Artificial colonization of non-symbiotic plants roots with the use of lectins

Rhizobia have the ability to increase growth of non-legume plants due to the production of phytohormones and protection of plant from diseases and pathogens. However, the practical use of these beneficial bacteria sometimes fails because of their inability to effectively colonize rhizoplane and rhizosphere of inoculated plants. We chose the legume lectins as a factor that allows plants to form associative symbiosis with rhizobia. To test the fact that transgenic tobacco, tomato and rape roots with pea lectin gene may affect specific interaction with rhizobia, transgenic roots have been artificially inoculated by fluorescently-labeled pea rhizobia R. leguminosarum and east galega rhizobia Rhizobium galega. Microscopic and microbiological tests have shown that the number of adhered R. leguminosarum onto tobacco, rape and tomato roots which transformed with pea lectin gene is higher in comparison with the control, but no such effect through inoculation of these plants with R. galegae has been found. This confirms the interaction of R. leguminosarum with pea lectin at the surface of transformed roots. Undoubtedly, the improvement of recognition and attachment processes by using lectins can lead to the achievement of a stable associative relationship between non-symbiotic plants and rhizobia.     

Genetic markers for search of rhizobia based on symbiotic genes

The possible application of rhizobial symbiotic genes as markers for the search and primary identification of rhizobia from temperate-zone legumes was studied. It was shown that conservative sym genes nifH and nifD could be used as markers for rapid search of rhizobia among the analyzed isolates, while more variable genes nifK and nodC could be used for their primary identification. Efficiency of the proposed method was shown in analysis of bacterial isolates obtained from Onobrychis arenaria and Astragalus cicer root nodules.     

Genetic diversity and phylogeny of root nodule bacteria entering into symbiosis with bitter peavine <Emphasis Type="Italic">Lathyrus vernus</Emphasis> (L.) Bernh.

The genetic diversity and phylogeny of root nodule bacteria entering into symbiosis with bitter peavine Lathyrus vernus (L.) Bernh. (Fabaceae) growing in various regions of the Republic of Bashkortostan were studied. RAPD analysis revealed a high degree of polymorphism of the DNA of the isolated strains giving evidence of the heterogeneity of the microorganisms in question. The study of the phylogeny of microsymbionts based on comparative analysis of the nucleotide sequences of 16S rRNA genes showed that the bacteria isolated from the plant nodules of L. vernus growing on the territory of Ufa and Beloretsk raions belonged to the species Rhizobium leguminosarum, whereas the microsymbionts of L. vernus growing on the territory of Tatyshly raion belonged to the species Rhizobium tropici,@ except for several strains of Rhizobium leguminosarum     

Polymorphism of lectin genes in <Emphasis Type="Italic">Lathyrus</Emphasis> plants

The carbohydrate-binding sequences of the lectin genes from spring vetchling Lathyrus vernus (L.) Bernh., marsh vetchling L. palustris (L.), and Gmelin’s vetchling L. gmelinii (Fitsch) (Fabaceae) were determined. Computer-aided analysis revealed substantial differences between nucleotide and predicted amino acid sequences of the lectin gene regions examined in each of the three vetchling species tested. In the phylogenetic trees based on sequence similarity of carbohydrate-biding regions of legume lectins, the sequences examined formed a compact cluster with the lectin genes of the plants belonging to the tribe Fabeae. In each plant, L. vernus, L. palustris, and L. gmelinii, three different lectin-encoding genes were detected. Most of the substitutions were identified within the gene sequence responsible for coding the carbohydrate-binding protein regions. This finding may explain different affinity of these lectins to different carbohydrates, and as a consequence, can affect the plant host specificity upon development of symbiosis with rhizobium bacteria.     

Genetic Diversity and Phylogeny of Root Nodule Bacteria Isolated from Nodules of Plants of the Lupinaster Genus Inhabiting the Southern Urals

Russian Journal of Genetics - The genetic diversity and phylogeny of root nodule bacteria, microsymbionts of plants of the genus Lupinaster Adans. (L. albus Link and L. pentaphyllus Moench), were...     

The Phylogeny of Triticum L. and Aegilops L. Inferred from Comparative Analysis of Nucleotide Sequences in rDNA Promoter Regions

The process of accumulation of knowledge on wheat and related wild species during the 20th century is briefly reviewed with special reference to the evidence of the recent years on evolution of polyploid wheats and the role of diploid species. The latter serve as potential donors of the genomes, detection of which is particularly important because of the continuing speciation in the tribe Triticeae and artificial development of synthetic forms. The arguments in favor of the donor role for various diploid wheat and aegilops species from the section Sitopsis are compared. It is stated that in the formation of the both lines of polyploid wheats turgidum–aestivumand timopheevi,diploid Aegilops speltoides acted as a maternal form. In addition to cytoplasmic genomes, this aegilops species introduced into them also the B and G nuclear subgenomes. A comparison of nucleotide sequences in the variable part of the promoter of evolutionary conserved rRNA genes in polyploid wheats with their counterparts in diploid wheats and aegilops species confirmed the accepted wheat phylogenies.     

Influence of the introduction of Caragana arborescens on the composition of its root-nodule bacteria

The genetic diversity and phylogeny of root module bacteria entering into symbiotic relations with Caragana arborescens introduced on the territory of the Republic of Bashkortostan (RB) were studied. Analysis of the 85 strains isolated from root-nodules showed that, according to the DNA polymorphism revealed by RAPD analysis, they can be divided into 12 groups. It was found that, both in natural habitats and on the territory of the RB, Caragana arborescens is primarily nodulated by Mesorhizobium bacteria whose 16S rRNA gene sequences differ to some degree from those of the bacteria described earlier by Chinese authors. Bacteria assigned to the genus Phyllobacterium based on their 16S rRNA gene sequences were also revealed in plants growing on the territory of the RB.     

Preparation of fluorescent labeled nodule bacteria strains of wild legumes for their detection in vivo and in vitro

A series of expression vectors containing TurboGFP and TurboRFP genes of fluorescent proteins under the control of the T5 phage constitutive promoter was created for a vital staining of nodule bacteria. These vectors were either obtained using the broad host range pBBRI replicon for labeling of strains, where a marker gene was expressed from a transformed plasmid, or they were prepared using the pRL765 gfp plasmid for labeling of strains via the introduction of genes of fluorescent proteins into the bacterial chromosome. Transformation was shown to be the most convenient method of transfer of constructions into cells of nodule bacteria, as there exists the possibility of spontaneous plasmid mobilization and, consequently, its transition from cells of labeled strains into other soil bacteria if the mob locus is present in vectors needed for conjugation. Fluorescent labeled strains of Rhizobium sp., Mesorhizobium sp., Ensifer (Sinorhizobium) sp., Bradyrhizobium sp., Phyllobacterium sp., and Agrobacterium sp. were prepared using the obtained vector constructions. The suitability of the obtained strains for both in vivo and in vitro experiments was demonstrated.     

The Frequencies of the Genes of Low-Molecular-Weight Alanine-Rich Cold Shock Proteins and Variation of Their Primary Structure in Plants of Temperate Climate

Polymerase chain reaction (PCR) was used to study the frequencies of the gene of a low-molecular-weight alanine-rich cold shock protein in plants of temperate climate. This gene was demonstrated to be specific for the family Cruciferae. Its variability in this family was studied.