Grant: Discovery Grants Program - Individual

A critical problem in microbiology is to understand how bacteria cause diseases in their hosts (i.e. animals and humans). One important mechanism is related to the way bacteria secrete proteins into the environment. To date, studies of protein secretion systems in bacteria have revealed at least six different types of protein secretion machineries, namely types I to VI. Pathogens use these secretion systems, often a number of them simultaneously, to deliver disease-causing proteins (virulence factors) to either the surroundings or directly into host cells. Type VI secretion system (T6SS) and its key role in causing diseases, was first reported in 2006 and subsequently has been shown to be present in many important pathogens. Ours is one of the few laboratories worldwide with considerable expertise on T6SSs, having already accumulated substantial amounts of preliminary experimental data. The current proposal aims to examine in detail the T6SSs in Edwardsiella tarda, a pathogen that can infect both humans and aquatic animals. Fish mortality caused by this organism has led to severe losses in the aquaculture industry worldwide. We will study the regulation and effector functions of these T6SS proteins in order to examine the mechanism of this novel secretion system. Knowledge generated will be important to understand pathogen-host interactions as well as for the development of biotechnological and therapeutics application. This research therefore, is of global importance, and will promote the knowledge-based economy in Canada.