The present work comprehensively analyzed the transcriptome and phenotypes that were regulated by c-di-GMP in P. syringae . Given that the majority of diguanylate cyclases and phosphodiesterases have not been characterized in P. syringae , this work provided a very useful database for the future study on regulatory mechanism (especially its relationship with T3SS) of c-di-GMP in P. syringae . In particular, we identified three promoters that were sensitive to elevated c-di-GMP levels and inserted them into luciferase-based reporters that effectively respond to intracellular levels of c-di-GMP in P. syringae , which could be used as an economic and efficient way to measure relative c-di-GMP levels in vivo in the future.