The contents of this course will cover two major components of plant-pathogen interactions, the first part of the course will cover the mechanisms and strategies used by plant pathogens to colonize plant tissues (pathogenesis) and the second part will focus on host plant defenses and responses against the invading pathogen (s) (host defenses). General principles and specific interactions using selected pathosystems will be used to illustrate microbial pathogenesis strategies. Interactions with economic significance and level of available knowledge will be chosen for detailed analysis. We will also highlight non-pathogenic interactions. Emphasis on this course will be on basic understanding of the cellular and molecular mechanisms of host pathogen interactions and genetics of plant pathogenesis covering milestone and recent advances in the area of plant pathogenesis.