces 500 times more embryos than its progenitor, Jemalong. It is interesting to study if those two lines are isogenic or has genetic differences. The main objectives of the study was to evaluate the genotypic differences between Jemalong and 2HA also to evaluate the methylation event in 2HA utilized two DNA fingerprinting techniques, i.e AFLP fingerprints (Amplified Length of Polymorphism and AMP (Amplified Methylation Polymorphism. The results showed that AFLP analysis using eight primers combinations could not detect any differences between Jemalong and 2HA. However, using AMP methylation sensitive primers it could detect 15 polymorphisms out of 840 markers. These results lead to a conclusion that Jemalong and 2HA are isogenic lines. 2HA may have higher regeneration capacities due to methylation process which occurs during the production of 2HA through repetitive regeneration cycles.

Medicago truncatula DNF2 is a PI-PLC-XD-containing protein required for bacteroid persistence and prevention of nodule early senescence and defense-like reactions.

Science.gov (United States)

Bourcy, Marie; Brocard, Lysiane; Pislariu, Catalina I; Cosson, Viviane; Mergaert, Peter; Tadege, Millon; Mysore, Kirankumar S; Udvardi, Michael K; Gourion, Benjamin; Ratet, Pascal

2013-03-01

Medicago truncatula and Sinorhizobium meliloti form a symbiotic association resulting in the formation of nitrogen-fixing nodules. Nodule cells contain large numbers of bacteroids which are differentiated, nitrogen-fixing forms of the symbiotic bacteria. In the nodules, symbiotic plant cells home and maintain hundreds of viable bacteria. In order to better understand the molecular mechanism sustaining the phenomenon, we searched for new plant genes required for effective symbiosis. We used a combination of forward and reverse genetics approaches to identify a gene required for nitrogen fixation, and we used cell and molecular biology to characterize the mutant phenotype and to gain an insight into gene function. The symbiotic gene DNF2 encodes a putative phosphatidylinositol phospholipase C-like protein. Nodules formed by the mutant contain a zone of infected cells reduced to a few cell layers. In this zone, bacteria do not differentiate properly into bacteroids. Furthermore, mutant nodules senesce rapidly and exhibit defense-like reactions. This atypical phenotype amongst Fix(-) mutants unravels dnf2 as a new actor of bacteroid persistence inside symbiotic plant cells. © 2012 CNRS. New Phytologist © 2012 New Phytologist Trust.

Symbiosis between nitrogen-fixing bacteria and Medicago truncatula is not significantly affected by silver and silver sulfide nanomaterials.

Science.gov (United States)

Judy, Jonathan D; Kirby, Jason K; McLaughlin, Mike J; McNear, David; Bertsch, Paul M

2016-07-01

Silver (Ag) engineered nanomaterials (ENMs) are being released into waste streams and are being discharged, largely as Ag2S aged-ENMs (a-ENMs), into agroecosystems receiving biosolids amendments. Recent research has demonstrated that biosolids containing an environmentally relevant mixture of ZnO, TiO2, and Ag ENMs and their transformation products, including Ag2S a-ENMs, disrupted the symbiosis between nitrogen-fixing bacteria and legumes. However, this study was unable to unequivocally determine which ENM or combination of ENMs and a-ENMs was responsible for the observed inhibition. Here, we examined further the effects of polyvinylpyrollidone (PVP) coated pristine Ag ENMs (PVP-Ag), Ag2S a-ENMs, and soluble Ag (as AgSO4) at 1, 10, and 100 mg Ag kg(-1) on the symbiosis between the legume Medicago truncatula and the nitrogen-fixing bacterium, Sinorhizobium melliloti in biosolids-amended soil. Nodulation frequency, nodule function, glutathione reductase production, and biomass were not significantly affected by any of the Ag treatments, even at 100 mg kg(-1), a concentration analogous to a worst-case scenario resulting from long-term, repeated biosolids amendments. Our results provide additional evidence that the disruption of the symbiosis between nitrogen-fixing bacteria and legumes in response to a mixture of ENMs in biosolids-amended soil reported previously may not be attributable to Ag ENMs or their transformation end-products. We anticipate these findings will provide clarity to regulators and industry regarding potential unintended consequences to terrestrial ecosystems resulting from of the use of Ag ENMs in consumer products. Copyright © 2016 Elsevier Ltd. All rights reserved.

Dicty_cDB: FC-BN21 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available BC26G02 of cDNA library MtBC from arbuscular mycorrhiza of cultivar Jemalong of Medicago truncatula (barrel ...ead. 56 6e-04 1 AL384688 |AL384688.1 Medicago truncatula EST MtBC23G08F1 : T3 end of clone MtBC23G08 of cDNA library MtBC from arbusc...ular mycorrhiza of cultivar Jemalong of Medicago truncat

Analysis of Large Seeds from Three Different Medicago truncatula Ecotypes Reveals a Potential Role of Hormonal Balance in Final Size Determination of Legume Grains

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Kaustav Bandyopadhyay

2016-09-01

Full Text Available Legume seeds are important as protein and oil source for human diet. Understanding how their final seed size is determined is crucial to improve crop yield. In this study, we analyzed seed development of three accessions of the model legume, Medicago truncatula, displaying contrasted seed size. By comparing two large seed accessions to the reference accession A17, we described mechanisms associated with large seed size determination and potential factors modulating the final seed size. We observed that early events during embryogenesis had a major impact on final seed size and a delayed heart stage embryo development resulted to large seeds. We also observed that the difference in seed growth rate was mainly due to a difference in embryo cell number, implicating a role of cell division rate. Large seed accessions could be explained by an extended period of cell division due to a longer embryogenesis phase. According to our observations and recent reports, we observed that auxin (IAA and abscisic acid (ABA ratio could be a key determinant of cell division regulation at the end of embryogenesis. Overall, our study highlights that timing of events occurring during early seed development play decisive role for final seed size determination.

Loss of the nodule-specific cysteine rich peptide, NCR169, abolishes symbiotic nitrogen fixation in the Medicago truncatula dnf7 mutant.

Science.gov (United States)

Horváth, Beatrix; Domonkos, Ágota; Kereszt, Attila; Szűcs, Attila; Ábrahám, Edit; Ayaydin, Ferhan; Bóka, Károly; Chen, Yuhui; Chen, Rujin; Murray, Jeremy D; Udvardi, Michael K; Kondorosi, Éva; Kaló, Péter

2015-12-08

Host compatible rhizobia induce the formation of legume root nodules, symbiotic organs within which intracellular bacteria are present in plant-derived membrane compartments termed symbiosomes. In Medicago truncatula nodules, the Sinorhizobium microsymbionts undergo an irreversible differentiation process leading to the development of elongated polyploid noncultivable nitrogen fixing bacteroids that convert atmospheric dinitrogen into ammonia. This terminal differentiation is directed by the host plant and involves hundreds of nodule specific cysteine-rich peptides (NCRs). Except for certain in vitro activities of cationic peptides, the functional roles of individual NCR peptides in planta are not known. In this study, we demonstrate that the inability of M. truncatula dnf7 mutants to fix nitrogen is due to inactivation of a single NCR peptide, NCR169. In the absence of NCR169, bacterial differentiation was impaired and was associated with early senescence of the symbiotic cells. Introduction of the NCR169 gene into the dnf7-2/NCR169 deletion mutant restored symbiotic nitrogen fixation. Replacement of any of the cysteine residues in the NCR169 peptide with serine rendered it incapable of complementation, demonstrating an absolute requirement for all cysteines in planta. NCR169 was induced in the cell layers in which bacteroid elongation was most pronounced, and high expression persisted throughout the nitrogen-fixing nodule zone. Our results provide evidence for an essential role of NCR169 in the differentiation and persistence of nitrogen fixing bacteroids in M. truncatula.

Effect of Rhizosphere Enzymes on Phytoremediation in PAH-Contaminated Soil Using Five Plant Species

Science.gov (United States)

Liu, Rui; Dai, Yuanyuan; Sun, Libo

2015-01-01

A pot experiment was performed to study the effectiveness of remediation using different plant species and the enzyme response involved in remediating PAH-contaminated soil. The study indicated that species Echinacea purpurea, Festuca arundinacea Schred, Fire Phoenix (a combined F. arundinacea), and Medicago sativa L. possess the potential for remediation in PAH-contaminated soils. The study also determined that enzymatic reactions of polyphenol oxidase (except Fire Phoenix), dehydrogenase (except Fire Phoenix), and urease (except Medicago sativa L.) were more prominent over cultivation periods of 60d and 120d than 150d. Urease activity of the tested species exhibited prominently linear negative correlations with alkali-hydrolyzable nitrogen content after the tested plants were cultivated for 150d (R2 = 0.9592). The experiment also indicated that alkaline phosphatase activity in four of the five tested species (Echinacea purpurea, Callistephus chinensis, Festuca arundinacea Schred and Fire Phoenix) was inhibited during the cultivation process (at 60d and 120d). At the same time, the study determined that the linear relationship between alkaline phosphatase activity and effective phosphorus content in plant rhizosphere soil exhibited a negative correlation after a growing period of 120d (R2 = 0.665). Phytoremediation of organic contaminants in the soil was closely related to specific characteristics of particular plant species, and the catalyzed reactions were the result of the action of multiple enzymes in the plant rhizosphere soil. PMID:25822167

Local and distal effects of arbuscular mycorrhizal colonization on direct pathway Pi uptake and root growth in Medicago truncatula

Science.gov (United States)

Watts-Williams, Stephanie J.; Jakobsen, Iver; Cavagnaro, Timothy R.; Grønlund, Mette

2015-01-01

Two pathways exist for plant Pi uptake from soil: via root epidermal cells (direct pathway) or via associations with arbuscular mycorrhizal (AM) fungi, and the two pathways interact in a complex manner. This study investigated distal and local effects of AM colonization on direct root Pi uptake and root growth, at different soil P levels. Medicago truncatula was grown at three soil P levels in split-pots with or without AM fungal inoculation and where one root half grew into soil labelled with 33P. Plant genotypes included the A17 wild type and the mtpt4 mutant. The mtpt4 mutant, colonized by AM fungi, but with no functional mycorrhizal pathway for Pi uptake, was included to better understand effects of AM colonization per se. Colonization by AM fungi decreased expression of direct Pi transporter genes locally, but not distally in the wild type. In mtpt4 mutant plants, direct Pi transporter genes and the Pi starvation-induced gene Mt4 were more highly expressed than in wild-type roots. In wild-type plants, less Pi was taken up via the direct pathway by non-colonized roots when the other root half was colonized by AM fungi, compared with non-mycorrhizal plants. Colonization by AM fungi strongly influenced root growth locally and distally, and direct root Pi uptake activity locally, but had only a weak influence on distal direct pathway activity. The responses to AM colonization in the mtpt4 mutant suggested that in the wild type, the increased P concentration of colonized roots was a major factor driving the effects of AM colonization on direct root Pi uptake. PMID:25944927

Chemotaxonomy of the genus Stemphylium

DEFF Research Database (Denmark)

Olsen, Kresten Jon Kromphardt; Andersen, Birgitte

2016-01-01

The filamentous fungal genus Stemphylium (Anamophic Pleospora) is often found on various crops, and especially the common animal feed plant Medicago sativa (alfalfa) is often infected by this plant pathogen. With this in mind it is important to consider what consequences such a contamination can...... have, e.g. production of mycotoxins. (Firsvad et al. (2009)) A clade of Stemphylium spp. i.e. S. herbarum, S. alfalfae, S. sedicola, S. tomatonis and S. vesicariumare troublesome to distinguish as they share both morphological and molecular characteristics. This study has focused on using chemotaxonomy...

Evaluation for dinitrogen fixation of alfalfa in field based on δ15N value

International Nuclear Information System (INIS)

Yao Yunyin; Chen Ming; Zhang Xizhong

1992-12-01

The dinitrogen fixation rate of alfalfa was estimated grown in pot and field experiments. β values (isotope fraction factor) of 7 cultivars of alfalfa (Medicago sativa L.) and white clover (Trifolium repens L.) grown in N-free liquid culture medium were examined. Variations in the δ 15 N values of varieties of alfalfa at growing seasons and forage grasses grown under various conditions were measured. %Ndfa of alfalfa was estimated using the natural 15 N abundance method, 15 N isotope dilution method and total N difference, and their accuracy was compared

Analysis of Ag nanoparticles synthesized by bioreduction.

Science.gov (United States)

Tavera-Davila, L; Liu, H B; Herrera-Becerra, R; Canizal, G; Balcazar, M; Ascencio, J A

2009-03-01

Based on a green chemistry mechanism, small silver clusters were obtained by using biosynthesis with alfalfa (medicago sativa), controlling the size of the nanoparticles base don different pH conditions. The analysis of the samples was made with help of transmission electron microscopy methods, mainly with high angle annular dark field and high resolution transmission electron microscopy. The optimal conditions were identified when the sample was obtained at pH10, which allowed obtaining an average size of 4.09 nm and a standard deviation of 1.59, mainly based on cubic like structures.

Effects of agrochemical measures on plutonium 239,240 and americium 24 accumulation in some legume plants

International Nuclear Information System (INIS)

Budkevich, T.A.; Zabolotnyj, A.I.; Kudryashov, V.P.

2002-01-01

During 1998-2000 in field experiments at territories contaminated with transuranic elements (TUE) the mineral fertilizers were studied as means of decreasing the TUE accumulation in legume plants ( Lupinus luteus L., Lupinus angustifolius L., Trifolium pratense L., Medicago sativa L.). Under the action of lime Pu 239, 240 and Am 241 accumulation in green parts and seeds of Lupinus decreased in 1,5-5 times, and in overground mass of legume grasses in 1,5-2,5 times. The combined action of PK-fertilizes and lime didn't decrease TUE transfer into legume plants

Genome-wide identification and characterization of stress-associated protein (SAP gene family encoding A20/AN1 zinc-finger proteins in Medicago truncatula

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Zhou Yong

2018-01-01

Full Text Available Stress associated proteins (SAPs play important roles in developmental processes, responses to various stresses and hormone stimulation in plants. However, little is known about the SAP gene family in Medicago truncatula. In this study, a total of 17 MtSAP genes encoding A20/AN1 zinc-finger proteins were characterized. Out of these 17 genes, 15 were distributed over all 8 chromosomes at different densities, and two segmental duplication events were detected. The phylogenetic analysis of these proteins and their orthologs from Arabidopsis and rice suggested that they could be classified into five out of the seven groups of SAP family genes, with genes in the same group showing similar structures and conserved domains. The cis-elements of the MtSAP promoters were studied, and many cis-elements related to stress and plant hormone responses were identified. We also investigated the stress-responsive expression patterns of the MtSAP genes under various stresses, including drought, exposure to NaCl and cold. The qRT-PCR results showed that numerous MtSAP genes exhibited transcriptional responses to multiple abiotic stresses. These results lay the foundation for further functional characterization of SAP genes. To the best of our knowledge, this is the first report of a genome-wide analysis of the SAP gene family in M. truncatula.

Overexpression of a Medicago truncatula stress-associated protein gene (MtSAP1) leads to nitric oxide accumulation and confers osmotic and salt stress tolerance in transgenic tobacco.

Science.gov (United States)

Charrier, Aurélie; Planchet, Elisabeth; Cerveau, Delphine; Gimeno-Gilles, Christine; Verdu, Isabelle; Limami, Anis M; Lelièvre, Eric

2012-08-01

The impact of Medicago truncatula stress-associated protein gene (MtSAP1) overexpression has been investigated in Nicotiana tabacum transgenic seedlings. Under optimal conditions, transgenic lines overexpressing MtSAP1 revealed better plant development and higher chlorophyll content as compared to wild type seedlings. Interestingly, transgenic lines showed a stronger accumulation of nitric oxide (NO), a signaling molecule involved in growth and development processes. This NO production seemed to be partially nitrate reductase dependent. Due to the fact that NO has been also reported to play a role in tolerance acquisition of plants to abiotic stresses, the responses of MtSAP1 overexpressors to osmotic and salt stress have been studied. Compared to the wild type, transgenic lines were less affected in their growth and development. Moreover, NO content in MtSAP1 overexpressors was always higher than that detected in wild seedlings under stress conditions. It seems that this better tolerance induced by MtSAP1 overexpression could be associated with this higher NO production that would enable seedlings to reach a high protection level to prepare them to cope with abiotic stresses.

Identification of the large subunit of Ribulose 1,5-bisphosphate carboxylase/oxygenase as a substrate for transglutaminase in Medicageo sativa L. (alfalfa)

International Nuclear Information System (INIS)

Margosiak, S.A.; Dharma, A.; Carver, M.R.B.; Gonzales, A.P.; Louie, D.; Kuehn, G.D.

1990-01-01

Extract prepared from floral meristematic tissue of alfalfa (Medicago sativa L.) were investigated for expression of the enzyme transglutaminase in order to identify the major protein substrate for transglutaminase-directed modifications among plant proteins. The large polymorphic subunits of ribulose 1,5-bisphosphate carboxylase/oxygenase in alfalfa, with molecular weights of 52,700 and 57,600, are major substrates for transglutaminase in these extracts. This was established by: (a) covalent conjugation of monodansylcadaverine to the large subunit followed by fluorescent detection in SDS-polyacrylamide gels; (b) covalent conjugation of [ 14 C]putrescine to the large subunit with detection by autoradiography; (c) covalent conjugation of monodansylcadaverine to the large subunit and demonstration of immunocross-reactivity on nitrocellulose transblot of the modified large subunit with antibody prepared in rabbits against dansylated-ovalbumin; (d) demonstration of a direct dependence of the rate of transglutaminase-mediated, [ 14 C]putresciene incorporation upon the concentration of ribulose, 1,5-bisphosphate carboxylase/oxygenase from alfalfa or spinach; and (e) presumptive evidence from size exclusion chromatography that transglutaminase may cofractionate with native molecules of ribulose 1,5-bisphosphate carboxylase/oxygenase in crude extracts

NAD1 Controls Defense-Like Responses in Medicago truncatula Symbiotic Nitrogen Fixing Nodules Following Rhizobial Colonization in a BacA-Independent Manner

Science.gov (United States)

Domonkos, Ágota; Kovács, Szilárd; Gombár, Anikó; Kiss, Ernő; Horváth, Beatrix; Kováts, Gyöngyi Z.; Farkas, Attila; Tóth, Mónika T.; Ayaydin, Ferhan; Bóka, Károly; Fodor, Lili; Endre, Gabriella; Kaló, Péter

2017-01-01

Legumes form endosymbiotic interaction with host compatible rhizobia, resulting in the development of nitrogen-fixing root nodules. Within symbiotic nodules, rhizobia are intracellularly accommodated in plant-derived membrane compartments, termed symbiosomes. In mature nodule, the massively colonized cells tolerate the existence of rhizobia without manifestation of visible defense responses, indicating the suppression of plant immunity in the nodule in the favur of the symbiotic partner. Medicago truncatula DNF2 (defective in nitrogen fixation 2) and NAD1 (nodules with activated defense 1) genes are essential for the control of plant defense during the colonization of the nitrogen-fixing nodule and are required for bacteroid persistence. The previously identified nodule-specific NAD1 gene encodes a protein of unknown function. Herein, we present the analysis of novel NAD1 mutant alleles to better understand the function of NAD1 in the repression of immune responses in symbiotic nodules. By exploiting the advantage of plant double and rhizobial mutants defective in establishing nitrogen-fixing symbiotic interaction, we show that NAD1 functions following the release of rhizobia from the infection threads and colonization of nodule cells. The suppression of plant defense is self-dependent of the differentiation status of the rhizobia. The corresponding phenotype of nad1 and dnf2 mutants and the similarity in the induction of defense-associated genes in both mutants suggest that NAD1 and DNF2 operate close together in the same pathway controlling defense responses in symbiotic nodules. PMID:29240711

NAD1 Controls Defense-Like Responses in Medicago truncatula Symbiotic Nitrogen Fixing Nodules Following Rhizobial Colonization in a BacA-Independent Manner

Directory of Open Access Journals (Sweden)

Ágota Domonkos

2017-12-01

Full Text Available Legumes form endosymbiotic interaction with host compatible rhizobia, resulting in the development of nitrogen-fixing root nodules. Within symbiotic nodules, rhizobia are intracellularly accommodated in plant-derived membrane compartments, termed symbiosomes. In mature nodule, the massively colonized cells tolerate the existence of rhizobia without manifestation of visible defense responses, indicating the suppression of plant immunity in the nodule in the favur of the symbiotic partner. Medicago truncatula DNF2 (defective in nitrogen fixation 2 and NAD1 (nodules with activated defense 1 genes are essential for the control of plant defense during the colonization of the nitrogen-fixing nodule and are required for bacteroid persistence. The previously identified nodule-specific NAD1 gene encodes a protein of unknown function. Herein, we present the analysis of novel NAD1 mutant alleles to better understand the function of NAD1 in the repression of immune responses in symbiotic nodules. By exploiting the advantage of plant double and rhizobial mutants defective in establishing nitrogen-fixing symbiotic interaction, we show that NAD1 functions following the release of rhizobia from the infection threads and colonization of nodule cells. The suppression of plant defense is self-dependent of the differentiation status of the rhizobia. The corresponding phenotype of nad1 and dnf2 mutants and the similarity in the induction of defense-associated genes in both mutants suggest that NAD1 and DNF2 operate close together in the same pathway controlling defense responses in symbiotic nodules.

