Abstract:

To clarify the codon usage characteristics of CqGAI gene， the sequence of CqGAI gene was cloned. The codon usage preference of CqGAI gene was analyzed using CodonW， SPSS software and EMBOSS online program， and neutral mapping， ENC analysis and parity preference bias analysis were performed with GAI genes of 25 plants. The results showed that the length of coding sequence （CDS） of CqGAI gene was 1 782 bp， which encoded 593 amino acids， and contained the unique structural domains of DELLA gene family such as DELLA， TVHYNP， NLS， VHIID， LHR and RVER. The CqGAI gene could rapidly responded to gibberellines （GA），_{whichplayed a key role in the GA signaling pathway. Codon bias analysis showed that ENC， CAI and GC content of CqGAI gene were 54.14， 0.21 and 46.18%， respectively， with weak codon bias， preference ending with A/T and 27 high frequency codons. The clustering analyses showed that the CqGAI gene had the closest preference to Caryophyllales. The base composition and correlation analysis revealed that the codon preference of CqGAI gene was influenced by selection effect and base mutation. The frequency of codon usage indicated that both Escherichia coli and yeast were suitable for heterologous expression of CqGAI gene， and Arabidopsis thaliana， Nicotiana tabacum and Beta vulgaris were suitable for genetic transformation recipients for functional analysis of CqGAI gene. Above results provided an important reference for further study the function and heterologous expression of CqGAI gene.}

Key words: Chenopodium quinoa, CqGAI gene, codon usage bias, evolution analysis

摘要：

为了阐明藜麦CqGAI基因密码子使用特性，克隆获得藜麦CqGAI基因序列，运用CodonW、SPSS软件及EMBOSS在线程序分析藜麦CqGAI基因密码子使用偏好性，并与25种植物的GAI基因进行中性绘图、ENC分析和奇偶偏好偏差性分析。结果表明，藜麦CqGAI基因编码序列（coding sequence，CDS）全长1 782 bp，编码593个氨基酸，包含DELLA基因家族特有结构域DELLA、TVHYNP、NLS、VHIID、LHR、RVER；CqGAI基因能够迅速响应赤霉素（gibberellins，GA），在GA信号通路中起关键作用；密码子偏好性分析显示，CqGAI基因的有效密码子数（effective number of codon，ENC）、密码子适应指数（codon adaptation index， CAI）及GC含量分别为54.14、0.21和46.18%，密码子偏好性较弱，偏好以A/T结尾，有27个高频密码子。聚类分析表明，藜麦CqGAI基因与石竹目植物的亲缘关系较近。碱基组成与相关性分析发现，CqGAI基因密码子偏好性受碱基突变和选择效应影响。密码子使用频率表明，大肠杆菌与酵母菌均适用于藜麦CqGAI基因异源表达，拟南芥、烟草、甜菜均可作为藜麦CqGAI基因功能分析的遗传转化受体。以上研究结果为进一步研究藜麦CqGAI基因功能和异源表达提供了重要参考。

关键词: 藜麦, CqGAI基因, 密码子偏好性, 进化分析