Data from: Selection experiments reveal trade-offs between swimming and twitching motilities in Pseudomonas aeruginosa

Bacteria possess a range of mechanisms to move in different environments, and these mechanisms have important direct and correlated impacts on the virulence of opportunistic pathogens. Bacteria use two surface organelles to facilitate motility: a single polar flagellum, and type IV pili, enabling swimming in aqueous habitats and twitching along hard surfaces, respectively. Here, we address whether there are trade-offs between these motility mechanisms, and hence whether different environments could select for altered motility. We experimentally evolved initially isogenic Pseudomonas aeruginosa under conditions which favoured the different types of motility, and found evidence for a trade-off mediated by antagonistic pleiotropy between swimming and twitching. Moreover, changes in motility resulted in correlated changes in other behaviours, including biofilm formation and growth within an insect host. This suggests environmental origins of a particular motile opportunistic pathogen could predictably influence motility and virulence.

细菌拥有多种可在不同环境中移动的机制，这些机制对机会致病菌的毒力具有重要的直接影响与关联效应。细菌借助两种表面细胞器实现运动：单极鞭毛（single polar flagellum）与IV型菌毛（type IV pili），二者分别可使细菌在水生生境中完成游泳运动，以及沿硬质表面进行抽搐运动。本研究旨在探究这两种运动机制之间是否存在权衡关系，以及不同环境是否会对运动方式的改变产生选择压力。我们在偏向不同运动类型的实验条件下，对初始为同基因的铜绿假单胞菌（Pseudomonas aeruginosa）进行了实验进化，结果发现游泳运动与抽搐运动之间存在由拮抗多效性（antagonistic pleiotropy）介导的权衡关系。此外，运动方式的改变还会引发其他行为的关联变化，包括生物膜（biofilm）形成以及在昆虫宿主体内的增殖。这表明，某一运动型机会致病菌的环境起源，可对其运动能力与毒力产生可预测的影响。