Elevated CO2 increases R gene-dependent resistance of Medicago truncatula against the pea aphid by up-regulating a heat shock gene.

Science.gov (United States)

Sun, Yucheng; Guo, Huijuan; Yuan, Erliang; Ge, Feng

2018-03-01

Resistance against pathogens and herbivorous insects in many plant results from the expression of resistance (R) genes. Few reports, however, have considered the effects of elevated CO 2 on R gene-based resistance in plants. The current study determined the responses of two near isogenic Medicago truncatula genotypes (Jester has an R gene and A17 does not) to the pea aphid and elevated CO 2 in open-top chambers in the field. Aphid abundance, mean relative growth rate and feeding efficiency were increased by elevated CO 2 on A17 plants but were reduced on Jester plants. According to proteomic and gene expression data, elevated CO 2 enhanced pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) but decreased the effector-triggered immunity (ETI) in aphid-infested A17 plants. For aphid-infested Jester plants, by contrast, elevated CO 2 enhanced the ETI-related heat shock protein (HSP) 90 and its co-chaperones, the jasmonic acid (JA) signaling pathway, and ubiquitin-mediated proteolysis. In a loss-of-function experiment, silencing of the HSP90 gene in Jester plants impaired the JA signaling pathway and ubiquitin-mediated proteolysis against the aphid under ambient CO 2 , and negated the increased resistance against the aphid under elevated CO 2 . Our results suggest that increases in expression of HSP90 are responsible for the enhanced resistance against the aphid under elevated CO 2 . © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

NAD1 Controls Defense-Like Responses in Medicago truncatula Symbiotic Nitrogen Fixing Nodules Following Rhizobial Colonization in a BacA-Independent Manner.

Science.gov (United States)

Domonkos, Ágota; Kovács, Szilárd; Gombár, Anikó; Kiss, Ernő; Horváth, Beatrix; Kováts, Gyöngyi Z; Farkas, Attila; Tóth, Mónika T; Ayaydin, Ferhan; Bóka, Károly; Fodor, Lili; Ratet, Pascal; Kereszt, Attila; Endre, Gabriella; Kaló, Péter

2017-12-14

Legumes form endosymbiotic interaction with host compatible rhizobia, resulting in the development of nitrogen-fixing root nodules. Within symbiotic nodules, rhizobia are intracellularly accommodated in plant-derived membrane compartments, termed symbiosomes. In mature nodule, the massively colonized cells tolerate the existence of rhizobia without manifestation of visible defense responses, indicating the suppression of plant immunity in the nodule in the favur of the symbiotic partner. Medicago truncatula DNF2 (defective in nitrogen fixation 2) and NAD1 (nodules with activated defense 1) genes are essential for the control of plant defense during the colonization of the nitrogen-fixing nodule and are required for bacteroid persistence. The previously identified nodule-specific NAD1 gene encodes a protein of unknown function. Herein, we present the analysis of novel NAD1 mutant alleles to better understand the function of NAD1 in the repression of immune responses in symbiotic nodules. By exploiting the advantage of plant double and rhizobial mutants defective in establishing nitrogen-fixing symbiotic interaction, we show that NAD1 functions following the release of rhizobia from the infection threads and colonization of nodule cells. The suppression of plant defense is self-dependent of the differentiation status of the rhizobia. The corresponding phenotype of nad1 and dnf2 mutants and the similarity in the induction of defense-associated genes in both mutants suggest that NAD1 and DNF2 operate close together in the same pathway controlling defense responses in symbiotic nodules.

Modeling of desorption of Alfalfa (Medicago sativa) stems and leaves.

NARCIS (Netherlands)

ArabHosseini, A.; Huisman, W.; Müller, J.

2011-01-01

The equilibrium moisture content of agricultural products is necessary to optimize drying process and helps to keep the quality of the product during the period of storage. The main aim of this research was to find the best model which could define well, the exchange of moisture between alfalfa

The effect of lucerne ( Medicago sativa ) hay quality on milk ...

African Journals Online (AJOL)

The influence of lucerne hay quality on the milk production potential and milk composition of Jersey cows was investigated. Three different grades of lucerne hay (Prime, Grade 1, Grade 2; selected according to the New Lucerne Quality Index) were included in a total mixed ration (TMR) and fed to lactating cows. The three ...

Metabolic responses of alfalfa (Medicago Sativa L.) leaves to low ...

African Journals Online (AJOL)

user

2011-02-14

Feb 14, 2011 ... and relative water content (RWC) in leaves under low and high temperature ... age of its supply as pasture, thus affecting development ..... te leak ag e (%. ) ) A. B. Figure 3. Effects of LT and HT stresses on MDA content and ...

The effect of lucerne (Medicago sativa) hay quality on milk ...

African Journals Online (AJOL)

Van Zyl, Marike

2014-08-23

Aug 23, 2014 ... 46th Congress of the South African Society for Animal Science ... After a dietary adaptation period of 14 days, each treatment received ... as the primary roughage source, was the best parameter to predict potential milk yield.

Sample preparation of Medicago sativa L. hay for chemical analysis

African Journals Online (AJOL)

UFS Campus

wavelength region (De Boever et al., 1996; Williams & Norris, 2001). Therefore, it could affect the predicted results of all the other parameters (CP, ADF, NDF, etc.). The grinding ... (September 2006 to May 2007). The samples represented lots that were selected at different stages of maturity. A moisture range as broad as ...

Dicty_cDB: FC-BN14 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available of cDNA library MtBC from arbuscular mycorrhiza of cultivar Jemalong of Medicago...clone MtBC26G02 of cDNA library MtBC from arbuscular mycorrhiza of cultivar Jemalong of Medicago truncatula

Dicty_cDB: FC-IC0586 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available 1 Medicago truncatula EST MtBC26G02F1 : T3 end of clone MtBC26G02 of cDNA library MtBC from arbuscular mycor...4688 |AL384688.1 Medicago truncatula EST MtBC23G08F1 : T3 end of clone MtBC23G08 of cDNA library MtBC from arbuscular...689.1 Medicago truncatula EST MtBC23G08R1 : T7 end of clone MtBC23G08 of cDNA library MtBC from arbuscular

Differential Effects of Legume Species on the Recovery of Soil Microbial Communities, and Carbon and Nitrogen Contents, in Abandoned Fields of the Loess Plateau, China

Science.gov (United States)

Li, Jin Hua; Jiao, Shu Mei; Gao, Rong Qing; Bardgett, Richard D.

2012-12-01

Plant-soil interactions are known to influence a wide range of ecosystem-level functions. Moreover, the recovery of these functions is of importance for the successful restoration of soils that have been degraded through intensive and/or inappropriate land use. Here, we assessed the effect of planting treatments commonly used to accelerate rates of grassland restoration, namely introduction of different legume species Medicago sativa, Astragalus adsurgens, Melilotus suaveolens, on the recovery of soil microbial communities and carbon and nitrogen contents in abandoned fields of the Loess Plateau, China. The results showed effects were species-specific, and either positive, neutral or negative depending on the measure and time-scale. All legumes increased basal respiration and metabolic quotient and had a positive effect on activity and functional diversity of the soil microbial community, measured using Biolog EcoPlate. However, soil under Astragalus adsurgens had the highest activity and functional diversity relative to the other treatments. Soil carbon and nitrogen content and microbial biomass were effectively restored in 3-5 years by introducing Medicago sativa and Astragalus adsurgens into early abandoned fields. Soil carbon and nitrogen content were retarded in 3-5 years and microbial biomass was retarded in the fifth year by introducing Melilotus suaveolens. Overall, the restoration practices of planting legumes can significantly affect soil carbon and nitrogen contents, and the biomass, activity, and functional diversity of soil microbial community. Therefore, we propose certain legume species could be used to accelerate ecological restoration of degraded soils, hence assist in the protection and preservation of the environment.

Quantitative 3-dimensional imaging of auxin and cytokinin levels in transgenic soybean and medicago truncatula roots via two-photon induced fluorescence imaging

Science.gov (United States)

Fisher, Jon; Gaillard, Paul; Nurmalasari, Ni Putu Dewi; Fellbaum, Carl; Subramaniam, Sen; Smith, Steve

2018-02-01

Industrial nitrogen fertilizers account for nearly 50% of the fossil fuel costs in modern agriculture and contribute to soil and water pollution. Therefore, significant interest exists in understanding and characterizing the efficiency of nitrogen fixation, and the biochemical signaling pathways which orchestrate the plant-microbial symbiosis through which plants fix nitrogen. Legume plant species exhibit a particularly efficient nitrogen uptake mechanism, using root nodules which house nitrogen-fixing rhizobial bacteria. While nodule development has been widely studied, there remain significant gaps in understanding the regulatory hormones' role in plant development. In this work, we produce 3-dimensional maps of auxin (AX) and cytokinin (CK) hormone concentrations within model plant root tips and nodules with respect to root architecture and cell type. Soybean and Medicago plants were transfected with a two-color fluorescent vector with AXsensitive green fluorescent protein (GFP) and CK-sensitive TdTomato (TdT). 3D images of soybean root nodules were captured using two-photon induced fluorescence microscopy. The resulting images were computationally analyzed using the localization code first developed by Weeks and later adapted by Kilfoil, and analyzed in the context of the root architecture. Statistical analysis of the resulting 3D hormone level maps reproduce-well the known roles of AX and CK in developing plant roots, and are the first quantitative description of these regulatory hormones tied to specific plant architecture. The analytical methods used, and the spatial distribution of these key regulatory hormones in plant roots, nodule primordia and root nodules, and their statistical interpretation are presented.

Identification of distinct quantitative trait loci associated with defence against the closely related aphids Acyrthosiphon pisum and A. kondoi in Medicago truncatula

KAUST Repository

Guo, Su-Min

2012-03-21

Aphids are a major family of plant insect pests. Medicago truncatula and Acyrthosiphon pisum (pea aphid, PA) are model species with a suite of resources available to help dissect the mechanism underlying plant-aphid interactions. A previous study focused on monogenic and relatively strong resistance in M. truncatula to PA and other aphid species. In this study a moderate resistance to PA was characterized in detail in the M. truncatula line A17 and compared with the highly susceptible line A20 and the more resistant line Jester. The results show that PA resistance in A17 involves both antibiosis and tolerance, and that resistance is phloem based. Quantitative trait locus (QTL) analysis using a recombinant inbred line (RIL) population (n=114) from a cross between A17 and A20 revealed that one locus, which co-segregated with AIN (Acyrthosiphon-induced necrosis) on chromosome 3, is responsible for the reduction of aphid biomass (indicator of antibiosis) for both PA and bluegreen aphid (BGA, A. kondoi), albeit to a lesser degree for PA than BGA. Interestingly, two independent loci on chromosomes 5 and 3 were identified for the plant biomass reduction (indicator of plant tolerance) by PA and BGA, respectively, demonstrating that the plant\\'s tolerance response to these two closely related aphid species is distinct. Together with previously identified major resistant (R) genes, the QTLs identified in this study are powerful tools to understand fully the spectrum of plant defence against sap-sucking insects and provide opportunities for breeders to generate effective and sustainable strategies for aphid control. 2012 The Author.

NaCl - Changes stem morphology, anatomy and phloem structure in Lucerne (Medicago sativa cv. Gabès): Comparison of upper and lower internodes.

Science.gov (United States)

Nja, Riheb Ben; Merceron, Bruno; Faucher, Mireille; Fleurat-Lessard, Pierrette; Béré, Emile

2018-02-01

In M. sativa cv. Gabès plants treated with 150mM NaCl, the height of the stem is decreased and the internode number, length and diameter are reduced. This depressive effect on growth, but also on photosynthetic activity and water balance, is accompanied by structural changes. In the upper internodes, NaCl treatment increases cambium development, so that the vascular ring is initiated earlier than in controls. In the lower internodes, the number of lignified phloem fibers is increased by NaCl, and their wall thickness is augmented, compared to controls; in the phloem complex, the nacreous layer is enlarged, the number of internal wall ingrowths is increased, but companion cells are damaged. In the treated lower internodes, few vessels occur in the secondary xylem, which is by contrast rich in lignified fibers and in wide vessels grouped in the metaxylem area; protoxylem parenchyma and adjacent pith are also lignified. In addition, in treated lower internodes, starch grains are less abundant than in controls, and this variation might be related to the decrease of photosynthesis. When taken together, qualitative and quantitative results indicate that the saline stress has a marked morpho-anatomical impact on the M. sativa Gabès stem. In particular, variations of secondary derivative distribution, increased wall thickening, lignification of phloem and xylem fibers and damage in the phloem complex are NaCl-induced responses, and are more expressed in the lower than in the upper internodes. The reinforcement of the stem lignified vasculature is thus a positive response to stress, but it has a negative impact on the quality of the forage. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bees (Hymenoptera, Apoidea, Apiformes in the Agricultural Landscape of Bulgaria: Species Diversity

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Banaszak Józef

2014-06-01

Full Text Available Wild bees (Apiformes were studied in 4 crop fields and 8 refuge habitats for 2 - 5 years in agricultural landscapes in the Pleven and Plovdiv regions of Bulgaria. In total, 233 bee species were recorded. Bee forage plants visited by the honey bee and wild Apiformes are listed for each refuge habitat. Species composition is given for individual habitats, including fields of alfalfa (Medicago sativa, oilseed rape (Brassica napus, sunflower (Helianthus annuus, and radish (Raphanus sativus. Species richness and dominance structure of bee communities in the 2 regions are compared, and species responsible for significant differences are identified.

Uromyces ciceris-arietini, the cause of chickpea rust: new hosts in the Trifolieae, Fabaceae

Science.gov (United States)

Plants of Medicago polymorpha in Riverside and San Diego, California were collected with severe rust caused by Uromyces ciceris-arietini. Reported hosts of U. ciceris-arietini are Cicer arietinum (chickpea) and Medicago polyceratia. To confirm the potential new host range, a monouredinial isolate RM...

The mycorrhiza-dependent defensin MtDefMd1 of Medicago truncatula acts during the late restructuring stages of arbuscule-containing cells.

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Marian Uhe

Full Text Available Different symbiotic and pathogenic plant-microbe interactions involve the production of cysteine-rich antimicrobial defensins. In Medicago truncatula, the expression of four MtDefMd genes, encoding arbuscular mycorrhiza-dependent defensins containing an N-terminal signal peptide and exhibiting some differences to non-symbiotic defensins, raised over the time of fungal colonization. Whereas the MtDefMd1 and MtDefMd2 promoters were inactive in cells containing young arbuscules, cells with fully developed arbuscules displayed different levels of promoter activities, indicating an up-regulation towards later stages of arbuscule formation. MtDefMd1 and MtDefMd2 expression was absent or strongly down-regulated in mycorrhized ram1-1 and pt4-2 mutants, known for defects in arbuscule branching or premature arbuscule degeneration, respectively. A ~97% knock-down of MtDefMd1/MtDefMd2 expression did not significantly affect arbuscule size. Although overexpression of MtDefMd1 in arbuscule-containing cells led to an up-regulation of MtRam1, encoding a key transcriptional regulator of arbuscule formation, no morphological changes were evident. Co-localization of an MtDefMd1-mGFP6 fusion with additional, subcellular markers revealed that this defensin is associated with arbuscules in later stages of their life-cycle. MtDefMd1-mGFP6 was detected in cells with older arbuscules about to collapse, and ultimately in vacuolar compartments. Comparisons with mycorrhized roots expressing a tonoplast marker indicated that MtDefMd1 acts during late restructuring processes of arbuscule-containing cells, upon their transition into a post-symbiotic state.

Dual inoculation with an Aarbuscular Mycorrhizal fungus and Rhizobium to facilitate the growth of alfalfa on coal mine substrates

Energy Technology Data Exchange (ETDEWEB)

Wu, F.Y.; Bi, Y.L.; Wong, M.H. [China University of Mining & Technology, Beijing (China)

2009-07-01

A pot experiment was conducted to investigate the effects of Glomus mosseae and Rhizobium on Medicago sativa grown on three types of coal mine substrates, namely a mixture of coal wastes and sands (CS), coal wastes and fly ash (CF), and fly ash (FA). Inoculation with Rhizobium alone did not result in any growth response but G. mosseae alone displayed a significant effect on plant growth. G. mosseae markedly increased the survival rate of M. sativa in CS substrate. In CF and FA substrates the respective oven dry weights of M. sativa inoculated with G. mosseae were 1.8 and 5.1 times higher than those without inoculation. Based on nitrogen (N), phosphorus (P) and potassium (K) uptake and legume growth, the results also show that dual inoculation in CS and CF substrates elicited a synergistic effect. This indicates that inoculation with arbuscular mycorrhizal (AM) fungi may be a promising approach for revegetation of coal mine substrates.

A Medicago truncatula Tobacco Retrotransposon Insertion Mutant Collection with Defects in Nodule Development and Symbiotic Nitrogen Fixation1[W][OA

Science.gov (United States)

Pislariu, Catalina I.; D. Murray, Jeremy; Wen, JiangQi; Cosson, Viviane; Muni, RajaSekhara Reddy Duvvuru; Wang, Mingyi; A. Benedito, Vagner; Andriankaja, Andry; Cheng, Xiaofei; Jerez, Ivone Torres; Mondy, Samuel; Zhang, Shulan; Taylor, Mark E.; Tadege, Million; Ratet, Pascal; Mysore, Kirankumar S.; Chen, Rujin; Udvardi, Michael K.

2012-01-01

A Tnt1-insertion mutant population of Medicago truncatula ecotype R108 was screened for defects in nodulation and symbiotic nitrogen fixation. Primary screening of 9,300 mutant lines yielded 317 lines with putative defects in nodule development and/or nitrogen fixation. Of these, 230 lines were rescreened, and 156 lines were confirmed with defective symbiotic nitrogen fixation. Mutants were sorted into six distinct phenotypic categories: 72 nonnodulating mutants (Nod−), 51 mutants with totally ineffective nodules (Nod+ Fix−), 17 mutants with partially ineffective nodules (Nod+ Fix+/−), 27 mutants defective in nodule emergence, elongation, and nitrogen fixation (Nod+/− Fix−), one mutant with delayed and reduced nodulation but effective in nitrogen fixation (dNod+/− Fix+), and 11 supernodulating mutants (Nod++Fix+/−). A total of 2,801 flanking sequence tags were generated from the 156 symbiotic mutant lines. Analysis of flanking sequence tags revealed 14 insertion alleles of the following known symbiotic genes: NODULE INCEPTION (NIN), DOESN’T MAKE INFECTIONS3 (DMI3/CCaMK), ERF REQUIRED FOR NODULATION, and SUPERNUMERARY NODULES (SUNN). In parallel, a polymerase chain reaction-based strategy was used to identify Tnt1 insertions in known symbiotic genes, which revealed 25 additional insertion alleles in the following genes: DMI1, DMI2, DMI3, NIN, NODULATION SIGNALING PATHWAY1 (NSP1), NSP2, SUNN, and SICKLE. Thirty-nine Nod− lines were also screened for arbuscular mycorrhizal symbiosis phenotypes, and 30 mutants exhibited defects in arbuscular mycorrhizal symbiosis. Morphological and developmental features of several new symbiotic mutants are reported. The collection of mutants described here is a source of novel alleles of known symbiotic genes and a resource for cloning novel symbiotic genes via Tnt1 tagging. PMID:22679222

Dicty_cDB: SFE866 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available cDNA library MtBC from arbuscular mycorrhiza of cultivar Jemalong of Medicago tru...protein. 94 1e-21 2 AL385573 |AL385573.1 Medicago truncatula EST MtBC29C12F1 : T3 end of clone MtBC29C12 of

Dicty_cDB: SSJ172 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available cDNA library MtBC from arbuscular mycorrhiza of cultivar Jemalong of Medicago tru...te cds. 494 e-147 3 AL386374 |AL386374.1 Medicago truncatula EST MtBC34C06F1 : T3 end of clone MtBC34C06 of

Genome-Wide Development of MicroRNA-Based SSR Markers in Medicago truncatula with Their Transferability Analysis and Utilization in Related Legume Species.

Science.gov (United States)

Min, Xueyang; Zhang, Zhengshe; Liu, Yisong; Wei, Xingyi; Liu, Zhipeng; Wang, Yanrong; Liu, Wenxian

2017-11-18

Microsatellite (simple sequence repeats, SSRs) marker is one of the most widely used markers in marker-assisted breeding. As one type of functional markers, MicroRNA-based SSR (miRNA-SSR) markers have been exploited mainly in animals, but the development and characterization of miRNA-SSR markers in plants are still limited. In the present study, miRNA-SSR markers for Medicago truncatula ( M. truncatula ) were developed and their cross-species transferability in six leguminous species was evaluated. A total of 169 primer pairs were successfully designed from 130 M. truncatula miRNA genes, the majority of which were mononucleotide repeats (70.41%), followed by dinucleotide repeats (14.20%), compound repeats (11.24%) and trinucleotide repeats (4.14%). Functional classification of SSR-containing miRNA genes showed that all targets could be grouped into three Gene Ontology (GO) categories: 17 in biological process, 11 in molecular function, and 14 in cellular component. The miRNA-SSR markers showed high transferability in other six leguminous species, ranged from 74.56% to 90.53%. Furthermore, 25 Mt - miRNA-SSR markers were used to evaluate polymorphisms in 20 alfalfa accessions, and the polymorphism information content (PIC) values ranged from 0.39 to 0.89 with an average of 0.71, the allele number per marker varied from 3 to 18 with an average of 7.88, indicating a high level of informativeness. The present study is the first time developed and characterized of M. truncatula miRNA-SSRs and demonstrated their utility in transferability, these novel markers will be valuable for genetic diversity analysis, marker-assisted selection and genotyping in leguminous species.

