Hypericum perforatum is among the most commonly used herbal remedies and supplements. The aerial plant parts are often used to treat depression. Due to the lack of genomic information of H. perforatum, the gene networks regulating secondary metabolite synthesis remain unclear. Here, we present a high‐quality genome for H. perforatum with a 2.3‐Mb scaffold N50. The draft assembly covers 91.9% of the predicted genome and represents the fourth sequenced genus in the order Malpighiales. Comparing this sequence with model or related species revealed that Populus trichocarpa and Hevea brasiliensis could be grouped into one branch, while H. perforatum and Linum usitatissimum are grouped in another branch. Combined with transcriptome data, 40 key genes related to melatonin, hyperforin, and hypericin synthesis were screened and analyzed. Five N‐acetylserotonin O‐methyltransferases (HpASMT1‐HpASMT5) were cloned and functionally characterized. Purified HpASMT3 protein converted N‐acetylserotonin into melatonin with a V_max of about 1.35 pkat/mg protein. HpASMT1 and HpASMT3 overexpression in Arabidopsis mutants caused 1.5‐2‐fold higher melatonin content than in mutant and wild‐type plants. The endogenous reactive oxygen species (ROS) in transgenic plants was significantly lower than ROS in mutant and wild‐type plants, suggesting higher drought tolerance. The obtained genomic data offer new resources for further study on the evolution of Hypericaceae family, but also provide a basis for further study of melatonin biosynthetic pathways in other plants.

中文翻译：

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贯叶连翘的全基因组序列数据和 N-乙酰5-羟色胺 O-甲基转移酶对褪黑激素生物合成的功能表征

贯叶连翘是最常用的草药和补品之一。地上植物部分常用于治疗抑郁症。由于缺乏贯叶连翘的基因组信息，调控次生代谢物合成的基因网络仍不清楚。在这里，我们提供了一个高质量的H基因组。 perforatum与 2.3-Mb 支架 N50。组装草图覆盖了预测基因组的 91.9%，代表了 Malpighiales 目中的第四个测序属。将该序列与模型或相关物种进行比较发现，毛果杨和巴西橡胶树可以归为一个分支，而贯叶连翘和巴西橡胶树可以归为一个分支。Linum usitatissimum被归入另一个分支。结合转录组数据，筛选分析了与褪黑激素、金丝桃素、金丝桃素合成相关的40个关键基因。克隆了五种 N-乙酰5-羟色胺 O-甲基转移酶 (HpASMT1-HpASMT5) 并对其进行了功能表征。纯化的 HpASMT3 蛋白将 N-乙酰5-羟色胺转化为褪黑激素，V _max约为 1.35 pkat/mg 蛋白。HpASMT1和HpASMT3在拟南芥中过表达突变体引起的褪黑激素含量比突变体和野生型植物高 1.5-2 倍。转基因植物中的内源活性氧（ROS）显着低于突变体和野生型植物中的 ROS，表明其具有更高的耐旱性。获得的基因组数据为进一步研究金丝桃科植物的进化提供了新的资源，也为进一步研究其他植物褪黑激素的生物合成途径提供了基础。