Cystic fibrosis (CF) is a genetic disease that affects mucin-producing body organs such as the lungs. Characteristic of CF is the production of thick, viscous mucus, containing the glycoprotein mucin, that can lead to progressive airway obstruction. Recently, we demonstrated that the presence of mucin induced a rapid surface adaptation in motile bacteria termed surfing motility, which data presented here indicates is very different from swarming motility. Pseudomonas aeruginosa, the main colonizing pathogen in CF, employs several stress coping mechanisms to survive the highly viscous environment of the CF lung. We used motility-based assays and RNA-Seq to study the stringent stress response in the hypervirulent CF isolate LESB58 (Liverpool Epidemic Strain). Motility experiments revealed that an LESB58 stringent response mutant (ΔrelAΔspoT) was unable to surf. Transcriptional profiling of ΔrelAΔspoT mutant cells from surfing agar plates, when compared to wild-type cells from the surfing edge, revealed 2,584 dysregulated genes. Gene Ontology and KEGG enrichment analysis revealed effects of the stringent response on amino acid, nucleic acid and fatty acid metabolism, TCA cycle and glycolysis, type VI secretion, as well as chemotaxis, cell communication, iron transport, nitrogen metabolic processes and cyclic-di-GMP signalling. Screening of the ordered PA14 transposon library revealed 224 mutants unable to surf and very limited overlap with genes required for swarming. Mutants affecting surfing included two downstream effector genes of the stringent stress response, the copper regulator cueR and the quinolone synthase pqsH. Both the cueR and pqsH cloned genes complemented the surfing deficiency of ΔrelAΔspoT. Our study revealed insights into stringent stress dependency in LESB58 and showed that surfing motility is stringently-controlled via the expression of cueR and pqsH. Downstream factors of the stringent stress response are important to investigate in order to fully understand its ability to colonize and persist in the CF lung.

囊性纤维化（CF）是一种遗传性疾病，会影响产生粘蛋白的身体器官，例如肺。CF的特征是产生粘稠的粘稠粘液，其中含有糖蛋白粘蛋白，可导致进行性气道阻塞。最近，我们证明了粘蛋白的存在在运动的细菌中引起了快速的表面适应，这种运动被称为冲浪运动，此处提供的数据表明这与蜂群运动非常不同。铜绿假单胞菌CF是CF中的主要定居病原体，它采用多种压力应对机制来生存CF肺的高粘度环境。我们使用了基于运动的分析方法和RNA-Seq，以研究高毒CF分离株LESB58（利物浦流行株）中的严格胁迫反应。蠕动实验揭示的LESB58严禁反应突变体（Δ RELA Δ点）无法冲浪。Δ的转录谱RELA Δ点与来自冲浪边缘的野生型细胞相比，来自冲浪琼脂板的突变细胞揭示了2584个失调的基因。基因本体论和KEGG富集分析揭示了严格应答对氨基酸，核酸和脂肪酸代谢，TCA循环和糖酵解，VI型分泌以及趋化性，细胞通讯，铁转运，氮代谢过程和循环二糖的影响-GMP信令。有序的PA14转座子文库的筛选显示224个突变体无法冲浪，并且与群体所需的基因重叠非常有限。影响冲浪的突变体包括严格的应激反应的两个下游效应基因，铜调节剂cueR和喹诺酮合酶pqsH。无论是CUER和pqsH克隆的基因补充Δ的冲浪不足RELA Δ点。我们的研究揭示了对LESB58中严格的压力依赖性的见解，并表明冲浪运动受cueR和pqsH的表达严格控制。为了充分了解其在CF肺中定居和持续的能力，对严格的压力反应的下游因素进行研究很重要。