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ARS Home » Plains Area » Lincoln, Nebraska » Wheat, Sorghum and Forage Research » Research » Publications at this Location » Publication #363790
Research Project: Improved Winter Wheat Disease Resistance and Quality through Molecular Biology, Genetics, and Breeding

Location: Wheat, Sorghum and Forage Research

Title: RNA silencing suppression mechanisms of Triticum mosaic virus P1: dsRNA binding property and mapping functional motifs

Author
item GUPTA, ADARSH - University Of Nebraska
item Tatineni, Satyanarayana - Ts

Submitted to: Virus Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/14/2019
Publication Date: 7/15/2019
Citation: Gupta, A.K., Tatineni, S. 2019. RNA silencing suppression mechanisms of Triticum mosaic virus P1: dsRNA binding property and mapping functional motifs. Virus Research. 269:197640. https://doi.org/10.1016/j.virusres.2019.197640.
DOI: https://doi.org/10.1016/j.virusres.2019.197640

Interpretive Summary: Triticum mosaic virus (TriMV) is an economically important virus infecting wheat in the Great Plains of the USA. Previously, we reported the P1 protein of TriMV suppressed host RNA silencing. This research examined the minimal region of TriMV P1 and its mechanisms in suppressing host RNA silencing and found that the first 55 amino acids are dispensable for suppression of RNA silencing. TriMV P1 targets the host defense mechanisms at multiple steps to successfully establish systemic infection in wheat. This research revealed that the P1 gene of TriMV is a primary target for developing future molecular-based methods for managing this disease. Additionally, TriMV P1 protein can be used to suppress the host RNA silencing for efficient expression of transgenes in wheat.

Technical Abstract: Triticum mosaic virus (TriMV) is the type member of the genus Poacevirus in the family Potyviridae infecting wheat in the Great Plains region of the USA. Previously, we reported that the P1 protein of TriMV as a viral suppressor of RNA silencing. Mutational analyses of P1 show that deletion of 55 N-terminal amino acids and a single amino acid at the C-terminus retained the ability to suppress ssGFP-induced RNA silencing. These data suggest that the N-terminal region but not the C-terminal region of P1 is flexible for suppression of RNA silencing activity. Computational analyses revealed that TriMV P1 contains LXK/RA and zinc finger motifs at the N-terminal region and a domain containing the GW motif at the C-terminal region. Mutational analysis of TriMV P1 suggested functional roles for these motifs in suppression of RNA silencing. Electrophoretic mobility shift assays with bacterially expressed P1 protein revealed that P1 bound to 180-nt and PTGS-like 21- and 24-nt ds-siRNAs derived from green fluorescent protein sequence. Additionally, TriMV P1 protected 655-nt long dsRNA derived from TriMV coat protein from dicing into siRNAs by the human Dicer enzyme. Disruption of GW motif in TriMV P1 through a W332A mutation abolished silencing suppression, pathogenicity enhancement and viability of TriMV, suggesting a functional role for the GW motif in suppression of RNA silencing.