Complete chloroplast genomes of Saccharum spontaneum, Saccharum officinarum and Miscanthus floridulus (Panicoideae: Andropogoneae) reveal the plastid view on sugarcane origins
Complete chloroplast genomes of Saccharum spontaneum, Saccharum officinarum and Miscanthus floridulus (Panicoideae: Andropogoneae) reveal the plastid view on sugarcane origins
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DOI：
10.1080/14772000.2016.1197336
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发表时间：
2016-01-01
影响因子：
1.9
通讯作者：
Joshi, Shailesh Vinay
中科院分区：
文献类型：
--
作者：
Evans, Dyfed Lloyd;Joshi, Shailesh Vinay
甘蔗（甘蔗杂交品种）是世界十大粮食作物之一，每年提供全球60-70%的糖产量。尽管它的经济重要性，一直没有大规模的系统学研究属甘蔗和现有的模式起源仍然在很大程度上没有受到挑战，近50年。我们首次组装了五节芒（Miscanthus floridulus）（本属的首次报道）、密穗苔（Spontaneum）和药用苔（Spontaneum officinarum）的完整质体基因组，从而阐明了密穗苔（Spontaneum s.s.）物种我们证明，S.S.分为4个种，其中S. spontaneum约在150万年前从该属的其余部分中分化出来;在75万年前开始分化两个独立的谱系，一个通向S。officinarum和另一个导致现代杂交品种从S. 64万年前的粗壮木这些发现推翻了以前所有关于甘蔗起源的假设，表明甘蔗的祖先不可能是由人类活动引起的。所有现代品种共享一个共同的波利尼西亚起源，而旧世界的甘蔗，S。barberi和S. sinense，聚为一个明显的S. officinarum谱系这使得现代栽培种成为一个独特的种属，我们正式提出的名称为cultum cultum的祖先的所有血统目前被归类为cultum杂交品种。
Sugarcane (Saccharum hybrid cultivar) ranks among the world's top 10 food crops and annually provides 60-70% of the sugar produced worldwide. Despite its economic importance there has been no large-scale systematics study of genus Saccharum and the existing model of sugarcane origins has remained largely unchallenged for almost 50 years. For the first time, we have assembled the complete plastid genomes of Miscanthus floridulus (first report for this genus), Saccharum spontaneum and Saccharum officinarum allowing us to elucidate the phylogenetic origins of Saccharum s.s. species. We demonstrate that Saccharum s.s. is divided into four species, with S. spontaneum diverging from the remainder of the genus about 1.5 million years ago and S. robustum diverging 750,000 years ago. Two separate lineages, one leading to S. officinarum and the other leading to modern hybrid cultivars diverged from S. robustum 640,000 years ago. These findings overturn all previous hypotheses on sugarcane origins, demonstrating that sugarcane's antecedents could not have arisen by human action. All modern cultivars share a common Polynesian origin, whereas Old World canes, S. barberi and S. sinense, cluster as a distinct S. officinarum lineage. This makes modern cultivars a distinct species of genus Saccharum, and we formally propose the name Saccharum cultum for the ancestor of all lineages currently classified as Saccharum hybrid cultivars.