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Sample records for mesorhizobium mediterraneum mesorhizobium

  1. Activity of the Recommended and Optimized Rates of Pyridate on Chickpea - Mesorhizobium mediterraneum Symbiosis

    Mehdi PARSA

    2014-03-01

    Full Text Available Crop-rhizobium symbiosis can be influenced by leaching of herbicides which is unavoidable after their application. Due to an adjuvant which might help to develop the low-use-rate of herbicide, an experiment was carried out to compare the impact of the recommended rate (1200 g active ingredient ha-1 and the optimized rate (282.15 g active ingredient ha-1 of pyridate on the biological properties of eight chickpea cultivars inoculated with Mesorhizobium mediterraneum, grown in pots. Based on the required rate of herbicide to give 95% control of common lambsquarters (Chenopodium album L. value, the efficacy of pyridate improved up to 3.87-fold by adding methylated rapeseed oil to spray solution. The ‘Desi’ cultivar had significantly higher nodulation than ‘Kabuli’ cultivar. In general, toxicity of the recommended rate was higher than the optimized rate. With the exception of root dry weight, all of the measured parameters were significantly affected by the recommended rate of pyridate in varying degrees. The symbiotic properties of chickpea cultivars were affected more than 10% at the recommended dose. The reduced nodulation ranged from 29% to 73% among cultivars exposed to pyridate at the recommended dose. The ‘Desi’ cultivar was more sensitive than the ‘Kabuli’ to the recommended rate of pyridate. We may conclude that effective low-use-rate of pyridate via applying of activator adjuvants should be noted.

  2. Mesorhizobium shonense sp. nov., Mesorhizobium hawassense sp. nov. and Mesorhizobium abyssinicae sp. nov., isolated from root nodules of different agroforestry legume trees.

    Degefu, Tulu; Wolde-Meskel, Endalkachew; Liu, Binbin; Cleenwerck, Ilse; Willems, Anne; Frostegård, Åsa

    2013-05-01

    A total of 18 strains, representing members of the genus Mesorhizobium, obtained from root nodules of woody legumes growing in Ethiopia, have been previously shown, by multilocus sequence analysis (MLSA) of five housekeeping genes, to form three novel genospecies. In the present study, the phylogenetic relationship between representative strains of these three genospecies and the type strains of their closest phylogenetic neighbours Mesorhizobium plurifarium, Mesorhizobium amorphae, Mesorhizobium septentrionale and Mesorhizobium huakuii was further evaluated using a polyphasic taxonomic approach. In line with our earlier MLSA of other housekeeping genes, the phylogenetic trees derived from the atpD and glnII genes grouped the test strains into three well-supported, distinct lineages that exclude all defined species of the genus Mesorhizobium. The DNA-DNA relatedness between the representative strains of genospecies I-III and the type strains of their closest phylogenetic neighbours was low (≤59 %). They differed from each other and from their closest phylogenetic neighbours by the presence/absence of several fatty acids, or by large differences in the relative amounts of particular fatty acids. While showing distinctive features, they were generally able to utilize a wide range of substrates as sole carbon and nitrogen sources. The strains belonging to genospecies I, II and III therefore represent novel species for which we propose the names Mesorhizobium shonense sp. nov., Mesorhizobium hawassense sp. nov. and Mesorhizobium abyssinicae sp. nov. The isolates AC39a(T) ( = LMG 26966(T) = HAMBI 3295(T)), AC99b(T) ( = LMG 26968(T) = HAMBI 3301(T)) and AC98c(T) ( = LMG 26967(T) = HAMBI 3306(T)) are proposed as type strains for the respective novel species.

  3. Structure of Mesorhizobium loti arylamine N-acetyltransferase 1

    Holton, Simon J. [Laboratory of Molecular Biophysics, Department of Biochemistry, Oxford University, South Parks Road, Oxford OX1 3QU (United Kingdom); Dairou, Julien [CNRS-UMR 7000, Faculté de Médecine Pitié-Salpêtrière, 105 Boulevard de l’Hôpital, 75013 Paris (France); Sandy, James [Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT (United Kingdom); Rodrigues-Lima, Fernando; Dupret, Jean-Marie [CNRS-UMR 7000, Faculté de Médecine Pitié-Salpêtrière, 105 Boulevard de l’Hôpital, 75013 Paris (France); UFR de Biochimie, Université Denis Diderot-Paris 7, 75005 Paris (France); Noble, Martin E. M. [Laboratory of Molecular Biophysics, Department of Biochemistry, Oxford University, South Parks Road, Oxford OX1 3QU (United Kingdom); Sim, Edith, E-mail: edith.sim@pharm.ox.ac.uk [Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT (United Kingdom); Laboratory of Molecular Biophysics, Department of Biochemistry, Oxford University, South Parks Road, Oxford OX1 3QU (United Kingdom)

    2005-01-01

    The crystal structure of a M. loti arylamine N-acetyltransferase 1 has been determined at 2.0 Å resolution. The arylamine N-acetyltransferase (NAT) enzymes have been found in a broad range of both eukaryotic and prokaryotic organisms. The NAT enzymes catalyse the transfer of an acetyl group from acetyl Co-enzyme A onto the terminal nitrogen of a range of arylamine, hydrazine and arylhydrazine compounds. Recently, several NAT structures have been reported from different prokaryotic sources including Salmonella typhimurium, Mycobacterium smegmatis and Pseudomonas aeruginosa. Bioinformatics analysis of the Mesorhizobium loti genome revealed two NAT paralogues, the first example of multiple NAT isoenzymes in a eubacterial organism. The M. loti NAT 1 enzyme was recombinantly expressed and purified for X-ray crystallographic studies. The purified enzyme was crystallized in 0.5 M Ca(OAc){sub 2}, 16% PEG 3350, 0.1 M Tris–HCl pH 8.5 using the sitting-drop vapour-diffusion method. A data set diffracting to 2.0 Å was collected from a single crystal at 100 K. The crystal belongs to the orthorhombic spacegroup P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 53.2, b = 97.3, c = 114.3 Å. The structure was refined to a final free-R factor of 24.8%. The structure reveals that despite low sequence homology, M. loti NAT1 shares the common fold as reported in previous NAT structures and exhibits the same catalytic triad of residues (Cys-His-Asp) in the active site.

  4. Structure of Mesorhizobium loti arylamine N-acetyltransferase 1

    Holton, Simon J.; Dairou, Julien; Sandy, James; Rodrigues-Lima, Fernando; Dupret, Jean-Marie; Noble, Martin E. M.; Sim, Edith

    2004-01-01

    The crystal structure of a M. loti arylamine N-acetyltransferase 1 has been determined at 2.0 Å resolution. The arylamine N-acetyltransferase (NAT) enzymes have been found in a broad range of both eukaryotic and prokaryotic organisms. The NAT enzymes catalyse the transfer of an acetyl group from acetyl Co-enzyme A onto the terminal nitrogen of a range of arylamine, hydrazine and arylhydrazine compounds. Recently, several NAT structures have been reported from different prokaryotic sources including Salmonella typhimurium, Mycobacterium smegmatis and Pseudomonas aeruginosa. Bioinformatics analysis of the Mesorhizobium loti genome revealed two NAT paralogues, the first example of multiple NAT isoenzymes in a eubacterial organism. The M. loti NAT 1 enzyme was recombinantly expressed and purified for X-ray crystallographic studies. The purified enzyme was crystallized in 0.5 M Ca(OAc) 2 , 16% PEG 3350, 0.1 M Tris–HCl pH 8.5 using the sitting-drop vapour-diffusion method. A data set diffracting to 2.0 Å was collected from a single crystal at 100 K. The crystal belongs to the orthorhombic spacegroup P2 1 2 1 2 1 , with unit-cell parameters a = 53.2, b = 97.3, c = 114.3 Å. The structure was refined to a final free-R factor of 24.8%. The structure reveals that despite low sequence homology, M. loti NAT1 shares the common fold as reported in previous NAT structures and exhibits the same catalytic triad of residues (Cys-His-Asp) in the active site

  5. Removal of zinc from aqueous solution by metal resistant symbiotic bacterium Mesorhizobium amorphae

    Hao, Xiuli; Mohamad, Osama Abdalla; Xie, Pin

    2014-01-01

    Biosorption of zinc by living biomasses of metal resistant symbiotic bacterium Mesorhizobium amorphae CCNWGS0123 was investigated under optimal conditions at pH 5.0, initial metal concentrations of 100 mg L-1, and a dose of 1.0 g L-1. M. amorphae exhibited an efficient removal of Zn2+ from aqueous...

  6. Chemical characterization of the gels produced by the diazotrophic bacteria Rhizobium tropici and Mesorhizobium sp; Caracterizacao quimica dos geis produzidos pelas bacterias diazotroficas Rhizobium tropici e Mesorhizobium sp.

    Monteiro, Nilson Kobori [Departamento de Engenharia e Tecnologia de Alimentos, Instituto de Biociencias, Letras e Ciencias Exatas, Universidade Estadual Paulista, Sao Jose do Rio Preto - SP (Brazil); Aranda-Selverio, Gabriel; Exposti, Diego Tadeu Degli; Silva, Maria de Lourdes Corradi da [Departamento de Fisica, Quimica e Biologia, Faculdade de Ciencias e Tecnologia, Universidade Estadual Paulista, Presidente Prudente - SP (Brazil); Lemos, Eliana Gertrudes Macedo; Campanharo, Joao Carlos [Departamento de Tecnologia, Faculdade de Ciencias Agrarias e Veterinaria, Universidade Estadual Paulista, Jaboticabal - SP (Brazil); Silveira, Joana Lea Meira [Departamento de Bioquimica e Biologia Molecular, Universidade Federal do Parana, Curitiba - PR (Brazil)

    2012-07-01

    The exopolysaccharides with characteristics of gel produced by Rhizobium tropici (EPSRT) and Mesorhizobium sp (EPSMR) are acidic heteropolysaccharide composed mainly of glucose and galactose in a molar ratio of 4:1 and 5:1 respectively, with traces of mannose ({approx} 1%). Chemical analysis showed the presence of uronic acid, pyruvate and acetyl-substituents in the structures of both polymers. Experiments of gel permeation chromatography and polyacrylamide gel electrophoresis showed that EPSRT and EPSMR are homogeneous molecules with low grade of polydispersity. The EPS were characterized using spectroscopic techniques of FT-IR, {sup 1}H and {sup 13}C-NMR. (author)

  7. Comparative transcriptome analysis of nodules of two Mesorhizobium-chickpea associations with differential symbiotic efficiency under phosphate deficiency.

    Nasr Esfahani, Maryam; Inoue, Komaki; Chu, Ha Duc; Nguyen, Kien Huu; Van Ha, Chien; Watanabe, Yasuko; Burritt, David J; Herrera-Estrella, Luis; Mochida, Keiichi; Tran, Lam-Son Phan

    2017-09-01

    Phosphate (Pi) deficiency is known to be a major limitation for symbiotic nitrogen fixation (SNF), and hence legume crop productivity globally. However, very little information is available on the adaptive mechanisms, particularly in the important legume crop chickpea (Cicer arietinum L.), which enable nodules to respond to low-Pi availability. Thus, to elucidate these mechanisms in chickpea nodules at molecular level, we used an RNA sequencing approach to investigate transcriptomes of the nodules in Mesorhizobium mediterraneum SWRI9-(MmSWRI9)-chickpea and M. ciceri CP-31-(McCP-31)-chickpea associations under Pi-sufficient and Pi-deficient conditions, of which the McCP-31-chickpea association has a better SNF capacity than the MmSWRI9-chickpea association during Pi starvation. Our investigation revealed that more genes showed altered expression patterns in MmSWRI9-induced nodules than in McCP-31-induced nodules (540 vs. 225) under Pi deficiency, suggesting that the Pi-starvation-more-sensitive MmSWRI9-induced nodules required expression change in a larger number of genes to cope with low-Pi stress than the Pi-starvation-less-sensitive McCP-31-induced nodules. The functional classification of differentially expressed genes (DEGs) was examined to gain an understanding of how chickpea nodules respond to Pi starvation, caused by soil Pi deficiency. As a result, more DEGs involved in nodulation, detoxification, nutrient/ion transport, transcriptional factors, key metabolic pathways, Pi remobilization and signalling were found in Pi-starved MmSWRI9-induced nodules than in Pi-starved McCP-31-induced nodules. Our findings have enabled the identification of molecular processes that play important roles in the acclimation of nodules to Pi deficiency, ultimately leading to the development of Pi-efficient chickpea symbiotic associations suitable for Pi-deficient soils. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

  8. Chemical characterization of the gels produced by the diazotrophic bacteria Rhizobium tropici and Mesorhizobium sp

    Monteiro, Nilson Kobori; Aranda-Selverio, Gabriel; Exposti, Diego Tadeu Degli; Silva, Maria de Lourdes Corradi da; Lemos, Eliana Gertrudes Macedo; Campanharo, Joao Carlos; Silveira, Joana Lea Meira

    2012-01-01

    The exopolysaccharides with characteristics of gel produced by Rhizobium tropici (EPSRT) and Mesorhizobium sp (EPSMR) are acidic heteropolysaccharide composed mainly of glucose and galactose in a molar ratio of 4:1 and 5:1 respectively, with traces of mannose (∼ 1%). Chemical analysis showed the presence of uronic acid, pyruvate and acetyl-substituents in the structures of both polymers. Experiments of gel permeation chromatography and polyacrylamide gel electrophoresis showed that EPSRT and EPSMR are homogeneous molecules with low grade of polydispersity. The EPS were characterized using spectroscopic techniques of FT-IR, 1 H and 13 C-NMR. (author)

  9. Synergistic effect of chickpea plants and Mesorhizobium as a natural system for chromium phytoremediation.

    Velez, Pilar A; Talano, Melina A; Paisio, Cintia E; Agostini, Elizabeth; González, Paola S

    2017-09-01

    The presence of chromium in soils not only affects the physiological processes of plants but also the microbial rhizosphere composition and metabolic activities of microorganisms. Hence, the inoculation of plants with Cr(VI)-tolerant rhizospheric microorganisms as an alternative to reduce Cr phytotoxicity was studied. In this work, chickpea germination was reduced by Cr(VI) concentrations of 150 and 250 mg/L (6 and 33%, respectively); however lower Cr(VI) concentrations negatively affected the biomass. On the other hand, its symbiont, Mesorhizobium ciceri, was able to grow and remove different Cr(VI) concentrations (5-20 mg/L). The inoculation of chickpea plants with this strain exposed to Cr(VI) showed a significantly enhanced plant growth. In addition, inoculated plants accumulated higher Cr concentration in roots than those noninoculated. It is important to note that Cr was not translocated to shoots independently of inoculation. These results suggest that Mesorhizobium's capability to remove Cr(VI) could be exploited for bioremediation. Moreover, chickpea plants would represent a natural system for phytoremediation or phytostabilization of Cr in situ that could be improved with M. ciceri inoculation. This strategy would be considered as a phytoremediation tool with great economic and ecological relevance.

  10. Diverse Mesorhizobium bacteria nodulate native Astragalus and Oxytropis in arctic and subarctic areas in Eurasia.

    Ampomah, Osei Yaw; Mousavi, Seyed Abdollah; Lindström, Kristina; Huss-Danell, Kerstin

    2017-01-01

    Rhizobia nodulating native Astragalus and Oxytropis spp. in Northern Europe are not well-studied. In this study, we isolated bacteria from nodules of four Astragalus spp. and two Oxytropis spp. from the arctic and subarctic regions of Sweden and Russia. The phylogenetic analyses were performed by using sequences of three housekeeping genes (16S rRNA, rpoB and recA) and two accessory genes (nodC and nifH). The results of our multilocus sequence analysis (MLSA) of the three housekeeping genes tree showed that all the 13 isolates belonged to the genus Mesorhizobium and were positioned in six clades. Our concatenated housekeeping gene tree also suggested that the isolates nodulating Astragalus inopinatus, Astragalus frigidus, Astragalus alpinus ssp. alpinus and Oxytropis revoluta might be designated as four new Mesorhizobium species. The 13 isolates were grouped in three clades in the nodC and nifH trees. 15 N analysis suggested that the legumes in association with these isolates were actively fixing nitrogen. Copyright © 2016 Elsevier GmbH. All rights reserved.

  11. Quorum Sensing Activity of Mesorhizobium sp. F7 Isolated from Potable Water

    Pei-Ling Yong

    2014-01-01

    Full Text Available We isolated a bacterial isolate (F7 from potable water. The strain was identified as Mesorhizobium sp. by 16S rDNA gene phylogenetic analysis and screened for N-acyl homoserine lactone (AHL production by an AHL biosensor. The AHL profile of the isolate was further analyzed using high resolution triple quadrupole liquid chromatography mass spectrometry (LC/MS which confirmed the production of multiple AHLs, namely, N-3-oxo-octanoyl-L-homoserine lactone (3-oxo-C8-HSL and N-3-oxo-decanoyl-L-homoserine lactone (3-oxo-C10-HSL. These findings will open the perspective to study the function of these AHLs in plant-microbe interactions.

  12. Genome sequence of the Lotus spp. microsymbiont Mesorhizobium loti strain R7A.

    Kelly, Simon; Sullivan, John; Ronson, Clive; Tian, Rui; Bräu, Lambert; Munk, Christine; Goodwin, Lynne; Han, Cliff; Woyke, Tanja; Reddy, Tatiparthi; Huntemann, Marcel; Pati, Amrita; Mavromatis, Konstantinos; Markowitz, Victor; Ivanova, Natalia; Kyrpides, Nikos; Reeve, Wayne

    2014-01-01

    Mesorhizobium loti strain R7A was isolated in 1993 in Lammermoor, Otago, New Zealand from a Lotus corniculatus root nodule and is a reisolate of the inoculant strain ICMP3153 (NZP2238) used at the site. R7A is an aerobic, Gram-negative, non-spore-forming rod. The symbiotic genes in the strain are carried on a 502-kb integrative and conjugative element known as the symbiosis island or ICEMlSym(R7A). M. loti is the microsymbiont of the model legume Lotus japonicus and strain R7A has been used extensively in studies of the plant-microbe interaction. This report reveals that the genome of M. loti strain R7A does not harbor any plasmids and contains a single scaffold of size 6,529,530 bp which encodes 6,323 protein-coding genes and 75 RNA-only encoding genes. This rhizobial genome is one of 100 sequenced as part of the DOE Joint Genome Institute 2010 Genomic Encyclopedia for Bacteria and Archaea-Root Nodule Bacteria (GEBA-RNB) project.

  13. Adaptation of the symbiotic Mesorhizobium-chickpea relationship to phosphate deficiency relies on reprogramming of whole-plant metabolism.

    Nasr Esfahani, Maryam; Kusano, Miyako; Nguyen, Kien Huu; Watanabe, Yasuko; Ha, Chien Van; Saito, Kazuki; Sulieman, Saad; Herrera-Estrella, Luis; Tran, L S

    2016-08-09

    Low inorganic phosphate (Pi) availability is a major constraint for efficient nitrogen fixation in legumes, including chickpea. To elucidate the mechanisms involved in nodule acclimation to low Pi availability, two Mesorhizobium-chickpea associations exhibiting differential symbiotic performances, Mesorhizobium ciceri CP-31 (McCP-31)-chickpea and Mesorhizobium mediterranum SWRI9 (MmSWRI9)-chickpea, were comprehensively studied under both control and low Pi conditions. MmSWRI9-chickpea showed a lower symbiotic efficiency under low Pi availability than McCP-31-chickpea as evidenced by reduced growth parameters and down-regulation of nifD and nifK These differences can be attributed to decline in Pi level in MmSWRI9-induced nodules under low Pi stress, which coincided with up-regulation of several key Pi starvation-responsive genes, and accumulation of asparagine in nodules and the levels of identified amino acids in Pi-deficient leaves of MmSWRI9-inoculated plants exceeding the shoot nitrogen requirement during Pi starvation, indicative of nitrogen feedback inhibition. Conversely, Pi levels increased in nodules of Pi-stressed McCP-31-inoculated plants, because these plants evolved various metabolic and biochemical strategies to maintain nodular Pi homeostasis under Pi deficiency. These adaptations involve the activation of alternative pathways of carbon metabolism, enhanced production and exudation of organic acids from roots into the rhizosphere, and the ability to protect nodule metabolism against Pi deficiency-induced oxidative stress. Collectively, the adaptation of symbiotic efficiency under Pi deficiency resulted from highly coordinated processes with an extensive reprogramming of whole-plant metabolism. The findings of this study will enable us to design effective breeding and genetic engineering strategies to enhance symbiotic efficiency in legume crops.

