Abstract Detail

Comparative Genomics/Transcriptomics

Schafran, Peter [1], Xu, Xia [1], Robison, Tanner [2], Hauser, Duncan [1], Gunadi, Andika [1], Wickell, David [3], Villarreal Aguilar, Juan Carlos [4], Li, Fay-Wei [5].

Twelve high-quality genomes highlight genomic diversity across the hornworts.

In order to gain a holistic view of the critical transitions in land plant evolution, it is necessary to examine a phylodiverse set of genomes. The extant Anthocerotophyta (hornworts) represents an approximately 400 million-year-old lineage sister to Setaphyta (mosses + liverworts). While four hornwort genomes have been published, they all belong to closely related Anthoceros species. Furthermore, many of the traits characteristic of hornworts—such as the presence of both cyanobacterial and mycorrhizal symbioses, a pyrenoid-based carbon-concentrating mechanism (CCM), and stomata on the sporophyte—are not stable across the hornwort phylogeny and had experienced multiple losses, gains, and/or significant modifications. The current narrow sampling of hornwort genomes therefore could not adequately represent the whole lineage, and is limiting our ability to understand not only the evolution of land plants in general, but also the unique biology of hornworts. Here we present eight preliminary genome assemblies and annotations from every hornwort family and analysis including the four previously published Anthoceros genomes. Assembled genome sizes varied from 109 to 176 Mb, with N50 values from 1.3 to 18 Mb, representing nearly chromosomal-level assembly in some cases. We predicted 20,000 to 26,000 genes per genome using a combination of RNA-seq data and protein evidence. With this new genomic and phylogenetic framework, we aim to better characterize hornworts’ dynamic evolution of CCM, symbioses, and stomata. We will further revisit our current understanding of early land plant evolution in light of these genomic resources.

1 - Boyce Thompson Institute, 533 Tower Rd., Ithaca, NY, 14853, US
2 - Cornell University, Plant Biology, 533 Tower Road, Ithaca, NY, 14853, United States
3 - Cornell University, Plant Biology, Ithaca, NY, 14853, USA
4 - Laval University, Canada
5 - Boyce Thompson Institute, 533 Tower Rd, Ithaca, NY, 14853, United States

Keywords:
hornworts
bryophytes
Genomes
Nanopore.

Presentation Type: Oral Paper
Session: CG3, Functional & Comparative Genetics/Genomics III
Location: Virtual/Virtual
Date: Friday, July 31st, 2020
Time: 3:30 PM
Number: CG3003
Abstract ID:722
Candidate for Awards:Margaret Menzel Award