杜氏盐藻是迄今为止工业化生产β-胡萝卜素最成功的经济微藻之一，番茄红素β-环化酶（LycB）是催化番茄红素合成β-胡萝卜素的关键酶。本研究根据实验室克隆得到的LycB的cDNA序列，通过分析其保守序列设计引物，通过分段克隆PCR及基因组步移的方法，克隆获得几乎完整的LycB基因组序列。测序结果表明，克隆到的该部分LycB基因组序列含有5863 bp，由11个外显子和10个内含子组成。再通过基因组步移的方法，获得LycB基因启动子和终止子序列。其中，5’端上游序列长度为2566 bp，3’端下游序列长度为818 bp。采用PlantPAN在线启动子预测工具进行分析，结果表明，该基因启动子含有一些顺式作用元件如光响应元件、盐响应元件等，表明巴氏杜氏藻LycB基因的表达可能受到光照及盐浓度等因素的调控。

The unicellular green alga Dunaliella bardawil has been successfully used for natural production of β-carotene. Lycopene β-cyclase (LycB) is one of the key enzymes for the synthesis of β-carotene, which can catalysis lycopene to form β-carotene. In this research, based on the full-length sequence of LycB cDNA of D. bardawil previously coloned by our group, primers were designed and genomic sequence of LycB were isolated by analysis of the conserved region of LycB gene from other species in database and by using the approach of PCR with genome walking techniques. Sequence results showed that nearly full-length of LycB genomic sequence of 5863 bp was achieved, which included 11 exons and 10 introns. Then, two sets of primers were designed according to the LycB genomic sequence. The promoter and terminator of LycB were obtained using genome walking techniques. Based on the analysis of PlantPAN, some cis-acting elements such as light-induced responsive element and salt- induced responsive element were predicted in promoter sequence, implying that the LycB gene expression may be regulated by light and salt.

国家自然科学基金项目（31171631）