Infection route in tomato roots and quorum sensing of Ralstonia pseudosolanacearum strain OE1-1

The soil-borne Gram-negative beta-proteobacterium Ralstonia pseudosolanacearum strain OE1-1 attaches to the epidermis of elongation zones in tomato roots and colonizes intercellular spaces between the epidermis and cortex, activating quorum sensing (QS). This QS activation leads to infection of OE1-1 in cell wall-degraded cortical cells and its formation of mushroom-shaped biofilms to subsequently infect xylem vessels and exhibit virulence. QS consists of two pathways for the induction and activation, respectively, of the LysR family transcriptional regulator PhcA. The QS-inducible secondary metabolites ralfuranones and the major exopolysaccharide EPS I, and a lectin, LecM, are associated with the positive feedback loop of QS.

Automated summary

The Gram-negative bacterium Ralstonia pseudosolanacearum strain OE1-1 attaches to tomato roots, activates quorum sensing, and forms biofilms to infect xylem vessels. Quorum sensing involves the induction and activation of the transcriptional regulator PhcA, and is associated with the production of secondary metabolites and exopolysaccharides. These components contribute to the positive feedback loop of quorum sensing.