[Simulation of bacteria-plant coevolution in the mutualistic symbiosis].
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 (reproductive potentials) in both partners as dependent on the symbiotic efficiency determined by proportion of N2-fixing rhizobia strain in root nodules. Computer experiments demonstrated that microevolution of the simulated system may follow either oscillatory or quasi-monotonous regime as dependent of frequency-dependent selection (FDS) in plant population. Negative FDS occurring in the bacterial population during competition for nodulation in combination with the positive partners' feedback may lead to anchoring the bacterial mutations which lead either to acquisition of mutualistic traits or to changes in specificity of their expression. Anchoring of the mutualistic strains occurs most successfully in the quasi-monotonous regime and results in the improvement of genetic stability in symbiotic system.
Provorov
N A
NA
Vorob'ev
N I
NI
D000220:Adaptation, Biological / Q000502:physiology; D005075:Biological Evolution; D003198:Computer Simulation; D017753:Ecosystem; D007887:Fabaceae / Q000502:physiology*; D008954:Models, Biological; D012231:Rhizobium / Q000502:physiology*; D053204:Root Nodules, Plant / Q000382:microbiology / Q000502:physiology; D013559:Symbiosis