Abstract
A number of plant-associated bacteria possess transcription factors homologous to LuxR that respond to compounds found in plant tissue. These LuxR homologs are known to regulate virulence or symbiosis. Although the first of these proteins were described more than a decade ago, the factors they respond to remain unknown. Here we identify a compound that functions with PipR, a plant-responsive LuxR homolog from a tree root endopytic Pseudomonas isolate. The inducer is an ethanolamine derivative. Ethanolamine is a building block for plant membrane phospholipids and signaling molecules. This discovery connects at least one of the plant-responsive LuxR homolog systems to a growing understanding of ethanolamine chemistry and responses of bacterial cells to ethanolamine and ethanolamine derivatives.
