Sofie De Meyer

The aim of this chapter is to provide a selection of specialised genetic techniques which are widely used to interrogate gene functions in root nodule bacteria (RNB). The reader is referred to reviews of the applicability of these techniques to understand biological processes occurring in RNB (i.e. Long 1989; Stanley and Cervantes 1991). The techniques presented here cover the ability to randomly mutate genes, select mutants of interest based on their phenotype and identify the gene affected, verify that the gene mutation caused the observed phenotypic defect, examine expression of a target gene, perform genome structural and func¬tional studies and conduct comparative analyses with other RNB.