Centro de Biotecnología y Genómica de Plantas (CBGP), Universidad Politécnica de Madrid (UPM) and Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA-CSIC) and E.T.S.I. Agronómica, Alimentaria y de Biosistemas, Campus de Montegancedo, UPM, 28223 Pozuelo de Alarcón, Madrid, Spain.
School of Agriculture, Food and Wine, University of Adelaide, Adelaide, SA 5005, Australia.
Phytopathology. 2023 Sep;113(9):1697-1707. doi: 10.1094/PHYTO-11-22-0439-V. Epub 2023 Nov 1.
Host ranges of plant viruses are poorly known, as studies have focused on pathogenic viruses in crops and adjacent wild plants. High-throughput sequencing (HTS) avoids the bias toward plant-virus interactions that result in disease. Here we study the host ranges of tobamoviruses, important pathogens of crops, using HTS analyses of an extensive sample of plant communities in four habitats of a heterogeneous ecosystem. Sequences of 17 virus operational taxonomic units (OTUs) matched references in the genus, eight had narrow host ranges, and five had wide host ranges. Regardless of host range, the OTU hosts belonged to taxonomically distant families, suggesting no phylogenetic constraints in host use associated with virus adaptation, and that tobamoviruses may be host generalists. The OTUs identified as tobacco mild green mosaic virus (TMGMV), tobacco mosaic virus (TMV), pepper mild mottle virus, and Youcai mosaic virus had the largest realized host ranges that occurred across habitats and exhibited host use unrelated to the degree of human intervention. This result is at odds with assumptions that contact-transmitted viruses would be more abundant in crops than in wild plant communities and could be explained by effective seed-, contact-, or pollinator-mediated transmission or by survival in the soil. TMGMV and TMV had low genetic diversity that was not structured according to habitat or host plant taxonomy, which indicated that phenotypic plasticity allows virus genotypes to infect new hosts with no need for adaptive evolution. Our results underscore the relevance of ecological factors in host range evolution, in addition to the more often studied genetic factors. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
病毒的宿主范围知之甚少，因为研究主要集中在作物和相邻野生植物中的病原病毒上。高通量测序（HTS）避免了偏向导致疾病的植物-病毒相互作用的偏差。在这里，我们使用 HTS 分析了异质生态系统四个生境中广泛的植物群落样本，研究了重要作物病原体烟草花叶病毒的宿主范围。17 个病毒分类单元（OTU）的序列与属中的参考序列匹配，其中 8 个具有狭窄的宿主范围，5 个具有广泛的宿主范围。无论宿主范围如何，OTU 的宿主都属于分类上遥远的科，这表明病毒适应相关的宿主利用没有系统发育限制，并且烟草花叶病毒可能是宿主泛化者。鉴定为烟草轻度绿斑病毒（TMGMV）、烟草花叶病毒（TMV）、辣椒轻度斑驳病毒和 Youcai 花叶病毒的 OTU 具有最大的实际宿主范围，跨越生境并表现出与人类干预程度无关的宿主利用。这一结果与接触传播病毒在作物中比在野生植物群落中更为丰富的假设不一致，可以通过有效的种子、接触或传粉媒介传播或在土壤中存活来解释。TMGMV 和 TMV 的遗传多样性较低，且不受生境或宿主植物分类的结构，这表明表型可塑性允许病毒基因型感染新的宿主，而无需适应进化。我们的研究结果强调了生态因素在宿主范围进化中的相关性，除了更经常研究的遗传因素。
