Department of Plant Pathology, Washington State University, Pullman, WA 99163, USA.
Int J Mol Sci. 2024 Jun 26;25(13):6990. doi: 10.3390/ijms25136990.
Potato mop-top virus (PMTV) is an emerging viral pathogen that causes tuber necrosis in potatoes. PMTV is composed of three single-stranded RNA segments: RNA1 encodes RNA-dependent RNA polymerase, RNA2 contains the coat protein (CP), and RNA3 harbors a triple gene block (TGB 1, TGB2, and TGB3). CP plays a role in viral transmission, while TGB is known to facilitate cell-to-cell and long-distance systemic movement. The role of CP in symptom development, specifically in the presence of TGB genes, was investigated using potato virus X (PVX) as a delivery vehicle to express PMTV genes in the model plant . Plants expressing individual genes showed mild symptoms that included leaf curling and crumpling. Interestingly, symptom severity varied among plants infected with three different combinations: CP with TGB1, CP with TGB2, and CP with TGB3. Notably, the combination of CP and TGB3 induced a hypersensitive response, accompanied by stunted growth and downward curling and crumpling. These results suggest the potential role of TGB co-expressed with CP in symptom development during PMTV infection. Additionally, this study demonstrates the use of the PVX-based expression system as a valuable platform for assessing the role of unknown genes in viral pathogenicity.
马铃薯帚顶病毒（PMTV）是一种新兴的病毒病原体，可导致马铃薯块茎坏死。PMTV 由三条单链 RNA 片段组成：RNA1 编码 RNA 依赖性 RNA 聚合酶，RNA2 包含外壳蛋白（CP），RNA3 则含有三基因块（TGB1、TGB2 和 TGB3）。CP 参与病毒的传播，而 TGB 则被认为有助于细胞间和长距离的系统运动。本研究利用马铃薯 X 病毒（PVX）作为载体，在模式植物中表达 PMTV 基因，研究 CP 在症状发展中的作用，特别是在存在 TGB 基因的情况下。表达单个基因的植物表现出轻微的症状，包括叶片卷曲和皱缩。有趣的是，感染三种不同组合的植物之间的症状严重程度存在差异：CP 与 TGB1、CP 与 TGB2 和 CP 与 TGB3。值得注意的是，CP 与 TGB3 的组合诱导了过敏反应，伴随着生长受阻和向下卷曲和皱缩。这些结果表明，TGB 与 CP 共表达可能在 PMTV 感染过程中对症状发展起作用。此外，本研究还展示了基于 PVX 的表达系统作为评估病毒致病性未知基因作用的有价值平台。
