Regulation and Function of a Mutualistic Bacterial Host Range Specificity Determinant

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

All plant and animal hosts associate with microbial symbionts that can contribute to health or cause disease. Many microbe-host associations (both beneficial and pathogenic) are specific; only a single species or strain of microbe exists in close association with a single host or tissue. A fundamental but unanswered biological question is what allows some microbes but not others to colonize specific hosts or tissues. This research investigates how bacteria and animal symbiotic partners recognize each other while excluding unwanted species. The bacterium being studied colonizes the intestine of a small soil-dwelling roundworm (nematode) , and expresses traits beneficial for the nematode. The project focuses on a bacterial membrane protein that is necessary for colonization and dictates specificity for certain nematode species. This protein represents a family of proteins present in many symbionts that colonize animal mucosae. Genetic, biochemical, physical, and microscopy approaches will be used to reveal the structure, biochemical function, and interacting host factors of the protein. In general, the work will hasten technical advances for investigating an understudied class of membrane proteins. Also, the research will provide paradigms that yield broad insights into the molecular basis of microbial colonization of animals and what might allow microbes to expand beyond their current colonization ranges and enter new hosts or tissue sites. The public will be exposed to this research through community seminars and high school outreach programs. The project encompasses the NSF-recommended five core concepts for undergraduate education, and will be used to generate an integrated curriculum emphasizing these areas. Undergraduate, graduate, and post-doctoral apprentices will be trained in the areas of structural biology, molecular biology, nematology, and bacteriology through direct scientific inquiry. Thus, this project will provide fundamental knowledge of bacterial interactions with animal hosts, and will help train future scientists with expertise to further apply this knowledge.