ABSTRACT
The capacity to cause plant disease has evolved in a relatively small number of bacterial species which are phenotypically and genetically diverse. Below the level of the species the strains that make up these species also vary in genotype and phenotype. Traditionally phenotypic techniques such as substrate utilisation profiles and total fatty acid composition have been employed to characterise plant-pathogenic bacteria. Recently more reliable DNA-based methods have been applied which provide a more complete understanding of genetic and evolutionary relationships of bacteria.
