ZmCBF3 overexpression improves tolerance to abiotic stress in transgenic rice (Oryza sativa) without yield penalty.

Plant productivity is greatly affected by environmental stresses such as drought, salt, and freezing. We previously described a C-repeat binding transcription factor from maize (ZmCBF3) that was upregulated by both abscisic acid and low-temperature and actively expressed during embryogenesis. To understand the stress response in rice, transgenic ZmCBF3 rice with ubiquitin promoter was developed. T3 generation was planted and analyzed. The results showed that overexpression of ZmCBF3 in rice did not cause growth retardation under normal growth conditions with improved tolerance to drought, high-salt, and low-temperature stresses. Moreover, the transgenic rice grain yield was similar to wild type plants under normal conditions. The transgenic plants showed enhanced survival rate and reduced malondialdehyde content and relative conductivity under drought, salt, and low-temperature stresses. ZmCBF3 overexpression in transgenic rice increased the transcript levels of stress-induced genes and enhanced the tolerance to drought, salt, and low-temperature stresses.