The present invention relates to the production of a non-transgenic plantresistant or tolerant to a herbicide of the phosphonomethylglycine family,e.g., glyphosate. The present invention also relates to the use of arecombinagenic oligonucleobase to make a desired mutation in the chromosomalor episomal sequences of a plant in the gene encoding for 5-enolpyruvylshikimate-3-phos.rho.hate synthase (EPSPS). The mutated protein, whichsubstantially maintains the catalytic activity of the wild-type protein,allows for increased resistance or tolerance of the plant to a herbicide ofthe phosphonomethylglycine family, and allows for the substantially normalgrowth or development of the plant, its organs, tissues or cells as comparedto the wild-type plant irrespective of the presence or absence of theherbicide. Additionally the present invention relates to mutant E. coli cellsthat contain mutated EPSPS genes.
