RESUMO
The review sums up the long experience of the authors and other researchers in studying the genetic system of garden pea (Pisum sativum L.), which controls sthe development of nitrogen-fixing symbiosis and arbuscular mycorrhiza. A justified phenotypic classification of pea mutants is presented. Progress in identifying and cloning symbiotic genes is adequately reflected. The feasibility of using double inoculation as a means of increasing the plant productivity is demonstrated, in which the potential of a tripartite symbiotic system (pea plants-root nodule bacteria-arbuscular mycorrhiza) is mobilized.
Assuntos
Bactérias/genética , Micorrizas/genética , Fixação de Nitrogênio/genética , Pisum sativum/genética , Nódulos Radiculares de Plantas/genética , Simbiose/genética , Mutação , Nódulos Radiculares de Plantas/microbiologiaRESUMO
The stages of the legume-rhizobial symbiosis and nodule structure in various legume plants are briefly reviewed. Modern data on the mechanisms involved in the control of nodule initiation and morphogenesis are considered.
Assuntos
Fabaceae/fisiologia , Plantas Medicinais , Rhizobium/fisiologia , Fabaceae/microbiologia , SimbioseRESUMO
Association between traits for hormonal status and nodulation in the mutants of pea Pisum sativum L. with abnormal nodulation and original forms was analyzed. The sensitivity of plant tissues to exogenous phytohormones and changes in the concentration of the major auxin, indolyl-3-acetic acid, in plant roots during interaction with rhizobia were examined. Association between Nod(++)-phenotype and auxin balance was revealed: the supernodulating mutants were more sensitive to auxin treatment than the parental cultivars. Mutations in the sym8 gene, in contrast to those in the sym5 gene, had no effect on plant hormonal status. The level of indolyl-3-acetic acid during interaction with rhizobia depended on the time after inoculation and plant genotype. The mutations affecting nodulation were suggested to change auxin level in roots.
