The contribution of SERF1 to root-to-shoot signaling during salinity stress in rice.

Stress perception and communication play important roles in the adaptation of plants to changing environmental conditions. Plant roots are the first organs to detect changes in the soil water potential induced by salt stress. In the presence of salinity stress, root-to-shoot communication occurs to adjust the growth of the whole plant. So far, the phytohormone abscisic acid (ABA), hydraulic signals and reactive oxygen species (ROS) have been proposed to mediate this communication under salt stress. Recently, we identified the rice transcription factor SALT-RESPONSIVE ERF1 (SERF1), which regulates a ROS-dependent transcriptional cascade in roots required for salinity tolerance. Upon salt stress, SERF1 knockout mutant plants show an increased leaf temperature as compared with wild type. As this occurs within the first 20 min of salt stress, we here evaluated the involvement of SERF1 in the perception of salt stress in the shoot. By metabolic profiling and expression analysis we show that the action of SERF1 in signal communication to the shoot is independent from ABA, but does affect the accumulation of ROS-related metabolites and transcripts under short-term salt stress.