OPTIMIZING THE USE OF THE MAIZE TRANSPOSON AC FOR GENE ISOLATION IN DICOTYLEDONOUS PLANTS.

THERE IS A DEFINITE NEED IN CROP IMPROVEMENT FOR A METHOD TO ISOLATE PLANT GENES WHICH RELIES PRIMARILY ON PHENOTYPES.THE IDEA OF USING PLANT TRANSPOSONS IN SUCH A STRATEGY IS ATTRACTIVE BUT ITS EFFICIENT IMPLEMENTATION AWAITS A DETAILED INVESTIGATION INTO FACTORS WHICH MIGHT INFLUENCE TRANSPOSITION FREQUENCY. THE CORN TRANSPOSON AC (ACTIVATOR), WHICH HAS BEEN USED IN GENE ISOLATION IN CORN, IS KNOWN TO TRANSPOSE IN TOBACCO, BUT EXISTING SYSTEMS FOR MONITORING THE ACTIVITY OF THE TRANSPOSON ARE LIMITED BY THE ABSENCE OF ANY PHENOTYPE WHICH CAN BE EASILY SCORED IN WHOLE PLANTS. THIS POSES PROBLEMS IN ASSESSING THE EFFECTIVENESS OF SYSTEMS FOR GENE ISOLATION BASED ON TRANSPOSON MUTAGENESIS. WE HAVE ENGINEERED A USEFUL VISUAL ASSAY FOR AC TRANSPOSITION IN SEEDLINGS BASED ON SCORING SOMATIC EXCISIONS FROM A STREPTOMYCIN RESISTANCE GENE. WE PROPOSE TO CARRY OUT FURTHER STUDIES ON GENETIC AND OTHER FACTORS WHICH MIGHT INFLUENCE TRANSPOSITION FREQUENCY IN DICOTS IN ORDER TO REFINE PLANT TRANSPOSON TECHNOLOGY SO THAT IT CAN EFFECTIVELY BE USED FOR GENE ISOLATION IN THIS GROUP OF PLANTS.