Improving Plant Tolerance to Drought Stress By Overexpression of ZmDBP2 Gene in Switchgrass.

Drought stress is a major limiting factor for plant growth and development in many regions. Here we introduced ZmDBP2 gene into switchgrass by Agrobacterium-mediated transformation. The expression of the ZmDBP2 in transgenic plants were tested by PCR, RT-PCR, and southern blot techniques. The transgenic lines overexpressing ZmDBP2 gene exhibited more tillers, smaller leaf blades, and delayed flowering time when compared to non-transgenic plants. The transgenic plants had greater net photosynthetic rate, less stomatal conductance and transpiration rate than the non-transgenic ones under drought stress conditions. Overexpression of ZmDBP2 gene induced a shift of hormonal balance which was associated with water conservation and delaying senescence under drought stress conditions. Gene expression analysis data showed that the transgenic plants had higher level of antioxidant gene expression than non-transgenic ones in response to drought stress. The results of this study suggest that overexpression of ZmDBP2 gene may improve switchgrass drought tolerance by regulating hormonal and antioxidant metabolism.