  14. Characterization of a periplasmic S1-like nuclease coded by the Mesorhizobium loti symbiosis island

    Pimkin, Maxim; Miller, C. Glenn; Blakesley, Lauryn; Oleykowski, Catherine A.; Kodali, Nagendra S.; Yeung, Anthony T.

    2006-01-01

    DNA sequences encoding hypothetical proteins homologous to S1 nuclease from Aspergillus oryzae are found in many organisms including fungi, plants, pathogenic bacteria, and eukaryotic parasites. One of these is the M1 nuclease of Mesorhizobium loti which we demonstrate herein to be an enzymatically active, soluble, and stable S1 homolog that lacks the extensive mannosyl-glycosylation found in eukaryotic S1 nuclease homologs. We have expressed the cloned M1 protein in M. loti and purified recombinant native M1 to near homogeneity and have also isolated a homogeneous M1 carboxy-terminal hexahistidine tag fusion protein. Mass spectrometry and N-terminal Edman degradation sequencing confirmed the protein identity. The enzymatic properties of the purified M1 nuclease are similar to those of S1. At acidic pH M1 is 25 times more active on single-stranded DNA than on double-stranded DNA and 3 times more active on single-stranded DNA than on single-stranded RNA. At neutral pH the RNase activity of M1 exceeds the DNase activity. M1 nicks supercoiled RF-I plasmid DNA and rapidly cuts the phosphodiester bond across from the nick in the resultant relaxed RF-II plasmid DNA. Therefore, M1 represents an active bacterial S1 homolog in spite of great sequence divergence. The biochemical characterization of M1 nuclease supports our sequence alignment that reveals the minimal 21 amino acid residues that are necessarily conserved for the structure and functions of this enzyme family. The ability of M1 to degrade RNA at neutral pH implies previously unappreciated roles of these nucleases in biological systems

  15. Genetic and genomic diversity studies of Acacia symbionts in Senegal reveal new species of Mesorhizobium with a putative geographical pattern.

    Fatou Diouf

    Full Text Available Acacia senegal (L Willd. and Acacia seyal Del. are highly nitrogen-fixing and moderately salt tolerant species. In this study we focused on the genetic and genomic diversity of Acacia mesorhizobia symbionts from diverse origins in Senegal and investigated possible correlations between the genetic diversity of the strains, their soil of origin, and their tolerance to salinity. We first performed a multi-locus sequence analysis on five markers gene fragments on a collection of 47 mesorhizobia strains of A. senegal and A. seyal from 8 localities. Most of the strains (60% clustered with the M. plurifarium type strain ORS 1032T, while the others form four new clades (MSP1 to MSP4. We sequenced and assembled seven draft genomes: four in the M. plurifarium clade (ORS3356, ORS3365, STM8773 and ORS1032T, one in MSP1 (STM8789, MSP2 (ORS3359 and MSP3 (ORS3324. The average nucleotide identities between these genomes together with the MLSA analysis reveal three new species of Mesorhizobium. A great variability of salt tolerance was found among the strains with a lack of correlation between the genetic diversity of mesorhizobia, their salt tolerance and the soils samples characteristics. A putative geographical pattern of A. senegal symbionts between the dryland north part and the center of Senegal was found, reflecting adaptations to specific local conditions such as the water regime. However, the presence of salt does not seem to be an important structuring factor of Mesorhizobium species.

  16. Genetic and genomic diversity studies of Acacia symbionts in Senegal reveal new species of Mesorhizobium with a putative geographical pattern.

    Diouf, Fatou; Diouf, Diegane; Klonowska, Agnieszka; Le Queré, Antoine; Bakhoum, Niokhor; Fall, Dioumacor; Neyra, Marc; Parrinello, Hugues; Diouf, Mayecor; Ndoye, Ibrahima; Moulin, Lionel

    2015-01-01

    Acacia senegal (L) Willd. and Acacia seyal Del. are highly nitrogen-fixing and moderately salt tolerant species. In this study we focused on the genetic and genomic diversity of Acacia mesorhizobia symbionts from diverse origins in Senegal and investigated possible correlations between the genetic diversity of the strains, their soil of origin, and their tolerance to salinity. We first performed a multi-locus sequence analysis on five markers gene fragments on a collection of 47 mesorhizobia strains of A. senegal and A. seyal from 8 localities. Most of the strains (60%) clustered with the M. plurifarium type strain ORS 1032T, while the others form four new clades (MSP1 to MSP4). We sequenced and assembled seven draft genomes: four in the M. plurifarium clade (ORS3356, ORS3365, STM8773 and ORS1032T), one in MSP1 (STM8789), MSP2 (ORS3359) and MSP3 (ORS3324). The average nucleotide identities between these genomes together with the MLSA analysis reveal three new species of Mesorhizobium. A great variability of salt tolerance was found among the strains with a lack of correlation between the genetic diversity of mesorhizobia, their salt tolerance and the soils samples characteristics. A putative geographical pattern of A. senegal symbionts between the dryland north part and the center of Senegal was found, reflecting adaptations to specific local conditions such as the water regime. However, the presence of salt does not seem to be an important structuring factor of Mesorhizobium species.

  17. Crystallization and preliminary X-ray crystallographic studies of β-transaminase from Mesorhizobium sp. strain LUK

    Kim, Bokyung; Park, Ok Kyeung; Bae, Ju Young; Jang, Tae-ho; Yoon, Jong Hwan; Do, Kyoung Hun; Kim, Byung-Gee; Yun, Hyungdon; Park, Hyun Ho

    2011-01-01

    β-Transaminase from Mesorhizobium sp. strain LUK was crystallized. The crystals were found to belong to the orthorhombic space group C222 1 , with unit-cell parameters a = 90.91, b = 192.17, c = 52.75 Å. The crystals were obtained at 293 K and diffracted to a resolution of 2.5 Å. β-Transaminase (β-TA) catalyzes the transamination reaction between β-aminocarboxylic acids and keto acids. This enzyme is a particularly suitable candidate for use as a biocatalyst for the asymmetric synthesis of enantiochemically pure β-amino acids for pharmaceutical purposes. The β-TA from Mesorhizobium sp. strain LUK (β-TAMs) belongs to a novel class in that it shows β-transaminase activity with a broad and unique substrate specificity. In this study, β-TAMs was overexpressed in Escherichia coli with an engineered C-terminal His tag. β-TAMs was then purified to homogeneity and crystallized at 293 K. X-ray diffraction data were collected to a resolution of 2.5 Å from a crystal that belonged to the orthorhombic space group C222 1 , with unit-cell parameters a = 90.91, b = 192.17, c = 52.75 Å

  18. [Cloning, mutagenesis and symbiotic phenotype of three lipid transfer protein encoding genes from Mesorhizobium huakuii 7653R].

    Li, Yanan; Zeng, Xiaobo; Zhou, Xuejuan; Li, Youguo

    2016-12-04

    Lipid transfer protein superfamily is involved in lipid transport and metabolism. This study aimed to construct mutants of three lipid transfer protein encoding genes in Mesorhizobium huakuii 7653R, and to study the phenotypes and function of mutations during symbiosis with Astragalus sinicus. We used bioinformatics to predict structure characteristics and biological functions of lipid transfer proteins, and conducted semi-quantitative and fluorescent quantitative real-time PCR to analyze the expression levels of target genes in free-living and symbiotic conditions. Using pK19mob insertion mutagenesis to construct mutants, we carried out pot plant experiments to observe symbiotic phenotypes. MCHK-5577, MCHK-2172 and MCHK-2779 genes encoding proteins belonged to START/RHO alpha_C/PITP/Bet_v1/CoxG/CalC (SRPBCC) superfamily, involved in lipid transport or metabolism, and were identical to M. loti at 95% level. Gene relative transcription level of the three genes all increased compared to free-living condition. We obtained three mutants. Compared with wild-type 7653R, above-ground biomass of plants and nodulenitrogenase activity induced by the three mutants significantly decreased. Results indicated that lipid transfer protein encoding genes of Mesorhizobium huakuii 7653R may play important roles in symbiotic nitrogen fixation, and the mutations significantly affected the symbiotic phenotypes. The present work provided a basis to study further symbiotic function mechanism associated with lipid transfer proteins from rhizobia.

  19. The trehalose utilization gene thuA ortholog in Mesorhizobium loti does not influence competitiveness for nodulation on Lotus spp.

    Ampomah, Osei Yaw; Jensen, John Beck

    2014-03-01

    Competitiveness for nodulation is a desirable trait in rhizobia strains used as inoculant. In Sinorhizobium meliloti 1021 mutation in either of the trehalose utilization genes thuA or thuB influences its competitiveness for root colonization and nodule occupancy depending on the interacting host. We have therefore investigated whether mutation in the thuA ortholog in Mesorhizobium loti MAFF303099 also leads to a similar competitive phenotype on its hosts. The results show that M. loti thuA mutant Ml7023 was symbiotically effective and was as competitive as the wild type in colonization and nodule occupancy on Lotus corniculatus and Lotus japonicus. The thuA gene in M. loti was not induced during root colonization or in the infection threads unlike in S. meliloti, despite its induction by trehalose and high osmolarity in in vitro assays.

  20. Development of Mesorhizobium ciceri-Based Biofilms and Analyses of Their Antifungal and Plant Growth Promoting Activity in Chickpea Challenged by Fusarium Wilt.

    Das, Krishnashis; Rajawat, Mahendra Vikram Singh; Saxena, Anil Kumar; Prasanna, Radha

    2017-03-01

    Biofilmed biofertilizers have emerged as a new improved inoculant technology to provide efficient nutrient and pest management and sustain soil fertility. In this investigation, development of a Trichoderma viride - Mesorhizobium ciceri biofilmed inoculant was undertaken, which we hypothesized, would possess more effective biological nitrogen fixing ability and plant growth promoting properties. As a novel attempt, we selected Mesorhizobium ciceri spp. with good antifungal attributes with the assumption that such inoculants could also serve as biocontrol agents. These biofilms exhibited significant enhancement in several plant growth promoting attributes, including 13-21 % increase in seed germination, production of ammonia, IAA and more than onefold to twofold enhancement in phosphate solubilisation, when compared to their individual partners. Enhancement of 10-11 % in antifungal activity against Fusarium oxysporum f. sp. ciceri was also recorded, over the respective M. ciceri counterparts. The effect of biofilms and the M. ciceri cultures individual on growth parameters of chickpea under pathogen challenged soil illustrated that the biofilms performed at par with the M. ciceri strains for most plant biometrical and disease related attributes. Elicitation of defense related enzymes like l-phenylalanine ammonia lyase, peroxidase and polyphenol oxidase was higher in M. ciceri /biofilm treated plants as compared to uninoculated plants under pathogen challenged soil. Further work on the signalling mechanisms among the partners and their tripartite interactions with host plant is envisaged in future studies.

  1. Phylogeny of nodulation genes and symbiotic diversity of Acacia senegal (L.) Willd. and A. seyal (Del.) Mesorhizobium strains from different regions of Senegal.

    Bakhoum, Niokhor; Galiana, Antoine; Le Roux, Christine; Kane, Aboubacry; Duponnois, Robin; Ndoye, Fatou; Fall, Dioumacor; Noba, Kandioura; Sylla, Samba Ndao; Diouf, Diégane

    2015-04-01

    Acacia senegal and Acacia seyal are small, deciduous legume trees, most highly valued for nitrogen fixation and for the production of gum arabic, a commodity of international trade since ancient times. Symbiotic nitrogen fixation by legumes represents the main natural input of atmospheric N2 into ecosystems which may ultimately benefit all organisms. We analyzed the nod and nif symbiotic genes and symbiotic properties of root-nodulating bacteria isolated from A. senegal and A. seyal in Senegal. The symbiotic genes of rhizobial strains from the two Acacia species were closed to those of Mesorhizobium plurifarium and grouped separately in the phylogenetic trees. Phylogeny of rhizobial nitrogen fixation gene nifH was similar to those of nodulation genes (nodA and nodC). All A. senegal rhizobial strains showed identical nodA, nodC, and nifH gene sequences. By contrast, A. seyal rhizobial strains exhibited different symbiotic gene sequences. Efficiency tests demonstrated that inoculation of both Acacia species significantly affected nodulation, total dry weight, acetylene reduction activity (ARA), and specific acetylene reduction activity (SARA) of plants. However, these cross-inoculation tests did not show any specificity of Mesorhizobium strains toward a given Acacia host species in terms of infectivity and efficiency as stated by principal component analysis (PCA). This study demonstrates that large-scale inoculation of A. senegal and A. seyal in the framework of reafforestation programs requires a preliminary step of rhizobial strain selection for both Acacia species.

  2. Mesorhizobium bacterial strains isolated from the legume Lotus corniculatus are an alternative source for the production of polyhydroxyalkanoates (PHAs) to obtain bioplastics.

    Marcos-García, Marta; García-Fraile, Paula; Filipová, Alena; Menéndez, Esther; Mateos, Pedro F; Velázquez, Encarna; Cajthaml, Tomáš; Rivas, Raúl

    2017-07-01

    Polyhydroxyalkanoic acids (PHAs) are natural polyesters that can be used to produce bioplastics which are biodegradable. Numerous microorganisms accumulate PHAs as energy reserves. Combinations of different PHAs monomers lead to the production of bioplastics with very different properties. In the present work, we show the capability of strains belonging to various phylogenetic lineages within the genus Mesorhizobium, isolated from Lotus corniculatus nodules, to produce different PHA monomers. Among our strains, we found the production of 3-hydroxybutyrate, 3-hydroxyvalerate, 3-hydroxydodecanoate, and 3-hydroxyhexadecanoate. Most of the PHA-positive strains were phylogenetically related to the species M. jarvisii. However, our findings suggest that the ability to produce different monomers forming PHAs is strain-dependent.

  3. Core and symbiotic genes reveal nine Mesorhizobium genospecies and three symbiotic lineages among the rhizobia nodulating Cicer canariense in its natural habitat (La Palma, Canary Islands).

    Armas-Capote, Natalia; Pérez-Yépez, Juan; Martínez-Hidalgo, Pilar; Garzón-Machado, Víctor; Del Arco-Aguilar, Marcelino; Velázquez, Encarna; León-Barrios, Milagros

    2014-03-01

    Cicer canariense is a threatened perennial wild chickpea endemic to the Canary Islands. In this study, rhizobia that nodulate this species in its natural habitats on La Palma (Canary Islands) were characterised. The genetic diversity and phylogeny were estimated by RAPD profiles, 16S-RFLP analysis and sequencing of the rrs, recA, glnII and nodC genes. 16S-RFLP grouped the isolates within the Mesorhizobium genus and distinguished nine different ribotypes. Four branches included minority ribotypes (3-5 isolates), whereas another five contained the predominant ribotypes that clustered with reference strains of M. tianshanense/M. gobiense/M. metallidurans, M. caraganae, M. opportunistum, M. ciceri and M. tamadayense. The sequences confirmed the RFLP groupings but resolved additional internal divergence within the M. caraganae group and outlined several potential novel species. The RAPD profiles showed a high diversity at the infraspecific level, except in the M. ciceri group. The nodC phylogeny resolved three symbiotic lineages. A small group of isolates had sequences identical to those of symbiovar ciceri and were only detected in M. ciceri isolates. Another group of sequences represented a novel symbiotic lineage that was associated with two particular chromosomal backgrounds. However, nodC sequences closely related to symbiovar loti predominated in most isolates, and they were detected in several chromosomal backgrounds corresponding to up to nine Mesorhizobium lineages. The results indicated that C. canariense is a promiscuous legume that can be nodulated by several rhizobial species and symbiotypes, which means it will be important to determine the combination of core and symbiotic genes that produce the most effective symbiosis. Copyright © 2013 Elsevier GmbH. All rights reserved.

  4. Pesticide lambda-cyhalothrin degradation using mesorhizobium sp. (s1b) and bartonella sp. (s2b) strains isolated from cotton crop

    Chumro, W.A.; Phulpoto, A.H.; Mangi, S.; Kanhar, N.A.; Ahmed, S.; Qazi, M.A.; Pirzada, T.

    2017-01-01

    Lambda-cyhalothrin (LC), synthetic pyrethroid pesticide is used to control a wide range of pests in variety of agricultural fields. Pesticides are potentially harmful environmental pollutants and pose serious threat to human health. Very limited options are available for environment friendly removal of LC. Interestingly, soil microbes have been known to possess remarkable genetic makeup that helps them to perform vital job in cleaning-up harmful pollutants from the environment. In present study, two LC-degrading bacteria viz. Mesorhizobium sp. strain S1B (Accession no. gb|MF471843|) and Bartonella sp. strain S2B (Accession no. b|MF471844|) were isolated by soil enrichment technique from cotton crop soil and characterized taxonomically using conventional methods and molecular PCR-based 16S rRNA sequence homology. The bacterial strains S1B and S2B achieved 29% and 40% removal of LC (conc. 250 mg/L, w/v), with maximum growth absorbance (OD) of 1.19 +- 0.06 and 1.13+- 0.09, respectively, during 20 days of incubation at 30 degree C and agitation 200 rpm under experimental laboratory circumstances. The percent removal of LC was estimated using UV-Vis Spectroscopy at 287 nm (? max) against the standard curve plotted at different LC concentrations. The bacterial isolates of present study have exhibited substantial efficiency for environmental biodegradation of the pesticide. (author)

  5. Characterization of pH dependent Mn(II) oxidation strategies and formation of a bixbyite-like phase by Mesorhizobium australicum T-G1

    Bohu, Tsing; Santelli, Cara M; Akob, Denise M.; Neu, Thomas R; Ciobota, Valerian; Rösch, Petra; Popp, Jürgen; Nietzsche, Sándor; Küsel, Kirsten

    2015-01-01

    Despite the ubiquity of Mn oxides in natural environments, there are only a few observations of biological Mn(II) oxidation at pH < 6. The lack of low pH Mn-oxidizing bacteria (MOB) isolates limits our understanding of how pH influences biological Mn(II) oxidation in extreme environments. Here, we report that a novel MOB isolate, Mesorhizobium australicum strain T-G1, isolated from an acidic and metalliferous uranium mining area, can oxidize Mn(II) at both acidic and neutral pH using different enzymatic pathways. X-ray diffraction, Raman spectroscopy, and scanning electron microscopy with energy dispersive X-ray spectroscopy revealed that T-G1 initiated bixbyite-like Mn oxide formation at pH 5.5 which coincided with multi-copper oxidase expression from early exponential phase to late stationary phase. In contrast, reactive oxygen species (ROS), particularly superoxide, appeared to be more important for T-G1 mediated Mn(II) oxidation at neutral pH. ROS was produced in parallel with the occurrence of Mn(II) oxidation at pH 7.2 from early stationary phase. Solid phase Mn oxides did not precipitate, which is consistent with the presence of a high amount of H2O2 and lower activity of catalase in the liquid culture at pH 7.2. Our results show that M. australicum T-G1, an acid tolerant MOB, can initiate Mn(II) oxidation by varying its oxidation mechanisms depending on the pH and may play an important role in low pH manganese biogeochemical cycling.

  6. Three phylogenetic groups of nodA and nifH genes in Sinorhizobium and Mesorhizobium isolates from leguminous trees growing in Africa and Latin America.

