TRANSGENIC TOMATO LINES CONTAINING DS ELEMENTS AT DEFINED GENOMIC - POSITIONS AS TOOLS FOR TARGETED TRANSPOSON TAGGING

We have introduced a genetically marked Dissociation transposable element (Ds(HPT)) into tomato (Lycopersicon esculentum) by Agrobacterium tumefaciens-mediated transformation. Probes for the flanking regions of the T-DNA and transposed Ds(HPT) elements were obtained with the inverse polymerase chain reaction (IPCR) technique and used in RFLP linkage analyses. The RFLP map location of 11 T-DNAs carrying Ds(HPT) was determined. The T-DNAs are distributed on 7 of the 12 tomato chromosomes. To explore the feasibility of gene tagging strategies in tomato using Ds(HPT), we examined the genomic distribution of Ds(HPT) receptor sites relative to the location of two different, but very closely linked, T-DNA insertion sites. After crosses with plants expressing Ac transposase, the hygromycin phosphotransferase (HPT) marker on the Ds element and the excision markers beta-glucuronidase (GUS) and Basta resistance (BAR) facilitated the identification of plants bearing germinally transposed Ds(HPT) elements. RFLP mapping of 21 transposed Ds(HPT) elements originating from the two different T-DNA insertions revealed distinct patterns of reintegration sites.