Ectopic Expression of AtCIPK23 Enhances Drought Tolerance Via Accumulating Less H2O2 in Transgenic Tobacco Plants

Drought is a major threat to agricultural crop growth and productivity. However, the molecular mechanism behind such effects remains largely unknown. Plant CBL (Calcineurin B-Like)-interacting protein kinases (CIPKs) are believed to play an important role in plant drought tolerance and signalling transduction. Here, we report the influence of a member of the CIPK family, AtCIPK23, in drought stress responses in tobacco. Transgenic tobacco plants over-expressing AtCIPK23 showed enhanced tolerance to drought stress compared with wild-type plants. After drought stress treatment, the survival rates and levels of chlorophyll, proline, and soluble sugar in three transgenic lines were significantly higher than those in WT plants. Additionally, in the transgenic plant lines the accumulation of H2O2 was lower, and the expression levels of NtSOD, NtCAT and NtAPX were higher compared with wild-type plants under drought stress. A quantitative RT-PCR analysis revealed that over-expression of AtCIPK23 in tobacco induced the expression of the NtDREB, NtLEA5 and NtCDPK2 genes. Therefore, AtCIPK23 perhaps is involved in the plant response to drought stress via regulating the expression of stress-related genes.