A regulatory network-based approach dissects late maturation processes related to the acquisition of desiccation tolerance and longevity of Medicago truncatula seeds.

Science.gov (United States)

Verdier, Jerome; Lalanne, David; Pelletier, Sandra; Torres-Jerez, Ivone; Righetti, Karima; Bandyopadhyay, Kaustav; Leprince, Olivier; Chatelain, Emilie; Vu, Benoit Ly; Gouzy, Jerome; Gamas, Pascal; Udvardi, Michael K; Buitink, Julia

2013-10-01

In seeds, desiccation tolerance (DT) and the ability to survive the dry state for prolonged periods of time (longevity) are two essential traits for seed quality that are consecutively acquired during maturation. Using transcriptomic and metabolomic profiling together with a conditional-dependent network of global transcription interactions, we dissected the maturation events from the end of seed filling to final maturation drying during the last 3 weeks of seed development in Medicago truncatula. The network revealed distinct coexpression modules related to the acquisition of DT, longevity, and pod abscission. The acquisition of DT and dormancy module was associated with abiotic stress response genes, including late embryogenesis abundant (LEA) genes. The longevity module was enriched in genes involved in RNA processing and translation. Concomitantly, LEA polypeptides accumulated, displaying an 18-d delayed accumulation compared with transcripts. During maturation, gulose and stachyose levels increased and correlated with longevity. A seed-specific network identified known and putative transcriptional regulators of DT, including ABSCISIC ACID-INSENSITIVE3 (MtABI3), MtABI4, MtABI5, and APETALA2/ ETHYLENE RESPONSE ELEMENT BINDING PROTEIN (AtAP2/EREBP) transcription factor as major hubs. These transcriptional activators were highly connected to LEA genes. Longevity genes were highly connected to two MtAP2/EREBP and two basic leucine zipper transcription factors. A heat shock factor was found at the transition of DT and longevity modules, connecting to both gene sets. Gain- and loss-of-function approaches of MtABI3 confirmed 80% of its predicted targets, thereby experimentally validating the network. This study captures the coordinated regulation of seed maturation and identifies distinct regulatory networks underlying the preparation for the dry and quiescent states.

Identification and Expression Analysis of Medicago truncatula Isopentenyl Transferase Genes (IPTs Involved in Local and Systemic Control of Nodulation

Directory of Open Access Journals (Sweden)

Mahboobeh Azarakhsh

2018-03-01

Full Text Available Cytokinins are essential for legume plants to establish a nitrogen-fixing symbiosis with rhizobia. Recently, the expression level of cytokinin biosynthesis IPTs (ISOPENTENYLTRANSFERASES genes was shown to be increased in response to rhizobial inoculation in Lotus japonicus, Medicago truncatula and Pisum sativum. In addition to its well-established positive role in nodule primordium initiation in root cortex, cytokinin negatively regulates infection processes in the epidermis. Moreover, it was reported that shoot-derived cytokinin inhibits the subsequent nodule formation through AON (autoregulation of nodulation pathway. In L. japonicus, LjIPT3 gene was shown to be activated in the shoot phloem via the components of AON system, negatively affecting nodulation. However, in M. truncatula, the detailed analysis of MtIPTs expression, both in roots and shoots, in response to nodulation has not been performed yet, and the link between IPTs and AON has not been studied so far. In this study, we performed an extensive analysis of MtIPTs expression levels in different organs, focusing on the possible role of MtIPTs in nodule development. MtIPTs expression dynamics in inoculated roots suggest that besides its early established role in the nodule primordia development, cytokinin may be also important for later stages of nodulation. According to expression analysis, MtIPT3, MtIPT4, and MtIPT5 are activated in the shoots in response to inoculation. Among these genes, MtIPT3 is the only one the induction of which was not observed in leaves of the sunn-3 mutant defective in CLV1-like kinase, the key component of AON, suggesting that MtIPT3 is activated in the shoots in an AON-dependent manner. Taken together, our findings suggest that MtIPTs are involved in the nodule development at different stages, both locally in inoculated roots and systemically in shoots, where their expression can be activated in an AON-dependent manner.

A Medicago truncatula EF-hand family gene, MtCaMP1, is involved in drought and salt stress tolerance.

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Tian-Zuo Wang

Full Text Available BACKGROUND: Calcium-binding proteins that contain EF-hand motifs have been reported to play important roles in transduction of signals associated with biotic and abiotic stresses. To functionally characterize genes of EF-hand family in response to abiotic stress, an MtCaMP1 gene belonging to EF-hand family from legume model plant Medicago truncatula was isolated and its function in response to drought and salt stress was investigated by expressing MtCaMP1 in Arabidopsis. METHODOLOGY/PRINCIPAL FINDINGS: Transgenic Arabidopsis seedlings expressing MtCaMP1 exhibited higher survival rate than wild-type seedlings under drought and salt stress, suggesting that expression of MtCaMP1 confers tolerance of Arabidopsis to drought and salt stress. The transgenic plants accumulated greater amounts of Pro due to up-regulation of P5CS1 and down-regulation of ProDH than wild-type plants under drought stress. There was a less accumulation of Na(+ in the transgenic plants than in WT plants due to reduced up-regulation of AtHKT1 and enhanced regulation of AtNHX1 in the transgenic plants compared to WT plants under salt stress. There was a reduced accumulation of H2O2 and malondialdehyde in the transgenic plants than in WT plants under both drought and salt stress. CONCLUSIONS/SIGNIFICANCE: The expression of MtCaMP1 in Arabidopsis enhanced tolerance of the transgenic plants to drought and salt stress by effective osmo-regulation due to greater accumulation of Pro and by minimizing toxic Na(+ accumulation, respectively. The enhanced accumulation of Pro and reduced accumulation of Na(+ under drought and salt stress would protect plants from water default and Na(+ toxicity, and alleviate the associated oxidative stress. These findings demonstrate that MtCaMP1 encodes a stress-responsive EF-hand protein that plays a regulatory role in response of plants to drought and salt stress.

Dicty_cDB: VHI867 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available scular mycorrhiza of cultivar Jemalong of Medicago truncatula (barrel medic). 46 0....uence. 44 0.006 2 AL387523 |AL387523.1 Medicago truncatula EST MtBC43B08F1 : T3 end of clone MtBC43B08 of cDNA library MtBC from arbu

Allelopathic Effect of Dodder on Different Varieties of Lucerne and Bird’s Foot-Trefoil

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Valcheva Ekaterina

2018-03-01

Full Text Available The aim of this study was to evaluate the allelopathic effect of cold aqueous extracts, both fresh and dry biomass of dodder (Cuscuta epithymum L. on lucerne (Medicago sativa L. and bird’s foot-trefoil (Lotus corniculatus L.. Four different varieties of lucerne “Pleven 6”, “Dara”, “Roly”, “Multifoliolate” and bird’s foot-trefoil (“Gran San Gabriele”, “Leo”, “Local population 1”, “Local population 2” were studied in order to find some varieties with allelopathic tolerance. Ex-situ experiment was carried out as follows: 100 seeds of each variety were put in Petri dishes between filter paper, both cold extracts of parasitic weed biomass were pipetted at a ratio of 1:20 as against the seed mass and then were placed in a thermostat-operated device at a temperature of 22 ± 2°С. Distilled water was used as a control. Percentage inhibition, Index of tolerance and Index of plant development were calculated for assessment of the allelopathic effect of dodder on the early seedling growth, biomass synthesis and initial development of experimental varieties. As a whole, dry weed biomass was found as more toxic for the tested plants than the fresh one. Medicago sativa var. multifoliolate and Lotus corniculatus var. Local population 1 and Local population 2 showed a significant tolerance to the allelopathic influence of Cuscuta epithymum in all studied concentrations of aqueous extract of fresh weed biomass (25, 50 and 100 g l−1 and medium tolerance to aqueous extract of dry weed biomass (concentrations of 25 and 50 g l−1.

Comparación de dos índices cuantitativos de estimación del estado de desarrollo de la alfalfa Comparison of two quantitative indexes for the estimation of alfalfa development stages

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M.L. Bernáldez

2006-12-01

Full Text Available El estado de desarrollo de la alfalfa (Medicago sativa L. es una variable de estudio común en evaluaciones de cultivares, dada su relación con la composición química y la tasa de crecimiento de la pastura. La determinación de los índices cuantitativos "estado medio por conteo" y "estado medio por peso" (EMC y EMP respectivamente permite la descripción del estado de desarrollo en pasturas de alfalfa de una manera objetiva y reproducible. Los índices EMC y EMP describen igualmente el estado de desarrollo de la alfalfa cuando la pastura se encuentra próxima al momento de utilización recomendado en la práctica. La ventaja de estimar EMC en relación a EMP, se basa en la rapidez operativa que ofrece la generación de datos para el cálculo del primero.The developmental stage of alfalfa (Medicago sativa L. is an usual variable of study when evaluating cultivars because of its relationship with chemical composition and pasture growth rate. Determination of quantitative indexes such as "mean stage by count" and "mean stage by weight" (MSC and MSW respectively makes it possible to describe the developmental phenological stages of alfalfa pastures in a more objective and reproducible way. Likewise, both the MSC and MSW indexes, describe the developmental stages of alfalfa when the pasture is close to the recommended utilisation time in practice. The advantage of estimating MSC in relation to MSW is based on the higher operative efficiency offered by the former in data generation for its calculation.

Alleviation of cadmium toxicity in Medicago sativa by hydrogen-rich water

Energy Technology Data Exchange (ETDEWEB)

Cui, Weiti; Gao, Cunyi; Fang, Peng [College of Life Sciences, Nanjing Agricultural University, Nanjing 210095 (China); Lin, Guoqing [Laboratory Center of Life Sciences, Co. Laboratory of Nanjing Agricultural University and Carl Zeiss Far East, Nanjing Agricultural University, Nanjing 210095 (China); Shen, Wenbiao, E-mail: wbshenh@njau.edu.cn [College of Life Sciences, Nanjing Agricultural University, Nanjing 210095 (China)

2013-09-15

Highlights: • HRW can alleviate Cd-induced alfalfa seedling growth inhibition and DNA laddering. • HRW alleviates Cd-induced oxidative stress by activating antioxidant enzymes. • Cd uptake in alfalfa seedling roots was decreased by HRW. • HRW can re-establish glutathione homeostasis under Cd stress. -- Abstract: Hydrogen gas (H{sub 2}) induces plant tolerance to several abiotic stresses, including salinity and paraquat exposure. However, the role of H{sub 2} in cadmium (Cd)-induced stress amelioration is largely unknown. Here, pretreatment with hydrogen-rich water (HRW) was used to characterize physiological roles and molecular mechanisms of H{sub 2} in the alleviation of Cd toxicity in alfalfa plants. Our results showed that the addition of HRW at 10% saturation significantly decreased contents of thiobarbituric acid reactive substances (TBARS) caused by Cd, and inhibited the appearance of Cd toxicity symptoms, including the improvement of root elongation and seedling growth. These responses were related to a significant increase in the total or isozymatic activities of representative antioxidant enzymes, or their corresponding transcripts. In vivo imaging of reactive oxygen species (ROS), and the detection of lipid peroxidation and the loss of plasma membrane integrity provided further evidence for the ability of HRW to improve Cd tolerance significantly, which was consistent with a significant enhancement of the ratio of reduced/oxidized (homo)glutathione ((h)GSH). Additionally, plants pretreated with HRW accumulated less amounts of Cd. Together, this study suggested that the usage of HRW could be an effective approach for Cd detoxification and could be explored in agricultural production systems.

Alleviation of cadmium toxicity in Medicago sativa by hydrogen-rich water

International Nuclear Information System (INIS)

Cui, Weiti; Gao, Cunyi; Fang, Peng; Lin, Guoqing; Shen, Wenbiao

2013-01-01

Highlights: • HRW can alleviate Cd-induced alfalfa seedling growth inhibition and DNA laddering. • HRW alleviates Cd-induced oxidative stress by activating antioxidant enzymes. • Cd uptake in alfalfa seedling roots was decreased by HRW. • HRW can re-establish glutathione homeostasis under Cd stress. -- Abstract: Hydrogen gas (H 2 ) induces plant tolerance to several abiotic stresses, including salinity and paraquat exposure. However, the role of H 2 in cadmium (Cd)-induced stress amelioration is largely unknown. Here, pretreatment with hydrogen-rich water (HRW) was used to characterize physiological roles and molecular mechanisms of H 2 in the alleviation of Cd toxicity in alfalfa plants. Our results showed that the addition of HRW at 10% saturation significantly decreased contents of thiobarbituric acid reactive substances (TBARS) caused by Cd, and inhibited the appearance of Cd toxicity symptoms, including the improvement of root elongation and seedling growth. These responses were related to a significant increase in the total or isozymatic activities of representative antioxidant enzymes, or their corresponding transcripts. In vivo imaging of reactive oxygen species (ROS), and the detection of lipid peroxidation and the loss of plasma membrane integrity provided further evidence for the ability of HRW to improve Cd tolerance significantly, which was consistent with a significant enhancement of the ratio of reduced/oxidized (homo)glutathione ((h)GSH). Additionally, plants pretreated with HRW accumulated less amounts of Cd. Together, this study suggested that the usage of HRW could be an effective approach for Cd detoxification and could be explored in agricultural production systems

MtNF-YA1, a central transcriptional regulator of symbiotic nodule development, is also a determinant of Medicago truncatula susceptibility towards a root pathogen.

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Thomas Rey

2016-12-01

Full Text Available Plant NF-Y transcription factors control a wide array of biological functions enabling appropriate reproductive and developmental processes as well as adaptation to various abiotic and biotic environments. In Medicago truncatula, MtNF-YA1 was previously identified as a key determinant for nodule development and establishment of rhizobial symbiosis. Here we highlight a new role for this protein in compatibility to Aphanomyces euteiches, a root pathogenic oomycete. The Mtnf-ya1-1 mutant plants showed better survival rate, reduced symptoms, and increased development of their root apparatus as compared to their wild type background A17. MtNF-YA-1 was specifically up-regulated by A. euteiches in F83005.5, a highly susceptible natural accession of M. truncatula while transcript level remained stable in A17, which is partially resistant. The role of MtNF-YA1 in F83005.5 susceptibility was further documented by reducing MtNF-YA1 expression either by overexpression of the miR169q, a microRNA targeting MtNF-YA1, or by RNAi approaches leading to a strong enhancement in the resistance of this susceptible line. Comparative analysis of the transcriptome of wild type and Mtnf-ya1-1 led to the identification of 1509 differentially expressed genes. Among those, almost 36 defence-related genes were constitutively expressed in Mtnf-ya1-1, while 20 genes linked to hormonal pathways were repressed. In summary, we revealed an unexpected dual role for this symbiotic transcription factor as a key player in the compatibility mechanisms to a pathogen.

Microstructure and ultrastructure of alfalfa seeds with different moisture contents after satellite carrying

International Nuclear Information System (INIS)

Feng Peng; Li Jian; Zhang Yunwei; Liu Ruohan

2009-01-01

Seeds with different moisture contents (9%, 11%, 13%, 15%, 17%) of Medicago sativa L. cv. Zhongmu No. 1 were boarded on the Shijian-8 satellite and then the microscopic and ultrastructure were observed. The results showed that spongy tissue and leaf palisade of plant after space flight were different to their control. The impact of on spongy cells was more obvious than the palisade cells; greater chloroplasts, empty and crack overflow mitochondria were observed. More starch grain were found at the samples cultured from 15% and 17% moisture content treatment, which was analyzed that starch grains in leaf cell was affected by the moisture content of seeds. (authors)

GeneBins: a database for classifying gene expression data, with application to plant genome arrays

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Weiller Georg

2007-03-01

Full Text Available Abstract Background To interpret microarray experiments, several ontological analysis tools have been developed. However, current tools are limited to specific organisms. Results We developed a bioinformatics system to assign the probe set sequences of any organism to a hierarchical functional classification modelled on KEGG ontology. The GeneBins database currently supports the functional classification of expression data from four Affymetrix arrays; Arabidopsis thaliana, Oryza sativa, Glycine max and Medicago truncatula. An online analysis tool to identify relevant functions is also provided. Conclusion GeneBins provides resources to interpret gene expression results from microarray experiments. It is available at http://bioinfoserver.rsbs.anu.edu.au/utils/GeneBins/

Alfalfa variety selection for maximum fiber content, protein and nitrogen fixation

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Ruhland, Christopher T. [Minnesota State Univ., Mankato, MN (United States); Knox, John [Minnesota State Univ., Mankato, MN (United States); Ward, Susan [Minnesota State Univ., Mankato, MN (United States); Agarwal, V. J. [Minnesota State Univ., Mankato, MN (United States); Frey, John [Minnesota State Univ., Mankato, MN (United States); Carrow, Duane [Minnesota State Univ., Mankato, MN (United States); Jones, Bruce [Minnesota State Univ., Mankato, MN (United States); Rife, James [Minnesota State Univ., Mankato, MN (United States)

2012-09-01

The fertile soils of Southern Minnesota are highly productive from both a natural and agricultural standpoint. We chose to examine potential feedstock in both of these settings as a focus for our study. In part one of this report we detail our findings examining potential feedstock in prairie and wetlands in the Mankato, MN area in 2009. We were able to familiarize ourselves with techniques used to isolate and quantify concentrations of cellulose, hemicellulose and lignin in both a classroom and laboratory setting. These techniques were then used for our experiments that examined the effects of harvest regime, irrigation and salinity on eight potential-feedstock varieties of alfalfa (Medicago sativa).

Dicty_cDB: Contig-U11911-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available 15738 ) EST1224699 MTY Medicago truncatula cDNA clone MTY... 46 0.077 2 ( BF643524 ) NF021F09EC1F1079 Elicited cell culture Medic...6 0.079 2 ( BF647644 ) NF078B01EC1F1011 Elicited cell culture Medicago t... 46 0....ited cell culture Medicago t... 46 0.086 2 ( BQ136068 ) NF032G12EC1F1099 Elicited cell culture Medic...tyostelium discoideum cDNA clone:ddc53b21, 3' ... 188 2e-47 2 ( CK249786 ) EST733423 potato callus cDNA library..., normalized ... 46 4e-04 3 ( CK249616 ) EST733253 potato callus cDNA library

The membrane proteome of Medicago truncatula roots displays qualitative and quantitative changes in response to arbuscular mycorrhizal symbiosis.

