Summary auto-generated
This study demonstrates that transgenic potato plants expressing mutated movement protein (MP) genes derived from potato virus X (PVX) develop resistance to multiple plant viruses containing triple gene block (TGB) proteins. Researchers created two mutant 12K MP genes (m12K-Sal and m12K-Kpn) by inserting linkers at specific domains and expressed them in transgenic potato lines. These transgenic plants showed complete resistance to PVX, potato aucuba mosaic potexvirus (PAMV), and carlaviruses potato virus M and S at low inoculum concentrations (3 µg/ml), with resistance decreasing at higher concentrations. Notably, the transgenic plants remained susceptible to potato virus Y, which lacks a TGB protein, suggesting the resistance mechanism is specific to TGB-containing viruses. The authors conclude that resistance results from interference between the modified MP and wild-type viral MP rather than RNA-mediated silencing, as evidenced by the failure of a highly similar mutant (m12K-E) to confer resistance and the broad spectrum of protection against genetically diverse viruses.
Key findings
- Transgenic potato expressing mutant 12K movement proteins (m12K-Sal and m12K-Kpn) shows complete resistance to multiple TGB-containing viruses (PVX, PAMV, PVM, PVS) at low inoculum levels
- Resistance is protein-mediated, not RNA-mediated, demonstrated by failure of nearly identical m12K-E mutant to confer protection despite high sequence similarity
- Protection is specific to TGB-containing viruses; plants remain susceptible to potato virus Y which lacks a TGB protein
- Resistance mechanism involves dominant-negative interference between mutant and wild-type movement proteins that disrupts cell-to-cell and systemic virus spread
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Abstract
Two mutant potato virus X (PVX) movement protein (MP) genes (m 12K-Sal and m 12K-Kpn) were obtained by inserting specific linkers at the boundary between the N-terminal hydrophobic and putative transmembrane segment, and the central invariant hydrophilic region of the respective 12 kDa, 12K, triple gene block (TGB) protein. Several transgenic potato lines which expressed m 12K-Sal or m 12K-Kpn to different degrees were resistant to infection by PVX, potato aucuba mosaic potexvirus and the carlaviruses potato virus M and S over a wide range of inoculum concentrations (3-300 micrograms/ml). However, they were not resistant to potato virus Y, which lacks a TGB protein. We suggest that the resistance of m 12K-Sal and m 12K-Kpn transgenic potato lines is MP- derived and not RNA-mediated.