Smart host
Plants are hospitable to useful bacteria but have developed ways to get rid of freeloaders, according to a study by a team of biologists at the University of California in Berkeley, USA.
Led by Ellen Simms, the scientists studied a coastal California lupine (Lupinus arboreus) that harbours nitrogen-fixing bacteria in its roots. They found that the roots respond differently to bacteria that efficiently produce nitrogen than they do to those that don't. In case of the former, root nodules