Structure and function of a conserved DNA region coding for tartrate utilization in Agrobacterium vitis.

Three tartrate utilization regions from Agrobacterium vitis strains involved in host specificity have been compared, to clearly define the borders of these regions and eventually identify specific sequences that could provide a mechanism of duplication of this region. A 10.8-kb conserved DNA fragment called the TAR element, found in different genetic contexts, was defined. A comparison of the two tartrate dehydrogenase genes (ttuC and ttuC') in each of the three TAR elements suggests that these genes co-evolve.