De novo Genome Sequencing of Perennial Ryegrass (Lolium perenne)

Lolium perenne (perennial ryegrass) is an outbreeding diploid species with an estimated genome size of 2,695 Mbp. It is the principal forage species used in temperate agriculture and therefore a prime candidate for genome sequencing. A sequenced genome will both enhance efforts to understand the genetic control of important traits, and accelerate the application of molecular breeding strategies to forage grasses. Sequencing efforts have focused on the IBERS inbred genotype p226/135/16, for which a number of resources have already been established. These include two BAC libraries generated from HindIII and BstY1 restriction enzymes, BAC end sequences, and transcriptome sequence data. Using Illumina GAIIx, Illumina HiSeq 2000, and Roche 454 we have sequenced a range of libraries for de novo assembly, including 200 bp and 600 bp insert paired-end libraries. We have also generated mate pair libraries with insert sizes of 3 Kb, 5 Kb and 10 Kb to aid scaffolding of contigs. These data have been used to generate a preliminary draft assembly of the perennial ryegrass genome.