    Haukka, K; Lindström, K; Young, J P

    1998-02-01

    The diversity and phylogeny of nodA and nifH genes were studied by using 52 rhizobial isolates from Acacia senegal, Prosopis chilensis, and related leguminous trees growing in Africa and Latin America. All of the strains had similar host ranges and belonged to the genera Sinorhizobium and Mesorhizobium, as previously determined by 16S rRNA gene sequence analysis. The restriction patterns and a sequence analysis of the nodA and nifH genes divided the strains into the following three distinct groups: sinorhizobia from Africa, sinorhizobia from Latin America, and mesorhizobia from both regions. In a phylogenetic tree also containing previously published sequences, the nodA genes of our rhizobia formed a branch of their own, but within the branch no correlation between symbiotic genes and host trees was apparent. Within the large group of African sinorhizobia, similar symbiotic gene types were found in different chromosomal backgrounds, suggesting that transfer of symbiotic genes has occurred across species boundaries. Most strains had plasmids, and the presence of plasmid-borne nifH was demonstrated by hybridization for some examples. The nodA and nifH genes of Sinorhizobium teranga ORS1009T grouped with the nodA and nifH genes of the other African sinorhizobia, but Sinorhizobium saheli ORS609T had a totally different nodA sequence, although it was closely related based on the 16S rRNA gene and nifH data. This might be because this S. saheli strain was originally isolated from Sesbania sp., which belongs to a different cross-nodulation group than Acacia and Prosopis spp. The factors that appear to have influenced the evolution of rhizobial symbiotic genes vary in importance at different taxonomic levels.

  7. Characterization of pH dependent Mn(II oxidation strategies and formation of a bixbyite-like phase by Mesorhizobium australicum T-G1

    Tsing eBohu

    2015-07-01

    Full Text Available Despite the ubiquity of Mn oxides in natural environments, there are only a few observations of biological Mn(II oxidation at pH < 6. The lack of low pH Mn-oxidizing bacteria (MOB isolates limits our understanding of how pH influences biological Mn(II oxidation in extreme environments. Here, we report that a novel MOB isolate, Mesorhizobium australicum strain T-G1, isolated from an acidic and metalliferous uranium mining area, can oxidize Mn(II at both acidic and neutral pH using different enzymatic pathways. X-ray diffraction (XRD, Raman spectroscopy, and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS revealed that T-G1 initiated bixbyite-like Mn oxide formation at pH 5.5 which coincided with multi-copper oxidase (MCO expression from early exponential phase to late stationary phase. In contrast, reactive oxygen species (ROS, particularly superoxide, appeared to be more important for T-G1 mediated Mn(II oxidation at neutral pH. ROS was produced in parallel with the occurrence of Mn(II oxidation at pH 7.2 from early stationary phase. Solid phase Mn oxides did not precipitate, which is consistent with the presence of a high amount of H2O2 and lower activity of catalase in the liquid culture at pH 7.2. Our results show that M. australicum T-G1, an acid tolerant MOB, can initiate Mn(II oxidation by varying its oxidation mechanisms depending on the pH and may play an important role in low pH manganese biogeochemical cycling.

  8. Cryopreservation studies of an artificial co-culture between the cobalamin-requiring green alga Lobomonas rostrata and the bacterium Mesorhizobium loti.

    Ridley, Christian J A; Day, John G; Smith, Alison G

    2018-01-01

    Algal-bacterial co-cultures, rather than cultures of algae alone, are regarded as having the potential to enhance productivity and stability in industrial algal cultivation. As with other inocula in biotechnology, to avoid loss of production strains, it is important to develop preservation methods for the long-term storage of these cultures, and one of the most commonly used approaches is cryopreservation. However, whilst there are many reports of cryopreserved xenic algal cultures, little work has been reported on the intentional preservation of both algae and beneficial bacteria in xenic cultures. Instead, studies have focused on the development of methods to conserve the algal strain(s) present, or to avoid overgrowth of bacteria in xenic isolates during the post-thaw recovery phase. Here, we have established a co-cryopreservation method for the long-term storage of both partners in a unialgal-bacterial co-culture. This is an artificial model mutualism between the alga Lobomonas rostrata and the bacterium Mesorhizobium loti , which provides vitamin B 12 (cobalamin) to the alga in return for photosynthate. Using a Planer Kryo 360 controlled-rate cooler, post-thaw viability (PTV) values of 72% were obtained for the co-culture, compared to 91% for the axenic alga. The cultures were successfully revived after 6 months storage in liquid nitrogen, and continued to exhibit mutualism. Furthermore, the alga could be cryopreserved with non-symbiotic bacteria, without bacterial overgrowth occurring. It was also possible to use less controllable passive freezer chambers to cryopreserve the co-cultures, although the PTV was lower. Finally, we demonstrated that an optimised cryopreservation method may be used to prevent the overgrowth potential of non-symbiotic, adventitious bacteria in both axenic and co-cultures of L. rostrata after thawing.

  9. Characterization of pH dependent Mn(II) oxidation strategies and formation of a bixbyite-like phase by Mesorhizobium australicum T-G1

    Bohu, Tsing; Santelli, Cara M; Akob, Denise M.; Neu, Thomas R; Ciobota, Valerian; Rösch, Petra; Popp, Jürgen; Nietzsche, Sándor; Küsel, Kirsten

    2015-01-01

    Despite the ubiquity of Mn oxides in natural environments, there are only a few observations of biological Mn(II) oxidation at pH MOB) isolates limits our understanding of how pH influences biological Mn(II) oxidation in extreme environments. Here, we report that a novel MOB isolate, Mesorhizobium australicum strain T-G1, isolated from an acidic and metalliferous uranium mining area, can oxidize Mn(II) at both acidic and neutral pH using different enzymatic pathways. X-ray diffraction, Raman spectroscopy, and scanning electron microscopy with energy dispersive X-ray spectroscopy revealed that T-G1 initiated bixbyite-like Mn oxide formation at pH 5.5 which coincided with multi-copper oxidase expression from early exponential phase to late stationary phase. In contrast, reactive oxygen species (ROS), particularly superoxide, appeared to be more important for T-G1 mediated Mn(II) oxidation at neutral pH. ROS was produced in parallel with the occurrence of Mn(II) oxidation at pH 7.2 from early stationary phase. Solid phase Mn oxides did not precipitate, which is consistent with the presence of a high amount of H2O2 and lower activity of catalase in the liquid culture at pH 7.2. Our results show that M. australicum T-G1, an acid tolerant MOB, can initiate Mn(II) oxidation by varying its oxidation mechanisms depending on the pH and may play an important role in low pH manganese biogeochemical cycling.

  10. Rhizobia with 16S rRNA and nifH similar to Mesorhizobium huakuii but Novel recA, glnII, nodA and nodC genes are symbionts of New Zealand Carmichaelinae.

    Heng Wee Tan

    Full Text Available New Zealand became geographically isolated about 80 million years ago and this separation gave rise to a unique native flora including four genera of legume, Carmichaelia, Clianthus and Montigena in the Carmichaelinae clade, tribe Galegeae, and Sophora, tribe Sophoreae, sub-family Papilionoideae. Ten bacterial strains isolated from NZ Carmichaelinae growing in natural ecosystems grouped close to the Mesorhizobium huakuii type strain in relation to their 16S rRNA and nifH gene sequences. However, the ten strains separated into four groups on the basis of their recA and glnII sequences: all groups were clearly distinct from all Mesorhizobium type strains. The ten strains separated into two groups on the basis of their nodA sequences but grouped closely together in relation to nodC sequences; all nodA and nodC sequences were novel. Seven strains selected and the M. huakuii type strain (isolated from Astragalus sinicus produced functional nodules on Carmichaelia spp., Clianthus puniceus and A. sinicus but did not nodulate two Sophora species. We conclude that rhizobia closely related to M. huakuii on the basis of 16S rRNA and nifH gene sequences, but with variable recA and glnII genes and novel nodA and nodC genes, are common symbionts of NZ Carmichaelinae.

  11. The NifA-RpoN regulon of Mesorhizobium loti strain R7A and its symbiotic activation by a novel LacI/GalR-family regulator.

    John T Sullivan

    Full Text Available Mesorhizobium loti is the microsymbiont of Lotus species, including the model legume L. japonicus. M. loti differs from other rhizobia in that it contains two copies of the key nitrogen fixation regulatory gene nifA, nifA1 and nifA2, both of which are located on the symbiosis island ICEMlSym(R7A. M. loti R7A also contains two rpoN genes, rpoN1 located on the chromosome outside of ICEMlSym(R7A and rpoN2 that is located on ICEMlSym(R7A. The aims of the current work were to establish how nifA expression was activated in M. loti and to characterise the NifA-RpoN regulon. The nifA2 and rpoN2 genes were essential for nitrogen fixation whereas nifA1 and rpoN1 were dispensable. Expression of nifA2 was activated, possibly in response to an inositol derivative, by a novel regulator of the LacI/GalR family encoded by the fixV gene located upstream of nifA2. Other than the well-characterized nif/fix genes, most NifA2-regulated genes were not required for nitrogen fixation although they were strongly expressed in nodules. The NifA-regulated nifZ and fixU genes, along with nifQ which was not NifA-regulated, were required in M. loti for a fully effective symbiosis although they are not present in some other rhizobia. The NifA-regulated gene msi158 that encodes a porin was also required for a fully effective symbiosis. Several metabolic genes that lacked NifA-regulated promoters were strongly expressed in nodules in a NifA2-dependent manner but again mutants did not have an overt symbiotic phenotype. In summary, many genes encoded on ICEMlSym(R7A were strongly expressed in nodules but not free-living rhizobia, but were not essential for symbiotic nitrogen fixation. It seems likely that some of these genes have functional homologues elsewhere in the genome and that bacteroid metabolism may be sufficiently plastic to adapt to loss of certain enzymatic functions.

  12. Disclosure of the differences of Mesorhizobium loti under the free-living and symbiotic conditions by comparative proteome analysis without bacteroid isolation.

    Tatsukami, Yohei; Nambu, Mami; Morisaka, Hironobu; Kuroda, Kouichi; Ueda, Mitsuyoshi

    2013-07-31

    Rhizobia are symbiotic nitrogen-fixing soil bacteria that show a symbiotic relationship with their host legume. Rhizobia have 2 different physiological conditions: a free-living condition in soil, and a symbiotic nitrogen-fixing condition in the nodule. The lifestyle of rhizobia remains largely unknown, although genome and transcriptome analyses have been carried out. To clarify the lifestyle of bacteria, proteome analysis is necessary because the protein profile directly reflects in vivo reactions of the organisms. In proteome analysis, high separation performance is required to analyze complex biological samples. Therefore, we used a liquid chromatography-tandem mass spectrometry system, equipped with a long monolithic silica capillary column, which is superior to conventional columns. In this study, we compared the protein profile of Mesorhizobium loti MAFF303099 under free-living condition to that of symbiotic conditions by using small amounts of crude extracts. We identified 1,533 and 847 proteins for M. loti under free-living and symbiotic conditions, respectively. Pathway analysis by Kyoto Encyclopedia of Genes and Genomes (KEGG) revealed that many of the enzymes involved in the central carbon metabolic pathway were commonly detected under both conditions. The proteins encoded in the symbiosis island, the transmissible chromosomal region that includes the genes that are highly upregulated under the symbiotic condition, were uniquely detected under the symbiotic condition. The features of the symbiotic condition that have been reported by transcriptome analysis were confirmed at the protein level by proteome analysis. In addition, the genes of the proteins involved in cell surface structure were repressed under the symbiotic nitrogen-fixing condition. Furthermore, farnesyl pyrophosphate (FPP) was found to be biosynthesized only in rhizobia under the symbiotic condition. The obtained protein profile appeared to reflect the difference in phenotypes under the

  13. Phylogenetic diversity of Mesorhizobium in chickpea

    2014-04-29

    Apr 29, 2014 ... uniform flowering/fruiting and seed maturation, etc., hap- pened several ... partnered with legume plants that were found to be ineffective nitrogen fixers ..... vides a rich resource for development of functional markers. PLoS ONE 7 ... Amarger N 2001 Classification of rhizobia based on nodC and. nifH gene ...

  14. Rhizosphere competent Mesorhizobiumloti MP6 induces root hair curling, inhibits Sclerotinia sclerotiorum and enhances growth of Indian mustard (Brassica campestris Mesorhizobium loti MP6 rizosférico competente induz encurvamento do pelo daraiz, inibe Sclerotinia sclerotiorum e estimula o crescimento de mostarda indiana (Brassica campestris

    Shikha Chandra

    2007-03-01

    Full Text Available The bacterial strain Mesorhizobium loti MP6, isolated from root nodules of Mimosa pudica induced growth and yield of Brassica campestris. The isolate MP6 secreted hydroxamate type siderophore in Chrom-Azurol Siderophore (CAS agar medium. Production of hydrocyanic acid (HCN, indole acetic acid (IAA and phosphate solubilizing ability was also recorded under normal growth conditions. Root hair curling was observed through simple glass-slide technique. In vitro study showed a significant increase in population of M. loti MP6 in rhizosphere due to root exudates of B. campestris. In dual culture technique the strain showed a strong antagonistic effect against Sclerotinia sclerotiorum, a white rot pathogen of Brassica campestris. The growth of S. sclerotiorum was inhibited by 75% after prolonged incubation. Efficient root colonization of mustard seedlings was confirmed by using a streptomycin-resistant marker M. loti MP6strep+. The M. loti MP6 coated seeds proved enhanced seed germination, early vegetative growth and grain yield as compared to control. Also, a drastic decline (99% in the incidence of white rot was observed due to application of M. loti MP6.A cepa bacteriana Mesorhizobium loti MP6 isolada de nódulos de raiz de Mimosa pudica induziu o crescimento e o rendimento de Brassica campestris. A cepa MP6 secretou sideróforo do tipo hidroxamato em meio sólido Chrom-Azurol Siderophore (CAS. Em condições normais de crescimento, a cepa foi também capaz de produzir de ácido cianídrico (HCN e acido indolacético (AIA e solubilizar fosfato. O encurvamento do pelo da raiz foi observado usando a simples técnica de lâmina e lamínula. Estudos in vitro mostraram um aumento significativo na população de M. loti MP6 na rizosfera devido aos exsudatos de B. campestris. Empregando-se técnica de co-cultura, a cepa mostrou um grande efeito antagônico contra o fungo Sclerotinia sclerotiorum, o patógeno da podridão branca de Brassica campestris. Ap

  15. Increased protein content of chickpea (Cicer arietinum L.) inoculated with arbuscular mycorrhizal fungi and nitrogen-fixing bacteria under water deficit conditions

    Oliviera, R. S.; Carvalho, P.; Marques, G.; Ferreira, L.; Nunes, M.; Rocha, I.; Ma, Y.; Carvalho, M. F.; Vosátka, Miroslav; Freitas, H.

    2017-01-01

    Roč. 97, č. 13 (2017), s. 4379-4385 ISSN 0022-5142 Institutional support: RVO:67985939 Keywords : drought * grain legume * grain protein content * Mesorhizobium mediterraneum and Rhizophagus irregularis Subject RIV: EI - Biotechnology ; Bionics OBOR OECD: Plant sciences, botany Impact factor: 2.463, year: 2016

  16. Hemoglobin LjGlb1-1 is involved in nodulation and regulates the level of nitric oxide in the Lotus japonicus-Mesorhizobium loti symbiosis.

    Fukudome, Mitsutaka; Calvo-Begueria, Laura; Kado, Tomohiro; Osuki, Ken-Ichi; Rubio, Maria Carmen; Murakami, Ei-Ichi; Nagata, Maki; Kucho, Ken-Ichi; Sandal, Niels; Stougaard, Jens; Becana, Manuel; Uchiumi, Toshiki

    2016-09-01

    Leghemoglobins transport and deliver O2 to the symbiosomes inside legume nodules and are essential for nitrogen fixation. However, the roles of other hemoglobins (Hbs) in the rhizobia-legume symbiosis are unclear. Several Lotus japonicus mutants affecting LjGlb1-1, a non-symbiotic class 1 Hb, have been used to study the function of this protein in symbiosis. Two TILLING alleles with single amino acid substitutions (A102V and E127K) and a LORE1 null allele with a retrotransposon insertion in the 5'-untranslated region (96642) were selected for phenotyping nodulation. Plants of all three mutant lines showed a decrease in long infection threads and nodules, and an increase in incipient infection threads. About 4h after inoculation, the roots of mutant plants exhibited a greater transient accumulation of nitric oxide (NO) than did the wild-type roots; nevertheless, in vitro NO dioxygenase activities of the wild-type, A102V, and E127K proteins were similar, suggesting that the mutated proteins are not fully functional in vivo The expression of LjGlb1-1, but not of the other class 1 Hb of L. japonicus (LjGlb1-2), was affected during infection of wild-type roots, further supporting a specific role for LjGlb1-1. In conclusion, the LjGlb1-1 mutants reveal that this protein is required during rhizobial infection and regulates NO levels. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  17. Increased protein content of chickpea (Cicer arietinum L.) inoculated with arbuscular mycorrhizal fungi and nitrogen-fixing bacteria under water deficit conditions.

    Oliveira, Rui S; Carvalho, Patrícia; Marques, Guilhermina; Ferreira, Luís; Nunes, Mafalda; Rocha, Inês; Ma, Ying; Carvalho, Maria F; Vosátka, Miroslav; Freitas, Helena

    2017-10-01

    Chickpea (Cicer arietinum L.) is a widely cropped pulse and an important source of proteins for humans. In Mediterranean regions it is predicted that drought will reduce soil moisture and become a major issue in agricultural practice. Nitrogen (N)-fixing bacteria and arbuscular mycorrhizal (AM) fungi have the potential to improve plant growth and drought tolerance. The aim of the study was to assess the effects of N-fixing bacteria and AM fungi on the growth, grain yield and protein content of chickpea under water deficit. Plants inoculated with Mesorhizobium mediterraneum or Rhizophagus irregularis without water deficit and inoculated with M. mediterraneum under moderate water deficit had significant increases in biomass. Inoculation with microbial symbionts brought no benefits to chickpea under severe water deficit. However, under moderate water deficit grain crude protein was increased by 13%, 17% and 22% in plants inoculated with M. mediterraneum, R. irregularis and M. mediterraneum + R. irregularis, respectively. Inoculation with N-fixing bacteria and AM fungi has the potential to benefit agricultural production of chickpea under water deficit conditions and to contribute to increased grain protein content. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  18. ORF Alignment: NC_002678 [GENIUS II[Archive

    Full Text Available ator ... [Mesorhizobium loti MAFF303099] ... Length = 179 ... Query: 14 ... REKRERTRTLIVEAGAMLLAERPR...EGLTVDAVVEAAGVAKGTFYYHFQSIDELASAVGEK 73 ... REKRERTRTLIVEAGAMLLAERPREGLTVD...AVVEAAGVAKGTFYYHFQSIDELASAVGEK Sbjct: 1 ... REKRERTRTLIVEAGAMLLAERPREGLTVDAVVEAAGVAKGTFYYHFQSIDELASAVGEK 60 ... Q

  19. ORF Alignment: NC_002678 [GENIUS II[Archive

    Full Text Available nase ... [Mesorhizobium loti MAFF303099] ... Length = 157 ... Query: 700 KNAEQDWLKTNLARFSRMLQGERD...LATVSRLIMSELAPLVNAQYGVFYVTNRDEEESYLE 759 ... KNAEQDWLKTNLARFSRMLQGERDLATVS...RLIMSELAPLVNAQYGVFYVTNRDEEESYLE Sbjct: 1 ... KNAEQDWLKTNLARFSRMLQGERDLATVSRLIMSELAPLVNAQYGVFYVTNRDEEESYLE 60 ...

