Plasmid transfer within and between serologically distinct strains of Rhizobium japonicum, using antibiotic resistance mutants and auxotrophs

Pilacinski, William P.; Schmidt, E. L.

doi:10.1128/jb.145.2.1025-1030.1981

Cited by 22 publications

(14 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Plasmid transfer has been demonstrated by mating Rhizobium strains and species and selecting for transconjugants (1,4,11,18,23). However, in our experiments, cryptic plasmid transfer or other genetic interchange was not de-tected in nodules of M. sativa inoculated with paired R. meliloti competitors.…”

Section: Discussioncontrasting

confidence: 66%

Cryptic plasmid and rifampin resistance in Rhizobium meliloti influencing nodulation competitiveness

Bromfield¹,

Lewis²,

Barran³

1985

J Bacteriol

View full text Add to dashboard Cite

An assessment was made of the relative contributions of a spontaneous mutation to rifampin resistance and a cryptic plasmid, pTA2, to competitive nodulation of Medicago saliva by a strain of Rhizobium meliloti. This was facilitated by use of rifampin-resistant derivatives of this strain in which pTA2 was originally present, cured, or reintroduced. Both curing of pTA2 and spontaneous mutation to rifampin resistance significantly influenced nodulating competitiveness, but the effect of rifampin resistance was greater and such that the contribution of pTA2 was evident only in cases in which paired competitors had the common rifampin resistance background. The data suggest that rifampin-resistant derivatives contain an altered RNA polymerase insensitive to the action of rifampin. All R. melhoti derivatives had symbiotic characteristics and phage susceptibility patterns similar to those of the wild type. Plasmid pTA2 transfer or other genetic interchange was not detected in nodules of M. saliva inoculated with paired competitors.Legume inoculation in soils containing indigenous Rhizobium populations frequently results in only small proportions of nodules produced by introduced strains (27, 33). Therefore, the improvement of nodulating competitiveness in Rhizobium strains intended for legume inoculation is of considerable practical importance.It has been reported that the symbiotic plasmid in R. leguminosarum (5), antibiotic resistance in R. trifolii (8), and genetic factors in the legume host (10, 17) influence competitive success in nodulation. However, the genetic basis of nodulating competitiveness in Rhizobium spp. is still not understood. Bromfield (6) reported that a derivative of a strain of R. meliloti obtained by spontanteous mutation to rifampin resistance and cured of a 135-megadalton cryptic plasmid (pTA2) was significantly less competitive in nodulation than the wild type. The main objective of this investigation was to assess the relative contributions of spontaneous mutation to rifampin resistance and plasmid pTA2 to competitive nodulation by this strain of R. meliloti. This was facilitated by use of rifampin-resistant derivatives with pTA2 originally present, eliminated, or reintroduced. MATERIALS AND METHODS R. meliloti and medium. The R. meliloti strains used in this investigation are described in Table 1. All R. meliloti were characterized by the procedure of Lesley (20) with the same 16 distinct phages. R. meliloti IZ450(pTA2) and derivatives were grown on yeast extract-mannitol agar (YEM) modified from Fred et al. (16) by using 1 g of yeast extract (Difco Laboratories) per liter and omitting CaCO3. Competition experiment. Competition for nodulation between R. meliloti IZ450(pTA2) and derivatives was examined with Medicago sativa cv. Apollo grown in modified Leonard jars (32) containing quartz sand and supplied with nitrogen-free nutrient solution (22). Seedlings from surfacesterilized seed (32) were planted and inoculated with 1 ml of cell suspension washed from the surface of a YEM slope in * Cor...

show abstract

Section: Discussioncontrasting

confidence: 66%

Cryptic plasmid and rifampin resistance in Rhizobium meliloti influencing nodulation competitiveness

Bromfield¹,

Lewis²,

Barran³

1985

J Bacteriol

View full text Add to dashboard Cite

show abstract

“…Methods commonly used with other bacterial species (including fast-growing Rhizobium species), such as transformation or conjugation, are difficult to apply to slow-growing Rhizobium species. Kuykendall (17), Pilacinski and Schmidt (23), and Khmelnitsky et al (16) have been successful in introducing one or more P1 group plasmids (R1822, pRD1, RP4, and R68.45) into R. japonicum with the hope that they will promote chromosome mobilization. Only Khmelnitsky et al (16) have obtained a low level of chromosome transfer by plasrnid-promoted mobilization.…”

mentioning

confidence: 99%

Induced plasmid-genome rearrangements in Rhizobium japonicum

Atherly¹

1984

J Bacteriol

View full text Add to dashboard Cite

The P group resistance plasmids RP1 and RP4 were introduced into Rhizobium japonicum by polyethylene-glycol-induced transformation of spheroplasts. After cell wall regeneration, transformants were recovered by selecting for plasmid determinants. Plant nodulation, nitrogen fixation, serological, and bacterial genetics studies revealed that the transformants were derived from the parental strains and possessed the introduced plasmid genetic markers. Agarose gel electrophoresis, restriction enzyme analysis, and DNA hybridization studies showed that many of the transformant strains had undergone genome rearrangements. In the RP1 transformants, chromosomal DNA was found to have transposed into a large indigenous plasmid of R. japonicum, producing an even larger plasmid, and the introduced R plasmid DNA was found to be chromosomally integrated rather than replicating autonomously or integrated into the endogenous plasmid. Seemingly, a similar section of chromosomal DNA was involved in all the genomic rearrangements observed in the R. japonicum RP1 and RP4 transformant strains.

show abstract

“…Agrobacterium and Rhizobium strains were incubated at 26°C and Escherichia coli at 37°C. For agrocin production yeastmannitol broth (YMB; Pilacinski & Schmidt 1981) and minimal medium (Engler et al 1975) were used. Antibacterial drugs were added at the following concentrations (,ug/ml): ampicillin (Ap), 25; erythromycin (Em), 25; kanamycin (Km), 50; nalidixic acid (Nal), 100; rifampicin (Rifj, 25; spectinomycin (Sp), 100 and streptomycin (Sm), 100.…”

Section: Media a N D G R O W T H C O N D I T I O N Smentioning

confidence: 99%

Expression of an agrocin‐encoding plasmid of Agrobacterium tumefaciens in Rhizobium meliloti

Hendson

Thomson

1986

Journal of Applied Bacteriology

View full text Add to dashboard Cite

Plasmid RP4 was used to mobilize the agrocin 84‐encoding plasmid, pAg396, from Agrobacterium tumefaciens strain 396 to A. tumefaciens C58 and C58CI as well as Rhizobium meliloti. It was transferred to, but not stably maintained in, R. leguminosarum. It could not be transferred to R. lupini, R. japonicum or R. trifolii. Plasmid pAg396 did not segregate in R. meliloti and produced levels of agrocin comparable to the parental strain A. tumefaciens 396. The potential of agrocin producing R. meliloti in biological control of crown gall is being investigated.

show abstract

Plasmid transfer within and between serologically distinct strains of Rhizobium japonicum, using antibiotic resistance mutants and auxotrophs

Cited by 22 publications

References 6 publications

Cryptic plasmid and rifampin resistance in Rhizobium meliloti influencing nodulation competitiveness

Cryptic plasmid and rifampin resistance in Rhizobium meliloti influencing nodulation competitiveness

Induced plasmid-genome rearrangements in Rhizobium japonicum

Expression of an agrocin‐encoding plasmid of Agrobacterium tumefaciens in Rhizobium meliloti

Contact Info

Product

Resources

About