Location: Sugarbeet Research
Title: Suppressing Tymovirus replication using a variant of ubiquitinAuthor
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DE SILVA, ANURADHA - University Of Manitoba |
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KIM, KIHUN - University Of Manitoba |
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WEILAND, JOHN - US Department Of Agriculture (USDA) |
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HWANG, JIHYUN - University Of Manitoba |
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CHUNG, JACKY - University Of Waterloo |
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PATEL, TRUSHAR - University Of Lethbridge |
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PATEL, ANKOOR - University Of Manitoba |
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MIRA, MOHOMMED M. - University Of Manitoba |
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KHAJEHPOUR, MAZDAK - University Of Manitoba |
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Bolton, Melvin |
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STASOLLA, CLAUDIO - University Of Manitoba |
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SIDHU, SACHDEV - University Of Waterloo |
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MARK, BRIAN L - University Of Manitoba |
Submitted to: PLoS Pathogens
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 1/22/2025 Publication Date: N/A Citation: N/A Interpretive Summary: RNA viruses have evolved numerous strategies to overcome host resistance, including the use of multi-functional proteins that are not only critical for virus replication, but also manipulate plant resistance mechanisms that enable the virus to cause disease. Here, we report an approach to suppress the ability of the virus to target plant resistance mechanisms using transgenic plants whereby the plant produces a "decoy" that effectively inactivates a viral protein, which reduces the ability of the virus to replicate in the plant. Our results demonstrate the potential of this strategy to reduce disease caused by an important group of virus pathogens worldwide. Technical Abstract: RNA viruses have evolved numerous strategies to overcome host resistance and immunity, including the use of multifunctional proteases that not only cleave viral polyproteins during virus replication but also deubiquitinate cellular proteins to suppress ubiquitin (Ub)-mediated antiviral mechanisms. Here, we report an approach to suppress the polyprotein cleavage and deubiquitinase (DUB) activity of the protease (PRO) from Turnip Yellow Mosaic Virus (TYMV) to attenuate its infection of Arabidopsis thaliana. Panning a library of phage-displayed Ub variants (UbVs) with recombinant PRO yielded several UbVs that bound the viral protease with nanomolar affinities and blocked its function. The tightest binding UbV (UbV3) had an EC50 of 0.3nM and was found to inhibit both polyprotein cleavage and DUB activity of PRO in vitro. X-ray structures of UbV3 in isolation and in complex with PRO revealed that the UbV3 inhibitor exists as a dimer that binds two copies of PRO. Consistent with our biochemical and structural findings, transgenic expression of UbV3 in the cytosol of A. thaliana suppressed TYMV replication in planta, with the reduction in virus titers being inversely correlated to UbV3 expression level. Our results demonstrate the potential of using UbVs to protect plants from tymovirus infection, a family of viruses that contain numerous members of significant agricultural concern, along with other tymovirus-like viruses encoding the PRO domain homolog. |