Genetic Diversity among
            <i>Rhizobium leguminosarum</i>
            bv. Trifolii Strains Revealed by Allozyme and Restriction Fragment Length Polymorphism Analyses

Demezas, David H.; Reardon, Terry; Watson, John M.; Gibson, A. H.

doi:10.1128/aem.57.12.3489-3495.1991

Cited by 55 publications

(26 citation statements)

References 43 publications

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“…1991). Two cloned chromosomal DNA fragments were used as probes: recombinant plasmid pRtlOl3, which contains a repeated DNA sequence and cosmid pIM178, which contains part of an ATPase structural gene (Demezas et al 1991) (see Fig. 1).…”

Section: Restriction Fragment Length Polymorphism Analysismentioning

confidence: 99%

Diversity and genetic structure of a natural population of Rhizobium leguminosarum bv. trifolii isolated from Trifolium subterraneum L.

et al. 1995

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A collection of 121 isolates of Rhizobium leguminosarum biovar (bv.) trifolii was obtained from root nodules of Trifolium subterraneum L. (subclover) plants growing in an established pasture. The collection consisted of a single isolate from each of 18 plants sampled from seven microplots. The following year, a further 28 and 27 isolates were collected from the first and seventh sampling points, respectively. Analysis of restriction fragment length polymorphisms (RFLPs) of both chromosomal and Sym (symbiotic) plasmid DNA and multilocus enzyme electrophoresis (MLEE) were used to assess the diversity, genetic relationships and structure of this population. Symbiotic effectiveness tests were used to examine the symbiotic phenotype of each isolate collected in the first year. Analysis of RFLPs of the first year isolates revealed 13 chromosomal types and 25 Sym plasmid types. Similar Sym plasmid types were grouped into 14 families containing 1–6 members. No new chromosomal types and six new Sym plasmid types were detected in the second year. The symbiotic effectiveness of the first year isolates of the same Sym plasmid type was similar. Significant differences in symbiotic effectiveness were detected between different Sym plasmid types in the same plasmid family. Representative isolates of each chromosomal type Sym plasmid type identified in the first year were analysed using multilocus enzyme electrophoresis. Mean genetic diversity per locus was high (0.559). Enzyme electrophoresis revealed 17 electrophoretic types (ETs). Ouster analysis of the enzyme data revealed large genetic diversity amongst the ETs. Strong linkage disequilibrium was observed for the population as a whole, i.e. clonal population structure, but significantly less disequilibrium was observed among a cluster of ETs suggesting that recombination occurred between ETs within the cluster. Our results revealed that a population of naturally occurring isolates of Rhizobium leguminosarum bv. trifolii can be genetically diverse and support the possibility that recombination plays a role in generating new genotypes.

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Section: Restriction Fragment Length Polymorphism Analysismentioning

confidence: 99%

Diversity and genetic structure of a natural population of Rhizobium leguminosarum bv. trifolii isolated from Trifolium subterraneum L.

et al. 1995

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“…Moreover, the establishment of symbiosis is controlled by the abundance, viability and infectivity of natural populations of rhizobia (Bottomley, 1992). Different studies indicated that the genetic diversity of natural populations of rhizobia could also be affected by the site of origin and by host plant factors (Demezas et al, 1991;Paffetti et al, 1998;Carelli et al, 2000;Palmer & Young, 2000;Andronov et al, 2001;Bromfield et al, 2001;Zhang et al, 2001;Laguerre et al, 2003). The adaptation of the rhizobial populations to a particular environment not only affects the genetic structure of the population but it can also mould the phenotypic traits of the strains, a phenomenon particularly relevant for traits such as salt tolerance.…”

Section: Introductionmentioning

confidence: 99%

Diversity ofSinorhizobiumstrains nodulatingMedicago sativafrom different Iranian regions

