Search results for "rhizobia"
showing 10 items of 33 documents
Vigna mungo, V. radiata and V. unguiculata plants sampled in different agronomical-ecological-climatic regions of India are nodulated by Bradyrhizobi…
2009
International audience; Vigna mungo, Vigna radiata and Vigna unguiculata are important legume crops cultivated in India, but little is known about the genetic resources in native rhizobia that nodulate these species. To identify these bacteria, a core collection of 76 slow-growing isolates was built from root nodules of V. mungo, V. radiata and V. unguiculata plants grown at different sites within three agro-ecological-climatic regions of India. The genetic diversity of the bacterial collection was assessed by restriction fragment length polymorphism (RFLP) analysis of PCR-amplified DNA fragments of the 16S–23S rDNA intergenic spacer (IGS) region, and the symbiotic genes nifH and nodC. One …
Plant phenology and genetic variability in root and nodule development strongly influence genetic structuring of Rhizobium leguminosarum biovar vicia…
2008
Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699; International audience; The symbiotic relationships between legumes and their nitrogen (N-2)-fixing bacterial partners (rhizobia) vary in effectiveness to promote plant growth according to both bacterial and legume genotype. To assess the selective effect of host plant on its microsymbionts, the influence of the pea (Pisum sativum) genotype on the relative nodulation success of Rhizobium leguminosarum biovar viciae (Rlv) genotypes from the soil populations during plant development h…
Biological nitrogen fixation for the 21st century
1998
The biodiversity of nitrogen-fixing organisms is huge. Taxonomic and phylogenetic research is needed to structure this diversity, to facilitate communication among scientists, and to increase our understanding of the evolution and biology of diazotrophs. Molecular tools for taxonomic and biodiversity studies of diazotrophic rhizobia, frankiae, cyanobacteria and bacilli are presented in sections 2 to 5. Sections 6 to 9 focus on problems with genus and species assignment.
Genetic Diversity of Rhizobia Isolated from the Legume Genera Astragalus, Oxytropis and Onobrychis
1998
The legume genera Astragalus and Oxytropis belong to the tribe Galegae. These legumes are common in Arctic and Temperate climatic zones. Previous studies based on cross-inoculation experiments and numerical taxonomy (Prevost et al., 1987; Novikova et al., 1993; 1994) suggested that the rhizobia associated with these legumes were closely related. Also the legume species Onobrychis viciifolia (sainfoin, tribe Hedysareae) was effectively nodulated by rhizobia isolated from Astragalus and Oxytropis spp. (Prevost et al., 1987). Rhizobia isolated from A. sinicus were classified in a new species, Mesorhizobium huakuii, (Chen et al., 1991; Jarvis et al., 1997). Other rhizobia from Astragalus and Ox…
Phylogenetic comparison of symbiotic (nodC and nifH) and 16S rRNA genes in strains of Rhizobium, Mesorhizobium and Bradyrhizobium isolated from Astra…
2000
Various studies reported different conclusions on the phylogenetic relationship between symbiotic (nod and nif) and chromosomal (16S rRNA) genes in rhizobia (Haukka et al, 1998). Some studies suggested that the phylogeny of nod genes could be related with the host plant (Ueda et al., 1995). In a previous study, rhizobia (44 isolates) from Astragalus, Oxytropis and Onobrychis pp have been classified into 14 distinct 16S rRNA gene types independently of their host plant and geographic origin. The majority of isolates were classified within the genus Mesorhizobium, and few within Rhizobium and Bradyrhizobium genera (Laguerre et al., 1997). The aim of the present study was to determine the dive…
Characterization of rhizobia nodulating chickpea in Tunisia
2001
Cent cinquante rhizobia nodulant le pois chiche (Cicer arietinum L.) ont ete isoles a partir de sols echantillonnes dans differentes regions de Tunisie. L'inoculation de la plante hote avec ces isolats montre une variabilite dans le temps d'apparition des premieres nodosites. Cinq isolats induisent des nodosites deux semaines apres inoculation alors que pour les 145 isolats restants les nodosites ne sont observees qu'apres au moins quatre semaines. L'etude par PCR/RFLP de l'ADNr 16S a permis de rattacher les isolats du premier groupe a l'espece Mesorhizobium mediterraneum et ceux du second groupe a l'espece Sinorhizobium medicae. La position taxonomique des isolats a ete confirmee par leurs…
New insights into the use of rhizobia to mitigate soil N2O emissions
2022
Agriculture is a major anthropogenic source of the greenhouse gas N2O, which is also involved in stratospheric ozone depletion. While the use of rhizobial inoculants has already been reported as an emerging option for mitigating soil N2O emissions, this study presents an in situ abatement of 70% of soil N2O emission using the strain nosZ+ G49 vs. nosZ− USDA138 in association with soybean. Therefore, we consider that the choice of the inoculant strain of a leguminous crop should take into account the capacity of strains to reduce nitrous oxide in addition to their N fixation capacity. This study also clearly suggests that this mitigation option could be considered not only for soybean but al…
Les symbioses fixatrices d'azote
2012
Les plantes dites "fixatrices symbiotiques d'azote", comme toutes les plantes, ont besoin d'azote, mais ont la propriété remarquable de pouvoir puiser cet élément à partir de l'atmosphère, tandis que les autres plantes cultivées doivent recevoir des engrais azotés. En fait, ce n’est pas la plante elle-même qui est capable de fixer l'azote de l'air, mais des bactéries spécifiques avec lesquelles elles vivent en association au niveau d'organes particuliers : les nodosités. C'est le cas de deux principaux groupes de plantes : les légumineuses (ou fabacées) qui s'associent avec les Rhizobia et des plantes appartenant à huit familles d'angiospermes (dites actinorhiziennes) qui s'associent avec l…
Response to salinity stress of Rhizobium leguminosarum bv. viciae strains in the presence of different legume host plants
2011
We investigated the effect of residual salts from the previous summer’s irrigation on two non-irrigated cover crops—broad bean and common vetch—and on their rhizobial symbiontics. Before sowing, seeds were inoculated with a salt-tolerant strain and a salt-sensitive strain of Rhizobium leguminosarum biovar viciae. An increase in the electrical conductivity of the saturated-soil extract from 2.0 dS m−1 to 6.0 dS m−1 caused a severe reduction of broad bean biomass, while growth of common vetch was almost unaffected by the salinity level. Our results clearly indicate that common vetch as a cover crop may increase the availability of nitrogen in soil more than broad bean also in saline environme…
Different species and symbiotic genotypes of field rhizobia can nodulate Phaseolus vulgaris in Tunisian soils.
2002
Abstract A collection of 160 isolates of rhizobia nodulating Phaseolus vulgaris in three geographical regions in Tunisia was characterized by restriction fragment length polymorphism analysis of polymerase chain reaction (PCR)-amplified 16S rDNA, nifH and nodC genes. Nine groups of rhizobia were delineated: Rhizobium gallicum biovar (bv.) gallicum, Rhizobium leguminosarum bv. phaseoli and bv. viciae, Rhizobium etli bv. phaseoli, Rhizobium giardinii bv. giardinii, and four groups related to species of the genus Sinorhizobium, Sinorhizobium meliloti, Sinorhizobium medicae and Sinorhizobium fredii. The most abundant rhizobial species were R. gallicum, R. etli, and R. leguminosarum encompassing…