Abstract: In order to improve stress tolerance of turf-type tall fescue (Festuca arundinacea Schreb.), Agrobacterium tumefaciens strain EHA105 carrying plasmid pCMD containing stress tolerance-related CBF1 gene from Arabidopsis thaliana was used to transform mature seeds-derived embryogenic calli of four tested cultivars. One hundred and twelve transgenic plants from thirty-two independent lines were regenerated, which were confirmed by histochemical detection of GUS activity, PCR assay and Southern hybridization analysis. The transformation frequency ranged from 0.92% to 2.87% with apparent differences among the cultivars. Stress tolerance of transgenic plants were enhanced, which was testified by the facts that the transgenic plants had distinct growth superiority and significantly higher survival rate than non-transformed ones under high salt and high osmotic stresses, and that the relative electronic conductivity of in vitro leaves treated with low and high temperatures, dehydration and high salt stresses was 25%-30% lower in transgenic plants than in control plant. In addition, it was observed that growth of transgenic plants was inhibited due to constituent overexpression of CBF1 gene under normal environmental conditions.

Key words: Tall fescue (Festuca arundinacea Schreb.), Agrobacterium tumefaciens, Genetic transformation, CBF1 gene, Stress tolerance