Simple Cultural Tests for Identification of Agrobacterium Biovars

In Bergey’s Manual of Systematic Bacteriology (1 ), the genus Agrobacterium is divided into four species (A. radiobacter, A. rhizogenes, A. rubi , and A. tumefaciens ) based on phytopathogenic characters. With the exception of A. rubi , each species is subdivided into three biovars based on physiological and biochemical tests (1 ). In the past three decades, it has been shown that the true taxonomic structure of the genus is not based on pathogenicity but rather on chromosomal groups that are represented by the biovars (1 –4 ). As a result, there have been several proposed revisions of the species classification in Agrobacterium . However, to avoid confusion in this chapter, we refer to the strains by their biovar designation.