Recent declines in the health of the honey bee have startled researchers and lay people alike as honey bees are agriculture’s most important pollinator. Honey bees are important pollinators of many major crops and add billions of dollars annually to the US economy through their services. One factor that may influence colony health is the microbial community. Indeed, the honey bee worker digestive tract harbors a characteristic community of bee-specific microbes, and the composition of this community is known to impact honey bee health. However, the honey bee is a superorganism, a colony of eusocial insects with overlapping generations where nestmates cooperate, building a hive, gathering and storing food, and raising brood. In contrast to what is known regarding the honey bee worker gut microbiome, less is known of the microbes associated with developing brood, with food stores, and with the rest of the built hive environment. More recently, the microbe Bombella apis was identified as associated with nectar, with developing larvae, and with honey bee queens. This bacterium is related to flower-associated microbes such as Saccharibacter floricola and other species in the genus Saccharibacter, and initial phylogenetic analyses placed it as sister to these environmental bacteria. Here, we used comparative genomics of multiple honey bee-associated strains and the nectar-associated Saccharibacter to identify genomic changes that may be associated with the ecological transition to honey bee association. We identified several genomic differences in the honey bee-associated strains, including a complete CRISPR/Cas system. Many of the changes we note here are predicted to confer upon Bombella the ability to survive in royal jelly and defend themselves against mobile elements, including phages. Our results are a first step towards identifying potential function of this microbe in the honey bee superorganism.

中文翻译：

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乙酸共生体中蜜蜂关联的基因组特征。


最近蜜蜂健康状况的下降令研究人员和普通民众感到震惊，因为蜜蜂是农业最重要的传粉者。蜜蜂是许多主要农作物的重要授粉媒介，每年通过其服务为美国经济增加数十亿美元。可能影响菌落健康的因素之一是微生物群落。事实上，工蜂消化道中存在着蜜蜂特有的微生物群落，并且众所周知，该群落的组成会影响蜜蜂的健康。然而，蜜蜂是一个超有机体，是一群世代重叠的真社会性昆虫，巢穴成员合作，建造蜂巢，收集和储存食物，并养育幼崽。与对工蜂肠道微生物组的了解相反，我们对与蜂巢发育、食物储存以及其他蜂巢环境相关的微生物知之甚少。最近，蜜蜂Bombella apis微生物被确定与花蜜、发育中的幼虫和蜂王有关。这种细菌与花相关微生物（如弗罗里科糖杆菌（Saccharibacter floricola）和糖杆菌属的其他物种）有关，初步的系统发育分析将其视为这些环境细菌的姐妹。在这里，我们使用多种蜜蜂相关菌株和花蜜相关糖杆菌的比较基因组学来识别可能与蜜蜂关联生态转变相关的基因组变化。我们发现了蜜蜂相关菌株中的几个基因组差异，包括完整的 CRISPR/Cas 系统。 我们在这里注意到的许多变化预计将赋予邦贝拉在蜂王浆中生存并防御包括噬菌体在内的移动元素的能力。我们的结果是确定这种微生物在蜜蜂超有机体中的潜在功能的第一步。