2016年5月10日，玛卡（Maca, Lepidium meyenii）基因组论文在线发表于Molecular Plant 杂志上。玛卡是原产南美洲安第斯山脉（the Andes）的一种十字花科（Brassicaceae）独行菜属（Lepidium）的一种植物。叶子椭圆，根茎形似小圆萝卜，可食用，营养成分丰富。现在在云南可以广泛种植。

玛卡基因组包含64条染色体，二倍体，但相对于拟南芥是八倍体，也就是 2n = 8x = 64，意思是 monoploid number x = 8，haploid number n = 32。这篇论文报道的玛卡基因组组装 743 Mb，scaffold序列的 N50 为  2.4 Mb。注释了96417个编码蛋白基因，转座元素占比 47.65%。这篇论文最大的亮点在于鉴定了玛卡与拟南芥基因组分化后发生了两次基因组加倍，大约发生在 6700 万年前。

这篇论文的作者全部来自中国，共涉及13个科研单位，包括华中农业大学、吉林大学、云南农业大学、中科院昆明动物所、福建农林大学等。

论文标题：Genome of plant maca (Lepidium meyenii) illuminates genomic basis for high altitude adaptation in the central Andes

网址：http://dx.doi.org/10.1016/j.molp.2016.04.016

在线发表日期： 10 May 2016

论文摘要：

Maca (Lepidium meyenii Walp, 2n = 8x = 64) of Brassicaceae family is an Andean economic plant cultivated on the 4000-4500 meters central sierra in Peru. Considering the rapid uplift of central Andes occurred 5 to 10 million years ago (Mya), an evolutionary question arises on how plants like maca acquire high altitude adaptation within short geological period. Here, we report the high-quality genome assembly of maca, in which two close-spaced maca-specific whole genome duplications (WGDs, ～ 6.7 Mya) were identified. Comparative genomics between maca and close-related Brassicaceae species revealed expansions of maca genes and gene families involved in abiotic stress response, hormone signaling pathway and secondary metabolite biosynthesis via WGDs. Retention and subsequent evolution of many duplicated genes may account for the morphological and physiological changes (i.e. small leaf shape and self-fertility) in maca for high altitude environment. Additionally, some duplicated maca genes under positive selection were identified with functions in morphological adaptation (i.e. LEAF CURLING RESPONSIVENESS) and abiotic stress response (i.e. GLYCINE-RICH RNA-BINDING PROTEINS and DNA-DAMAGE-REPAIR/TOLERATION 2). Collectively, the maca genome provides useful information on the important roles of WGDs in plant high altitude adaptation in the Andes.

参考文献：

1. Zhang, J., Tian, Y., Yan, L., Zhang, G., Wang, X., Zeng, Y., ... & Wang, Y. (2016). Genome of plant maca (Lepidium meyenii) illuminates genomic basis for high altitude adaptation in the central Andes. Molecular plant.

2. 张亮生课题组参与Maca基因组研究工作. http://www.fafu.edu.cn/jyzyjzx/42/ba/c2826a148154/page.psp

3. Wikipedia.org

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