Science.gov (United States)

Abdallah, Cosette; Valot, Benoit; Guillier, Christelle; Mounier, Arnaud; Balliau, Thierry; Zivy, Michel; van Tuinen, Diederik; Renaut, Jenny; Wipf, Daniel; Dumas-Gaudot, Eliane; Recorbet, Ghislaine

2014-08-28

Arbuscular mycorrhizal (AM) symbiosis that associates roots of most land plants with soil-borne fungi (Glomeromycota), is characterized by reciprocal nutritional benefits. Fungal colonization of plant roots induces massive changes in cortical cells where the fungus differentiates an arbuscule, which drives proliferation of the plasma membrane. Despite the recognized importance of membrane proteins in sustaining AM symbiosis, the root microsomal proteome elicited upon mycorrhiza still remains to be explored. In this study, we first examined the qualitative composition of the root membrane proteome of Medicago truncatula after microsome enrichment and subsequent in depth analysis by GeLC-MS/MS. The results obtained highlighted the identification of 1226 root membrane protein candidates whose cellular and functional classifications predispose plastids and protein synthesis as prevalent organelle and function, respectively. Changes at the protein abundance level between the membrane proteomes of mycorrhizal and nonmycorrhizal roots were further monitored by spectral counting, which retrieved a total of 96 proteins that displayed a differential accumulation upon AM symbiosis. Besides the canonical markers of the periarbuscular membrane, new candidates supporting the importance of membrane trafficking events during mycorrhiza establishment/functioning were identified, including flotillin-like proteins. The data have been deposited to the ProteomeXchange with identifier PXD000875. During arbuscular mycorrhizal symbiosis, one of the most widespread mutualistic associations in nature, the endomembrane system of plant roots is believed to undergo qualitative and quantitative changes in order to sustain both the accommodation process of the AM fungus within cortical cells and the exchange of nutrients between symbionts. Large-scale GeLC-MS/MS proteomic analysis of the membrane fractions from mycorrhizal and nonmycorrhizal roots of M. truncatula coupled to spectral counting

Mutually Exclusive Alterations in Secondary Metabolism Are Critical for the Uptake of Insoluble Iron Compounds by Arabidopsis and Medicago truncatula1[C][W

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Rodríguez-Celma, Jorge; Lin, Wen-Dar; Fu, Guin-Mau; Abadía, Javier; López-Millán, Ana-Flor; Schmidt, Wolfgang

2013-01-01

The generally low bioavailability of iron in aerobic soil systems forced plants to evolve sophisticated genetic strategies to improve the acquisition of iron from sparingly soluble and immobile iron pools. To distinguish between conserved and species-dependent components of such strategies, we analyzed iron deficiency-induced changes in the transcriptome of two model species, Arabidopsis (Arabidopsis thaliana) and Medicago truncatula. Transcriptional profiling by RNA sequencing revealed a massive up-regulation of genes coding for enzymes involved in riboflavin biosynthesis in M. truncatula and phenylpropanoid synthesis in Arabidopsis upon iron deficiency. Coexpression and promoter analysis indicated that the synthesis of flavins and phenylpropanoids is tightly linked to and putatively coregulated with other genes encoding proteins involved in iron uptake. We further provide evidence that the production and secretion of phenolic compounds is critical for the uptake of iron from sources with low bioavailability but dispensable under conditions where iron is readily available. In Arabidopsis, homozygous mutations in the Fe(II)- and 2-oxoglutarate-dependent dioxygenase family gene F6′H1 and defects in the expression of PLEIOTROPIC DRUG RESISTANCE9, encoding a putative efflux transporter for products from the phenylpropanoid pathway, compromised iron uptake from an iron source of low bioavailability. Both mutants were partially rescued when grown alongside wild-type Arabidopsis or M. truncatula seedlings, presumably by secreted phenolics and flavins. We concluded that production and secretion of compounds that facilitate the uptake of iron is an essential but poorly understood aspect of the reduction-based iron acquisition strategy, which is likely to contribute substantially to the efficiency of iron uptake in natural conditions. PMID:23735511

Genome-Wide Transcriptional Changes and Lipid Profile Modifications Induced by Medicago truncatula N5 Overexpression at an Early Stage of the Symbiotic Interaction with Sinorhizobium meliloti

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Chiara Santi

2017-12-01

Full Text Available Plant lipid-transfer proteins (LTPs are small basic secreted proteins, which are characterized by lipid-binding capacity and are putatively involved in lipid trafficking. LTPs play a role in several biological processes, including the root nodule symbiosis. In this regard, the Medicago truncatula nodulin 5 (MtN5 LTP has been proved to positively regulate the nodulation capacity, controlling rhizobial infection and nodule primordia invasion. To better define the lipid transfer protein MtN5 function during the symbiosis, we produced MtN5-downregulated and -overexpressing plants, and we analysed the transcriptomic changes occurring in the roots at an early stage of Sinorhizobium meliloti infection. We also carried out the lipid profile analysis of wild type (WT and MtN5-overexpressing roots after rhizobia infection. The downregulation of MtN5 increased the root hair curling, an early event of rhizobia infection, and concomitantly induced changes in the expression of defence-related genes. On the other hand, MtN5 overexpression favoured the invasion of the nodules by rhizobia and determined in the roots the modulation of genes that are involved in lipid transport and metabolism as well as an increased content of lipids, especially galactolipids that characterize the symbiosome membranes. Our findings suggest the potential participation of LTPs in the synthesis and rearrangement of membranes occurring during the formation of the infection threads and the symbiosome membrane.

Potencial de espécies vegetais para a remediação do herbicida trifloxysulfuron-sodium Potential of plant species for remediation of trifloxysulfuron-sodium

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S.O. Procópio

2005-03-01

Full Text Available Este trabalho teve como objetivo avaliar a eficiência de espécies vegetais na remediação do herbicida trifloxysulfuron-sodium em solos, utilizando o feijão (Phaseolus vulgaris como planta indicadora. Os tratamentos foram compostos pela combinação entre as espécies Calopogonium mucunoides, Crotalaria juncea, Crotalaria spectabilis, Vicia sativa, Cajanus cajan, Canavalia ensiformis, Medicago sativa, Dolichus lab lab, Penisetum glaucum, Stylosantes guianensis, Mucuna deeringiana, Mucuna cinereum, Mucuna aterrima, Raphanus sativus e Lupinus albus. Todas as espécies foram semeadas em vasos no dia seguinte à aplicação do trifloxysulfuron-sodium em três doses (0,00; 3,75; e 15,00 g ha-1. Após 80 dias da semeadura, as espécies vegetais foram cortadas na altura do coleto e a parte aérea destas descartada. A seguir, foi realizada a semeadura do feijão (cultivar Pérola. Aos 45 dias após a emergência das plantas de feijão avaliaram-se a altura e a massa seca da parte aérea das plantas. Melhor eficiência na descontaminação do trifloxysulfuron-sodium em solo foi obtida pelas espécies M. aterrima e C. ensiformis.This work aimed to evaluate the efficiency of vegetable species in the remediation of the herbicide trifloxysulfuron-sodium in soils using the common bean (Phaseolus vulgaris as a bio indicator. The treatments were composed by the combination of the species Calopogonium mucunoides,Crotalaria juncea, Crotalaria spectabilis, Vicia sativa, Cajanus cajan, Canavalia ensiformis, Medicago sativa, Dolichus lab lab, Penisetum glaucum, Stylosantes guianensis, Mucuna deeringiana, Mucuna cinereum, Mucuna aterrima, Raphanus sativus and Lupinus albus, sown in vases the day following application of the herbicide at three doses (0.00; 3.75; and 15.00 g ha-1. Eighty days after sowing, the plants were cut and the shoot discarded, followed by bean ("Perola" cultivar sowing. At 45 days post emergence, bean height and shoot dry matter were

IDENTIFICATION AND OCCURRENCE OF FUSARIUM SPECIES ON SEEDS OF COMMON WETCH, WHITE LUPINE AND SOME WILD LEGUMES

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Tihomir Miličević

2013-06-01

Full Text Available The presence and occurrence of Fusarium species was examined on the seeds of cultivated legumes – common vetch (Vicia sativa, white lupine (Lupinus albus, and wild legumes: bird’s-foot trefoil (Lotus corniculatus, wild alfalfa (Medicago sativa, black locust (Robinia pseudoacacia, honey locust (Gleditsia triacanthos, sweet clover (Melilotus officinalis, bird vetch (Vicia cracca and meadow vetchling (Lathyrus pratensis. Thirteen Fusarium species were identified - F. verticillioides, F. acuminatum, F. avenaceum, F. tricinctum F. oxysporum, F. scirpi, F. semitectum, F. culmorum, F. proliferatum, F. pseudograminearum, F. sporotrichioides, F. sambucinum and F. heterosporum. Species F. verticillioides and F. proliferatum were determined on seeds of the cultivated legumes (common vetch and white lupine. Other 11 Fusarium species were determined on seeds of wild legumes (bird’s-foot trefoil, wild alfalfa, sweet clover and bird vetch among which the most prevalent were species F. avenaceum and F. acuminatum.

Both free indole-3-acetic acid and the photosynthetic performance are important players in the response of Medicago truncatula to urea and ammonium nutrition under axenic conditions

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RAQUEL eEsteban

2016-02-01

Full Text Available We aimed to identify the early stress response and plant performance of Medicago truncatula growing in axenic medium with ammonium or urea as the sole source of nitrogen with respect to nitrate based nutrition through biomass measurements, auxin contents analyses, root system architecture response analyses, and physiological determinations. Both ammonium and ureic nutrition severely affected the root system architecture, resulting in changes in the main elongation rate, lateral root development and insert position from the base. The auxin content decreased in both urea- and ammonium- treated roots; however, only the ammonium- treated plants were affected at the shoot level. The analysis of chlorophyll a fluorescence transients showed that ammonium affected photosystem II, but urea did not impair photosynthetic activity. Superoxide dismutase isoenzymes in the plastids were moderately affected by urea and ammonium in the roots. Overall, our results showed that low N doses from different sources had no remarkable effects on M. truncatula, with the exception of the differential phenotypic root response. High dose of both ammonium and urea caused great changes at plant length, auxin content and physiological determinations. The interesting correlations found between the shoot auxin pool, the plant length, and the parameter performance index, obtained from the chlorophyll a fluorescence rise kinetics measurements, indicated that both IAA pool and performance index are an important part of the response of M. truncatula under ammonium or urea as a sole N source.

Energizing marginal soils: A perennial cropping system for Sida hermaphrodita

Science.gov (United States)

Nabel, Moritz; Poorter, Hendrik; Temperton, Vicky; Schrey, Silvia D.; Koller, Robert; Schurr, Ulrich; Jablonowski, Nicolai D.

2017-04-01

As a way to avoid land use conflicts, the use of marginal soils for the production of plant biomass can be a sustainable alternative to conventional biomass production (e.g. maize). However, new cropping strategies have to be found that meet the challenge of crop production under marginal soil conditions. We aim for increased soil fertility by the use of the perennial crop Sida hermaphrodita in combination with organic fertilization and legume intercropping to produce substantial biomass yield. We present results of a three-year outdoor mesocosm experiment testing the perennial energy crop Sida hermaphrodita grown on a marginal model substrate (sand) with four kinds of fertilization (Digestate broadcast, Digestate Depot, mineral NPK and unfertilized control) in combination with legume intercropping. After three years, organic fertilization (via biogas digestate) compared to mineral fertilization (NPK), reduced the nitrate concentration in leachate and increased the soil carbon content. Biomass yields of Sida were 25% higher when fertilized organically, compared to mineral fertilizer. In general, digestate broadcast application reduced root growth and the wettability of the sandy substrate. However, when digestate was applied locally as depot to the rhizosphere, root growth increased and the wettability of the sandy substrate was preserved. Depot fertilization increased biomass yield by 10% compared to digestate broadcast fertilization. We intercropped Sida with various legumes (Trifolium repens, Trifolium pratense, Melilotus spp. and Medicago sativa) to enable biological nitrogen fixation and make the cropping system independent from synthetically produced fertilizers. We could show that Medicago sativa grown on marginal substrate fixed large amounts of N, especially when fertilized organically, whereas mineral fertilization suppressed biological nitrogen fixation. We conclude that the perennial energy crop Sida in combination with organic fertilization has great

Validation of Genotyping-By-Sequencing Analysis in Populations of Tetraploid Alfalfa by 454 Sequencing

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Rocher, Solen; Jean, Martine; Castonguay, Yves; Belzile, François

2015-01-01

Genotyping-by-sequencing (GBS) is a relatively low-cost high throughput genotyping technology based on next generation sequencing and is applicable to orphan species with no reference genome. A combination of genome complexity reduction and multiplexing with DNA barcoding provides a simple and affordable way to resolve allelic variation between plant samples or populations. GBS was performed on ApeKI libraries using DNA from 48 genotypes each of two heterogeneous populations of tetraploid alfalfa (Medicago sativa spp. sativa): the synthetic cultivar Apica (ATF0) and a derived population (ATF5) obtained after five cycles of recurrent selection for superior tolerance to freezing (TF). Nearly 400 million reads were obtained from two lanes of an Illumina HiSeq 2000 sequencer and analyzed with the Universal Network-Enabled Analysis Kit (UNEAK) pipeline designed for species with no reference genome. Following the application of whole dataset-level filters, 11,694 single nucleotide polymorphism (SNP) loci were obtained. About 60% had a significant match on the Medicago truncatula syntenic genome. The accuracy of allelic ratios and genotype calls based on GBS data was directly assessed using 454 sequencing on a subset of SNP loci scored in eight plant samples. Sequencing depth in this study was not sufficient for accurate tetraploid allelic dosage, but reliable genotype calls based on diploid allelic dosage were obtained when using additional quality filtering. Principal Component Analysis of SNP loci in plant samples revealed that a small proportion (<5%) of the genetic variability assessed by GBS is able to differentiate ATF0 and ATF5. Our results confirm that analysis of GBS data using UNEAK is a reliable approach for genome-wide discovery of SNP loci in outcrossed polyploids. PMID:26115486

Optimization of iTRAQ labelling coupled to OFFGEL fractionation as a proteomic workflow to the analysis of microsomal proteins of Medicago truncatula roots

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Abdallah Cosette

2012-06-01

Full Text Available Abstract Background Shotgun proteomics represents an attractive technical framework for the study of membrane proteins that are generally difficult to resolve using two-dimensional gel electrophoresis. The use of iTRAQ, a set of amine-specific isobaric tags, is currently the labelling method of choice allowing multiplexing of up to eight samples and the relative quantification of multiple peptides for each protein. Recently the hyphenation of different separation techniques with mass spectrometry was used in the analysis of iTRAQ labelled samples. OFFGEL electrophoresis has proved its effectiveness in isoelectric point-based peptide and protein separation in solution. Here we describe the first application of iTRAQ-OFFGEL-LC-MS/MS on microsomal proteins from plant material. The investigation of the iTRAQ labelling effect on peptide electrofocusing in OFFGEL fractionator was carried out on Medicago truncatula membrane protein digests. Results In-filter protein digestion, with easy recovery of a peptide fraction compatible with iTRAQ labelling, was successfully used in this study. The focusing quality in OFFGEL electrophoresis was maintained for iTRAQ labelled peptides with a higher than expected number of identified peptides in basic OFFGEL-fractions. We furthermore observed, by comparing the isoelectric point (pI fractionation of unlabelled versus labelled samples, a non-negligible pI shifts mainly to higher values. Conclusions The present work describes a feasible and novel protocol for in-solution protein digestion in which the filter unit permits protein retention and buffer removal. The data demonstrates an impact of iTRAQ labelling on peptide electrofocusing behaviour in OFFGEL fractionation compared to their native counterpart by the induction of a substantial, generally basic pI shift. Explanations for the occasionally observed acidic shifts are likewise presented.

Molecular docking of Glycine max and Medicago truncatula ureases with urea; bioinformatics approaches.

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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

Impact of Soil Salinity on the Structure of the Bacterial Endophytic Community Identified from the Roots of Caliph Medic (Medicago truncatula).

Science.gov (United States)

Yaish, Mahmoud W; Al-Lawati, Abbas; Jana, Gerry Aplang; Vishwas Patankar, Himanshu; Glick, Bernard R

2016-01-01

In addition to being a forage crop, Caliph medic (Medicago truncatula) is also a model legume plant and is used for research focusing on the molecular characterization of the interaction between rhizobia and plants. However, the endophytic microbiome in this plant is poorly defined. Endophytic bacteria play a role in supplying plants with the basic requirements necessary for growth and development. Moreover, these bacteria also play a role in the mechanism of salinity stress adaptation in plants. As a prelude to the isolation and utilization of these bacteria in Caliph medic farming, 41 bacterial OTUs were identified in this project from within the interior of the roots of this plant by pyrosequencing of the small ribosomal subunit gene (16S rDNA) using a cultivation-independent approach. In addition, the differential abundance of these bacteria was studied following exposure of the plants to salinity stress. About 29,064 high-quality reads were obtained from the sequencing of six libraries prepared from control and salinity-treated tissues. Statistical analysis revealed that the abundance of ~70% of the OTUs was significantly (p ≤ 0.05) altered in roots that were exposed to salinity stress. Sequence analysis showed a similarity between some of the identified species and other, known, growth-promoting bacteria, marine and salt-stressed soil-borne bacteria, and nitrogen-fixing bacterial isolates. Determination of the amendments to the bacterial community due to salinity stress in Caliph medic provides a crucial step toward developing an understanding of the association of these endophytes, under salt stress conditions, in this model plant. To provide direct evidence regarding their growth promoting activity, a group of endophytic bacteria were isolated from inside of plant roots using a cultivation-dependent approach. Several of these isolates were able to produce ACC-deaminase, ammonia and IAA; and to solubilize Zn+2 and PO4-3. This data is consistent with the

Effects of enhanced UVB on growth and yield of alfalfa and soybean under field conditions

International Nuclear Information System (INIS)

Al-Oudat, M.; Baydon, S.A.; Mohamad, A.

1998-01-01

The effects of 20% increase of UVB on growth and yield of alfalfa (Medicago Sativa L.) and two cultivars of soybean (Glycine Max (L.) Mer) under field conditions have been investigated. The increase of UVB dose ranged between 1.746 and 7.112 J/cm 2 during experiment. The results showed that soybean yield decrease by 16% and 31% in A. 3803 and A. 2522 cultivars respectively, under UVB exposure. The dry weight and leaf area were sensitive in the A. 3803 cultivar, while they were tolerant in the A. 2522 cultivar. Alfalfa response to UVB varied during the different stages of growth, whereas the yield was 12% less in the exposed plants. (author)

Antifungal (Gaeumannomyces graminis var. tritici activity of various glycosides of medicagenic acid

Directory of Open Access Journals (Sweden)

Stefan Martyniuk

2012-12-01

Full Text Available Different concentrations of medicagenic acid and five glycosides of this acid isolated from alfalfa (Medicago sativa were added to agar medium (corn meal agar, CMA inoculated with cultures of Gaeumannomyces graminis var. tritici (Ggt. After 7 days of incubation at 25oC colony radius was measured and % of inhibition calculated in relation to the control medium (CMA enriched with the solvent of the tested compounds. Within the tested concentrations, only 3-O-β -D -glucopiranoside medicagenate (monoglucoside significantly reduced the growth of Ggt on CMA medium. This compound at 0.05 mM concentration completely inhibited the development of the fungus and the effect was shown to be fungi-toxic.

Novel Occurrence of Uncommon Polyamines in Higher Plants 1

Science.gov (United States)

Kuehn, Glenn D.; Rodriguez-Garay, Benjamin; Bagga, Suman; Phillips, Gregory C.

1990-01-01

Diamines and polyamines are ubiquitous components of living cells, and apparently are involved in numerous cellular and physiological processes. Certain “uncommon” polyamines have limited distribution in nature and have been associated primarily with organisms adapted to extreme environments, although the precise function of these polyamines in such organisms is unknown. This article summarizes current knowledge regarding the occurrence in higher plants of the uncommon polyamines related to and including norspermidine and norspermine. A putative biosynthetic pathway to account for the occurrences of these uncommon polyamines in higher plants is presented, with a summary of the supporting evidence indicating the existence of the requisite enzymatic activities in alfalfa, Medicago sativa L. PMID:16667862

Germination and root elongation bioassays in six different plant species for testing Ni contamination in soil.

Science.gov (United States)

Visioli, Giovanna; Conti, Federica D; Gardi, Ciro; Menta, Cristina

2014-04-01

In vitro short-term chronic phytotoxicity germination and root elongation test were applied to test the effects of nickel (Ni) in seed germination and root elongation in six plants species: Cucumis sativus (Cucurbitaceae), Lepidium sativum and Brassica nigra (Brassicaceae), Trifolium alexandrinum and Medicago sativa (Fabaceae), Phacelia tanacetifolia (Boraginaceae). A naturally Ni rich soil was used to compare the results obtained. Unlike root elongation, germination was not affected by Ni in any of the six species tested. EC50 values, calculated on the root elongation, showed that Ni toxicity decreases in the following order: P. tanacetifolia > B. nigra > C. sativus > L. sativum > M. sativa > T. alexandrinum. The test conducted using soil elutriate revealed a significantly lower effect in both seed germination and root elongation when compared to the results obtained using untreated soil. Conversely, the test performed on soil confirmed the high sensitivity of C. sativus, P. tanacetifolia and L. sativum to Ni.

Effect of Non Thermal Plasma on Alfalfa (Medicago sativa L.) Forage Production

International Nuclear Information System (INIS)

Abd El-Daem, G.A.N.A.; El-Aragi, G.M.; Tarrad, M.M.; Zayed, E.M.

2013-01-01

Field experiments were conducted at Atomic Energy Authority (AEA) Farm, at Inshas, Egypt during 2011–2012 on alfalfa. The aim of this investigation to caused mutation in alfalfa to obtain new variation. Seeds of the alfalfa were subjected to six doses of non-thermal plasma pulse. The plasma (consisting of ozone, UV and visible light) was injected into the seed samples for different durations or number of pulses. The doses used treatments were 2, 4, 6, 8, and 10 pulses (P) and non-treated control. The results showed difference seeds in both level field performances from cut 1st to cut 10th in the forage production. The results showed differences between the Control and treatment (number of pulses (P)) in each of all cuts for the productivity. The results showed the impact of plant height, Number of leaves/plant and number of branches/leaf and stem diameter as well as fresh weight of plant, fresh/weight (t/fed), dry yield (t/fed) in some cuts for Pulses 2, 4 and 10, and the ten pulses were the best for the majority of the qualities and cuts.

Detoxification of Atrazine by Low Molecular Weight Thiols in Alfalfa (Medicago sativa).

Science.gov (United States)

Zhang, Jing Jing; Xu, Jiang Yan; Lu, Feng Fan; Jin, She Feng; Yang, Hong

2017-10-16

Low molecular weight (LMW) thiols in higher plants are a group of sulfur-rich nonprotein compounds and play primary and multiple roles in cellular redox homeostasis, enzyme activities, and xenobiotics detoxification. This study focused on identifying thiols-related protein genes from the legume alfalfa exposed to the herbicide atrazine (ATZ) residues in environment. Using high-throughput RNA-sequencing, a set of ATZ-responsive thiols-related protein genes highly up-regulated and differentially expressed in alfalfa was identified. Most of the differentially expressed genes (DEGs) were involved in regulation of biotic and abiotic stress responses. By analyzing the genes involved in thiols-mediated redox homeostasis, we found that many of them were thiols-synthetic enzymes such as γ-glutamylcysteine synthase (γECS), homoglutathione synthetase (hGSHS), and glutathione synthetase (GSHS). Using liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS), we further characterized a group of ATZ-thiols conjugates, which are the detoxified forms of ATZ in plants. Cysteine S-conjugate ATZ-HCl+Cys was the most important metabolite detected by MS. Several other ATZ-conjugates were also examined as ATZ-detoxified metabolites. Such results were validated by characterizing their analogs in rice. Our data showed that some conjugates under ATZ stress were detected in both plants, indicating that some detoxified mechanisms and pathways can be shared by the two plant species. Overall, these results indicate that LMW thiols play critical roles in detoxification of ATZ in the plants.

