A Study of Surface Interactions Between Rhizobium Bacteroids and the Peribacteroid Membrane using Monoclonal Antibodies

Abstract

As a way of supplementing the other techniques for research into the molecular biology of the Rhizobium-legume symbiosis, we have chosen to apply the technology of monoclonal antibodies to the problem of surface interactions between the endosymbiotic bacteroid and the encircling plant-derived peribacteroid membrane. Using monoclonal antibodies in conjunction with the recently developed techniques for immunogold electron microscopy (Robertson et al 1985), there are three kinds of biological questions that we want to ask. Firstly, how is this interaction set up? In other words, how does the Rhizobium cell become taken up by the plant cell plasma membrane; what governs subsequent divisions of the intracellular bacterium and the concomitant division of the encircling peribacteroid membrane (Robertson & Lyttleton 1984); and what physical interactions occur between bacteroid and peribacteroid membrane surfaces which might control morphogenesis? A second class of question relates to membrane transport phenomena — what kinds of molecules are transported across the bacteroid outer membrane and the peribacteroid membrane and how is this achieved? The third class of question relates to the ultimate breakdown of the symbiosis — nodule senescence — which is in some way related to the nitrogen status of the whole plant.