  20. ORF Sequence: NC_002678 [GENIUS II[Archive

    Full Text Available NC_002678 gi|13471138 >gi|13471138|ref|NP_102707.1| transcriptional regulatory protein, nodulation competit...iveness determinant [Mesorhizobium loti MAFF303099] MTNESDTRSAELAELTADIVSAYVSNNPLPV

  1. ORF Alignment: NC_002678 [GENIUS II[Archive

    Full Text Available ucosamine-6-phosphate deacetylase ... [Mesorhizobium loti MAFF303099] ... Length = 381 ... Query: 7 ... LTGARIFD...GDDWHDDAALVVRDGLVEAIVPSGAIARDVRAVDTGGGMLVPGFVDIQVNGG 66 ... LTGARIFD...GDDWHDDAALVVRDGLVEAIVPSGAIARDVRAVDTGGGMLVPGFVDIQVNGG Sbjct: 1 ... LTGARIFDGDDWHDDAALVVRDGLVEAIVPSGAIARD

  2. ORF Alignment: NC_002678 [GENIUS II[Archive

    Full Text Available NC_002678 gi|13474471 >1gkpA 2 454 5 422 3e-10 ... ref|NP_106039.1| creatinine deamin...ase [Mesorhizobium loti MAFF303099] ... dbj|BAB51825.1| creatinine deaminase [Mesorhizobium loti ...

  3. ORF Alignment: NC_002678 [GENIUS II[Archive

    Full Text Available NC_002678 gi|13473528 >1u07A 4 89 172 254 2e-09 ... ref|NP_105096.1| energy transduce...r TonB [Mesorhizobium loti MAFF303099] ... dbj|BAB50882.1| energy transducer; TonB [Mesorhizobium ...

  4. Phylogeny of Symbiotic Genes and the Symbiotic Properties of Rhizobia Specific to Astragalus glycyphyllos L.

    Gnat, Sebastian; Małek, Wanda; Oleńska, Ewa; Wdowiak-Wróbel, Sylwia; Kalita, Michał; Łotocka, Barbara; Wójcik, Magdalena

    2015-01-01

    The phylogeny of symbiotic genes of Astragalus glycyphyllos L. (liquorice milkvetch) nodule isolates was studied by comparative sequence analysis of nodA, nodC, nodH and nifH loci. In all these genes phylograms, liquorice milkvetch rhizobia (closely related to bacteria of three species, i.e. Mesorhizobium amorphae, Mesorhizobium septentrionale and Mesorhizobium ciceri) formed one clearly separate cluster suggesting the horizontal transfer of symbiotic genes from a single ancestor to the bacteria being studied. The high sequence similarity of the symbiotic genes of A. glycyphyllos rhizobia (99-100% in the case of nodAC and nifH genes, and 98-99% in the case of nodH one) points to the relatively recent (in evolutionary scale) lateral transfer of these genes. In the nodACH and nifH phylograms, A. glycyphyllos nodule isolates were grouped together with the genus Mesorhizobium species in one monophyletic clade, close to M. ciceri, Mesorhizobium opportunistum and Mesorhizobium australicum symbiovar biserrulae bacteria, which correlates with the close relationship of these rhizobia host plants. Plant tests revealed the narrow host range of A. glycyphyllos rhizobia. They formed effective symbiotic interactions with their native host (A. glycyphyllos) and Amorpha fruticosa but not with 11 other fabacean species. The nodules induced on A. glycyphyllos roots were indeterminate with apical, persistent meristem, an age gradient of nodule tissues and cortical vascular bundles. To reflect the symbiosis-adaptive phenotype of rhizobia, specific for A. glycyphyllos, we propose for these bacteria the new symbiovar "glycyphyllae", based on nodA and nodC genes sequences.

  5. Recombination and horizontal transfer of nodulation and ACC deaminase (acdS) genes within Alpha- and Betaproteobacteria nodulating legumes of the Cape Fynbos biome.

    Lemaire, Benny; Van Cauwenberghe, Jannick; Chimphango, Samson; Stirton, Charles; Honnay, Olivier; Smets, Erik; Muasya, A Muthama

    2015-11-01

    The goal of this work is to study the evolution and the degree of horizontal gene transfer (HGT) within rhizobial genera of both Alphaproteobacteria (Mesorhizobium, Rhizobium) and Betaproteobacteria (Burkholderia), originating from South African Fynbos legumes. By using a phylogenetic approach and comparing multiple chromosomal and symbiosis genes, we revealed conclusive evidence of high degrees of horizontal transfer of nodulation genes among closely related species of both groups of rhizobia, but also among species with distant genetic backgrounds (Rhizobium and Mesorhizobium), underscoring the importance of lateral transfer of symbiosis traits as an important evolutionary force among rhizobia of the Cape Fynbos biome. The extensive exchange of symbiosis genes in the Fynbos is in contrast with a lack of significant events of HGT among Burkholderia symbionts from the South American Cerrado and Caatinga biome. Furthermore, homologous recombination among selected housekeeping genes had a substantial impact on sequence evolution within Burkholderia and Mesorhizobium. Finally, phylogenetic analyses of the non-symbiosis acdS gene in Mesorhizobium, a gene often located on symbiosis islands, revealed distinct relationships compared to the chromosomal and symbiosis genes, suggesting a different evolutionary history and independent events of gene transfer. The observed events of HGT and incongruence between different genes necessitate caution in interpreting topologies from individual data types. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  6. ORF Alignment: NC_002678 [GENIUS II[Archive

    Full Text Available NC_002678 gi|13472874 >1b4uB 49 289 86 299 5e-14 ... ref|NP_104441.1| encapsulation p...rotein CapA [Mesorhizobium loti MAFF303099] ... dbj|BAB50227.1| encapsulation protein; CapA ...

  7. ORF Alignment: NC_006177 [GENIUS II[Archive

    Full Text Available NC_006177 gi|51893967 >1b4uB 49 289 86 299 5e-14 ... ref|NP_104441.1| encapsulation p...rotein CapA [Mesorhizobium loti MAFF303099] ... dbj|BAB50227.1| encapsulation protein; CapA ...

  8. ORF Alignment: NC_002967 [GENIUS II[Archive

    Full Text Available NC_002967 gi|42528039 >1b4uB 49 289 86 299 5e-14 ... ref|NP_104441.1| encapsulation p...rotein CapA [Mesorhizobium loti MAFF303099] ... dbj|BAB50227.1| encapsulation protein; CapA ...

  9. ORF Alignment: NC_002678 [GENIUS II[Archive

    Full Text Available NC_002678 gi|13475854 >1el5A 4 378 18 430 4e-33 ... ref|NP_107424.1| agaE protein, conversion of agropini...c acid to mannopinic acid ... [Mesorhizobium loti MAFF303099] dbj|BAB53210.1| Aga

  10. ORF Alignment: NC_002678 [GENIUS II[Archive

    Full Text Available NC_002678 gi|13475930 >1el5A 6 379 7 420 7e-42 ... ref|NP_107500.1| AgaE protein, conversion of agropini...c acid to mannopinic acid ... [Mesorhizobium loti MAFF303099] dbj|BAB53286.1| AgaE

  11. ORF Alignment: NC_002679 [GENIUS II[Archive

    Full Text Available NC_002679 gi|13488188 >1el5A 4 377 26 437 3e-36 ... ref|NP_085608.1| agaE(conversion of agropini...c acid to mannopinic acid) ... [Mesorhizobium loti MAFF303099] dbj|BAB54449.1| AgaE ...

  12. NCBI nr-aa BLAST: CBRC-TNIG-22-0185 [SEVENS

    Full Text Available CBRC-TNIG-22-0185 ref|NP_103831.1| putative manganese transport protein MntH [Mesor...hizobium loti MAFF303099] sp|Q98I99|MNTH_RHILO Probable manganese transport protein mntH dbj|BAB49617.1| manga

  13. LysM domains mediate lipochitin-oligosaccharide recognition and Nfr genes extend the symbiotic host range

    Radutoiu, Simona; Madsen, Lene H; Madsen, Esben B

    2007-01-01

    and Nfr5 Nod-factor receptor genes in Medicago truncatula and L. filicaulis, extends their host range to include bacterial strains, Mesorhizobium loti or DZL, normally infecting L. japonicus. As a result, the symbiotic program is induced, nodules develop and infection threads are formed. Using L...

  14. GIPSy

    Soares, Siomar C; Geyik, Hakan; Ramos, Rommel T J

    2016-01-01

    in Escherichia coli CFT073; 1 MI for Burkholderia pseudomallei K96243, which seems to be a miscellaneous island; 1 RI of Acinetobacter baumannii AYE, named AbaR1; and, 1 SI of Mesorhizobium loti MAFF303099 presenting a mosaic structure. GIPSy is the first life-style-specific genomic island prediction software...

  15. Phenotypic diversity and plant growth promoting characteristics of ...

    Chickpea (Cicer arietinum L.) is one of the major sources of dietary protein for majority of Ethiopian population. It also maintains soil fertility through its symbiotic nitrogen-fixation in association with Mesorhizobium species. Therefore, this study was aimed at isolation, characterization and selection of symbiotically effective ...

  16. Response of chickpea ( Cicer arietinum L.) to inoculation with native ...

    The results from the field and pot experiments indicated that chickpea crop yield can be improved using proper Mesorhizobium inoculation. Inoculation had a pronounced effect on grain yield, yield component, total N uptake, grain protein content, percentage N derived from the atmosphere (%Ndfa) for the seed, and amount ...

  17. The Symbiotic Performance of Chickpea Rhizobia Can Be Improved by Additional Copies of the clpB Chaperone Gene.

    Paço, Ana; Brígido, Clarisse; Alexandre, Ana; Mateos, Pedro F; Oliveira, Solange

    2016-01-01

    The ClpB chaperone is known to be involved in bacterial stress response. Moreover, recent studies suggest that this protein has also a role in the chickpea-rhizobia symbiosis. In order to improve both stress tolerance and symbiotic performance of a chickpea microsymbiont, the Mesorhizobium mediterraneum UPM-Ca36T strain was genetically transformed with pPHU231 containing an extra-copy of the clpB gene. To investigate if the clpB-transformed strain displays an improved stress tolerance, bacterial growth was evaluated under heat and acid stress conditions. In addition, the effect of the extra-copies of the clpB gene in the symbiotic performance was evaluated using plant growth assays (hydroponic and pot trials). The clpB-transformed strain is more tolerant to heat shock than the strain transformed with pPHU231, supporting the involvement of ClpB in rhizobia heat shock tolerance. Both plant growth assays showed that ClpB has an important role in chickpea-rhizobia symbiosis. The nodulation kinetics analysis showed a higher rate of nodule appearance with the clpB-transformed strain. This strain also induced a greater number of nodules and, more notably, its symbiotic effectiveness increased ~60% at pH5 and 83% at pH7, compared to the wild-type strain. Furthermore, a higher frequency of root hair curling was also observed in plants inoculated with the clpB-transformed strain, compared to the wild-type strain. The superior root hair curling induction, nodulation ability and symbiotic effectiveness of the clpB-transformed strain may be explained by an increased expression of symbiosis genes. Indeed, higher transcript levels of the nodulation genes nodA and nodC (~3 folds) were detected in the clpB-transformed strain. The improvement of rhizobia by addition of extra-copies of the clpB gene may be a promising strategy to obtain strains with enhanced stress tolerance and symbiotic effectiveness, thus contributing to their success as crop inoculants, particularly under

  18. The Symbiotic Performance of Chickpea Rhizobia Can Be Improved by Additional Copies of the clpB Chaperone Gene.

    Ana Paço

    Full Text Available The ClpB chaperone is known to be involved in bacterial stress response. Moreover, recent studies suggest that this protein has also a role in the chickpea-rhizobia symbiosis. In order to improve both stress tolerance and symbiotic performance of a chickpea microsymbiont, the Mesorhizobium mediterraneum UPM-Ca36T strain was genetically transformed with pPHU231 containing an extra-copy of the clpB gene. To investigate if the clpB-transformed strain displays an improved stress tolerance, bacterial growth was evaluated under heat and acid stress conditions. In addition, the effect of the extra-copies of the clpB gene in the symbiotic performance was evaluated using plant growth assays (hydroponic and pot trials. The clpB-transformed strain is more tolerant to heat shock than the strain transformed with pPHU231, supporting the involvement of ClpB in rhizobia heat shock tolerance. Both plant growth assays showed that ClpB has an important role in chickpea-rhizobia symbiosis. The nodulation kinetics analysis showed a higher rate of nodule appearance with the clpB-transformed strain. This strain also induced a greater number of nodules and, more notably, its symbiotic effectiveness increased ~60% at pH5 and 83% at pH7, compared to the wild-type strain. Furthermore, a higher frequency of root hair curling was also observed in plants inoculated with the clpB-transformed strain, compared to the wild-type strain. The superior root hair curling induction, nodulation ability and symbiotic effectiveness of the clpB-transformed strain may be explained by an increased expression of symbiosis genes. Indeed, higher transcript levels of the nodulation genes nodA and nodC (~3 folds were detected in the clpB-transformed strain. The improvement of rhizobia by addition of extra-copies of the clpB gene may be a promising strategy to obtain strains with enhanced stress tolerance and symbiotic effectiveness, thus contributing to their success as crop inoculants

  19. Dicty_cDB: Contig-U16444-1 [Dicty_cDB

    Full Text Available 001503 |pid:none) Burkholderia glumae BGR1 chromos... 130 5e-30 AF511570_1( AF511570 |pid:none) Uncultured soil...) Pseudomonas syringae pv. phaseo... 80 2e-13 AF511571_1( AF511571 |pid:none) Uncultured soil bacterium clon...00390 |pid:none) Mesorhizobium sp. BNC1, complete... 57 3e-09 AF511572_1( AF511572 |pid:none) Uncultured soil

  20. Lotus japonicus nodulation requires two GRAS domain regulators, one of which is functionally conserved in a non-legume

    Heckmann, Anne Birgitte Lau; Lombardo, Fabien; Miwa, Hiroki

    2006-01-01

    A new nodulation-defective mutant of Lotus japonicus does not initiate nodule cortical cell division in response to Mesorhizobium loti, but induces root hair deformation, Nod factor-induced calcium spiking, and mycorrhization. This phenotype, together with mapping data, suggested that the mutation...... could be in the ortholog of the Medicago truncatula NSP1 gene (MtNSP1). The sequence of the orthologous gene (LjNSP1) in the L. japonicus mutant (Ljnsp1-1) revealed a mutation causing a premature stop resulting in loss of the C-terminal 23 amino acids. We also sequenced the NSP2 gene from L. japonicus...

  1. Expression and Purification of BmrI Restriction Endonuclease and Its N-terminal Cleavage Domain Variants

    Bao, Yongming; Higgins, Lauren; Zhang, Penghua; Chan, Siu-hong; Laget, Sophie; Sweeney, Suzanne; Lunnen, Keith; Xu, Shuang-yong

    2007-01-01

    BmrI (ACTGGG N5/N4) is one of the few metal-independent restriction endonucleases (REases) found in bacteria. The BmrI restriction-modification system was cloned by the methylase selection method, inverse PCR, and PCR. BmrI REase shows significant amino acid sequence identity to BfiI and a putative endonuclease MspBNCORF3798 from the sequenced Mesorhizobium sp. BNC1 genome. The EDTA-resistant BmrI REase was successfully over-expressed in a pre-modified E. coli strain from pET21a or pBAC-expIQ...

  2. Lotus japonicus nodulation requires two GRAS-domain regulators, NSP1 and NSP2

    Heckmann, Anne Birgitte Lau; Lombardo, Fabien; Miwa, Hiroki

    A nodulation-defective mutant of Lotus japonicus does not initiate nodule cortical cell division in response to Mesorhizobium loti, but induces root hair deformation, Nod factor-induced calcium spiking, and mycorrhization. We have shown that this mutant has a premature stop in the NSP1 (Nodulation...... Signalling Pathway 1) gene (Ljnsp1-1) resulting in loss of the C-terminal 23 amino acids (aa) and we recently identified another mutant in NSP1 (Ljnsp1-2) with a truncated protein of 341 aa. Additionally, we have sequenced and isolated a mutant in LjNSP2 (Ljnsp2-3) that has a premature stop codon showing...

  3. Extended local similarity analysis (eLSA) reveals unique associations between bacterial community structure and odor emission during pig carcasses decomposition.

    Ki, Bo-Min; Ryu, Hee Wook; Cho, Kyung-Suk

    2018-02-22

    Soil burial and composting methods have been widely used for the disposal of pig carcasses. The relationship between bacterial community structure and odor emission was examined using extended local similarity analysis (eLSA) during the degradation of pig carcasses in soil and compost. In soil, Hyphomicrobium, Niastella, Rhodanobacter, Polaromonas, Dokdonella and Mesorhizobium were associated with the emission of sulfur-containing odors such as hydrogen sulfide, methyl mercaptan and dimethyl disulfide. Sphingomonas, Rhodanobacter, Mesorhizobium, Dokdonella, Leucobacter and Truepera were associated with the emission of nitrogen-containing odors including ammonia and trimetylamine. In compost, however, Carnobacteriaceae, Lachnospiaceae and Clostridiales were highly correlated with the emission of sulfur-containing odors, while Rumincoccaceae was associated with the emission of nitrogen-containing odors. The emission of organic acids was closely related to Massilia, Sphaerobacter and Bradyrhizobiaceae in soil, but to Actinobacteria, Sporacetigenium, Micromonosporaceae and Solirubrobacteriales in compost. This study suggests that network analysis using eLSA is a useful strategy for exploring the mechanisms of odor emission during biodegradation of pig carcasses.

  4. Diversity analysis of diazotrophic bacteria associated with the roots of tea (Camellia sinensis (L.) O. Kuntze).

    Gulati, Arvind; Sood, Swati; Rahi, Praveen; Thakur, Rishu; Chauhan, Sunita; Chawla, Isha

    2011-06-01

    The diversity elucidation by amplified ribosomal DNA restriction analysis and 16S rDNA sequencing of 96 associative diazotrophs, isolated from the feeder roots of tea on enriched nitrogen-free semisolid media, revealed the predominance of Gram-positive over Gram-negative bacteria within the Kangra valley in Himachal Pradesh, India. The Gram-positive bacteria observed belong to two taxonomic groupings; Firmicutes, including the genera Bacillus and Paenibacillus; and Actinobacteria, represented by the genus Microbacterium. The Gram-negative bacteria included alpha-Proteobacteria genera Brevundimonas, Rhizobium, and Mesorhizobium; gamma-Proteobacteria genera Pseudomonas and Stenotrophomonas; and beta-Proteobacteria genera Azospira, Burkholderia, Delftia, Herbaspirillum and Ralstonia. The low level of similarity of two isolates, with the type strains Paenibacillus xinjiangensis and Mesorhizobium albiziae, suggests the possibility of raising species novum. The bacterial strains of different phylogenetic groups exhibited distinct carbon-source utilization patterns and fatty acid methyl ester profiles. The strains differed in their nitrogenase activities with relatively high activity seen in the Gramnegative strains exhibiting the highest similarity to Azospira oryzae, Delftia lacustris and Herbaspirillum huttiense.

  5. Dynamics of ethylene production in response to compatible Nod factor

    Reid, Dugald; Liu, Huijun; Kelly, Simon

    2018-01-01

    Establishment of symbiotic nitrogen-fixation in legumes is regulated by the plant hormone ethylene, but it has remained unclear whether and how its biosynthesis is regulated by the symbiotic pathway. We established a sensitive ethylene detection system for Lotus japonicus and found that ethylene...... production increased as early as six hours after inoculation with Mesorhizobium loti. This ethylene response was dependent on Nod factor production by compatible rhizobia. Analyses of nodulation mutants showed that perception of Nod factor was required for ethylene emission, while downstream transcription...... factors including CYCLOPS, NIN and ERN1 were not required for this response. Activation of the nodulation signalling pathway in spontaneously nodulating mutants was also sufficient to elevate ethylene production. Ethylene signalling is controlled by EIN2, which is duplicated in L. japonicus. We obtained...

