title: Evidence for an Early Origin of Vernalization Responsiveness in Temperate Pooideae Grasses.
abstract: The ability of plants to match their reproductive output with favorable environmental conditions has major consequences both for lifetime fitness and geographic patterns of diversity. In temperate ecosystems, some plant species have evolved the ability to use winter nonfreezing cold (vernalization) as a cue to ready them for spring flowering. However, it is unknown how important the evolution of vernalization responsiveness has been for the colonization and subsequent diversification of taxa within the northern and southern temperate zones. Grasses of subfamily Pooideae, including several important crops, such as wheat (Triticum aestivum), barley (Hordeum vulgare), and oats (Avena sativa), predominate in the northern temperate zone, and it is hypothesized that their radiation was facilitated by the early evolution of vernalization responsiveness. Predictions of this early origin hypothesis are that a response to vernalization is widespread within the subfamily and that the genetic basis of this trait is conserved. To test these predictions, we determined and reconstructed vernalization responsiveness across Pooideae and compared expression of wheat vernalization gene orthologs VERNALIZATION1 (VRN1) and VRN3 in phylogenetically representative taxa under cold and control conditions. Our results demonstrate that vernalization responsive Pooideae species are widespread, suggesting that this trait evolved early in the lineage and that at least part of the vernalization gene network is conserved throughout the subfamily. These results are consistent with the hypothesis that the evolution of vernalization responsiveness was important for the initial transition of Pooideae out of the tropics and into the temperate zone.
authors.affiliation: Department of Plant Biology, University of Vermont, Burlington, Vermont 05405 (M.M., J.C.P.); andDepartment of Plant Sciences, Norwegian University of Life Sciences, 1430 Ås, Norway (M.S., T.M., S.F.).
authors.forename: Meghan
authors.initials: M
authors.lastname: McKeown
authors.affiliation: Department of Plant Biology, University of Vermont, Burlington, Vermont 05405 (M.M., J.C.P.); andDepartment of Plant Sciences, Norwegian University of Life Sciences, 1430 Ås, Norway (M.S., T.M., S.F.).
authors.forename: Marian
authors.identifier: 0000-0001-7579-3832
authors.initials: M
authors.lastname: Schubert
authors.affiliation: Department of Plant Biology, University of Vermont, Burlington, Vermont 05405 (M.M., J.C.P.); andDepartment of Plant Sciences, Norwegian University of Life Sciences, 1430 Ås, Norway (M.S., T.M., S.F.).
authors.forename: Thomas
authors.identifier: 0000-0002-1960-9508
authors.initials: T
authors.lastname: Marcussen
authors.affiliation: Department of Plant Biology, University of Vermont, Burlington, Vermont 05405 (M.M., J.C.P.); andDepartment of Plant Sciences, Norwegian University of Life Sciences, 1430 Ås, Norway (M.S., T.M., S.F.).
authors.forename: Siri
authors.initials: S
authors.lastname: Fjellheim
authors.affiliation: Department of Plant Biology, University of Vermont, Burlington, Vermont 05405 (M.M., J.C.P.); andDepartment of Plant Sciences, Norwegian University of Life Sciences, 1430 Ås, Norway (M.S., T.M., S.F.) jill.preston@uvm.edu.
authors.forename: Jill C
authors.identifier: 0000-0002-9211-5061
authors.initials: JC
authors.lastname: Preston
mesh_terms: D018554:Avena / Q000235:genetics / Q000254:growth & development; D001499:Bayes Theorem; D003080:Cold Temperature; D019143:Evolution, Molecular; D035264:Flowers / Q000235:genetics* / Q000254:growth & development; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D001467:Hordeum / Q000235:genetics / Q000254:growth & development; D018519:Meristem / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D010802:Phylogeny; D010940:Plant Proteins / Q000145:classification / Q000235:genetics*; D018520:Plant Shoots / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D006109:Poaceae / Q000145:classification / Q000235:genetics* / Q000254:growth & development; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014908:Triticum / Q000235:genetics / Q000254:growth & development
chemical_list: D010940:Plant Proteins