Highly efficient transformation and plant regeneration of tall fescue mediated by Agrobacterium tumefaciens.

An efficient and reproducible system hasbeen developed for the production of transgenic plantsin tall fescue (Festuca arundinacea Schreb.) using A.tumefaciens-mediated transformation. Two-months-oldsuspension cultures served as excellent explants fortransformation. The explants were inoculated with anA. tumefaciens strain EHA105 carrying a plasmidpDBA121 containing genes for hygromycinphosphotransferase (hpt) and phosphinotricinacetyltransferase (bar). The commercial herbicideBasta was used as a selective agent. Inclusion ofacetosyringone (ACS) 20 mg/L in the co-culture me-dium led to an increase in transformation efficiency.The efficiency of transformation was highly depen-dent on the genotype, the explant, the culture mediumand selective agent used. Tall fescue transformationefficiency is 2.85–10.9 plants per gram fresh weight(FW) of suspension cultures. This is much higher thanthe corresponding values reported before (2–5 plants).So far more than 300 transgenic plants have beenobtained, the fertility of some transgenic plants haddecreased. Stable integration and high expression ofthe transgenes were confirmed by PCR analysis andSouthern blot hybridization or herbicide Basta spray-ing test.