Plant Immunity as a Surveillance System to Detect Pathogens
Abstract
Plants are frequently exposed to a variety of pathogenic bacteria at various phases of their life cycle, which pose a threat to their growth and development. The complex innate plant immune system uses two interrelated defense methods based on pathogen awareness to prevent harmful bacteria from growing. The ability of pathogens to modify the post-translational state of host proteins represents a powerful means for the pathogen to tip the balance from immunity to sensitivity. Since most effectors have yet to be assigned an accurate function and given the enormous diversity that exists among those effectors identified to date, the expectation is that the future will see the identification of alternative effector- triggered PTMs and their substrates. However, a bottleneck is now forming in the characterization of effector activities and is likely to build further as whole-genome sequencing projects identify ever-increasing numbers of presumed effectors. The use of proteomics to monitor effector localization and host proteome dynamics is likely to emerge as a pivotal tool that will enable effector activities to be linked with host PTM signaling pathways. An improved understanding of the mechanisms by which pathogens use their effector ranges to manipulate host defense signaling will prove invaluable for developing plant lines with improved pathogen resistance. This review focus on our current understanding of how plant–microbe interactions can activate the sophisticated plant immune system at the molecular level.
