以栽培型向日葵'龙赏葵1号'为供试材料,筛选出51条叶绿体基因组CDS,进行密码子使用特征分析.利用Codon W 1.4.2、SPSS和在线软件CUSP,进行中性绘图、ENC-plot和PR2-plot分析,并筛选最优密码子.结果显示:'龙赏葵1号'向日葵叶绿体基因组密码子各位置GC含量为GC1(47.14%)>GC2(39.44%)>GC3(28.42%),密码子末位碱基以A/T为主;ENC取值范围为39.13~59.17,ENC>45的基因共有38个,密码子使用偏好性较弱;RSCU>1的密码子有30个,其余29个以A/U结尾,偏好性明显;相关分析发现,其密码子使用偏好主要受自然选择影响;高频和高表达相结合的方法确认12个密码子为最优密码子,分别为CUU、AUA、CCA、ACU、GCU、UAU、UAG、CAU、AAA、GAU、AGU、GGA.
Analysis of Codon Usage Bias in Chloroplast Genome of Cultivated He-lianthus annuus
Using cultivated Helianthus annuus'Longshangkui No.1'as the test material,51 chloroplast genome CDSs were screened out,and the codon usage characteristics were analyzed.Choose Codon W 1.4.2,SPSS and on-line software CUSP,perform neutral plotting,ENC-plot and PR2-plot analysis,and screen the best codons.The re-sults showed that the GC content of each codon in the chloroplast genome of H.annuus'Longshangkui No.1'was GC1(47.14%)>GC2(39.44%)>GC3(28.42%),and the last base of the codon was mainly A/T;the value of ENC ranges from 39.13 to 59.17,there are 38 genes with ENC>45,and the codon usage bias is weak;there are 30 codons with RSCU>1,and the remaining 29 end with A/U,which have obvious bias;correlation analysis found that its codon usage preference is mainly affected by natural selection;through the method of combining high fre-quency and high expression,12 codons were confirmed as optimal codons,namely CUU,AU A,CCA,ACU,GCU,UAU,UAG,CAU,AAA,GAU,AGU,GGA.