High codon adaptation in citrus tristeza virus to its citrus host.
BACKGROUND
Citrus tristeza virus (CTV), a member of the genus Closterovirus within the family Closteroviridae, is the causal agent of citrus tristeza disease. Previous studies revealed that the negative selection, RNA recombination and gene flow were the most important forces that drove CTV evolution. However, the CTV codon usage was not studied and thus its role in CTV evolution remains unknown.


RESULTS
A detailed comparative analysis of CTV codon usage pattern was done in this study. Results of the study show that although in general CTV does not have a high degree of codon usage bias, the codon usage of CTV has a high level of resemblance to its host codon usage. In addition, our data indicate that the codon usage resemblance is only observed for the woody plant-infecting closteroviruses but not the closteroviruses infecting the herbaceous host plants, suggesting the existence of different virus-host interactions between the herbaceous plant-infecting and woody plant-infecting closteroviruses.


CONCLUSIONS
Based on the results, we suggest that in addition to RNA recombination, negative selection and gene flow, host plant codon usage selection can also affect CTV evolution.
College of Life and Environmental Science, Hangzhou Normal University, Hangzhou, 310036, China. conicheng_xf@126.com
Xiao-fei
XF
Cheng
Xiao-yun
XY
Wu
Hui-zhong
HZ
Wang
Yu-qiang
YQ
Sun
Yong-sheng
YS
Qian
Lu
L
Luo
D000220:Adaptation, Biological; D002957:Citrus / Q000821:virology*; D017790:Closterovirus / Q000235:genetics*; D003062:Codon; D010935:Plant Diseases / Q000821:virology*; D012641:Selection, Genetic
D003062:Codon