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草业学报 ›› 2023, Vol. 32 ›› Issue (7): 85-95.DOI: 10.11686/cyxb2022332

• 研究论文 • 上一篇    下一篇

白羊草叶绿体基因组密码子使用偏好性分析

高守舆(), 李钰莹(), 杨志青, 董宽虎(), 夏方山   

  1. 山西农业大学草业学院,山西 晋中 030801
  • 收稿日期:2022-08-17 修回日期:2022-11-04 出版日期:2023-07-20 发布日期:2023-05-26
  • 通讯作者: 李钰莹,董宽虎
  • 作者简介:E-mail: dongkuanhu@sxau.edu.cn
    E-mail: liyuy_ing@163.com
    高守舆(2000-),男,内蒙古巴彦淖尔人,在读硕士。E-mail: gaoshouyu2022@163.com
  • 基金资助:
    山西农业大学科技创新基金项目(2017YJ06);山西农业大学“十四五”生物育种工程项目(YZGC134);山西省重点研发计划项目(201903D221091)

Codon usage bias analysis of the chloroplast genome of Bothriochloa ischaemum

Shou-yu GAO(), Yu-ying LI(), Zhi-qing YANG, Kuan-hu DONG(), Fang-shan XIA   

  1. College of Grassland Science,Shanxi Agricultural University,Jinzhong 030801,China
  • Received:2022-08-17 Revised:2022-11-04 Online:2023-07-20 Published:2023-05-26
  • Contact: Yu-ying LI,Kuan-hu DONG

摘要:

叶绿体基因组具有高度的保守性和较慢的进化速率,研究叶绿体基因组密码子偏好性可以明确基因表达效率,确定植物系统发育和物种进化。为解析白羊草及其近缘种的系统发育关系,利用CAIcal和CodonW 1.4.2等软件分析了白羊草的叶绿体基因组密码子使用模式,并利用白羊草及其近缘种的同义密码子相对使用度(RSCU)数据构建了聚类图。结果显示:经筛选后的白羊草叶绿体基因组序列中GC的平均含量为38.79%,其中GC1>GC2>GC3;密码子第3位碱基多为A或U;有效密码子数(ENC)的取值为36~61,密码子偏好性较弱;高频率使用的密码子共计26个,其中25个高频密码子以A或U结尾。结合中性绘图、ENC-plot、ENC比值和PR2-plot分析,结果表明白羊草叶绿体基因的密码子偏好性同时受到突变压力和自然选择的影响,且突变压力的影响较大。RSCU数据分析共筛选出15个最优密码子,均以A或U结尾。RSCU聚类结果显示白羊草在密码子使用模式上与近缘物种有所不同。本结果可为孔颖草属植物系统发育研究提供参考。

关键词: 叶绿体基因组, 白羊草, 密码子偏好性, 最优密码子

Abstract:

The chloroplast genome is highly conserved and has a slow evolutionary rate. The study of chloroplast genome codon bias could clarify the expression efficiency of genes, and could even determine plant phylogeny and species evolution. In order to analyze the phylogenetic relationship between Bothriochloa ischaemum and its related species, we analyzed the codon usage pattern of the chloroplast genome of B. ischaemum using CAIcal and CodonW1.4.2 software, and a cluster map was constructed using relative synonymous codon usage (RSCU) of B. ischaemum and its related species. Results showed that the average guanine-cytosine (GC) content was 38.79% in the B. ischaemum chloroplast genome sequences which had been screened, and the content was GC1>GC2>GC3. In these sequences, the third base of the codon was mostly A or U. The number of effective codons (ENC) ranges from 36 to 61 and indicates that the codon bias of B. ischaemum is weak. In addition, a total of 26 codons are used with high frequency, among which 25 codons end in A or U. Combined with the analyses of neutral plot, ENC-plot, ENC ratio and PR2-plot, we found that the codon bias of chloroplast genes of B. ischaemum is affected by both mutation pressure and natural selection, and the effect of mutation pressure is greater. Through the RSCU data analysis, a total of 15 optimal codons were screened from B. ischaemum chloroplast genome, and all of these end in A or U. In the present study, RSCU clustering showed that the codon usage pattern of B. ischaemum is different from that of related species. The present study therefore provides a reference for phylogenetic study of plants of the genus Bothriochloa.

Key words: chloroplast genome, Bothriochloa ischaemum, codon usage bias, optimal codons