环肽生物碱是枣“安神”活性的重要载体，也是枣属植物的特征代谢物。开展枣环肽生物碱合成及遗传变异研究，对于高环肽生物碱含量枣种质发掘与遗传改良具有重要意义。前期研究利用mGWAS定位到2个BURP domain containing protein 17 (BURP) 可能编码枣环肽生物碱合成的前体肽。以此为基础，本项目采用分子生物学技术研究上述BURP基因的时空表达和亚细胞定位；构建过表达载体并转化烟草叶片和枣树毛状根，利用LC/MS-MS靶向代谢组技术鉴定环肽生物碱含量，揭示BURP在枣环肽生物碱合成中的功能；研究BURP转录表达、启动子活性和编码区单核苷酸多态性与不同枣品种环肽生物碱积累关系，阐释枣环肽生物碱含量遗传变异的分子机理。项目研究将为解析植物环肽生物碱生物合成机制开辟新途径，为以功能品质为选育目标的枣树育种奠定基础。

The cyclopeptide alkaloids are important functional components with sedation activity in Chinese jujube (Ziziphus jujuba Mill.) and are also characteristic secondary metabolites of Ziziphus plants. Elucidating the biosynthesis and genetic variation of jujube cyclopeptide alkaloid, is of significant for exploration of higher-content cultivars and also the genetic improvement of Chinese jujube. In our previous study, two BURP domain containing protein 17 (BURP) were identified as candidate genes encoding the putative precursor peptides for the biosynthesis of jujube cyclopeptide alkaloids based on a mGWAS strategy. Therefore, the current project will begin with exploring the temporal and spatial expression and the subcellular localization of the two BURPs with several molecular biological technologies. To eventually identify the putative role of BURPs in the biosynthesis of jujube cyclopeptide alkaloids, BURP-overexpression vectors will be constructed and transformed into tobacco leaves and jujube hairy roots, the metabolites in corresponding overexpression tissues will be determined by widely targeted metabolomic with LC/MS-MS strategy. In addition, the relationships between the metabolite accumulation and the gene expression, promoter activities, or the single nucleotide polymorphism of coding regions will be further studied to elucidate the molecular mechanism of genetic variation of cyclopeptide alkaloids among different jujube cultivars. Overall, this project will break a new path for exploring the biosynthesis of cyclopeptide aklaloids in plants and will also lay a foundation for the breeding concerning selection for functional quality in Chinese jujube.