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Safronova V.I.,All Russia Research Institute for Agricultural Microbiology ARRIAM | Kuznetsova I.G.,All Russia Research Institute for Agricultural Microbiology ARRIAM | Sazanova A.L.,All Russia Research Institute for Agricultural Microbiology ARRIAM | Kimeklis A.K.,All Russia Research Institute for Agricultural Microbiology ARRIAM | And 8 more authors.
Archives of Microbiology | Year: 2015

Eleven extra-slow-growing strains were isolated from nodules of the relict legume Vaviloviaformosa growing in North Ossetia (Caucasus) and Armenia. All isolates formed a single rrs cluster together with the type strain Tardiphagarobiniae LMG 26467T, while the sequencing of the 16S–23S rDNA intergenic region (ITS) and housekeeping genes glnII, atpD, dnaK, gyrB, recA and rpoB divided them into three groups. North Ossetian isolates (in contrast to the Armenian ones) were clustered separately from the type strain LMG 26467T. However, all isolates were classified as T. robiniae because the DNA–DNA relatedness between them and the type strain LMG 26467T was 69.6 % minimum. Two symbiosis-related genes (nodM and nodT) were amplified in all isolated Tardiphaga strains. It was shown that the nodM gene phylogeny is similar to that of ITS and housekeeping genes. The presence of the other symbiosis-related genes in described Tardiphaga strains, which is recently described genus of rhizobia, as well as their ability to form nodules on any plants are under investigation. © 2015, Springer-Verlag Berlin Heidelberg.

Dolgikh E.A.,All Russia Research Institute for Agricultural Microbiology ARRIAM | Leppyanen I.V.,All Russia Research Institute for Agricultural Microbiology ARRIAM | Osipova M.A.,All Russia Research Institute for Agricultural Microbiology ARRIAM | Savelyeva N.V.,Saint Petersburg State University | And 4 more authors.
Plant Biology | Year: 2011

In legumes, perception of rhizobial lipochitooligosacharide-based molecules (Nod factors) and subsequent signal transduction triggers transcription of plant symbiosis-specific genes (early nodulins). We present genetic dissection of Nod factor-controlled processes in Pisum sativum using two early nodulin genes PsENOD12a and PsENOD5, that are differentially up-regulated during symbiosis. A novel set of non-nodulating pea mutants in fourteen loci was examined, among which seven loci are not described in Lotus japonicus and Medicago truncatula. Mutants defective in Pssym10, Pssym8, Pssym19, Pssym9 and Pssym7 exhibited no PsENOD12a and PsENOD5 activation in response to Nod factor-producing rhizobia. Thus, a conserved signalling module from the LysM receptor kinase encoded by Pssym10 down to the GRAS transcription factor encoded by Pssym7 is essential for Nod factor-induced gene expression. Of the two investigated genes, PsENOD5 was more strictly regulated; not only requiring the SYM10-SYM7 module, but also SYM35 (NIN transcription factor), SYM14, SYM16 and SYM34. Since Pssym35, Pssym14, Pssym34 and Pssym16 mutants show arrested infection and nodule formation at various stages, PsENOD5 expression seems to be essential for later symbiotic events, when rhizobia enter into plant tissues. Activation of PsENOD12a only requires components involved in early steps of signalling and can be considered as a marker of early symbiotic events preceding infection. © 2010 German Botanical Society and The Royal Botanical Society of the Netherlands.

Azarakhsh M.,Saint Petersburg State University | Kirienko A.N.,All Russia Research Institute for Agricultural Microbiology ARRIAM | Zhukov V.A.,All Russia Research Institute for Agricultural Microbiology ARRIAM | Lebedeva M.A.,Saint Petersburg State University | And 2 more authors.
Journal of Experimental Botany | Year: 2015

KNOX transcription factors (TFs) regulate different aspects of plant development essentially through their effects on phytohormone metabolism. In particular, KNOX TF SHOOTMERISTEMLESS activates the cytokinin biosynthesis ISOPENTENYL TRANSFERASE (IPT) genes in the shoot apical meristem. However, the role of KNOX TFs in symbiotic nodule development and their possible effects on phytohormone metabolism during nodulation have not been studied to date. Cytokinin is a well-known regulator of nodule development, playing the key role in the regulation of cell division during nodule primordium formation. Recently, the activation of IPT genes was shown to take place during nodulation. Therefore, it was hypothesized that KNOX TFs may regulate nodule development and activate cytokinin biosynthesis upon nodulation. This study analysed the expression of different KNOX genes in Medicago truncatula Gaertn. and Pisum sativum L. Among them, the KNOX3 gene was upregulated in response to rhizobial inoculation in both species. pKNOX3::GUS activity was observed in developing nodule primordium. KNOX3 ectopic expression caused the formation of nodule-like structures on transgenic root without bacterial inoculation, a phenotype similar to one described previously for legumes with constitutive activation of the cytokinin receptor. Furthermore, in transgenic roots with MtKNOX3 knockdown, downregulation of A-type cytokinin response genes was found, as well as the MtIPT3 and LONELYGUY2 (MtLOG2) gene being involved in cytokinin activation. Taken together, these findings suggest that KNOX3 gene is involved in symbiotic nodule development and may regulate cytokinin biosynthesis/activation upon nodule development in legume plants. © 2015 The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Belimov A.A.,All Russia Research Institute for Agricultural Microbiology ARRIAM | Dodd I.C.,Lancaster University | Safronova V.I.,All Russia Research Institute for Agricultural Microbiology ARRIAM | Dumova V.A.,All Russia Research Institute for Agricultural Microbiology ARRIAM | And 3 more authors.
Plant Physiology and Biochemistry | Year: 2014

