Marta Brozynska, Dario Copetti, Agnelo Furtado, Rod A. Wing, Darren Crayn, Glen Fox, Ryuji Ishikawa, Robert J. Henry
Volume 15, Issue 6 June 2017 Pages 765–774
Keywords assembly; molecular clock; sequencing; Oryza ; phylogeny; wild rice Publication History Issue online: 10 May 2017 Version of record online: 23 January 2017 Accepted manuscript online: 27 November 2016 Manuscript Accepted: 23 November 2016 Manuscript Revised: 10 October 2016 Manuscript Received: 14 July 2016
Summary
The related A genome species of the Oryza genus are the effective gene pool for rice. Here, we report draft genomes for two Australian wild A genome taxa: O. rufipogon-like population, referred to as Taxon A, and O. meridionalis-like population, referred to as Taxon B. These two taxa were sequenced and assembled by integration of short- and long-read next-generation sequencing (NGS) data to create a genomic platform for a wider rice gene pool. Here, we report that, despite the distinct chloroplast genome, the nuclear genome of the Australian Taxon A has a sequence that is much closer to that of domesticated rice (O. sativa) than to the other Australian wild populations. Analysis of 4643 genes in the A genome clade showed that the Australian annual, O. meridionalis, and related perennial taxa have the most divergent (around 3 million years) genome sequences relative to domesticated rice. A test for admixture showed possible introgression into the Australian Taxon A (diverged around 1.6 million years ago) especially from the wild indica/O. nivara clade in Asia. These results demonstrate that northern Australia may be the centre of diversity of the A genome Oryza and suggest the possibility that this might also be the centre of origin of this group and represent an important resource for rice improvement.
http://onlinelibrary.wiley.com/doi/10.1111/pbi.12674/abstract
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