Location: Forage and Range ResearchTitle: Genome size, redundancy, and organization of Kentucky bluegrass determined by de novo genome assembly
Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/16/2021
Publication Date: N/A
Interpretive Summary: Kentucky bluegrass is and important turfgrass used in a variety of settings. It has a complex genome and mating system, which provides challenges to breeding and improving Kentucky bluegrass to overcome drought, heat, and salinity. We gained a better understanding of the organization and complexity of the genome and developed tools for breeding by sequencing the genome and identifying genes sequences, gene copy numbers, and repetitive sequences throughout the genome of Kentucky bluegrass.
Technical Abstract: Kentucky Bluegrass (Poa pratensis L.) is an important cool-season, perennial turfgrass used in sports fields, golf course roughs and fairways, residential lawns, roadsides, and public parks. Breeding and improvement of Kentucky bluegrass is challenging due to its range of ploidy levels (2n = 8-16, x = 7), mixed auto/allopolyploidy, aneuploidy, and facultative apomictic plants and populations. A chromosome-level genome sequence can help understand the genome organization of this species and provide tools to breed for abiotic stress (drought, heat, and salt tolerance) and improved turf quality. De novo assemblies were developed using PacBio CLR and CCS reads from a polyhaploid with multiple assemblers. The most contiguous and complete assemblies were scaffolded using proximity ligation to obtain an assembly with 572 contigs of 3.9 Gb in length with an N50 of 116 Mb and 98% complete BUSCOs. Whole RNA was extracted from several tissues and sequenced using PacBio isoseq to provide full-length transcripts and isoforms which were used to provide gene annotations. To better understand the organization and complexity of the genome, we analyzed transposable elements, gene copy numbers, and redundancy and structure of vernalization genes in the genome assembly.