Agrobacterium tumefaciens is a soil bacterium that causes crown gall disease in many plants. Surface attachment and biofilm formation are essential for the pathogenesis of this bacterium. Identifying compounds that can inhibit the biofilm formation may enable prevention of its pathogenesis. Pseudomonas aeruginosa can also exist in the soil and has been reported in the same environments as A. tumefaciens. P. aeruginosa can inhibit A. tumefaciens biofilm formation through release of diffusible inhibitors, but the mechanism is unclear. We discovered that the P. aeruginosa siderophores pyoverdine and pyochelin inhibit A. tumefaciens biofilm formation. However, analysis of a P. aeruginosa mutant specifically deficient for pyochelin and pyoverdine production still inhibited A. tumefaciens biofilm formation through additional factors. Chemical characterization of an inhibitor led to the identification of a pyoverdine biosynthetic precursor, previously unrecognized as an iron chelator. It is well known that iron is an essential nutrient for biofilm formation, and iron limitation has been shown to inhibit A. tumefaciens biofilm formation. Our work reveals how P. aeruginosa uses its siderophores and iron chelators to not only acquire iron for its own growth but also to gain competitive advantage over other bacteria. To what extent the iron chelator production plays a role in wild type P. aeruginosa remains under active investigation. Discovering that siderophores and iron chelators inhibit A. tumefaciens biofilm formation could be useful for further applications in plant pathogenesis.

Production and release of an iron-chelating factor by Pseudomonas aeruginosa inhibits biofilm formation by Agrobacterium tumefaciens

Where thousands of chemistry professionals meet to share ideas and advance scientific and technical knowledge. Spring 2023 abstracts, posters, and presentations will launch at the end of March.

ACS Spring 2023

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.