Abstract Detail

Phylogenomics

Lewis, Michelle [1], Blakely, Sarah [1], McKain, Michael [2].

Phylogenomics of the genus Hosta: Disentangling the impact of an ancient polyploid event on phylogeny resolution.

The genus Hosta includes multiple ornamental species grown for their foliage and shade tolerance. The genus is composed of 23 accepted species, many of which have multiple recognized varieties. Additionally, numerous hybrids exist as part of an extensive horticulture trade. Hosta is a close relative of Agave, Yucca, and other members of the subfamily Agavoideae (Asparagaceae). Though all of its closest relatives are native to the Americas and many are adapted to deserts, hostas are native to Northeastern Asia, where they tend to grow in mesic and shaded environments. Studies have demonstrated that hostas have some drought tolerance, though the extent of this tolerance across species remains undocumented. Due to their phylogenetic placement as sister to a clade with multiple desert lineages, the evolution of drought tolerance in Hosta is of great interest for comparative studies to xerophytes. Understanding drought tolerance in Hosta, however, requires a well-resolved phylogeny. We used genome skimming to assemble complete chloroplast genomes for 33 accessions of hostas, representing 19 species, nine unresolved taxa, and five varieties. We combined these data with published Hosta chloroplast genomes and those from other members of Agavoideae to serve as outgroups. Using these data, we reconstructed the complete chloroplast phylogeny for much of the Hosta genus. In addition to whole chloroplast genomes, we used the Angiosperm353 target capture kit to look at nuclear loci across our taxa. Hosta shares a polyploid event with other members of the Agavoideae Bimodal Karyotype clade, leaving a number of paralogs present in the Hosta genome. We investigated the phylogenomic signal of different loci from the Angiosperm353 set and the impact that paralog retention had on our ability to resolve the Hosta phylogeny. We find that there is variation in paralog retention in the Angiosperm353 target capture set across taxa, and that about 50% of the target loci are obtainable from Hosta and other members of Agavoideae. We use the chloroplast and nuclear phylogenies to identify trends dispersal of Hosta as it moved from the Asian mainland to the Japanese archipelago. Finally, we look at Hosta in the larger context of Agavoideae and consider future directions to investigate desert adaptation using Hosta in comparative genomic studies.

1 - The University of Alabama, 500 Hackberry Lane, Box 870344, Mary Harmon Bryant Rm 411, Tuscaloosa, AL, 35487, United States
2 - University Of Alabama, 411 Mary Harmon Bryant Hall, Tuscaloosa, AL, 35487, United States

Keywords:
chloroplast
target capture
Angiosperm353
Hosta
Agavoideae
polyploidy.

Presentation Type: Oral Paper
Session: PHYL4, Phylogenomics IV
Location: Virtual/Virtual
Date: Friday, July 31st, 2020
Time: 4:00 PM
Number: PHYL4005
Abstract ID:831
Candidate for Awards:None