Genome-level evolution of resistance genes in Arabidopsis thaliana

Andrew Baumgarten, Steven Cannon, Russ Spangler, Georgiana May

Research output: Contribution to journalArticle

115 Scopus citations

Abstract

Pathogen resistance genes represent some of the most abundant and diverse gene families found within plant genomes. However, evolutionary mechanisms generating resistance gene diversity at the genome level are not well understood. We used the complete Arabidopsis thaliana genome sequence to show that most duplication of individual NBS-LRR sequences occurs at close physical proximity to the parent sequence and generates clusters of closely related NBS-LRR sequences. Deploying the statistical strength of phylogeographic approaches and using chromosomal location as a proxy for spatial location, we show that apparent duplication of NBS-LRR genes to ectopic chromosomal locations is largely the consequence of segmental chromosome duplication and rearrangement, rather than the independent duplication of individual sequences. Although accounting for a smaller fraction of NBS-LRR gene duplications, segmental chromosome duplication and rearrangement events have a large impact on the evolution of this multigene family. Intergenic exchange is dramatically lower between NBS-LRR sequences located in different chromosome regions as compared to exchange between sequences within the same chromosome region. Consequently, once translocated to new chromosome locations, NBS-LRR gene copies have a greater likelihood of escaping intergenic exchange and adopting new functions than do gene copies located within the same chromosomal region. We propose an evolutionary model that relates processes of genome evolution to mechanisms of evolution for the large, diverse, NBS-LRR gene family.

Original languageEnglish (US)
Pages (from-to)309-319
Number of pages11
JournalGenetics
Volume165
Issue number1
StatePublished - Sep 1 2003

    Fingerprint

Cite this

Baumgarten, A., Cannon, S., Spangler, R., & May, G. (2003). Genome-level evolution of resistance genes in Arabidopsis thaliana. Genetics, 165(1), 309-319.