Nikolai I. Vorobyov

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We created the mathematical model for the evolution of the Efficiency of Mutualistic Symbioses (EMS) which was estimated as the microsymbiont impacts on the host's reproductive potential. Using the example of rhizobia-legume interaction, the relationships were studied between EMS and Functional Integrity of Symbiosis (FIS) which is represented as a measure(More)
Using the examples of diverse interactions among prokaryotes and eukaryotes, the relationships between molecular and population mechanisms of evolution of symbiotic bacteria are addressed. Their circulation in host-environment systems activates microevolutionary factors that direct combinative or reductive genome evolution in facultative, ecologically(More)
A mathematical model is created to assess the inputs of sym gene transfer of in planta multiplication and of interstrain competition into dynamics of the rhizobia populations. Their microevolution is presented as a series of the "infection and release" cycles; each cycle includes transfer of sym genes from virulent initial symbionts to avirulent local(More)
Evolution of beneficial plant–microbe symbioses is presented as a result of selective processes induced by hosts in the associated microbial populations. These processes ensure a success of “genuine mutualists” (which benefit the host, often at the expense of their own fitness) in competition with “symbiotic cheaters” (which consume the resources provided(More)
In order to analyze the microevolutionary processes in host-associated microorganisms, we simulated the dynamics of rhizobia populations composed of a parental strain and its mutants possessing the altered fitness within "plant-soil" system. The population dynamics was presented as a series of cycles (each one involves "soil-->rhizosphere-->nodules-->soil"(More)
We present the mathematical model for coevolution of root nodule bacteria (rhizobia) and leguminous plants which is based on the partners’ positive feedbacks resulted from their metabolic integration. The model parameters were introduced which determine: (1) coordinated changes in plant and bacterial population structures; (2) increase of fitness(More)
The mathematical model for evolution of the plant-microbe facultative mutualistic interactions based on the partners' symbiotic feedbacks is constructed. Using the example of rhizobia-legume symbiosis, we addressed these feedbacks in terms of the metabolic (C<-->N) exchange resulting in the parallel improvements of the partners' fitness (positive(More)
Simulation of cyclic processes in the plant–soil system was used to analyze the effects of factors responsible for the population dynamics of rhizobia on generation of mutants with changedex planta viability. Rhizobial evolution in a system of ecological niches (soil, rhizosphere, nodules) was described with recurrent equations. Computer experiments were(More)
Interactions were studied between oat (Avena sativa) and two bacterial species, Bacillus subtilis and Pantoea agglomerans, in soils contaminated with heavy metals (HM), cadmium (50 mg/kg), and lead (200 mg/kg). Exposure to HM resulted in decreased (by 30–50%) length, mass, and ratio of shoot to root dimensions. Inoculation with bacteria lead to restoration(More)
Mutualistic symbioses are convenient models for analyzing the ecological-genetic mechanisms of progressive evolution, which remains obscure for unitary (free-living) organisms. In the system of legume-rhizobia symbiosis, the hosting of N2-fixing bacteria within extracellular and intracellular compartments of nodules (infection threads, symbiosomes) acquired(More)