柑橘衰退病毒（CTV）引起的衰退病是柑橘产业上极具经济重要性的病害，随着研究领域的扩展和深入，发现CTV不仅在栽培柑橘上发生普遍，而且原生林中生长着的野生柑橘也携带CTV。中国是柑橘主要起源中心，目前在江西崇义、湖南宜章、道县的原生林中仍生存着丰富的野生柑橘品种，是植物群落长期进化发展的产物，属于古老的植物群落。本项目在前期已明确野生柑橘与栽培柑橘上CTV种群遗传特征的基础上，运用进化生物学与分子系统地理学方法对收集自野生柑橘和栽培柑橘上的CTV分离株作为两种不同生境中的CTV地理种群进行分析，明确不同生境中CTV的地理种群分化水平指标、种群间基因流程度及CTV与不同寄主协同进化特征，揭示CTV在不同生境条件下种群间的基因流、种群演化及扩散传播特点。研究结果将为解析CTV的种群进化、起源研究提供重要依据，对我国柑橘生产中开展CTV种群变异和扩散传播监测、制定综合治理策略提供技术和决策支持。

Citrus tristeza virus (CTV; genus Closterovirus, family Closteroviridae) is the causal agent of most economically important viral disease of citrus growing countries worldwide. Further more study showed that the most cultivated citruses were infected by CTV, and the wild citrus plants from the wild citrus virgin forest could be also infected by CTV. So far, with the recent knowledge of the three wild citrus virgin forests has been found in the world, they are all located in China, namely Yizhang county, Daoxian county in Hunan province and Chongyi county in Jiangxi province. The biocoenosis of virgin forests in the above three regions have long geological history, the wild citrus was the ancient citrus plant. In previous work, we analyzed the genetic characteristics of CTV isolates from wild citrus virgin forests and cultivated citrus. The objective of this study was to investigate the level of population differentiation, gene flow among populations CTV of wild citrus and cultivated citrus, and the co-evolutionary characteristics of CTV and different hosts, with the analysis methods of evolutionary biology and molecular phylogeography, to reveal the degree of population differentiation, the gene flow patters, and the population dispersal patters of CTV populations under different environment conditions, and to provide theoretical data for analysing the population evolution, origin and population dispersal of Citrus tristeza virus, and provide technical and decision support for the monitoring of CTV population variation, dispersal and designing strategies to control the tristeza disease.