Genetic Analysis of Mutations Affecting pckA Regulation in Rhizobium (Sinorhizobium) meliloti

The enzyme phosphoenolpyruvate carboxykinase (Pck) catalyzes the first step in the gluconeogenic pathway in most organisms. We are examining the genetic regulation of the gene encoding Pck, pckA, in Rhizobium (now Sinorhizobium) meliloti. This bacterium forms N2-fixing root nodules on alfalfa, and the major energy sources supplied to the bacteria within these nodules are C4-dicarboxylic acids such as malate and succinate. R. meliloti cells …