Niche partitioning facilitates coexistence of closely related honey bee gut bacteria.
Niche partitioning facilitates coexistence of closely related honey bee gut bacteria.
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DOI：
10.7554/elife.68583
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发表时间：
2021-07-19
期刊：
影响因子：
7.7
通讯作者：
Engel P
中科院分区：
文献类型：
--
作者：
Brochet S;Quinn A;Mars RAT;Neuschwander N;Sauer U;Engel P
肠道细菌共存的生态过程尚不清楚。在这里，我们理清了宿主和饮食对定植于蜜蜂肠道的四种密切相关的乳酸菌物种共存的影响。我们通过知生蜜蜂和在花粉（蜜蜂饮食）或单糖存在的液体培养物中连续传代这四个物种。尽管这四个物种存在负相互作用，但它们在体内和体外都能稳定共存。然而，共存只有在花粉存在的情况下才有可能，而在单糖中则不可能，与环境无关。利用宏转录组学和代谢组学，我们发现这四个物种利用不同的花粉来源的碳水化合物底物，表明资源分配是共存的基础。我们的结果表明，尽管存在长期的宿主关联，但与体内实验相结合时，肠道细菌相互作用可以在体外重现，从而提供有关细菌共存的见解。微生物几乎遍布地球上的每一个环境，从海洋和土壤到动物的内表面和外表面，例如肠道或皮肤。它们形成的群落通常由多种细菌组成，通常包含密切相关的物种——这是群落成功的关键因素。但密切相关的细菌可以争夺相同的资源，因此尚不清楚它们如何能够在不相互竞争的情况下彼此共存。虽然饮食被认为在使密切相关的细菌种类在动物肠道中共存方面发挥着关键作用，但由于在实验室中复制这些系统存在困难，因此缺乏实验证据。研究微生物群落的一种策略是使用蜜蜂。蜜蜂的主要饮食来源是花粉，花粉也可以在实验室中用于培养蜜蜂肠道中发现的多种细菌。此外，科学家还可以培育出肠道中缺乏微生物群落的蜜蜂，让它们添加特定类型的细菌来研究其影响。布罗切特等人。使用这种方法与西方蜜蜂一起评估饮食是否能够使密切相关的细菌在肠道中彼此共存。首先，他们将缺乏肠道微生物的蜜蜂与四种密切相关的乳酸菌属细菌单独或一起定植，并给蜜蜂喂糖水或糖水和花粉。五天后，对肠道细菌进行了分析。这表明，以糖水喂养的蜜蜂肠道中只存在一种占优势的乳杆菌，而以额外花粉喂养的蜜蜂则含有所有四种乳杆菌。对这四种细菌的进一步分析表明，当它们在花粉上生长时，每种细菌都会激活不同的基因，从而使不同的物种能够从分解的花粉中消耗特定的营养物质。这些发现表明，密切相关的细菌可以通过共享宿主饮食中提供的不同营养物质在肠道中共存。因此，蜜蜂和其他动物饮食摄入量的差异可能会影响肠道细菌的多样性，并可能影响动物的健康。
Ecological processes underlying bacterial coexistence in the gut are not well understood. Here, we disentangled the effect of the host and the diet on the coexistence of four closely related Lactobacillus species colonizing the honey bee gut. We serially passaged the four species through gnotobiotic bees and in liquid cultures in the presence of either pollen (bee diet) or simple sugars. Although the four species engaged in negative interactions, they were able to stably coexist, both in vivo and in vitro. However, coexistence was only possible in the presence of pollen, and not in simple sugars, independent of the environment. Using metatranscriptomics and metabolomics, we found that the four species utilize different pollen-derived carbohydrate substrates indicating resource partitioning as the basis of coexistence. Our results show that despite longstanding host association, gut bacterial interactions can be recapitulated in vitro providing insights about bacterial coexistence when combined with in vivo experiments. Microbes colonize nearly every environment on Earth, from the ocean and soil to the inner and outer surfaces of animals, such as the gut or skin. They form communities that are usually made up of a diverse range of bacteria, often containing closely related species – a key factor for a successful community. But closely related bacteria can battle for the same resources, so it is unclear how they manage to live alongside each other without competing against one another. While diet is thought to play a key role in enabling closely related bacterial species to co-exist in the gut of an animal, experimental evidence is lacking, due to the difficulty in replicating these systems in the laboratory. One strategy for investigating microbial communities is using honeybees. A major dietary source for honeybees is pollen, which can also be applied in the laboratory to grow diverse types of bacteria found in the honeybee gut. In addition, scientists can generate bees that lack microbial communities in the gut, allowing them to add specific types of bacteria to study their impact. Brochet et al. used this approach with Western honeybees to assess whether diet enables closely related bacteria to live alongside one another in the gut. First, they colonized bees that lacked gut microbes with four closely related bacteria of the genus Lactobacillus, alone or together, and fed the bees either sugar water or sugar water and pollen. After five days, the gut bacteria were analysed. This revealed that bees fed on sugar water only had one dominant Lactobacillus species present in their gut, while bees fed with additional pollen harboured all four Lactobacillus species. Further analysis of these four bacterial species revealed that each of them activates distinct genes when grown on pollen, allowing the different species to consume specific nutrients from broken down pollen. These findings show that closely related bacteria can coexist in the gut by sharing the different nutrients provided in the diet of the host. Consequently, differences in dietary intake in honeybees and other animals may affect the diversity of gut bacteria, and potentially the health of an animal.