a new method for the identification of useful promoters is disclosed . the method is capable of identifying bacterial promoters sensitive to a particular cellular insult and may be modified to identify promoters sensitive to herbicides and crop protection chemicals . constructs comprising promoters upstream of a luminescent reporter genes are placed in transformed hosts . transformants grown in liquid media to a predetermined growth stage and contacted with a cellular insult are assessed for regulatory region activity by measurement of the resulting change in bioluminesence . the method is able to identify promoters undetectable by standard methods .