Conjugational Gene Transfer in Xanthobacter autotrophicus GZ29

A low-frequency recombination system, requiring direct cell contact and permitting transfer of large chromosomal segments, has been found in the nitrogen-fixing hydrogen bacterium Xanthobacter autotrophicus GZ29. All partners used in plate mating experiments functioned as donors as well as recipients. Two groups of closely linked markers were found by recombination analysis. The mutations of a number of autotrophic-negative mutants were placed in one or other of these two linkage groups.