Improved in vitro selection of nitrate reductase-deficient mutants of Nicotiana plumbaginifolia.

The use of increasing knowledge on regulation of nitrate reductase activity in Nicotiana cell cultures is the basis for the described optimization of in vitro selection for nitrate reductase-deficient mutants by screening for chlorate resistance. Selection was carried out on haploid mesophyll protoplast-derived cell cultures of Nicotiana plumbaginifolia. It is demonstrated that revised selection results in high variant detectability and increased variant confirmability in comparison with the hitherto used selection scheme.