抗坏血酸是人类及植物不可缺少的营养成分和生长因子。抗坏血酸合成代谢基础途径已经清晰，然而植物抗坏血酸合成调控机制和遗传基础尚不清晰。项目组前期利用GWAS鉴定了抗坏血酸合成积累关键基因bHLH59，然而bHLH59调控靶位点及协同调控因子尚不明确，功能变异位点有待鉴定。本项目在鉴定bHLH59及其对抗坏血酸合成调控基础上，通过Chip-seq等方法鉴定bHLH59靶基因，利用IP-MS等技术确定bHLH59互作蛋白，通过GUS/LUC系统等方法确定bHLH59启动子有益变异和结合蛋白。项目从转录因子bHLH59靶基因、互作蛋白和启动子结合蛋白三个层面，解析bHLH59对抗坏血酸合成积累的分子机制。bHLH59调控抗坏血酸生物合成机制的揭示，有助于加深抗坏血酸合成调控机理的认识，解析抗坏血酸积累的遗传基础，并创制高维生素C的番茄新种质，具有重要科学和实践意义。

Ascorbic acid is indispensable nutrient as well as growth factor for both human beings and plants. The basic pathways of ascorbic acid biosynthesis and metabolism have been elucidated, while the regulation mechanism and genetic basis for plant ascorbic acid biosynthesis are still elusive. The key gene of ascorbic acid biosynthesis and accumulation, bHLH59, was identified by GWAS in the early stage of the project. However, the regulatory targets and co-regulatory factors of bHLH59 are still unclear, and the functional variation sites need to be identified. Based on the identification of bHLH59 and its regulation on the biosynthesis of ascorbic acid, the target gene of bHLH59 is to be identified by Chip-seq, the interacting protein of bHLH59 will identified by IP-MS, and the beneficial mutation and binding proteins of bHLH59 promoter will be determined by GUS/LUC system. The project will analyze the molecular mechanism of ascorbic acid biosynthesis and accumulation in bHLH59 from three aspects: transcription factor bHLH59 target gene, interacting protein and promoter binding protein. Revealing the mechanism of bHLH59 regulating ascorbic acid biosynthesis is beneficial to deepen the understanding of the regulation mechanism of ascorbic acid biosynthesis, to analyze the genetic basis of ascorbic acid accumulation, and create new tomato germplasm with high vitamin C, which is of highly scientific and practical significance.