Abstract
We developed a positive detection system of mutation occurring on chromosomal DNA in higher plant. Plasmid pML4 carrying E. coli rpsL gene, a target gene for mutagenesis was introduced into plant. After the transgenic plant was treated with mutagen. pML4 was rescued from plant genome. Streptomycin (Sm)-resistant E. coli transformed with rescued pML4 was spread on LB agar medium containing Sm. Only E. coli cells containing pML4 carrying an inactivated rpsL by mutation are able to grow on the medium containing Sm because mutated rpsL gene is insensitive to Sm. Thus the newly developed system is a valuable for detection and analysis of mutation occurring on chromosomal DNA in higher plants. Arabidopsis thaliana was transformed with pML4, which was carried by pCGN5138 via Agrobacterium by floral dip method. Typical base change mutations, G:C to A:T transition, were found in the plants grown from transgenic Arabidopsis seeds treated with EMS. The type of base change preferred occurring on guanine at 5'-PuG-3' sequence. Plants on the earth continuously irradiated with solar UV and whereas possess UV-protecting systems such as photoreactivation and UV-absorbing pigments. We are investigating whether UV-induced mutation in Arabidopsis is detected or not.
