OsPRX2 contributes to stomatal closure and improves potassium deficiency tolerance in rice.

Peroxiredoxins (Prxs) which are thiol-based peroxidases have been implicated in the toxic reduction and intracellular concentration regulation of hydrogen peroxide. In Arabidopsis thaliana At2-CysPrxB (At5g06290) has been demonstrated to be essential in maintaining the water-water cycle for proper HO scavenging. Although the mechanisms of 2-Cys Prxs have been extensively studied in Arabidopsis thaliana, the function of 2-Cys Prxs in rice is unclear. In this study, a rice homologue gene of At2-CysPrxB, OsPRX2 was investigated aiming to characterize the effect of 2-Cys Prxs on the K-deficiency tolerance in rice. We found that OsPRX2 was localized in the chloroplast. Overexpressed OsPRX2 causes the stomatal closing and K-deficiency tolerance increasing, while knockout of OsPRX2 lead to serious defects in leaves phenotype and the stomatal opening under the K-deficiency tolerance. Detection of K accumulation, antioxidant activity of transgenic plants under the starvation of potassium, further confirmed that OsPRX2 is a potential target for engineering plants with improved potassium deficiency tolerance.