About the Cover
The mechanisms that control legume root nodulation by host-specific Rhizobium interactions are not well understood. Lectins have been proposed to play a role in nodulation host specificity by mediating rootbacterial interactions. On pages 1233-1249 of this issue, van Rhijn et al. show that the presence of functional soybean lectin protein within transgenic Lotus corniculatus root hairs enables Bradyrhizobium japonicum, a nitrogen-fixing bacterium specific for soybean, to bind to L. corniculatus roots and initiate nodulelike outgrowths. Experiments with bacterial mutants suggest that a component of the B. japonicum exopolysaccharide surface, rather than Nod factor, is required for interaction with the soybean lec-tin and for the extension of B. japonicum host range to the L. corniculatus plants. These results demonstrate that lectins play a critical role in the host-specific interaction between nitrogen-fixing bacteria and legume roots but that other factors are required to induce nitrogen-fixing nodules.
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Copyright © 2007 by the American Society of Plant Biologists
