Table 7_Tomato spotted wilt virus in tomato from Croatia, Montenegro and Slovenia: genetic diversity and evolution.xlsx

Tomato spotted wilt orthotospovirus (TSWV) is a major plant pathogen causing significant economic losses in tomato production worldwide. Understanding its genetic diversity and evolutionary mechanisms is crucial for effective disease management. This study analyzed TSWV isolates from symptomatic tomato plants collected across Croatia, Montenegro and Slovenia between 2020 and 2024. High-throughput sequencing (HTS) was employed to obtain whole-genome sequences, followed by phylogenetic analyses to assess genetic variability and relationships among isolates from these three countries and other isolates of worldwide geographic origin. Phylogenetic analyses placed all studied isolates within the L1-M3-S3 genotype, commonly associated with solanaceous crops in Europe. While Croatian and Slovenian isolates exhibited high genetic similarity, Montenegrin isolates clustered in a distinct subgroup, showing closer relationships to Asian and Mediterranean accessions. Despite the severe disease symptoms observed, no substitutions in the NSm protein associated with resistance-breaking (RB) phenotypes were detected. These findings suggest that additional virome components, environmental factors or so far unknown mechanism(s) may contribute to infection and disease severity in tomato and strongly support the need of continuous surveillance of TSWV genetic diversity in order to inform breeding programs and develop sustainable management strategies to mitigate future outbreaks.

番茄斑萎病毒（Tomato spotted wilt orthotospovirus, TSWV）是一类重要的植物病原菌，在全球范围内给番茄生产造成了显著的经济损失。解析其遗传多样性与进化机制，对于实施有效的病害防控策略至关重要。本研究针对2020年至2024年间，从克罗地亚、黑山及斯洛文尼亚境内采集的显症番茄植株中分离得到的TSWV毒株展开分析。研究采用高通量测序（High-throughput sequencing, HTS）技术获取了所有供试毒株的全基因组序列，随后通过系统发育分析，评估了这三个国家的毒株与全球其他地理来源毒株间的遗传变异程度及进化关系。系统发育分析结果显示，所有研究毒株均归类于L1-M3-S3基因型，该基因型在欧洲普遍与茄科作物相关联。尽管克罗地亚与斯洛文尼亚的毒株遗传相似性较高，但黑山毒株则单独聚为一个亚组，与亚洲及地中海地区的毒株亲缘关系更为紧密。尽管观测到严重的病害症状，但未检测到与抗病突破（resistance-breaking, RB）表型相关的NSm蛋白氨基酸替换。本研究结果表明，额外的病毒组组分、环境因素或迄今尚未明确的机制，可能参与了番茄的侵染过程与病害严重程度的形成；同时，本研究也强烈支持需持续开展TSWV遗传多样性监测工作，以为番茄抗病育种计划提供理论依据，并制定可持续的防控策略以缓解未来的病害暴发风险。