IDENTIFICATION AND MOLECULAR ANALYSIS OF TRANSGENIC POTATO CHROMOSOMES TRANSFERRED TO TOMATO THROUGH MICROPROTOPLAST FUSION

Results are reported on the integration sites and copy number of alien marker genes neomycin phosphotransferase II (nptII) and beta-glucuron idase (uidA), introduced into diploid potato Solanum tuberosum through transformation by Agrobacterium tumefaciens. Also, the transgenic pot ato chromosomes 3 and 5 harbouring the nptII and uidA genes, which wer e transferred to tomato (wild species Lycopersicon peruvianum) by micr oprotoplast fusion, as revealed by genomic in situ hybridization (GISH ), were identified by RFLP analysis using chromosome-specific markers. The data revealed three integration sites in the donor potato genome, each containing the uidA gene, and two also harbouring the nptII gene . Analysis of monosomic-addition hybrid plants obtained after micropro toplast fusion showed that each of these three integration sites is lo cated on a different potato chromosome. The microprotoplast hybrid pla nts contained only the chromosomes that carried the selectable gene np tII. The data on sexual transmission of the donor potato chromosome ca rrying the uidA and nptII genes were obtained by analysing the first b ackcross progeny (BC1) derived from crossing a monosomic-addition hybr id plant to tomato (L. peruvianum). The glucuronidase (GUS) assay and PCR analysis using primers for the uidA gene indicated the presence of the potato chromosome in GUS-positive and its absence in GUS-negative BC1 plants. RFLP analysis confirmed sexual transmission of the potato chromosome carrying the nptII and uidA genes to the BC1 plants. A few BC1 plants contained the nptII and uidA genes in the absence of the p otato additional chromosome, indicating that the marker genes were int egrated into the tomato genome. The potential applications of the tran sfer of alien chromosomes and genes by microprotoplast fusion techniqu e are discussed.