GENETICS OF GLIDING MOTILITY IN MYXOCOCCUS-XANTHUS (MYXOBACTERALES) - 2 GENE SYSTEMS CONTROL MOVEMENT

A large number of motility mutants of the gliding bacterium Myxococcus xanthus have been isolated and analyzed by transduction. Almost all nonmotile mutants are found to be double mutants. This is explained by the existence of two parallel and almost independent multi-gene systems controlling motility, in which case at least one mutation in each system would be required eliminate motility. Only one locus, called mgl, has been found to be shared by both systems. Wild type cells move singly and in groups. Single cells move if they carry a complete gene system A, the genes of which are described in the preceding paper. Groups of cells can move if they carry a complete gene system S, but single A-S+ cells do not move. Linkage analysis reveals at least 9 different loci in system S. One class of S- mutants, those mutated in the locus tgl, are conditional mutants which, after contact with tgl+ cells, become temporarily motile as cell groups. Most system A mutations have little effect on fruiting but many system S mutations block it, suggesting that system S plays a role in the fruiting process. © 1979 Springer-Verlag.