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

We have introduced a genetically marked Dissociation transposable elem ent (Ds(HPT)) into tomato (Lycopersicon esculentum) by Agrobacterium t umefaciens-mediated transformation. Probes for the flanking regions of the T-DNA and transposed Ds(HPT) elements were obtained with the inve rse polymerase chain reaction (IPCR) technique and used in RFLP linkag e analyses. The RFLP map location of 11 T-DNAs carrying Ds(HPT) was de termined. The T-DNAs are distributed on 7 of the 12 tomato chromosomes . To explore the feasibility of gene tagging strategies in tomato usin g Ds(HPT), we examined the genomic distribution of Ds(HPT) receptor si tes relative to the location of two different, but very closely linked , T-DNA insertion sites. After crosses with plants expressing Ac trans posase, the hygromycin phosphotransferase (HPT) marker on the Ds eleme nt and the excision markers beta-glucuronidase (GUS) and Basta resista nce (BAR) facilitated the identification of plants bearing germinally transposed Ds(HPT) elements. RFLP mapping of 21 transposed Ds(HPT) ele ments originating from the two different T-DNA insertions revealed dis tinct patterns of reintegration sites.