Low-copy nuclear sequence data confirm complex patterns of farina evolution in notholaenid ferns (Pteridaceae).
Date
2019-09
Authors
Journal Title
Journal ISSN
Volume Title
Repository Usage Stats
views
downloads
Citation Stats
Abstract
Notholaenids are an unusual group of ferns that have adapted to, and diversified within, the deserts of Mexico and the southwestern United States. With approximately 40 species, this group is noted for being desiccation-tolerant and having "farina"-powdery exudates of lipophilic flavonoid aglycones-that occur on both the gametophytic and sporophytic phases of their life cycle. The most recent circumscription of notholaenids based on plastid markers surprisingly suggests that several morphological characters, including the expression of farina, are homoplasious. In a striking case of convergence, Notholaena standleyi appears to be distantly related to core Notholaena, with several taxa not before associated with Notholaena nested between them. Such conflicts can be due to morphological homoplasy resulting from adaptive convergence or, alternatively, the plastid phylogeny itself might be misleading, diverging from the true species tree due to incomplete lineage sorting, hybridization, or other factors. In this study, we present a species phylogeny for notholaenid ferns, using four low-copy nuclear loci and concatenated data from three plastid loci. A total of 61 individuals (49 notholaenids and 12 outgroup taxa) were sampled, including 31 out of 37 recognized notholaenid species. The homeologous/allelic nuclear sequences were retrieved using PacBio sequencing and the PURC bioinformatics pipeline. Each dataset was first analyzed individually using maximum likelihood and Bayesian inference, and the species phylogeny was inferred using *BEAST. Although we observed several incongruences between the nuclear and plastid phylogenies, our principal results are broadly congruent with previous inferences based on plastid data. By mapping the presence of farina and their biochemical constitutions on our consensus phylogenetic tree, we confirmed that the characters are indeed homoplastic and have complex evolutionary histories. Hybridization among recognized species of the notholaenid clade appears to be relatively rare compared to that observed in other well-studied fern genera.
Type
Department
Description
Provenance
Citation
Permalink
Published Version (Please cite this version)
Publication Info
Kao, T, KM Pryer, FD Freund, MD Windham and CJ Rothfels (2019). Low-copy nuclear sequence data confirm complex patterns of farina evolution in notholaenid ferns (Pteridaceae). Molecular phylogenetics and evolution, 138. pp. 139–155. 10.1016/j.ympev.2019.05.016 Retrieved from https://hdl.handle.net/10161/21745.
This is constructed from limited available data and may be imprecise. To cite this article, please review & use the official citation provided by the journal.
Collections
Scholars@Duke
![Pryer](https://scholars.duke.edu/profile-images/thumbnail200/0079353.jpg)
Kathleen M. Pryer
Unless otherwise indicated, scholarly articles published by Duke faculty members are made available here with a CC-BY-NC (Creative Commons Attribution Non-Commercial) license, as enabled by the Duke Open Access Policy. If you wish to use the materials in ways not already permitted under CC-BY-NC, please consult the copyright owner. Other materials are made available here through the author’s grant of a non-exclusive license to make their work openly accessible.