Abstract Detail

Comparative Genomics/Transcriptomics

Deb, Sontosh [1], Carey, Sarah [2], Harkess, Alex [3], Lewis, Michelle [4], McKain, Michael [5].

A highly contiguous Vossia cuspidata genome provides insights into the diploidization of maize.

Polyploidy is prevalent in the tribe Andropogoneae (Panicoideae; Poaceae) with over 30 identified, independent events. Andropogoneae includes many ecologically and economically important species like maize, sorghum, and sugarcane. Maize (Zea mays L.) is a suspected ancient allopolyploid having originated ~5-15 mya after the merging and doubling of two unknown ancestral genomes and prior to the diversification of the Zea and Tripsacum genera. Despite sharing the same polyploid event, Zea (n=10) and Tripsacum (n=18) experienced distinct chromosomal rearrangements demonstrating the unique trajectory that divergent lineages can take during the diploidization process. Vossia cuspidata (Roxb.) Griff. (hippo grass) and other members of the subtribe Rhytachninae have been suggested to be close relatives of one of the diploid progenitors to the shared polyploid event of maize and Tripsacum. Here, we present a highly contiguous genome assembly of Vossia cuspidata based on PacBio HiFi sequencing and scaffolded using Hi-C data. Using this resource, we conduct comparative phylogenomic analyses with the maize, sorghum, and Setaria italica (L.) P. Beauvois genomes to test the hypothesis that Vossia is a relative of a maize/Tripsacum diploid progenitor. We also investigated the signal of homoeologous exchanges with replacement between maize subgenomes estimating the impact of homoeologous exchange on the diploidization process in maize. Evidence from these analyses suggests that Vossia is more closely related to one of the maize diploid progenitors and that homoeologous exchanges potentially obscure the ancestry of maize subgenomes. Future work will include comparisons of homoeologous exchange across other sequenced maize lines to further explore variability of homoeologous exchange over time.

1 - The University of Alabama, 405 Mary Harmon Bryant Hall, Tuscaloosa, AL, 35487, United States
2 - Auburn University and HudsonAlpha Institute for Biotechnology, 107 Comer Hall, Auburn, AL, 36849,, USA
3 - Auburn University and HudsonAlpha Institute for Biotechnology, 601 Genome Way, Huntsville, AL, 35806, United States
4 - The University of Alabama, Mary Harmon Bryant Hall, Tuscaloosa, AL, 35487, United States
5 - The University of Alabama, 411 Mary Harmon Bryant Hall, Tuscaloosa, AL, 35487, United States

Keywords:
polyploidy
Homoeologous exchange
Subgenome
phylogenomics.

Presentation Type: Poster
Session: P1, Comparative Genomics/Transcriptomics Posters
Location: Virtual/Virtual
Date: Monday, July 19th, 2021
Time: 5:00 PM(EDT)
Number: P1GT013
Abstract ID:994
Candidate for Awards:None