The effects of ascorbic acid on salt induced alfalfa (Medicago sativa L.)

African Journals Online (AJOL)

Dr. J. T. Ekanem

contribute to the high electrical conductivity of salt-affected lands3. ... the cellular mechanisms of the stress and its application at the .... Fig 2: Effect of salt and ascorbic acid on a) stem length, b) root length, c) root number, d) dry weight of ...

Cyclin-like F-box protein plays a role in growth and development of the three model species Medicago truncatula, Lotus japonicus, and Arabidopsis thaliana

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Boycheva I

2015-08-01

Full Text Available Irina Boycheva,1 Valya Vassileva,2 Miglena Revalska,1 Grigor Zehirov,2 Anelia Iantcheva1 1Department of Functional Genetics Legumes, 2AgroBioInstitute, Department of Plant Stress Molecular Biology, Institute of Plant Physiology and Genetics, Sofia, Bulgaria Abstract: In eukaryotes, F-box proteins are one of the main components of the SCF complex that belongs to the family of ubiquitin E3 ligases, which catalyze protein ubiquitination and maintain the balance between protein synthesis and degradation. In the present study, we clarified the role and function of the gene encoding cyclin-like F-box protein from Medicago truncatula using transgenic plants of the model species M. truncatula, Lotus japonicas, and Arabidopsis thaliana generated by Agrobacterium-mediated transformation. Morphological and transcriptional analyses combined with flow cytometry and histochemistry demonstrated the participation of this protein in many aspects of plant growth and development, including processes of indirect somatic embryogenesis and symbiotic nodulation. The cyclin-like F-box gene showed expression in all plant organs and tissues comprised of actively dividing cells. The observed variations in root and hypocotyl growth, leaf and silique development, ploidy levels, and leaf parameters in the obtained transgenic lines demonstrated the effects of this gene on organ development. Furthermore, knockdown of cyclin-like F-box led to accumulation of higher levels of the G2/M transition-specific gene cyclin B1:1 (CYCB1:1, suggesting its possible role in cell cycle control. Together, the collected data suggest a similar role of the cyclin-like F-box protein in the three model species, providing evidence for the functional conservation of the studied gene. Keywords: cyclin-like F-box, model legumes, Arabidopsis thaliana, plant growth, plant development, cell cycle

Overexpression of MfPIP2-7 from Medicago falcata promotes cold tolerance and growth under NO3 (-) deficiency in transgenic tobacco plants.

Science.gov (United States)

Zhuo, Chunliu; Wang, Ting; Guo, Zhenfei; Lu, Shaoyun

2016-06-14

Plasma membrane intrinsic proteins (PIPs), which belong to aquaporins (AQPs) superfamily, are subdivided into two groups, PIP1 and PIP2, based on sequence similarity. Several PIP2s function as water channels, while PIP1s have low or no water channel activity, but have a role in water permeability through interacting with PIP2. A cold responsive PIP2 named as MfPIP2-7 was isolated from Medicago falcata (hereafter falcata), a forage legume with great cold tolerance, and transgenic tobacco plants overexpressing MfPIP2-7 were analyzed in tolerance to multiple stresses including freezing, chilling, and nitrate reduction in this study. MfPIP2-7 transcript was induced by 4 to 12 h of cold treatment and 2 h of abscisic acid (ABA) treatment. Pretreatment with inhibitor of ABA synthesis blocked the cold induced MfPIP2-7 transcript, indicating that ABA was involved in cold induced transcription of MfPIP2-7 in falcata. Overexpression of MfPIP2-7 resulted in enhanced tolerance to freezing, chilling and NO3 (-) deficiency in transgenic tobacco (Nicotiana tabacum L.) plants as compared with the wild type. Moreover, MfPIP2-7 was demonstrated to facilitate H2O2 diffusion in yeast. Higher transcript levels of several stress responsive genes, such as NtERD10B, NtERD10C, NtDREB1, and 2, and nitrate reductase (NR) encoding genes (NtNIA1, and NtNIA2) were observed in transgenic plants as compared with the wild type with dependence upon H2O2. In addition, NR activity was increased in transgenic plants, which led to alterations in free amino acid components and concentrations. The results suggest that MfPIP2-7 plays an important role in plant tolerance to freezing, chilling, and NO3 (-) deficiency by promoted H2O2 diffusion that in turn up-regulates expression of NIAs and multiple stress responsive genes.

The Seed Repair Response during Germination: Disclosing Correlations between DNA Repair, Antioxidant Response, and Chromatin Remodeling in Medicago truncatula

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Andrea Pagano

2017-11-01

Full Text Available This work provides novel insights into the effects caused by the histone deacetylase inhibitor trichostatin A (TSA during Medicago truncatula seed germination, with emphasis on the seed repair response. Seeds treated with H2O and TSA (10 and 20 μM were collected during imbibition (8 h and at the radicle protrusion phase. Biometric data showed delayed germination and impaired seedling growth in TSA-treated samples. Comet assay, performed on radicles at the protrusion phase and 4-days old M. truncatula seedlings, revealed accumulation of DNA strand breaks upon exposure to TSA. Activation of DNA repair toward TSA-mediated genotoxic damage was evidenced by the up-regulation of MtOGG1(8-OXOGUANINE GLYCOSYLASE/LYASE gene involved in the removal of oxidative DNA lesions, MtLIGIV(LIGASE IV gene, a key determinant of seed quality, required for the rejoining of DNA double strand breaks and TDP(TYROSYL-DNA PHOSPHODIESTERASE genes encoding the multipurpose DNA repair enzymes tyrosyl-DNA phosphodiesterases. Since radical scavenging can prevent DNA damage, the specific antioxidant activity (SAA was measured by DPPH (1,1-diphenyl-2-picrylhydrazyl and Folin-Ciocalteu reagent assays. Fluctuations of SAA were observed in TSA-treated seeds/seedlings concomitant with the up-regulation of antioxidant genes MtSOD(SUPEROXIDE DISMUTASE, MtAPX(ASCORBATE PEROXIDASE and MtMT2(TYPE 2 METALLOTHIONEIN. Chromatin remodeling, required to facilitate the access of DNA repair enzymes at the damaged sites, is also part of the multifaceted seed repair response. To address this aspect, still poorly explored in plants, the MtTRRAP(TRANSFORMATION/TRANSACTIVATION DOMAIN-ASSOCIATED PROTEIN gene was analyzed. TRRAP is a transcriptional adaptor, so far characterized only in human cells where it is needed for the recruitment of histone acetyltransferase complexes to chromatin during DNA repair. The MtTRRAP gene and the predicted interacting partners MtHAM2 (HISTONE ACETYLTRANSFERASE OF

WRKY domain-encoding genes of a crop legume chickpea (Cicer arietinum): comparative analysis with Medicago truncatula WRKY family and characterization of group-III gene(s).

Science.gov (United States)

Kumar, Kamal; Srivastava, Vikas; Purayannur, Savithri; Kaladhar, V Chandra; Cheruvu, Purnima Jaiswal; Verma, Praveen Kumar

2016-06-01

The WRKY genes have been identified as important transcriptional modulators predominantly during the environmental stresses, but they also play critical role at various stages of plant life cycle. We report the identification of WRKY domain (WD)-encoding genes from galegoid clade legumes chickpea (Cicer arietinum L.) and barrel medic (Medicago truncatula). In total, 78 and 98 WD-encoding genes were found in chickpea and barrel medic, respectively. Comparative analysis suggests the presence of both conserved and unique WRKYs, and expansion of WRKY family in M. truncatula primarily by tandem duplication. Exclusively found in galegoid legumes, CaWRKY16 and its orthologues encode for a novel protein having a transmembrane and partial Exo70 domains flanking a group-III WD. Genomic region of galegoids, having CaWRKY16, is more dynamic when compared with millettioids. In onion cells, fused CaWRKY16-EYFP showed punctate fluorescent signals in cytoplasm. The chickpea WRKY group-III genes were further characterized for their transcript level modulation during pathogenic stress and treatments of abscisic acid, jasmonic acid, and salicylic acid (SA) by real-time PCR. Differential regulation of genes was observed during Ascochyta rabiei infection and SA treatment. Characterization of A. rabiei and SA inducible gene CaWRKY50 showed that it localizes to plant nucleus, binds to W-box, and have a C-terminal transactivation domain. Overexpression of CaWRKY50 in tobacco plants resulted in early flowering and senescence. The in-depth comparative account presented here for two legume WRKY genes will be of great utility in hastening functional characterization of crop legume WRKYs and will also help in characterization of Exo70Js. © The Author 2016. Published by Oxford University Press on behalf of Kazusa DNA Research Institute.

Structural Basis for Dual Functionality of Isoflavonoid O-Methyltransferases in the Evolution of Plant Defense Responses

Energy Technology Data Exchange (ETDEWEB)

Liu, C.; Deavours, B; Richard, S; Ferrer, J; Blount, J; Huhman, D; Dixon, R; Noel, J

2006-01-01

In leguminous plants such as pea (Pisum sativum), alfalfa (Medicago sativa), barrel medic (Medicago truncatula), and chickpea (Cicer arietinum), 4'-O-methylation of isoflavonoid natural products occurs early in the biosynthesis of defense chemicals known as phytoalexins. However, among these four species, only pea catalyzes 3-O-methylation that converts the pterocarpanoid isoflavonoid 6a-hydroxymaackiain to pisatin. In pea, pisatin is important for chemical resistance to the pathogenic fungus Nectria hematococca. While barrel medic does not biosynthesize 6a-hydroxymaackiain, when cell suspension cultures are fed 6a-hydroxymaackiain, they accumulate pisatin. In vitro, hydroxyisoflavanone 4'-O-methyltransferase (HI4'OMT) from barrel medic exhibits nearly identical steady state kinetic parameters for the 4'-O-methylation of the isoflavonoid intermediate 2,7,4'-trihydroxyisoflavanone and for the 3-O-methylation of the 6a-hydroxymaackiain isoflavonoid-derived pterocarpanoid intermediate found in pea. Protein x-ray crystal structures of HI4'OMT substrate complexes revealed identically bound conformations for the 2S,3R-stereoisomer of 2,7,4'-trihydroxyisoflavanone and the 6aR,11aR-stereoisomer of 6a-hydroxymaackiain. These results suggest how similar conformations intrinsic to seemingly distinct chemical substrates allowed leguminous plants to use homologous enzymes for two different biosynthetic reactions. The three-dimensional similarity of natural small molecules represents one explanation for how plants may rapidly recruit enzymes for new biosynthetic reactions in response to changing physiological and ecological pressures.

Structural Basis for Dual Functionality of Isoflavonoid O-Methyltransferases in the Evolution of Plant Defense Responses

Energy Technology Data Exchange (ETDEWEB)

Liu, C.-J.; Deavours, B.E.; Richard, S.B.; Ferrer, J.-L.; Blount, J.W.; Huhman, D.; Dixon, R.A.; Noel, J.

2007-07-10

In leguminous plants such as pea (Pisum sativum), alfalfa (Medicago sativa), barrel medic (Medicago truncatula), and chickpea (Cicer arietinum), 4'-O-methylation of isoflavonoid natural products occurs early in the biosynthesis of defense chemicals known as phytoalexins. However, among these four species, only pea catalyzes 3-O-methylation that converts the pterocarpanoid isoflavonoid 6a-hydroxymaackiain to pisatin. In pea, pisatin is important for chemical resistance to the pathogenic fungus Nectria hematococca. While barrel medic does not biosynthesize 6a-hydroxymaackiain, when cell suspension cultures are fed 6a-hydroxymaackiain, they accumulate pisatin. In vitro, hydroxyisoflavanone 4'-O-methyltransferase (HI4'OMT) from barrel medic exhibits nearly identical steady state kinetic parameters for the 4'-O-methylation of the isoflavonoid intermediate 2,7,4'-trihydroxyisoflavanone and for the 3-O-methylation of the 6a-hydroxymaackiain isoflavonoid-derived pterocarpanoid intermediate found in pea. Protein x-ray crystal structures of HI4'OMT substrate complexes revealed identically bound conformations for the 2S,3R-stereoisomer of 2,7,4'-trihydroxyisoflavanone and the 6aR,11aR-stereoisomer of 6a-hydroxymaackiain. These results suggest how similar conformations intrinsic to seemingly distinct chemical substrates allowed leguminous plants to use homologous enzymes for two different biosynthetic reactions. The three-dimensional similarity of natural small molecules represents one explanation for how plants may rapidly recruit enzymes for new biosynthetic reactions in response to changing physiological and ecological pressures.

Dicty_cDB: Contig-U12726-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available ( DU826786 ) FLAS_CR30-2002_05F11.T7M FLAS_CR30-2002 unculture... 46 0.41 1 ( AL404104 ) T3 end of clone AT0AA013B12 of library...mid clone: MOF-010N15, gen... 46 0.41 1 ( CT559968 ) A BAC library has been constructed from cultivar ... 46...1 ( BG450438 ) NF015E06DT1F1051 Drought Medicago truncatula cDNA... 50 0.027 1 ( BF649099 ) NF055E07EC1F1053 Elicited cell culture... Medicago t... 50 0.027 1 ( BF644378 ) NF061A10EC1F1072 Elicited cell culture Medicago...M0435G20F Mouse 10kb plasmid UUGC1M library Mus ... 48 0.10 1 ( AL405948 ) T7 end of clone AU0AA007C03 of library

Using RNA-Seq for gene identification, polymorphism detection and transcript profiling in two alfalfa genotypes with divergent cell wall composition in stems

Science.gov (United States)

2011-01-01

Background Alfalfa, [Medicago sativa (L.) sativa], a widely-grown perennial forage has potential for development as a cellulosic ethanol feedstock. However, the genomics of alfalfa, a non-model species, is still in its infancy. The recent advent of RNA-Seq, a massively parallel sequencing method for transcriptome analysis, provides an opportunity to expand the identification of alfalfa genes and polymorphisms, and conduct in-depth transcript profiling. Results Cell walls in stems of alfalfa genotype 708 have higher cellulose and lower lignin concentrations compared to cell walls in stems of genotype 773. Using the Illumina GA-II platform, a total of 198,861,304 expression sequence tags (ESTs, 76 bp in length) were generated from cDNA libraries derived from elongating stem (ES) and post-elongation stem (PES) internodes of 708 and 773. In addition, 341,984 ESTs were generated from ES and PES internodes of genotype 773 using the GS FLX Titanium platform. The first alfalfa (Medicago sativa) gene index (MSGI 1.0) was assembled using the Sanger ESTs available from GenBank, the GS FLX Titanium EST sequences, and the de novo assembled Illumina sequences. MSGI 1.0 contains 124,025 unique sequences including 22,729 tentative consensus sequences (TCs), 22,315 singletons and 78,981 pseudo-singletons. We identified a total of 1,294 simple sequence repeats (SSR) among the sequences in MSGI 1.0. In addition, a total of 10,826 single nucleotide polymorphisms (SNPs) were predicted between the two genotypes. Out of 55 SNPs randomly selected for experimental validation, 47 (85%) were polymorphic between the two genotypes. We also identified numerous allelic variations within each genotype. Digital gene expression analysis identified numerous candidate genes that may play a role in stem development as well as candidate genes that may contribute to the differences in cell wall composition in stems of the two genotypes. Conclusions Our results demonstrate that RNA-Seq can be

Biological activity of saponins from alfalfa tops and roots against Colorado potato beetle larvae

Directory of Open Access Journals (Sweden)

Maryla Szczepaniak

2013-12-01

Full Text Available The total saponins of alfalfa, Medicago sativa L., included in the diet of Colorado potato beetle larvae reduced their feeding, growth rate and survival. The biological activity of those compounds coming both from the roots and from the aerial parts is closely correlated with the dose. Larvae reared on leaves treated with a 0,5% dose virtually did not feed at all and died after 4-6 days. Lower saponin doses (0,01 and 0,001 % reduced the insects' feeding to a lesser degree. However, they inhibited their growth, caused an extension of the larval stage and mortality at a level of 76,7- 100%. No major differences have been found in saponin activity depending on its localization in the plant.

Yields of alfalfa varieties with different fall dormancy levels in northeast china

International Nuclear Information System (INIS)

Chen, J.S.; Zhu, R.F.; Di, G.L.

2014-01-01

Fall dormancy (FD) is an important indicator of winter hardiness in alfalfa (Medicago sativa L.), the relationship between FD and the yield potential of alfalfa varieties were investigated to survey annual dry matter (DM) yields with FD levels in the northeast regions with cold winters. During three consecutive years, all varieties of five FD levels survived over the winter without any persistency problems and there were no differences in annual DM yields of varieties among FD levels. Among the same FD varieties, DM yields for some of the dormant, semi-dormant and non-dormant varieties were found no correlated with FD levels. In conclusion, it suggests that different FD levels no effected on yields of alfalfa in the cold regions, such as North-east China. (author)

Impact of Soil Salinity on the Structure of the Bacterial Endophytic Community Identified from the Roots of Caliph Medic (Medicago truncatula.

Directory of Open Access Journals (Sweden)

Mahmoud W Yaish

Full Text Available In addition to being a forage crop, Caliph medic (Medicago truncatula is also a model legume plant and is used for research focusing on the molecular characterization of the interaction between rhizobia and plants. However, the endophytic microbiome in this plant is poorly defined. Endophytic bacteria play a role in supplying plants with the basic requirements necessary for growth and development. Moreover, these bacteria also play a role in the mechanism of salinity stress adaptation in plants. As a prelude to the isolation and utilization of these bacteria in Caliph medic farming, 41 bacterial OTUs were identified in this project from within the interior of the roots of this plant by pyrosequencing of the small ribosomal subunit gene (16S rDNA using a cultivation-independent approach. In addition, the differential abundance of these bacteria was studied following exposure of the plants to salinity stress. About 29,064 high-quality reads were obtained from the sequencing of six libraries prepared from control and salinity-treated tissues. Statistical analysis revealed that the abundance of ~70% of the OTUs was significantly (p ≤ 0.05 altered in roots that were exposed to salinity stress. Sequence analysis showed a similarity between some of the identified species and other, known, growth-promoting bacteria, marine and salt-stressed soil-borne bacteria, and nitrogen-fixing bacterial isolates. Determination of the amendments to the bacterial community due to salinity stress in Caliph medic provides a crucial step toward developing an understanding of the association of these endophytes, under salt stress conditions, in this model plant. To provide direct evidence regarding their growth promoting activity, a group of endophytic bacteria were isolated from inside of plant roots using a cultivation-dependent approach. Several of these isolates were able to produce ACC-deaminase, ammonia and IAA; and to solubilize Zn+2 and PO4-3. This data is

[Allelopathic effects of the humus soils from Betula platyphylla and Quercus liaotungensis pure plantations on 9 kinds of common shrubs and herbs].

Science.gov (United States)

Huang, Liang-Jia; Liu, Zeng-wen; Zhu, Bo-Chao; Bing, Yuan-Hao; Zhang, Xiao-Xi; Lü, Chen

2014-06-01

The humus soils were collected from Betula platyphylla and Quercus liaotungensis pure plantations and woodless land separately where the site conditions were basically the same, and taken as medium for potting culture test of 9 kinds of shrubs or herbs in plastic greenhouse to assess the allelopathic effects of humus soils of pure plantations on shrubs or herbs. Humus soils from B. platyphylla plantation significantly inhibited the seed germinations of Medicago sativa and Melilotus officinalis, decreased the catalase (CAT) activity of M. officinalis, Coronilla varia, M. sativa and Lespedeza davurica, and improved malondialdehyde (MDA) contents in seedlings of Caragana kor-shinskii, C. varia and Astragalus adsurgens. The biomass growths of C. varia, Amorpha fruticosa, M. sativa, M. officinalis and A. adsurgens in humus soils from B. platyphylla plantation were significantly decreased by 48.2%, 45.1%, 44.3%, 37.3% and 36.0%, respectively. In addition, humus soil of Q. liaotungensis plantation significantly decreased the germination rates of M. sativa and A. adsurgens, the chlorophyll contents of Vicia villosa, A. fruticosa and M. sativa, and improved malondialdehyde (MDA) contents in seedlings of Lespedeza davurica, Caragana korshinskii, M. officinalis and A. adsurgens. The biomass growths of A. adsurgens, M. sativa, M. officinalis and A. fruticosa were significantly decreased by 52.6% , 43.8%, 35.5% and 34.6%, respective- ly. B. platyphylla plantation humus soil had obvious inhibition effects on M. sativa, M. officinalis and A. fruticosa, while Q. liaotungensis plantation humus soil had obvious inhibition effects on M. sativa, A. adsurgens and A. fruticosa.

