AGROBACTERIUM-VITIS SP-NOV FOR STRAINS OF AGROBACTERIUM BIOVAR-3 FROM GRAPEVINES

Agrobacterium isolates from grapevines that were previously characterized as biovar 3 strains were compared with the type strains of the four previously described species of the genus Agrobacterium, Agrobacterium tumefaciens, Agrobacterium radiobacter, Agrobacterium rhizogenes, and Agrobacterium rubi. Ten grapevine isolates were distinguished from other Agrobacterium species phenotypically by a number of biochemical tests and by their reaction with a monoclonal antibody raised to biovar 3. Levels of DNA binding between the type strains of previously described species and three grapevine isolates were estimated by optical measurement of initial DNA renaturation rates. The levels of DNA binding between grapevine isolates were 78 to 92%, and the levels of DNA binding with other type strains ranged from 7 to 47%. Our results indicate that the grapevine isolates are distinct from the type strains of the four previously described Agrobacterium species. A new species, Agrobacterium vitis, is proposed; the type strain is strain NCPPB 3554.