Dataset Information

Unrelated viral suppressors of RNA silencing mediate the control of ARGONAUTE1 level.

ABSTRACT: Various plant viruses ubiquitously mediate the induction of miR168, resulting in the control of ARGONAUTE 1 (AGO1), which is the pivotal component of the microRNA (miRNA) regulation pathway and can also exhibit antiviral function. Here, we demonstrate that miR168-driven control of AGO1 can persist for a long time in virus-infected plants and can be an important component of symptom development. We also show that infection of RNA viruses belonging to various genera is associated with the transcriptional induction of the MIR168 precursor gene. Moreover, in a transient expression study, we reveal that different unrelated viral suppressors of RNA silencing (VSRs) are responsible for the enhanced accumulation of miR168. The induction of miR168 accumulation is an early function of VSRs and this activity is associated with the control of the endogenous AGO1 protein level. The common ability of unrelated VSRs to induce the miR168 level implies that this activity might be a component of the host defence suppression in plant-virus interactions.

SUBMITTER: Varallyay E

PROVIDER: S-EPMC6638692 | biostudies-literature | 2013 Aug

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Unrelated viral suppressors of RNA silencing mediate the control of ARGONAUTE1 level.

Várallyay Eva E Havelda Zoltán Z

Molecular plant pathology 20130411 6

Various plant viruses ubiquitously mediate the induction of miR168, resulting in the control of ARGONAUTE 1 (AGO1), which is the pivotal component of the microRNA (miRNA) regulation pathway and can also exhibit antiviral function. Here, we demonstrate that miR168-driven control of AGO1 can persist for a long time in virus-infected plants and can be an important component of symptom development. We also show that infection of RNA viruses belonging to various genera is associated with the transcri ...[more]

PMID: 23578299

Similar Datasets

Project description:Primary infection of a plant with a pathogen that causes high accumulation of salicylic acid in the plant typically via a hypersensitive response confers enhanced resistance against secondary infection with a broad spectrum of pathogens, including viruses. This phenomenon is called systemic acquired resistance (SAR), which is a plant priming for adaption to repeated biotic stress. However, the molecular mechanisms of SAR-mediated enhanced inhibition, especially of virus infection, remain unclear. Here, we show that SAR against cucumber mosaic virus (CMV) in tobacco plants (Nicotiana tabacum) involves a calmodulin-like protein, rgs-CaM. We previously reported the antiviral function of rgs-CaM, which binds to and directs degradation of viral RNA silencing suppressors (RSSs), including CMV 2b, via autophagy. We found that rgs-CaM-mediated immunity is ineffective against CMV infection in normally growing tobacco plants but is activated as a result of SAR induction via salicylic acid signaling. We then analyzed the effect of overexpression of rgs-CaM on salicylic acid signaling. Overexpressed and ectopically expressed rgs-CaM induced defense reactions, including cell death, generation of reactive oxygen species, and salicylic acid signaling. Further analysis using a combination of the salicylic acid analogue benzo-(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH) and the Ca2+ ionophore A23187 revealed that rgs-CaM functions as an immune receptor that induces salicylic acid signaling by simultaneously perceiving both viral RSS and Ca2+ influx as infection cues, implying its autoactivation. Thus, secondary infection of SAR-induced tobacco plants with CMV seems to be effectively inhibited through 2b recognition and degradation by rgs-CaM, leading to reinforcement of antiviral RNA silencing and other salicylic acid-mediated antiviral responses.IMPORTANCE Even without an acquired immune system like that in vertebrates, plants show enhanced whole-plant resistance against secondary infection with pathogens; this so-called systemic acquired resistance (SAR) has been known for more than half a century and continues to be extensively studied. SAR-induced plants strongly and rapidly express a number of antibiotics and pathogenesis-related proteins targeted against secondary infection, which can account for enhanced resistance against bacterial and fungal pathogens but are not thought to control viral infection. This study showed that enhanced resistance against cucumber mosaic virus is caused by a tobacco calmodulin-like protein, rgs-CaM, which detects and counteracts the major viral virulence factor (RNA silencing suppressor) after SAR induction. rgs-CaM-mediated SAR illustrates the growth versus defense trade-off in plants, as it targets the major virulence factor only under specific biotic stress conditions, thus avoiding the cost of constitutive activation while reducing the damage from virus infection.

Dataset Information

Unrelated viral suppressors of RNA silencing mediate the control of ARGONAUTE1 level.

Publications

Unrelated viral suppressors of RNA silencing mediate the control of ARGONAUTE1 level.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets