Abstract: Expression vector containing a chitinase gene and some regulatory sequences was in this reseach. Using the Ri plasmid of Agobacterium. rhizogenes, the chitinase gene was introduced into tobacco, three cultivars of tobacco. Seven plants were proved of be transformed tobacco by PCR detection, by dot blot hybridization. The result sussgested that the construction of the expression vector is successful and the chitinase gene had integrated into tobacco genome.

Key words: expression vector, chitinase gene, tobacco, Ri plasmid