T-DNA INSERTION MUTAGENESIS IN ARABIDOPSIS - PROSPECTS AND PERSPECTIVES

Approximately 13 000 independent transformants of Arabidopsis have been generated utilising the Agrobacterium-mediated seed infection/transformation procedure. The average number of functional independent T-DNA insertion events per transformed line is 1.5, thus constituting a population with 19 500 independent inserts. These transformed lines have been screened under two environmental regimes for visible alterations in phenotype. In one screen the lines were grown under greenhouse conditions and examined at weekly intervals. In the second, seeds from each line were plated under axenic conditions in vertically oriented square petri plates and examined 4 and 9 days after germination. The mutants observed were placed into 7 distinct phenotypic classes: seedling-lethal, size variant, reduced-fertility, pigment defect, embryo-defective, dramatic morphological, and physiological. The mutational spectrum of the first 8000 transformed lines has been reported earlier. The mutational spectrum for a further 5000 transformed lines is reported here and, with several notable exceptions, is similar to that observed previously.