We explored the genetic diversity and molecular evolutionary characteristics of tomato spotted wilt orthotospovirus (TSWV) on tobacco in Yunnan. In this study, 523 diseased tobacco leaf samples with suspected TSWV infection from nine different geographical sources in Yunnan were tested, and nucleocapsid protein (NP) of some isolates was amplified and cloned by reverse transcription-polymerase chain reaction (RT‒PCR). Bioinformatics tools were used to analyze the population genetic structure and molecular evolutionary relationships of the tobacco TSWV population. TSWV was detected in 284 of 523 samples, with an average positivity rate of 54.3%. gene sequences of the 159 tobacco TSWV isolates obtained were all 777 bp, with 265 nucleic acid polymorphic sites, with 197 variant sites, including 66 parsimony informative and 131 single variant sites. Results for virus consistency and variation analysis based on the gene showed that the nucleotide sequence consistency of Yunnan TSWV isolates was 96∼100%, the haplotype diversity 0.963, and the nucleic acid diversity 0.006. Phylogenetic analysis revealed that Yunnan tobacco TSWV isolates belong to the same group, with lower genetic differentiation and more frequent gene exchange among tobacco isolates of different geographical origins; their geographical characteristics were not obvious, and significant recombination signals were detected in the gene sequences of the DL-20 and DL-42 isolates. Many of the gene mutations of tobacco TSWV isolates from different geographic origins were deleterious in the nine different planting regions of Yunnan tobacco TSWV isolates, with only the population in the QJ planting region experiencing past population expansion events. The findings suggest that genetic recombination, mutation, and negative selection pressure are major drivers of the genetic diversity of tobacco TSWV in Yunnan. This study report of genetic variation in populations of TSWV isolates from various tobacco regions in Yunnan and provides information on the population structure of Yunnan tobacco TSWV isolates, which can help to prevent and control TSWV on Yunnan tobacco and provide a reference for research of disease-resistant varieties of tobacco.

中文翻译：

---

云南省烟草番茄斑萎正孢病毒群体遗传多样性

我们探讨了云南烟草番茄斑萎正孢病毒（TSWV）的遗传多样性和分子进化特征。本研究对来自云南9个不同地理来源的523份疑似TSWV感染的病烟叶样本进行了检测，并通过逆转录聚合酶链反应（RT-PCR）扩增并克隆了一些分离株的核衣壳蛋白（NP）。利用生物信息学工具分析烟草TSWV群体的群体遗传结构和分子进化关系。523份样本中，有284份检测出TSWV，平均阳性率为54.3%。获得的159个烟草TSWV分离株基因序列均为777 bp，核酸多态性位点265个，变异位点197个，其中简约信息位点66个，单变异位点131个。基于基因的病毒一致性和变异分析结果表明，云南TSWV分离株核苷酸序列一致性为96～100%，单倍型多样性为0.963，核酸多样性为0.006。系统发育分析表明，云南烟草TSWV分离株属于同一类群，不同地理来源的烟草分离株之间遗传分化较低，基因交换较频繁；地理特征不明显，DL-20和DL-42分离株的基因序列中检测到显着的重组信号。来自不同地理来源的烟草TSWV分离株的许多基因突变对云南烟草TSWV分离株的9个不同种植区是有害的，只有QJ种植区的种群经历过过去的种群扩张事件。研究结果表明，基因重组、突变和负选择压力是云南烟草TSWV遗传多样性的主要驱动因素。本研究报告了云南各烟区TSWV分离株的遗传变异，提供了云南烟草TSWV分离株的种群结构信息，有助于云南烟草TSWV的防治，为病害研究提供参考。烟草的抗性品种。