1. Tobacco calmodulin-like protein provides secondary defense by binding to and directing degradation of virus RNA silencing suppressors.
- Author
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Nakahara, Kenji S., Masuta, Chikara, Yamada, Syouta, Shimura, Hanako, Kashihara, Yukiko, Wada, Tomoko S., Meguro, Ayano, Goto, Kazunori, Tadamura, Kazuki, Sueda, Kae, Sekiguchi, Tom, Shao, Jun, Itchoda, Noriko, Matsumura, Takeshi, Igarashi, Manabu, Ito, Kimihito, Carthew, Richard W., and Uyeda, Ichiro
- Subjects
TOBACCO ,PLANT proteins ,PLANT defenses ,PLANT gene silencing ,DOUBLE-stranded RNA ,ANTIVIRAL agents ,PROTEASOMES - Abstract
RNA silencing (RNAI) induced by virus-derived double-stranded RNA (dsRNA), which is in a sense regarded as a pathogen-associated molecular pattern (PAMP) of viruses, is a general plant defense mechanism. To counteract this defense, plant viruses express RNA silencing suppressors (RSSs), many of which bind to dsRNA and attenuate RNAi. We showed that the tobacco calmodulin-like protein, rgs-CaM, counterattacked viral RSSs by binding to their dsRNA-binding domains and sequestering them from inhibiting RNAi. Autophagy-like protein degradation seemed to operate to degrade RSSs with the sacrifice of rgs-CaM. These RSSs could thus be regarded as secondary viral PAMPs. This study uncovered a unique defense system in which an rgs-CaM-mediated countermeasure against viral RSSs enhanced host antiviral RNAi in tobacco. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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