Evolutionary history of quorum-sensing systems in bacteria
Evolutionary history of quorum-sensing systems in bacteria
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DOI：
10.1093/molbev/msh097
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发表时间：
2004-05-01
影响因子：
10.7
通讯作者：
Moran, NA
中科院分区：
文献类型：
--
作者：
Lerat, E;Moran, NA
细菌细胞之间通过群体感应QS系统的通讯被用来调节生态和医学上的重要特征，包括对宿主的毒力。QS在细菌中广泛存在；它已在不同的系统发育组中得到实验证明，并且在很大一部分已测序的细菌基因组中发现了与相关基因同源的基因。潜在基因家族(Luxi/R和LuxS)的广泛分布引发了QS基因在细菌谱系之间转移的频率以及同一QS系统中的基因交换伙伴或共同进化的程度的问题。相关基因家族的系统发育分析表明，被标记为Luxi/R诱导子和受体元件的基因由两个家族组成，它们之间几乎没有同源性，一个家族仅限于伽马变形杆菌，另一个家族分布更广泛。在细菌门中，LuxS和两个Luxi/R家族的树与核糖体RNA树显示出广泛的一致性，这表明这些系统在变形杆菌和Firmiccus等类群的进化过程中一直存在。然而，可以推断某些基因的侧向转移(例如，从Firmicuts到LuxS的一些远亲谱系)。总体而言，Luxi/R系统中的诱导/受体元件一起进化，很少交换伴侣，尽管在几个伽马变形杆菌谱系中发生了伴侣的丢失或替换，这是目前数据库中采样最密集的一组。例如，在铜绿假单胞菌中，转移的QS系统已被整合到天然QS系统的途径中。假单胞菌中主要的Luxi/R家族的基因系统发育表明，该属内有复杂的侧向转移、祖先重复和基因丢失的历史。
Communication among bacterial cells through quorum-sensing QS) systems is used to regulate ecologically and medically important traits, including virulence to hosts. QS is widespread in bacteria; it has been demonstrated experimentally in diverse phylogenetic groups, and homologs to the implicated genes have been discovered in a large proportion of sequenced bacterial genomes. The widespread distribution of the underlying gene families (LuxI/R and LuxS) raises the questions of how often QS genes have been transferred among bacterial lineages and the extent to which genes in the same QS system exchange partners or coevolve. Phylogenetic analyses of the relevant gene families show that the genes annotated as LuxI/R inducer and receptor elements comprise two families with virtually no homology between them and with one family restricted to the gamma-Proteobacteria and the other more widely distributed. Within bacterial phyla, trees for the LuxS and the two LuxI/R families show broad agreement with the ribosomal RNA tree, suggesting that these systems have been continually present during the evolution of groups such as the Proteobacteria and the Firmicutes. However, lateral transfer can be inferred for some genes (e.g., from Firmicutes to some distantly related lineages for LuxS). In general, the inducer/receptor elements in the LuxI/R systems have evolved together with little exchange of partners, although loss or replacement of partners has occurred in several lineages of gamma-Proteobacteria, the group for which sampling is most intensive in current databases. For instance, in Pseudomonas aeruginosa, a transferred QS system has been incorporated into the pathway of a native one. Gene phylogenies for the main LuxI/R family in Pseudomonas species imply a complex history of lateral transfer, ancestral duplication, and gene loss within the genus.