The coevolutionary arms race between pathogen and plant host

Wenwan Lu, Darrell Desveaux


The coevolutionary arms race between pathogen and plant host has prompted diverse pathogen virulence strategies and has modified plant surveillance and defense systems. Different models have been postulated to explain the pathogen-host interaction over evolutionary history. A classic bacterial pathogen, Pseudomonas syringae , utilizes the Type III secretion system to translocate its effectors into the plant cell to enhance bacterial virulence. During evolutionary time, the plant host evolved Resistance protein (R protein) in order to trigger a Hypersensitive Response (HR) to terminate the pathogenic virulence function.The bacterial pathogen retaliates by evolving new effectors to evade host innate immune response. This paper examines three different models of the host-pathogen system by discussing the roles of Type III secretion system effectors (T3SEs), host targets and R proteins in the plant surveillance system. Understanding the specific host-pathogen interaction is crucial to the improvement of agriculture, food, and biofuel production.


type III secretion system; transgenic plants; type III secreted protein; the Decoy model; the Guard model; receptor-ligand model

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© University of Toronto Journal of Undergraduate Life Sciences.