The Litsea genome and the evolution of the laurel family

First author: Yi-Cun Chen; Affiliations: State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry (林科院林木遗传育种国家重点实验室): Beijing, China

Corresponding author: Yang-Dong Wang

The laurel family within the Magnoliids has attracted attentions owing to its scents, variable inflorescences, and controversial phylogenetic position. Here, we present a chromosome-level assembly of the Litsea cubeba genome, together with low-coverage genomic and transcriptomic data for many other Lauraceae. Phylogenomic analyses show phylogenetic discordance at the position of Magnoliids, suggesting incomplete lineage sorting during the divergence of monocots, eudicots, and Magnoliids. An ancient whole-genome duplication (WGD) event occurred just before the divergence of Laurales and Magnoliales; subsequently, independent WGDs occurred almost simultaneously in the three Lauralean lineages. The phylogenetic relationships within Lauraceae correspond to the divergence of inflorescences, as evidenced by the phylogeny of FUWA, a conserved gene involved in determining panicle architecture in Lauraceae. Monoterpene synthases responsible for production of specific volatile compounds in Lauraceae are functionally verified. Our work sheds light on the evolution of the Lauraceae, the genetic basis for floral evolution and specific scents.

木兰类植物中的樟科（laurel family）由于其香味、多变的花序以及争议性的系统发育地位吸引了人们的关注。本文中，作者报道了山苍子（Litsea cubeba）染色体级别的基因组，以及樟科其它植物物种的低深度基因组和转录组数据。系统基因组学分析显示木兰类植物的系统发育地位存在不一致性，说明在单、双子叶以及木兰类的分化时存在不完全谱系分选（incomplete lineage sorting）。作者发现在木栏目和樟目分化前不久发生过一次古老的全基因组复制事件；随后，在三个樟科支系中几乎同时独立发生了全基因组复制事件。樟科内的系统发育关系与花序的分化一致，即与一个在樟科植物物种中参与圆椎花序（panicle）结构决定的基因FUWA的系统发育一致。作者鉴定并功能验证了作用于樟科特异挥发性化合物生产的单萜合酶。本文的研究揭示了樟科的演化，并为樟科花和特定香气的演化提供了遗传基础。

通讯：汪阳东

个人简介：1992-1996年，安徽师范大学，学士；1996-1999年，中国林业科学研究院，硕士；2003-2007年，中国林业科学研究院，博士。

研究方向：主要从事木本油料植物分子育种和化学工业原料树种遗传育种研究。

doi: https://doi.org/10.1038/s41467-020-15493-5

Journal: Nature Communications

Published date: April 03, 2020

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