内外因子对栀子西红花苷生物合成的调控机制研究

Crocin found in the fruits of gardenia (G.jasminoides) and the stigmas of saffron (C.sativus) is a water-soluble carotenoid, and it possesses an greant value both in medical and edible field. However crocin is very expensive because of scarce natural resources, and application of crocin was seriously hampered. At present our understanding for crocin is mostly confined to the biochemical level.The study at the molecular basis and physiological level is rather weak, and regulatory mechanism of crocin synthesis is still unknown.Based on transcriptome data at different stages of fruit maturation from G.jasminoides, we will deeply analyze transcriptional profile of Gardenia fruit, and discover, identify and clone key genes in crocin biosynthesis. Genetic transformation system of G.jasminoides will be established with callus as recipient materials. Thus, the gene functional identification platform of G. jasminoides will be built. With this platform, the interactions and the biological function of key genes involved in crocin synthesis process would be systematically studied, and molecular mechansim regulated crocin biosynthesis will be researched. In parallel, the reseach that temperature and other ecological factors have effects on accumulation of crocin will be done systematically. According to the results, regulatory network of crocin biosynthesis will be build. Consequently, this study will not only help to provide new gene pool and lay the foundation for further breeding new germplasm with high crocin content using genetic engineering techniques, but also provide an important technical reference for high-yield cultivation of improved varieties.

西红花苷是一种存在于番红花和栀子等少量植物中的水溶性类胡萝卜素，具有重要的食用和药用价值，但西红花苷来源稀少，价格昂贵，严重限制了其发展应用。目前，我们对西红花苷的研究仅限于生化水平，分子和生理水平研究比较薄弱，西红花苷合成调控机制尚不明了。本项目以栀子果实不同发育阶段转录组数据为切入点，深度解析栀子果实发育转录表达谱，挖掘、鉴定和克隆西红花苷合成关键基因；建立栀子愈伤组织遗传转化受体系统，搭建栀子基因功能验证的新平台，并利用该平台解析西红花苷合成关键基因的生物学功能，探索栀子中西红花苷合成的分子调控机制；同时，系统研究温度、水分等生态外因对西红花苷积累的影响，探索外因对其合成的调控作用；综合内外因影响西红花苷积累的研究结果，构建栀子中西红花苷生物合成的调控网络。该项目研究不仅为利用基因工程技术培育高西红花苷含量的栀子新种质提供新的基因源，而且还为栀子良种高效培育提供重要的技术参考。

西红花苷具有重要的药用价值和食用价值，仅存在于西红花和栀子等少量植物中，栀子因种植面积广和西红花苷含量高等原因而有望成为西红花苷主要来源。为提高栀子中西红花苷的产量和质量，项目从遗传（内因）和生态环境（外因）两方面解析西红花苷合成调控机制，首先利用全长转录组测序技术和生物信息技术，挖掘和筛选出46个基因和91个lncRNAs参与西红花苷合成调控，选取UGT86A1、 UGT85A2、CCD4、CCD4-2、ALDH2C4-2等5个关键调控基因进行克隆、过量表达载体构建及功能验证研究，发现UGT86A1负调控西红花苷合成，而UGT85A2、CCD4、CCD4-2、ALDH2C4-2正调控西红花苷的合成，且在拟南芥中调控激素代谢途径，导致莲座叶发育不正常和提早进入生殖期；其次研究了生态环境因子对栀子西红花苷合成与积累的影响，发现土壤中的有效硼、速效磷以及相对湿度是影响栀子果实中西红花苷I合成的主导生态因子；最后通过基因与环境互作分析揭示基因型与环境互作效应是引起含量变异的最主要因素，其次是基因型，并筛选出基因型HC20栀可作为优良无性系在参试地区推广栽培。项目成果为高西红花苷含量栀子良种培育及其高效栽培提供了重要的技术参考。项目部分成果发表论文4篇，录用1篇，投稿2篇， 6人职称成功晋升，引进硕士1名，开展学术交流4次。