FORMATION OF DELETIONAL DERIVATIVES OF THE TI-PLASMID PGV3850 IN A CONJUGATIVE TRANSFER FROM AGROBACTERIUM-TUMEFACIENS TO ESCHERICHIA-COLI

The process of the transfer of the Ti-plasmid vector pGV3850 with the plasmid pBR322 inserted into the T-DNA region from Agrobacterium tumef aciens to a nonplasmid strain of Escherichia call was studied The tran sferred Ti-plasmid was found to be exposed to deletions and formed a w ide range of derivatives with a size ranging from 3-4 kb to 50 kb, mai ntained in E, coli due to ColE1-replicon. The Ti-plasmid is also inser ted into the chromosome of the recipient bacterium with at least a 100 -fold lower frequency than the formation of deletional derivatives. It was shown that the induction of vir genes controlling the transfer of T-DNA into plants has no appreciable effect on the efficiency of obta ining trasconjugates in mating with E. coli. The deletion of the gener ic material of megaplasmids with the inserted functional site OriV Col E1, as a result of the conjugative transfer from cells of different ba cteria to the cells of E, coli, was proposed for molecular cloning.