中文摘要：

查尔酮合成酶（Chalcone synthase,CHS）是参与合成植物苯丙烷类物质的主要酶类之一。研究豆科植物CHS基因密码子的偏好性,对提高豆科植物CHS基因的表达水平具有重要意义。为此,运用CHIPS、CUSP和Codon W程序分析豆科植物CHS基因密码子的偏好性,并用决明CHS基因对分析结果的可信度进行验证。结果表明,在豆科植物CHS基因的密码子中,以A或U结尾的密码子偏好性较强。基于CHS基因RSCU值的聚类结果显示,豆科植物与茄科植物（包括烟草）聚为一类,表明烟草作为研究豆科植物CHS基因功能的模式植物较为合适。通过对决明CHS基因密码子偏好性与大肠杆菌和酵母基因组密码子偏好性的比较,发现两者均存在差异,但酵母的差异低于大肠杆菌,表明酵母表达系统更加适合作为决明CHS基因的外源表达系统。然而,若要使决明CHS基因能够在酵母表达系统中高效表达,仍需对其密码子进行优化。

英文摘要：

Chalcone synthase（CHS） is one of the key enzymes in the phenylaprapanoid metabolism pathways.The research about codon bias from CHS genes of leguminous plants has great significance to increase the expression level of CHS gene.Therefore,codon bias of CHS gene from leguminous plants was analyzed by Codon W,CHIPS and CUSP.Furthermore,CHS gene from Senna tora was used to verify the reliability of analysis results.According to the results,CHS gene of leguminous plants preferred to use the synonymous codons ended with A or U.The phylogenic analysis showed that Legumes and Solanaceae were attributed to one class,indicating tobacco was the optimum model plants for CHS genes functional study.Compared with E.coli and yeast genome,the codon usage difference between CHS gene of Senna tora and E.coli genome was more apparently than that between CHS gene of Senna tora and yeast genome.Hence,the yeast may be more suitable for the expression of CHS gene of Senna tora.In order to improve the expression level of CHS gene in the yeast expression system,CHS gene codons should be optimized.