  6. The plant growth promoting substance, lumichrome, mimics starch and ethylene-associated symbiotic responses in lotus and tomato roots

    Liezel eGouws

    2012-06-01

    Full Text Available Symbiosis involves responses that maintain the plant host and symbiotic partner’s genetic program; yet these cues are far from elucidated. Here we describe the effects of lumichrome, a flavin identified from Rhizobium spp., applied to lotus (Lotus japonicus and tomato (Solanum lycopersicum. Combined transcriptional and metabolite analyses suggest that both species shared common pathways that were altered in response to this application under replete, sterile conditions. These included genes involved in symbiosis, as well as transcriptional and metabolic responses related to enhanced starch accumulation and altered ethylene metabolism. Lumichrome priming also resulted in altered colonization with either Mesorhizobium loti (for lotus or Glomus intraradices/Glomus mossea (for tomato. It enhanced nodule number but not nodule formation in lotus; while leading to enhanced hyphae initiation and delayed arbuscule maturation in tomato.

  7. Tolerância de rizóbios de diferentes procedências ao zinco, cobre e cádmio Tolerance of rhizobia genera from different origins to zinc, copper and cadmium

    Alexandre Matsuda

    2002-03-01

    Full Text Available Sessenta estirpes/isolados dos gêneros Bradyrhizobium, Rhizobium, Sinorhizobium, Mesorhizobium e Azorhizobium, procedentes de diferentes locais (Mata Atlântica, Amazônia, culturas agrícolas e experimentos com metais pesados e de espécies hospedeiras pertencentes às subfamílias Papilionoideae, Mimosoideae e Caesalpinoideae, foram avaliadas quanto à tolerância a Zn, Cu e Cd em meio YMA modificado pela adição de tampões biológicos (HEPES e MES e suplementados com Cu (0 a 60 mg L-1, Cd (0 a 60 mg L-1 e Zn (0 a 1.000 mg L-1. Mediante padrões de crescimento atribuídos às culturas nas diferentes concentrações dos metais, avaliaram-se as concentrações máximas toleradas e as doses tóxicas destes metais para redução de crescimento em 25% (DT25 e 50% (DT50. Não houve influência da procedência na concentração máxima de metal tolerada. A ordem de sensibilidade aos metais, considerando-se as concentrações máximas toleradas, foi Azorhizobium > Rhizobium = Mesorhizobium = Sinorhizobium > Bradyrhizobium. A DT25 e a DT50 foram úteis para diferenciarem estirpes/isolados de um mesmo gênero, que atingiram a mesma concentração máxima tolerada a Zn, Cu e Cd. A ordem de toxicidade dos metais estudados foi Cu > Cd > Zn.Sixty strains/isolates of the genera Bradyrhizobium, Rhizobium, Sinorhizobium, Mesorhizobium and Azorhizobium, isolated from different hosts (legume subfamilies: Papilionoideae, Mimosoideae and Caesalpinoideae and location (Atlantic Forest, Amazon region, crop plantings and heavy metal experiments, were evaluated for Zn, Cu and Cd tolerance in YMA medium modified by the addition of biological buffers (HEPES and MES and supplemented with Cu (0 to 60 mg L-1, Cd (0 to 60 mg L-1, and Zn (0 to 1,000 mg L-1sulphates. Growth standards were applied to evaluate rhizobia cultures growth at different metal concentrations, allowing evaluation of highest tolerated concentrations of Zn, Cu, and Cd and the toxic doses

  8. Defects in rhizobial cyclic glucan and lipopolysaccharide synthesis alter legume gene expression during nodule development

    D'Antuono, Alejandra L; Ott, Thomas; Krusell, Lene

    2008-01-01

    cDNA array technology was used to compare transcriptome profiles of Lotus japonicus roots inoculated with a Mesorhizobium loti wild-type and two mutant strains affected in cyclic beta(1-2) glucan synthesis (cgs) and in lipopolysaccharide synthesis (lpsbeta2). Expression of genes associated...... with the development of a fully functional nodule was significantly affected in plants inoculated with the cgs mutant. Array results also revealed that induction of marker genes for nodule development was delayed when plants were inoculated with the lpsbeta2 mutant. Quantitative real-time reverse......-transcriptase polymerase chain reaction was used to quantify gene expression of a subset of genes involved in plant defense response, redox metabolism, or genes that encode for nodulins. The majority of the genes analyzed in this study were more highly expressed in roots inoculated with the wild type compared with those...

  9. Identification of symbiotically defective mutants of Lotus japonicus affected in infection thread growth

    Lombardo, Fabien; Heckmann, Anne Birgitte Lau; Miwa, Hiroki

    2006-01-01

    During the symbiotic interaction between legumes and rhizobia, the host cell plasma membrane and associated plant cell wall invaginate to form a tunnel-like infection thread, a structure in which bacteria divide to reach the plant root cortex. We isolated four Lotus japonicus mutants that make...... infection pockets in root hairs but form very few infection threads after inoculation with Mesorhizobium loti. The few infection threads that did initiate in the mutants usually did not progress further than the root hair cell. These infection-thread deficient (itd) mutants were unaffected for early...... symbiotic responses such as calcium spiking, root hair deformation, and curling, as well as for the induction of cortical cell division and the arbuscular mycorrhizal symbiosis. Complementation tests and genetic mapping indicate that itd2 is allelic to Ljsym7, whereas the itd1, itd3, and itd4 mutations...

  10. Insight into cofactor recognition in arylamine N-acetyltransferase enzymes

    Xu, Ximing; Li de la Sierra-Gallay, Inés; Kubiak, Xavier Jean Philippe

    2015-01-01

    Arylamine N-acetyltransferases (NATs) are xenobiotic metabolizing enzymes that catalyze the acetyl-CoA-dependent acetylation of arylamines. To better understand the mode of binding of the cofactor by this family of enzymes, the structure of Mesorhizobium loti NAT1 [(RHILO)NAT1] was determined...... for Bacillus anthracis NAT1 and Homo sapiens NAT2. Therefore, in contrast to previous data, this study shows that different orthologous NATs can bind their cofactors in a similar way, suggesting that the mode of binding CoA in this family of enzymes is less diverse than previously thought. Moreover......, it supports the notion that the presence of the `mammalian/eukaryotic insertion loop' in certain NAT enzymes impacts the mode of binding CoA by imposing structural constraints....

  11. The abundance and diversity of legume-nodulating rhizobia in 28-year-old plantations of tropical, subtropical, and exotic tree species: a case study from the Forest Reserve of Bandia, Senegal.

    Sene, Godar; Thiao, Mansour; Samba-Mbaye, Ramatoulaye; Khasa, Damase; Kane, Aboubacry; Mbaye, Mame Samba; Beaulieu, Marie-Ève; Manga, Anicet; Sylla, Samba Ndao

    2013-01-01

    Several fast-growing and multipurpose tree species have been widely used in West Africa to both reverse the tendency of land degradation and restore soil productivity. Although beneficial effects have been reported on soil stabilization, there still remains a lack of information about their impact on soil microorganisms. Our investigation has been carried out in exotic and native tree plantations of 28 years and aimed to survey and compare the abundance and genetic diversity of natural legume-nodulating rhizobia (LNR). The study of LNR is supported by the phylogenetic analysis which clustered the isolates into three genera: Bradyrhizobium, Mesorhizobium, and Sinorhizobium. The results showed close positive correlations between the sizes of LNR populations estimated both in the dry and rainy seasons and the presence of legume tree hosts. There were significant increases in Rhizobium spp. population densities in response to planting with Acacia spp., and high genetic diversities and richness of genotypes were fittest in these tree plantations. This suggests that enrichment of soil Rhizobium spp. populations is host specific. The results indicated also that species of genera Mesorhizobium and Sinorhizobium were lacking in plantations of non-host species. By contrast, there was a widespread distribution of Bradyrhizobium spp. strains across the tree plantations, with no evident specialization in regard to plantation type. Finally, the study provides information about the LNR communities associated with a range of old tree plantations and some aspects of their relationships to soil factors, which may facilitate the management of man-made forest systems that target ecosystem rehabilitation and preservation of soil biota.

  12. Bacterial and diazotrophic diversities of endophytes in Dendrobium catenatum determined through barcoded pyrosequencing.

    Li, Ou; Xiao, Rong; Sun, Lihua; Guan, Chenglin; Kong, Dedong; Hu, Xiufang

    2017-01-01

    As an epiphyte orchid, Dendrobium catenatum relies on microorganisms for requisite nutrients. Metagenome pyrosequencing based on 16S rRNA and nifH genes was used to characterize the bacterial and diazotrophic communities associated with D. catenatum collected from 5 districts in China. Based on Meta-16S rRNA sequencing, 22 bacterial phyla and 699 genera were identified, distributed as 125 genera from 8 phyla and 319 genera from 10 phyla shared by all the planting bases and all the tissues, respectively. The predominant Proteobacteria varied from 71.81% (GZ) to 96.08% (YN), and Delftia (10.39-38.42%), Burkholderia (2.71-15.98%), Escherichia/Shigella (4.90-25.12%), Pseudomonas (2.68-30.72%) and Sphingomonas (1.83-2.05%) dominated in four planting bases. Pseudomonas (17.94-22.06%), Escherichia/Shigella (6.59-11.59%), Delftia (9.65-22.14%) and Burkholderia (3.12-11.05%) dominated in all the tissues. According to Meta-nifH sequencing, 4 phyla and 45 genera were identified, while 17 genera and 24 genera from 4 phyla were shared by all the planting bases and all the tissues, respectively. Burkholderia and Bradyrhizobium were the most popular in the planting bases, followed by Methylovirgula and Mesorhizobium. Mesorhizobium was the most popular in different tissues, followed by Beijerinckia, Xanthobacter, and Burkholderia. Among the genera, 39 were completely overlapped with the results based on the 16S rRNA gene. In conclusion, abundant bacteria and diazotrophs were identified in common in different tissues of D. catenatum from five planting bases, which might play a great role in the supply of nutrients such as nitrogen. The exact abundance of phylum and genus on the different tissues from different planting bases need deeper sequencing with more samples.

  13. Molecular diversity of legume root-nodule bacteria in Kakadu National Park, Northern Territory, Australia.

    Bénédicte Lafay

    2007-03-01

    Full Text Available Symbiotic relationships between leguminous plants (family Fabaceae and nodule-forming bacteria in Australia native ecosystems remain poorly characterized despite their importance. Most studies have focused on temperate parts of the country, where the use of molecular approaches have already revealed the presence of Bradyrhizobium, Ensifer (formerly Sinorhizobium, Mesorhizobium and Rhizobium genera of legume root-nodule bacteria. We here provide the first molecular characterization of nodulating bacteria from tropical Australia.45 nodule-forming bacterial strains, isolated from eight native legume hosts at eight locations in Kakadu National Park, Northern Territory, Australia, were examined for their genetic diversity and phylogenetic position. Using SSU rDNA PCR-RFLPs and phylogenetic analyses, our survey identified nine genospecies, two of which, Bradyrhizobium genospp. B and P, had been previously identified in south-eastern Australia and one, Mesorhizobium genospecies AA, in southern France. Three of the five newly characterized Bradyrhizobium genospecies were more closely related to B. japonicum USDA110, whereas the other two belonged to the B. elkanii group. All five were each more closely related to strains sampled in various tropical areas outside Australia than to strains known to occur in Australia. We also characterized an entirely novel nodule-forming lineage, phylogenetically distant from any previously described rhizobial and non-rhizobial legume-nodulating lineage within the Rhizobiales.Overall, the present results support the hypothesis of tropical areas being centres of biodiversity and diversification for legume root-nodule bacteria and confirm the widespread occurrence of Bradyrhizobium genosp. B in continental Australia.

  14. Bacterial and diazotrophic diversities of endophytes in Dendrobium catenatum determined through barcoded pyrosequencing.

    Ou Li

    Full Text Available As an epiphyte orchid, Dendrobium catenatum relies on microorganisms for requisite nutrients. Metagenome pyrosequencing based on 16S rRNA and nifH genes was used to characterize the bacterial and diazotrophic communities associated with D. catenatum collected from 5 districts in China. Based on Meta-16S rRNA sequencing, 22 bacterial phyla and 699 genera were identified, distributed as 125 genera from 8 phyla and 319 genera from 10 phyla shared by all the planting bases and all the tissues, respectively. The predominant Proteobacteria varied from 71.81% (GZ to 96.08% (YN, and Delftia (10.39-38.42%, Burkholderia (2.71-15.98%, Escherichia/Shigella (4.90-25.12%, Pseudomonas (2.68-30.72% and Sphingomonas (1.83-2.05% dominated in four planting bases. Pseudomonas (17.94-22.06%, Escherichia/Shigella (6.59-11.59%, Delftia (9.65-22.14% and Burkholderia (3.12-11.05% dominated in all the tissues. According to Meta-nifH sequencing, 4 phyla and 45 genera were identified, while 17 genera and 24 genera from 4 phyla were shared by all the planting bases and all the tissues, respectively. Burkholderia and Bradyrhizobium were the most popular in the planting bases, followed by Methylovirgula and Mesorhizobium. Mesorhizobium was the most popular in different tissues, followed by Beijerinckia, Xanthobacter, and Burkholderia. Among the genera, 39 were completely overlapped with the results based on the 16S rRNA gene. In conclusion, abundant bacteria and diazotrophs were identified in common in different tissues of D. catenatum from five planting bases, which might play a great role in the supply of nutrients such as nitrogen. The exact abundance of phylum and genus on the different tissues from different planting bases need deeper sequencing with more samples.

  15. Bacterial and diazotrophic diversities of endophytes in Dendrobium catenatum determined through barcoded pyrosequencing

    Li, Ou; Sun, Lihua; Guan, Chenglin; Kong, Dedong

    2017-01-01

    As an epiphyte orchid, Dendrobium catenatum relies on microorganisms for requisite nutrients. Metagenome pyrosequencing based on 16S rRNA and nifH genes was used to characterize the bacterial and diazotrophic communities associated with D. catenatum collected from 5 districts in China. Based on Meta-16S rRNA sequencing, 22 bacterial phyla and 699 genera were identified, distributed as 125 genera from 8 phyla and 319 genera from 10 phyla shared by all the planting bases and all the tissues, respectively. The predominant Proteobacteria varied from 71.81% (GZ) to 96.08% (YN), and Delftia (10.39–38.42%), Burkholderia (2.71–15.98%), Escherichia/Shigella (4.90–25.12%), Pseudomonas (2.68–30.72%) and Sphingomonas (1.83–2.05%) dominated in four planting bases. Pseudomonas (17.94–22.06%), Escherichia/Shigella (6.59–11.59%), Delftia (9.65–22.14%) and Burkholderia (3.12–11.05%) dominated in all the tissues. According to Meta-nifH sequencing, 4 phyla and 45 genera were identified, while 17 genera and 24 genera from 4 phyla were shared by all the planting bases and all the tissues, respectively. Burkholderia and Bradyrhizobium were the most popular in the planting bases, followed by Methylovirgula and Mesorhizobium. Mesorhizobium was the most popular in different tissues, followed by Beijerinckia, Xanthobacter, and Burkholderia. Among the genera, 39 were completely overlapped with the results based on the 16S rRNA gene. In conclusion, abundant bacteria and diazotrophs were identified in common in different tissues of D. catenatum from five planting bases, which might play a great role in the supply of nutrients such as nitrogen. The exact abundance of phylum and genus on the different tissues from different planting bases need deeper sequencing with more samples. PMID:28931073

  16. Comparative effectiveness of different Rhizobium sp. for improving growth and yield of maize (Zea mays L.

    Ijaz Mehboob, Zahir Ahmad Zahir, Muhammad Arshad, Muhammad Khalid

    2012-05-01

    Full Text Available During the last couple of decades, it has been demonstrated that rhizobia can associate with roots of non-legumes also without forming true nodules, and can promote their growth by using one or more of the direct or indirect mechanisms of actions. This work examines the growth and yield responses of maize to inoculation with different species of rhizobia, isolated from the root nodules of chickpea (Cicer arietinum L., lentil (Lens culinaris M. and mung bean (Vigna radiata L. in pots and fields. Twenty isolates of rhizobia were isolated from root nodules each of mung bean, lentil and chickpea and were screened under axenic conditions. On the basis of their promising performance under axenic conditions, nine most efficient isolates (three from each legume host were selected, characterized and further evaluated for their growth promoting activities by conducting pot and field experiments. Results of pot experiment revealed that maximum increase in grain yield, 1000 grain weight, N, P and K uptake (up to 47.89, 54.52, 73.46, 84.66 and 59.19% by CRI28, respectively, over un-inoculated control was produced by the isolate of Mesorhizobium ciceri. Whereas, maximum improvement in rest of the parameters was caused by the isolates of Rhizobium phaseoli (i.e. fresh biomass, straw yield and root length up to 36.30% by A18, 25.46% by S6 and 81.89% by A18, respectively over un-inoculated control. Rhizobium leguminosarum isolates came out to be the least effective among the species tested. Similarly, all the selected isolates improved the growth and yield attributing parameters in fields as well but with varying capacity compared with un-inoculated control. The selected isolates of Mesorhizobium ciceri and Rhizobium phaseoli again remained superior compared to the isolates of Rhizobium leguminosarum under field conditions. The results of this study imply that rhizobium species had potential to promote growth and yield of maize but this technology should be

  17. Microvirga vignae sp. nov., a root nodule symbiotic bacterium isolated from cowpea grown in semi-arid Brazil.

    Radl, Viviane; Simões-Araújo, Jean Luiz; Leite, Jakson; Passos, Samuel Ribeiro; Martins, Lindete Míria Vieira; Xavier, Gustavo Ribeiro; Rumjanek, Norma Gouvêa; Baldani, José Ivo; Zilli, Jerri Edson

    2014-03-01

    16S rRNA gene sequence analysis of eight strains (BR 3299(T), BR 3296, BR 10192, BR 10193, BR 10194, BR 10195, BR 10196 and BR 10197) isolated from nodules of cowpea collected from a semi-arid region of Brazil showed 97 % similarity to sequences of recently described rhizobial species of the genus Microvirga. Phylogenetic analyses of four housekeeping genes (gyrB, recA, dnaK and rpoB), DNA-DNA relatedness and AFLP further indicated that these strains belong to a novel species within the genus Microvirga. Our data support the hypothesis that genes related to nitrogen fixation were obtained via horizontal gene transfer, as sequences of nifH genes were very similar to those found in members of the genera Rhizobium and Mesorhizobium, which are not immediate relatives of the genus Microvirga, as shown by 16S rRNA gene sequence analysis. Phenotypic traits, such as host range and carbon utilization, differentiate the novel strains from the most closely related species, Microvirga lotononidis, Microvirga zambiensis and Microvirga lupini. Therefore, these symbiotic nitrogen-fixing bacteria are proposed to be representatives of a novel species, for which the name Microvirga vignae sp. nov. is suggested. The type strain is BR3299(T) ( = HAMBI 3457(T)).

  18. Identification of symbiotic nitrogen-fixing bacteria from three African leguminous trees in Gorongosa National Park.

    Teixeira, Helena; Rodríguez-Echeverría, Susana

    2016-07-01

    The symbiosis between leguminous plants and symbiotic nitrogen-fixing bacteria is a key component of terrestrial ecosystems. Woody legumes are well represented in tropical African forests but despite their ecological and socio-economic importance, they have been little studied for this symbiosis. In this study, we examined the identity and diversity of symbiotic-nitrogen fixing bacteria associated with Acacia xanthophloea, Faidherbia albida and Albizia versicolor in the Gorongosa National Park (GNP) in Mozambique. To the best of our knowledge, this is the first report on the identity of symbiotic-nitrogen fixing bacteria in this region. 166 isolates were obtained and subjected to molecular identification. BOX-A1R PCR was used to discriminate different bacterial isolates and PCR-sequencing of 16S rDNA, and two housekeeping genes, glnII and recA, was used to identify the obtained bacteria. The gene nifH was also analyzed to assess the symbiotic capacity of the obtained bacteria. All isolates from F. albida and Al. versicolor belonged to the Bradyrhizobium genus whereas isolates from Ac. xanthophloea clustered with Mesorhizobium, Rhizobium or Ensifer strains. Soil chemical analysis revealed significant differences between the soils occupied by the three studied species. Thus, we found a clear delimitation in the rhizobial communities and soils associated with Ac. xanthophloea, F. albida and Al. versicolor, and higher rhizobial diversity for Ac. xanthophloea than previously reported. Copyright © 2016 Elsevier GmbH. All rights reserved.

