REDOX RESPONSIVE TRANSCRIPTION FACTOR1 is involved in age-dependent and systemic stress signaling.

REDOX RESPONSIVE TRANSCRIPTION FACTOR1 (RRTF1) regulates redox homeostasis under stress, however the mechanism is mainly unknown. In a recent publication, we analyzed rrtf1 knockout (ko) and RRTF1 overexpressor lines of Arabidopsis thaliana and showed that RRTF1 plays a crucial role in reactive oxygen species (ROS) production. Ko line produces less and overexpressor lines constitutively high levels of ROS under stress, and the amount of ROS increases with increase in stress and the RRTF1 level in the plant. The transcription factor also activates systemic ROS signaling under stress. (1) In this report, we show that RRTF1 exerts different roles in young and old leaves. While RRTF1 enhances defense responses to high light (HL) stress in young leaves, it induces senescence and chlorosis in older leaves. These findings suggest that RRTF1 and/or RRTF1-mediated ROS signaling induce stress responses in an age-dependent manner, and the age-dependent alteration in the RRTF1 function might be important for plants' acclimation to the stress environment.