香花枇杷质体基因组序列密码子偏性分析

选取香花枇杷质体基因组进行密码子使用偏好性的生物信息学分析，用于理解其密码子使用偏性的主要原因，为今后该属植物基因的进化、起源以及转化体系中载体构建等方面研究提供借鉴。利用Codon W 1.4.2、SPSS statistics 17.0、Excel 2016和cusp等软件对筛选出的37条基因编码序列密码子进行最优密码子分析、中性绘图分析、ENC-plot和PR2-plot绘图分析。结果表明，ENC平均值为47.02；GC₃与GC₁、GC₂的相关性均不显著；GC_all为39.08%，GC₁（48.79%）>GC₂（40.18 %）>GC₃（28.44%）；RSCU>1的29个密码子中有28个以A或U结尾；PR2-plot绘图分析显示多数位点偏离中心，落于左下方位置；确定了UUU、UUG、CUU等15个最优密码子。香花枇杷叶绿体基因组中，同义密码子的使用偏性较弱（47.02）；密码子的第1、 2位碱基组成比较相似，但均不同于第3位；整体A、U含量大于C、G，末位碱基以A、U为主，且嘧啶的使用频率高于嘌呤；香花枇杷叶绿体基因组密码子的使用模式主要受到选择、突变的和其他因素的综合作用影响。

Codon Usage Bais in Chloroplast Genome of Eriobotrya fragrans Champ.ex Benth.

Codon usage pattern of the chloroplast genome of Eriobotrya fragrans was analyzed to provide useful references for the further studies on the genetic evolution,origin and vector construction in the transformation system of the plants of Eriobotrya genus.The selected 37 coding DNA sequences were used to conduct the analyses of optimal codons,neutrality test,ENC-plot and PR2-plot by using Codon W 1.4.2 software,SPSS statistics 17.0 program,and online program CUSP.The average ENC was 47.02.The correlations between GC₃&GC₁,GC₃&GC₂were not significant.The GC₁,GC₂ and GC₃ of codons in the plastome of E.fragrans was 48.79%,40.18%,and 28.44%,respectively.Among the 29 coding genes with the RSCU values over 1.0,28 genes ended with U or A.The PR2-plot showed that most of points fell in the lower left region.UUU,UUG,CUU and other 15 codons were determined as optimal codons.The codon usage bias of E.fragrans was relatively weak (47.02).The first and second base compositions of codons were similar but they were both different from that of the third position.The codons were rich in A/U and preferred to end with A/U.Pyridine was used more frequently than purine.The codon usage bias in the plastome of E.fragrans was formed under effects of mutation and selection pressure mainly,as well as other factors.