Virology Lab, Centre of Agricultural Biochemistry and Biotechnology, University of Agriculture, Faisalabad 38000, Pakistan; Agricultural Biotechnology Division, National Institute for Biotechnology and Genetic Engineering, Jhang Road, Faisalabad, Pakistan.
Agricultural Biotechnology Division, National Institute for Biotechnology and Genetic Engineering, Jhang Road, Faisalabad, Pakistan.
Gene. 2019 Feb 20;686:43-48. doi: 10.1016/j.gene.2018.11.002. Epub 2018 Nov 3.
Papaya leaf curl virus (PaLCuV) is a begomovirus (genus Begomovirus; family Geminiviridae) with a monopartite genome that is usually associated with beta- and alphasatellites in plants. Geminiviruses are DNA viruses with small circular genomes that occur as minichromosomes in the nucleus and are susceptible to post-transcriptional gene silencing (PTGS) and transcriptional gene silencing (TGS). Transient expression of the PaLCuV V2 (PV2) protein together with the green fluorescent protein (GFP) in Nicotiana benthamiana resulted in enhanced levels of GFP fluorescence and GFP mRNA, indicative of suppression of PTGS. Expression of PV2 from a Potato virus X vector restored GFP expression in N. benthamiana plants harbouring a transcriptionally silenced GFP transgene, indicative of suppression of TGS. The results show that the PV2 protein encoded by PaLCuV has both suppressor of PTGS and TGS activity and is an important factor in overcoming host RNA-silencing based defenses.
番木瓜曲叶病毒（PaLCuV）是一种伴随β-和α卫星的单分体基因组单链 DNA 病毒（属：双生病毒科；家族：双生病毒科）。双生病毒的基因组很小，呈环状，以微染色体的形式存在于细胞核中，易发生转录后基因沉默（PTGS）和转录基因沉默（TGS）。在本氏烟中瞬时表达 PaLCuV 的 V2（PV2）蛋白和绿色荧光蛋白（GFP），导致 GFP 荧光和 GFPmRNA 水平增强，表明 PTGS 受到抑制。马铃薯 X 病毒载体表达 PV2 可恢复转录沉默 GFP 转基因本氏烟植株中 GFP 的表达，表明 TGS 受到抑制。结果表明，PaLCuV 编码的 PV2 蛋白具有 PTGS 和 TGS 活性的抑制子，是克服基于宿主 RNA 沉默防御的重要因素。
