Genome-enabled Tools to Understand Symbiosis and Encourage “Learn by Doing”

Research on host-microbe interactions has overwhelmingly favored pathogenic associations over the far more ubiquitous beneficial associations. The fact is, all animals and plants require beneficial microbes in order to properly develop, process nutrients, and survive. The relationship between the bioluminescent marine bacterium Vibrio fischeri and its squid host, Euprymna scolopes, has emerged as a powerful model system for understanding the mechanisms by which both beneficial and pathogenic microbes establish and maintain associations with animals and plants. Thanks to expanding genomic databases, including the full genome sequence of V. fischeri, we now have unprecedented access to the inner workings of thousands of microbes in order to compare them and link specific genes to their functions. With funding from the National Science Foundation, students in Dr. Fidopiastis’ Bio 462 (Senior Project Research) and BIO 475 (Molecular Biology) courses, and collaborators from the University of New Hampshire (UNH) constructed a large library of V. fischeri strains, each with a unique mutation in their genome. Our collaborators at UNH, and students in BIO 475 and Dr. Michael Black’s BIO 501 (Graduate Molecular and Cellular Biology) course, use various molecular tools to identify the mutated gene in each of these strains in order to create a database. Once we identify the mutation in each strain, students in MCRO 424 (Microbial Physiology) generate hypotheses as to what phenotype each strain should possess, and then they perform experiments to test their hypotheses. Students then present their work on mutant physiology as a formal presentation to their classmates and write a manuscript in Journal of Bacteriology format. Once strains with novel phenotypes are identified, we can study the ability of mutant strains to colonize squid. This Digital Commons@ Cal Poly site represents a selection of the products (presentations, data, and/or full manuscripts) from infusing “real research” into the classroom; it truly embodies the Cal Poly “Learn by Doing” motto.