Overexpression of maize chloride channel gene ZmCLC-d in Arabidopsis thaliana improved its stress resistance

In plant cells, anion channels and transporters are essential for key functions. Members of the chloride channel (CLC) family located in intracellular organelles are required for anion accumulation, pH adjustment, and salt tolerance. Here, we cloned a maize (Zea mays L.) CLC gene, named ZmCLC-d, and found that its transcription was up-regulated under cold, drought, salt, and heat stresses, and after hydrogen peroxide (H₂O₂) and abscisic acid (ABA) treatments. The overexpression of ZmCLC-d in Arabidopsis conferred tolerance to cold, drought, and salt stresses; this tolerance was primarily displayed by an increased germination rate, root length, plant survival rate, antioxidant enzyme (catalase, peroxidase, and superoxide dismutase) activities, and a reduced accumulation of Cl⁻in transgenic plants as compared with wild type (WT) plants. The accumulation of H₂O₂and superoxide anion in leaves of the ZmCLC-d-overexpressing plants is much less than that of the WT plants. The expressions of some stress related genes, such as CBF1, CBF2, CBF3, DREB2A, and RCI2A, increased to a greater extent in the ZmCLC-d-overexpressing plants than in the WT. Our results strongly suggest that ZmCLC-d played an important role in stress tolerance.