Abstract: The CAS genes were analyzed by bioinformatics methods and over-expression vectors of CAS genes were constructed. Bioinformatics analysis show that CYS -C1 and CYS -D1 have ten exons and nine introns，while CYS -D2 has nine exons and eight intron. CYS -C1 and CYS -D1 locate at chromosome 3 while CYS -D2 locates at chromosome 5. Furthermore，the amino acid sequences of CAS genes share a high similarity. However，CYS -C1 is basic protein and functions at mitochondria，whereas CYS -D1 and CYS -D2 are acidic protein and function at cytoplasm. The over- expression vectors of pBI121- 35SCYS-C1 ，pBI121-35S- CYS -D1 and pBI121-35S- CYS -D2 were constructed，and the recombinant plasmids were transformed into agrobacterium GV3101.

Key words: arabidopsis, cyanoalanine synthase（CAS）, over-expression vector, bioinformatics