title: Pleiotropy of FRIGIDA enhances the potential for multivariate adaptation.
abstract: An evolutionary response to selection requires genetic variation; however, even if it exists, then the genetic details of the variation can constrain adaptation. In the simplest case, unlinked loci and uncorrelated phenotypes respond directly to multivariate selection and permit unrestricted paths to adaptive peaks. By contrast, 'antagonistic' pleiotropic loci may constrain adaptation by affecting variation of many traits and limiting the direction of trait correlations to vectors that are not favoured by selection. However, certain pleiotropic configurations may improve the conditions for adaptive evolution. Here, we present evidence that the Arabidopsis thaliana gene FRI (FRIGIDA) exhibits 'adaptive' pleiotropy, producing trait correlations along an axis that results in two adaptive strategies. Derived, low expression FRI alleles confer a 'drought escape' strategy owing to fast growth, low water use efficiency and early flowering. By contrast, a dehydration avoidance strategy is conferred by the ancestral phenotype of late flowering, slow growth and efficient water use during photosynthesis. The dehydration avoidant phenotype was recovered when genotypes with null FRI alleles were transformed with functional alleles. Our findings indicate that the well-documented effects of FRI on phenology result from differences in physiology, not only a simple developmental switch.
authors.affiliation: Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO, USA.
authors.forename: John T
authors.initials: JT
authors.lastname: Lovell
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Juenger
authors.forename: Scott D
authors.initials: SD
authors.lastname: Michaels
authors.forename: Jesse R
authors.initials: JR
authors.lastname: Lasky
authors.forename: Alexander
authors.initials: A
authors.lastname: Platt
authors.forename: James H
authors.initials: JH
authors.lastname: Richards
authors.forename: Xuhong
authors.initials: X
authors.lastname: Yu
authors.forename: Hsien M
authors.initials: HM
authors.lastname: Easlon
authors.forename: Saunak
authors.initials: S
authors.lastname: Sen
authors.forename: John K
authors.initials: JK
authors.lastname: McKay
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics*; D000483:Alleles; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D005075:Biological Evolution; D055864:Droughts; D035264:Flowers / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D058685:Genetic Pleiotropy; D014644:Genetic Variation; D005838:Genotype; D010641:Phenotype
chemical_list: D029681:Arabidopsis Proteins
keywords: Arabidopsis thaliana; drought; flowering time; water use efficiency