Ten micrograms of genomic DNA or 10 ng of plasmid, was digested
with EcoRI. The digested DNA was separated with a 0.7% agarose gel,
transferred to a positively charged nylon membrane (GE Healthcare,
USA). Hybridization probe was prepared by amplifying a 493-bp fragment
of the nptII gene from the pBI-EGFP vector using the forward
primer 5′-GTCACTGAAGCGGGAAGGG-3′ and the reverse primer 5′-
CGGCGATACCGTAAAGCAC-3′. Probe labeling, hybridization (47 °C)
and chemiluminescent detection were performed according to the instructions
in the DIG-High Prime DNA Labeling and Detection Starter
Kit II (Roche, Germany).