Journal article
Dynamic genomic architecture of mutualistic cooperation in a wild population of Mesorhizobium
The ISME Journal, Vol.13(2), pp.301-315
02/2019
Handle:
https://hdl.handle.net/2376/110111
PMCID: PMC6331556
PMID: 30218020
Abstract
Research on mutualism seeks to explain how cooperation can be maintained when uncooperative mutants co-occur with cooperative kin. Gains and losses of the gene modules required for cooperation punctuate symbiont phylogenies and drive lifestyle transitions between cooperative symbionts and uncooperative free-living lineages over evolutionary time. Yet whether uncooperative symbionts commonly evolve from within cooperative symbiont populations or from within distantly related lineages with antagonistic or free-living lifestyles (i.e., third-party mutualism exploiters or parasites), remains controversial. We use genomic data to show that genotypes that differ in the presence or absence of large islands of symbiosis genes are common within a single wild recombining population of
Mesorhizobium
symbionts isolated from host tissues and are an important source of standing heritable variation in cooperation in this population. In a focal population of
Mesorhizobium
, uncooperative variants that lack a symbiosis island segregate at 16% frequency in nodules, and genome size and symbiosis gene number are positively correlated with cooperation. This finding contrasts with the genomic architecture of variation in cooperation in other symbiont populations isolated from host tissues in which the islands of genes underlying cooperation are ubiquitous and variation in cooperation is primarily driven by allelic substitution and individual gene gain and loss events. Our study demonstrates that uncooperative mutants within mutualist populations can comprise a significant component of genetic variation in nature, providing biological rationale for models and experiments that seek to explain the maintenance of mutualism in the face of non-cooperators.
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Details
- Title
- Dynamic genomic architecture of mutualistic cooperation in a wild population of Mesorhizobium
- Creators
- Stephanie S Porter - Vancouver, WA 98686 USAJoshua Faber-Hammond - Vancouver, WA 98686 USAAngeliqua P Montoya - Vancouver, WA 98686 USAMaren L Friesen - East Lansing, MI 48824 USACynthia Sackos - Vancouver, WA 98686 USA
- Publication Details
- The ISME Journal, Vol.13(2), pp.301-315
- Academic Unit
- Plant Pathology, Department of; Biological Sciences, School of
- Publisher
- Nature Publishing Group UK; London
- Identifiers
- 99900547245501842
- Language
- English
- Resource Type
- Journal article