%AGordon, Benjamin [Department of Plant Biology University of Illinois Urbana‐Champaign 505 S. Goodwin Ave. Urbana Illinois 61801]%AKlinger, Christie [Department of Plant Biology University of Illinois Urbana‐Champaign 505 S. Goodwin Ave. Urbana Illinois 61801]%AWeese, Dylan [Department of Biology St. Ambrose University 518 West Locust St Davenport Iowa 52803]%ALau, Jennifer [Kellogg Biological Station and Department of Plant Biology Michigan State University 3700 E. Gull Lake Drive Hickory Corners Michigan 49060]%ABurke, Patricia [Department of Plant Biology University of Illinois Urbana‐Champaign 505 S. Goodwin Ave. Urbana Illinois 61801]%ADentinger, Bryn [Jodrell Laboratory Royal Botanic Gardens Kew Richmond Surrey TW9 3DS United Kingdom]%AHeath, Katy [Department of Plant Biology University of Illinois Urbana‐Champaign 505 S. Goodwin Ave. Urbana Illinois 61801]%BJournal Name: Ecology and Evolution; Journal Volume: 6; Journal Issue: 5; Related Information: CHORUS Timestamp: 2023-09-18 06:01:55 %D2016%IWiley Blackwell (John Wiley & Sons) %JJournal Name: Ecology and Evolution; Journal Volume: 6; Journal Issue: 5; Related Information: CHORUS Timestamp: 2023-09-18 06:01:55 %K %MOSTI ID: 10196917 %PMedium: X %TDecoupled genomic elements and the evolution of partner quality in nitrogen‐fixing rhizobia %XAbstract

Understanding how mutualisms evolve in response to a changing environment will be critical for predicting the long‐term impacts of global changes, such as increased N (nitrogen) deposition. Bacterial mutualists in particular might evolve quickly, thanks to short generation times and the potential for independent evolution of plasmids through recombination and/orHGT(horizontal gene transfer). In a previous work using the legume/rhizobia mutualism, we demonstrated that long‐term nitrogen fertilization caused the evolution of less‐mutualistic rhizobia. Here, we use our 63 previously isolated rhizobium strains in comparative phylogenetic and quantitative genetic analyses to determine the degree to which variation in partner quality is attributable to phylogenetic relationships among strains versus recent genetic changes in response to N fertilization. We find evidence of distinct evolutionary relationships between chromosomal andpSym genes, and broad similarity betweenpSym genes. We also find thatnifDhas a unique evolutionary history that explains much of the variation in partner quality, and suggest MoFe subunit interaction sites in the evolution of less‐mutualistic rhizobia. These results provide insight into the mechanisms behind the evolutionary response of rhizobia to long‐term N fertilization, and we discuss the implications of our results for the evolution of the mutualism.

%0Journal Article