Germination success under different treatments and pod sowing depths in six legume species present in olive groves

Energy Technology Data Exchange (ETDEWEB)

Siles, S.; García-Zafra, A.; Torres, J.A.; García-Fuentes, A.; Ruiz-Valenzuela, L.

2017-07-01

This study analysed the germination success of pods of six annual native legumes species: Astragalus hamosus, Medicago minima, Medicago orbicularis, Medicago polymorpha, Medicago rigidula and Scorpiurus muricatus. The use of these species has been proposed as a means of generating and improving herbaceous cover in olive groves. Germination success was studied in terms of the variability in the number of seeds germinated per pod after 18 months at two different sowing depths, on the surface (S) and buried 10 mm (B). Pods were subject to five different pre-germination treatments: chemical scarification, consisting of immersion in sulphuric acid for 15 min (S{sub 1}5) and 20 min (S{sub 2}0), immersion in water for 48 h (W{sub 4}8), pod precooled to -18ºC for one month (P{sub 1}8º) and untreated pods (Con). The results showed that the effectiveness of the different treatments and sowing depths depended on the species, and that there were no problems of ‘sibling-competition’ in any of the treatments or at any of the sowing depths. Species with larger, non-spiralled pods, such as A. hamosus or S. muricatus, or with very loosely spiralled pods such as M. orbicularis, had greater germination rates when buried, mainly in the case of untreated pods and pods that were immersed in sulphuric acid for 20 minutes.

The effect of fire on the dormancy break of annual legume seeds

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Fabio Gresta

2011-07-01

Full Text Available Fire is a common phenomenon in the Mediterranean environment and strongly influences vegetal population dynamics through its impact on vegetation and the soil seed bank. Fire is able to break down the seed coat of hard-seeded legumes within the soil and trigger germination. To evaluate the effect of fire on the dormancy break in Medicago ciliaris, Medicago rugosa and Scorpiurus muricatus subsp. subvillosus, the seeds were placed at three different depths (surface, 25 mm and 50 mm and subjected to fires at two different intensities (high and low. As a control sample, a batch of seeds was buried at 25 mm for the duration of the trial and not subjected to fire. Soil temperatures during the fire were compared directly to stubble quantity and indirectly related to soil depth. The two Medicago species survived exposure to 90°C for a few minutes and displayed a significant increase in germination with exposure to high temperatures (over 70°C for several minutes. On the other hand, no germination occurred in Scorpiurus, irrespective of treatment. In conclusion, fire had a significant and positive effect in triggering germination of the Medicago species, but the dispersal strategies of these hard-seeded legumes are only partially interrupted by fire as a large number of seeds (>50% remained non-germinated in the soil.

The effect of fire on the dormancy break of three annual legume seeds

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Fabio Gresta

2011-07-01

Full Text Available Fire is a common phenomenon in the Mediterranean environment and strongly influences vegetal population dynamics through its impact on vegetation and the soil seed bank. Fire is able to break down the seed coat of hard-seeded legumes within the soil and trigger germination. To evaluate the effect of fire on the dormancy break in Medicago ciliaris, Medicago rugosa and Scorpiurus muricatus subsp. subvillosus, the seeds were placed at three different depths (surface, 25 mm and 50 mm and subjected to fires at two different intensities (high and low. As a control sample, a batch of seeds was buried at 25 mm for the duration of the trial and not subjected to fire. Soil temperatures during the fire were compared directly to stubble quantity and indirectly related to soil depth. The two Medicago species survived exposure to 90°C for a few minutes and displayed a significant increase in germination with exposure to high temperatures (over 70°C for several minutes. On the other hand, no germination occurred in Scorpiurus, irrespective of treatment. In conclusion, fire had a significant and positive effect in triggering germination of the Medicago species, but the dispersal strategies of these hard-seeded legumes are only partially interrupted by fire as a large number of seeds (>50% remained non-germinated in the soil.

Germination success under different treatments and pod sowing depths in six legume species present in olive groves

International Nuclear Information System (INIS)

Siles, S.; García-Zafra, A.; Torres, J.A.; García-Fuentes, A.; Ruiz-Valenzuela, L.

2017-01-01

This study analysed the germination success of pods of six annual native legumes species: Astragalus hamosus, Medicago minima, Medicago orbicularis, Medicago polymorpha, Medicago rigidula and Scorpiurus muricatus. The use of these species has been proposed as a means of generating and improving herbaceous cover in olive groves. Germination success was studied in terms of the variability in the number of seeds germinated per pod after 18 months at two different sowing depths, on the surface (S) and buried 10 mm (B). Pods were subject to five different pre-germination treatments: chemical scarification, consisting of immersion in sulphuric acid for 15 min (S 1 5) and 20 min (S 2 0), immersion in water for 48 h (W 4 8), pod precooled to -18ºC for one month (P 1 8º) and untreated pods (Con). The results showed that the effectiveness of the different treatments and sowing depths depended on the species, and that there were no problems of ‘sibling-competition’ in any of the treatments or at any of the sowing depths. Species with larger, non-spiralled pods, such as A. hamosus or S. muricatus, or with very loosely spiralled pods such as M. orbicularis, had greater germination rates when buried, mainly in the case of untreated pods and pods that were immersed in sulphuric acid for 20 minutes.

Transcriptional profiling of Medicago truncatula under salt stress identified a novel CBF transcription factor MtCBF4 that plays an important role in abiotic stress responses

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Su Zhen

2011-07-01

Full Text Available Abstract Background Salt stress hinders the growth of plants and reduces crop production worldwide. However, different plant species might possess different adaptive mechanisms to mitigate salt stress. We conducted a detailed pathway analysis of transcriptional dynamics in the roots of Medicago truncatula seedlings under salt stress and selected a transcription factor gene, MtCBF4, for experimental validation. Results A microarray experiment was conducted using root samples collected 6, 24, and 48 h after application of 180 mM NaCl. Analysis of 11 statistically significant expression profiles revealed different behaviors between primary and secondary metabolism pathways in response to external stress. Secondary metabolism that helps to maintain osmotic balance was induced. One of the highly induced transcription factor genes was successfully cloned, and was named MtCBF4. Phylogenetic analysis revealed that MtCBF4, which belongs to the AP2-EREBP transcription factor family, is a novel member of the CBF transcription factor in M. truncatula. MtCBF4 is shown to be a nuclear-localized protein. Expression of MtCBF4 in M. truncatula was induced by most of the abiotic stresses, including salt, drought, cold, and abscisic acid, suggesting crosstalk between these abiotic stresses. Transgenic Arabidopsis over-expressing MtCBF4 enhanced tolerance to drought and salt stress, and activated expression of downstream genes that contain DRE elements. Over-expression of MtCBF4 in M. truncatula also enhanced salt tolerance and induced expression level of corresponding downstream genes. Conclusion Comprehensive transcriptomic analysis revealed complex mechanisms exist in plants in response to salt stress. The novel transcription factor gene MtCBF4 identified here played an important role in response to abiotic stresses, indicating that it might be a good candidate gene for genetic improvement to produce stress-tolerant plants.

Transcriptional profiling of Medicago truncatula under salt stress identified a novel CBF transcription factor MtCBF4 that plays an important role in abiotic stress responses

Science.gov (United States)

2011-01-01

Background Salt stress hinders the growth of plants and reduces crop production worldwide. However, different plant species might possess different adaptive mechanisms to mitigate salt stress. We conducted a detailed pathway analysis of transcriptional dynamics in the roots of Medicago truncatula seedlings under salt stress and selected a transcription factor gene, MtCBF4, for experimental validation. Results A microarray experiment was conducted using root samples collected 6, 24, and 48 h after application of 180 mM NaCl. Analysis of 11 statistically significant expression profiles revealed different behaviors between primary and secondary metabolism pathways in response to external stress. Secondary metabolism that helps to maintain osmotic balance was induced. One of the highly induced transcription factor genes was successfully cloned, and was named MtCBF4. Phylogenetic analysis revealed that MtCBF4, which belongs to the AP2-EREBP transcription factor family, is a novel member of the CBF transcription factor in M. truncatula. MtCBF4 is shown to be a nuclear-localized protein. Expression of MtCBF4 in M. truncatula was induced by most of the abiotic stresses, including salt, drought, cold, and abscisic acid, suggesting crosstalk between these abiotic stresses. Transgenic Arabidopsis over-expressing MtCBF4 enhanced tolerance to drought and salt stress, and activated expression of downstream genes that contain DRE elements. Over-expression of MtCBF4 in M. truncatula also enhanced salt tolerance and induced expression level of corresponding downstream genes. Conclusion Comprehensive transcriptomic analysis revealed complex mechanisms exist in plants in response to salt stress. The novel transcription factor gene MtCBF4 identified here played an important role in response to abiotic stresses, indicating that it might be a good candidate gene for genetic improvement to produce stress-tolerant plants. PMID:21718548

Nod Factor Effects on Root Hair-Specific Transcriptome of Medicago truncatula: Focus on Plasma Membrane Transport Systems and Reactive Oxygen Species Networks.

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Damiani, Isabelle; Drain, Alice; Guichard, Marjorie; Balzergue, Sandrine; Boscari, Alexandre; Boyer, Jean-Christophe; Brunaud, Véronique; Cottaz, Sylvain; Rancurel, Corinne; Da Rocha, Martine; Fizames, Cécile; Fort, Sébastien; Gaillard, Isabelle; Maillol, Vincent; Danchin, Etienne G J; Rouached, Hatem; Samain, Eric; Su, Yan-Hua; Thouin, Julien; Touraine, Bruno; Puppo, Alain; Frachisse, Jean-Marie; Pauly, Nicolas; Sentenac, Hervé

2016-01-01

Root hairs are involved in water and nutrient uptake, and thereby in plant autotrophy. In legumes, they also play a crucial role in establishment of rhizobial symbiosis. To obtain a holistic view of Medicago truncatula genes expressed in root hairs and of their regulation during the first hours of the engagement in rhizobial symbiotic interaction, a high throughput RNA sequencing on isolated root hairs from roots challenged or not with lipochitooligosaccharides Nod factors (NF) for 4 or 20 h was carried out. This provided a repertoire of genes displaying expression in root hairs, responding or not to NF, and specific or not to legumes. In analyzing the transcriptome dataset, special attention was paid to pumps, transporters, or channels active at the plasma membrane, to other proteins likely to play a role in nutrient ion uptake, NF electrical and calcium signaling, control of the redox status or the dynamic reprogramming of root hair transcriptome induced by NF treatment, and to the identification of papilionoid legume-specific genes expressed in root hairs. About 10% of the root hair expressed genes were significantly up- or down-regulated by NF treatment, suggesting their involvement in remodeling plant functions to allow establishment of the symbiotic relationship. For instance, NF-induced changes in expression of genes encoding plasma membrane transport systems or disease response proteins indicate that root hairs reduce their involvement in nutrient ion absorption and adapt their immune system in order to engage in the symbiotic interaction. It also appears that the redox status of root hair cells is tuned in response to NF perception. In addition, 1176 genes that could be considered as "papilionoid legume-specific" were identified in the M. truncatula root hair transcriptome, from which 141 were found to possess an ortholog in every of the six legume genomes that we considered, suggesting their involvement in essential functions specific to legumes. This

Nod factor effects on root hair-specific transcriptome of Medicago truncatula: focus on plasma membrane transport systems and reactive oxygen species networks

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Isabelle eDAMIANI

2016-06-01

Full Text Available Root hairs are involved in water and nutrient uptake, and thereby in plant autotrophy. In legumes, they also play a crucial role in establishment of rhizobial symbiosis. To obtain a holistic view of Medicago truncatula genes expressed in root hairs and of their regulation during the first hours of the engagement in rhizobial symbiotic interaction, a high throughput RNA sequencing on isolated root hairs from roots challenged or not with lipochitooligosaccharides Nod factors (NF for 4 h or 20 h was carried out. This provided a repertoire of genes displaying expression in root hairs, responding or not to NF and specific or not to legumes. In analyzing the transcriptome dataset, special attention was paid to pumps, transporters or channels active at the plasma membrane, to other proteins likely to play a role in nutrient ion uptake, NF electrical and calcium signaling, control of the redox status or the dynamic reprogramming of root hair transcriptome induced by NF treatment, and to the identification of papilionoid legume-specific genes expressed in root hairs. About 10 percent of the root hair expressed genes were significantly up- or down-regulated by NF treatment, suggesting their involvement in remodeling plant functions to allow establishment of the symbiotic relationship. For instance, NF-induced changes in expression of genes encoding plasma membrane transport systems or disease response proteins indicate that root hairs reduce their involvement in nutrient ion absorption and adapt their immune system in order to engage in the symbiotic interaction. It also appears that the redox status of root hair cells is tuned in response to NF perception. In addition, 1,176 genes that could be considered as papilionoid legume-specific were identified in the M. truncatula root hair transcriptome, from which 141 were found to possess an orthologue in every of the 6 legume genomes that we considered, suggesting their involvement in essential functions

In silico identification of transcription factors in medicago sativa using available transcriptomic resources

Science.gov (United States)

Functional genomics of alfalfa, the most extensively cultivated forage legume in the world, is in the developing stage. Although alfalfa genome sequence is not yet completed, several large transcriptomic resources that can be used to identify genes and determine the amount of their activity are free...

Doenças foliares da alfafa (Medicago sativa L., em Lavras, Minas Gerais

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Pereira Rosana Cristina

2003-01-01

Full Text Available Objetivou-se verificar as doenças foliares que ocorrem na alfafa em Lavras-MG, no período de setembro de 1997 a outubro de 1998. Um ensaio foi conduzido em blocos ao acaso em esquema de parcelas subdivididas. Nas parcelas foram alocadas foram 35 cultivares e nas subparcelas 11 épocas de avaliação. Avaliações foram realizadas aos 28 dias após corte, quando foram coletadas dez hastes de alfafa por parcela para avaliação da desfolha e determinação da severidade das doenças. Os dados foram submetidos à análise de variância e os contrastes entre médias comparados pelo teste de Scott-Knott a 5%. A mancha-de-Leptosphaerulina ocorreu durante o ano todo, porém com maior severidade nos períodos mais frios do ano. A mancha-negra-das-folhas-e-caule apresentou maior severidade no final do verão e início do outono e a ferrugem revelou maior severidade apenas nas avaliações de novembro. As maiores porcentagens de desfolha foram obtidas nos meses mais frios do ano. As cultivares mais resistentes à mancha-de-Leptosphaerulina, cercosporiose e à desfolha foram a Crioula, P30 e Costera SP INTA. As cultivares MH 15 e MH 4 destacaram-se pela maior resistência à ferrugem.

Uso del agua en la alfalfa (Medicago sativa con riego por goteo subsuperficial

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José Alfredo Montemayor Trejo

2010-01-01

Full Text Available Con el objetivo de analizar la eficiencia en el uso del agua con el sistema de riego por goteo subsuperficial y por gravedad, durante el año 2004 se realizó la investigación en la Comarca Lagunera de los estados de Coahuila y Durango, México. Se estableció un diseño de bloques al azar con cuatro repeticiones y tres tratamientos de separación de cintas de riego de 0.8, 0.9 y 1.0 m, y como testigo se evaluó el método de riego por gravedad. Se utilizó el método de regresión lineal simple entre las variables días después de siembra y lámina de agua aplicada, para obtener modelos de aplicación de agua con riego por goteo subsuperficial (RGS y riego por gravedad. La variedad de alfalfa establecida fue la WL 712 con una densidad de siembra de 40 kg ha-1, el gasto de la cinta fue de 3 L/h por metro lineal con orificios espaciados a 30 cm y espesor de 10,000 micrones. La lámina de riego aplicada fue de 1.39 m en el sistema por gravedad y 1.16 m con riego por goteo subsuperficial. Los consumos de agua promedio diario de los modelos presentaron diferencias t(a=0.05 y fueron 0.417 y 0.299 cm dia-1 en gravedad y RGS. El rendimiento de materia seca en siete cortes y la eficiencia en el uso del agua fueron de 24.08 t ha-1, 2.04 kg m-3 en subsuperficial y 18.46 t ha-1, 1.33 kg m-3 en gravedad (P<0.05.

The physiological effect of fluorene on Triticum aestivum, Medicago sativa, and Helianthus annus

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Seyed Yahya Salehi-Lisar

2015-12-01

Full Text Available Polycyclic aromatic hydrocarbons (PAHs are widespread pollutants and can negatively affect plants. Fluorene is a prevalent PAH in the contaminated environment. In this study, the effects of higher concentrations of fluorene in soil on rate of seed germination, growth, and the physiological parameters of wheat, sunflower, and alfalfa were studied. The results showed that the higher concentration of fluorene decreased rate of seed germination and seedlings growth of plants. Wheat showed the highest resistance at seed germination and seedlings growth phases, and sunflower was the most sensitive species at both stages. Therefore, it was concluded that higher resistance at seed germination could be followed by the higher resistance of seedlings. Fluorene toxicity also induced oxidative stress in plants as shown by MDA accumulation in the plants. There was a significant correlation between the lower activity of CAT and MDA accumulation in the studied plants. Therefore, CAT could be an important enzyme involved in detoxification of ROS and plants resistance to fluorene toxicity. Depending on plant species and fluorene concentration, photosynthetic pigments content was differently affected.

Investigation of Antileishmanial Effect of Alcoholic Extract and Essential Oil of Medicinal Plant Leaf Black Alfalfa (Medicago Lupulina, on The Number of Clinical Isolates of Leishmania Major Promastigotes in Vitro

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E Gharirvand Eskandari

2016-05-01

Full Text Available Introduction: Leishmaniasis has created enormous global health problems. Side effects, drug resistance and the lack of effective vaccines had led to the new effective compounds effective of plants. The aim of this study was to introduce a traditional medicinal plant called Black alfalfa (Medicago Lupulina that can be used as a valuable resource against cutaneous leishmaniasis. Methods: In this experimental study, alcoholic extract was prepared by maceration and essential oil by distillation water method. Leishmania major promastigotes were cultured at 25 ± 2° C in N.N.N culturemedium, then in Schneider and next were cultured in RPMI- 1640. afterward, using MTT (Methyl Thiazole Tetrazolium, the IC50 (Inhibitory Concentrations 50% for extracts, essence and Glucantime were determined. The results using Tukey and t-test were analyzed and were presented by software SPSS16. MTT assay were repeated. 3 times for each sample. Results: IC50 for alfalfa leaf extract and essential oil of black alfalfa and Glucantime against L. major promastigotes was determined after 24, 48 and 72 hours, 240, 130 and 69 micrograms per ml, and 801, 340 and 190 micrograms per ml, also 26, 19 and 11 micrograms per ml , respectively. There was a significant differences between the IC50 plant extract and essential oil and Glucantime after 24, 48 and 72 hours. Conclusion: Alcoholic extracts and essential oil the plant had significant anti leishmaniasis effects in vitro. In this way, it can be considered as an anti-leishmaniasis among the herbs.

[Comparison of soil fertility among open-pit mine reclaimed lands in Antaibao regenerated with different vegetation types].

Science.gov (United States)

Wang, Xiang; Li, Jin-chuan; Yue, Jian-ying; Zhou, Xiao-mei; Guo, Chun-yan; Lu, Ning; Wang, Yu-hong; Yang, Sheng-quan

2013-09-01

Re-vegetation is mainly applied into regeneration in opencast mine to improve the soil quality. It is very important to choose feasible vegetation types for soil restoration. In this study, three typical forest restoration types were studied at Antaibao mine, namely, Medicago sativa, mixed forests Pinus taebelaefolius-Robinia pseudoacacia-Caragana korshinskii and Elaeagnus angustifolia-Robinia pseudoacacia-Caragana korshinskii-Hipophae rhamnoides, to determine the nutrient contents and enzyme activities in different soil layers. The results showed that re-vegetation markedly increased soil nutrient contents and the enzyme activities during the restoration process. The nutrient content of soil in the P. taebelaefolius-R. pseudoacacia-C. korshinskii mixed forest field was significantly higher than those in other plots. It was found that the soil of the P. taebelaefolius-R. pseudoacacia-C. korshinskii mixed forest had the highest integrated fertility index values. In conclusion, the restoration effects of the P. zaebelaefolius-R. pseudoacacia-C. Korshinskii mixed forest was better than that of E. angustifolia-R. pseudoacacia-C. korshinskii-H. rhamnoides, while M. sativa grassland had the least effect.

Comparative transcriptional profiling provides insights into the evolution and development of the zygomorphic flower of Vicia sativa (Papilionoideae.

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Zhipeng Liu

Full Text Available BACKGROUND: Vicia sativa (the common vetch possesses a predominant zygomorphic flower and belongs to the subfamily Papilionoideae, which is related to Arabidopsis thaliana in the eurosid II clade of the core eudicots. Each vetch flower consists of 21 concentrically arranged organs: the outermost five sepals, then five petals and ten stamens, and a single carpel in the center. METHODOLOGY/PRINCIPAL FINDINGS: We explored the floral transcriptome to examine a genome-scale genetic model of the zygomorphic flower of vetch. mRNA was obtained from an equal mixture of six floral organs, leaves and roots. De novo assembly of the vetch transcriptome using Illumina paired-end technology produced 71,553 unigenes with an average length of 511 bp. We then compared the expression changes in the 71,553 unigenes in the eight independent organs through RNA-Seq Quantification analysis. We predominantly analyzed gene expression patterns specific to each floral organ and combinations of floral organs that corresponded to the traditional ABC model domains. Comparative analyses were performed in the floral transcriptomes of vetch and Arabidopsis, and genomes of vetch and Medicago truncatula. CONCLUSIONS/SIGNIFICANCE: Our comparative analysis of vetch and Arabidopsis showed that the vetch flowers conform to a strict ABC model. We analyzed the evolution and expression of the TCP gene family in vetch at a whole-genome level, and several unigenes specific to three different vetch petals, which might offer some clues toward elucidating the molecular mechanisms underlying floral zygomorphy. Our results provide the first insights into the genome-scale molecular regulatory network that controls the evolution and development of the zygomorphic flower in Papilionoideae.

