Bacterial virulence factors facilitate host colonization and set the stage for the evolution of parasitic and mutualistic interactions. The Sodalis-allied clade of bacteria exhibit striking diversity in the range of both plant and animal feeding insects they inhabit, suggesting the appropriation of universal molecular mechanisms that facilitate establishment. Here, we report on the infection of the tsetse fly by free-living Sodalis praecaptivus, a close relative of many Sodalis-allied symbionts. Key genes involved in quorum sensing, including the homoserine lactone synthase (ypeI) and response regulators (yenR and ypeR) are integral for the benign colonization of S. praecaptivus. Mutants lacking ypeI, yenR and ypeR compromised tsetse survival as a consequence of their inability to repress virulence. Genes under quorum sensing, including homologs of the binary insecticidal toxin PirAB and a putative symbiosis-promoting factor CpmAJ, demonstrated negative and positive impacts, respectively, on tsetse survival. Taken together with results obtained from experiments involving weevils, this work shows that quorum sensing virulence suppression plays an integral role in facilitating the establishment of Sodalis-allied symbionts in diverse insect hosts. This knowledge contributes to the understanding of the early evolutionary steps involved in the formation of insect-bacterial symbiosis. Further, despite having no established history of interaction with tsetse, S. praecaptivus can infect reproductive tissues, enabling vertical transmission through adenotrophic viviparity within a single host generation. This creates an option for the use of S. praecaptivus in the biocontrol of insect disease vectors via paratransgenesis.

细菌毒力因子促进宿主定植，并为寄生和互利相互作用的进化奠定了基础。 Sodalis -allied细菌进化枝在它们所栖息的植物和动物饲养昆虫的范围内表现出惊人的多样性，这表明利用了促进建立的通用分子机制。在这里，我们报告了自由生活的Sodalis praecaptivus对采采蝇的感染，它是许多Sodalis相关共生体的近亲。参与群体感应的关键基因，包括高丝氨酸内酯合酶 ( ypeI ) 和反应调节因子（ yenR和ypeR ），是链球菌良性定植的组成部分。预俘虏。缺乏ypeI 、 yenR和ypeR的突变体由于无法抑制毒力而损害了采采蝇的存活。群体感应下的基因，包括二元杀虫毒素 PirAB 的同源物和假定的共生促进因子 CpmAJ，分别对采采蝇的生存产生了负面和积极的影响。结合涉及象鼻虫的实验获得的结果，这项工作表明群体感应毒力抑制在促进Sodalis相关共生体在不同昆虫宿主中的建立中发挥着不可或缺的作用。这些知识有助于理解昆虫-细菌共生形成的早期进化步骤。此外，尽管没有与采采蝇相互作用的既定历史， S . praecaptivus可以感染生殖组织，在单代宿主内通过腺营养胎生实现垂直传播。这创建了使用S的选项。 praecaptivus通过副转基因对昆虫疾病媒介进行生物防治。