Overexpression of Arabidopsis ICE1 improves cold tolerance in transgenic Zoysia japonica

Abstract

ICE1 (Inducer of CBF Expression1), is a regulator of cold-induced transcriptome, which plays an important role during cold tolerance signal pathways in Arabidopsis thaliana. To enhance the cold tolerance of Zoysia Japonica, one of the perennial warm-season turfgrass, the ICE1 gene was cloned by RT-PCR and constructed into the plant expression vector pIG2 modified from pC3301. The ICE1 was under the control of ubiquitin promoter and successfully transformed into Zoysia Japonica wild type callus and Arabidopsis thaliana ecotype Columbia (Col-0) by the Agrobacterium-mediated transformation method respectively. After cold treatment at -8℃ for 2 hours and 5 days recovery, The transgenic lines of Arabidopsis pIG2-ICE1-3, pIG2-ICE1-5 showed a higher survival rate 84.5% and 86.9% than the wild type 73.2%. Furthermore, the transgenic lines showed big leaves compared with wild type. RT-PCR and Southern blot analysis of 15 PPT resistant Zoysia japonica transgenic lines suggested that ICE1 had been integrated into Zoysia japonica genome successfully. The transgenic plants showed higher ICE1 expression level compared with wild type by Real time qRT-PCR. Overexpression of ICE1 both in transgenic Zoysia Japonica and Arabidopsis showed higher proline content, less MDA content, higher activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT). All of this indicated that overexpression of ICE1 gene improved cold tolerance of Zoysia japonica and Arabidopsis at low temperatures.