skip to main content

DOE PAGESDOE PAGES

Title: Adding biotic complexity alters the metabolic benefits of mutualism

Mutualism is ubiquitous in nature and plays an integral role in most communities. To predict the eco-evolutionary dynamics of mutualism it is critical to extend classic pairwise analysis to include additional species. We investigated the effect of adding a third species to a pair-wise mutualism in a spatially structured environment. We tested the hypotheses that selection for costly excretions in a focal population i) decreases when an exploiter is added ii) increases when a third mutualist is added relative to the pair-wise scenario. We assayed the selection acting on Salmonella enterica when it exchanges methionine for carbon in an obligate mutualism with an auxotrophic Escherichia coli. A third bacterium, Methylobacterium extorquens, was then added and acted either as an exploiter of the carbon or third obligate mutualist depending on the nitrogen source. In the tri-partite mutualism M. extorquens provided nitrogen to the other species. Contrary to our expectations, adding an exploiter increased selection for methionine excretion in S. enterica. Conversely, selection for cooperation was lower in the tri-partite mutualism relative to the pair-wise system. Genome-scale metabolic models helped identify the mechanisms underlying these changes in selection. Our results highlight the utility of connecting metabolic mechanisms and eco-evolutionary dynamics.
Authors:
 [1] ;  [2] ;  [3] ;  [4]
  1. Harvard Univ., Cambridge, MA (United States); Univ. of Minnesota, Minneapolis, MN (United States)
  2. Harvard Univ., Cambridge, MA (United States); Univ. of Oxford (United Kingdom)
  3. Univ. of Minnesota, Minneapolis, MN (United States)
  4. Harvard Univ., Cambridge, MA (United States); Univ. of Idaho, Moscow, ID (United States)
Publication Date:
Grant/Contract Number:
SC0006731
Type:
Accepted Manuscript
Journal Name:
Evolution
Additional Journal Information:
Journal Volume: 70; Journal Issue: 8; Journal ID: ISSN 0014-3820
Publisher:
Wiley
Research Org:
Harvard Univ., Cambridge, MA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES
OSTI Identifier:
1467618
Alternate Identifier(s):
OSTI ID: 1401860