Two alternative recessive quantitative trait loci influence resistance to spring black stem and leaf spot in Medicago truncatula

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Oliver Richard P

2008-03-01

Full Text Available Abstract Background Knowledge of the genetic basis of plant resistance to necrotrophic pathogens is incomplete and has been characterised in relatively few pathosystems. In this study, the cytology and genetics of resistance to spring black stem and leaf spot caused by Phoma medicaginis, an economically important necrotrophic pathogen of Medicago spp., was examined in the model legume M. truncatula. Results Macroscopically, the resistant response of accession SA27063 was characterised by small, hypersensitive-like spots following inoculation while the susceptible interaction with accessions A17 and SA3054 showed necrotic lesions and spreading chlorosis. No unique cytological differences were observed during early infection (2 populations segregating for resistance to spring black stem and leaf spot were established between SA27063 and the two susceptible accessions, A17 and SA3054. The cross between SA27063 and A17 represented a wider cross than between SA27063 and SA3054, as evidenced by higher genetic polymorphism, reduced fertility and aberrant phenotypes of F2 progeny. In the SA27063 × A17 F2 population a highly significant quantitative trait locus (QTL, LOD = 7.37; P Phoma medicaginis one (rnpm1 genetically mapped to the top arm of linkage group 4 (LG4. rnpm1 explained 33.6% of the phenotypic variance in the population's response to infection depicted on a 1–5 scale and was tightly linked to marker AW256637. A second highly significant QTL (LOD = 6.77; P rnpm2, was located on the lower arm of LG8 in the SA27063 × SA3054 map. rnpm2 explained 29.6% of the phenotypic variance and was fine mapped to a 0.8 cM interval between markers h2_16a6a and h2_21h11d. rnpm1 is tightly linked to a cluster of Toll/Interleukin1 receptor-nucleotide binding site-leucine-rich repeat (TIR-NBS-LRR genes and disease resistance protein-like genes, while no resistance gene analogues (RGAs are apparent in the genomic sequence of the reference accession A17 at the

The uptake, distribution and translocation of 86Rb in alfalfa plants susceptible and resistant to the bacterial wilt and the effect of Corynebacterium insidiosum upon these processes

International Nuclear Information System (INIS)

Hanker, I.; Kudelova, A.

1981-01-01

Alfalfa (Medicago sativa L.) plants susceptible (S) and resistant (R) to bacterial wilt were fed via roots with a nutrient solution labelled with 86 Rb + , at different times after inoculation with Corynebacterium insidiosum (McCull.) H.L. Jens. The infection did not affect 86 Rb + uptake per plant in the course of a 14-day-period following inoculation; however, it affected its distribution differently in the S- and the R-plants. 86 Rb + uptake significantly decreased due to the infection in the S-plants on the day 49 after inoculation (a 4-h-exposure to 86 Rb + ), with the ions more slowly translocated to the shoots in diseased S-plants than in diseased R-plants. Likely factors causing these effects and their relationship to alfalfa resistance to bacterial wilt are discussed. (author)

Legume Seed Production Meeting Market Requirements and Economic Impacts

DEFF Research Database (Denmark)

Boelt, Birte; Julier, Bernadette; Karagić, Đura

2015-01-01

The seed is the carrier of the genetic improvements brought about by modern plant breeding, and seed production is carried out in accordance with certification systems to guarantee consistent high quality. In forage legumes, breeding efforts are primarily related to the vegetative development...... of the plant, although the commercial success of an agronomically superior cultivar is dependent on a reliable supply of competitively priced seed. In seed production of the three most important forage legumes, alfalfa (Medicago sativa L.), white clover (Trifolium repens L.), and red clover (Trifolium pratense......-pollinated forage legumes it is further highly influenced by environmental conditions and crop management factors. Further investigations into the use of plant growth regulators and an improved understanding of the interaction between pollinators and the seed crop might improve future seed yields. There is likely...

Phytotoxicity of citric acid and Tween® 80 for potential use as soil amendments in enhanced phytoremediation.

Science.gov (United States)

Agnello, A C; Huguenot, D; van Hullebusch, E D; Esposito, G

2015-01-01

Enhanced phytoremediation adding biodegradable amendments like low molecular weight organic acids and surfactants is an interesting area of current research to overcome the limitation that represents low bioavailability of pollutants in soils. However, prior to their use in assisted phytoremediation, it is necessary to test if amendments per se exert any toxic effect to plants and to optimize their application mode. In this context, the present study assessed the effects of citric acid and Tween® 80 (polyethylene glycol sorbitan monooleate) on the development of alfalfa (Medicago sativa) plants, as influenced by their concentration and frequency of application, in order to evaluate the feasibility for their future use in enhanced phytoremediation of multi-contaminated soils. The results showed that citric acid negatively affected plant germination, while it did not have any significant effect on biomass or chlorophyll content. In turn, Tween® 80 did not affect plant germination and showed a trend to increase biomass, as well as it did not have any significant effect on chlorophyll levels. M. sativa appeared to tolerate citric acid and Tween® 80 at the tested concentrations, applied weekly. Consequently, citric acid and Tween® 80 could potentially be utilized to assist phytoremediation of contaminated soils vegetated with M. sativa.

The response of some common Egyptian plants to ozone and their use as biomonitors.

Science.gov (United States)

El-Khatib, A A

2003-01-01

Relative sensitivity of five common Egyptian plant species namely, Senecio vulgaris, Malva parviflora, Sonchus oleraceus, Medicago sativa and Melilotus indicus to elevated levels of ozone has been studied. The plants were exposed to charcoal filtered air (CFA) and different levels of O3 (50 and 100 ppb) for 5 h per day. The studied parameters were recorded for five consecutive days after fumigation. The foliar injury varied significantly among species in a dose-dependent manner. Severe injury symptoms were recorded on the leaves of M. sativa. With the exception of M. parviflora, all species exhibited significant increases in the percentage reduction of the above-ground dry weight as a result of reductions in both leaf and stem dry weights. M. sativa showed a marked reduction in its relative growth rate at elevated levels of O3. The extent of chlorophyll a destruction was higher in both M. sativa and S. oleraceus than in the other species tested. No differences in the sensitivity of chlorophylls a+b and carotenoids to ozone levels were recorded in this work. Percentage reduction of ascorbic acid was higher in M. sativa and S. oleraceus, compared with the other species studied. With respect to relative percentages of proline, there was a significant difference in the responses of plants to ozone. According to the ozone resistance (R%), measured as relative growth rate, the test species were arranged in the descending order: M. parviflora>M. Indicus>S. Vulgaris>S. Oleraceus>M. sativa. In M. sativa, both determinant and correlation coefficients are well reflected in the relationship between its physiological response, its performance and ozone levels, supporting its recommendation as a candidate for biomonitoring in Egypt.

Dicty_cDB: VSA784 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available tula EST MtBC39A08F1 : T3 end of clone MtBC39A08 of cDNA library MtBC from arbuscular mycorrhiza of cultivar...C10B03F1 : T3 end of clone MtBC10B03 of cDNA library MtBC from arbuscular mycorrh... cDNA library MtBC from arbuscular mycorrhiza of cultivar Jemalong of Medicago truncatula (barrel medic). 62...13 |AL382813.1 Medicago truncatula EST MtBC10B03R1 : T7 end of clone MtBC10B03 of

The effect of dietary protein on reproduction in the mare. I. The composition and evaluation of the digestibility of dietary protein from different sources

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F.E. Van Niekerk

1997-07-01

Full Text Available Four rations that differed in their crude protein and essential amino-acid content were compiled. Digestibility of the crude protein and essential amino-acid contents were determined biologically in a feeding trial using 4 Anglo-Arab stallions. Their respective daily diets were: Diet 1: 2 kg cubes, 5 kg tef hay (Eragrostis tef; Diet 2: 2 kg cubes, 5 kg lucerne hay (Medicago sativa; Diet 3: 2 kg cubes, 5 kg tef hay, 200 g fishmeal; Diet 4: 2 kg cubes, 5 kg lucerne hay, 200 g fishmeal. The concentrations of the amino-acids threonine, iso-leucine, leucine and arginine were increased in the total ration when lucerne hay replaced the tef hay while fishmeal supplementation increased the methionine and lysine contents, which provided a wide range of concentrations of digestible amino-acids in each of the 4 rations.

In vitro digestibility of lucerne hay using bag method

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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.

The Occurrence, Biosynthesis, and Molecular Structure of Proanthocyanidins and Their Effects on Legume Forage Protein Precipitation, Digestion and Absorption in the Ruminant Digestive Tract

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Arjan Jonker

2017-05-01

Full Text Available Forages grown in temperate regions, such as alfalfa (Medicago sativa L. and white clover (Trefolium repens L., typically have a high nutritional value when fed to ruminants. Their high protein content and degradation rate result, however, in poor utilization of protein from the forage resulting in excessive excretion of nitrogen into the environment by the animal. Proanthocyanindins (also known as condensed tannins found in some forage legumes such as birdsfoot trefoil (Lotus corniculatus L., bind to dietary protein and can improve protein utilization in the animal. This review will focus on (1 the occurrence of proanthocyanidins; (2 biosynthesis and structure of proanthocyanidins; (3 effects of proanthocyanidins on protein metabolism; (4 protein precipitating capacity of proanthocyanidins and their effects on true intestinal protein adsorption by ruminants; and (5 effect on animal health, animal performance and environmental emissions.

Effects of species diversity on seasonal variation in herbage yield and nutritive value of seven binary grass-legume mixtures and pure grass under cutting

DEFF Research Database (Denmark)

Elgersma, Anjo; Søegaard, Karen

2016-01-01

Intensively managed sown temperate grasslands are generally of low species diversity, although swards based on grass-legume mixtures may have superior productivity and herbage quality than grass-only swards. We conducted a cutting experiment over two years to test the effect of species composition...... and diversity on herbage yield, contents of N, neutral detergent fibre (NDF) and in vitro organic matter digestibility (IVOMD). Perennial ryegrass (PR, Lolium perenne) was sown alone and with each of four forage legumes: red clover (RC, Trifolium pratense), lucerne (LU, Medicago sativa), birdsfoot trefoil (BT......, Lotus corniculatus) and white clover (WC, Trifolium repens); WC was also sown with hybrid ryegrass (HR, Lolium × boucheanum), meadow fescue (MF, Festuca pratensis) and timothy (TI, Phleum pratense). Herbage productivity was lowest in pure PR followed by PR/BT, and highest in PR/RC; this mixture had...

Biological effects and RAPD analysis of alfalfa (medicago sativa L.) irradiated by fast neutrons

International Nuclear Information System (INIS)

Han Weibo; Zhang Yuexue; Tang Fenglan; Liu Jielin; Liu Fengqi; Shang Chen; Kong Fuquan; Wang Xiao; Liu Luxiang

2011-01-01

Dry seeds of alfalfa variety Zhaodong were irradiated by fast neutrons generated by linear accelerator with three fluences, 3.60 × 10 11 , 7.10 × 10 11 and 3.54 × 10 12 /cm 2 respectively. Seed germination, growth, and RAPD analysis on the mutation were reported in this study. The results showed that germination vigor and germination rate of irradiated seeds were higher than those of control, but seedling height and root length were reduced with the increase of fluences. When the dosages reached 3.54 × 10 12 /cm 2 , seedling root length decreased by 81.63% compared with the control, but the seedling didn't grow any true leaves except for cotyledon. 36 primers were used in RAPD analysis, and the results showed that the RAPD polymorphic loci rate was 7.25%, 6.52% and 5.80% among the 3.60 × 10 11 /cm 2 , 7.10 × 10 11 /cm 2 and 3.54 × 10 12 /cm 2 treated M 1 plants. RAPD polymorphic loci rate in the 3.60 × 10 11 /cm 2 treated plants was the highest among three treatment. It is concluded that 3.60 × 10 11 /cm 2 could be on optimum fluences for a alfalfa mutation by fast neutrons. (authors)

Boosting Alfalfa (Medicago sativa L. Production With Rhizobacteria From Various Plants in Saudi Arabia

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Ihsanullah Daur

2018-04-01

Full Text Available This study focused on rhizobacteria to promote sustainable crop production in arid regions of Saudi Arabia. The study isolated 17 tightly root-adhering rhizobacteria from various plants at Hada Al Sham in Saudi Arabia. All 17 rhizobacterial isolates were confirmed as plant growth promoting rhizobacteria by classical biochemical tests. Using 16S rDNA gene sequence analyses, the strains were identified as Bacillus, Acinetobacter and Enterobacter. Subsequently, the strains were assessed for their ability to improve the physiology, nutrient uptake, growth, and yield of alfalfa plants grown under desert agriculture conditions. The field trials were conducted in a randomized complete block design. Inoculation of alfalfa with any of these 17 strains improved the relative water content; chlorophyll a; chlorophyll b; carotenoid contents; nitrogen (N, phosphorus, and potassium contents; plant height; leaf-to-stem ratio; and fresh and dry weight. Acinetobacter pittii JD-14 was most effective to increase fresh and dry weight of alfalfa by 41 and 34%, respectively, when compared to non-inoculated control plants. Nevertheless, all strains enhanced crop traits when compared to controls plants, indicating that these desert rhizobacterial strains could be used to develop an eco-friendly biofertilizer for alfalfa and possibly other crop plants to enhance sustainable production in arid regions.

Boosting Alfalfa (Medicago sativa L.) Production With Rhizobacteria From Various Plants in Saudi Arabia

KAUST Repository

Daur, Ihsanullah; Saad, Maged; Eida, Abdul Aziz; Ahmad, Shakeel; Shah, Zahid Hussain; Ihsan, Muhammad Z.; Muhammad, Yasir; Sohrab, Sayed S.; Hirt, Heribert

2018-01-01

This study focused on rhizobacteria to promote sustainable crop production in arid regions of Saudi Arabia. The study isolated 17 tightly root-adhering rhizobacteria from various plants at Hada Al Sham in Saudi Arabia. All 17 rhizobacterial isolates were confirmed as plant growth promoting rhizobacteria by classical biochemical tests. Using 16S rDNA gene sequence analyses, the strains were identified as Bacillus, Acinetobacter and Enterobacter. Subsequently, the strains were assessed for their ability to improve the physiology, nutrient uptake, growth, and yield of alfalfa plants grown under desert agriculture conditions. The field trials were conducted in a randomized complete block design. Inoculation of alfalfa with any of these 17 strains improved the relative water content; chlorophyll a; chlorophyll b; carotenoid contents; nitrogen (N), phosphorus, and potassium contents; plant height; leaf-to-stem ratio; and fresh and dry weight. Acinetobacter pittii JD-14 was most effective to increase fresh and dry weight of alfalfa by 41 and 34%, respectively, when compared to non-inoculated control plants. Nevertheless, all strains enhanced crop traits when compared to controls plants, indicating that these desert rhizobacterial strains could be used to develop an eco-friendly biofertilizer for alfalfa and possibly other crop plants to enhance sustainable production in arid regions.

Boosting Alfalfa (Medicago sativa L.) Production With Rhizobacteria From Various Plants in Saudi Arabia.

Science.gov (United States)

Daur, Ihsanullah; Saad, Maged M; Eida, Abdul Aziz; Ahmad, Shakeel; Shah, Zahid Hussain; Ihsan, Muhammad Z; Muhammad, Yasir; Sohrab, Sayed S; Hirt, Heribert

2018-01-01

This study focused on rhizobacteria to promote sustainable crop production in arid regions of Saudi Arabia. The study isolated 17 tightly root-adhering rhizobacteria from various plants at Hada Al Sham in Saudi Arabia. All 17 rhizobacterial isolates were confirmed as plant growth promoting rhizobacteria by classical biochemical tests. Using 16S rDNA gene sequence analyses, the strains were identified as Bacillus, Acinetobacter and Enterobacter . Subsequently, the strains were assessed for their ability to improve the physiology, nutrient uptake, growth, and yield of alfalfa plants grown under desert agriculture conditions. The field trials were conducted in a randomized complete block design. Inoculation of alfalfa with any of these 17 strains improved the relative water content; chlorophyll a; chlorophyll b; carotenoid contents; nitrogen (N), phosphorus, and potassium contents; plant height; leaf-to-stem ratio; and fresh and dry weight. Acinetobacter pittii JD-14 was most effective to increase fresh and dry weight of alfalfa by 41 and 34%, respectively, when compared to non-inoculated control plants. Nevertheless, all strains enhanced crop traits when compared to controls plants, indicating that these desert rhizobacterial strains could be used to develop an eco-friendly biofertilizer for alfalfa and possibly other crop plants to enhance sustainable production in arid regions.

Boosting Alfalfa (Medicago sativa L.) Production With Rhizobacteria From Various Plants in Saudi Arabia

KAUST Repository

Daur, Ihsanullah

2018-04-04

This study focused on rhizobacteria to promote sustainable crop production in arid regions of Saudi Arabia. The study isolated 17 tightly root-adhering rhizobacteria from various plants at Hada Al Sham in Saudi Arabia. All 17 rhizobacterial isolates were confirmed as plant growth promoting rhizobacteria by classical biochemical tests. Using 16S rDNA gene sequence analyses, the strains were identified as Bacillus, Acinetobacter and Enterobacter. Subsequently, the strains were assessed for their ability to improve the physiology, nutrient uptake, growth, and yield of alfalfa plants grown under desert agriculture conditions. The field trials were conducted in a randomized complete block design. Inoculation of alfalfa with any of these 17 strains improved the relative water content; chlorophyll a; chlorophyll b; carotenoid contents; nitrogen (N), phosphorus, and potassium contents; plant height; leaf-to-stem ratio; and fresh and dry weight. Acinetobacter pittii JD-14 was most effective to increase fresh and dry weight of alfalfa by 41 and 34%, respectively, when compared to non-inoculated control plants. Nevertheless, all strains enhanced crop traits when compared to controls plants, indicating that these desert rhizobacterial strains could be used to develop an eco-friendly biofertilizer for alfalfa and possibly other crop plants to enhance sustainable production in arid regions.

Quantitation of pyrimidine dimers in DNA from UVB-irradiated alfalfa (Medicago sativa L.) seedlings

International Nuclear Information System (INIS)

Quaite, F.E.; Sutherland, B.M.; Sutherland, J.C.

1991-01-01

Depletion of stratospheric ozone will increase the solar ultraviolet radiation in the range from 290-320 nm (UVB) that reaches the surface of the earth, placing an increased UV burden on exposed organisms. One consequence of increased UVB may be decreased productivity of crop plants. A principal lesion caused by UV in DNA is the cyclobutyl pyrimidine dimer. We have adapted a method for measuring these dimers in nanogram quantities of non-radioactive DNA for use in UV-irradiated plants. We find that biologically relevant doses of broad band UVB radiation induce easily detectable frequencies of pyrimidine dimers in the DNA of irradiated alfalfa sprout leaves and that the dose response for dimer formation is linear up to doses of at least 690 J/m 2 . We also find easily measurable frequencies of dimers in the leaves of seedlings grown in glass filtered sunlight but not exposed to additional UVB, suggesting that significant number of dimers are formed in plants exposed to normal sunlight. 27 refs., 3 figs., 1 tab

Seed Priming to Overcome Salinity Stress in Persian Cultivars of Alfalfa (Medicago sativa L.

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Ali SEPEHRI

2015-03-01

Full Text Available In order to investigate the effect of hydro-priming on seed germination with distilled water on germination of five Alfalfa cultivars under salinity stress, an experiment was conducted as a factorial experiment based on a completely randomized design with three replications. Seven levels of hydro-priming and salinity of NaCl including prime and non-salinity, prime and 50 mM salinity, prime and 100 mM salinity, prime and 150 mM salinity, prime and 200 mM salinity, prime and 250 mM salinity and without prime and salinity and five alfalfa varieties, including ‘Hamedani’, ‘Isfahani’, ‘Bami’, ‘Yazdi’ and ‘Ghareh Yonjeh’ were used. The results showed that the main effect of prime, salinity and cultivars and their interaction in all studied traits were significantly affected at the 5% probability level. Priming treatments in non-salinity of all cultivars were the highest. In all cultivars, final germination percentage, length and weight of radicle, plumule and seedling, germination rate and time, relative radicle elongation, vigor index and stress index, were significantly improved in response to priming in salinity levels of 50-200 mM, compared to control. Radicle produced higher length and weight than the plumule in hydro- priming and salinity treatments. ‘Hamedani’ cultivar in most of studied characteristics had a better response than others. The lowest response to salinity stress and priming was observed in ‘Yazdi’ cultivar.

