ABSTRACT
Mutation in bacterial plant pathogens are known to occur for various characters, such as mutation for pathogenicity, mutation for pigmentation, mutation for antibiotic resistance, mutation for morphological characters, physiological characters or biochemical characters, and so on. Due to environmental conditions or growth conditions, a few cells in the bacterial population mutate for a particular genetic character. An abrupt change in the genetic character is known as a mutation and occurs in one-in-a-million populations. Genetic and biochemical investigations in bacteriology are often initiated by the isolation of mutants. In order to detect mutants of a particular organism, one must know the normal or wild characteristics so as to recognize an altered phenotype. The colonies of test bacterium that appear in the area of high streptomycin concentration will be streptomycin-resistant mutants. Select and mark an isolated colony of test bacterium in the high streptomycin concentration area.