Although endogenous phytohormones such as abscisic acid (ABA) regulate root growth, and many rhizobacteria can modulate root phytohormone status, hitherto there have been no reports of rhizobacteria mediating root ABA concentrations and growth by metabolising ABA. Using a selective ABA-supplemented medium, two bacterial strains were isolated from the rhizosphere of rice (Oryza sativa) seedlings grown in sod-podzolic soil and assigned to Rhodococcus sp. P1Y and Novosphingobium sp. P6W using partial 16S rRNA gene sequencing and phenotypic patterns by the GEN III MicroPlate test. Although strain P6W had more rapid growth in ABA-supplemented media than strain P1Y, both could utilize ABA as a sole carbon source in batch culture. When rice seeds were germinated on filter paper in association with bacteria, root ABA concentration was not affected, but shoot ABA concentration of inoculated plants decreased by 14% (strain P6W) and 22% (strain P1Y). When tomato (Solanum lycopersicum) genotypes differing in ABA biosynthesis (ABA deficient mutants flacca - flc, and notabilis - not and the wild-type cv. Ailsa Craig, WT) were grown in gnotobiotic cultures on nutrient solution agar, rhizobacterial inoculation decreased root and/or leaf ABA concentrations, depending on plant and bacteria genotypes. Strain P6W inhibited primary root elongation of all genotypes, but increased leaf biomass of WT plants. In WT plants treated with silver ions that inhibit ethylene perception, both ABA-metabolising strains significantly decreased root ABA concentration, and strain P6W decreased leaf ABA concentration. Since these changes in ABA status also occurred in plants that were not treated with silver, it suggests that ethylene was probably not involved in regulating bacteria-mediated changes in ABA concentration. Correlations between plant growth and ABA concentrations in planta suggest that ABA-metabolising rhizobacteria may stimulate growth via an ABA-dependent mechanism. © 2013 Elsevier Masson SAS.

Safronova V.I.,All Russia Research Institute for Agricultural Microbiology ARRIAM | Kuznetsova I.G.,All Russia Research Institute for Agricultural Microbiology ARRIAM | Sazanova A.L.,All Russia Research Institute for Agricultural Microbiology ARRIAM | Kimeklis A.K.,All Russia Research Institute for Agricultural Microbiology ARRIAM | And 8 more authors.
Antonie van Leeuwenhoek, International Journal of General and Molecular Microbiology | Year: 2015

The Gram–negative, rod-shaped slow-growing strains Vaf-17, Vaf-18T and Vaf-43 were isolated from the nodules of Vavilovia formosa plants growing in the hard-to-reach mountainous region of the North Ossetian State Natural Reserve (north Caucasus, Russian Federation). The sequencing of 16S rDNA (rrs), ITS region and five housekeeping genes (atpD, dnaK, recA, gyrB and rpoB) showed that the isolated strains were most closely related to the species Bosea lathyri (class Alphaproteobacteria, family Bradyrhizobiaceae) which was described for isolates from root nodules of Lathyrus latifolius. However the sequence similarity between the isolated strains and the type strain B. lathyri LMG 26379T for the ITS region was 90 % and for the housekeeping genes it was ranged from 92 to 95 %. All phylogenetic trees, except for the rrs-dendrogram showed that the isolates from V. formosa formed well-separated clusters within the Bosea group. Differences in phenotypic properties of the B. lathyri type strain and the isolates from V. formosa were studied using the microassay system GENIII MicroPlate BioLog. Whole-cell fatty acid analysis showed that the strains Vaf-17, Vaf-18T and Vaf-43 had notable amounts of C16:0 (4.8–6.0 %), C16:0 3-OH (6.4–6.6 %), C16:1 ω5c (8.8–9.0 %), C17:0 cyclo (13.5–13.9 %), C18:1 ω7c (43.4–45.4 %), C19:0 cyclo ω8c (10.5–12.6 %) and Summed Feature (SF) 3 (6.4–8.0 %). The DNA–DNA relatedness between the strains Vaf-18T and B. lathyri LMG 26379T was 24.0 %. On the basis of genotypic and phenotypic analysis a new species Bosea vaviloviae sp. nov. (type strain RCAM 02129T = LMG 28367T = Vaf-18T) is proposed. © 2015, Springer International Publishing Switzerland.

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