Expression‐based identification of genetic determinants of the bacterial symbiosis ‘ Chlorochromatium aggregatum ’

作者：Roland Wenter, Katharina Hütz, Dörte Dibbern, Tao Li, Veronika Reisinger, Matthias Plöscher, Lutz A. Eichacker, B. Eddie, Thomas E. Hanson, Donald A. Bryant, Jörg Overmann · 发表于：Environmental Microbiology · 年份：2010 · DOI：10.1111/j.1462-2920.2010.02206.x · 被引用次数：14 · 研究领域：Microbial Community Ecology and Physiology、Genomics and Phylogenetic Studies、Protist diversity and phylogeny

The phototrophic consortium 'Chlorochromatium aggregatum' is a highly structured association of green sulfur bacterial epibionts surrounding a central, motile bacterium and is the most specific symbiosis currently known between two phylogenetically distinct bacterial species. Genes and gene products potentially involved in the symbiotic interaction were identified on the genomic, transcriptomic and proteomic level. As compared with the 11 available genomes of free-living relatives, only 186 open reading frames were found to be unique to the epibiont genome. 2-D differential gel electrophoresis (2-D DIGE) of the soluble proteomes recovered 1612 protein spots of which 54 were detected exclusively in consortia but not in pure epibiont cultures. Using mass spectrometry analyses, the 13 most intense of the 54 spots could be attributed to the epibiont. Analyses of the membrane proteins of consortia, of consortia treated with cross-linkers and of pure cultures indicated that a branched chain amino acid ABC-transporter binding protein is only expressed in the symbiotic state of the epibiont. Furthermore, analyses of chlorosomes revealed that an uncharacterized 11 kDa epibiont protein is only expressed during symbiosis. This protein may be involved in the intracellular sorting of chlorosomes. Application of a novel prokaryotic cDNA suppression subtractive hybridization technique led to identification of 14 differentially regulated genes, and comparison of the transcriptomes of symbiot...