Mol Plant Microbe Interact. 2013 Oct;26(10):1211-24. doi: 10.1094/MPMI-04-13-0093-R.
Plum pox virus (PPV)-D and PPV-R are two isolates from strain D of PPV that differ in host specificity. Previous analyses of chimeras originating from PPV-R and PPV-D suggested that the N terminus of the coat protein (CP) includes host-specific pathogenicity determinants. Here, these determinants were mapped precisely by analyzing the infectivity in herbaceous and woody species of chimeras containing a fragment of the 3' region of PPV-D (including the region coding for the CP) in a PPV-R backbone. These chimeras were not infectious in Prunus persica, but systemically infected Nicotiana clevelandii and N. benthamiana when specific amino acids were modified or deleted in a short 30-amino-acid region of the N terminus of the CP. Most of these mutations did not reduce PPV fitness in Prunus spp. although others impaired systemic infection in this host. We propose a model in which the N terminus of the CP, highly relevant for virus systemic movement, is targeted by a host defense mechanism in Nicotiana spp. Mutations in this short region allow PPV to overcome the defense response in this host but can compromise the efficiency of PPV systemic movement in other hosts such as Prunus spp.
李痘病毒（PPV）-D 和 PPV-R 是两种来自 PPV-D 株的分离物，它们在宿主特异性上有所不同。先前对源自 PPV-R 和 PPV-D 的嵌合体的分析表明，外壳蛋白（CP）的 N 端包含宿主特异性致病性决定因素。在这里，通过分析含有 PPV-D 的 3' 区片段（包括 CP 编码区）的嵌合体在 PPV-R 骨架中的感染力，精确地绘制了这些决定因素的图谱。这些嵌合体在桃中没有感染性，但当 CP 的 N 端的一个短 30 个氨基酸区域中的特定氨基酸被修饰或删除时，它们可以系统地感染烟草和本氏烟。这些突变中的大多数并没有降低 PPV 在桃中的适应性，尽管其他突变会损害该宿主中的系统感染。我们提出了一个模型，即 CP 的 N 端，与病毒的系统运动高度相关，是烟草中宿主防御机制的靶标。该短区域中的突变使 PPV 能够克服该宿主中的防御反应，但可能会损害 PPV 在其他宿主（如桃）中的系统运动效率。
