Distinction of biovar 2 strains of Agrobacterium from other chromosomal groups by differential acid production

Biovar (bv) 2 strains of Agrobacterium produced more acid from glucose than strains from the other two biovars This property caused the development of a clear zone around bv-2 colonies growing on potato glucose agar supplemented with 0.8% calcium carbonate. This simple cultural test produced results after 2 d at 28°C, and distinguished all 22 bv-2 strains tested from strains of other chromosomal groups of Agrobacterium ; none of the 42 bv-1 and 16 bv-3 strains tested produced a clear zone around their colonies.