Rhizobium population genetics: Effect of clover variety and inoculum dilution on the genetic diversity sampled from natural populations

Harrison, S P; Young, J. Peter W.; Jones, D. Gareth

doi:10.1007/bf02370682

Cited by 21 publications

(8 citation statements)

References 15 publications

(11 reference statements)

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“…If we had sampled loci that were more polymorphic, it is possible that we would have picked up differences in frequency reflecting site or host effects. There are some reports of differences in preference among T. repens cultivars (Russell and Jones, 1975; Roughley et al ., 1976; Jones and Hardarson, 1979), but in other cases there was little effect (Roughley et al ., 1976; Harrison et al ., 1987).…”

Section: Discussionmentioning

confidence: 99%

Direct amplification of nodD from community DNA reveals the genetic diversity of Rhizobium leguminosarum in soil

Zeze¹,

Mutch

Young³

2001

Environmental Microbiology

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Article:Zeze, A, Mutch, L A and Young, J P W orcid.org/0000-0001- 5259-4830 (2001) ReuseItems deposited in White Rose Research Online are protected by copyright, with all rights reserved unless indicated otherwise. They may be downloaded and/or printed for private study, or other acts as permitted by national copyright laws. The publisher or other rights holders may allow further reproduction and re-use of the full text version. This is indicated by the licence information on the White Rose Research Online record for the item. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. SummarySequences of nodD, a gene found only in rhizobia, were amplified from total community DNA isolated from a pasture soil. The polymerase chain reaction (PCR) primers used, Y5 and Y6, match nodD from Rhizobium leguminosarum biovar trifolii, R. leguminosarum biovar viciae and Sinorhizobium meliloti. The PCR product was cloned and yielded 68 clones that were identified by restriction pattern as derived from biovar trifolii [11 restriction fragment length polymorphism (RFLP) types] and 15 clones identified as viciae (seven RFLP types). These identifications were confirmed by sequencing. There were no clones related to S. meliloti nodD. For comparison, 122 strains were isolated from nodules of white clover (Trifolium repens) growing at the field site, and 134 from nodules on trap plants of T. repens inoculated with the soil. The nodule isolates were of four nodD RFLP types, with 77% being of a single type. All four of these patterns were also found among the clones from soil DNA, and the same type was the most abundant, although it made up only 34% of the trifoliilike clones. We conclude that clover selects specific genotypes from the available soil population, and that R. leguminosarum biovar trifolii was approximately five times more abundant than biovar viciae in this pasture soil, whereas S. meliloti was rare.

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Section: Discussionmentioning

confidence: 99%

Direct amplification of nodD from community DNA reveals the genetic diversity of Rhizobium leguminosarum in soil

Zeze¹,

Mutch

Young³

2001

Environmental Microbiology

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“…All isolates were examined by PAGE of three enzymes (Young, 1985;Harrison et al, 1987) : glucose-6-phosphate dehydrogenase (G6PD), superoxide dismutase (SOD) and P-galactosidase (BGAL). The alleles of each locus were labelled alphabetically with a single letter in order of descending PAGE mobility.…”

Section: Methodsmentioning

confidence: 99%

Rhizobium Population Genetics: Genetic Variation Within and Between Populations from Diverse Locations

1989

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Polyacrylamide gel electrophoresis (PAGE) of isoenzymes of chromosomal origin, and plasmid profile analyses, were used to investigate genetic variation within and between natural populations of Rhizobium leguminosarum biovar trifolii from diverse sources. PAGE showed that, within the biovar in general, relatively few alleles existed for the enzyme loci studied. There was a strong genetic disequilibrium between loci, suggesting that chromosomal recombination is rare. Both PAGE and plasmid profile analysis revealed differences in the degree of strain polymorphism at the sites examined. At sites which were acidic, improved (by liming) and neutral, strain variation was found to be low, intermediate and high, respectively.

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“…Similar to previous studies of agricultural systems, sym plasmid transfer was determined from the correlation between major genotypes at nodulation and nonsymbiotic loci. Both host plant species (23,28,35) and sampling location (36,37) are considered important in shaping genetic divergence of Rhizobium, so we used the unique strategy of sampling nodules of the same legume species across several sites to distinguish the effects of host plant and sampling location on the divergence of Rhizobium plasmid and chromosomal loci. In contrast to previous studies, we observed a strict correlation between genetic groups at symbiotic plasmid and chromosomal loci across several sampling locations and host plant species, which strongly argues for a surprising stability of sym plasmids within chromosomal lineages of native Rhizobium populations.…”

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Rhizobium gone native: Unexpected plasmid stability of indigenous Rhizobium leguminosarum

Wernegreen

Harding

Riley

1997

Proc. Natl. Acad. Sci. U.S.A.

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Lateral transfer of bacterial plasmids is thought to play an important role in microbial evolution and population dynamics. However, this assumption is based primarily on investigations of medically or agriculturally important bacterial species. To explore the role of lateral transfer in the evolution of bacterial systems not under intensive, human-mediated selection, we examined the association of genotypes at plasmid-encoded and chromosomal loci of native Rhizobium, the nitrogen-fixing symbiont of legumes. To this end, Rhizobium leguminosarum strains nodulating sympatric species of native Trifolium were characterized genetically at plasmid-encoded symbiotic (sym) regions (nodulation AB and nodulation CIJT loci) and a repeated chromosomal locus not involved in the symbiosis with legumes. Restriction fragment length polymorphism analysis was used to distinguish genetic groups at plasmid and chromosomal loci. The correlation between major sym and chromosomal genotypes and the distribution of genotypes across host plant species and sampling location were determined using 2 analysis. In contrast to findings of previous studies, a strict association existed between major sym plasmid and chromosomal genetic groups, suggesting a lack of successful sym plasmid transfer between major Rhizobium chromosomal types. These data indicate that previous observations of sym plasmid transfer in agricultural settings may seriously overestimate the rates of successful conjugation in systems not impacted by human activities. In addition, a nonrandom distribution of Rhizobium genotypes across host plant species and sampling site demonstrates the importance of both factors in shaping Rhizobium population dynamics.

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Rhizobium population genetics: Effect of clover variety and inoculum dilution on the genetic diversity sampled from natural populations

Cited by 21 publications

References 15 publications

Direct amplification of nodD from community DNA reveals the genetic diversity of Rhizobium leguminosarum in soil

Direct amplification of nodD from community DNA reveals the genetic diversity of Rhizobium leguminosarum in soil

Rhizobium Population Genetics: Genetic Variation Within and Between Populations from Diverse Locations

Rhizobium gone native: Unexpected plasmid stability of indigenous Rhizobium leguminosarum

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