Evolution on the backbone Apocynaceae phylogenomics and new perspectives on growth forms, flowers, and fruits

• Published in: American journal of botany Vol. 105; no. 3; pp. 495 - 513
• Main Authors: Fishbein, Mark, Livshultz, Tatyana, Straub, Shannon C. K., Simões, André O., Boutte, Julien, McDonnell, Angela, Foote, Abbey
• Format: Journal Article
• Language: English
• Published: United States John Wiley and Sons, Inc 01.03.2018; Botanical Society of America, Inc
• Subjects: ancestral state reconstruction; Apocynaceae; Apocynaceae - genetics; Apocynaceae - growth & development; Biological Evolution; corolla shape; corona; Evolution; Evolution, Molecular; Evolutionary biology; Flowers; Flowers & plants; Fruit; fruit type; Fruits; Genetic Loci; Genome, Plastid; Genomics - methods; growth habit; INVITED SPECIAL ARTICLE: For the Special Issue: Using and Navigating the Plant Tree of Life; Likelihood Functions; maximum likelihood; model of character evolution; Models, Genetic; Molecular chains; Phenotype; Phylogenetics; Phylogeny; Plant Stems; plastid and plastome sequences; Plastids; Plastomes; stochastic mapping; Taxa; vines; Wood; growth habit; plastid and plastome sequences; corolla shape; maximum likelihood; stochastic mapping; model of character evolution; fruit type; vines; ancestral state reconstruction; corona
• ISSN: 0002-9122; 1537-2197
• DOI: 10.1002/ajb2.1067

Premise of the Study We provide the largest phylogenetic analyses to date of Apocynaceae in terms of taxa and molecular data as a framework for analyzing the evolution of vegetative and reproductive traits. Methods We produced maximum‐likelihood phylogenies of Apocynaceae using 21 plastid loci sampled from 1045 species (nearly 25% of the family) and complete plastomes from 73 species. We reconstructed ancestral states and used model comparisons in a likelihood framework to analyze character evolution across Apocynaceae. Key Results We obtained a well‐supported phylogeny of Apocynaceae, resolving poorly understood tribal and subtribal relationships (e.g., among Amsonieae and Hunterieae, within Asclepiadeae), rejecting monophyly of Melodineae and Odontadenieae, and placing previously unsampled and enigmatic taxa (e.g., Pycnobotrya). We provide new insights into the evolution of Apocynaceae, including frequent shifts between herbaceousness and woodiness, reversibility of twining, integrated evolution of the corolla and gynostegium, and ancestral baccate fruits. Conclusions Increased sampling and selection of best‐fitting models of evolution provide more resolved and robust estimates of phylogeny and character evolution than obtained in previous studies. Evolutionary inferences are sensitive to choice of phylogenetic frameworks and models.