背景:柑橘病毒(CTV)是柑橘产业最严重的威胁之一,并且存在于野生和栽培柑橘中。在中国,CTV的起源和传播模式仍然知之甚少。
方法:在本研究中,收集了524份来自中国的CTV可疑柑橘样品,包括354个栽培柑橘样本和174个野生柑橘样本。最后,从中国10个柑橘产地获得了126个带有时间戳的CTV外壳蛋白序列。对中国的CTV起源和扩散模式进行了贝叶斯系统动力学推断。
结果:我们发现CTV主要分布在中国南部和沿海地区。CTV的替代率为4.70×10-4个子/站点/年(95%可信区间:1.10×10-4个子/站点/年~9.10×10-4个子/站点/年),1990年至2006年间,CTV人口略有增加的趋势。中国的CTV分离株在1875年左右共有一个最常见的最近祖先(95%可信区间:1676.57~1961.02)。中国的CTV起源于湖南和江西的野生柑橘,然后从野生柑橘传播到四川种植地区的栽培柑橘,重庆,湖北,福建,浙江,广西和广东省。
结论:这项研究证明,中国的CTV起源于湖南和江西的野生柑橘。时空分布和扩散模式揭示了CTV的人口和流行历史,为更好地了解CTV在中国的传播和起源提供线索。
Citrus tristeza virus (CTV) is one of the most serious threats to the citrus industry, and is present in both wild and cultivated citrus. The origin and dispersal patterns of CTV is still poorly understood in China.
In this study, 524 CTV suspected citrus samples from China were collected, including 354 cultivated citrus samples and 174 wild citrus samples. Finally, 126 CTV coat protein sequences were obtained with time-stamped from 10 citrus origins in China. Bayesian phylodynamic inference were performed for CTV origin and dispersal patterns study in China.
We found that CTV was mainly distributed in southern and coastal areas of China. The substitution rate of CTV was 4.70 × 10- 4 subs/site/year (95% credibility interval: 1.10 × 10- 4 subs/site/year ~ 9.10 × 10- 4 subs/site/year), with a slight increasing trend in CTV populations between 1990 and 2006. The CTV isolates in China shared a most common recent ancestor around 1875 (95% credibility interval: 1676.57 ~ 1961.02). The CTV in China was originated from wild citrus in Hunan and Jiangxi, and then spread from the wild citrus to cultivated citrus in the growing regions of Sichuan, Chongqing, Hubei, Fujian, Zhejiang, Guangxi and Guangdong provinces.
This study has proved that CTV in China was originated from wild citrus in Hunan and Jiangxi. The spatial-temporal distribution and dispersal patterns has uncovered the population and pandemic history of CTV, providing hints toward a better understanding of the spread and origin of CTV in China.