Design and evolution of the tetracycline repressor into sulfonylurea herbicide-responsive gene switches for field crops (opens in new tab)

Chemically inducible expression systems enable transgene expression regulation in response to external small molecules. Tetracycline repressor (TetR)-based gene switches work in plants, but antibiotics are neither approved nor advisable for crop use. Here we report engineering of TetR mutants that respond to approved sulfonylurea (SU) herbicides instead of antibiotics. Designed variants show low-nanomolar EC50 values for ethametsulfuron-methyl (Es) or chlorsulfuron and tightly bind the Tet op...