Abstract
Legume plants form nodules on their roots. In nodules, rhizobium fix nitrogen. Rhizobium in nodules are differentiated to specialized form, called bacteroid. Bacteroids in nodules of galegoid legumes (e.g. M. truncatula, T. repens) show enlarged cell size, endoreduplication, and enhanced membrane permeability, compared with free-living rhizobium. On the other hand, bacteroids in nodules of nongalegoid legumes (e.g. L. japonicus, G. max) don't show such characteristics. In galegoid nodules, Nodule-specific Cysteine Rich peptides (NCRs) are present. On the other hand, NCRs are not present in nongalegoid nodules. Structure of NCRs resemble to antimicrobial peptides. Therefore, characteristics of bacteroids in galegoid nodules are related with NCRs. In this study, we transformed NCRs to L. japonicus and observed the bacteroids. Bacteroids in nodules transformed by NCRs show elongation and enhanced membrane permeability. These results suggest that NCRs are related to characteristics of bacteroids in nodules of galegoid legumes.