IMPLEMENTATION OF DNA MARKERS TO IMPROVE BREEDING OF FORAGE LEGUMES

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S. Grljušić

2008-09-01

Full Text Available The low rates of estimated genetic gains in forage legumes breeding have emphasized the need for new breeding methods that would increase efficiency in forage selection and provide reliable improvement. Information on application of molecular methodologies and tools for the enhancement of the current empirical phenotype-based selection moved us toward implementation of DNA markers to our breeding activities. Firstly, attention was given to identification of genetic variability within the forage species involved in program and comparison of conventional and molecular marker efficiency in variability evaluation. RAPDs were used (i to estimate availability of alfalfa (Medicago sativa L. and Medicago falcata L. genetic variation and (ii to identify changes of red clover (Trifolium pratense L. variability after natural selection. SSRs were applied to evaluate diversity within and among field pea (Pisum sativum L. var. arvense and sativum groups/varieties. A total of 90 (alfalfa or 92 (red clover polymorphic bands was found by RAPDs. Total number of SSR alleles recorded was 118. The average Roger's distance per species/genus estimated was 0.29 (red clover, 0.33 (alfalfa and 0.51 (field pea. 2D PCo analysis of each species/genus separated materials into respective groups. A high degree of genetic variation within populations/varieties of each investigated species was found by AMOVA. The correspondence between pairs of matrices based on the morphological and molecular data was significant (p=0.95 only for red clover. RAPD and SSR data have given valuable information on genetic structure of materials and provided a description that determines heterogeneity. Further studies will be focused on identifying quantitative trait loci and marker assisted selection.

The response of some common Egyptian plants to ozone and their use as biomonitors

International Nuclear Information System (INIS)

El-Khatib, A.A.

2003-01-01

Growth and physiological response of plants was shown to be an effective tool for O 3 -biomonitoring. - Relative sensitivity of five common Egyptian plant species namely, Senecio vulgaris, Malva parviflora, Sonchus oleraceus, Medicago sativa and Melilotus indicus to elevated levels of ozone has been studied. The plants were exposed to charcoal filtered air (CFA) and different levels of O 3 (50 and 100 ppb) for 5 h per day. The studied parameters were recorded for five consecutive days after fumigation. The foliar injury varied significantly among species in a dose-dependent manner. Severe injury symptoms were recorded on the leaves of M. sativa. With the exception of M. parviflora, all species exhibited significant increases in the percentage reduction of the above-ground dry weight as a result of reductions in both leaf and stem dry weights. M. sativa showed a marked reduction in its relative growth rate at elevated levels of O 3 . The extent of chlorophyll a destruction was higher in both M. sativa and S. oleraceus than in the other species tested. No differences in the sensitivity of chlorophylls a+b and carotenoids to ozone levels were recorded in this work. Percentage reduction of ascorbic acid was higher in M. sativa and S. oleraceus, compared with the other species studied. With respect to relative percentages of proline, there was a significant difference in the responses of plants to ozone. According to the ozone resistance (R%), measured as relative growth rate, the test species were arranged in the descending order: M. parviflora>M. Indicus>S. Vulgaris>S. Oleraceus>M. sativa. In M. sativa, both determinant and correlation coefficients are well reflected in the relationship between its physiological response, its performance and ozone levels, supporting its recommendation as a candidate for biomonitoring in Egypt

The response of some common Egyptian plants to ozone and their use as biomonitors

Energy Technology Data Exchange (ETDEWEB)

El-Khatib, A A

2003-08-01

Growth and physiological response of plants was shown to be an effective tool for O{sub 3}-biomonitoring. - Relative sensitivity of five common Egyptian plant species namely, Senecio vulgaris, Malva parviflora, Sonchus oleraceus, Medicago sativa and Melilotus indicus to elevated levels of ozone has been studied. The plants were exposed to charcoal filtered air (CFA) and different levels of O{sub 3} (50 and 100 ppb) for 5 h per day. The studied parameters were recorded for five consecutive days after fumigation. The foliar injury varied significantly among species in a dose-dependent manner. Severe injury symptoms were recorded on the leaves of M. sativa. With the exception of M. parviflora, all species exhibited significant increases in the percentage reduction of the above-ground dry weight as a result of reductions in both leaf and stem dry weights. M. sativa showed a marked reduction in its relative growth rate at elevated levels of O{sub 3}. The extent of chlorophyll a destruction was higher in both M. sativa and S. oleraceus than in the other species tested. No differences in the sensitivity of chlorophylls a+b and carotenoids to ozone levels were recorded in this work. Percentage reduction of ascorbic acid was higher in M. sativa and S. oleraceus, compared with the other species studied. With respect to relative percentages of proline, there was a significant difference in the responses of plants to ozone. According to the ozone resistance (R%), measured as relative growth rate, the test species were arranged in the descending order: M. parviflora>M. Indicus>S. Vulgaris>S. Oleraceus>M. sativa. In M. sativa, both determinant and correlation coefficients are well reflected in the relationship between its physiological response, its performance and ozone levels, supporting its recommendation as a candidate for biomonitoring in Egypt.

A cold-induced myo-inositol transporter-like gene confers tolerance to multiple abiotic stresses in transgenic tobacco plants.

Science.gov (United States)

Sambe, Mame Abdou Nahr; He, Xueying; Tu, Qinghua; Guo, Zhenfei

2015-03-01

A full length cDNA encoding a myo-inositol transporter-like protein, named as MfINT-like, was cloned from Medicago sativa subsp. falcata (herein falcata), a species with greater cold tolerance than alfalfa (M. sativa subsp. sativa). MfINT-like is located on plasma membranes. MfINT-like transcript was induced 2-4 h after exogenous myo-inositol treatment, 24-96 h with cold, and 96 h by salinity. Given that myo-inositol accumulates higher in falcata after 24 h of cold treatment, myo-inositol is proposed to be involved in cold-induced expression of MfINT-like. Higher levels of myo-inositol was observed in leaves of transgenic tobacco plants overexpressing MfINT-like than the wild-type but not in the roots of plants grown on myo-inositol containing medium, suggesting that transgenic plants had higher myo-inositol transport activity than the wild-type. Transgenic plants survived better to freezing temperature, and had lower ion leakage and higher maximal photochemical efficiency of photosystem II (Fv /Fm ) after chilling treatment. In addition, greater plant fresh weight was observed in transgenic plants as compared with the wild-type when plants were grown under drought or salinity stress. The results suggest that MfINT-like mediated transport of myo-inositol is associated with plant tolerance to abiotic stresses. © 2014 Scandinavian Plant Physiology Society.

Degradabilidade ruminal da matéria seca, da fração fibrosa e da proteína bruta de forrageiras Forages dry matter, fibrous fraction and crude protein ruminal degradability

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Aureliano José Vieira Pires

2006-04-01

Full Text Available O objetivo deste trabalho foi avaliar a degradabilidade ruminal da matéria seca, da fibra em detergente neutro, da fibra em detergente ácido e da proteína bruta da alfafa (Medicago sativa, aveia-preta (Avena strigosa, leucena (Leucaena leucocephala e guandu (Cajanus cajan. Amostras de 3 g das forragens foram incubadas no rúmen de três novilhos por períodos de 0, 6, 12, 24, 36, 48 e 72 horas. As degradabilidades efetivas da matéria seca da alfafa e da aveia, para a taxa de passagem de 5% por hora, foram elevadas (acima de 60%. A leucena e o guandu apresentaram valores inferiores, 50,9 e 56,0%, respectivamente. A partir de 24 horas de incubação, a aveia se destacou com maior desaparecimento da fibra em detergente neutro e da fibra em detergente ácido, e ainda apresentou as mais elevadas taxas de degradação efetiva destas frações. A aveia foi a forragem que apresentou maior degradabilidade da matéria seca, da fibra em detergente neutro, da fibra em detergente ácido e da proteína bruta no rúmen. O guandu, entretanto, foi a forragem com as piores taxas de degradação.The objective of this work was to evaluate ruminal degradability of dry matter, neutral detergent fiber, acid detergent fiber and crude protein of alfalfa (Medicago sativa, black oat (Avena strigosa, leucaena (Leucaena leucocephala and pigeon pea (Cajanus cajan. Samples of 3 g of forages were incubated in the rumen of three steers for 0, 6, 12, 24, 36, 48 and 72 hours periods. The dry matter effective degradabilities of alfalfa and oat, for a passage rate of 5%/hour, were high (over 60%. However, leucaena and pigeon pea showed lower values, 50.9 and 56.0%, respectively. From 24-hour incubation period on, the oat presented the highest neutral detergent fiber and acid detergent fiber disappearance and showed the greatest effective degradation rates of these fractions. The oat was the forage with the highest dry matter, neutral detergent fiber, acid detergent fiber and

Trans-specific gene silencing of acetyl-CoA carboxylase in a root-parasitic plant.

Science.gov (United States)

Bandaranayake, Pradeepa C G; Yoder, John I

2013-05-01

Parasitic species of the family Orobanchaceae are devastating agricultural pests in many parts of the world. The control of weedy Orobanchaceae spp. is challenging, particularly due to the highly coordinated life cycles of the parasite and host plants. Although host genetic resistance often provides the foundation of plant pathogen management, few genes that confer resistance to root parasites have been identified and incorporated into crop species. Members of the family Orobanchaceae acquire water, nutrients, macromolecules, and oligonucleotides from host plants through haustoria that connect parasite and host plant roots. We are evaluating a resistance strategy based on using interfering RNA (RNAi) that is made in the host but inhibitory in the parasite as a parasite-derived oligonucleotide toxin. Sequences from the cytosolic acetyl-CoA carboxylase (ACCase) gene from Triphysaria versicolor were cloned in hairpin conformation and introduced into Medicago truncatula roots by Agrobacterium rhizogenes transformation. Transgenic roots were recovered for four of five ACCase constructions and infected with T. versicolor against parasitic weeds. In all cases, Triphysaria root viability was reduced up to 80% when parasitizing a host root bearing the hairpin ACCase. Triphysaria root growth was recovered by exogenous application of malonate. Reverse-transcriptase polymerase chain reaction (RT-PCR) showed that ACCase transcript levels were dramatically decreased in Triphysaria spp. parasitizing transgenic Medicago roots. Northern blot analysis identified a 21-nucleotide, ACCase-specific RNA in transgenic M. truncatula and in T. versicolor attached to them. One hairpin ACCase construction was lethal to Medicago spp. unless grown in media supplemented with malonate. Quantitative RT-PCR showed that the Medicago ACCase was inhibited by the Triphysaria ACCase RNAi. This work shows that ACCase is an effective target for inactivation in parasitic plants by trans-specific gene

Meat goat kids finished on alfalfa, red clover or orchardgrass pastures: carcass merit and meat quality.

Science.gov (United States)

Turner, K E; Cassida, K A; Zerby, H N

2014-12-01

This experiment was conducted in 2005-2007 to evaluate carcass and chevon (goat meat) quality parameters when meat-goat kids (n=72) were finished on alfalfa (Medicago sativa L; ALF); red clover (Trifolium pratense L.; RCG); or orchardgrass (Dactylis glomerata L.; OGR) pastures. Carcass conformation score was greater (P=0.08) when meat-goat kids were finished on ALF compared to OGR with RCG intermediate. Chevon meat samples from goats finished on the three pasture treatments did not differ in ash, intramuscular fat, or crude protein content or in concentrations of omega6 and omega3 fatty acids, or the omega6 to omega3 ratio. Goats finished on OGR had higher (Pmeat-goat kids finished on ALF, RCG, or ORG produced desirable carcass weights for most niche markets in the USA. Chevon is a low-fat meat option with high desirable fatty acids for human diets. Published by Elsevier Ltd.

Rehabilitation materials from surface- coal mines in western U.S.A. III. Relations between elements in mine soil and uptake by plants.

Science.gov (United States)

Severson, R.C.; Gough, L.P.

1984-01-01

Plant uptake of Cd, Co, Cu, Fe, Mn, Ni, Pb and Zn from mine soils was assessed using alfalfa Medicago sativa, sainfoin Onobrychis viciaefolia, smooth brome Bromus inermis, crested wheatgrass Agropyron cristatum, slender wheatgrass A. trachycaulum and intermediate wheatgrass A. intermedium; mine soil (cover-soil and spoil material) samples were collected from rehabilitated areas of 11 western US surface-coal mines in North Dakota, Montana, Wyoming and Colorado. Correlations between metals in plants and DTPA-extractable metals from mine soils were generally not statistically significant and showed no consistent patterns for a single metal or for a single plant species. Metal uptake by plants, relative to amounts in DTPA extracts of mine soil, was positively related to mine soil organic matter content or negatively related to mine soil pH. DTPA-extractable metal levels were significantly correlated with mine soil pH and organic-matter content.-from Authors

Flavonoids released naturally from alfalfa promote development of symbiotic glomus spores in vitro.

Science.gov (United States)

Tsai, S M; Phillips, D A

1991-05-01

Because flavonoids from legumes induce transcription of nodulation genes in symbiotic rhizobial bacteria, it is reasonable to test whether these compounds alter the development of vesicular-arbuscular mycorrhizal (VAM) fungi that infect those plants. Quercetin-3-O-galactoside, the dominant flavonoid released naturally from alfalfa (Medicago sativa L.) seeds, promoted spore germination of Glomus etunicatum and Glomus macrocarpum in vitro. Quercetin produced the maximum increases in spore germination, hyphal elongation, and hyphal branching in G. etunicatum at 1 to 2.5 muM concentrations. Two flavonoids exuded from alfalfa roots, 4',7-dihydroxyflavone and 4',7-dihydroxyflavanone, also enhanced spore germination of this fungal species. Formononetin, an isoflavone that is released from stressed alfalfa roots, inhibited germination of both Glomus species. These in vitro results suggest that plant flavonoids may facilitate or regulate the development of VAM symbioses and offer new hope for developing pure, plant-free cultures of VAM fungi.

Multiple centroid method to evaluate the adaptability of alfalfa genotypes

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Moysés Nascimento

2015-02-01

Full Text Available This study aimed to evaluate the efficiency of multiple centroids to study the adaptability of alfalfa genotypes (Medicago sativa L.. In this method, the genotypes are compared with ideotypes defined by the bissegmented regression model, according to the researcher's interest. Thus, genotype classification is carried out as determined by the objective of the researcher and the proposed recommendation strategy. Despite the great potential of the method, it needs to be evaluated under the biological context (with real data. In this context, we used data on the evaluation of dry matter production of 92 alfalfa cultivars, with 20 cuttings, from an experiment in randomized blocks with two repetitions carried out from November 2004 to June 2006. The multiple centroid method proved efficient for classifying alfalfa genotypes. Moreover, it showed no unambiguous indications and provided that ideotypes were defined according to the researcher's interest, facilitating data interpretation.

Effects of glucogenic and ketogenic feeding strategies on splanchnic glucose and amino acid metabolism in postpartum transition Holstein cows

DEFF Research Database (Denmark)

Larsen, Mogens; Kristensen, Niels Bastian

2012-01-01

assigned to 1 of 3 feeding strategies: a glucogenic diet (GLCG) based on sodium hydroxide treated wheat grain (56.5% of diet dry matter); a ketogenic diet (KETO) based on fodder beets (40.5% of diet dry matter); or an alfalfa-glucogenic strategy (ALF-GLCG) supplying 100% alfalfa (Medicago sativa L......Nine periparturient Holstein cows catheterized in major splanchnic vessels were used in a complete randomized design with repeated measurements to investigate effects of glucogenic and ketogenic feeding strategies on splanchnic metabolism of glucose and amino acids. At parturition, cows were.......) haylage at the day of parturition, followed by a 6-d linear shift to the GLCG diet. Samples were obtained 14 d before expected parturition as well as at 4, 15, and 29 d in milk (DIM). The net portal release of glucose was greatest with GLCG, reflecting the higher intake of ruminal escape starch with GLCG...

Mineral elements of some green vegetables

International Nuclear Information System (INIS)

Khan, A.S.; Tabassum, R.; Yousaf, M.

1998-01-01

Some of the mineral components of Allium porrum Linn, Brassica rapa and Medicago denticulata were studied. Extraction of minerals was carried out in three different ways (I) Ash solution was prepared and used for the determination of Na, K, Ca, P, Fe and Mg. (II) Perchloric acid extraction was employed for Na, K, Fe, Mg, Cu and Zinc. (III) Solvent extraction was used for Na and K. Determination of calcium was done titrimetrically, Na and K. Flame photometrically, P, Fe and Mg Spectrophotometrically, Cu and Zinc Atomic Absorption Spectrophotometrically. Allium porrum Linn was rich in Ca, K and Zinc, in Brassica rapa Fe, Mg and Na in Medicago denticalata P contents were greater. (author)

Mineral elements of some green vegetables

Energy Technology Data Exchange (ETDEWEB)

Khan, A S; Tabassum, R; Yousaf, M [University of Peshawar (Pakistan). Dept. of Chemistry

1998-07-01

Some of the mineral components of Allium porrum Linn, Brassica rapa and Medicago denticulata were studied. Extraction of minerals was carried out in three different ways (I) Ash solution was prepared and used for the determination of Na, K, Ca, P, Fe and Mg. (II) Perchloric acid extraction was employed for Na, K, Fe, Mg, Cu and Zinc. (III) Solvent extraction was used for Na and K. Determination of calcium was done titrimetrically, Na and K. Flame photometrically, P, Fe and Mg Spectrophotometrically, Cu and Zinc Atomic Absorption Spectrophotometrically. Allium porrum Linn was rich in Ca, K and Zinc, in Brassica rapa Fe, Mg and Na in Medicago denticalata P contents were greater. (author)

Plant physiology and proteomics reveals the leaf response to drought in alfalfa (Medicago sativa L.).

Science.gov (United States)

Aranjuelo, Iker; Molero, Gemma; Erice, Gorka; Avice, Jean Christophe; Nogués, Salvador

2011-01-01

Despite its relevance, protein regulation, metabolic adjustment, and the physiological status of plants under drought is not well understood in relation to the role of nitrogen fixation in nodules. In this study, nodulated alfalfa plants were exposed to drought conditions. The study determined the physiological, metabolic, and proteomic processes involved in photosynthetic inhibition in relation to the decrease in nitrogenase (N(ase)) activity. The deleterious effect of drought on alfalfa performance was targeted towards photosynthesis and N(ase) activity. At the leaf level, photosynthetic inhibition was mainly caused by the inhibition of Rubisco. The proteomic profile and physiological measurements revealed that the reduced carboxylation capacity of droughted plants was related to limitations in Rubisco protein content, activation state, and RuBP regeneration. Drought also decreased amino acid content such as asparagine, and glutamic acid, and Rubisco protein content indicating that N availability limitations were caused by N(ase) activity inhibition. In this context, drought induced the decrease in Rubisco binding protein content at the leaf level and proteases were up-regulated so as to degrade Rubisco protein. This degradation enabled the reallocation of the Rubisco-derived N to the synthesis of amino acids with osmoregulant capacity. Rubisco degradation under drought conditions was induced so as to remobilize Rubisco-derived N to compensate for the decrease in N associated with N(ase) inhibition. Metabolic analyses showed that droughted plants increased amino acid (proline, a major compound involved in osmotic regulation) and soluble sugar (D-pinitol) levels to contribute towards the decrease in osmotic potential (Ψ(s)). At the nodule level, drought had an inhibitory effect on N(ase) activity. This decrease in N(ase) activity was not induced by substrate shortage, as reflected by an increase in total soluble sugars (TSS) in the nodules. Proline accumulation in the nodule could also be associated with an osmoregulatory response to drought and might function as a protective agent against ROS. In droughted nodules, the decrease in N(2) fixation was caused by an increase in oxygen resistance that was induced in the nodule. This was a mechanism to avoid oxidative damage associated with reduced respiration activity and the consequent increase in oxygen content. This study highlighted that even though drought had a direct effect on leaves, the deleterious effects of drought on nodules also conditioned leaf responsiveness.

Combining -Omics to Unravel the Impact of Copper Nutrition on Alfalfa (Medicago sativa) Stem Metabolism.

Science.gov (United States)

Printz, Bruno; Guerriero, Gea; Sergeant, Kjell; Audinot, Jean-Nicolas; Guignard, Cédric; Renaut, Jenny; Lutts, Stanley; Hausman, Jean-Francois

2016-02-01

Copper can be found in the environment at concentrations ranging from a shortage up to the threshold of toxicity for plants, with optimal growth conditions situated in between. The plant stem plays a central role in transferring and distributing minerals, water and other solutes throughout the plant. In this study, alfalfa is exposed to different levels of copper availability, from deficiency to slight excess, and the impact on the metabolism of the stem is assessed by a non-targeted proteomics study and by the expression analysis of key genes controlling plant stem development. Under copper deficiency, the plant stem accumulates specific copper chaperones, the expression of genes involved in stem development is decreased and the concentrations of zinc and molybdenum are increased in comparison with the optimum copper level. At the optimal copper level, the expression of cell wall-related genes increases and proteins playing a role in cell wall deposition and in methionine metabolism accumulate, whereas copper excess imposes a reduction in the concentration of iron in the stem and a reduced abundance of ferritins. Secondary ion mass spectrometry (SIMS) analysis suggests a role for the apoplasm as a copper storage site in the case of copper toxicity. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists.