Drought stress limits the productivity of plants. Transcription factors play important roles in drought stress tolerance. However, the mechanism of drought stress tolerance is not fully understood. The C2H2-type zinc finger transcription factor of Arabidopsis thaliana 6 (ZAT6) participates abiotic stress tolerance. In the present investigation, the function of transcription factor ZAT6 in drought stress tolerance was examined. Cells of rice (Oryza sativa L.) and white pine (Pinus strobes L.) overexpressing ZAT6 were generated using Agrobacterium-mediated genetic transformation. Physiological analysis of transgenic cell lines demonstrated that overexpression of ZAT6 increased tolerance to drought stress by decreasing lipid peroxidation and increasing the activities of antioxidant enzymes including ascorbate peroxidase (APOX), peroxidase (POD), catalase (CAT), and polyphenol oxidase (PPO). In rice cells, ZAT6 also enhanced transcription of Ca2+-dependent protein kinase genes OsCPK6 and OsCPK26 under drought stress. Altogether, our results suggest that overexpression of ZAT6 enhanced drought stress tolerance by increasing antioxidant enzyme activity and increasing transcription of Ca2+-dependent protein kinase in transgenic cells.

Keywords: Agrobacterium-mediated genetic transformation; C2H2-type zinc finger transcription factor of Arabidopsis thaliana 6; Ca2+-dependent protein kinase; Drought stress tolerance; Pinus