title: Phylogenetics and diversification of morning glories (tribe Ipomoeeae, Convolvulaceae) based on whole plastome sequences.
abstract: OBJECTIVE
  Morning glories are an emerging model system, and resolving phylogenetic relationships is critical for understanding their evolution. Phylogenetic studies demonstrated that the largest morning glory genus, Ipomoea, is not monophyletic, and nine other genera are derived from within Ipomoea. Therefore, systematic research is focused on the monophyletic tribe Ipomoeeae (ca. 650-900 species). We used whole plastomes to infer relationships across Ipomoeeae.
  
  
  METHODS
  Whole plastomes were sequenced for 29 morning glory species, representing major lineages. Phylogenies were estimated using alignments of 82 plastid genes and whole plastomes. Divergence times were estimated using three fossil calibration points. Finally, evolution of root architecture, flower color, and ergot alkaloid presence was examined.
  
  
  RESULTS
  Phylogenies estimated from both data sets had nearly identical topologies. Phylogenetic results are generally consistent with prior phylogenetic hypotheses. Higher-level relationships with weak support in previous studies were recovered here with strong support. Molecular dating analysis suggests a late Eocene divergence time for the Ipomoeeae. The two clades within the tribe, Argyreiinae and Astripomoeinae, diversified at similar times. Reconstructed most recent common ancestor of the Ipomoeeae had blue flowers, an association with ergot-producing fungi, and either tuberous or fibrous roots.
  
  
  CONCLUSIONS
  Phylogenetic results provide confidence in relationships among Ipomoeeae lineages. Divergence time estimation results provide a temporal context for diversification of morning glories. Ancestral character reconstructions support previous findings that morning glory morphology is evolutionarily labile. Taken together, our study provides strong resolution of the morning glory phylogeny, which is broadly applicable to the evolution and ecology of these fascinating species.
authors.affiliation: Plant Biology Department, University of Georgia, Athens, Georgia 30602 USA.
authors.forename: Lauren A
authors.initials: LA
authors.lastname: Eserman
authors.forename: George P
authors.initials: GP
authors.lastname: Tiley
authors.forename: Robert L
authors.initials: RL
authors.lastname: Jarret
authors.forename: Jim H
authors.initials: JH
authors.lastname: Leebens-Mack
authors.forename: Richard E
authors.initials: RE
authors.lastname: Miller
mesh_terms: D001483:Base Sequence; D027722:Convolvulaceae / Q000235:genetics*; D014644:Genetic Variation; D054628:Genome, Chloroplast / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D018087:Plastids / Q000235:genetics*; D013997:Time Factors
keywords: Convolvulaceae; Ipomoea; Ipomoeeae; character evolution; chloroplast genomes; divergence time estimation; morning glories; phylogenetics; plastid sequences