Key Laboratory of Bio-resource and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China.
Sanya Nanfan Research Institute of Hainan University, Hainan Yazhou Bay Seed Laboratory, Sanya, 572025, China.
Nat Commun. 2023 Sep 8;14(1):5525. doi: 10.1038/s41467-023-41307-5.
Melatonin is a functionally conserved broad-spectrum physiological regulator found in most biological organisms in nature. Enrichment of tomato fruit with melatonin not only enhances its agronomic traits but also provides extra health benefits. In this study, we elucidate the full melatonin biosynthesis pathway in tomato fruit by identifying biosynthesis-related genes that encode caffeic acid O-methyltransferase 2 (SlCOMT2) and N-acetyl-5-hydroxytryptamine-methyltransferases 5/7 (SlASMT5/7). We further reveal that red light supplementation significantly enhances the melatonin content in tomato fruit. This induction relies on the "serotonin-N-acetylserotonin-melatonin" biosynthesis route via the SlphyB2-SlPIF4-SlCOMT2 module. Based on the regulatory mechanism, we design a gene-editing strategy to target the binding motif of SlPIF4 in the promoter of SlCOMT2, which significantly enhances the production of melatonin in tomato fruit. Our study provides a good example of how the understanding of plant metabolic pathways responding to environmental factors can guide the engineering of health-promoting foods.
褪黑素是一种在自然界中大多数生物中都存在的功能保守的广谱生理调节剂。番茄果实中褪黑素的富集不仅可以增强其农艺性状，还可以提供额外的健康益处。在这项研究中，我们通过鉴定生物合成相关基因，即编码咖啡酸 O-甲基转移酶 2（SlCOMT2）和 N-乙酰-5-羟色胺甲基转移酶 5/7（SlASMT5/7），阐明了番茄果实中完整的褪黑素生物合成途径。我们进一步揭示，红光补充可显著提高番茄果实中的褪黑素含量。这种诱导依赖于通过 SlphyB2-SlPIF4-SlCOMT2 模块的“血清素-N-乙酰血清素-褪黑素”生物合成途径。基于调控机制，我们设计了一种基因编辑策略，靶向 SlCOMT2 启动子中 SlPIF4 的结合基序，从而显著提高了番茄果实中褪黑素的产量。我们的研究为如何理解植物代谢途径对环境因素的响应，从而指导具有促进健康功能的食品工程提供了一个很好的范例。
