Twentyg of plant genomic DNA was digested with BglII restrictionendonuclease, which cleaves at one end of the rstB gene to esti-mate insertion copy numbers of the transgene in the plant genome.The enzyme digestion products were separated in a 0.9% (w/v)agarose gel and blotted onto Hybond-N+nylon membrane (Amer-sham Pharmacia Biotech, Piscataway, NJ, USA)