Abstract Detail

Systematics

Becklund, Ellie [1], Schenk, John [2].

Phylogenomics Reveal Species Relationships in Neptunia (Fabaceae).

Neptunia (Fabaceae) is a pantropical genus of twelve species, two of which are aquatic and have global distributions (N. oleracea and N. plena). The genus is characterized by unarmed prostrate or ascending stems, sensitive leaves, and heteromorphic inflorescences with distally perfect but proximally sterile or male flowers. The aquatic species form aerenchyma in their stems to float on slow moving rivers or pools. Previous taxonomic studies of Neptunia have described thirty taxa, and molecular studies that included two, four, or nine Neptunia species reconstructed a monophyletic genus from three chloroplast regions and nrDNA markers but were unable to resolve inter- and infraspecific relationships. Here, we use a target-capture approach with the Angiosperms-353 bait set to sequence hundreds of nuclear genes and the chloroplast genome to infer species relationships of six Neptunia species. DNA sequences were reference-guided assembled and gene trees were reconstructed with maximum likelihood. The reconstructed phylogeny identified continental clades of species across the genus and that the Australian clade was most closely related to the two globally distributed aquatic species. The two aquatic species were sister to each other, indicating a single transition to an aquatic habitat. Our phylogenetic results also shed light into the taxonomically labile N. pubescens; the N. pubescens complex formed a monophyletic group and preliminary infraspecific structure is supported by morphological and geographic evidence, however, additional sampling will be needed to assess infraspecific relationships. Currently, we are continuing to sequence the remaining species of Neptunia and additional global populations of N. oleracea and N. plena and South American populations of N. pubescens. Resolving the phylogeny of Neptunia will allow us to gain insight on the species of this pantropical genus and provide an evolutionary framework to ask questions about speciation, adaptation, and habitat transitions in terrestrial and aquatic plants.

1 - Ohio University, Environmental And Plant Biology Department, Porter Hall, Athens, OH, 45701, United States
2 - Ohio University, Department Of Environmental And Plant Biology, 22 Richland Ave., 401 Porter Hall, Athens, OH, 45701, United States

Keywords:
systematics
phylogenomics
Fabaceae
Angiosperms-353
chloroplast
target-capture
Hyb-Seq
Neptunia.

Presentation Type: Poster
Number: PSY003
Abstract ID:184
Candidate for Awards:None