Alfalfa yield response to inoculation with recombinant strains of Rhizobium meliloti with an extra copy of dctABD and/or modified nifA expression

  title={Alfalfa yield response to inoculation with recombinant strains of Rhizobium meliloti with an extra copy of dctABD and/or modified nifA expression},
  author={Andrew H. Bosworth and M. Kevin Williams and Kenneth A. Albrecht and Robert W. Kwiatkowski and Jim L. Beynon and T. R. Hankinson and Clive W. Ronson and Frank Cannon and T. J. Wacek and Eric W. Triplett},
  journal={Applied and Environmental Microbiology},
  pages={3815 - 3832}
The construction of rhizobial strains which increase plant biomass under controlled conditions has been previously reported. However, there is no evidence that these newly constructed strains increase legume yield under agricultural conditions. This work tested the hypothesis that carefully manipulating expression of additional copies of nifA and dctABD in strains of Rhizobium meliloti would increase alfalfa yield in the field. The rationale for this hypothesis is based on the positive… 

Construction and Environmental Release of aSinorhizobium meliloti Strain Genetically Modified To Be More Competitive for Alfalfa Nodulation

This work investigated whether the putA gene could be used as a means of increasing the competitiveness of S. meliloti strains under agricultural conditions by using it as the inoculum in a contained field experiment at León, Spain and found that the frequency of nodule occupancy was higher with inoculum containing the modifiedPutA gene.

Increase in Alfalfa Nodulation, Nitrogen Fixation, and Plant Growth by Specific DNA Amplification in Sinorhizobium meliloti

In the case of the strains with a moderate increase in copy number, symbiotic properties were improved significantly, and the inoculation of alfalfa with these strains resulted in an enhancement of plant growth.

Engineering the nifH Promoter Region and Abolishing Poly-β-Hydroxybutyrate Accumulation in Rhizobium etli Enhance Nitrogen Fixation in Symbiosis with Phaseolus vulgaris

To the authors' knowledge, this is the first report of increased seed yield and nutritional content in the common bean obtained by using only the genetic material already present in Rhizobium.

Symbiotic activity of alfalfa rhizobia (Sinorhizobium meliloti) strains with genetically modified transport of dicarboxylic acids

Factor analysis has demonstrated that the amplification of dctABD genes significantly influences these characteristics of symbiotic efficiency in all the performed experiments, while the effects ofdctA, nifA, and ntrA depend on the plant cultivar and vegetation conditions.

Symbiotic performance of some modified Rhizobium etli strains in assays with Phaseolus vulgaris beans that have a high capacity to fix N2

Rhizobium etli and R. tropici form nitrogen-fixing nodules on Phaseolus vulgaris (common bean). In the hope that R. etli strains with additional citrate synthase genes have better carbon economies,

Mutation in the ntrR gene, a member of the vap gene family, increases the symbiotic efficiency of Sinorhizobium meliloti.

In specific plant organs, namely the root nodules of alfalfa, fixed nitrogen (ammonia) produced by the symbiotic partner Sinorhizobium meliloti supports the growth of the host plant in

A field study with genetically engineered alfalfa inoculated with recombinant Sinorhizobium meliloti: effects on the soil ecosystem

It is suggested that the genetically engineered organisms caused detectable changes in some components of the soil ecosystem.

Enhanced competitiveness of a Bradyrhizobium japonicum mutant strain improved for nodulation and nitrogen fixation

Bradyrhizobium japonicum strain TA-11NOD+, with altered indole biosynthesis, exhibited enhanced nodulation and nitrogen fixation on soybean in previous greenhouse studies. In this study, field

Nickel Availability and hupSL Activation by Heterologous Regulators Limit Symbiotic Expression of theRhizobium leguminosarum bv. Viciae Hydrogenase System in Hup− Rhizobia

The results indicate that efficient transcriptional activation by heterologous regulators and processing of the hydrogenase as a function of the availability of nickel to the bacteroid are relevant factors that affect hydrogenase expression inheterologous rhizobia.



Improvement of Rhizobium Inoculants

  • A. Paau
  • Medicine, Biology
    Applied and environmental microbiology
  • 1989
This article corrects the article on p. 865 in vol.

Dicarboxylic acid transport in Bradyrhizobium japonicum: use of Rhizobium meliloti dct gene(s) to enhance nitrogen fixation

The regulation of dicarboxylic acid transport by factors such as metabolic inhibitors and the presence of additional carbon sources was similar in both the wild-type and the engineered strains.

Clustering of nitrogen fixation (nif) genes in Rhizobium meliloti

A cloned 17.3-kilobase region of the Rhizobium meliloti genome with homology to the Klebsiella pneumoniae nitrogenase structural genes was studied and suggested that at least three distinct units of gene expression are present in this region.

Symbiotic properties of rhizobia containing a flavonoid-independent hybrid nodD product

Comparison of the symbiotic properties of rhizobia containing the constitutive nodD hybrid gene with those of rhZobia containing various wild-type nodD genes indicates that the activation of the nodD product by flavonoids is of crucial importance during the process of infection thread formation and, surprisingly, also during nitrogen fixation.

Mutant Strains of Rhizobium japonicum with Increased Ability to Fix Nitrogen for Soybean

Two mutant strains of Rhizobium japonicum used in commercial inoculants were mutagenized and screened by a rapid effectiveness assay with soybean plants and expressed greater symbiotic nitrogen-fixing activity than the wild type in the presence and absence of fixed nitrogen.

Organization and expression of Rhizobium meliloti nitrogen fixation genes.

The boundaries of a nif gene cluster in Rhizobium meliloti were determined by Tn5 mutagenesis by identifying a 5- to 6-kb transcript that corresponds to the nitrogenase structural gene operon.

Physical and genetic characterization of Rhizobium meliloti symbiotic mutants.

A set of 19 symbiotic mutants of Rhizobium meliloti obtained by a Tn5 "suicide plasmid" mutagenesis procedure was characterized genetically and physically, and it was shown that R.meliloti strain 1021, like other R.Meliloti strains, contains a very large indigenous plasmids that carries the structural genes for nitrogenase (nifHDK genes).

Field release of genetically-engineered Rhizobium meliloti and Bradyrhizobium japonicum strains

The objectives of BioTechnica International’s research and development program in nitrogen fixation are to develop seed-coating products for alfalfa and soybean that improve crop productivity and contain genetically engineered strains of Rhizobium meliloti or BradyrhZobium japonicum with improved nitrogen-fixing and competitive abilities.