Improvement of arabidopsis mutant screens based on luciferase imaging in planta

A mutant screen was developed to isolate Arabidopsis thaliana mutants affected in the signaling pathway of phytochrome A. Mutagenized transgenic seedlings were screened for deregulated expression of a chalcone synthase promoter fused to luciferase after etiolated tissue was treated with far-red light. The efficiencies of two types of cameras used for imaging the mutant population and for isolating individual mutants were compared. The cooled CCD camera performed more efficiently than the intensified CCD camera, and when combined to a powerful analysis software, it allowed rapid and accurate selection of putative mutants. A description of image-analysis automation is presented together with theoretical and experimental comparisons of the two types of cameras.