调控桂花CCD4基因裂解类胡萝卜素产生β-紫罗兰酮的WRKY转录因子的克隆和功能分析

桂花是我国十大名花之一，著名的芳香植物，其中在银桂品种花瓣的精油中，β-紫罗兰酮的含量最高，是花瓣中最主要的挥发油成分。我们前期的研究已经证实，在桂花花瓣中β-紫罗兰酮是由类胡萝卜素裂解双加氧酶（OfCCD1和OfCCD4）裂解类胡萝卜素产生的，尤其是OfCCD4基因在银桂整个花期表达量都非常高，花瓣中β-紫罗兰酮的含量也较高，但是该基因在丹桂花瓣中几乎不表达。OfCCD4 基因在银桂和丹桂花瓣中的差异表达是二者花瓣中β-紫罗兰酮含量差异的根本原因。在OfCCD4基因5'端上游的启动子区域含有2个W-box回文结构，说明该基因受到WRKY转录因子的调控，本项目拟从银桂花瓣中克隆出参与调控OfCCD4基因的WRKY转录因子，并利用分子生物学和遗传学手段对其功能进行验证，阐明桂花关键芳香成分β-紫罗兰酮的产生和调控机理，为桂花芳香成分的利用提供理论依据。

Widely known for its strong aroma, Osmanthus fragrans is one of China’ s top ten ornamental plants and has values far beyond the merely decorative. β-ionone is an important essential oil in Albus group cultivars. Our previous works have demonstrated that β-ionone was produced by cleavage of carotenoids, which catalyzing by OfCCD1 and OfCCD4. Especially the expression level of OfCCD4 gene is very high in Zi Yingui and almost no expression in Chenghong Dangui. The main reason for the different content of β-ionon between the 2 cultivars is different transcripts of OfCCD4 gene. The 5’ upstream of OfCCD4 gene contains 2 W-box domains, indicating that the gene is regulated by WRKY transcription factors.. In this project, we will clone one or more WRKY transcription factors involved in the regulation of OfCCD4 gene, using techniques of molecular biology and genetics analyses to clarify the generation and regulation mechanism of β-ionone.