Pods and Nods: a new look at symbiotic nitrogen fixing bacteria.

How can growing a crop plant make a field more fertile? With legumes, this is precisely what happens. Working in partnership with symbiotic bacteria that can create root nodules on their chosen host, legumes can fix atmospheric nitrogen and enhance the nitrogen status of soils. How does this symbiosis develop? And how did it evolve? Bacterial and plant genomics are beginning to provide the answers.