EVIDENCE FOR PHYLOGENETIC CONGRUENCE AMONG SULFUR-OXIDIZING CHEMOAUTOTROPHIC BACTERIAL ENDOSYMBIONTS AND THEIR BIVALVE HOSTS
EVIDENCE FOR PHYLOGENETIC CONGRUENCE AMONG SULFUR-OXIDIZING CHEMOAUTOTROPHIC BACTERIAL ENDOSYMBIONTS AND THEIR BIVALVE HOSTS
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DOI：
10.1007/bf00178852
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发表时间：
1994-05-01
影响因子：
3.9
通讯作者：
CAVANAUGH, CM
中科院分区：
文献类型：
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作者：
DISTEL, DL;FELBECK, H;CAVANAUGH, CM
硫氧化化自养（硫自养）细菌现在被认为是在各种海洋环境中发现的系统发育多样的双壳类宿主中的内共生体。然而，这些共生的进化起源仍然不清楚。比较16S rRNA序列分析用于研究硫自养内共生菌的起源是单系还是多系，并评估这些共生体之间的系统发育关系是否反映了其宿主之间的系统发育关系。将新检测的三科（Vesicomyidae, Lucinidae, Solemyidae）九种双壳类内共生菌的16S rRNA基因序列与先前发表的硫自养共生菌和自由生活细菌的16S rRNA序列进行比较。用距离法和简约法来推断这些细菌之间的系统发育关系。所有新研究的共生体都属于变形菌门的伽马分支，在包含以前研究过的共生硫自养菌的集群中。这些共生体最接近的自由生活的亲戚是硫微螺旋体属的细菌。双壳超科Lucinacea和Vesicomyidae的共生体各自形成了不同的单系谱系，这一点得到了bootstrap分析的有力支持，表明从形态学和化石证据推断的宿主系统发生与通过分子序列分析推断的各自共生体系统发生是一致的。寄主和共生体系统发育的一致性表明寄主和共生体谱系的共同进化历史，并表明这些共生体有一个古老的起源。
Sulfur-oxidizing chemoautotrophic (thioautotrophic) bacteria are now known to occur as endosymbionts in phylogenetically diverse bivalve hosts found in a wide variety of marine environments. The evolutionary origins of these symbioses, however, have remained obscure. Comparative 16S rRNA sequence analysis was used to investigate whether thioautotrophic endosymbionts are monophyletic or polyphyletic in origin and to assess whether phylogenetic relationships inferred among these symbionts reflect those inferred among their hosts. 16S rRNA gene sequences determined for endosymbionts from nine newly examined bivalve species from three families (Vesicomyidae, Lucinidae, and Solemyidae) were compared with previously published 16S rRNA sequences of thioautotrophic symbionts and free-living bacteria. Distance and parsimony methods were used to infer phylogenetic relationships among these bacteria. All newly examined symbionts fall within the gamma subdivision of the Proteobacteria, in clusters containing previously examined symbiotic thioautotrophs. The closest free-living relatives of these symbionts are bacteria of the genus Thiomicrospira. Symbionts of the bivalve superfamily Lucinacea and the family Vesicomyidae each form distinct monophyletic lineages which are strongly supported by bootstrap analysis, demonstrating that host phylogenies inferred from morphological and fossil evidence are congruent with phylogenies inferred for their respective symbionts by molecular sequence analysis. The observed congruence between host and symbiont phylogenies indicates shared evolutionary history of hosts and symbiont lineages and suggests an ancient origin for these symbioses.