Genomic and population biology of dehalogenating Chloroflexi in deep sea sediments using single cell sorting and genome amplification

• Applicant: Professorin Dr. Anne-Kristin Kaster
• Subject Area: Microbial Ecology and Applied Microbiology
• Term: from 2012 to 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 221104321

Dehalogenating Chloroflexi, such as Dehalococcoides (Dhc), were originally discovered as the key microbes mediating reductive dehalogenation of the prevalent groundwater contaminants tetrachloroethene and trichloroethene to ethene. Recently, these microbes have also been recognized in a number of non-contaminated deep sea sediments. Molecular and genomic studies on the key enzymes reductive dehalogenases, encoded by rdh genes, have provided evidence for a rapid adaptive evolution of Dhc and rdh towards degradation of anthropogenic organohalogens. However, the metabolic life style of Dhc in the absence of said contaminants remains unknown. In order to provide fundamental insights into the (eco)physiology, genomic population structure and evolution of this unique and important microbial species, it is of great interest to analyse dehalogenating Chloroflexi as they naturally occur in non-contaminated marine subsurfaces. Derived correlations may not only provide unprecedented biological insights into abundant deep sea sediment microbes, but also help assess biodegradative potential for reductive dehalogenation and allow for the identification of optimal engineering conditions, leading to a more effective management of bioremediation strategies. In addition, this research will be able to answer questions about life within the poorly understood oligotrophic marine subsurface. I therefore propose to conduct single cell and molecular genomics on dehalogenating Chloroflexi in deep sea sediment samples, which enable the culture-independent characterization of slow growing microbes directly from natural environments. This research will provide me with the invaluable opportunity to work on rare and unique samples, which are aptly suited for my investigatory purposes as well as apply state of the art tools to study fundamental aspects of microbial biology, which have so far escaped traditional approaches.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professor Dr. Alfred Spormann