  19. Crystallization and preliminary X-ray analysis of AAMS amidohydrolase, the final enzyme in degradation pathway I of pyridoxine

    Kobayashi, Jun; Yoshida, Hiromi; Chu, Huy Nhat; Yoshikane, Yu; Kamitori, Shigehiro; Yagi, Toshiharu

    2009-01-01

    Recombinant α-(N-acetylaminomethylene)succinic acid amidohydrolase from M. loti MAFF303099 was crystallized and diffraction data were collected at 2.7 Å resolution. α-(N-Acetylaminomethylene)succinic acid (AAMS) amidohydrolase from Mesorhizobium loti MAFF303099, which is involved in a degradation pathway of vitamin B 6 and catalyzes the degradation of AAMS to acetic acid, ammonia, carbon dioxide and succinic semialdehyde, has been overexpressed in Escherichia coli. To elucidate the reaction mechanism based on the tertiary structure, the recombinant enzyme was purified and crystallized by the sitting-drop vapour-diffusion method using PEG 8000 as precipitant. A crystal of the enzyme belonged to the monoclinic space group C2, with unit-cell parameters a = 393.2, b = 58.3, c = 98.9 Å, β = 103.4°, and diffraction data were collected to 2.7 Å resolution. The V M value and calculation of the self-rotation function suggested that three dimers with a threefold symmetry were possibly present in the asymmetric unit

  20. Impact of the energy crop Jatropha curcas L. on the composition of rhizobial populations nodulating cowpea (Vigna unguiculata L.) and acacia (Acacia seyal L.).

    Dieng, Amadou; Duponnois, Robin; Floury, Antoine; Laguerre, Gisèle; Ndoye, Ibrahima; Baudoin, Ezékiel

    2015-03-01

    Jatropha curcas, a Euphorbiaceae species that produces many toxicants, is increasingly planted as an agrofuel plant in Senegal. The purpose of this study was to determine whether soil priming induced by J. curcas monoculture could alter the rhizobial populations that nodulate cowpea and acacia, two locally widespread legumes. Soil samples were transferred into a greenhouse from three fields previously cultivated with Jatropha for 1, 2, and 15 years, and the two trap legumes were grown in them. Control soil samples were also taken from adjacent Jatropha-fallow plots. Both legumes tended to develop fewer but larger nodules when grown in Jatropha soils. Nearly all the nifH sequences amplified from nodule DNA were affiliated to the Bradyrhizobium genus. Only sequences from Acacia seyal nodules grown in the most recent Jatropha plantation were related to the Mesorhizobium genus, which was much a more conventional finding on A. seyal than the unexpected Bradyrhizobium genus. Apart from this particular case, only minor differences were found in the respective compositions of Jatropha soil versus control soil rhizobial populations. Lastly, the structure of these rhizobial populations was systematically imbalanced owing to the overwhelming dominance of a very small number of nifH genotypes, some of which were identical across soil types or even sites. Despite these weak and sparse effects on rhizobial diversity, future investigations should focus on the characterization of the nitrogen-fixing abilities of the predominant rhizobial strains. Copyright © 2014 Elsevier GmbH. All rights reserved.

  1. Genomic analyses of metal resistance genes in three plant growth promoting bacteria of legume plants in Northwest mine tailings, China.

    Xie, Pin; Hao, Xiuli; Herzberg, Martin; Luo, Yantao; Nies, Dietrich H; Wei, Gehong

    2015-01-01

    To better understand the diversity of metal resistance genetic determinant from microbes that survived at metal tailings in northwest of China, a highly elevated level of heavy metal containing region, genomic analyses was conducted using genome sequence of three native metal-resistant plant growth promoting bacteria (PGPB). It shows that: Mesorhizobium amorphae CCNWGS0123 contains metal transporters from P-type ATPase, CDF (Cation Diffusion Facilitator), HupE/UreJ and CHR (chromate ion transporter) family involved in copper, zinc, nickel as well as chromate resistance and homeostasis. Meanwhile, the putative CopA/CueO system is expected to mediate copper resistance in Sinorhizobium meliloti CCNWSX0020 while ZntA transporter, assisted with putative CzcD, determines zinc tolerance in Agrobacterium tumefaciens CCNWGS0286. The greenhouse experiment provides the consistent evidence of the plant growth promoting effects of these microbes on their hosts by nitrogen fixation and/or indoleacetic acid (IAA) secretion, indicating a potential in-site phytoremediation usage in the mining tailing regions of China. Copyright © 2014. Published by Elsevier B.V.

  2. Glycoconjugate Oxime Formation Catalyzed at Neutral pH: Mechanistic Insights and Applications of 1,4-Diaminobenzene as a Superior Catalyst for Complex Carbohydrates.

    Østergaard, Mads; Christensen, Niels Johan; Hjuler, Christian T; Jensen, Knud J; Thygesen, Mikkel B

    2018-04-18

    The reaction of unprotected carbohydrates with aminooxy reagents to provide oximes is a key method for the construction of glycoconjugates. Aniline and derivatives serve as organocatalysts for the formation of oximes from simple aldehydes, and we have previously reported that aniline also catalyzes the formation of oximes from the more complex aldehydes, carbohydrates. Here, we present a comprehensive study of the effect of aniline analogues on the formation of carbohydrate oximes and related glycoconjugates depending on organocatalyst structure, pH, nucleophile, and carbohydrate, covering more than 150 different reaction conditions. The observed superiority of the 1,4-diaminobenzene (PDA) catalyst at neutral pH is rationalized by NMR analyses and DFT studies of reaction intermediates. Carbohydrate oxime formation at pH 7 is demonstrated by the formation of a bioactive glycoconjugate from a labile, decorated octasaccharide originating from exopolysaccharides of the soil bacterium Mesorhizobium loti. This study of glycoconjugate formation includes the first direct comparison of aniline-catalyzed reaction rates and equilibrium constants for different classes of nucleophiles, including primary oxyamines, secondary N-alkyl oxyamines, as well as aryl and arylsulfonyl hydrazides. We identified 1,4-diaminobenzene as a superior catalyst for the construction of oxime-linked glycoconjugates under mild conditions.

  3. Nematode grazing promotes bacterial community dynamics in soil at the aggregate level.

    Jiang, Yuji; Liu, Manqiang; Zhang, Jiabao; Chen, Yan; Chen, Xiaoyun; Chen, Lijun; Li, Huixin; Zhang, Xue-Xian; Sun, Bo

    2017-12-01

    Nematode predation has important roles in determining bacterial community composition and dynamics, but the extent of the effects remains largely rudimentary, particularly in natural environment settings. Here, we investigated the complex microbial-microfaunal interactions in the rhizosphere of maize grown in red soils, which were derived from four long-term fertilization regimes. Root-free rhizosphere soil samples were separated into three aggregate fractions whereby the abundance and community composition were examined for nematode and total bacterial communities. A functional group of alkaline phosphomonoesterase (ALP) producing bacteria was included to test the hypothesis that nematode grazing may significantly affect specific bacteria-mediated ecological functions, that is, organic phosphate cycling in soil. Results of correlation analysis, structural equation modeling and interaction networks combined with laboratory microcosm experiments consistently indicated that bacterivorous nematodes enhanced bacterial diversity, and the abundance of bacterivores was positively correlated with bacterial biomass, including ALP-producing bacterial abundance. Significantly, such effects were more pronounced in large macroaggregates than in microaggregates. There was a positive correlation between the most dominant bacterivores Protorhabditis and the ALP-producing keystone 'species' Mesorhizobium. Taken together, these findings implicate important roles of nematodes in stimulating bacterial dynamics in a spatially dependent manner.

  4. Sequential induction of three recombination directionality factors directs assembly of tripartite integrative and conjugative elements.

    Timothy L Haskett

    2018-03-01

    Full Text Available Tripartite integrative and conjugative elements (ICE3 are a novel form of ICE that exist as three separate DNA regions integrated within the genomes of Mesorhizobium spp. Prior to conjugative transfer the three ICE3 regions of M. ciceri WSM1271 ICEMcSym1271 combine and excise to form a single circular element. This assembly requires three coordinated recombination events involving three site-specific recombinases IntS, IntG and IntM. Here, we demonstrate that three excisionases-or recombination directionality factors-RdfS, RdfG and RdfM are required for ICE3 excision. Transcriptome sequencing revealed that expression of ICE3 transfer and conjugation genes was induced by quorum sensing. Quorum sensing activated expression of rdfS, and in turn RdfS stimulated transcription of both rdfG and rdfM. Therefore, RdfS acts as a "master controller" of ICE3 assembly and excision. The dependence of all three excisive reactions on RdfS ensures that ICE3 excision occurs via a stepwise sequence of recombination events that avoids splitting the chromosome into a non-viable configuration. These discoveries expose a surprisingly simple control system guiding molecular assembly of these novel and complex mobile genetic elements and highlight the diverse and critical functions of excisionase proteins in control of horizontal gene transfer.

  5. Sequential induction of three recombination directionality factors directs assembly of tripartite integrative and conjugative elements.

    Haskett, Timothy L; Terpolilli, Jason J; Ramachandran, Vinoy K; Verdonk, Callum J; Poole, Phillip S; O'Hara, Graham W; Ramsay, Joshua P

    2018-03-01

    Tripartite integrative and conjugative elements (ICE3) are a novel form of ICE that exist as three separate DNA regions integrated within the genomes of Mesorhizobium spp. Prior to conjugative transfer the three ICE3 regions of M. ciceri WSM1271 ICEMcSym1271 combine and excise to form a single circular element. This assembly requires three coordinated recombination events involving three site-specific recombinases IntS, IntG and IntM. Here, we demonstrate that three excisionases-or recombination directionality factors-RdfS, RdfG and RdfM are required for ICE3 excision. Transcriptome sequencing revealed that expression of ICE3 transfer and conjugation genes was induced by quorum sensing. Quorum sensing activated expression of rdfS, and in turn RdfS stimulated transcription of both rdfG and rdfM. Therefore, RdfS acts as a "master controller" of ICE3 assembly and excision. The dependence of all three excisive reactions on RdfS ensures that ICE3 excision occurs via a stepwise sequence of recombination events that avoids splitting the chromosome into a non-viable configuration. These discoveries expose a surprisingly simple control system guiding molecular assembly of these novel and complex mobile genetic elements and highlight the diverse and critical functions of excisionase proteins in control of horizontal gene transfer.

  6. The effect of pseudo-microgravity on the symbiosis of plants and microorganisms

    Tomita-Yokotani, Kaori; Maki, Asano; Aoki, Toshio; Tamura, Kenji; Wada, Hidenori; Hashimoto, Hirofumi; Yamashita, Masamichi

    The symbiosis of plants and microorganisms is important to conduct agriculture under space environment. However, we have less knowledge on whether this kind of symbiosis can be established under space condition. We examined the functional compounds responsible to symbiosis between rhizobiaum and Lotus japonicus as a model of symbiotic combination. The existence of the substances for their symbiosis, some flavonoids, have already been known from the study of gene expression, but the detail structures have not yet been elucidated. Pseudomicrogravity was generated by the 3D-clinorotation. Twenty flavonoids were found in the extracts of 16 days plants of Lotus japonicus grown under the normal gravity by HPLC. Content of two flavonoids among them was affected by the infection of Mesorhizobium loti to them. It has a possibility that the two flavonoids were key substances for their combination process. The productions of those flavonoids were confirmed also under the pseudo-microgravity. The amount of one flavonoid was increased by both infection of rhizobium and exposure to the normal and pseudo-micro gravity. Chemical species of these flavonoids were identified by LC- ESI/MS and spectroscopic analysis. To show the effects of pseudo-microgravity on the gene expression, enzymic activities related to the functional compounds are evaluated after the rhizobial infection.

  7. Taxonomically Different Co-Microsymbionts of a Relict Legume, Oxytropis popoviana, Have Complementary Sets of Symbiotic Genes and Together Increase the Efficiency of Plant Nodulation.

    Safronova, Vera I; Belimov, Andrey A; Sazanova, Anna L; Chirak, Elizaveta R; Verkhozina, Alla V; Kuznetsova, Irina G; Andronov, Evgeny E; Puhalsky, Jan V; Tikhonovich, Igor A

    2018-06-20

    Ten rhizobial strains were isolated from root nodules of a relict legume Oxytropis popoviana Peschkova. For identification of the isolates, sequencing of rrs, the internal transcribed spacer region, and housekeeping genes recA, glnII, and rpoB was used. Nine fast-growing isolates were Mesorhizobium-related; eight strains were identified as M. japonicum and one isolate belonged to M. kowhaii. The only slow-growing isolate was identified as a Bradyrhizobium sp. Two strains, M. japonicum Opo-242 and Bradyrhizobium sp. strain Opo-243, were isolated from the same nodule. Symbiotic genes of these isolates were searched throughout the whole-genome sequences. The common nodABC genes and other symbiotic genes required for plant nodulation and nitrogen fixation were present in the isolate Opo-242. Strain Opo-243 did not contain the principal nod, nif, and fix genes; however, five genes (nodP, nodQ, nifL, nolK, and noeL) affecting the specificity of plant-rhizobia interactions but absent in isolate Opo-242 were detected. Strain Opo-243 could not induce nodules but significantly accelerated the root nodule formation after coinoculation with isolate Opo-242. Thus, we demonstrated that taxonomically different strains of the archaic symbiotic system can be co-microsymbionts infecting the same nodule and promoting the nodulation process due to complementary sets of symbiotic genes.

  8. A Legume Genetic Framework Controls Infection of Nodules by Symbiotic and Endophytic Bacteria

    Zgadzaj, Rafal; James, Euan K.; Kelly, Simon; Kawaharada, Yasuyuki; de Jonge, Nadieh; Jensen, Dorthe B.; Madsen, Lene H.; Radutoiu, Simona

    2015-01-01

    Legumes have an intrinsic capacity to accommodate both symbiotic and endophytic bacteria within root nodules. For the symbionts, a complex genetic mechanism that allows mutual recognition and plant infection has emerged from genetic studies under axenic conditions. In contrast, little is known about the mechanisms controlling the endophytic infection. Here we investigate the contribution of both the host and the symbiotic microbe to endophyte infection and development of mixed colonised nodules in Lotus japonicus. We found that infection threads initiated by Mesorhizobium loti, the natural symbiont of Lotus, can selectively guide endophytic bacteria towards nodule primordia, where competent strains multiply and colonise the nodule together with the nitrogen-fixing symbiotic partner. Further co-inoculation studies with the competent coloniser, Rhizobium mesosinicum strain KAW12, show that endophytic nodule infection depends on functional and efficient M. loti-driven Nod factor signalling. KAW12 exopolysaccharide (EPS) enabled endophyte nodule infection whilst compatible M. loti EPS restricted it. Analysis of plant mutants that control different stages of the symbiotic infection showed that both symbiont and endophyte accommodation within nodules is under host genetic control. This demonstrates that when legume plants are exposed to complex communities they selectively regulate access and accommodation of bacteria occupying this specialized environmental niche, the root nodule. PMID:26042417

  9. Rhizobial characterization in revegetated areas after bauxite mining

    Wardsson Lustrino Borges

    2016-06-01

    Full Text Available Abstract Little is known regarding how the increased diversity of nitrogen-fixing bacteria contributes to the productivity and diversity of plants in complex communities. However, some authors have shown that the presence of a diverse group of nodulating bacteria is required for different plant species to coexist. A better understanding of the plant symbiotic organism diversity role in natural ecosystems can be extremely useful to define recovery strategies of environments that were degraded by human activities. This study used ARDRA, BOX-PCR fingerprinting and sequencing of the 16S rDNA gene to assess the diversity of root nodule nitrogen-fixing bacteria in former bauxite mining areas that were replanted in 1981, 1985, 1993, 1998, 2004 and 2006 and in a native forest. Among the 12 isolates for which the 16S rDNA gene was partially sequenced, eight, three and one isolate(s presented similarity with sequences of the genera Bradyrhizobium, Rhizobium and Mesorhizobium, respectively. The richness, Shannon and evenness indices were the highest in the area that was replanted the earliest (1981 and the lowest in the area that was replanted most recently (2006.

  10. Rhizobial characterization in revegetated areas after bauxite mining.

    Borges, Wardsson Lustrino; Prin, Yves; Ducousso, Marc; Le Roux, Christine; de Faria, Sergio Miana

    2016-01-01

    Little is known regarding how the increased diversity of nitrogen-fixing bacteria contributes to the productivity and diversity of plants in complex communities. However, some authors have shown that the presence of a diverse group of nodulating bacteria is required for different plant species to coexist. A better understanding of the plant symbiotic organism diversity role in natural ecosystems can be extremely useful to define recovery strategies of environments that were degraded by human activities. This study used ARDRA, BOX-PCR fingerprinting and sequencing of the 16S rDNA gene to assess the diversity of root nodule nitrogen-fixing bacteria in former bauxite mining areas that were replanted in 1981, 1985, 1993, 1998, 2004 and 2006 and in a native forest. Among the 12 isolates for which the 16S rDNA gene was partially sequenced, eight, three and one isolate(s) presented similarity with sequences of the genera Bradyrhizobium, Rhizobium and Mesorhizobium, respectively. The richness, Shannon and evenness indices were the highest in the area that was replanted the earliest (1981) and the lowest in the area that was replanted most recently (2006). Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  11. Alkalinity of Lanzarote soils is a factor shaping rhizobial populations with Sinorhizobium meliloti being the predominant microsymbiont of Lotus lancerottensis.

    León-Barrios, Milagros; Pérez-Yépez, Juan; Dorta, Paola; Garrido, Ana; Jiménez, Concepción

    2017-04-01

    Lotus lancerottensis is an endemic species that grows widely throughout Lanzarote Island (Canary Is.). Characterization of 48 strains isolated from root nodules of plants growing in soils from eleven locations on the island showed that 38 isolates (79.1%) belonged to the species Sinorhizobium meliloti, whereas only six belonged to Mesorhizobium sp., the more common microsymbionts for the Lotus. Other genotypes containing only one isolate were classified as Pararhizobium sp., Sinorhizobium sp., Phyllobacterium sp. and Bradyrhizobium-like. Strains of S. meliloti were distributed along the island and, in most of the localities they were exclusive or major microsymbionts of L. lancerottensis. Phylogeny of the nodulation nodC gene placed the S. meliloti strains within symbiovar lancerottense and the mesorhizobial strains with the symbiovar loti. Although strains from both symbiovars produced effective N 2 -fixing nodules, S. meliloti symbiovar lancerottense was clearly the predominant microsymbiont of L. lancerottensis. This fact correlated with the better adaptation of strains of this species to the alkaline soils of Lanzarote, as in vitro characterization showed that while the mesorhizobial strains were inhibited by alkaline pH, S. meliloti strains grew well at pH 9. Copyright © 2017 Elsevier GmbH. All rights reserved.

  12. Genetic diversity of symbiotic Paraburkholderia species isolated from nodules of Mimosa pudica (L.) and Phaseolus vulgaris (L.) grown in soils of the Brazilian Atlantic Forest (Mata Atlântica).

