ISOPRENE SYNTHASE GENES FORM A MONOPHYLETIC CLADE OF ACYCLIC TERPENE SYNTHASES IN THE TPS-B TERPENE SYNTHASE FAMILY
Article first published online: 20 DEC 2012
© 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.
Volume 67, Issue 4, pages 1026–1040, April 2013
How to Cite
Sharkey, T. D., Gray, D. W., Pell, H. K., Breneman, S. R. and Topper, L. (2013), ISOPRENE SYNTHASE GENES FORM A MONOPHYLETIC CLADE OF ACYCLIC TERPENE SYNTHASES IN THE TPS-B TERPENE SYNTHASE FAMILY. Evolution, 67: 1026–1040. doi: 10.1111/evo.12013
- Issue published online: 3 APR 2013
- Article first published online: 20 DEC 2012
- Accepted manuscript online: 26 NOV 2012 04:03PM EST
- Received January 23, 2012 Accepted October 30, 2012
- chemical mechanism;
- isoprene synthase;
Many plants emit significant amounts of isoprene, which is hypothesized to help leaves tolerate short episodes of high temperature. Isoprene emission is found in all major groups of land plants including mosses, ferns, gymnosperms, and angiosperms; however, within these groups isoprene emission is variable. The patchy distribution of isoprene emission implies an evolutionary pattern characterized by many origins or many losses. To better understand the evolution of isoprene emission, we examine the phylogenetic relationships among isoprene synthase and monoterpene synthase genes in the angiosperms. In this study we identify nine new isoprene synthases within the rosid angiosperms. We also document the capacity of a myrcene synthase in Humulus lupulus to produce isoprene. Isoprene synthases and (E)-β-ocimene synthases form a monophyletic group within the Tps-b clade of terpene synthases. No asterid genes fall within this clade. The chemistry of isoprene synthase and ocimene synthase is similar and likely affects the apparent relationships among Tps-b enzymes. The chronology of rosid evolution suggests a Cretaceous origin followed by many losses of isoprene synthase over the course of evolutionary history. The phylogenetic pattern of Tps-b genes indicates that isoprene emission from non-rosid angiosperms likely arose independently.