Abstract: We describe our construction of a plant expression vector, which contained an UDP-glucose pyrophosphorylase gene and an anti-sense 4-coumarate: CoA ligase gene. The vector was transferred by use of Agrobacterium tumefaciens into tobacco. Results of PCR and Southern blot analysis indicated that both genes were integrated into the tobacco genome successfully. Holocellulose content was increased and Klason lignin content significantly reduced, which illustrated that the two genes were expressed effectively in the tobacco genome.