Phosphodiesterase Genes Regulate Amylovoran Production, Biofilm Formation, and Virulence in Erwinia amylovora

Abstract

Precise control of the expression of virulence genes is essential for successful infection of apple hosts by the fire blight pathogen, Erwinia amylovora . The presence and buildup of a signaling molecule called cyclic di-GMP enables the expression and function of some virulence determinants in E. amylovora , such as amylovoran production and biofilm formation. However, other determinants, such as those for motility and the type III secretion system, are expressed and functional when cyclic di-GMP is absent. Here, we report studies of enzymes called phosphodiesterases, which function in the degradation of cyclic di-GMP. We show the importance of these enzymes in virulence gene regulation and the ability of E. amylovora to cause plant disease.