Geraniol attenuates virulence factors by inhibiting quorum sensing of .

is a ubiquitous opportunistic pathogen that can cause severe respiratory tract infections. Geraniol, a chemical component of essential oils, has antimicrobial and anti-inflammatory activities, along with low toxicity. However, the effect and mechanism of geraniol against virulence factors are rarely studied. In this study, we investigated the quorum sensing (QS) inhibitory effects and mechanisms of geraniol against PAO1, using physiological and biochemical techniques, quantitative reverse transcription polymerase chain reaction, and transcriptomics. Geraniol slightly affected PAO1 growth, prolonged the lag phase, and delayed growth periods in a concentration-dependent manner. Geraniol inhibited three QS systems of , , , and by suppressing the expression level of their key genes, including the three signal synthetase encoding genes of , , and , and the corresponding signal receptor encoding genes of , , and . Geraniol also suppressed certain virulence genes regulated by these three QS systems, including , , , , and , resulting in the attenuation of the related virulence factors, rhamnolipids, exoprotease LasA, elastase, lectin, pyocyanin, and biofilm. In conclusion, geraniol can suppress the virulence factors of PAO1 by inhibiting the three QS systems of , , and . This study is significant for improving the treatment of bacterial infections caused by .