The evolution study on Oryza rufipogon. dw by whole-genome sequencing

The species of Oryza rufipogon. dw was first discovered at Dongxiang, Jiangxi in 1978. It is recognized as abundant in genetic resources with the characteristics of cold and insect resistance. A total of 100.15 Gb raw data was obtained from seven pair-end libraries by Illumina Hiseq4000 platform. Subsequently, a draft assembly genome of O. rufipogon. dw was generated with a final size of 422.7 Mb with a contig N50 of 15 kb and a scaffold N50 of 296.2 bb. The assembly genome size was higher than the estimated genome size (413 Mb) based on k-mer analysis. The identified repeat sequences accounted for 40.09% of the entire genome, and 32,521 protein-coding genes with an average of 4.59 exons per gene was annotated in five databases. Phylogenetic analysis using 1460 single-copy gene, O. rufipogon. dw was close with O. rufipogon by Bayes method. The wild rice species of O. rufipogon. dw divergence was estimated at ∼0.3 million years ago (Mya) from O. rufipogon, and ∼0.6 Mya from the O. sativa. The draft genome of O. rufipogon. dw provided an essential resource for its origin and evolution study.