Phylogenetic Relationships Between Agrobacterium vitis Isolates and Their Ti Plasmids. L. Otten. C.N.R.S. Institute of Plant Molecular Biology, Rue du General Zimmer 12, Strasbourg 67084, France. P. de Ruffray(1), E. A. Momol(2), M. T. Momol(2), and T. J. Burr(2). (1) C.N.R.S. Institute of Plant Molecular Biology, Rue du General Zimmer 12, Strasbourg 67084, France; (2) Department of Plant Pathology, Cornell University, Geneva, NY 14456-0462 U.S.A. MPMI 9:782-786. Accepted 17 September 1996. Copyright 1996 The American Phytopathological Society.

A collection of 76 Agrobacterium vitis isolates was analyzed by several molecular methods. PCR analysis of the 16S-23S intergenic spacer (IGS) region of the ribosomal DNA, restriction patterns of total DNA, and hybridization with different Ti plasmid probes enabled us to distinguish chromosomal and Ti plasmid characteristics. The various strains could be divided into several chromosomal groups based on IGS patterns. Each group was found to contain a particular type of Ti plasmid (nopaline, vitopine, and oc-topine/cucumopine Ti plasmids), although a few exceptions occur which may represent rare natural transconju-gants. The Ti plasmid of isolate CG474 did not fit within existing A. vitis Ti plasmid groups.