Ecology and Evolution

Evolution of syntrophy at the single cell level

Previously, a two-organism model community was established under sulfate-deplete conditions that prevented independent growth of Desulfovibrio vulgaris (Dv) by sulfate respiration (SR), and required its syntrophic interaction with Methanococcus maripaludis (Mm) to support growth of both organisms (Hillesland & Stahl, 2010).  ‘Syntrophy’ (ST) is an obligate mutualism in which, here, the oxidation of the organic substrate (lactate) by Dv is energetically feasible only if its fermentation products (primarily hydrogen (H2) and formate) are consumed by Mm.  Twelve lines of this model community were further subjected to 1000 generations of experimental evolution. Growth characteristics across all 12 lines improved significantly around 300 generations (Hillesland & Stahl, 2010). Whole genome sequencing revealed that many mutations had accumulated in the genomes of both organisms across all 12 lines. Analysis of mutations showed that specialization for ST across nearly all lines came at the expense (tradeoff) of erosion of SR (Hillesland et al, 2014).  We are currently investigating if there was any evidence of co-evolution during evolution of syntrophy by using single cell sequencing. Ultimately, we would like to develop a single cell lineage mapping of mutations accumulated to predict emergence and co-evolution of syntrophy. This will also drive development of single cell computational methods and algorithms to build gene regulatory network modeling at the single cell level.



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Turkarslan, Serdar, David J. Reiss, Goodwin Gibbins, Wan Lin Su, Min Pan, J. Christopher Bare, Christopher L. Plaisier, and Nitin S. Baliga. “Niche Adaptation by Expansion and Reprogramming of General Transcription Factors.” Molecular Systems Biology 7 (2011): 554. Cite
Hillesland, Kristina L., Sujung Lim, Jason J. Flowers, Serdar Turkarslan, Nicolas Pinel, Grant M. Zane, Nicholas Elliott, et al. “Erosion of Functional Independence Early in the Evolution of a Microbial Mutualism.” Proceedings of the National Academy of Sciences of the United States of America 111, no. 41 (October 14, 2014): 14822–27. Cite
Thompson, Anne W., Matthew J. Crow, Brian Wadey, Christina Arens, Serdar Turkarslan, Sergey Stolyar, Nicholas Elliott, et al. “A Method to Analyze, Sort, and Retain Viability of Obligate Anaerobic Microorganisms from Complex Microbial Communities.” Journal of Microbiological Methods 117 (October 2015): 74–77. Cite
Beer, Karlyn D., Elisabeth J. Wurtmann, Nicolas Pinel, and Nitin S. Baliga. “Model Organisms Retain an ‘Ecological Memory’ of Complex Ecologically Relevant Environmental Variation.” Applied and Environmental Microbiology 80, no. 6 (March 2014): 1821–31. Cite