title: Timing of rapid diversification and convergent origins of active pollination within Agavoideae (Asparagaceae).
abstract: OBJECTIVE
  Yucca species are ideal candidates for the study of coevolution due to the obligate mutualism they form with yucca moth pollinators (genera Tegeticula and Parategeticula). Yuccas are not the only species to exhibit a mutualism with yucca moths; the genus Hesperoyucca is pollinated by the California yucca moth (Tegeticula maculata). Relationships among yuccas, Hesperoyucca, and other members of subfamily Agavoideae are necessary to understand the evolution of this unique pollination syndrome. Here, we investigate evolutionary relationships of yuccas and closely related genera looking at the timing and origin of yucca moth pollination.
  
  
  METHODS
  In this study, we sequenced the chloroplast genomes of 20 species in the subfamily Agavoideae (Asparagaceae) and three confamilial outgroup taxa to resolve intergeneric phylogenetic relationships of Agavoideae. We estimated divergence times using protein-coding genes from 67 chloroplast genomes sampled across monocots to determine the timing of the yucca moth pollination origin.
  
  
  RESULTS
  We confidently resolved intergeneric relationships in Agavoideae, demonstrating the origin of the yucca-yucca moth mutualism on two distinct lineages that diverged 27 million years ago. Comparisons of Yucca and Hesperoyucca divergence time to those of yucca moths (Tegeticula and Parategeticula, Prodoxidae) indicate overlapping ages for the origin of pollinating behavior in the moths and pollination by yucca moths in the two plant lineages.
  
  
  CONCLUSIONS
  Whereas pollinating yucca moths have been shown to have a single origin within the Prodoxidae, there were independent acquisitions of active pollination on lineages leading to Yucca and Hesperoyucca within the Agavoideae.
authors: Donald Danforth Plant Science Center, 975 N. Warson Road, St. Louis, Missouri 63132 USA mrmckain@gmail.com.|Department of Plant Biology, University of Georgia, 120 Carlton Street, Athens, Georgia 30602 USA.
authors: Michael R
authors: MR
authors: McKain
authors: Department of Plant Biology, University of Georgia, 120 Carlton Street, Athens, Georgia 30602 USA.|Department of Ecology, Evolution, and Organismal Biology, Kennesaw State University, 1000 Chastain Road, Kennesaw, Georgia 30144 USA.
authors: Joel R
authors: JR
authors: McNeal
authors: Department of Biology, University of Nebraska at Omaha, 6001 Dodge Street, Omaha, Nebraska 68182 USA.
authors: P Roxanne
authors: PR
authors: Kellar
authors: Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Mexico City, Mexico.
authors: Luis E
authors: LE
authors: Eguiarte
authors: Division of Biological Sciences, University of Missouri, 311 Bond Life Sciences Center, 1201 East Rollins Street, Columbia, Missouri 65211 USA.
authors: J Chris
authors: JC
authors: Pires
authors: Department of Plant Biology, University of Georgia, 120 Carlton Street, Athens, Georgia 30602 USA.
authors: Jim
authors: J
authors: Leebens-Mack
mesh_terms: D000818:Animals; D000070357:Asparagaceae / Q000235:genetics / Q000502:physiology*; D044822:Biodiversity; D005075:Biological Evolution; D019143:Evolution, Molecular; D054628:Genome, Chloroplast / Q000235:genetics*; D059014:High-Throughput Nucleotide Sequencing; D009036:Moths / Q000502:physiology*; D010802:Phylogeny; D054817:Pollination; D017422:Sequence Analysis, DNA; D013559:Symbiosis; D027623:Yucca / Q000235:genetics / Q000502:physiology
keywords: Agavoideae; Hesperoyucca; Yucca; active pollination; chloroplast genome; convergent evolution; divergence time; obligate mutualism; yucca moth