Expression of the cold acclimation-specific protein gene of medicago alfalfa freezing tolerance in tobacco

[Objective] The aim was to study the expression of cold resistant gene CAS19 of Gongnong No.2 Medicago sativa L. in tobacco. [Method] A pair of primers was designed according to nucleotide sequences of cold resistant gene CAS19 of M. sativa, and then RT-PCR was used to amplify the protein gene of CAS19, which was then cloned into pMD18-T vector and subcloned into expression vector PBI121. The recombination expression plasmid PBCAS was constructed. And then it was transferred into tobacco genome via Agrobacterium, and Southern-blotting analysis was used for detecting transgenic plants. [Result] CAS19 gene was integrated into the tobacco genome and highly expressed. [Conclusion] This study had provided theoretical basis for further exploring the expression mechanism of cold resistant gene CAS19 in tobacco.