LAUSR

Abstract The antibacterial action of pomegranate peel against plant pathogen Ralstonia solanacearum has been focused in this study. We identified the chemical composition of pomegranate peel polyphenols (PPPs) and expanded their antibacterial spectrum by adding a new member R. solanacearum. PPPs were consisting of punicalagin, ellagic acid, catechin, gallic acid, epicatechin, and chlorogenic acid. Although the monomers exhibited strong antibacterial effect, PPPs performed better than individual ones. PPPs significantly hindered bacterial multiplication and swimming motility, and severely weakened the stability and integrity of the cell membrane. Bacterial biofilm formation was affected by PPPs in both time and concentration dependent manners. Punicalagin could bind the functional domains of bacterial transcriptional regulator PhcA when cell membrane integrity was impaired, resulting in the disordered regulation network and successive bacterial damage. We delineated the antibacterial mechanism of PPPs on both cell and molecular level with the aid of state of art analysis method and technology.