Plant Records: Don’t judge ryegrass by its looks

Name: Perennial ryegrass

Scientific name: Lolium perenne L.

Known for: Being a super yummy forage grass for grazing ruminants and liked as turf for sports people in temperate climates of the world

Record broken: Two genomes in parallel!

Ryegrass does not look spectacular at first sight. If you live in a temperate climate, you have probably walked over it already without giving it a second thought. The significance of rye grass lies in its commercial value. It provides highest quality forage as fodder for grazing ruminant animals like dairy cows, and especially meat lovers will appreciate superior meat quality produced through rain-fed grown forage. Also the sales of turf grasses, which include one of the perennial ryegrass types, comes second in commercial value after corn seed sales in the US

Ryegrass. Image Susanne Barth.

In 2016, not one but two genome drafts of perennial ryegrass were generated (Byrne et al. 2015; Velmurugan & Mollison et al. 2016), following rather similar strategies to provide much needed resources for genomic selection in this cross-pollinating plant species. Preparing these genome drafts was not a trivial task, since the ryegrass genome size is nearly more than half than that of the enormous barley genome (5100Mb: International Barley Genome Sequencing Consortium 2012). The estimated genome size was 2068 Mb, and 76% of the genome were estimated to be repetitive. Both draft genomes now cover 54% and 40% of the estimated genome size of perennial ryegrass, respectively.

Even though both teams were comparatively small, the advance in sequencing technologies and more efficient bioinformatics tools have enabled the non-thinkable from less than 10 years ago. Most gene coding areas are now well covered, and both genomes provide a wonderful resource to compare the genomes of the inbred lines of this species.

This also opens new opportunities to use both genomes for genetic improvement of this cross-pollinating forage and turf species. Velmurugan & Mollison et al. (2016) provide an anchorage of the genome to the highest genetic density available map of perennial ryegrass, and also provide an easy access to the genome with a genome browser.