Isolation, expression and functional analysis of a putative RNA-dependent RNA polymerase gene from maize (Zea mays L.)

He, Junguang; Zhao, Dong; Jia, Zhiwei; Wang, Jianhua; Wang, Guoying

doi:10.1007/s11033-009-9692-2

Cited by 25 publications

(25 citation statements)

References 40 publications

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“…The expression of the key factors of RNA-silencing pathways usually is activated by virus infection at the transcriptional level to increase the activities of antiviral RNA silencing. For example, the expression of AGO1, AGO2, or RDR1 was usually induced by infection with diverse viruses (Yang et al, 2004;Alamillo et al, 2006;Zhang et al, 2006;Azevedo et al, 2010;He et al, 2010;Satoh et al, 2010;Várallyay et al, 2010;Du et al, 2011;Harvey et al, 2011). However, the molecular mechanisms of activation of the expression of these antiviral genes are unknown.…”

Section: Mir444-regulated Nitrate Signaling May Play Roles In the Ricmentioning

confidence: 99%

“…RDR1 orthologs have been reported to be virus or salicylic acid inducible in different plants, including Arabidopsis, Nicotiana spp., Medicago truncatula, maize (Zea mays), and rice (Oryza sativa; Yang et al, 2004;Alamillo et al, 2006;He et al, 2010;Satoh et al, 2010;Du et al, 2011), and to provide basal resistance to several viruses by participating in the biogenesis of virusderived secondary siRNAs (Diaz-Pendon et al, 2007;Qi et al, 2009;Garcia-Ruiz et al, 2010;Wang et al, 2010). Recently, it was reported that RDR1 also is responsible for the production of a distinct class of virus-activated siRNAs, which direct widespread silencing of host genes to confer broad-spectrum antiviral activity in Arabidopsis (Cao et al, 2014), indicating that RDR1 plays a key role in antiviral resistance by silencing both the viral RNAs and the host immunity-related genes.…”

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confidence: 99%

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A Signaling Cascade from miR444 to RDR1 in Rice Antiviral RNA Silencing Pathway

et al. 2016

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Plant RNA-DEPENDENT RNA POLYMERASE1 (RDR1) is a key component of the antiviral RNA-silencing pathway, contributing to the biogenesis of virus-derived small interfering RNAs. This enzyme also is responsible for producing virusactivated endogenous small interfering RNAs to stimulate the broad-spectrum antiviral activity through silencing host genes. The expression of RDR1 orthologs in various plants is usually induced by virus infection. However, the molecular mechanisms of activation of RDR1 expression in response to virus infection remain unknown. Here, we show that a monocot-specific microRNA, miR444, is a key factor in relaying the antiviral signaling from virus infection to OsRDR1 expression. The expression of miR444 is enhanced by infection with Rice stripe virus (RSV), and overexpression of miR444 improves rice (Oryza sativa) resistance against RSV infection accompanied by the up-regulation of OsRDR1 expression. We further show that three miR444 targets, the MIKC C -type MADS box proteins OsMADS23, OsMADS27a, and OsMADS57, form homodimers and heterodimers between them to repress the expression of OsRDR1 by directly binding to the CArG motifs of its promoter. Consequently, an increased level of miR444 diminishes the repressive roles of OsMADS23, OsMADS27a, and OsMADS57 on OsRDR1 transcription, thus activating the OsRDR1-dependent antiviral RNA-silencing pathway. We also show that overexpression of miR444-resistant OsMADS57 reduced OsRDR1 expression and rice resistance against RSV infection, and knockout of OsRDR1 reduced rice resistance against RSV infection. In conclusion, our results reveal a molecular cascade in the rice antiviral pathway in which miR444 and its MADS box targets directly control OsRDR1 transcription.RNA silencing mediated by regulatory small RNAs (microRNAs [miRNAs] and small interfering RNAs [siRNAs]) negatively regulates gene expression at the posttranscriptional level or at the transcriptional level in eukaryotic organisms. Besides small RNAs, plant RNA-silencing pathways incorporate several kinds of core protein components, such as DICER-LIKE (DCL) RNase III endonucleases, which process long doublestranded RNA (dsRNA) into small RNA duplexes; ARGONAUTEs (AGOs), the major effector of the RNA-induced silencing complexes, which bind to small RNAs for silencing target RNAs; and RNA-dependent RNA polymerases (RDRs), which are required for copying single-stranded RNAs into dsRNAs for downstream processing by DCLs. Multiple DCLs, AGOs, and RDRs have evolved in plants and thus form an array of RNA-silencing pathways (Axtell, 2013;Martínez de Alba et al., 2013;Bologna and Voinnet, 2014). Among them, the antiviral RNA-silencing pathway is the earliest described and most extensively studied. It is well known that the antiviral silencing pathway directly targets viral RNAs. Briefly, as in Arabidopsis (Arabidopsis thaliana), the stem-loop structures and dsRNA replication intermediates of viral RNAs are recognized and cleaved by DCLs (DCL4 and DCL2) to produce primary virus-derived small interferi...

