The evolution of host-symbiont dependence

Roberta M. Fisher*, Lee M. Henry, Charlie K. Cornwallis, E. Toby Kiers, Stuart A. West

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

Organisms across the tree of life form symbiotic partnerships with microbes for metabolism, protection and resources. While some hosts evolve extreme dependence on their symbionts, others maintain facultative associations. Explaining this variation is fundamental to understanding when symbiosis can lead to new higher-level individuals, such as during the evolution of the eukaryotic cell. Here we perform phylogenetic comparative analyses on 106 unique host-bacterial symbioses to test for correlations between symbiont function, transmission mode, genome size and host dependence. We find that both transmission mode and symbiont function are correlated with host dependence, with reductions in host fitness being greatest when nutrient-provisioning, vertically transmitted symbionts are removed. We also find a negative correlation between host dependence and symbiont genome size in vertically, but not horizontally, transmitted symbionts. These results suggest that both function and population structure are important in driving irreversible dependence between hosts and symbionts.

Original languageEnglish
Article number15973
JournalNature Communications
Volume8
DOIs
Publication statusPublished - 4 Jul 2017

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Fisher, R. M., Henry, L. M., Cornwallis, C. K., Kiers, E. T., & West, S. A. (2017). The evolution of host-symbiont dependence. Nature Communications, 8, [15973]. https://doi.org/10.1038/ncomms15973