Role of signal exchange in control of <i>Rhizobium </i>- legume symbiosis specificity
The signal molecules produced by legume plants and soil bacteria rhizobia and involved in early steps of symbiosis regulation were identified through the evaluation of molecular mechanisms of plant-rhizobia communication. The molecular dialog between plants and rhizobia is initiated by plant flavanoids inducing the synthesis and secretion of lipochitooligosaccharide molecules Nod factors by rhizobial bacteria. Nod factors are N-acetylglucosamine oligomers, modified by fatty acid and certain chemical groups. Nod factors trigger a set of plant reactions resulting in a formation of root nodules - nitrogen fixing symbiotic organs. Fine chemical structure of signal molecules determines host specificity of the symbiosis. Nod factors are active in low concentrations and possess mitogenic and morphogenic activity, therefore they are recognized as the new class of growth regulators. In this paper the modern data about study of Nod factor perception mechanisms and signal transduction pathway in legume plants are presented and considered with perspective for future application of these knowledge for practical increasing of symbiosis efficiency from plant side. This work was supported by RFBR 07-08-00700a (Russian Foundation of Basic Research), CRDF RUXO-012-ST-06 (BP2M12) and HIII-5399. 2008. 4, RFBR-NWO (06-04-89000-НВОЦ-а) grants.