title: Evolution of oil-producing trichomes in Sisyrinchium (Iridaceae): insights from the first comprehensive phylogenetic analysis of the genus.
abstract: OBJECTIVE
  Sisyrinchium (Iridaceae: Iridoideae: Sisyrinchieae) is one of the largest, most widespread and most taxonomically complex genera in Iridaceae, with all species except one native to the American continent. Phylogenetic relationships within the genus were investigated and the evolution of oil-producing structures related to specialized oil-bee pollination examined.
  
  
  METHODS
  Phylogenetic analyses based on eight molecular markers obtained from 101 Sisyrinchium accessions representing 85 species were conducted in the first extensive phylogenetic analysis of the genus. Total evidence analyses confirmed the monophyly of the genus and retrieved nine major clades weakly connected to the subdivisions previously recognized. The resulting phylogenetic hypothesis was used to reconstruct biogeographical patterns, and to trace the evolutionary origin of glandular trichomes present in the flowers of several species.
  
  
  CONCLUSIONS
  Glandular trichomes evolved three times independently in the genus. In two cases, these glandular trichomes are oil-secreting, suggesting that the corresponding flowers might be pollinated by oil-bees. Biogeographical patterns indicate expansions from Central America and the northern Andes to the subandean ranges between Chile and Argentina and to the extended area of the Paraná river basin. The distribution of oil-flower species across the phylogenetic trees suggests that oil-producing trichomes may have played a key role in the diversification of the genus, a hypothesis that requires future testing.
authors.affiliation: Laboratoire Ecologie Systématique et Evolution, Université Paris-Sud, Orsay, France. olivier.chauveau@u-psud.fr
authors.forename: Olivier
authors.initials: O
authors.lastname: Chauveau
authors.forename: Lilian
authors.initials: L
authors.lastname: Eggers
authors.forename: Christian
authors.initials: C
authors.lastname: Raquin
authors.forename: Adriano
authors.initials: A
authors.lastname: Silvério
authors.forename: Spencer
authors.initials: S
authors.lastname: Brown
authors.forename: Arnaud
authors.initials: A
authors.lastname: Couloux
authors.forename: Corine
authors.initials: C
authors.lastname: Cruaud
authors.forename: Eliane
authors.initials: E
authors.lastname: Kaltchuk-Santos
authors.forename: Roxana
authors.initials: R
authors.lastname: Yockteng
authors.forename: Tatiana T
authors.initials: TT
authors.lastname: Souza-Chies
authors.forename: Sophie
authors.initials: S
authors.lastname: Nadot
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D001516:Bees / Q000502:physiology*; D005075:Biological Evolution; D018744:DNA, Plant / Q000737:chemistry / Q000235:genetics; D035264:Flowers / Q000378:metabolism*; D017343:Genes, Plant / Q000235:genetics; D005843:Geography; D027621:Iridaceae / Q000145:classification* / Q000235:genetics* / Q000378:metabolism; D016013:Likelihood Functions; D008928:Mitochondria / Q000235:genetics; D009656:North America; D010802:Phylogeny; D010938:Plant Oils / Q000378:metabolism*; D018087:Plastids / Q000235:genetics; D054817:Pollination; D016415:Sequence Alignment; D013020:South America
chemical_list: D018744:DNA, Plant; D010938:Plant Oils