Herbicide Tolerant - Basta

Basta is the trade name for a different, non-selective herbicide, built around the chemical compound phosphinothricin (PPT). The corresponding tolerance gene, PPT, was originally isolated from the alfalfa plant Medicago sativa; its mechanism is to inhibit glutamine synthase, an enzyme central to how a plant assimilates ammonia into usable nitrogen-containing compounds - block that enzyme, and normal nitrogen metabolism collapses. Introducing this PPT gene into tobacco produced a transgenic tobacco plant genuinely resistant to PPT/Basta, proving the concept worked. A closely related but separately sourced version of essentially the same resistance mechanism was later isolated from a different organism entirely - the soil bacterium Streptomyces hygroscopicus - carrying a gene called 'bar', which encodes the enzyme phosphinot …