Induction, selection and isolation of auxin heterotrophic and auxin-resistant mutants from cultured crown gall cells irradiated with gamma rays

Cultured crown gall cells were irradiated with gamma rays to induce mutation in indoleacetic acid biosynthesis. The irradiated cells were plated on a selection medium which contained auxin. Mutant cells adapted to selection media were characterized as auxin-heterotrophic and auxin-resistant cell lines. The auxin-heterotrophic mutants contained little auxin, whereas the auxin-resistant and -autotrophic mutants contained large amounts of auxin even when cultured with 0.3 ppm of 2,4-dichlorophenoxyacetic acid. Each mutant cell line contained as much octopine as its parental cells. The mutation rate was calculated as in the order of 10-8. (author)