Abstract Detail



Systematics

Lu, Jin-Mei [1], Du, Xin-Yu [1], Wen, Jun [2], Zhang, Libing [3], Li, De-Zhu [1].

Deep relationships and early divergences of the large fern lineage Polypodiales: Insights from plastid phylogenomics.

A series of molecular phylogenetic studies in recent years have reconstructed the evolutionary framework of ferns. However, the relationships among some families are still not well resolved. Polypodiales represents about 82% of the species diversity of ferns, and the relationships among the basal groups of Polypodiales remain unresolved or poorly supported, with the relationships of Pteridaceae, Dennstaedtiaceae and eupolypods still being controversial. Also, the phylogenetic positions of Saccolomaceae and some families in eupolypods are not well resolved. The primary objective of this study is to explore the application of plastid phylogenomics in resolving difficult backbone relationships of Polypodiales. We newly sequenced 166 plastomes representing 101 genera of 27 families of Polypodiales and two outgroups, and reconstructed the deep relationships of Polypodiales based on 214 samples (48 from GenBank) representing all 28 families in Polypodiales. The divergence times of the major clades in Polypodiales were estimated based on a reduced plastome dataset (151 taxa) and 13 fossil calibrations. The phylogenomic data resulted in a phylogeny of Polypodiales with nearly all deep nodes supported by 100 MLBS values and 1.0 BIPP values. All the 28 families were strongly supported as monophyletic groups as long as more than one accession was included. The vast majority of our results via detailed filtering scheme supported that the aggregate of Saccoloma-(Cystodium-(Lonchitis-Lindsiaceae)) was sister to the aggregate of ((Dennstaedtiaceae-Pteridaceae)- Eupolypods) in Polypodiales. The present study well resolved the relationships among all eleven families in Eupolypod II, which was resolved into four strongly supported subclades: the Cystopteridaceae subclade, the Thelypteridaceae subclade, the WOBA subclade, and the RHADD subclade. Eupolypods I also were resolved into four strongly supported subclades: the Didymochlaenaceae subclade, the Dryopteridaceae subclade, the Hypodematiaceae subclade, and the DANLOPPT. The stem and crown ages of Polypodiales were estimated at the Permian period and the Triassic period, respectively. The stem ages of the six suborders were estimated at 132.85–195.15 Ma, and the five suborders (except for suborder Saccolomatineae) diverged at 105.65–169.63 Ma. The early diversification of most families and subfamilies mainly took place at K/T-PETM period except for a few small groups. Plastid phylogenomics offers important insights into deep phylogenetic relationships and the diversification history of Polypodiales. The phylogenetic backbone and time estimates provide an important evolutionary framework for future comparative studies on Polypodiales.


1 - Kunming Institute Of Botany, Chinese Academy Of Sciences, 132# Lanhei Road, Heilongtan, Kunming, Yunnan, 650201, China
2 - Botany, MRC-166 National Museum Of Natural History, 10th St. & Constitution Ave., NW, Mrc 166, Washington/DC, 20013, United States
3 - Missouri Botanical Garden, Science & Conservation, P.O. Box 299, St. Louis, MO, 63166, United States
4 - Kunming Institute Of Botany, Chinese Academy Of Sciences, 132# Lanhei Road, Heilongtan, Kunming, Yunnan, 650201, China

Keywords:
Polypodiales
plastid phylogenomics
early polypod
divergence.

Presentation Type: Oral Paper
Number:
Abstract ID:625
Candidate for Awards:None


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