Abstract: A plant transformation vector for transforming host plant cells with a chimeric selectable marker gene is disclosed. The gene includes, operatively linked in sequence in a 5′ to 3′ direction, (i) a DNA promoter sequence from the rice beta-glucanase 9 (gns9) gene; (ii) a selectable marker gene, and (iii) a 3′ untranslated terminator region. Also disclosed are a vector pair containing the transformation vector, a method of obtaining transformed monocots whose seeds produce a selected heterologous protein during sed germination, and a plant whose cells are transformed with the chimeric selectable marker gene.

Abstract: A plant transformation expression cassette for transforming host plant cells with a selectable marker gene is disclosed. The cassette includes, operatively linked in sequence in a 5′ to 3′ direction, (i) a DNA promoter sequence from the rice beta-glucanase 9 (gns9) gene; (ii) a selectable marker gene, and (iii) a 3′ untranslated terminator region. Also disclosed are a expression cassette pair containing the transformation vector, a method of obtaining transformed monocots whose seeds produce a selected heterologous protein during sed germination, and a plant whose cells are transformed with the chimeric selectable marker gene.

Abstract: A method for producing .alpha..sub.1 -antitrypsin (AAT) in plant cells is disclosed. Monocot plant cells transformed with an AAT coding sequence are cultivated under conditions efficient for protein expression and secretion. Also disclosed are a codon-optimized AAT coding sequence that is efficiently translated in plant cell culture and a novel AAT protein having the glycosylation pattern characteristic of plant cells and suitable for therapeutic use in humans.

Abstract: A method for stably transforming barley from mature barley seeds as starting material is disclosed. The method involves germinating mature barley seeds until early shoot development occurs, exposing scutellar or embryo tissue cells on the embryo side of germinated seeds, and introducing foreign DNA into the cells. The cells are initially grown under conditions that allow expression of a selectable marker introduced with the foreign DNA, then on a callus-growth medium effective to suppress callus formation in the absence of the selectable marker. Successfully transformed calli can be cultured in suspension to obtain a desired foreign protein, or regenerated into plants, to obtain the foreign protein from the transformed plants, e.g., germinated seeds.

Abstract: A chimeric gene for use in producing a mature protein in secreted form by stably transformed plant cells is disclosed. The gene includes a DNA coding sequence encoding a fusion protein having an (i) N-terminal moiety corresponding to the portion of the rice .alpha.-amylase signal sequence peptide identified by SEQ ID: 1 and, (ii) immediately adjacent the C-terminal amino acid of said portion, a protein moiety corresponding to the protein to be produced. Also disclosed are a fusion protein encoded by the gene, and a method of producing a mature protein in secreted form by plant cells.