OsASR5 enhances drought tolerance through a stomatal closure pathway associated with ABA and H₂O₂ signalling in rice

Abstract

SummaryDrought is one of the major abiotic stresses that directly implicate plant growth and crop productivity. Although many genes in response to drought stress have been identified, genetic improvement to drought resistance especially in food crops is showing relatively slow progress worldwide. Here, we reported the isolation of abscisic acid, stress and ripening (ASR) genes from upland rice variety, IRAT109 (Oryza sativa L. ssp. japonica), and demonstrated that overexpression of OsASR5 enhanced osmotic tolerance in Escherichia coli and drought tolerance in Arabidopsis and rice by regulating leaf water status under drought stress conditions. Moreover, overexpression of OsASR5 in rice increased endogenous ABA level and showed hypersensitive to exogenous ABA treatment at both germination and postgermination stages. The production of H2O2, a second messenger for the induction of stomatal closure in response to ABA, was activated in overexpression plants under drought stress conditions, consequently, increased stomatal closure and decreased stomatal conductance. In contrast, the loss‐of‐function mutant, osasr5, showed sensitivity to drought stress with lower relative water content under drought stress conditions. Further studies demonstrated that OsASR5 functioned as chaperone‐like protein and interacted with stress‐related HSP40 and 2OG‐Fe (II) oxygenase domain containing proteins in yeast and plants. Taken together, we suggest that OsASR5 plays multiple roles in response to drought stress by regulating ABA biosynthesis, promoting stomatal closure, as well as acting as chaperone‐like protein that possibly prevents drought stress‐related proteins from inactivation.

PeCHYR1, a ubiquitin E3 ligase from Populus euphratica, enhances drought tolerance via ABA‐induced stomatal closure by ROS production in Populus

“…Previous studies have indicated that plants regulate ABA‐induced stomatal closure by ROS accumulation (Bright et al ., ; Hua et al ., ; Li et al ., ). H 2 O 2 is a ROS that acts as a second messenger in ABA signalling in guard cells (Bright et al ., ; Dietz et al ., ; Kohler et al ., ).…”

“…Previous studies have indicated that AtRbohF can be phosphorylated by OST1 (an ABA‐induced SnRK2.6 protein kinase) (Joshi‐Saha et al ., ; Sirichandra et al ., ; Wege et al ., ). H 2 O 2 is a reactive oxygen species (ROS) that acts as a major signalling molecule in the ABA response pathway in guard cells (Bright et al ., ; Li et al ., ). High concentrations of ROS lead to cell injury or even hypersensitive cell death, whereas low concentrations of ROS function as developmental signals, controlling all aspects of plant biology (Ahmad et al ., ; Dietz et al ., ; Huang et al ., ; Karuppanapandian et al ., ; Pitzschke et al ., ).…”

“…High concentrations of ROS lead to cell injury or even hypersensitive cell death, whereas low concentrations of ROS function as developmental signals, controlling all aspects of plant biology (Ahmad et al ., ; Dietz et al ., ; Huang et al ., ; Karuppanapandian et al ., ; Pitzschke et al ., ). OsASR5 and DCA1, which enhance drought tolerance in rice, control stomatal closure by adjusting the concentration of H 2 O 2 (Cui et al ., ; Li et al ., ) . GHR1 modulates stomatal movement associated with H 2 O 2 signalling in Arabidopsis (Hua et al ., ).…”

“…The SNAC1‐targeted gene OsSRO1c positively controls H 2 O 2 ‐induced stomatal closure by regulating hydrogen peroxide level in rice, and the E3 ligase OsHTAS can promote heat tolerance by modulating H 2 O 2 ‐induced stomatal closure in rice (Liu et al ., ; You et al ., ). However, 35S: OsASR5 plants were more sensitive to exogenous ABA treatment, activating the production of H 2 O 2 (Li et al ., ).…”

“…To adapt to hostile environments, plants have developed intrinsic mechanisms to mitigate drought stress, such as closing stomata, reducing transpiration, generating abscisic acid (ABA) and accumulating hydrogen peroxide (H 2 O 2 ) (Dietz et al ., ; Zhu, ). ABA‐induced stomatal closure is a defensive action that is usually accompanied by the production of H 2 O 2 (Li et al ., ; Zhang et al ., ). NADPH oxidase (RbohF) can generate H 2 O 2 in guard cells, which crucially modulates ABA‐induced stomatal closure and plant drought tolerance (Gudesblat et al ., ; Kolla et al ., ; Ma et al ., ).…”