    Dall'Agnol, Rebeca Fuzinatto; Bournaud, Caroline; de Faria, Sérgio Miana; Béna, Gilles; Moulin, Lionel; Hungria, Mariangela

    2017-04-01

    Some species of the genus Paraburkholderia that are able to nodulate and fix nitrogen in symbiosis with legumes are called β-rhizobia and represent a group of ecological and biotechnological importance. We used Mimosa pudica and Phaseolus vulgaris to trap 427 rhizobial isolates from rhizospheric soil of Mimoseae trees in the Brazilian Atlantic Forest. Eighty-four representative strains were selected according to the 16S rRNA haplotypes and taxonomically characterized using a concatenated 16S rRNA-recA phylogeny. Most strains were assembled in the genus Paraburkholderia, including Paraburkholderia sabiae and Pa. nodosa. Mesorhizobium (α-rhizobia) and Cupriavidus (β-rhizobia) were also isolated, but in smaller proportions. Multilocus sequence analysis and BOX-PCR analyses indicated that six clusters of Paraburkholderia represent potential new species. In the phylogenetic analysis of the nodC gene, the majority of the strains were positioned in the same groups as in the 16S rRNA-recA tree, indicative of stability and vertical inheritance, but we also identified horizontal transfer of nodC in Pa. sabiae. All α- and β-rhizobial species were trapped by both legumes, although preferences of the host plants for specific rhizobial species have been observed. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. Caracterização de rizóbios isolados de Jacatupé cultivado em solo salino no Estado de Pernanbuco, Brasil Characterization of isolated rhizobia from Pachyrhyzus erosus L. cultivated in saline soil of the State of Pernambuco, Brazil

    Ana Dolores Santiago de Freitas

    2007-01-01

    Full Text Available Pesquisas sobre a biodiversidade microbiológica de solos salinos envolvem a busca por genótipos tolerantes a esse tipo de estresse ambiental. Dados genotípicos correlacionados às características morfológicas, fisiológicas e bioquímicas de bactérias fornecem informações importantes para sua identificação e agrupamento. Este trabalho objetivou caracterizar rizóbios provenientes de solos salinos, do Agreste e Sertão de Pernambuco, utilizando jacatupé (Pachyrhizus erosus L. Urban como planta-isca. Os testes foram efetuados em meio YMA e as características culturais observadas em 24 isolados foram as seguintes: mudança de pH, tempo de crescimento, transparência, forma, borda, produção de exopolissacarídeo das colônias e resistência à salinidade. Os testes moleculares utilizando análise por PCR (reação em cadeia da polimerase por meio de seqüências repetitivas de DNA amplificadas com o primer BOX envolveram 13 isolados. Os resultados revelaram alta diversidade fenotípica e genotípica entre os isolados nativos. As características culturais e genéticas desses isolados foram comparados com 19 estirpes de referência. Os isolados NFB746 e NFB747 tiveram alta semelhança entre si e também com as estirpes Rhizobium sp. NGR234 (BR2406 e Mesorhizobium ciceri USDA3383 (BR521. O isolado NFB742, possivelmente, era da mesma espécie de M. ciceri (BR521. Com relação ao isolado NFB741, a semelhança com as bactérias Rhizobium tropici IIA CFN299T (BR10016 e Sinorhizobium terangue USDA4894 (BR527 foi de 87%. Os demais isolados, praticamente, formaram grupos independentes quando comparados com as estirpes de referência. Os resultados foram de grande relevância para diagnosticar novas espécies de rizóbios nativos altamente tolerantes a estresses ambientais.Investigation on microbiological biodiversity in the saline soils involves searching for tolerant genotypes to this type of emvironmental stress. Genotypic data associated to

  14. Mechanisms of physiological adjustment of N2 fixation in Cicer arietinum L. (chickpea) during early stages of water deficit: single or multi-factor controls.

    Nasr Esfahani, Maryam; Sulieman, Saad; Schulze, Joachim; Yamaguchi-Shinozaki, Kazuko; Shinozaki, Kazuo; Tran, Lam-Son Phan

    2014-09-01

    Drought negatively impacts symbiotic nitrogen fixation (SNF) in Cicer arietinum L. (chickpea), thereby limiting yield potential. Understanding how drought affects chickpea nodulation will enable the development of strategies to biotechnologically engineer chickpea varieties with enhanced SNF under drought conditions. By analyzing carbon and nitrogen metabolism, we studied the mechanisms of physiological adjustment of nitrogen fixation in chickpea plants nodulated with Mesorhizobium ciceri during both drought stress and subsequent recovery. The nitrogenase activity, levels of several key carbon (in nodules) and nitrogen (in both nodules and leaves) metabolites and antioxidant compounds, as well as the activity of related nodule enzymes were examined in M. ciceri-inoculated chickpea plants under early drought stress and subsequent recovery. Results indicated that drought reduced nitrogenase activity, and that this was associated with a reduced expression of the nifK gene. Furthermore, drought stress promoted an accumulation of amino acids, mainly asparagine in nodules (but not in leaves), and caused a cell redox imbalance in nodules. An accumulation of organic acids, especially malate, in nodules, which coincided with the decline of nodulated root respiration, was also observed under drought stress. Taken together, our findings indicate that reduced nitrogenase activity occurring at early stages of drought stress involves, at least, the inhibition of respiration, nitrogen accumulation and an imbalance in cell redox status in nodules. The results of this study demonstrate the potential that the genetic engineering-based improvement of SNF efficiency could be applied to reduce the impact of drought on the productivity of chickpea, and perhaps other legume crops. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.

  15. High diversity of nitrogen-fixing bacteria in upper reaches of Heihe River, Northwestern China

    Tai, X. S.; Mao, W. L.; Liu, G. X.; Chen, T.; Zhang, W.; Wu, X. K.; Long, H. Z.; Zhang, B. G.

    2013-03-01

    Vegetation plays a key role to water conservation in southern Qilian Mountains (Northwestern China), the upper reaches of Heihe River. Nitrogen-fixing bacteria are crucial for vegetation protection because they can supply plants with nitrogen source. Nevertheless, little is known about nitrogen-fixing bacteria in this region. In present study, nifH gene clone libraries were established for detecting the difference of nitrogen-fixing bacterial communities between Potentilla parvifolia shrub and Carex alrofusca meadow in the southern Qilian Mountains. All the identified nitrogen-fixing bacterial clones belonged to Proteobacteria. At the genus level, the Azospirillum sp. was only detected in shrub soil while Thiocapsa sp., Derxiasp., Ectothiorhodospira sp., Mesorhizobium sp., Klebsiella sp., Ensifer sp., Methylocella sp. and Peseudomonas sp. were just detected in meadow soil. Shannon-Wiener index of nifH gene ranged from 1.5 to 2.8 and was higher in meadow soil than shrub soil. Contrarily, the nifH gene copies and CFUs of cultured nitrogen-fixing bacteria ranged from 0.4 × 107 to 6.9 × 107 copies g-1 soil and 0.97 × 106 to 12.78 × 106 g-1 soil, respectively. Furthermore, both of them were lower in meadow soil than shrub soil. Statistical analysis revealed that diversity and copies of nifH gene mostly correlated with aboveground biomass in shrub soil. In meadow soil, nifH gene diversity was principally affected by altitude while copies did by soil available K.

  16. Structural, functional, and evolutionary analysis of moeZ, a gene encoding an enzyme required for the synthesis of the Pseudomonas metabolite, pyridine-2,6-bis(thiocarboxylic acid

    Crawford Ronald L

    2002-04-01

    Full Text Available Abstract Background Pyridine-2,6-bis(thiocarboxylic acid (pdtc is a small secreted metabolite that has a high affinity for transition metals, increases iron uptake efficiency by 20% in Pseudomonas stutzeri, has the ability to reduce both soluble and mineral forms of iron, and has antimicrobial activity towards several species of bacteria. Six GenBank sequences code for proteins similar in structure to MoeZ, a P. stutzeri protein necessary for the synthesis of pdtc. Results Analysis of sequences similar to P. stutzeri MoeZ revealed that it is a member of a superfamily consisting of related but structurally distinct proteins that are members of pathways involved in the transfer of sulfur-containing moieties to metabolites. Members of this family of enzymes are referred to here as MoeB, MoeBR, MoeZ, and MoeZdR. MoeB, the molybdopterin synthase activating enzyme in the molybdopterin cofactor biosynthesis pathway, is the most characterized protein from this family. Remarkably, lengths of greater than 73% nucleic acid homology ranging from 35 to 486 bp exist between Pseudomonas stutzeri moeZ and genomic sequences found in some Mycobacterium, Mesorhizobium, Pseudomonas, Streptomyces, and cyanobacteria species. Conclusions The phylogenetic relationship among moeZ sequences suggests that P. stutzeri may have acquired moeZ through lateral gene transfer from a donor more closely related to mycobacteria and cyanobacteria than to proteobacteria. The importance of this relationship lies in the fact that pdtc, the product of the P. stutzeri pathway that includes moeZ, has an impressive set of capabilities, some of which could make it a potent pathogenicity factor.

  17. Comparative symbiotic plasmid analysis indicates that symbiosis gene ancestor type affects plasmid genetic evolution.

    Wang, X; Zhao, L; Zhang, L; Wu, Y; Chou, M; Wei, G

    2018-07-01

    Rhizobial symbiotic plasmids play vital roles in mutualistic symbiosis with legume plants by executing the functions of nodulation and nitrogen fixation. To explore the gene composition and genetic constitution of rhizobial symbiotic plasmids, comparison analyses of 24 rhizobial symbiotic plasmids derived from four rhizobial genera was carried out. Results illustrated that rhizobial symbiotic plasmids had higher proportion of functional genes participating in amino acid transport and metabolism, replication; recombination and repair; carbohydrate transport and metabolism; energy production and conversion and transcription. Mesorhizobium amorphae CCNWGS0123 symbiotic plasmid - pM0123d had similar gene composition with pR899b and pSNGR234a. All symbiotic plasmids shared 13 orthologous genes, including five nod and eight nif/fix genes which participate in the rhizobia-legume symbiosis process. These plasmids contained nod genes from four ancestors and fix genes from six ancestors. The ancestral type of pM0123d nod genes was similar with that of Rhizobium etli plasmids, while the ancestral type of pM0123d fix genes was same as that of pM7653Rb. The phylogenetic trees constructed based on nodCIJ and fixABC displayed different topological structures mainly due to nodCIJ and fixABC ancestral type discordance. The study presents valuable insights into mosaic structures and the evolution of rhizobial symbiotic plasmids. This study compared 24 rhizobial symbiotic plasmids that included four genera and 11 species, illuminating the functional gene composition and symbiosis gene ancestor types of symbiotic plasmids from higher taxonomy. It provides valuable insights into mosaic structures and the evolution of symbiotic plasmids. © 2018 The Society for Applied Microbiology.

  18. The symbiotic biofilm of Sinorhizobium fredii SMH12, necessary for successful colonization and symbiosis of Glycine max cv Osumi, is regulated by Quorum Sensing systems and inducing flavonoids via NodD1.

    Francisco Pérez-Montaño

    Full Text Available Bacterial surface components, especially exopolysaccharides, in combination with bacterial Quorum Sensing signals are crucial for the formation of biofilms in most species studied so far. Biofilm formation allows soil bacteria to colonize their surrounding habitat and survive common environmental stresses such as desiccation and nutrient limitation. This mode of life is often essential for survival in bacteria of the genera Mesorhizobium, Sinorhizobium, Bradyrhizobium, and Rhizobium. The role of biofilm formation in symbiosis has been investigated in detail for Sinorhizobium meliloti and Bradyrhizobium japonicum. However, for S. fredii this process has not been studied. In this work we have demonstrated that biofilm formation is crucial for an optimal root colonization and symbiosis between S. fredii SMH12 and Glycine max cv Osumi. In this bacterium, nod-gene inducing flavonoids and the NodD1 protein are required for the transition of the biofilm structure from monolayer to microcolony. Quorum Sensing systems are also required for the full development of both types of biofilms. In fact, both the nodD1 mutant and the lactonase strain (the lactonase enzyme prevents AHL accumulation are defective in soybean root colonization. The impairment of the lactonase strain in its colonization ability leads to a decrease in the symbiotic parameters. Interestingly, NodD1 together with flavonoids activates certain quorum sensing systems implicit in the development of the symbiotic biofilm. Thus, S. fredii SMH12 by means of a unique key molecule, the flavonoid, efficiently forms biofilm, colonizes the legume roots and activates the synthesis of Nod factors, required for successfully symbiosis.

  19. Actinorhizal Alder Phytostabilization Alters Microbial Community Dynamics in Gold Mine Waste Rock from Northern Quebec: A Greenhouse Study.

    Katrina L Callender

    Full Text Available Phytotechnologies are rapidly replacing conventional ex-situ remediation techniques as they have the added benefit of restoring aesthetic value, important in the reclamation of mine sites. Alders are pioneer species that can tolerate and proliferate in nutrient-poor, contaminated environments, largely due to symbiotic root associations with the N2-fixing bacteria, Frankia and ectomycorrhizal (ECM fungi. In this study, we investigated the growth of two Frankia-inoculated (actinorhizal alder species, A. crispa and A. glutinosa, in gold mine waste rock from northern Quebec. Alder species had similar survival rates and positively impacted soil quality and physico-chemical properties in similar ways, restoring soil pH to neutrality and reducing extractable metals up to two-fold, while not hyperaccumulating them into above-ground plant biomass. A. glutinosa outperformed A. crispa in terms of growth, as estimated by the seedling volume index (SVI, and root length. Pyrosequencing of the bacterial 16S rRNA gene for bacteria and the ribosomal internal transcribed spacer (ITS region for fungi provided a comprehensive, direct characterization of microbial communities in gold mine waste rock and fine tailings. Plant- and treatment-specific shifts in soil microbial community compositions were observed in planted mine residues. Shannon diversity and the abundance of microbes involved in key ecosystem processes such as contaminant degradation (Sphingomonas, Sphingobium and Pseudomonas, metal sequestration (Brevundimonas and Caulobacter and N2-fixation (Azotobacter, Mesorhizobium, Rhizobium and Pseudomonas increased over time, i.e., as plants established in mine waste rock. Acetate mineralization and most probable number (MPN assays showed that revegetation positively stimulated both bulk and rhizosphere communities, increasing microbial density (biomass increase of 2 orders of magnitude and mineralization (five-fold. Genomic techniques proved useful in

  20. Dissecting the Root Nodule Transcriptome of Chickpea (Cicer arietinum L..

    Chandra Kant

    Full Text Available A hallmark trait of chickpea (Cicer arietinum L., like other legumes, is the capability to convert atmospheric nitrogen (N2 into ammonia (NH3 in symbiotic association with Mesorhizobium ciceri. However, the complexity of molecular networks associated with the dynamics of nodule development in chickpea need to be analyzed in depth. Hence, in order to gain insights into the chickpea nodule development, the transcriptomes of nodules at early, middle and late stages of development were sequenced using the Roche 454 platform. This generated 490.84 Mb sequence data comprising 1,360,251 reads which were assembled into 83,405 unigenes. Transcripts were annotated using Gene Ontology (GO, Cluster of Orthologous Groups (COG and Kyoto Encyclopedia of Genes and Genomes (KEGG metabolic pathways analysis. Differential expression analysis revealed that a total of 3760 transcripts were differentially expressed in at least one of three stages, whereas 935, 117 and 2707 transcripts were found to be differentially expressed in the early, middle and late stages of nodule development respectively. MapMan analysis revealed enrichment of metabolic pathways such as transport, protein synthesis, signaling and carbohydrate metabolism during root nodulation. Transcription factors were predicted and analyzed for their differential expression during nodule development. Putative nodule specific transcripts were identified and enriched for GO categories using BiNGO which revealed many categories to be enriched during nodule development, including transcription regulators and transporters. Further, the assembled transcriptome was also used to mine for genic SSR markers. In conclusion, this study will help in enriching the transcriptomic resources implicated in understanding of root nodulation events in chickpea.

  1. Dissecting the Root Nodule Transcriptome of Chickpea (Cicer arietinum L.).

    Kant, Chandra; Pradhan, Seema; Bhatia, Sabhyata

    2016-01-01

    A hallmark trait of chickpea (Cicer arietinum L.), like other legumes, is the capability to convert atmospheric nitrogen (N2) into ammonia (NH3) in symbiotic association with Mesorhizobium ciceri. However, the complexity of molecular networks associated with the dynamics of nodule development in chickpea need to be analyzed in depth. Hence, in order to gain insights into the chickpea nodule development, the transcriptomes of nodules at early, middle and late stages of development were sequenced using the Roche 454 platform. This generated 490.84 Mb sequence data comprising 1,360,251 reads which were assembled into 83,405 unigenes. Transcripts were annotated using Gene Ontology (GO), Cluster of Orthologous Groups (COG) and Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathways analysis. Differential expression analysis revealed that a total of 3760 transcripts were differentially expressed in at least one of three stages, whereas 935, 117 and 2707 transcripts were found to be differentially expressed in the early, middle and late stages of nodule development respectively. MapMan analysis revealed enrichment of metabolic pathways such as transport, protein synthesis, signaling and carbohydrate metabolism during root nodulation. Transcription factors were predicted and analyzed for their differential expression during nodule development. Putative nodule specific transcripts were identified and enriched for GO categories using BiNGO which revealed many categories to be enriched during nodule development, including transcription regulators and transporters. Further, the assembled transcriptome was also used to mine for genic SSR markers. In conclusion, this study will help in enriching the transcriptomic resources implicated in understanding of root nodulation events in chickpea.

  2. Isolation and growth characteristics of an EDTA-degrading member of the alpha-subclass of Proteobacteria.

    Weilenmann, Hans-Ueli; Engeli, Barbara; Bucheli-Witschel, Margarete; Egli, Thomas

    2004-10-01

    A Gram-negative, ethylenediaminetetraacetic acid (EDTA)-degrading bacterium (deposited at the German Culture Collection as strain DSM 9103) utilising EDTA as the only source of carbon, energy and nitrogen was isolated from a mixed EDTA-degrading population that was originally enriched in a column system from a mixture of activated sludge and soil. Chemotaxonomic analysis of quinones, polar lipids and fatty acids allowed allocation of the isolate to the alpha-subclass of Proteobacteria. 16S rDNA sequencing and phylogenetic analysis revealed highest similarity to the Mesorhizobium genus followed by the Aminobacter genus. However, the EDTA-degrading strain apparently forms a new branch within the Phyllobacteriaceae/Mesorhizobia family. Growth of the strain was rather slow not only on EDTA (micro(max) = 0.05 h(-1)) but also on other substrates. Classical substrate utilisation testing in batch culture suggested a quite restricted carbon source spectrum with only lactate, glutamate, and complexing agents chemically related to EDTA (nitrilotriacetate, iminodiacetate and ethylenediaminedisuccinate) supporting growth. However, when EDTA-limited continuous cultures of strain DSM 9103 were pulsed with fumarate, succinate, glucose or acetate, these substrates were assimilated immediately. Apparently, the strain can use a broader spectrum than indicated by traditional substrate testing techniques. The EDTA species CaEDTA and MgEDTA served as growth substrates of the strain because in the mineral medium employed EDTA was predicted to be mainly present in the form of these two complexes. The bacterium was not able to degrade Fe3+-complexed EDTA.

  3. Responses to the contributors

    Garrett Barden

    2011-09-01

    Full Text Available A set of responses to the papers on Garrett Barden's and Tim Murphy's book Law and Justice in Community (Oxford: OUP, 2010 published in this special issue of Nordicum-Mediterraneum.

