Yu Mengyi, Xie Yinge, Qian Zilin, Zhong Yu, Shen Huolin, Yang Wencai
Department of Vegetable Science, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, China Agricultural University, Beijing, 100193, China.
Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education of the People's Republic of China, Beijing, 100193, China.
Mol Hortic. 2025 Aug 1;5(1):49. doi: 10.1186/s43897-025-00159-x.
Terpenoids, a group of metabolites, are important to plant development and color formation, and serve as valuable nutrients for humans. The enzyme 4-diphosphocytidyl- 2 C-methyl-D-erythritol cytidyltransferase (MCT) plays a pivotal role in the methylerythritol phosphate (MEP) pathway for terpenoid biosynthesis. However, the potential lethality of MCT mutants has hindered further exploration into its functional role in terpenoid metabolite families in plants. Here, we characterized a rare MCT mutant yfm with dwarfism, chlorosis, small leaves, and yellow fruits in tomato. Map-based cloning and sequence analysis revealed that a single nucleotide substitution in the SlMCT gene, which resulted in a point mutation (Leu297Pro) in amino acid in the mutant. Over-expression and complementation of the wild-type SlMCT in the yfm mutant restored the fruit color and the other defective phenotypes. This mutation altered the gene expressions and metabolic components in the MEP and other pathways. Consequently, the total contents of carotenoids, chlorophyll, IAA, GAs, and SA were decreased, while the contents of CK, JA, and ABA were increased. Eventually, these alterations led to changes in plant phenotypes and fruit color in yfm. These findings provide novel insights into understanding the roles of MCT on plant development and pigment biosynthesis.
萜类化合物是一类代谢产物，对植物发育和颜色形成很重要，并且是对人类有价值的营养物质。4-二磷酸胞苷-2-C-甲基-D-赤藓糖醇胞苷转移酶（MCT）在萜类生物合成的甲基赤藓糖醇磷酸（MEP）途径中起关键作用。然而，MCT突变体的潜在致死性阻碍了对其在植物萜类代谢产物家族中功能作用的进一步探索。在此，我们鉴定了番茄中一个罕见的MCT突变体yfm，其具有矮化、黄化、小叶和黄色果实的特征。基于图谱的克隆和序列分析表明，SlMCT基因中的单核苷酸替换导致突变体氨基酸发生点突变（Leu297Pro）。在yfm突变体中过表达和互补野生型SlMCT恢复了果实颜色和其他缺陷表型。这种突变改变了MEP和其他途径中的基因表达和代谢成分。因此，类胡萝卜素、叶绿素、IAA、GA和SA的总含量降低，而CK、JA和ABA的含量增加。最终，这些变化导致了yfm中植物表型和果实颜色的改变。这些发现为理解MCT在植物发育和色素生物合成中的作用提供了新的见解。
