Topics considered in this volume include the importance of horizontal gene transfer in originating new bacterial strains and species and advances in transcriptomics that allow us to describe the complex regulatory networks critical to plant-microbe interactions. The availability of the genome has led to new technologies in genome editing, which will revolutionize approaches to genetic engineering, even in eukaryotes. The contributions show how genomics has greatly accelerated progress toward understanding the biology of these bacteria and how that understanding can be translated into novel crop protection methods.