Citation: Yang, N.; Qiu, Y.; Shen, Y.; Xu, K.; Yin, J. Genome-Wide Analysis of Soybean Mosaic Virus Reveals Diverse Mechanisms in Parasite-Derived Resistance. Agronomy 2024, 14, 1457. https:// doi.org/10.3390/agronomy14071457
Keywords: virus resistance; potyvirus; RNA silencing; plant protection
Abstract
Plant viruses cause severe losses in agricultural production. Parasite-derived resistance (PDR) offers a promising avenue for developing disease-resistant varieties independent of resistance genes. However, for potyviruses with great agricultural importance, such as soybean mosaic virus (SMV), systematic research on viral genes that can be used for PDR has not been conducted. In this study, we transiently expressed the untranslated region (UTR) or each protein-coding cistron of SMV in Nicotiana benthamiana to evaluate their potential role in conferring PDR. A viral suppressor of RNA silencing (VSR) was also applied to investigate the possible mechanisms of the PDR. The results showed that the transient overexpression of UTR and each cistron of SMV could inhibit SMV infection. The expression of VSR in N. benthamiana leaves could compromise UTR and most of the SMV cistron-mediated inhibition of SMV infection, indicating the involvement of RNA silencing in PDR. In comparison, the expression of VSR could not compromise the PDR conferred by coat protein (CP), P3N-PIPO, cylindrical inclusion (CI), and NIa-Pro, suggesting that these viral cistrons may play roles in PDR at the protein level. These results reveal diverse mechanisms in PDR conferred by different viral cistrons and provide potential gene candidates that can be used for transgenic approaches against SMV.
Photograph and Microscopy
For assessment of the viral infection in the leaves, the GFP and RFP signals were excited using a handheld fluorescent protein lamp LUYOR-3415RG (Luyor Instrument Co., Ltd.). Subsequently, the fluorescence emitted by GFP and RFP was captured using an LP510 filter or a BP590 filter (LUV-590A, Shanghai Luyor Instrument Co., Ltd.), respectively, with a digital camera. In order to overlay images of the leaves with different fluorescence, Photoshop CC (version 14.0) was used to extract the RGB signals of fluorescent proteins.
The GFP expression in the following figures was captured under a handheld fluorescent protein lamp LUYOR-3415RG.
