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Abstract：
The Pseudomonas aeruginosa strain PAO1 has routinely been used as a laboratory model for quorum sensing (QS). However, the microevolution of P. aeruginosa laboratory strains resulting in genetic and phenotypic variations have caused inconsistencies in QS research. To investigate the underlying causes of these variations, we analyzed 5 Pseudomonas aeruginosa PAO1 sublines from our laboratory using a combination of phenotypic characterization, high throughput genome sequencing, and bioinformatic analysis. The major phenotypic variations among the sublines spanned across the levels of QS signals and virulence factors such as pyocyanin and elastase. Furthermore, the sublines exhibited distinct variations in motility and biofilm formation. Most of the phenotypic variations were mapped to mutations in the lasR and mexT, which are key components of the QS circuit. By introducing these mutations in the subline PAO1-E, which is devoid of such mutations, we confirmed their influence on QS, virulence, motility, and biofilm formation. The findings further highlight a possible divergent regulatory mechanism between the LasR and MexT in the P. aeruginosa. The results of our study reveal the effects of microevolution on the reproducibility of most research data from QS studies and further highlight mexT as a key component of the QS circuit of P. aeruginosa.
摘要：
铜绿假单胞菌菌株PAO1通常被用作群体感应（QS）的实验室模型。然而,铜绿假单胞菌实验室菌株的微进化导致遗传和表型变异，在QS研究中引起了不一致。为了调查这些变化的根本原因，我们分析了5个铜绿假单胞菌PAO1亚系从我们的实验室使用的表型特征的组合，高通量基因组测序，和生物信息学分析。亚系之间的主要表型变异跨越QS信号和毒力因子的水平，例如绿脓苷和弹性蛋白酶。此外，子系在运动和生物膜形成方面表现出明显的变化。大多数表型变异被定位到lasR和mexT中的突变，QS电路的关键部件。通过在PAO1-E子系中引入这些突变，没有这种突变，我们证实了它们对QS的影响,毒力,运动性,和生物膜的形成。该发现进一步突出了铜绿假单胞菌中LasR和MexT之间可能的不同调节机制。我们的研究结果揭示了微观进化对QS研究中大多数研究数据的可重复性的影响，并进一步强调了mexT是铜绿假单胞菌QS回路的关键组成部分。
