Abstract: The plant expression vector containing human alpha-lactalbumin gene was constructed and its gene was transformed into tobacco using leaf disc mediated by Agrobacterium tumefaciens LBA 4404 as a vehicle. PCR and Southern blot analyses showed that human alpha-lactalbumin gene was integrated into the tobacco genome. RT-PCR and histochemical staining for GUS activity demonstrated that human alpha-lactalbumin gene was expressed in transgenic tobacco plants. Further analysis of the data indicated that the average of cysteine contents in 9 transgenic tobacco plants was greatly increased by 166.40% besides one of them which was increased by 318.02%

Key words: Human alpha-lactalbumin gene