  4. High diversity of nitrogen-fixing bacteria in the upper reaches of the Heihe River, northwestern China

    X. S. Tai

    2013-08-01

    Full Text Available Vegetation plays a key role in water conservation in the southern Qilian Mountains (northwestern China, located in the upper reaches of the Heihe River. Nitrogen-fixing bacteria are crucial for the protection of the nitrogen supply for vegetation in the region. In the present study, nifH gene clone libraries were established to determine differences between the nitrogen-fixing bacterial communities of the Potentilla parvifolia shrubland and the Carex alrofusca meadow in the southern Qilian Mountains. All of the identified nitrogen-fixing bacterial clones belonged to the Proteobacteria. At the genus level, Azospirillum was only detected in the shrubland soil, while Thiocapsa, Derxia, Ectothiorhodospira, Mesorhizobium, Klebsiella, Ensifer, Methylocella and Pseudomonas were only detected in the meadow soil. The phylogenetic tree was divided into five lineages: lineages I, II and III mainly contained nifH sequences obtained from the meadow soils, while lineage IV was mainly composed of nifH sequences obtained from the shrubland soils. The Shannon–Wiener index of the nifH genes ranged from 1.5 to 2.8 and was higher in the meadow soils than in the shrubland soils. Based on these analyses of diversity and phylogeny, the plant species were hypothesised to influence N cycling by enhancing the fitness of certain nitrogen-fixing taxa. The number of nifH gene copies and colony-forming units (CFUs of the cultured nitrogen-fixing bacteria were lower in the meadow soils than in the shrubland soils, ranging from 0.4 × 107 to 6.9 × 107 copies g−1 soil and 0.97 × 106 to 12.78 × 106 g−1 soil, respectively. Redundancy analysis (RDA revealed that the diversity and number of the nifH gene copies were primarily correlated with aboveground biomass in the shrubland soil. In the meadow soil, nifH gene diversity was most affected by altitude, while copy number was most impacted by soil-available K. These results suggest that the nitrogen-fixing bacterial

  5. High diversity of nitrogen-fixing bacteria in the upper reaches of the Heihe River, northwestern China

    Tai, X. S.; Mao, W. L.; Liu, G. X.; Chen, T.; Zhang, W.; Wu, X. K.; Long, H. Z.; Zhang, B. G.; Zhang, Y.

    2013-08-01

    Vegetation plays a key role in water conservation in the southern Qilian Mountains (northwestern China), located in the upper reaches of the Heihe River. Nitrogen-fixing bacteria are crucial for the protection of the nitrogen supply for vegetation in the region. In the present study, nifH gene clone libraries were established to determine differences between the nitrogen-fixing bacterial communities of the Potentilla parvifolia shrubland and the Carex alrofusca meadow in the southern Qilian Mountains. All of the identified nitrogen-fixing bacterial clones belonged to the Proteobacteria. At the genus level, Azospirillum was only detected in the shrubland soil, while Thiocapsa, Derxia, Ectothiorhodospira, Mesorhizobium, Klebsiella, Ensifer, Methylocella and Pseudomonas were only detected in the meadow soil. The phylogenetic tree was divided into five lineages: lineages I, II and III mainly contained nifH sequences obtained from the meadow soils, while lineage IV was mainly composed of nifH sequences obtained from the shrubland soils. The Shannon-Wiener index of the nifH genes ranged from 1.5 to 2.8 and was higher in the meadow soils than in the shrubland soils. Based on these analyses of diversity and phylogeny, the plant species were hypothesised to influence N cycling by enhancing the fitness of certain nitrogen-fixing taxa. The number of nifH gene copies and colony-forming units (CFUs) of the cultured nitrogen-fixing bacteria were lower in the meadow soils than in the shrubland soils, ranging from 0.4 × 107 to 6.9 × 107 copies g-1 soil and 0.97 × 106 to 12.78 × 106 g-1 soil, respectively. Redundancy analysis (RDA) revealed that the diversity and number of the nifH gene copies were primarily correlated with aboveground biomass in the shrubland soil. In the meadow soil, nifH gene diversity was most affected by altitude, while copy number was most impacted by soil-available K. These results suggest that the nitrogen-fixing bacterial communities beneath Potentilla

  6. Differential response of kabuli and desi chickpea genotypes toward inoculation with PGPR in different soils

    Imran, Asma; Mirza, Muhammad S.; Shah, Tariq M.; Malik, Kauser A.; Hafeez, Fauzia Y.

    2015-01-01

    Pakistan is among top three chickpea producing countries but the crop is usually grown on marginal lands without irrigation and fertilizer application which significantly hampers its yield. Soil fertility and inoculation with beneficial rhizobacteria play a key role in nodulation and yield of legumes. Four kabuli and six desi chickpea genotypes were, therefore, evaluated for inoculation response with IAA-producing Ochrobactrum ciceri Ca-34T and nitrogen fixing Mesorhizobium ciceri TAL-1148 in single and co-inoculation in two soils. The soil type 1 was previously unplanted marginal soil having low organic matter, P and N contents compared to soil type 2 which was a fertile routinely legume-cultivated soil. The effect of soil fertility status was pronounced and fertile soil on average, produced 31% more nodules, 62% more biomass and 111% grain yield than marginal soil. Inoculation either with O. ciceri alone or its co-inoculation with M. ciceri produced on average higher nodules (42%), biomass (31%), grains yield (64%) and harvest index (72%) in both chickpea genotypes over non-inoculated controls in both soils. Soil 1 showed maximum relative effectiveness of Ca-34T inoculation for kabuli genotypes while soil 2 showed for desi genotypes except B8/02. Desi genotype B8/02 in soil type 1 and Pb-2008 in soil type 2 showed significant yield increase as compared to respective un-inoculated controls. Across bacterial inoculation treatments, grain yield was positively correlated to growth and yield contributing parameters (r = 0.294* to 0.838*** for desi and r = 0.388* to 0.857** for kabuli). PCA and CAT-PCA analyses clearly showed a site-specific response of genotype x bacterial inoculation. Furthermore, the inoculated bacterial strains were able to persist in the rhizosphere showing colonization on root and within nodules. Present study shows that plant growth promoting rhizobacteria (PGPR) inoculation should be integrated with national chickpea breading program in

  7. Co-existence of Rhizobia and Diverse Non-rhizobial Bacteria in the Rhizosphere and Nodules of Dalbergia odorifera Seedlings Inoculated with Bradyrhizobium elkanii, Rhizobium multihospitium–Like and Burkholderia pyrrocinia–Like Strains

    Junkun Lu

    2017-11-01

    Full Text Available Rhizobia induce root nodules and fix atmospheric N2 for most legume species in exchange for carbon. However, the diverse endophytic non-rhizobial bacteria in legume nodules that co-exist with rhizobia are often ignored because they are difficult to cultivate using routine cultivation approaches. To enhance our understanding of the incidence and diversity of legume–bacteria associations, a high-throughput sequencing analysis of bacterial 16S rRNA genes was used to examine the bacterial community in the rhizospheres and root nodules of Dalbergia odorifera seedlings that were uninoculated or inoculated with Bradyrhizobium elkanii H255, Rhizobium multihospitium–like HT221, or Burkholderia pyrrocinia–like H022238, in two growth media (nitrogen [N]-supplied soil or N-omitted potting mix. Seedlings inoculated with Bradyrhizobium had significantly more nodules than seedlings in the other inoculation conditions, regardless of growth media. Using the 15N natural abundance method, it was shown that the inoculated plants had significantly higher N2 fixation efficiency (48–57% and specific nodule activity [269–313 μg N mg−1 of dry weight (dwt nodule] compared to the uninoculated plants (203 μg N mg−1 dwt nodule. The 16S rRNA gene analysis showed that there was generally a higher bacterial diversity in the rhizosphere than in the nodules in the corresponding condition. Both rhizobial inoculation and media status significantly altered the bacterial communities in the rhizospheres and nodules (P < 0.05, with the exception of the inoculated soil rhizospheres. Regarding non-rhizobial bacteria, three genera, i.e., Lactococcus, Bacillus, and Pseudomonas, were consistently enriched in the rhizosphere and Bradyrhizobium, Chloroplast norank (which belongs to Cyanobacteria, and Lactococcus were commonly found in the nodules. In contrast, common rhizobial genera (including Rhizobium, Mesorhizobium, and Burkholderia were only present in the nodules at low

  8. COREMIC: a web-tool to search for a niche associated CORE MICrobiome

    Richard R. Rodrigues

    2018-02-01

    Full Text Available Microbial diversity on earth is extraordinary, and soils alone harbor thousands of species per gram of soil. Understanding how this diversity is sorted and selected into habitat niches is a major focus of ecology and biotechnology, but remains only vaguely understood. A systems-biology approach was used to mine information from databases to show how it can be used to answer questions related to the core microbiome of habitat-microbe relationships. By making use of the burgeoning growth of information from databases, our tool “COREMIC” meets a great need in the search for understanding niche partitioning and habitat-function relationships. The work is unique, furthermore, because it provides a user-friendly statistically robust web-tool (http://coremic2.appspot.com or http://core-mic.com, developed using Google App Engine, to help in the process of database mining to identify the “core microbiome” associated with a given habitat. A case study is presented using data from 31 switchgrass rhizosphere community habitats across a diverse set of soil and sampling environments. The methodology utilizes an outgroup of 28 non-switchgrass (other grasses and forbs to identify a core switchgrass microbiome. Even across a diverse set of soils (five environments, and conservative statistical criteria (presence in more than 90% samples and FDR q-val <0.05% for Fisher’s exact test a core set of bacteria associated with switchgrass was observed. These included, among others, closely related taxa from Lysobacter spp., Mesorhizobium spp, and Chitinophagaceae. These bacteria have been shown to have functions related to the production of bacterial and fungal antibiotics and plant growth promotion. COREMIC can be used as a hypothesis generating or confirmatory tool that shows great potential for identifying taxa that may be important to the functioning of a habitat (e.g. host plant. The case study, in conclusion, shows that COREMIC can identify key habitat

  9. Quelques noddees sur l’ecologie de la vedetation des dunes et sur la fonction de l’enraciment dans l’edification de dunes a la Cote Mediterraneenne de la France. I

    Boterenbrood, A.J.; Donsellaar-Ten Bokkel Huinink, van W.A.E.; Donselaar, van J.

    1956-01-01

    Dans la végétation des dunes du Languedoc J. BRAUN-BLANQUET (1952) distingue trois associations, à savoir; 1) l’Agropyretum mediterraneum parmi et sur les premières dunes basses; 2) l’Ammophiletum arundinaceae sur les dunes plus hautes; et 3) le Crucianelletum maritimae dans les dépressions et en

  10. Herman Salton, Arctic Host, Icy Visit: China and Falun Gong Face Off in Iceland (Saarbrücken: LAP Lambert Academic Publishing, 2010

    Aníta Einarsdóttir

    2012-03-01

    Full Text Available Due to the controversial nature of the book reviewed, Nordicum-Mediterraneum is taking the unusual step of seeking two reviews from contrasting perspectives. The first is a review by an Icelandic citizen and the second by a Chinese citizen who is resident in Iceland.

  11. Crisis and Crisis Scenarios

    Larsen, Øjvind

    2016-01-01

    This special issue of Nordicum-Mediterraneum contains select proceedings from the third meeting of the Nordic Summer University research circle called “Crisis and Crisis Scenarios: Normativity, Possibilities and Dilemmas”, held April 9th — 12th, 2015 at the Lysebu Conference Centre in Oslo, Norway....... The circle’s research program runs from 2014 to 2016 and is aimed at examining the concept of crisis as it is used today in academia and public discussion. In this collection of papers from the symposium we present some of the different ways in which the topic of the study group was addressed....

  12. “Crisis and Crisis Scenarios: Normativity, Possibilities and Dilemmas” (Lysebu Conference Centre in Oslo, Norway, April 9th — 12th, 2015

    Øjvind Larsen

    2016-03-01

    Full Text Available This special issue of Nordicum-Mediterraneum contains select proceedings from the third meeting of the Nordic Summer University research circle called “Crisis and Crisis Scenarios: Normativity, Possibilities and Dilemmas”, held April 9th — 12th, 2015 at the Lysebu Conference Centre in Oslo, Norway. The circle’s research program runs from 2014 to 2016 and is aimed at examining the concept of crisis as it is used today in academia and public discussion. In this collection of papers from the symposium we present some of the different ways in which the topic of the study group was addressed.

  13. Beyond the Cold-War Reprise of the Arctic Super-Powers. Decoding the Structural Meaning of the Ukrainian Crisis

    John McMurtry

    2015-03-01

    Full Text Available The “Ukraine crisis” repeats a script as old as the Cold War, of which the Arctic was one of its main theatres and that, as suggested by Irina Zhilina in her 2013 study about NATO in the far north for issue 8(1 of Nordicum-Mediterraneum, could regain such a role, were frictions between East and West to resurface. And they have resurfaced. The ongoing Cold-War-like narrative vis-à-vis Ukraine features rising attacks by corporate states and media on the traditional whipping boy of Russia. As usual, “escalating the crisis” is the other Arctic super-power: the US. As usual, alarm about “increasing lawless aggression” is projection of US policy itself.

  14. Northern Steps of EU Enlargement: The Impact of “Cohesion” Policies on Iceland’s Accession Process

    Adriana Di Stefano

    2011-03-01

    Full Text Available This paper focuses on the EU accession process of Iceland, reading the latest northern steps of EU enlargement under a “cohesion” perspective, i.e., through the lens of the cohesion “theory”, namely the method resulting from interactions of the general principles of subsidiarity and cooperation or partnership. From the Mediterranean to the Arctic, the territorial dimension of cohesion policies, as grounded in different EU policies, plays different roles and meets a wide range of economic and social needs. By implementing Nordicum-Mediterraneum analogies, a cohesion-minded EU enlargement approach requires the overall reframing of territorial-based policies and a better allocation of shared responsibilities at the more efficient level of governance.

  15. Expression analysis of cellulose synthase and main cytoskeletal protein genes in flax (Linum usitatissimum L.).

    Galinousky, Dmitry; Padvitski, Tsimafei; Bayer, Galina; Pirko, Yaroslav; Pydiura, Nikolay; Anisimova, Natallia; Nikitinskaya, Tatyana; Khotyleva, Liubov; Yemets, Alla; Kilchevsky, Aleksandr; Blume, Yaroslav

    2017-08-09

    Fiber flax is an important source of natural fiber and a comprehensive model for the plant fiber biogenesis studies. Cellulose-synthase (CesA) and cytoskeletal genes are known to be important for the cell wall biogenesis in general and for the biogenesis of flax fibers in particular. Currently, knowledge about activity of these genes during the plant growth is limited. In this study, we have investigated flax fiber biogenesis by measuring expression of CesA and cytoskeletal genes at two stages of the flax development (seedlings and stems at the rapid growth stage) in several flax subspecies (elongatum, mediterraneum, crepitans). RT-qPCR has been used to quantify the expression of LusСesA1, LusСesA4, LusСesA7, LusСesA6, Actin, and α-Tubulin genes in plant samples. We report that CesA genes responsible for the secondary cell wall synthesis (LusCesA4, LusCesA7) have different expression pattern compared with CesA genes responsible for the primary cell wall synthesis (LusCesA1, LusCesA6): an average expression of LusCesA4 and LusCesA7 genes is relatively high in seedlings and further increases in stems at the rapid growth stage, whereas an average expression of LusCesA1 and LusCesA6 genes decreases. Interestingly, LusCesA1 is the only studied gene with different expression dynamics between the flax subspecies: its expression decreases by 5.2-10.7 folds in elongatum and mediterraneum but does not change in crepitans subspecies when the rapid growth stage and seedlings are compared. The expression of cytoskeleton genes (coding actin and α-tubulin) is relatively stable and significantly higher than the expression of cellulose-synthase genes in all the studied samples. © 2017 International Federation for Cell Biology.

  16. Faunistic assemblages of a sublittoral coarse sand habitat of the northwestern Mediterranean

    Eva Pubill

    2011-02-01

    Full Text Available The sublittoral megabenthic assemblages of a northwestern Mediterranean coarse sandy beach exploited for the bivalve Callista chione were studied. The spatial and bathymetric variability of its distinctive faunal assemblages was characterised by quantitative sampling performed with a clam dredge. The taxa studied were Mollusca Bivalvia and Gastropoda, Crustacea Decapoda, Echinodermata and Pisces, which accounted for over 99% of the total biomass. Three well-differentiated species assemblages were identified: (1 assemblage MSS (Medium Sand Shallow in medium sand (D50=0.37 mm and shallow waters (mean depth =6.5 m, (2 assemblage CSS (Coarse Sand Shallow in coarse sand (D50=0.62 mm in shallow waters (mean depth =6.7 m, and (3 assemblage CSD (Coarse Sand Deep in coarse sand (D50=0.64 mm in deeper waters (mean depth =16.2 m. Assemblage MSS was characterised by the codominance of the bivalves Mactra stultorum and Acanthocardia tuberculata. C. chione was dominant in both density and biomass in assemblages CSS and CSD. The occurrence of the crab Thia scutellata also characterised assemblage CSS, whereas the occurrence of the sea urchin Echinocardium mediterraneum characterised assemblage CSD. A depth breaking point of around 10 m determined the discontinuity between assemblages CSS and CSD, which was related to the closure depth of the beaches in the study area. Species richness was highest in the coarse sand communities; however, Shannon-Wiener diversity and Pielou equitability indexes were higher in the shallow fine sand community.

  17. Formal Revision of the Alexandrium tamarense Species Complex (Dinophyceae) Taxonomy: The Introduction of Five Species with Emphasis on Molecular-based (rDNA) Classification

    John, Uwe; Litaker, R. Wayne; Montresor, Marina; Murray, Shauna; Brosnahan, Michael L.; Anderson, Donald M.

    2015-01-01

    The Alexandrium tamarense species complex is one of the most studied marine dinoflagellate groups due to its ecological, toxicological and economic importance. Several members of this complex produce saxitoxin and its congeners – potent neurotoxins that cause paralytic shellfish poisoning. Isolates from this complex are assigned to A. tamarense, A. fundyense, or A. catenella based on two main morphological characters: the ability to form chains and the presence/absence of a ventral pore between Plates 1′ and 4′. However, studies have shown that these characters are not consistent and/or distinctive. Further, phylogenies based on multiple regions in the rDNA operon indicate that the sequences from morphologically indistinguishable isolates partition into five clades. These clades were initially named based on their presumed geographic distribution, but recently were renamed as Groups I–V following the discovery of sympatry among some groups. In this study we present data on morphology, ITS/5.8S genetic distances, ITS2 compensatory base changes, mating incompatibilities, toxicity, the sxtA toxin synthesis gene, and rDNA phylogenies. All results were consistent with each group representing a distinct cryptic species. Accordingly, the groups were assigned species names as follows: Group I, A. fundyense; Group II, A. mediterraneum; Group III, A. tamarense; Group IV, A. pacificum; Group V, A. australiense. PMID:25460230

  18. Evaluation of fungicides to protect pruning wounds from Botryosphaeriaceae species infections on almond trees

    Diego OLMO

    2017-05-01

    Full Text Available In vitro efficacy of ten fungicides was evaluated against four Botryosphaeriaceae spp. (Diplodia seriata, Neofusicoccum luteum, N. mediterraneum and N. parvum associated with branch cankers on almond trees. Cyproconazole, pyraclostrobin, tebuconazole, and thiophanate-methyl were effective for the inhibition of mycelial growth of most of these fungi. An experiment on 3-year-old almond trees evaluated boscalid, mancozeb, thiophanate-methyl, pyraclostrobin and tebuconazole for preventative ability against infections caused by the four pathogens. Five months after pruning and fungicide application, lesion length measurements and isolation percentages showed no significant differences among the four pathogens after they were inoculated onto the trees, and also between the two inoculation times tested (1 or 7 d after fungicide application. Thiophanate-methyl was the most effective fungicide, resulting in the shortest lesion lengths and the lowest isolation percentages from artificially inoculated pruning wounds. This chemical is therefore a candidate for inclusion in integrated disease management, to protect pruning wounds from infections caused by species of Botryosphaeriaceae. This study represents the first approach to development of chemical control strategies for the management of canker diseases caused by Botryosphaeriaceae fungi on almond trees.