Griffin Joanne S, Gerth Michael, Hurst Gregory D D
Department of Evolution, Ecology and Behaviour, University of Liverpool, Liverpool, UK.
German Centre for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig, Leipzig, Germany.
Microbiology (Reading). 2022 Dec;168(12). doi: 10.1099/mic.0.001281.
Heritable symbionts represent important components of the biology, ecology and evolution of their arthropod hosts. Particular microbial taxa have become common across arthropods as a consequence of their ability to establish in new host species. For a host shift to occur, the symbiont must be exposed to a novel host and then be compatible: it must not cause excess pathology, must have good vertical transmission and must possess a drive phenotype that enables spread. Here we investigate the lability of compatibility to symbiosis with . We used transinfection to establish the protective symbiont from in two closely related novel hosts, and . The had contrasting compatibility in the two species, exhibiting pathology and low vertical transmission but delivering protection from wasp attack in but being asymptomatic and transmitted with high efficiency but with lower protection in . Further work indicated that pathological interactions occurred in two other members of the melanogaster species group, such that was unusual in being able to carry the symbiont without damage. The differing compatibility of the symbiont with these closely related host species emphasizes the rapidity with which host-symbiont compatibility evolves, despite compatibility itself not being subject to direct selection. Further, the requirement to fit three independent components of compatibility (pathology, transmission, protection) is probably to be a major feature limiting the rate of host shifts that will likely impact on the utility of in pest and vector control. Moving forward, the variation between sibling species pairs provides an opportunity to identify the mechanisms behind variable compatibility, which will drive hypotheses as to the evolutionary drivers of compatibility variation.
可遗传共生菌是其节肢动物宿主生物学、生态学和进化的重要组成部分。由于某些特定微生物类群能够在新宿主物种中定殖，它们在节肢动物中变得很常见。要发生宿主转移，共生菌必须接触到新宿主并与之相容：它不能引起过多病变，必须具有良好的垂直传播能力，并且必须具有能够实现传播的驱动表型。在这里，我们研究了与……共生的相容性的不稳定性。我们通过转染在两个密切相关的新宿主……和……中建立了来自……的保护性共生菌。该共生菌在这两个物种中的相容性形成对比，在……中表现出病变和低垂直传播率，但能提供免受黄蜂攻击的保护，而在……中无症状且高效传播，但保护作用较低。进一步的研究表明，在黑腹果蝇物种组的另外两个成员中也发生了病理相互作用，因此……能够携带共生菌而不造成损害是不寻常的。共生菌与这些密切相关宿主物种的不同相容性强调了宿主 - 共生菌相容性进化的快速性，尽管相容性本身不受直接选择的影响。此外，要满足相容性的三个独立组成部分（病变、传播、保护）的要求，可能是限制宿主转移速率的一个主要因素，这可能会影响……在害虫和病媒控制中的效用。展望未来，姐妹物种对之间的差异提供了一个机会来确定可变相容性背后的机制，这将推动关于相容性变异进化驱动因素的假设。
