LOCALIZATION OF DS-TRANSPOSON CONTAINING T-DNA INSERTS IN THE DIPLOIDTRANSGENIC POTATO - LINKAGE TO THE R1 RESISTANCE GENE AGAINST PHYTOPHTHORA-INFESTANS (MONT) DE BARY

The Dissociation transposable element (Ds) of maize containing NPTII w as introduced into the diploid potato (Solanum tuberosum) clone J91-64 00-A16 through Agrobacterium tumefaciens mediated transformation. Geno mic DNA sequences flanking the T-DNAs from 312 transformants were obta ined with inverse polymerase chain reaction or plasmid rescue techniqu es and used as probes for RFLP linkage analysis. The RFLP map location of 60 T-DNAs carrying Ds-NPTII was determined. The T-DNA distribution per chromosome and the relative distance between them appeared to be random. All 12 chromosomes have been covered with Ds-containing T-DNAs , potentially enabling tagging of any gene in the potato genome. The T -DNA insertions of two transformants, BET92-Ds-A16-259 and BET92-Ds-A1 6-416, were linked in repulsion to the position of the resistance gene R1 against Phytophthora infestans. After crossing BET92-Ds-A16-416 wi th a susceptible parent, 4 desired recombinants (Ds carrying T-DNA lin ked in coupling phase with the R1 gene) were discovered. These will be used for tagging the R1 gene. The efficiency of the pathway from the introduction to localization of T-DNAs is discussed.