An overview of plant resistance to plant-pathogenic bacteria

In an environment rich in potentially harmful plant-pathogenic bacteria, plants must deploy a complex set of defensive responses to prevent successful bacterial infection. A sophisticated plant defense system perceives bacterial elicitors capable of damaging important cellular, biochemical, and physiological functions involved in the growth and development of the host. Within the underlying defense signaling network against bacterial infections, plants have a two-tiered innate immune system, called MAMP-triggered immunity (MTI) and effector-triggered immunity (ETI). Moreover, the plant hormones ethylene, jasmonic acid, and salicylic acid also play a central role in the regulation of plant immune responses by modulating the signaling pathways for systemic resistance. A deep understanding of these multiple defense mechanisms against the attack of pathogenic bacteria has an important practical effect by allowing progress in the development of more robust crops with broad resistance and durability against bacterial diseases. This review focuses on current knowledge about plant defense mechanisms triggered via MTI, ETI, and hormonal signaling related to the plant’s immune response against bacterial pathogens.