Antiviral roles of plant ARGONAUTES

Carbonell, Alberto; Carrington, James C.

doi:10.1016/j.pbi.2015.06.013

Cited by 237 publications

(204 citation statements)

References 54 publications

Supporting

Mentioning

188

Contrasting

Unclassified

Order By: Relevance

“…We hypothesized that ABA-mediated resistance is achieved by positive regulation of the RNA-silencing pathway and that such regulation also may affect members of the AGO family because several of these proteins have antiviral properties (Carbonell and Carrington, 2015). To test this, we first examined the promoter regions of AGO genes for the presence of ABREs and MYC and MYB motifs.…”

Section: Callose-deficient Plants Showed Reduced Bamv Levels Upon Trementioning

confidence: 99%

Abscisic Acid Induces Resistance against Bamboo Mosaic Virus through Argonaute2 and 3

Alazem

He²,

Moffett³

et al. 2017

Plant Physiol.

106

View full text Add to dashboard Cite

Plant resistance to pathogens is tuned by defense-related hormones. Of these, abscisic acid (ABA) is well documented to moderate resistance against fungi and bacteria. However, ABA's contribution to resistance against viruses is pleiotropic. ABA affects callose deposition at plasmodesmata (therefore hindering the viral cell-to-cell movement), but here, we show that when callose synthase is down-regulated, ABA still induces resistance against infection with Bamboo mosaic virus (BaMV). By examining the potential connections between the ABA and RNA-silencing pathways in Arabidopsis (Arabidopsis thaliana), we showed that ABA regulates the expression of almost the whole ARGONAUTE (AGO) gene family, of which some are required for plant resistance against BaMV. Our data show that BaMV infection and ABA treatment regulate the same set of AGOs, with positive effects on AGO1, AGO2, and AGO3, no effect on AGO7, and negative effects on AGO4 and AGO10. The BaMV-mediated regulation of AGO1, AGO2, and AGO3 is ABA dependent, because the accumulation of these AGOs in BaMVinfected ABA mutants did not reach the levels observed in infected wild-type plants. In addition, the AGO1-miR168a complex is dispensable for BaMV resistance, while AGO2 and AGO3 were important for ABA-mediated resistance. While most ago mutants showed increased susceptibility to BaMV infection (except ago10), ago1-27 showed reduced BaMV titers, which was attributed to the up-regulated levels of AGO2, AGO3, and AGO4. We have established that ABA regulates the expression of several members of the AGO family, and this regulation partially contributes to ABA-mediated resistance against BaMV. These findings reveal another role for ABA in plants.RNA silencing provides plants with broad resistance against virus infection through small RNA (sRNA)-directed degradation (Ding, 2010). While it is well established that salicylic acid (SA) controls plant resistance to virus infection via R gene resistance (Baebler et al., 2014), it also has been suggested that SA regulates a few genes in the RNA-silencing pathway (Alamillo et al., 2006;Hunter et al., 2013). In fact, the regulation of defense responses has been demonstrated to be a hormonetuned process in many cases. Other hormones, such as jasmonic acid and ethylene, also are involved in the plant-virus interaction but exhibit specificity in terms of the infecting virus and the type of resistance triggered (Alazem and Lin, 2015).Abscisic acid (ABA) also is involved in modulating plant resistance against various pathogens, but the timing of its activation is critical for determining plant susceptibility or resistance; therefore, it has been labeled as a phase-specific modulator of defense responses (MauchMani and Mauch, 2005). Nevertheless, ABA does not seem to be phase specific against viruses, and few reports have shown that ABA improves plant resistance to viruses. We previously found that ABA treatment decreases titers of Bamboo mosaic virus (BaMV) in inoculated leaves of Arabidopsis (Arabidopsis thaliana) and that ABA-me...

show abstract

Section: Callose-deficient Plants Showed Reduced Bamv Levels Upon Trementioning

confidence: 99%

Abscisic Acid Induces Resistance against Bamboo Mosaic Virus through Argonaute2 and 3

Alazem

He²,

Moffett³

et al. 2017

Plant Physiol.

