Vance V B
Department of Biological Sciences, University of South Carolina, Columbia 29208.
Virology. 1991 Jun;182(2):486-94. doi: 10.1016/0042-6822(91)90589-4.
Potato virus X (PVX) and potato virus Y (PVY) may coinfect tobacco to cause a classic synergistic disease. In the acute stage the disease is characterized by a dramatic increase in the accumulation of infectious PVX particles, with no corresponding increase or decrease in the accumulation of PVY. The accumulation of PVX genomic RNA and coat protein has been examined in doubly versus singly infected tobacco leaves. These experiments indicate that the levels of both viral components increase in doubly infected plants to about the same extent as the level of infectious PVX particles. The level of PVX subgenomic coat protein mRNA found associated with polyribosomes of synergistically infected plants is also increased to a similar extent. Pulse labelling experiments suggest that the increase in PVX coat protein is due to an increased rate of synthesis. The level of PVX (-) strand RNA template increases disproportionately in doubly infected tissue, to a level three times higher than that of the virion or its component parts. This result suggests that PVX/PVY synergism involves an alteration in the normal regulation of the relative levels of PVX (+) and (-) strand RNAs during viral replication.
马铃薯X病毒（PVX）和马铃薯Y病毒（PVY）可能共同感染烟草，引发典型的协同病害。在急性期，该病的特征是感染性PVX颗粒的积累急剧增加，而PVY的积累没有相应增加或减少。已对双重感染与单一感染的烟草叶片中PVX基因组RNA和外壳蛋白的积累进行了检测。这些实验表明，在双重感染的植株中，两种病毒成分的水平增加幅度与感染性PVX颗粒的水平大致相同。在协同感染植株的多核糖体上发现的PVX亚基因组外壳蛋白mRNA水平也有类似程度的增加。脉冲标记实验表明，PVX外壳蛋白的增加是由于合成速率提高。在双重感染的组织中，PVX（-）链RNA模板水平不成比例地增加，达到比病毒粒子或其组成部分高三倍的水平。这一结果表明，PVX/PVY协同作用涉及病毒复制过程中PVX（+）和（-）链RNA相对水平正常调控的改变。
