The Genomes of Myxococcus xanthus and Stigmatella aurantiaca

This chapter discusses and compares the genomic sequences of Myxococcus xanthus DK1622 (hereafter referred to as DK1622 or strain DK1622) and Stigmatella aurantiaca DW4/3-1 (hereafter referred to as DW4/3-1 or strain DW4/3-1), two related aerobic, fruiting-body-forming myxobacteria. The structure and complexity of the S. aurantiaca fruiting body are the primary characteristics distinguishing it from M. xanthus DK1622, as well as the production of the signaling pheromone stigmolone, which may be analogous to the M. xanthus DK1622 quorum-sensing A-signal. Having the genome sequence of both organisms will greatly facilitate research into these and other myxobacteria-specific phenotypic traits. The M. xanthus DK1622 genome, initially sequenced to 4.5 coverage by Monsanto, was completed at The Institute for Genomic Research by additional random Sequencing. Both auto- and manual annotation were performed on the closed genome. Unlike most other prokaryotes, the myxobacteria exhibit social behavior and multicellular development. Such complex behavior is correlated with their large genomes. Gliding motility has also been extensively studied in M. xanthus DK1622, which, rather than swimming, hunts by gliding over the soil surface as a coordinated aggregation of thousands of cells, an essential element of its complex lifestyle. Myxobacteria feed by lysing cells of other bacteria and yeasts. Bioactive compounds synthesized and secreted through secondary metabolite biosynthetic gene clusters may aid predation and inhibit competition. The control of development in M. xanthus and S. aurantiaca is likely to be very similar based on the presence of DW4/3-1 orthologs to the genes controlling development in strain DK1622.