Rhizobium Leguminosarum as a Model for Investigating Gene Transfer in Soil

Hirsch, P. R.; Spokes, J. R.

doi:10.1007/978-3-642-73419-9_2

Cited by 9 publications

(5 citation statements)

References 11 publications

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“…From several transposon mutants, RSM2004 was chosen as it had no apparent disruption of phenotype (apart from gaining the resistance genes carried by Tn5) and its symbiotic competence in plant infection tests, growth rate, and survival in laboratory culture was apparently identical to the parental strain. The absence of vector sequences was confirmed by the lack of homology to vector DNA probes [4]. The probe used to detect Tn5 in Rhizobium isolates was the plasmid pKan2.…”

Section: Bacterial Strains Methods and Probesmentioning

confidence: 99%

“…The inoculant strain RSM2004 was constructed to maximize the potential for detecting gene transfer, with the Tn5 marker inserted in a conjugative symbiotic plasmid known to transfer to a range of other rhizobia at relatively high frequencies, up to 10% of acceptor bacteria receiving the plasmid when crossed with RSM2004 [3]. Details of the construction of RSM2004 and a preliminary description of the field experiment have been reported [4].…”

Section: Introductionmentioning

confidence: 99%

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Survival and dispersion of genetically modified rhizobia in the field and genetic interactions with native strains

Hirsch

1994

FEMS Microbiology Ecology

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A genetically modified strain of the symbiotic nitrogen-fixing bacterium Rhizobium leguminosarum biovar viciae was used to inoculate a typical host, pea, and a control non-host cereal crop in the field. The inoculant was monitored for survival and spread from the site of application, and for genetic interactions with the native population. It could be identified by chromosomally located antibiotic resistance markers and additional markers conferred by the transposon Tn5 inserted on its conjugative symbiotic plasmid. These markers facilitated enumeration of the strain on selective agar, enabling survival and spread to be monitored over a six year period. Although culturable cell numbers dropped two to three orders of magnitude after the first year, subsequently they remained around 102 viable cells per g soil, even in subplots where only the non-host cereals had been grown. However, peas did give the inoculant a small survival advantage compared with non-hosts. Soil cultivation appeared to play a major role in inoculant dissemination from the site of application. Transfer of the Tn5 marker to other rhizobia could be monitored by screening for isolates with Tn5-encoded antibiotic resistance in the absence of the inoculant chromosomal markers. Over three years, more than 4000 pea root nodules were screened for indigenous rhizobia that had acquired the Tn5-marked symbiotic plasmid from the inoculant. None were detected, although overall about 2% of nodules contained the inoculant strain, and transfer of the Tn5-marked symbiotic plasmid to three out of four R. leguminosarum biovar viciae isolates from the field site could be demonstrated under laboratory conditions.

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Section: Bacterial Strains Methods and Probesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Survival and dispersion of genetically modified rhizobia in the field and genetic interactions with native strains

Hirsch

1994

FEMS Microbiology Ecology

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“…There are also possibilities in monitoring the survival of introduced micro-organisms under field conditions. Thus Hirsch & Spokes (1988) introduced into the field a Rhizobium sp. which had been previously selected for chromosomally-located resistance to two antibiotics followed by insertion of a DNA sequence conferring additional antibiotic resistances.…”

Section: Applications Of Molecular Biology To Soil Pollution Monitoringmentioning

confidence: 99%

The Potential of Microbiological Properties as Indicators in Soil Pollution Monitoring

Brookes

1993

Soil Monitoring

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“…This enabled detection of plasmid transfer, since TnS encodes neomycin resistance and provides a unique DNA sequence (Hirsch and Spokes, 1988).…”

Section: Introductionmentioning

confidence: 99%

The Release of Genetically Modified Microorganisms—REGEM 2

Stewart‐Tull¹,

Sussman²

1992

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Rhizobium Leguminosarum as a Model for Investigating Gene Transfer in Soil

Cited by 9 publications

References 11 publications

Survival and dispersion of genetically modified rhizobia in the field and genetic interactions with native strains

Survival and dispersion of genetically modified rhizobia in the field and genetic interactions with native strains

The Potential of Microbiological Properties as Indicators in Soil Pollution Monitoring

The Release of Genetically Modified Microorganisms—REGEM 2

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