There are parallels with nodulation signalling associated with infection: (1) the calcium influx, membrane depolarization and production of ROS are induced by similar concentrations of Nod factor (Oldroyd & Downie, 2004); (2) the Nod-factor receptor NFR5 binds to the small GTPase ROP6, which is involved in infection-thread growth (Ke et al., 2012), and (3) an NADPH oxidase is required for rhizobial infection of Phaseolus bean (Montiel et al., 2013). This evidence concerns the gene FMO5 and infection.