An insight into the legume-Rhizobium interaction

Abstract

Active forms of nitrogen are limiting in soil, but the legume-Rhizobium interaction overcomes this barrier by biological nitrogen fixation and lessens the usage of fertilizers. An understanding exists between the two partners for symbiotic association to share their resources without either one becoming dominant. Certain compounds released by the host legume plants into the rhizosphere attract the rhizobia and activate the expression of rhizobial nod genes that in turn leads to the production and secretion of strain-specific NFs. NF signalling cascade and events of cell divisions in cortex and pericycle and bacterial infection occur in an orchestrated manner and give rise to a nodule. The nodule organogenesis can be studied under nodule formation and bacterial invasion. Depending on the persistence of meristem, nodules formed can be determinate or indeterminate, but ultimately it is the host plant species that determine the type of nodule formed. More than 90 % of arable land experience one or other kind of stress. Stress conditions affect the host plant, rhizobium and also the interaction between the two.