Summary auto-generated
This study developed a novel microprojectile bombardment method to study viral movement proteins and their functional compatibility. Researchers created a potato virus X (PVX) mutant with a defective 25 kDa movement protein (MP) gene by inserting a frameshift mutation, which prevented cell-to-cell viral movement. Using particle bombardment, they simultaneously introduced the defective PVX genome (tagged with a GUS reporter gene) and plasmids expressing movement proteins from other viruses into Nicotiana benthamiana leaf cells. The defective PVX alone produced only tiny, localized blue staining foci indicating no cell-to-cell spread. However, when co-bombarded with expression plasmids containing movement protein genes from PVX, tomato mosaic virus, crucifer tobamovirus, or red clover necrotic mosaic virus, cell-to-cell movement of the defective virus was restored, producing larger staining patterns. Notably, the brome mosaic bromovirus movement protein failed to complement the defect. The results demonstrate that movement proteins from different virus families can functionally substitute for each other in many cases, and establish bombardment-mediated transient complementation as a rapid, quantitative method for analyzing viral movement protein function.
Key findings
- A frameshift mutation in PVX's 25 kDa movement protein gene prevented cell-to-cell viral spread, confining infection to primary inoculated cells
- Movement proteins from unrelated viruses (tobamoviruses, dianthovirus) could functionally complement the defective PVX movement protein, demonstrating cross-viral compatibility
- Brome mosaic bromovirus movement protein failed to complement PVX movement, suggesting functional limitations despite compatibility in other virus combinations
- Microprojectile bombardment enables rapid, quantitative transient complementation experiments for studying viral movement protein function without requiring transgenic plants or helper virus co-infections
This summary was generated automatically from the article PDF and is not part of the original publication. Refer to the PDF for the authoritative text.
Abstract
Microprojectile bombardment was used to examine the transport function of the 25 kDa movement protein (MP) encoded in the triple gene block of potato virus X (PVX). A 25 kDa MP-defective full-length cloned PVX genome carrying a beta-glucuronidase (GUS) reporter gene was co- bombarded with 35S promoter constructs containing either the 25 kDa MP gene of wild-type PVX, the MP gene of either of two tobamoviruses (tomato mosaic virus or crucifer tobamovirus), red clover necrotic mosaic dianthovirus (RCNMV) or brome mosaic bromovirus (BMV). When inoculated alone, the MP-defective PVX was unable to move out of the inoculated cell, as visualized by in situ staining for GUS activity. However, cell-to-cell movement of the mutant PVX genome was restored by co-inoculation with 35S constructs containing the MP cDNA of PVX, either tobamovirus or RCNMV. The BMV MP construct did not complement movement of the defective PVX. These results show that co-bombardment of cDNA of an MP-defective virus with plasmids designed to express MP of other viruses could be used as a fast and simple method for transcomplementation experiments.