Talebi¹,

Bahar²,

Saeidi³

et al. 2008

FEMS Microbiology Letters

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Alfalfa is believed to have originated in north-western Iran and has a long history of coexistence with its bacterial symbiont Sinorhizobium in soils of Iran. However, little is known about the diversity of Sinorhizobium strains nodulating Iranian alfalfa genotypes. In this study, Sinorhizobium populations were sampled from eight different Iranian sites using three cultivars of Medicago sativa as trap host plants. A total of 982 rhizobial strains were isolated and species were identified showing a large prevalence of Sinorhizobium meliloti over Sinorhizobium medicae. Analysis of salt tolerance demonstrated a great phenotypic diversity. The genetic diversity of the Sinorhizobium isolates was analysed using BOX-PCR and enterobacterial repetitive intergenic consensus (ERIC)-PCR. Patterns ofBOX-PCR fingerprinting were statistically analysed with AMOVA to evaluate the role of plant variety and site of origin in the genetic variance observed. Results indicated that most of the total molecular variance was attributable to divergence among strains isolated from different sites and cultivars (intrapopulation, strain-by-strain variance). Moreover, the analysis showed the presence of two geographic populations (west and northwest), indicating that the effect of the site of origin could be more relevant in shaping population genetic diversity than the effect of cultivar or individual plant.

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“…However, the conservative nature of the 16s rRNA genes limits the discriminatory power of the method for distinguishing closely related strains. T h e discrimination of rhizobial strains can be achieved by other molecular techniques such as classical RFLP, which is based on Southern hybridization (Demezas et al 1991), and also by a direct RFLP analysis of 16s rDNA amplificates (Armarger et al 1994;Laguerre et al 1994). However, discrimination of closely related strains by these methods requires the application of several probes and/or several restriction endonucleases.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Rhizobium ‘hedysari’ by RFLP analysis of PCR amplified rDNA and by genomic PCR fingerprinting

Selenska‐Pobell

Evguenieva‐Hackenberg

Radeva

et al. 1996

Journal of Applied Bacteriology

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The taxonomic and discriminatory power of RFLP analysis of PCR amplified parts of rhizobial rrn operons was compared to those of genomic PCR fingerprinting with arbitrary and repetitive primers. For this purpose, the two methods were applied for characterization of a group of bacterial isolates referred to as Rhizobium 'hedysari'. As outgroups, representatives of the family Rhizobiaceae, belonging to the Rhizobium galegae, Rhizobium meliloti, Rhizobium leguminosarum and Agrobacterium tumefaciens species were used. By the RFLP analysis of the PCR products corresponding to the variable 5'-half of the 23S rRNA gene and of the amplified spacer region between the 16S and 23S rRNA genes all Rh. 'hedysari' strains studied were tightly clustered together while the outgroups were placed in an outer position. The PCR products of the 3' end parts of the 23S rDNA did not show significant RFL polymorphism and no species differentiation on their basis was possible. In parallel, analysis of the same strains was performed by PCR amplification of their DNA with 19, 18 and 10 bp long arbitrary primers (AP-PCR) as well as with single primers corresponding to several bacterial repetitive sequences (rep-PCR). By both AP and rep-PCR an identification of every particular strain was achieved. In general, all primers provided taxonomic results that are in agreement with the species and group assignments based on the RFLP analysis of the rrn operons. On the basis of the results presented here it can be concluded that AP and rep-PCR are more informative and discriminative than rDNA and RFLP analysis of the rhizobial strains studied.

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Genetic Diversity among Rhizobium leguminosarum bv. Trifolii Strains Revealed by Allozyme and Restriction Fragment Length Polymorphism Analyses

Cited by 55 publications

References 43 publications

Diversity and genetic structure of a natural population of Rhizobium leguminosarum bv. trifolii isolated from Trifolium subterraneum L.

Diversity and genetic structure of a natural population of Rhizobium leguminosarum bv. trifolii isolated from Trifolium subterraneum L.

Diversity ofSinorhizobiumstrains nodulatingMedicago sativafrom different Iranian regions

Characterization of Rhizobium ‘hedysari’ by RFLP analysis of PCR amplified rDNA and by genomic PCR fingerprinting

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