106

View full text Add to dashboard Cite

show abstract

“…The siRNAs are loaded onto Argonaute (AGO) proteins, the effectors of the RNA-Induced Silencing Complex (RISC), to initate slicing or translational repression of target RNAs (Ding and Voinnet, 2007;Carbonell and Carrington, 2015). A family of ten AGO proteins was identified in Arabidopsis thaliana (Vaucheret, 2008), whereas nine AGO homologs were identified in the Nicotiana benthamiana transcriptome (Nakasugi et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

“…benthamiana (Ye et al, 2009) and other RNA viruses (Carbonell and Carrington, 2015). AGO2, AGO5 and AGO7 have also been shown to have a role in antiviral defense (Brosseau and Moffett, 2015;Garcia-Ruiz et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Alfalfa dwarf cytorhabdovirus P protein is a local and systemic RNA silencing supressor which inhibits programmed RISC activity and prevents transitive amplification of RNA silencing

2016

View full text Add to dashboard Cite

Please cite this article as: Bejerman, Nicolás, Mann, Krin S., Dietzgen, Ralf.G., Alfalfa dwarf cytorhabdovirus P protein is a local and systemic RNA silencing supressor which inhibits programmed RISC activity and prevents transitive amplification of RNA silencing.Virus Research http://dx.doi. org/10.1016/j.virusres.2016.08.008 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Highlights  Alfalfa dwarf virus P protein has a weak local RSS activity  Alfalfa dwarf virus P strongly suppresses systemic RNA silencing  Alfalfa dwarf virus P interacts with AGO1 and AGO4  Alfalfa dwarf virus P inhibits miRNA-guided AGO1 cleavage  Alfalfa dwarf virus P prevents the production of secondary siRNAs ABSTRACT Plants employ RNA silencing as an innate defense mechanism against viruses. As a counter-defense, plant viruses have evolved to express RNA silencing suppressor proteins (RSS), which target one or more steps of the silencing pathway. In this study, we show that the phosphoprotein (P) encoded by the negative-sense RNA virus alfalfa dwarf virus (ADV), a species of the genus Cytorhabdovirus, family Rhabdoviridae, is a suppressor of RNA silencing. ADV P has a relatively weak local RSS activity, and does not prevent siRNA accumulation. On the other hand, ADV P strongly suppresses systemic RNA silencing, but does not interfere with the short-distance spread of silencing, which is consistent with its lack of inhibition of siRNA accumulation. The mechanism of suppression appears to involve ADV P binding to RNA-induced silencing complex proteins AGO1 and AGO4 as shown in protein-protein interaction assays when ectopically expressed.In planta, we demonstrate that ADV P likely functions by inhibiting miRNA-guided AGO1cleavage and prevents transitive amplification by repressing the production of secondary siRNAs. As recently described for lettuce necrotic yellows cytorhabdovirus P, but in contrast to other viral RSS known to disrupt AGO activity, ADV P sequence does not contain any recognizable GW/WG or F-box motifs, which suggests that cytorhabdovirus P proteins may use alternative motifs to bind to AGO proteins.

show abstract

“…2). For more detailed information, a collection of excellent, updated reviews describing antiviral RNA silencing mechanisms and suppressors is available (Carbonell and Carrington, 2015;Csorba et al, 2015;Zhang et al, 2015). The diversity in RNAi mechanisms relies mainly on the existence of multiple copies of AGO (Argonaute), RNAdependent RNA polymerase (RDR), DRB (double-stranded RNA binding) and DCL (Dicer-like) genes, which probably result from gene duplication followed by specialization (Parent et al, 2015;Zhang et al, 2015).…”

Section: Rna Silencing Machinery: An Adaptive Antiviral Immunity Mechmentioning

confidence: 99%

“…AGO1, AGO2, AGO4, AGO5, AGO7 and AGO10 have been shown to display antiviral activity in arabidopsis, while AGO1 and AGO18 play antiviral defence roles in rice (reviewed in Carbonell and Carrington, 2015). RDR activities contribute to the amplification of antiviral activity.…”

Section: Rna Silencing Machinery: An Adaptive Antiviral Immunity Mechmentioning

confidence: 99%

Plant immunity against viruses: antiviral immune receptors in focus

Calil

Fontes

2016

Ann Bot

117

125

View full text Add to dashboard Cite

Antiviral roles of plant ARGONAUTES

Cited by 237 publications

References 54 publications

Abscisic Acid Induces Resistance against Bamboo Mosaic Virus through Argonaute2 and 3

Abscisic Acid Induces Resistance against Bamboo Mosaic Virus through Argonaute2 and 3

Alfalfa dwarf cytorhabdovirus P protein is a local and systemic RNA silencing supressor which inhibits programmed RISC activity and prevents transitive amplification of RNA silencing

Plant immunity against viruses: antiviral immune receptors in focus

Contact Info

Product

Resources

About