Abstract
We showed that reactive oxygen species (ROS) are required for the biosynthetic substrate and regulator of growth and development, but little is known about the regulatory mechanism. Thus we screened the Arabidopsis mutants having high steady-state ROS levels, one of which proved defective in the linolenic acid (18:3) synthesis. This mutant flowered earlier than the wild-type under long-day/weak-light conditions. Overexpression of the identified gene increased high 18:3 levels, retarded flowering and reduced ROS levels. These suggest that 18:3 suppresses ROS levels and flowering. In the wild-type plant, flowering was promoted by the ROS-generating paraquat and suppressed by the ROS-generation-suppressive anaerobic conditions, but not in the mutant. Considering the ROS-susceptible active methylene group in 18:3, it is concluded that 18:3 is one target of ROS to regulate any flowering determinant. Animal lifespan positively correlates to 18:3 contents. The present data imply the potential lifespan control using the molecular-genetic techniques.
