昆虫质型多角体病毒同义密码子使用模式分析

Analysis of synonymous codon usage patterns in insect cypoviruses

昆虫质型多角体病毒(cypovirus,CPV)是害虫种群重要调节因子,可用作生物防治剂。本研究采用多元统计分析方法对7种CPV进行密码子使用模式分析,结果表明:CPV密码子使用偏好性较弱,多数基因密码子使用模式受碱基组成影响,少数基因密码子使用模式除碱基组成外还有其它影响因素;中性绘图分析表明碱基组成主要受选择压力影响,受突变影响较小。同一电泳型CPV之间比同一宿主CPV之间共有的偏好性密码子多。CPV基因组内10个基因组片段之间密码子偏好性存在差异。CPV密码子偏好性与宿主昆虫密码子偏好性存在差异,所有CPV与其宿主昆虫共有的偏好性密码子均较少。对应分析进一步证明碱基组成是影响密码子使用的主要因素,不同电泳型CPV具有不同的密码子使用模式。聚类分析表明同一电泳型CPV密码子使用模式相似,同一宿主CPV密码子使用模式差异较大。

Cypoviruses （CPVs） are key regulatory factors of pest insect populations and are considered very promising biological control agents of pest insect populations. We detailed the synonymous codon usage patterns of seven CPVs through multivariate statistical methods. The result showed that CPV possessed a general weak synonymous usage bias. The codon usage patterns of most genes were constrained by base composition, while those of few minority genes were influenced by both base composition and other factors. Neutrality plot anaylsis revealed that selective pressures dominated over mutation in shapes base composition. Same electrophoretype CPVs shared more common preferred codons than same host CPVs. The 10 genome fragments within CPVs possessed statistically different codon biases. The codon biases of CPVs were significantly different from those of their insect host. All CPVs shared few common preferred codons with their host. Correspondence analysis further confirmed that base composition was the main factor influence synonymous codon usage and different electropherotype CPVs possessed different codon usage patterns. In the cluster analysis, same electropherotype CPVs possessed similar codon usage patterns, but same host CPVs possessed dissimilar codon usage patterns.