Plant Innate Immunity

Abstract

Plants possess an elaborate multi-layered defense system that relies on the intrinsic ability of plant cells to perceive the presence of pathogens and trigger local and systemic responses. Transmembrane receptors detect highly conserved microbial features and activate signaling cascades that induce defense gene expression. Pathogens deliver effector proteins into plant cells that suppress these responses by interfering with signaling components. Plants, in turn, evolved intracellular resistance (R) protein receptors to recognize these effector proteins or their activities in the plant cell. Activated R proteins trigger a series of physiologi- cal changes in the infected cell that restrict pathogen growth locally and resonate systemically to enhance immunity throughout the plant. In this chapter we sum- marize our current understanding of defense responses employed by plants during pathogen infection