In nature, bacteria form biofilms by producing exopolymeric matrix that encases its entire community. While it is widely known that biofilm matrix can prevent bacterivore predation and contain virulence factors for killing predators, it is unclear if they can alter predator motility. Here, we report a novel “quagmire” phenotype, where Pseudomonas aeruginosa biofilms could retard the motility of bacterivorous nematode Caenorhabditis elegans via the production of a specific exopolysaccharide, Psl. Psl could reduce the roaming ability of C. elegans by impeding the slithering velocity of C. elegans. Furthermore, the presence of Psl in biofilms could entrap C. elegans within the matrix, with dire consequences to the nematode. After being trapped in biofilms, C. elegans could neither escape effectively from aversive stimuli (noxious blue light), nor leave easily to graze on susceptible biofilm areas. Hence, this reduced the ability of C. elegans to roam and predate on biofilms. Taken together, our work reveals a new function of motility interference by specific biofilm matrix components, and emphasizes its importance in predator–prey interactions.

在自然界中，细菌通过产生包围其整个群落的外聚基质来形成生物膜。虽然众所周知，生物膜基质可以防止食菌动物捕食并含有杀死捕食者的毒力因子，但尚不清楚它们是否可以改变捕食者的运动性。在这里，我们报告了一种新的“泥潭”表型，其中铜绿假单胞菌生物膜可以通过产生特定的胞外多糖 Psl来阻碍食细菌线虫秀丽隐杆线虫的运动。PSL可以减少漫游能力线虫通过阻碍的滑行速度线虫。此外，生物膜中 Psl 的存在可以诱捕线虫在基质内，对线虫造成可怕的后果。被困在生物膜中后，秀丽隐杆线虫既不能有效地摆脱厌恶刺激（有害蓝光），也不能轻易离开，在易感生物膜区域吃草。因此，这降低了秀丽隐杆线虫在生物膜上漫游和捕食的能力。总之，我们的工作揭示了特定生物膜基质成分对运动性干扰的新功能，并强调了其在捕食者-猎物相互作用中的重要性。