RESISTANCE TO ACNU INDUCED TOXICITY IN TRANSGENIC TOBACCO SUSPENSION-CULTURES WITH ADA GENE TRANSFERRED FROM ESCHERICHIA-COLI

The protein coding region of the E. coli DNA repair gene ada combined with the CaMV 35S promoter has been transferred to tobacco by means of Agrobacterium tumefaciens Ti plasmid. In transgenic plants having the ada gene in a sense orientation, detectable amounts of O6-alkylguanin e-DNA-alkyltransferase has been found whereas in non-transformed plant s this activity is absent. Cell suspension cultures derived from the f ormer plants showed lower sensitivity to the toxic (growth inhibiting) effects of the bifunctional alkylating agent 1-nitroso-3-(aminomethyl -1,3-diazinylo)-methylurea compared with cell cultures derived from a control non-transformed plant or from transgenic plants harbouring the ada gene in an opposite, non-sense orientation.