The role of DMI1 in establishing Ca(2+) oscillations in legume symbioses

Calcium (Ca(2+)) is a key secondary messenger in many plant signaling pathways. One such pathway is the SYM pathway, required in the establishment of both arbuscular mycorrhizal and rhizobial root symbioses with legume host plants.(1) When the host plant has perceived the diffusible signals from the microbial symbionts, one of the earliest physiological responses are Ca(2+) oscillations in and around the nucleus.(2) These oscillations are essential for activating downstream gene expression, but the precise mechanisms of encoding and decoding the Ca(2+) signals are unclear and still under intense investigation. Here we put forward a hypothesis for the mechanism of the cation channel DMI1.