Can plants manipulate bacterial quorum sensing?

Abstract

This paper originates from an address at the 8th International Symposium on Nitrogen Fixation with Non-Legumes, Sydney, NSW, December 2000 Higher plants have been found to secrete a variety of unknown signal-mimic compounds that can stimulate or inhibit behaviors in bacteria, which are regulated by N-acyl homoserine lactone (AHL) signal molecules. A wide range of bacterial species use AHLs or other signal molecules to regulate the expression of many of their genes in response to changes in population density. Thus, the ability of higher plants to specifically alter AHL-regulated behavior in bacteria by production of AHL signal-mimic compounds could be of broad consequence. We briefly review what is known about AHL signaling in bacteria and the synthesis of AHL signal-mimic compounds by plants, and then consider some of the important questions concerning the roles these plant signal-mimic compounds may play in natural encounters between plants and bacteria.