A Jasmonate ZIM-domain subfamily protein regulates drought tolerance via modulating the stomatal density in rice.

Abstract

Stomata, which serve as vital interfaces between plants and the atmosphere, are closely associated with drought adaptation via changes in stomatal density. In this study, we identified DROUGHT TOLERANCE 3 (DT3) as a key gene that regulates drought tolerance in rice by controlling stomatal density. DT3 belongs to the JAZ (Jasmonate ZIM-domain) subfamily of the TIFY gene family in rice. DT3 interacts with the basic helix-loop-helix (bHLH) transcription factor bHLH048 and disrupts its suppression of the abscisic acid (ABA) biosynthesis gene 9-CIS-EPOXYCAROTENOID DIOXYGENASE 2 (NCED2). As a result, elevated expression of NCED2 increases endogenous ABA levels, which reduces stomatal density and enhances drought tolerance in rice. Moreover, the natural variation in the promoter region of DT3 contributed to the various expression levels of DT3. Therefore, manipulating the DT3-bHLH048-NCED2-ABA pathway represents a promising climate-adaptive strategy to improve drought tolerance in rice.