Genome evolution and the emergence of fruiting body development in Myxococcus xanthus

• Published in: PloS one 2007-12, Vol.2 (12), p.e1329-e1329
• Main Authors: Goldman, Barry, Bhat, Swapna, Shimkets, Lawrence J
• Format: Article
• Language: English
• Subjects: Aerobic respiration; Algorithms; Anaeromyxobacter; Bacteria; Bacterial proteins; Bias; Biodiversity; Bioinformatics; Biological Evolution; Codon bias; Codons; Cytochrome; Desulfovibrio; Developmental Biology/Microbial Growth and Development; Disease transmission; Divergence; Electron transport; Environmental degradation; Evolution; Evolutionary Biology/Developmental Evolution; Evolutionary Biology/Microbial Evolution and Genomics; Fruit bodies; Fruits; Gene pool; Gene transfer; Gene Transfer, Horizontal; Genes; Genes, Bacterial; Genes, Essential; Genetics and Genomics/Gene Discovery; Genetics and Genomics/Microbial Evolution and Genomics; Genome, Bacterial; Genomes; Genomics; Geobacter; Handbooks; Innovations; Integrated software; Lawsonia; Metabolism; Microbiology/Microbial Evolution and Genomics; Microbiology/Microbial Growth and Development; Microbiology/Microbial Physiology and Metabolism; Motility; Myxococcus xanthus; Myxococcus xanthus - genetics; Myxococcus xanthus - growth & development; Myxococcus xanthus - metabolism; Organisms; Oxidase; Oxidases; Oxygen - metabolism; Phylogenetics; Phylogeny; Prokaryotes; Proteobacteria; rRNA 16S; Sensory transduction; Speciation; Species diversity; Succinate dehydrogenase; Transduction
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0001329

Lateral gene transfer (LGT) is thought to promote speciation in bacteria, though well-defined examples have not been put forward. We examined the evolutionary history of the genes essential for a trait that defines a phylogenetic order, namely fruiting body development of the Myxococcales. Seventy-eight genes that are essential for Myxococcus xanthus development were examined for LGT. About 73% of the genes exhibit a phylogeny similar to that of the 16S rDNA gene and a codon bias consistent with other M. xanthus genes suggesting vertical transmission. About 22% have an altered codon bias and/or phylogeny suggestive of LGT. The remaining 5% are unique. Genes encoding signal production and sensory transduction were more likely to be transmitted vertically with clear examples of duplication and divergence into multigene families. Genes encoding metabolic enzymes were frequently acquired by LGT. Myxobacteria exhibit aerobic respiration unlike most of the delta Proteobacteria. M. xanthus contains a unique electron transport pathway shaped by LGT of genes for succinate dehydrogenase and three cytochrome oxidase complexes. Fruiting body development depends on genes acquired by LGT, particularly those involved in polysaccharide production. We suggest that aerobic growth fostered innovation necessary for development by allowing myxobacteria access to a different gene pool from anaerobic members of the delta Proteobacteria. Habitat destruction and loss of species diversity could restrict the evolution of new bacterial groups by limiting the size of the prospective gene pool.