Lycopene cyclization is an important branching point in the synthesis of carotenoids. There are two kinds of lycopene cyclase LCYB and LCYE in plants. Previous studies have found that the differential expressions of OfLCYB1,OfLCYE1 and other genes determine the contents of downstream products of carotenoid metabolism in different varieties of Osmanthus fragrans. In this study,1028 bp and 904 bp of the OfLCYB and OfLCYE promoters were cloned by genome walking with the genomic DNA of cultivar'Yanhong Gui'as the template. The bioinformatics analysis discovered two promoter sequences that contained TATA-box and CAAT-box,also the TCA-element of salicylic acid, and some photoresponsive elements such as Sp1,ACE,Box4,and G-box. The OfLCYB promoter also includes abscisic acid response element ABRE,gibberellin response element P-box. OfLCYE promoter includes gibberellin response element GARE-motif and thermal response element HSE. The cloned promoter fragment was recombined with pBI121 vector,and the plant expression vector was constructed and transferred into Agrobacterium tumefaciens. The tobacco leaf was used for transient expression. The results proved that OfLCYB and OfLCYE promoter fragments all had the function of driving downstream reporter gene expression.%番茄红素环化是类胡萝卜素合成过程中的重要分支点,植物中存在两种番茄红素环化酶LCYB和LCYE.前期研究发现,OfLCYB1、OfLCYE1等基因的差异表达决定了桂花不同品种中类胡萝卜素代谢分支下游产物的含量不同.以'堰虹桂'基因组DNA为模板,通过染色体步移的方法(Genome walking)克隆出OfLCYB和OfLCYE启动子分别为1028 bp和904 bp.通过生物信息学分析发现两个启动子序列包含TATA-box、CAAT-box等基本元件,同时都含有水杨酸响应元件TCA-element,以及一些光响应元件如Sp1、ACE、Box4、G-box等;OfLCYB启动子还包括脱落酸响应元件ABRE,赤霉素响应元件P-box,OfLCYE启动子包括赤霉素响应元件GARE-motif及热击响应元件HSE.将克隆到的启动子片段与pBI121载体进行重组,构建植物表达载体并转入农杆菌,采用叶盘法侵染烟草叶片进行瞬时表达.结果表明,OfLCYB和OfLCYE启动子片段均具有驱动下游报告基因表达的功能.
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