Methods to Study Quorum Sensing-Dependent Virulence and Movement of Phytopathogens In Planta

: Cell-to-cell communication mediated by the diffusible signal factor (DSF) is a common form of gene regulation and plays an important role in virulence of many plant pathogenic bacteria including Xanthomonas spp. Here we describe several approaches to study the involvement of DSF-dependent QS system of the plant pathogenic bacteria Xanthomonas campestris pv. pelargonii (Xhp) as an example of the Xanthomonas spp. The methods described include detection and measurement of DSF, movement in planta, colonization, and aggregate formation.