Transgenic plants of tall fescue (Festuca arundinacea Schreb.) obtained by direct gene transfer to protoplasts.

Chimeric hygromycin phosphotransferase (hph) and phosphinothricin acetyltransferase (bar) genes were introduced, using polyethylene glycol treatment, into protoplasts isolated from embryogenic cell suspension cultures of tall fescue (Festuca arundinacea Schreb.), a graminaceous plant that is an important forage crop in temperate pastures. Colonies resistant to either 200 mg/l hygromycin or 100 mg/l phosphinothricin, respectively, were recovered upon selection using bead-type culture systems. Stable integration of the transgenes in the genomes of plants regenerated from resistant callus clones was shown by Southern hybridization analysis. In situ hybridization of a labeled transgene-probe to metaphase chromosomes is shown for one transgenic primary regenerant. Expression of the transgenes in mature plants was demonstrated by HPH enzyme assay or by phosphinothricin-herbicide spraying.