Cover photograph (Copyright © 2006, American Society for Microbiology. All Rights Reserved.): Stigmatella aurantiaca fruiting body formation. Integration at the Stigmatella aurantiaca phage attachment site, attB, affects expression of the tRNA operon, trnVD, resulting in a block in development. The mutation was complemented by supplying a wild-type copy of the trnVD locus in trans. The photograph shows the merodiploid, which is capable of generating fruiting bodies that resemble those produced by the wild type. (See related article on page 1701.)