TRADE-OFFS, SPATIAL HETEROGENEITY, AND THE MAINTENANCE OF MICROBIAL DIVERSITY
Article first published online: 24 SEP 2012
© 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.
Volume 67, Issue 2, pages 599–608, February 2013
How to Cite
Porter, S. S. and Rice, K. J. (2013), TRADE-OFFS, SPATIAL HETEROGENEITY, AND THE MAINTENANCE OF MICROBIAL DIVERSITY. Evolution, 67: 599–608. doi: 10.1111/j.1558-5646.2012.01788.x
- Issue published online: 28 JAN 2013
- Article first published online: 24 SEP 2012
- Accepted manuscript online: 3 SEP 2012 11:57AM EST
- Received April 6, 2012 Accepted August 9, 2012 Data Archived: Dryad doi:10.5061/dryad.g1t69
- genetic variation;
- life-history evolution;
Specialization and concomitant trade-offs are assumed to underlie the non-neutral coexistence of lineages. Trade-offs across heterogeneous environments can promote diversity by preventing competitive exclusion. However, the importance of trade-offs in maintaining diversity in natural microbial assemblages is unclear, as trade-offs are frequently not detected in artificial evolution experiments. Stressful conditions associated with patches of heavy-metal enriched serpentine soils provide excellent opportunities for examining how heterogeneity may foster genetic diversity. Using a spatially replicated design, we demonstrate that rhizobium bacteria symbiotic with legumes inhabiting contrasting serpentine and nonserpentine soils exhibit a trade-off between a genotype's nickel tolerance and its ability to replicate rapidly. Furthermore, we detected adaptive divergence in rhizobial assemblages across soil type heterogeneity at multiple sites, suggesting that this trade-off may promote the coexistence of phenotypically distinct bacterial lineages. Trade-offs and adaptive divergence may be important factors maintaining the tremendous diversity within natural assemblages of bacteria.