DNA damage-associated vesicle production in Stenotrophomonas maltophilia is mediated by a cryptic tailocin endolysin

Like other Gram-negative bacteria, S. maltophilia is capable of producing membrane vesicles under normal growth conditions. The addition of certain exogenous triggers stimulates the production of vesicles, including those that are distinct from the archetypal outer membrane vesicle. In this study, we examine the effects of DNA damage on vesiculation, with a focus on the role of a bacteriophage-encoded endolysin. We demonstrate that deletion of the gene that encodes this protein (mal) negatively affects the vesiculation capacity of S. maltophilia. Further, we provide evidence that the spontaneous re-arrangement of shattered membrane fragments attributable to mal-induced explosive cell lysis results in the formation of predominantly explosive outer membrane vesicles, while only a minor portion are outer-inner membrane vesicles. Our findings expand on the current knowledge of (cryptic) tailocins in the biogenesis of vesicles in conditions of stress.