Gleta Carswell

Selection of transformed protoplast-derived Zea mays colonies with phosphinothricin and a novel assay using the pH indicator chlorophenol red

Phosphinothricin (PPT) inhibits glutamine synthetase in plant cells, resulting in an accumulation of ammonia that can be toxic. Bar, from Streptomyces hygroscopicus is a gene that codes for phosphinothricin acetyl-transferase, an enzyme that detoxifies PPT by acetylation. We used polyethylene-glycol-mediated transformation to introduce bar into protoplasts of maize (Zea mays L.). With a novel assay utilizing the pH indicator chlorophenol red we identified transformants after only two to four weeks of selection on PPT.

Direct gene transfer via polyethylene glycol

Polyethylene glycol can be used to induce DNA uptake into plant protoplasts. Procedures for isolation, culture and transformation ofN. tabacum protoplasts are described and can be adapted for other dicot and monocot species. Criteria for proof of transformation are discussed.