Strategies of genomic integration within insect-bacterial mutualisms.
Strategies of genomic integration within insect-bacterial mutualisms.
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DOI：
10.1086/bblv223n1p112
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发表时间：
2012-08
期刊：
影响因子：
--
通讯作者：
Wernegreen JJ
中科院分区：
文献类型：
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作者：
Wernegreen JJ
昆虫是最多样化的大型生物群体，已知有90万种，是共生关系进化的丰富游乐场。这个庞大的动物群的共生体包括一系列的微生物伙伴。昆虫倾向于与细胞内细菌建立关系，其中包括生物界已知的最亲密、高度整合的互惠关系。近年来，基因组研究的爆炸式增长为这些昆虫-细菌伙伴关系的分子、功能和进化后果提供了新的见解。在这篇综述中，我重点介绍了细菌内共生体的基因组序列和选择的昆虫宿主的一些见解。值得注意的是，兼性细菌与专性细菌的比较揭示了不同的基因组特征，代表了基因组减少的共同轨迹上的不同阶段。与雪松蚜虫相关的细菌提供了从兼性共生到专性共生过渡的快照，说明了共生光谱中这一关键步骤的基因组基础。此外，稳定的双细菌共生体的基因组反映了惊人的代谢整合的独立实例。在这些系统中，关键营养物质的合成，也许还有基本的细胞过程，需要共同居住的细菌和它们的昆虫宿主之间的合作。这些发现为细菌-动物共生的基因组探索的新时代提供了一个起点。未来的研究有望揭示在广泛的生态和系统发育范围内的共生策略，阐明沿相互作用类型谱的关键转变，并推动新的实验方法来解剖亲密宿主-共生体关联的机制基础。
Insects, the most diverse group of macroorganisms with 900,000 known species, have been a rich playground for the evolution of symbiotic associations. Symbionts of this enormous animal group include a range of microbial partners. Insects are prone to establishing relationships with intracellular bacteria, which include the most intimate, highly integrated mutualisms known in the biological world. In recent years, an explosion of genomic studies has offered new insights into the molecular, functional, and evolutionary consequences of these insect-bacterial partnerships. In this review, I highlight some insights from genome sequences of bacterial endosymbionts and select insect hosts. Notably, comparisons of facultative versus obligate bacterial mutualists have revealed distinct genome features representing different stages along a shared trajectory of genome reduction. Bacteria associated with the cedar aphid offer a snapshot of a transition from facultative to obligate mutualism, illustrating the genomic basis of this key step along the symbiotic spectrum. In addition, genomes of stable, dual bacterial symbionts reflect independent instances of astonishing metabolic integration. In these systems, synthesis of key nutrients, and perhaps basic cellular processes, require collaboration among co-residing bacteria and their insect host. These findings provide a launching point for a new era of genomic explorations of bacterial-animal symbioses. Future studies promise to reveal symbiotic strategies across a broad ecological and phylogenetic range, to clarify key transitions along a spectrum of interaction types, and to fuel new experimental approaches to dissect the mechanistic basis of intimate host-symbiont associations.