Genetic Analysis of Three Additional fla Genes in Salmonella typhimuvium

Summary: In Salmonella typhimurium, 27 fla responsible for formation of flagella have been identified and assigned to three regions on the genetic map, termedfla regions I to III. By genetic analysis of 1984 non-flagellate mutants obtained from a phase-1 stable strain of S. typhimurium, SJW 1103, three additional fla genes were identified; one, termed flaW, was assigned to fla region I and the other two, termedflaV andflaX, toflaA region III. By intergeneric complementation tests, the flaW, flaV and flaX genes were shown to be functionally homologous with flaS,flaC and flaP of Escherichia coli, respectively. Electron microscopy showed thatflaW and flaV mutants carried hook-basal body structures.