The stabilization of quorum sensing (QS) is vital for bacterial survival in various environments. Although the mechanisms of QS stabilization in certain conditions have been well studied, the impact of environmental factors has received much less attention. In this study, we show that the supplementation of 25 µM iron in competition experiments and 50 µM in evolution experiments to casein growth cultures significantly increased the possibility of population collapse by affecting elastase production. However, the expression of lasI and lasR remained constant regardless of iron concentration and hence this effect was not through interference with the LasIR circuit, which mainly regulates the secretion of elastase in Pseudomonas aeruginosa. However, the expression of rhlR was significantly inhibited by iron treatment, which could affect the production of elastase. Further, based on both reverse transcription quantitative polymerase chain reaction and gene knock-out assays, we show that iron inhibits the transcription of ppyR and enhances the expression of mexT, both of which decrease elastase production and correspondingly interfere with QS stabilization. Our findings show that environmental factors can affect the genes of QS circuits, interfering with QS stabilization. These findings are not only beneficial in understanding the mechanistic effect of iron on QS stabilization, but also demonstrate the complexity of QS stabilization by linking non-QS-related genes with QS traits.

群体感应（QS）的稳定对于各种环境中的细菌存活至关重要。尽管已经对某些条件下QS稳定化的机制进行了深入研究，但是环境因素的影响却很少受到关注。在这项研究中，我们表明在竞争实验中补充25 µM铁，在进化实验中补充50 µM酪蛋白生长培养物会通过影响弹性蛋白酶的产生显着增加种群崩溃的可能性。但是，无论铁浓度如何，lasI和lasR的表达均保持恒定，因此该作用不是通过干扰LasIR电路实现的，LasIR电路主要调节铜绿假单胞菌中弹性蛋白酶的分泌。然而，铁处理显着抑制了rhlR的表达，这可能影响弹性蛋白酶的产生。此外，基于两个反转录定量聚合酶链式反应和基因敲除实验，我们表明，铁抑制的转录ppyR和增强的表达文部科学省，这两者减少弹性蛋白酶的生产和相应地与QS稳定干扰。我们的发现表明，环境因素会影响QS电路的基因，从而干扰QS的稳定性。这些发现不仅有益于了解铁对QS稳定的机械作用，而且通过将非QS相关基因与QS性状联系起来，证明了QS稳定的复杂性。