Genetic Evolution Analysis on Wild Isolates of Citrus Tristeza Virus Originated in China Based on Coat Protein Genes Sequences

作     者：YI Long ZHOU Chang-yong ZHOU Yan LI Zhong-an 

作者机构：Citrus Research Institute Southwest University~Citrus Research Institute Chinese Academy of Agricultural Sciences Chongqing 400712 P.R. China Jiangxi Navel Orange Engineering and Technology Research Center Gannan Normal University Ganzhou 341000 P.R.China 

出 版 物：《Agricultural Sciences in China》 (中国农业科学（英文版）)

年 卷 期：2010年第9卷第11期

页      面：1623-1629页

核心收录：

学科分类：0710[理学-生物学] 07[理学] 08[工学] 09[农学] 071007[理学-遗传学] 0904[农学-植物保护] 090401[农学-植物病理学] 0901[农学-作物学] 090402[农学-农业昆虫与害虫防治] 0836[工学-生物工程] 090102[农学-作物遗传育种] 

基　　金：supported by the National Natural Science Foundation of China (30900977) the Key Project 210111 of Chinese Ministry of Education and Natural Science Foundation Project of CQ CSTC (2009BB1310) 

主　　题：wild type citrus citrus tristeza virus sequence comparison phylogenetic evolution 

摘      要：The coat protein （CP） genes were cloned and sequenced from viral particles of 11 isolates of citrus tristeza virus （CTV） collected from wild citrus plants in China and 4 Chinese isolates from cultivated sweet orange and pummelo varieties, respectively. By analyzing and comparing the nucleotide and amino acid sequences of CP genes, the 11 wild CTV isolates were found over 92% identical with 4 Chinese CTV isolates and 21 exotic CTV isolates from cultivated citrus. From 91 to 100% of the CTV CP gene sequences in wild type citrus plants were generally well conserved. Genetic evolution analysis indicated that the GC% of the CP gene was less than AT%, and more transition were found in the CP genes than transversion with the transition/transversion ratio ranging from 6.3 to 7.0 among species. The substitution frequency was the highest at the third codon, followed by the first and second codon. The ratio of non-synonymous mutations （du） to synonymous mutations （ds） was far lower than 1, suggesting that the CP gene might have experienced purifying selection in the evolution. Phylogenetic analysis revealed that the 11 CTV isolates in Chinese wild type citrus belonged to different phylogenetic clusters, and shared higher homology and closer relationships with other cultivated citrus CTV isolates from different countries, which indicated complicated genetic relationships among the CTV isolates. In addition, CTV isolates with similar biological characteristics usually located into the same clusters. Therefore, the conclusion was drawn that pathogenicity was critical to evolution and origin of CTV.