Eukaryotes constantly interact with an abundant array of different microbes. These interactions can drastically impact the fate, evolution, and responses of both partners in multifaceted ways. Understanding the diverse interactions between bacteria and eukaryotes and their underlying mechanisms can provide insight into host resistance strategies, bacterial pathogenesis, and mutual cooperation. Interestingly, carrier clones of the social amoeba Dictyostelium discoideum have been shown to harbor a variety of bacteria, in contrast to their non-carrier counterparts. In the host, these bacteria provide food and defense. In non-carrier clones, these bacteria are pathogenic. D. discoideum is amenable to a variety of biological techniques, can be infected by important human pathogens, and displays distinct and diverse interactions with a variety of microbial species. These attributes make it a powerful system for probing the eukaryote-bacteria interface. The purpose of my research is to define the differential interactions between D. discoideum clones with bacterial species, and to identify the genes and co-evolutionary trajectories underlying these interactions and their associated outcomes.
My specific aims are to: 1. Determine the differential responses of carrier and non-carrier Dictyostelium discoideum amoeba clones to bacterial pathogenesis. 2. Examine the impact of amoeba- bacteria co-evolution on both partners. 3. Identify genes involved in the amoeba- bacteria interface. Through this work I will set up the framework to better define this model system, gain insight into evolutionary pressures in the development and breakdown of eukaryote-microbe cooperation, and identify genes involved in host-microbe mutualism. This flexible system can be further applied to refine our understanding of the evolutionary pathways that specify the fine line between infection and colonization/cooperation and the role of differential host-responses in these events. Finally, this work will pave the way for more in-depth analysis of the molecular mechanisms involved in the amoeba-bacterial interface, thereby allowing for greater resolution of the dynamic causes and consequences of trans- kingdom interactions along the wider symbiosis continuum.

Public Health Relevance

Humans and other organisms are colonized by an abundant array of different microbes, referred to as an organisms microbiota. The interactions between a host and its associated microbes can drastically impact organismal fitness in multifaceted ways. Understanding the genetic and evolutionary pathways underlying these interactions will provide insight into both beneficial and detrimental host microbe associations, specify the line between infection and cooperation, and clarify the role of host responses in these events

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
5F32GM108414-02
Application #
8701889
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Hoodbhoy, Tanya
Project Start
2013-08-01
Project End
2016-07-31
Budget Start
2014-08-01
Budget End
2015-07-31
Support Year
2
Fiscal Year
2014
Total Cost
Indirect Cost
Name
Washington University
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
DiSalvo, Susanne; Haselkorn, Tamara S; Bashir, Usman et al. (2015) Burkholderia bacteria infectiously induce the proto-farming symbiosis of Dictyostelium amoebae and food bacteria. Proc Natl Acad Sci U S A 112:E5029-37
DiSalvo, Susanne; Brock, Debra A; Smith, Jeff et al. (2014) In the social amoeba Dictyostelium discoideum, density, not farming status, determines predatory success on unpalatable Escherichia coli. BMC Microbiol 14:328