ROS for your roots

Production of reactive oxygen species (ROS) by an NADPH oxidase induces a calcium channel to open and root hair elongation to occur, according to a report from Julia Foreman, Liam Dolan, and colleagues (John Innes Centre, Norwich, UK).

Starting with the rhd2 Arabidopsis mutant, which has stunted root growth and very short root hairs, the authors used transposon-tagging methods to identify the RHD2/AtrbohC gene, which encodes an NADPH oxidase that produces ROS. “When we cloned this gene, we were completely dumbfounded,” says Dolan. But at around the same time, other groups were finding that plants use ROS as second messengers in response to pathogen invasion and to control the movement of guard cells to open and close stomata. What is unusual about the new work is that both the activity and the protein controlling it have...