Characterization and Distribution of Tartrate Utilization Genes in the Grapevine Pathogen Agrobacterium vitis. J-Y Salomone. Department of Phytopathology, Plant Molecular Biology Institute of the C. N. R. S., 12 Rue du General Zimmer, 67084, Strasbourg, France. P. Crouzet, P. De Ruffray, and L. Otten Department of Phytopathology, Plant Molecular Biology Institute of the C. N. R. S., 12 Rue du General Zimmer, 67084, Strasbourg, France. MPMI 9:401-408. Accepted 15 March 1996. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1996.

Agrobacterium vitis is a common pathogen of grapevine. Most strains utilize tartrate, an abundant compound in grapevine. Strain AB3 carries two tartrate utilization (or TAR) regions: TAR-I (on the large pTrAB3 plasmid) and TAR-II (on the AB3 Ti plasmid). TAR-I and TAR-II were structurally and functionally analyzed and are similar to the TAR-III region from the tartrate utilization plasmid pTrAB4 of the nopaline-type A. vitis strain AB4 (Crouzet and Otten, J. Bacteriol. 1995, 177:6518-6526). The minimal tartrate utilization region of TAR-I contains four genes (ttuA-ttuD). The ttuC gene is homologous to the tartrate dehydrogenase gene from Pseudomonas putida. Outside the minimal region a second ttuC-like gene is found (ttuC) which is transcribed and complements a ttuC mutant. Most grapevine isolates carry one or two of the three characterized TAR regions and show a considerable degree of polymorphism around these regions