Isolation and characterization of Rhizobium meliloti Tn5 mutants showing enhanced symbiotic effectiveness

Sharypova, L. A.; Онищук, О. П.; Chesnokova, Olga; Fomina-Eshchenko, Julia G.; Симаров, Б. В.

doi:10.1099/00221287-140-3-463

Cited by 22 publications

(29 citation statements)

References 10 publications

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“…Nadezhda and G. officinalis var. E-103 (Maykop region) from the VIR (N. I. Vavilov Russia Research Institute of Plant Genetic Resources) collection for 30 days under nitrogen-deficient sterile conditions in glass tubes containing vermiculite (30). Each strain was tested in two replicates with each host plant.…”

Section: Methodsmentioning

confidence: 99%

Symbiotic and Genetic Diversity of Rhizobium galegae Isolates Collected from the Galega orientalis Gene Center in the Caucasus

Andronov

Terefework

Roumiantseva

et al. 2003

Appl Environ Microbiol

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This paper explores the relationship between the genetic diversity of rhizobia and the morphological diversity of their plant hosts. Rhizobium galegae strains were isolated from nodules of wild Galega orientalis and Galega officinalis in the Caucasus, the center of origin for G. orientalis. All 101 isolates were characterized by genomic amplified fragment length polymorphism fingerprinting and by PCR-restriction fragment length polymorphism (RFLP) of the rRNA intergenic spacer and of five parts of the symbiotic region adjacent to nod box sequences. By all criteria, the R. galegae bv. officinalis and R. galegae bv. orientalis strains form distinct clusters. The nod box regions are highly conserved among strains belonging to each of the two biovars but differ structurally to various degrees between the biovars. The findings suggest varying evolutionary pressures in different parts of the symbiotic genome of closely related R. galegae biovars. Sixteen R. galegae bv. orientalis strains harbored copies of the same insertion sequence element; all were isolated from a particular site and belonged to a limited range of chromosomal genotypes. In all analyses, the Caucasian R. galegae bv. orientalis strains were more diverse than R. galegae bv. officinalis strains, in accordance with the gene center theory.Rhizobium galegae (14) is a species that forms an effective symbiosis with plants of Galega orientalis and Galega officinalis, the only species in the genus Galega (Fabaceae) that have been studied for symbiosis. This symbiotic system represents a sharply defined cross-inoculation group. However, there are some differences in symbiotic performance. R. galegae strains are able to infect both Galega species, but strains isolated from G. officinalis form effective nodules on that plant and ineffective nodules on G. orientalis, while the converse is true for strains from G. orientalis (16). This finding, along with a wide range of phenotypic and genotypic approaches using numerical taxonomy (15), phage typing, DNA homology (13, 40), lipopolysaccharide and protein patterns (16), plasmid profiling (29), phylogeny of ribosomal genes (25, 35), randomly amplified polymorphic DNA, and repetitive PCR (21, 28), led to the proposal of two biovars for strains forming an effective symbiosis with G. officinalis (R. galegae bv. officinalis) and G. orientalis (R. galegae bv. orientalis) (24). Symbiosis-related genetic traits were found to be the main factor in genetic divergence between the biovars (24). G. orientalis is a good fodder plant with some widely used cultivars, whereas G. officinalis is rather poisonous because of its high alkaloid content and has no agricultural importance.The interesting symbiotic properties, together with the extensive taxonomic knowledge about R. galegae, prompted us to use the species to answer important questions related to the diversity and evolution of rhizobia and their symbiosis with legumes. A recent study indicated that R.galegae bv. orientalis strains have lower genetic diversity than R. galegae ...

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Section: Methodsmentioning

confidence: 99%

Symbiotic and Genetic Diversity of Rhizobium galegae Isolates Collected from the Galega orientalis Gene Center in the Caucasus

Andronov

Terefework

Roumiantseva

et al. 2003

Appl Environ Microbiol

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“…У S. meliloti гены, контроли-рующие СЭ, были выявлены путем анализа Tn5-мутан-тов, отобранных по способности повышать массу иноку-лированных растений люцерны (Sharypova et al, 1994).…”

Section: Discussionunclassified

“…Такой фенотип был обозна-чен Eff ++ , а гены, мутации в которых приводят к его появлению, были назва-ны «генами эффективности» (eff-гены) (Sharypova et al, 1994).…”

