银杏GbbZIP响应UV-B辐射调控异鼠李素合成的分子机制

异鼠李素具有保护心血管、降低血清胆固醇和促进血流畅通等功能，是评价银杏提取物品质最重要的指标之一。我们前期研究发现UV-B处理能大幅提高银杏叶异鼠李素含量；转录组数据分析表明银杏GbbZIP (Gb_12012)和几个GbMYB在响应UV-B辐射促进银杏异鼠李素合成过程中起重要作用，但其相关的分子调控机制目前尚不清楚。本项目拟通过基因表达模式、亚细胞定位、转录激活活性分析来明确GbbZIP的功能；通过银杏愈伤组织转化技术、超表达、RNAi、CHIP-Seq等技术确定关键的GbMYB；并通过酵母单杂、EMSA等技术验证GbMYB对下游功能基因GbF3’H/OMT的调控；最终阐明银杏GbbZIP响应UV-B辐射促进异鼠李素合成的分子机制，以期揭示银杏类黄酮合成调控的独特机制，为制定提高叶片异鼠李素含量的叶用银杏栽培技术提供理论依据。

Isorhamnetin plays an important role in protecting cardiovascular system, lowering serum cholesterol and promoting blood flow, which is one of the most important indexes to evaluate the quality of Ginkgo biloba extract. In our previous study, we found that UV-B treatment could significantly increase the content of isorhamnetin in G. biloba leaves. Combined with transcriptomic analysis, we identified the GbbZIP (Gb_12012) and a few GbMYBs that may play an important role in regulating G. biloba isorhamnetin synthesis in response to UV-B radiation, but the related molecular regulatory mechanism remains unclear. On this basis, we will identify the function of GbbZIP (Gb_12012) by expression pattern, subcellular localization and transcriptional activation assays in this project. On the other hand, we will apply homologous callus transformation, overexpression, RNAi and ChIP-Seq technologies to determine the key GbMYB. Moreover, we will verify how GbMYB regulate downstream functional gene GbF3’H/OMT through yeast one-hybridization and EMSA. Eventually, we will elucidate the molecular mechanism of GbbZIP (Gb_12012) responding to UV-B radiation to promote isorhamnetin synthesis in G. biloba leaves, which will contribute to unravel the specific regulatory mechanism of flavonoid synthesis in G. biloba. And it will also provide a theoretical basis for developing a technique for leaf-harvesting Ginkgo cultivation aimed at increasing the content of isorhamnetin in leaves.