DOI:10.1111/pbi.13205

Linkai Huang , Guangyan Feng , Haidong Yan, Zhongren Zhang , Bradley Shaun Bushman , Jianping Wang , Aureliano Bombarely , Mingzhou Li , Zhongfu Yang , Gang Nie , Wengang Xie , Lei Xu , Peilin Chen , Xinxin Zhao, Wenkai Jiang , Xinquan Zhang

发表期刊：Plant Biotechnology Journal

链接：https://pubmed.ncbi.nlm.nih.gov/31276273/

Abstract：

Orchardgrass (Dactylis glomerataL.) is an important forage grass for cultivating livestock worldwide. Here, we report an ~1.84-Gb chromosome-scale diploid genome assembly of orchardgrass, with a contig N50 of 0.93 Mb, a scaffold N50 of 6.08 Mb and a super-scaffold N50 of 252.52 Mb, which is the first chromosome-scale assembled genome of a cool-season forage grass. The genome includes 40 088 protein-coding genes, and 69% of the assembled sequences are transposable elements, with long terminal repeats (LTRs) being the most abundant. The LTRretrotransposons may have been activated and expanded in the grass genome in response to environmental changes during the Pleistocene between 0 and 1 million years ago. Phylogenetic analysis reveals that orchardgrass diverged after rice but before three Triticeae species, and evolutionarily conserved chromosomes were detected by analysing ancient chromosome rearrangements in these grass species. We also resequenced the whole genome of 76 orchardgrass accessions and found that germplasm from Northern Europe and East Asia clustered together, likely due to the exchange of plants along the 'Silk Road' or other ancient trade routes connecting the East and West. Last, a combined transcriptome, quantitative genetic and bulk segregant analysis provided insights into the genetic network regulating flowering time in orchardgrass and revealed four main candidate genes controlling this trait. This chromosome-scale genome and the online database of orchardgrass developed here will facilitate the discovery of genes controlling agronomically important traits, stimulate genetic improvement of and functional genetic research on orchardgrass and provide comparative genetic resources for other forage grasses.