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ARS Home » Plains Area » Manhattan, Kansas » Center for Grain and Animal Health Research » Hard Winter Wheat Genetics Research » Research » Publications at this Location » Publication #357354
Research Project: Genetic Improvement of Biotic and Abiotic Stress Tolerance and Nutritional Quality in Hard Winter Wheat

Location: Hard Winter Wheat Genetics Research

Title: A single amino acid substitution in the intervening region of 129K protein of cucumber green mottle mosaic virus resulted in attenuated symptoms

Author
item CHEN, HUI - Kansas State University
item INO, MAKOTO - National Institute Of Agrobiological Sciences (NIAS)
item SHIMONO, MASAKI - National Institute Of Agrobiological Sciences (NIAS)
item GANPATRAO, S WAGH - Ehime University
item KOBAYASHI, KAPPEI - Ehime University
item YAENO, TAKASHI - Ehime University
item YAMAOKA, NAOTO - Ehime University
item Bai, Guihua
item NISHIGUCHI, MASAMICHI - Ehime University

Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/25/2019
Publication Date: 11/21/2019
Citation: Chen, H., Ino, M., Shimono, M., Ganpatrao, S., Kobayashi, K., Yaeno, T., Yamaoka, N., Bai, G., Nishiguchi, M. 2019. A single amino acid substitution in the intervening region of 129K protein of cucumber green mottle mosaic virus resulted in attenuated symptoms. Phytopathology. https://doi.org/10.1094/PHYTO-12-18-0478-FI.
DOI: https://doi.org/10.1094/PHYTO-12-18-0478-FI

Interpretive Summary: To protect themselves from viral attack, plants have developed an RNA silencing system against invading viruses. In turn, viruses have developed suppressors of the RNA silencing system to overcome this type of resistance. Our objective was to find the molecular basis for overcoming RNA silencing by the Cucumber green mottle mosaic virus. We compared the RNA silencing suppression activities between an attenuated strain and severe strain of the virus in Nicotiana benthamiana, which is a wild species of tobacco. Protein sequencing analysis found that a single amino acid substitution (glutamic acid to glycine) in the methyltransferase domain and intervening region of a replicase is responsible for the attenuated symptoms. These results may lead to new strategies to improve the resistance to viruses in crop plants.

Technical Abstract: Viral RNA silencing suppressors (VRSs) play a key role in the molecular arms race between host plants and invading viruses. To compare the RNA silencing suppression activities of an attenuated strain (SH33b) and severe strain (SH) of the Cucumber green mottle mosaic virus (CGMMV), we constructed four expression vectors carrying the methyltransferase domain and intervening region (MTIR) of the replicase and 129K protein from both SH and SH33b strains respectively. Using a transgenic green fluorescent protein-silenced (GFP-silenced) line of Nicotiana benthamiana, the level of silencing suppression was investigated by inoculating the silenced N. benthamiana line with the constructed vectors from the SH33b and SH strains. As a result, GFP silencing was interrupted and accumulation of small interfering RNAs (siRNAs) decreased in the SH-infected plants, whereas in the SH33b-infected plants GFP remained silenced. The GFP silencing was suppressed by the MTIR from the SH strain only, not from SH33b strain. Furthermore, analyses of replicase-binding siRNA activity in the SH and SH33b strains using electrophoretic mobility shift assay (EMSA) revealed that a single amino acid substitution (glutamic acid to glycine) in the MTIR of SH33b strain impaired its siRNA binding activity and ability of RNA silencing suppression and eventually led to the attenuated symptoms.