Genomic Resources for Leersia perrieri: An Outgroup Species For The Genus Oryza

The Leersia genus is sister to the genus Oryza, which contains the world’s most important food crop – rice (O. sativa). The Leersia contains 17 species, nine of which are of African origin. Because of Leersia’s phylogenetic position to Oryza, it is the closest outgroup that can be used to help unravel the Oryza evolutionary history. Our ultimate goal is to generate a reference genome sequencefor Leersia perrieri. Toward accomplishment this goal we constructed a high quality BAC library and generated a heavily manually edited BAC-based physical map of the L. perrieri genome, an African diploid species with 12 chromosomes and a genome size of 323 Mb, and analyzed a BAC-end sequence data set for repeat and gene content. One third of the genome was found to consist of repeats, detected both with a de novo approach and by homology with existing TE libraries. The high amount of newly-discovered repeats (35% of the total) indicates that the L. perrieri genome is evolving rapidly relative to the Oryza genus. Six new families of retroelements were detected and their complete sequences could be reconstructed. Tandem repeats and simple sequence repeats showed to be peculiar in sequence and abundance. The gene content was estimated to be about 31,000. A detailed characterization of these public resources and data will be presented along with a plan to generate a complete genome sequence of the L. perrieri that is anchored to the physical map.