Key Laboratory of Saline-alkali Vegetation Ecology Restoration (Northeast Forestry University), Ministry of Education, Harbin, 150040, China.
College of Life Science, Northeast Forestry University, Harbin, 150040, China.
Adv Sci (Weinh). 2024 May;11(19):e2309990. doi: 10.1002/advs.202309990. Epub 2024 Mar 13.
Menispermaceae species, as early-diverging eudicots, can synthesize valuable benzylisoquinoline alkaloids (BIAs) like bisbenzylisoquinoline alkaloids (bisBIAs) and sinomenines with a wide range of structural diversity. However, the evolutionary mechanisms responsible for their chemo-diversity are not well understood. Here, a chromosome-level genome assembly of Menispermum dauricum is presented and demonstrated the occurrence of two whole genome duplication (WGD) events that are shared by Ranunculales and specific to Menispermum, providing a model for understanding chromosomal evolution in early-diverging eudicots. The biosynthetic pathway for diverse BIAs in M. dauricum is reconstructed by analyzing the transcriptome and metabolome. Additionally, five catalytic enzymes - one norcoclaurine synthase (NCS) and four cytochrome P450 monooxygenases (CYP450s) - from M. dauricum are responsible for the formation of the skeleton, hydroxylated modification, and C-O/C-C phenol coupling of BIAs. Notably, a novel leaf-specific MdCYP80G10 enzyme that catalyzes C2'-C4a phenol coupling of (S)-reticuline into sinoacutine, the enantiomer of morphinan compounds, with predictable stereospecificity is discovered. Moreover, it is found that Menispermum-specific CYP80 gene expansion, as well as tissue-specific expression, has driven BIA diversity in Menispermaceae as compared to other Ranunculales species. This study sheds light on WGD occurrences in early-diverging eudicots and the evolution of diverse BIA biosynthesis.
防己科物种作为早期分化的真双子叶植物，可以合成具有广泛结构多样性的苯并异喹啉生物碱（BIAs），如双苄基异喹啉生物碱（bisBIAs）和青藤碱。然而，导致其化学多样性的进化机制尚不清楚。本文呈现了防己科轮环藤的染色体水平基因组组装，并证实了两轮全基因组复制（WGD）事件的发生，这两轮事件在毛茛目植物中共享，并且是轮环藤特有的，为理解早期分化的真双子叶植物的染色体进化提供了模型。通过分析转录组和代谢组，重建了轮环藤中不同 BIAs 的生物合成途径。此外，从轮环藤中鉴定出五个催化酶 - 一个诺卡枯林合酶（NCS）和四个细胞色素 P450 单加氧酶（CYP450s） - 负责 BIAs 骨架的形成、羟化修饰以及 C-O/C-C 酚键偶联。值得注意的是，发现了一种新型叶特异性 MdCYP80G10 酶，它可以催化（S）-阿片碱与 sophoracutine 的 C2'-C4a 酚键偶联，后者是吗啡类化合物的对映异构体，具有可预测的立体特异性。此外，与其他毛茛目植物相比，防己科特有的 CYP80 基因扩张以及组织特异性表达导致了 BIAs 多样性的产生。本研究揭示了早期分化的真双子叶植物中 WGD 的发生以及不同 BIA 生物合成的进化。
