中文摘要：感染复数（MOI），即感染细胞的病毒基因组数量，是病毒进化的一个重要参数，每个病毒和环境的感染复数都可能会有一个最大限度提高病毒适应性的最佳值。因此，MOI可能会由病毒功能控制，这是真核生物感染病毒中未经充分研究论证的一个假设。为了分析MOI是否由病毒功能所控制，本文研究评估了被番茄丛矮病毒（TBSV）的两个遗传变异体，或者TBSV与TBSV衍生的缺损干扰RNA（DI-RNA），或者TBSV与建兰环斑病毒（CymRSV）共同侵染的植物的MOI。 研究结果表明：MOI是一个数量性状，呈连续变异，因此MOI是由不同因素综合决定的，包括不同病毒编码的功能。
外文摘要：The multiplicity of infection (MOI), i.e., the number of viral genomes that infect a cell, is an important parameter in virus evolution, which for each virus and environment may have an optimum value that maximizes virus fitness. Thus, the MOI might be controlled by virus functions, an underexplored hypothesis in eukaryote-infecting viruses. To analyze if the MOI is controlled by virus functions, we estimated the MOI in plants coinfected by two genetic variants of Tomato bushy stunt virus (TBSV); by TBSV and a TBSV-derived defective interfering RNA (DI-RNA); or by TBSV and a second tombusvirus, Cymbidium ringspot virus (CymRSV). The MOI was significantly larger in TBSV-CymRSV coinfections (similar to 4.0) than in TBSV-TBSV or TBSV-DI-RNA coinfections (similar to 1.7 to 2.2). Coinfections by CymRSV or TBSV with chimeras in which an open reading frame (ORF) of one virus species was replaced by that of the other identified a role of viral proteins in determining the MOI, which ranged from 1.6 to 3.9 depending on the coinfecting genotypes. However, no virus-encoded protein or genomic region was the sole MOI determinant. Coinfections by CymRSV and TBSV mutants in which the expression of the gene-silencing suppressor protein p19 was abolished also showed a possible role of gene silencing in MOI determination. Taken together, these results demonstrate that the MOI is a quantitative trait showing continuous variation and that as such it has a complex determination involving different virus-encoded functions. IMPORTANCE: The number of viral genomes infecting a cell, or the multiplicity of infection (MOI), is an important parameter in virus evolution affecting recombination rates, selection intensity on viral genes, evolution of multipartite genomes, or hyperparasitism by satellites or defective interfering particles. For each virus and environment, the MOI may have an optimum value that maximizes virus fitness, but little is known about MOI control in eukaryote-infecting viruses. We show here that in plants coinfected by two genotypes of Tomato bushy stunt virus (TBSV), the MOI was lower than in plants coinfected by TBSV and Cymbidium ringspot virus (CymRSV). Coinfections by CymRSV or TBSV with TBSV-CymRSV chimeras showed a role of viral proteins in MOI determination. Coinfections by CymRSV and TBSV mutants not expressing the gene-silencing suppressor protein also showed a role of gene silencing in MOI determination. The results demonstrate that the MOI is a quantitative trait with a complex determination involving different viral functions.
作者：Livia Donairea;József Burgyánb and Fernando García-Arenala;A. Simon, Editor
作者单位：马德里理工大学
期刊名称：Journal of Virology
期刊影响因子：4.606
出版年份：2016
出版刊次：1
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