Abstract Detail

Phylogenomics

Liu, Shih-Hui [1], Chiang, Tzen-Yuh [2], Huang, Chao-Li [2], Hsu, Tsai-Wen [3], Chang, Chia-Hao [4], Raven, Peter H. [5], Hoch, Peter C. [6], Barber, Janet C. [1].

Targeted capture of putative single copy genes using next generation sequencing yields new insights into polyploid evolution of Ludwigia section Macrocarpon (Onagraceae).

While polyploidization is considered a major evolutionary force in angiosperms, the origins, patterns, and impacts of polyploidization are still not fully understood. The primary goal of our study is to increase understanding of polyploid evolution and the role of polyploidy in speciation using section Macrocarpon (Ludwigia L., Onagraceae) as a model. This section contains two diploid species (L. bonariensis, L. lagunae) and one putative tetraploid species (L. neograndiflora), all of which have restricted distributions; a fourth polyploid species, L. octovalvis, is distributed worldwide. A phylogeny of genus Ludwigia based on discrete nuclear and chloroplast DNA sequences strongly supports the monophyly of section Macrocarpon but was unable to resolve relationships among species in the section. In this study, we developed a relatively rapid and inexpensive next generation sequencing workflow to capture putative single copy genes. We screened genome-wide scaffolds of L. palustris, identified putative single copy orthologous nuclear genes, and designed a set of primers to target these genes. Homoeologous alleles were identified and used in our phylogenetic analyses. Our preliminary results based on 32 genes in 16 samples from sect. Macrocarpon and one outgroup, L. palustris, suggest that all ingroups, except diploid L. octovalvis, exhibit heterozygotes in the studied genes. Hexaploid L. octovalvis likely arose from hybridization between tetraploid and diploid L. octovalvis. Moreover, L. lagunae is closely related to L. bonariensis, while L. bonariensis may have contributed to polyploid speciation in L. neograndiflora.

1 - Saint Louis University, Biology, 3507 Laclede Avenue, St. Louis, MO, 63103, USA
2 - National Cheng Kung University, Life Sciences, No.1, University Road, Tainan, 701, Taiwan
3 - Endemic Species Research Institute, No. 1, Ming-shen East Road,, Chichi Township, , Nantou County , 552, , Taiwan
4 - Academia Sinica, Biodiversity Research Center, 128 Academia Road Sec. 2, Taipei City , 115, Taiwan
5 - Missouri Botanical Garden, 2345 TOWER GROVE, St. Louis, MO, 63110, USA
6 - Missouri Botanical Garden, P.O. Box 299, , St. Louis, , MO, 63166-0299, USA

Keywords:
Ludwigia
Homoeologous
allopolyploidization.

Presentation Type: Poster
Session: P, Phylogenomics Posters
Location: Exhibit Hall/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 5:30 PM This poster will be presented at 6:15 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PPY004
Abstract ID:281
Candidate for Awards:Genetics Section Poster Award