Díaz-Pendón Juan A, Ding Shou-Wei
Center for Plant Cell Biology, Department of Plant Pathology and Microbiology, University of California, Riverside, California 92521, USA.
Annu Rev Phytopathol. 2008;46:303-26. doi: 10.1146/annurev.phyto.46.081407.104746.
Plant and animal viruses overcome host antiviral silencing by encoding diverse viral suppressors of RNA silencing (VSRs). Prior to the identification and characterization of their silencing suppression activities mostly in transgene silencing assays, plant VSRs were known to enhance virus accumulation in the inoculated protoplasts, promote cell-to-cell virus movement in the inoculated leaves, facilitate the phloem-dependent long-distance virus spread, and/or intensify disease symptoms in systemically infected tissues. Here we discuss how the various silencing suppression activities of VSRs may facilitate these distinct steps during plant infection and why VSRs may not play a direct role in eliciting disease symptoms by general impairments of host endogenous small RNA pathways. We also highlight many of the key questions still to be addressed on the role of viral suppression of antiviral silencing in plant infection.
植物和动物病毒通过编码多种RNA沉默病毒抑制子（VSRs）来克服宿主的抗病毒沉默。在主要通过转基因沉默试验鉴定和表征其沉默抑制活性之前，人们就已知道植物VSRs能增强病毒在接种原生质体中的积累，促进病毒在接种叶片中的细胞间移动，推动韧皮部依赖的病毒长距离传播，和/或加剧系统感染组织中的病害症状。在此，我们讨论VSRs的各种沉默抑制活性如何在植物感染过程中促进这些不同步骤，以及为何VSRs可能不会通过普遍损害宿主内源性小RNA途径在引发病害症状中发挥直接作用。我们还强调了关于病毒对抗病毒沉默的抑制在植物感染中的作用仍有待解决的许多关键问题。
