Insect-symbiont gene expression in the midgut bacteriocytes of a blood-sucking parasite
Insect-symbiont gene expression in the midgut bacteriocytes of a blood-sucking parasite
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吸血寄生虫中肠细菌细胞中昆虫共生基因的表达
DOI：
10.1101/572495
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Filip H
中科院分区：
文献类型：
--
作者：
Filip H
动物与各种各样的有益和有害微生物相互作用。在昆虫中，这些共生体在许多情况下允许以营养不平衡的饮食为食。然而，目前还不清楚专性共生体是如何在细胞水平上维持数亿年的。驱动宿主-共生体相互作用的确切机制仅为少数模式物种所理解，并且关于具有细胞内细菌的血液喂养宿主的数据特别稀少。在这里，我们分析了专性吸血寄生虫的羊，虱蝇Melophagus ovinus，其专性内共生体，Arsenophonus melophagi之间的相互作用。我们为昆虫宿主组装了参考转录组，并使用具有五个生物重复的双重RNA-Seq来比较专门用于容纳共生细菌（细菌细胞）的中肠细胞与肠道其余部分（前肠-后肠）中的表达。我们发现了强有力的证据表明，锌在系统中的重要性可能是由共生体使用锌依赖性蛋白酶时，获取氨基酸，并为不同的免疫机制控制共生体比密切相关的采采蝇。我们的研究结果表明，这种吸血昆虫和它的共生体之间的细胞和营养的相互作用是不那么亲密比以前发现的大多数植物汁液吸吮昆虫。这一发现可能与在吸血节肢动物共生体中观察到的几个特征相关，特别是它们的中肠细胞内定位、胞质内存在、不太严重的基因组减少以及由频繁的进化损失和替换引起的相对较新的关联。
Animals interact with a diverse array of both beneficial and detrimental microorganisms. In insects, these symbioses in many cases allow feeding on nutritionally unbalanced diets. It is, however, still not clear how are obligate symbioses maintained at the cellular level for up to several hundred million years. Exact mechanisms driving host–symbiont interactions are only understood for a handful of model species and data on blood-feeding hosts with intracellular bacteria are particularly scarce. Here, we analyzed interactions between an obligately blood-sucking parasite of sheep, the louse flyMelophagus ovinus, and its obligate endosymbiont,Arsenophonus melophagi. We assembled a reference transcriptome for the insect host and used dual RNA-Seq with five biological replicates to compare expression in the midgut cells specialized for housing symbiotic bacteria (bacteriocytes) to the rest of the gut (foregut–hindgut). We found strong evidence for the importance of zinc in the system likely caused by symbionts using zinc-dependent proteases when acquiring amino acids, and for different immunity mechanisms controlling the symbionts than in closely related tsetse flies. Our results show that cellular and nutritional interactions between this blood-sucking insect and its symbionts are less intimate than what was previously found in most plant-sap sucking insects. This finding is likely interconnected to several features observed in symbionts in blood-sucking arthropods, particularly their midgut intracellular localization, intracytoplasmic presence, less severe genome reduction, and relatively recent associations caused by frequent evolutionary losses and replacements.