Production of Transgenic Tall Fescue Plants with Enhanced Stress Tolerances by Agrobacterium tumefaciens-Mediated Transformation

In order to improve stress tolerances of turf-type tall fescue (Festuca arundinacea Schreb.), Agrobacterium tumefaciensstrain EHA105 carrying plasmid pCMD containing stress tolerance-related CBF1 gene from Arabidopsis thaliana wasused to transform mature seeds-derived embryogenic calli of four cultivars. A total of 112 transgenic plants were regeneratedfrom 32 independent lines and verified by histochemical detection of GUS activity, PCR assay and Southern hybridizationanalysis. The transformation frequency ranged from 0.92 to 2.87% with apparent differences among the cultivars. Stresstolerances of transgenic plants were enhanced, which was shown by the facts that transgenic plants had distinct growthsuperiority and significantly higher survival rate than non-transformed ones under high salinity and high osmosis stresses,and that relative electronic conductivity of in vitro leaves treated with low and high temperatures, dehydration and highsalinity stresses was 25-30% lower in transgenic plants than in control plants. In addition, it was observed that growth oftransgenic plants was inhibited due to constitutive overexpression of CBF1 gene under normal environmental conditions.