Symbiosis within symbiosis: evolving nitrogen-fixing legume symbionts

Philippe Remigi, Jun Zhu, J Peter W Young, Catherine Masson-Boivin

Research output: Contribution to journalArticlepeer-review


Bacterial accessory genes are genomic symbionts with an evolutionary history and future that is different from that of their hosts. Packages of accessory genes move from strain to strain and confer important adaptations, such as interaction with eukaryotes. The ability to fix nitrogen with legumes is a remarkable example of a complex trait spread by horizontal transfer of a few key symbiotic genes, converting soil bacteria into legume symbionts. Rhizobia belong to hundreds of species restricted to a dozen genera of the Alphaproteobacteria and Betaproteobacteria, suggesting infrequent successful transfer between genera but frequent successful transfer within genera. Here we review the genetic and environmental conditions and selective forces that have shaped evolution of this complex symbiotic trait.

Original languageEnglish
Pages (from-to)63-75
Number of pages13
JournalTrends in microbiology
Issue number1
Publication statusPublished - 21 Nov 2015

Bibliographical note

Copyright © 2015 Elsevier Ltd. All rights reserved.

Cite this