Cysteine synthase gene from rice (Oryza sativa cv. Nipponbare) encoding cytosolic isoform (res1) and serine acetyltransferase gene from Arabidopsis thaliana encoding plastid isoform (SATI) were transformed into Pakbung (Ipomoea aquatiea Forsk.) using Agrobaeterium tumefaciens EHA 101 harbouring plasmid pBIH I-IG(SX)-SATl -resl. From 3, 125 cotyledon explants, 523 regenerated shoots were obtained and 2 shoots were tolerated to 25 µg/ml hygromycin. Confirmation for the existance of res 1 and SAT1 in the genome of hygromycin resistant shoot was done by polymerase chain reaction. The 2 hygromycin resistant shoots gave a PCR product coinciding with the res 1 and the SATl. Cysteine synthase activity and serine acetyltransferase activity of the 2 transformants (No. I and No.2) were 5.20, 5.03 times and 2.17, 2.14 times, respectively higher than those of the wild type. Sulfate absorption efficiency of the 2 transformants (No.1 and No.2) was 4.48, 3.45 times higher than those of the wild type
