Quorum Quenching Lactonase Alters Virulence of <i>Pectobacterium atrosepticum</i> and Reduces Maceration in Potatoes

<i>Pectobacterium atrosepticum</i> is a soft rot phytopathogenic bacterium mainly infecting potatoes. The virulence of <i>P. atrosepticum</i> is controlled by quorum sensing (QS), a communication mechanism which enables bacteria to coordinate their behavior in a population density-dependent manner. Inhibiting QS has gained interest as a sustainable alternative to conventional treatments to control pathogens in agriculture. Here, we investigate the potential of a robust lactonase to inhibit <i>P. atrosepticum</i> virulence in vitro, combining phenotypic and proteomic studies. We report that exogenous lactonase treatment reduced the secretion of pectate lyase, cellulase, and polygalacturonase enzymes, leading to decreased virulence on potato tubers. Major changes in the <i>P. atrosepticum</i> proteome revealed that lactonase affects the abundance of proteins with various functions, including virulence. Taken as a whole, these results suggest that lactonase-mediated disruption of QS in <i>P. atrosepticum</i> is a promising strategy to limit <i>P. atrosepticum</i> infections.