中文摘要：

以甜瓜蔗糖转化酶基因序列为材料，研究甜瓜蔗糖转化酶基因密码子偏好性，为改良甜瓜风味与品质提供理论依据。运用在线分析软件CodonW对甜瓜蔗糖转化酶的编码序列（Codingsequence，CDS）进行密码子分析，利用Mobyle在线工具分析同义密码子相对使用度（RSCU）、有效密码子数（ENC）、Gc及GC1s、GC2s、GC3s含量。甜瓜蔗糖转化酶基因偏好于以A或T结尾的密码子。密码子ATT、GTT和AGA的RSCU值都大于1，属于共同偏好使用的密码子，而密码子GCG、CGG的RSCU值小于1，属于使用频率较低的密码子。发现密码子偏好性与亲缘关系的远近有一定的关系。要实现目的基因在外源表达系统中的成功表达和提高其表达量，可通过增加目的基因剂量，目的基因密码子优化，改善培养条件等方法实现，其中目的基因密码子优化起到了关键作用。

英文摘要：

The sequence of invertase genes of melon was used for studying the codon bias of invertase genes to provide a basis for the improvement of flavor and quality of melon. The sequence of CDS of invertase genes of melon was analyzed by Codon W program, then the Relative synonymius codon usage （RSCU） , Efective Number of Codon （ENC） , and the content of GC, GC 1 s, GC2s, GC3s were analyzed by Mobyle program.The invertase genes of melon preferred to use condons ending with A or T. ATT, GTT and AGA were common preference used codon with RSCU value more than 1.However, GCG and CGG was low frequently used codon with RSCU value less than 1. It is showed that preferences of condon has a certain relationship with genetic relationship.Successful expression of target gene in exogenous gene expression system and enhancement of its expression level were achieved through increasing the dose of the target gene, optimizing the codon of target gene, improving culture conditions and other methods, which the optimization of codon of target gene has played a key role.