RecAX53 is the most recombinogenic protein among the chimeric RecA proteins composed ofEsherichia coli RecA (RecAEc) and Pseudomonas aeruginosa RecA (RecAPa) protein fragments. We found out that RecAX53 protein is more rapid in ATP hydrolysis, dissociation from single-stranded DNA (ssDNA), SSB protein displacement from ssDNA and in association with doublestranded DNA (dsDNA), as compared with RecAEc and RecAPa proteins. These results indicate that the RecAX53 hyper-recombinogenity is caused by high dynamics of this protein - by its rapid association with and dissociation from ssDNA. The ability of RecAX53 to bind actively with dsDNA accounts for the SOS-independent mechanism of hyper-recombination used by this protein.

The genetic control of signal interactions between partners during formation legume-rhizobial symbiosis is examined. The ability of legumes to perceive the signal molecules (Nod-factors) excreting by nodule bacteria appears to be the base of these interactions. The diversity of receptor kinases in legume plants reflects the specificity of interactions with diverse strains of nodule bacteria.

The mutagenic activity of five pesticides actara, sencor, mospilan, pencozeb, fastac widely used for treatment of potato plant lands in Tatarstan was tested in the Ames test. The non toxic concentrations of the pesticides determined in preliminary cytotoxicty test were used in the Ames assay. Pesticides actara, mospilan, pencozeb, fastac did not show mutagenic effect in Salmonella typhimurium TA 100 without rat liver S9 fraction. The weak mutagenic effect of herbicide sencor was established at concentration 1 ug/plate. Metabolic activation in vitro using rat liver S9 fraction decreased the mutagenic activity of sencor and did not alter the mutagenicity rate of the pesticides actara, mospilan, pencozeb and fastac.

Regeneration parameters were optimized and effective selection conditions were sorted out. Transgenic plants of Lemna minor were obtained and their status was confirmed by molecular analysis. Optimized methodology can be used for obtaining transgenic duckweed plants producing recombinant proteins and water body bioremediators.

The model is suggested for evolution of N₂-fixing legume-rhizobia symbiosis implemented under the conditions of multi-strain bacteria competition for inoculation of symbiotic habitats (rhizosphere, nodules). Competitiveness of each strain is characterized by the power coefficients which reflect the operation of frequency-dependent selection in the rhizobia population. When polymorphic bacteria populations are interacting with the dimorphic plant population, the selective pressures in favor of hostspecific symbionts (forming N₂-fixing nodules only with one of the available plant genotypes) are higher than the pressures in favor of non-host-specific symbionts (forming these nodules with both plant genotypes). The highest mutualism efficiency is reached under an intermediate level of plant population diversity.

To study the relatives of two grasses carrying an unusual 2-chromosome genome, Zingeria biebersteiniana and Colpodium versicolor, we have studied the phylogeny relationships of Colpodium sensu lato species and some other grasses by analysis of ITS1 and ITS2 of nuclear rDNA. Z. biebersteiniana (2n = 4, x = 2), Z. trichopoda (2n = 8, x = 2), and C. versicolor (2n = 4, x = 2) form a well supported clade with a single species of Colpodium s. l. complex,Catabrosella araratica (2n = 42, x = 7). All other Colpodium s.l. complex species form another well supported group [{Catabrosella variegata (2n = 10, x = 5), C. subornata (2 n= ?)} Hyalopoa pontica (2n = 28, x = 7), Paracolpodium altaicum (2n = 42, x = 7){Hyalopoa lanatiflora (2n = 28, x = 7), Catabrosa capusii (2n = 20, x = 5), C. aquatica (2n = 20, x = 5)}]. This clade is sister to group [{Puccinelia distans (2n = 42, x = 7), Sclerochloa dura (2n = 14,x = 7)}, Phippsia concinna (2n = 28, x = 7)].