Lausanne

Microbial pathogens and herbivores that cause disease or inflict damage to plants are ubiquitous in nature. To withstand and counteract invasions by these, plants have evolved several overlapping layers of defense. A preformed barrier consisting of physical impediments and toxic secondary metabolites limits the progress of most attackers. If these are overcome, a second line of inducible defense responses can be activated in plants through the recognition of non-self structures. Enormous progress has been made in the field of plant pathology over the last decades. Many of the mechanism by which plants perceive pathogens and pests, and the downstream signaling events that ultimately lead to immune responses have been characterized on a molecular level. Yet a comprehensive understanding for how plants can fend off invaders and achieve immunity with such finesse remains to be attained. Two aspects of plant immunity are addressed in this thesis: I) the cell-to-cell communication that governs local defense and II) the genetic machinery and the biochemical processes that underlie wounding and pathogen-induced accumulation of complex lipids. One of the most effective plant defense strategies against parasites is termed hypersensitive respons