Section: Introductionunclassified

“…Молекулярно-биологический анализ eff-генов клубеньковых бактерий показал, что СЭ является полигенным признаком и контролируется сложной системой генов (Sharypova et al, 1994(Sharypova et al, , 1999Olach et al, 2001). При этом инактивация одних генов в результате мутаций может приводить к снижению или полной утрате СЭ, в то же время инактивация других генов -к воз-растанию СЭ.…”

Section: Introductionunclassified

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Identification of new genes of nodule bacteria sinorhizobium meliloti involved in the control of efficiency of symbiosis with alfalfa medicago sativa

Онищук

Курчак

Chizhevskaya

et al. 2014

Ecological genetics

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Background. Alfalfa root nodule bacteria (Sinorhizobium meliloti) are among the most active symbiotic N2-fixers. Their symbiotic efficiency (SE) defined as an ability to enhance the productivity of inoculated host plants is the polygenic trait controlled by a complicated system of genes, inactivation of which can result in either decrease or increase of SE. Analysis of previously identified eff-genes, whose mutations result in SE increase, revealed their location in different parts of genome (chromosome or megaplasmids) and demonstrated that these genes are not involved in operation of nitrogenase system. Mutations in these genes have pleiotropic effects, changing various cultural-biochemical properties of bacteria. Materials and methods. The object of research were the laboratory S. meliloti strain CXM1-105 and its Tn5-mutants with Eff++ phenotype, which are able to grow in diagnostic media containing indicator of cell redox potential ТТC, herbicide 2М-4ХМ or the Congo Red dye. New eff-genes were identified using the modified method of “inverted” PCR. Results. We obtained three Tn5 mutants with an increased SE in which the symbiotic phenotypes are dependent on the host. Two-factor analysis of variance demonstrated that the genotypic difference between mutants is most pronounced under the salt stress, while in its absence SE is determined mostly by the host genotype. Molecular-biological analysis revealed that the T4 mutant harbours the Tn5 insertion in the mtaD gene, T795 - in the thiC gene, and M3 - in the gene which encodes a protein belonging to the GntR family of transcription regulators. Conclusion. We demonstrated firstly that mutations in genes involved in transcription regulation, phosphonate metabolism and thiamine biosynthesis may result in a SE increase. The “inverted” PCR method enabled us to rapidly extract DNA fragments flanking the transposon, which suggests applicability of this method for identification of new rhizobia genes marked by Tn5.

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“…Plants inoculated with TA11 NOD + contained signifi cantly more nitrogen per plant (due to an increase in overall nodule number) than did plants inoculated with wild type bacteria 77 . Sharypova et al(1994) 78 showed enhanced symbiotic effectiveness (Eff + ) from S. meliloti XMI-105 and XMI-188. The frequency of Eff + mutants in strain XMI-188 was higher than in the XMI-105 (1.1 % versus 0.4 %).…”

Section: Effect Of Auxotrophy On Symbiotic Processmentioning

confidence: 99%

Auxotrophy in rhizobia revisited

Yadav

2007

Indian J Microbiol

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Among the various types of mutations studied in rhizobia, the auxotrophic mutations (which confer on the mutants the inability to synthesize certain essential substances such as amino acids, vitamins and nucleic acids), are the most favoured ones as these can be used as suitable markers for genetic analysis. An important property of rhizobia is their effectiveness i.e. their ability to fi x atmospheric nitrogen into ammonia within the nodule. Special interest in this category of mutations by rhizobial geneticists is due to the fact that there is a strong correlation between the metabolic defects and the ineffectiveness (Nod -and/or Fix -) of the rhizobial strains. Auxotrophic mutants of various species of rhizobia with defects in the synthesis of nucleic bases, vitamins and amino acids have been obtained by mutagenising with physical, chemical and Tn5 mutagens. These mutants have been used in mapping studies as well as in establishing a correlation between its metabolic requirement and symbiotic relationship with the host plant. The present review deals with the isolation of auxotrophs, and their genetic, biochemical and symbiotic characterization. The review also encompasses the studies on the elucidation of biosynthetic pathways of nutritional substances in rhizobia.

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Isolation and characterization of Rhizobium meliloti Tn5 mutants showing enhanced symbiotic effectiveness

Cited by 22 publications

References 10 publications

Symbiotic and Genetic Diversity of Rhizobium galegae Isolates Collected from the Galega orientalis Gene Center in the Caucasus

Symbiotic and Genetic Diversity of Rhizobium galegae Isolates Collected from the Galega orientalis Gene Center in the Caucasus

Identification of new genes of nodule bacteria sinorhizobium meliloti involved in the control of efficiency of symbiosis with alfalfa medicago sativa

Auxotrophy in rhizobia revisited

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