Transitions in symbiosis: evidence for environmental acquisition and social transmission within a clade of heritable symbionts.
Transitions in symbiosis: evidence for environmental acquisition and social transmission within a clade of heritable symbionts.
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DOI：
10.1038/s41396-021-00977-z
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发表时间：
2021-10
期刊：
影响因子：
--
通讯作者：
Hurst GDD
中科院分区：
文献类型：
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作者：
Drew GC;Budge GE;Frost CL;Neumann P;Siozios S;Yañez O;Hurst GDD
从自由生活的环境微生物到严格的垂直继承的宿主相关共生体，存在一个动态的连续体。然而，驱动共生生活方式和传播模式转变的力量的知识是缺乏的。砷菌属是一个多样化的细菌共生体分支，包括生殖寄生虫到共同进化的专性互利共生者，其中主要的传播方式是垂直的。我们描述了一个共生属Arsenophonus和西方蜜蜂之间的成员。的共生体共享共同的基因组和预测的代谢特性与男性杀死共生体Arsenophonus nasalgus，但我们提出了多条线的证据表明，蜜蜂Arsenophonus偏离遗传模型的传输。现场采样揭示了共生体流行的空间和季节动态，并观察到现场菌落和实验室个人的快速感染损失事件。荧光原位杂交显示，砷螨定位于肠道，检测是罕见的早期蜜蜂生命阶段的屏幕。我们直接展示了在不同社会条件下蜜蜂之间的砷螨水平传播。我们的结论是，蜜蜂获得Arsenophonus通过环境暴露和社会接触的结合。这些发现揭示了Arsenophonus分支轨迹中的一个关键环节，从自由生活的祖先生活到专性互利共生，并为研究共生生活方式的转变提供了基础。
A dynamic continuum exists from free-living environmental microbes to strict host-associated symbionts that are vertically inherited. However, knowledge of the forces that drive transitions in symbiotic lifestyle and transmission mode is lacking. Arsenophonus is a diverse clade of bacterial symbionts, comprising reproductive parasites to coevolving obligate mutualists, in which the predominant mode of transmission is vertical. We describe a symbiosis between a member of the genus Arsenophonus and the Western honey bee. The symbiont shares common genomic and predicted metabolic properties with the male-killing symbiont Arsenophonus nasoniae, however we present multiple lines of evidence that the bee Arsenophonus deviates from a heritable model of transmission. Field sampling uncovered spatial and seasonal dynamics in symbiont prevalence, and rapid infection loss events were observed in field colonies and laboratory individuals. Fluorescent in situ hybridisation showed Arsenophonus localised in the gut, and detection was rare in screens of early honey bee life stages. We directly show horizontal transmission of Arsenophonus between bees under varying social conditions. We conclude that honey bees acquire Arsenophonus through a combination of environmental exposure and social contacts. These findings uncover a key link in the Arsenophonus clades trajectory from free-living ancestral life to obligate mutualism, and provide a foundation for studying transitions in symbiotic lifestyle.