Genetic regulation of the Roseobacter swim-or-stick lifestyle

University Of Maryland Baltimore County, Baltimore MD

Investigators

Abstract

Members of the Roseobacter clade are among the most abundant and ecologically relevant marine bacteria. Some roseobacters live on the surface of small marine algae (phytoplankton, dinoflagellates), and the long-term goal of this research is to understand how they establish and maintain their symbiosis with these phytoplankton cells. These bacteria have a biphasic lifestyle that includes a motile phase that is attracted to the dinoflagellate, and a sessile stage that loses flagella, synthesizes adhesive proteins, and forms biofilms on the host. The sessile cells produce an antibacterial compound (TDA) that likely inhibits competing bacteria and promotes the growth of the host. The Belas lab has used genetic and molecular techniques to discover two genes that that play major roles in this "swim-or-stick" life-style. One gene complex controls motility, while the other controls production of the antibiotic. Understanding how these genes operate and are regulated will significantly increase our understanding of how bacterial motility and colonization are controlled, key issues for both the marine environment and for understanding the spread of pathogens. On a broader scale, the dinoflagellates produce a compound (DMSP) that the bacteria convert to dimethyl sulfide (DMS); DMS in the atmosphere is thought to play a role in climate control. The results of this research will be incorporated in educational programs to train high school teachers, graduate, undergraduate and high school students, many of whom are underrepresented minorities and women, as well as to provide community "K-to-gray" outreach, involving students of all ages.