An inhibitor of the adaptability of Pseudomonas fluorescens in a high-salt environment. Phenomenon and mechanism of inhibition

Pseudomonas fluorescens is a spoilage bacterium in food that has the ability to maintain growth and reproduction in high-salt environments. It acts as a defence mechanism through the exclusion of ions and the formation of biofilms. Hence, disrupting this defence mechanism may be a good way to control food spoilage. In this study, a specific flavonoid small molecule baicalin was found, which was able to dismantle the defence mechanism of the bacteria at a lower concentration (400 μM) of treatment. In synergy with salt, baicalin showed a significant inhibitory effect on the growth, c-di-gmp synthetics and biofilm formation of Pseudomonas fluorescens Pf08. Through transcriptomics, we also found that baicalein interfered with bacterial transport and polysaccharide production functions. Through molecular docking and QPCR, we found that baicalin is able to binding with the RpoS protein through hydrogen bonding and thus interfere with its function.