NADPH oxidase AtrbohD and AtrbohF genes function in ROS‐dependent ABA signaling in Arabidopsis

Identification of two partially redundant Arabidopsis guard cell‐expressed NADPH oxidase catalytic subunit genes, AtrbohD and atrbohF, are reported, providing direct molecular genetic and cell biological evidence that ROS are rate‐limiting second messengers in ABA signaling, and that the AtrbOHD and AtrabohF NADPH oxidationases function in guard cell ABA signal transduction.