Rhizobium Legume Symbiosis
Mostrando 13-24 de 52 artigos, teses e dissertações.
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13. MsPG3, a Medicago sativa polygalacturonase gene expressed during the alfalfa–Rhizobium meliloti interaction
Polygalacturonase (PG) is one of the most important enzymes associated with plant cell wall degradation. It has been proposed to participate in the early steps of the Rhizobium–legume interaction. We have identified two classes of cDNA fragments corresponding to two classes of PG genes in the Medicago genome. One of this class, represented by E2 in M. trun
The National Academy of Sciences.
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14. Cloning of the rpoD analog from Rhizobium etli: sigA of R. etli is growth phase regulated.
Rhizobium bacteria fix atmospheric nitrogen during symbiosis with legume plants only after bacterial division is arrested. The role of the major vegetative sigma factor, SigA, utilized by Rhizobium bacteria during symbiosis is unknown. By using PCR technology, a portion of the sigA gene corresponding to domain II was directly amplified from Rhizobium etli to
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15. Transient induction of a peroxidase gene in Medicago truncatula precedes infection by Rhizobium meliloti.
Although key determinative events of the Rhizobium-legume symbiosis are likely to precede bacterial infection, no plant genes have been identified that are expressed strongly prior to infection and nodule morphogenesis. A subtractive hybridization-polymerase chain reaction technique was used to enrich for genes induced during the early phases of the R. melil
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16. Effects of Boron on Rhizobium-Legume Cell-Surface Interactions and Nodule Development.
Boron (B) is an essential micronutrient for the development of nitrogen-fixing root nodules in pea (Pisum sativum). By using monoclonal antibodies that recognize specific glycoconjugate components implicated in legume root-nodule development, we investigated the effects of low B on the formation of infection threads and the colonization of pea nodules by Rhi
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17. A nod factor binding lectin with apyrase activity from legume roots
A lectin isolated from the roots of the legume, Dolichos biflorus, binds to Nod factors produced by rhizobial strains that nodulate this plant and has a deduced amino acid sequence with no significant homology to any lectin reported to date. This lectin also is an enzyme that catalyzes the hydrolysis of phosphoanhydride bonds of nucleoside di- and triphospha
The National Academy of Sciences.
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18. Population Densities of Rhizobium japonicum Strain 123 Estimated Directly in Soil and Rhizospheres †
Rhizobium japonicum serotype 123 was enumerated in soil and rhizospheres by fluorescent antibody techniques. Counting efficiency was estimated to be about 30%. Indigenous populations of strain 123 ranged from a few hundred to a few thousand per gram of field soil before planting. Rhizosphere effects from field-grown soybean plants were modest, reaching a max
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19. Aromatic aminotransferase activity and indoleacetic acid production in Rhizobium meliloti.
Bacterial indoleacetic acid (IAA) production, which has been proposed to play a role in the Rhizobium-legume symbiosis, is a poorly understood process. Previous data have suggested that IAA biosynthesis in Rhizobium meliloti can occur through an indolepyruvate intermediate derived from tryptophan by an aminotransferase activity. To further examine this biosy
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20. Comparison of DNA Polymerase of Rhizobium meliloti and Alfalfa Bacteroids 1
DNA dependent-DNA polymerase activity was established and partially purified from extracts of cultured Rhizobium meliloti, F-28, and nodule bacteroids (R. meliloti, F-28) of alfalfa plants (Medicago sativa). Polymerase activity in the partially purified fractions showed characteristic dependence on Mg2+, DNA, and a full complement of deoxyribonucleoside trip
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21. Subtraction hybridisation and shot-gun sequencing: a new approach to identify symbiotic loci.
Traditionally, new loci involved in the Rhizobium-legume symbiosis have been identified by transposon mutagenesis and/or complementation. Wide dispersal of the symbiotic loci in Rhizobium species NGR234, as well as the large number of potential host-plants to be screened, greatly reduces the efficiency of these techniques. As an alternate strategy designed t
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22. Alfalfa Root Flavonoid Production Is Nitrogen Regulated.
Flavonoids produced by legume roots are signal molecules acting both as chemoattractants and nod gene inducers for the symbiotic Rhizobium partner. Combined nitrogen inhibits the establishment of the symbiosis. To know whether nitrogen nutrition could act at the level of signal production, we have studied the expression of flavonoid biosynthetic genes as wel
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23. Localization of a Nod Factor-Binding Protein in Legume Roots and Factors Influencing Its Distribution and Expression1
The roots of the legume Dolichos biflorus contain a lectin/nucleotide phosphohydrolase (Db-LNP) that binds to the Nod factor signals produced by rhizobia that nodulate this plant. In this study we show that Db-LNP is differentially distributed along the surface of the root axis in a pattern that correlates with the zone of nodulation of the root. Db-LNP is p
American Society of Plant Physiologists.
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24. The Rhizobial hemA Gene Is Required for Symbiosis in Species with Deficient [delta]-Aminolevulinic Acid Uptake Activity.
Most rhizobial hemA mutants induce root nodules on their respective legume hosts that lack nitrogen fixation activity and leghemoglobin expression. However, a Bradyrhizobium japonicum hemA mutant elicits effective nodules on soybean, and we proposed previously that synthesis and uptake of the heme precursor [delta]-aminolevulinic acid (ALA) by the plant and