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Section: Mir444-regulated Nitrate Signaling May Play Roles In the Ricmentioning

confidence: 99%

mentioning

confidence: 99%

A Signaling Cascade from miR444 to RDR1 in Rice Antiviral RNA Silencing Pathway

et al. 2016

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“…Our previous studies showed that SCMV was the major causal agent of maize dwarf mosaic disease in China, and the Beijing isolate (SCMV-BJ) belonged to the prevalent strain [46]. It was reported that SCMV infection could elicit the accumulation of RDR1 mRNA, and silenced RDR1 maize plants were more susceptible to SCMV infection [47]. Co-expression assay demonstrated that the HC-Pro encoded by SCMV suppressed the RNA silencing induced by sense RNA and dsRNA, and down-regulated the accumulation of RDR6 mRNA [48].…”

Section: Introductionmentioning

confidence: 99%

Characterization of Small Interfering RNAs Derived from Sugarcane Mosaic Virus in Infected Maize Plants by Deep Sequencing

Xia

Peng

et al. 2014

PLoS ONE

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RNA silencing is a conserved surveillance mechanism against viruses in plants. It is mediated by Dicer-like (DCL) proteins producing small interfering RNAs (siRNAs), which guide specific Argonaute (AGO)-containing complexes to inactivate viral genomes and may promote the silencing of host mRNAs. In this study, we obtained the profile of virus-derived siRNAs (vsiRNAs) from Sugarcane mosaic virus (SCMV) in infected maize (Zea mays L.) plants by deep sequencing. Our data showed that vsiRNAs which derived almost equally from sense and antisense SCMV RNA strands accumulated preferentially as 21- and 22-nucleotide (nt) species and had an adenosine bias at the 5′-terminus. The single-nucleotide resolution maps revealed that vsiRNAs were almost continuously but heterogeneously distributed throughout the SCMV genome and the hotspots of sense and antisense strands were mainly distributed in the HC-Pro coding region. Moreover, dozens of host transcripts targeted by vsiRNAs were predicted, several of which encode putative proteins involved in ribosome biogenesis and in biotic and abiotic stresses. We also found that ZmDCL2 mRNAs were up-regulated in SCMV-infected maize plants, which may be the cause of abundant 22-nt vsiRNAs production. However, ZmDCL4 mRNAs were down-regulated slightly regardless of the most abundant 21-nt vsiRNAs. Our results also showed that SCMV infection induced the accumulation of AGO2 mRNAs, which may indicate a role for AGO2 in antiviral defense. To our knowledge, this is the first report on vsiRNAs in maize plants.

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“…For that reason, RDR1, RDR2, and RDR6/SGS2/SDE1 have been highlighted as very important and crucial factors in antiviral plant defense responses in different plant species (Mourrain et al, 2000; Yu et al, 2003; Muangsan et al, 2004; Yang et al, 2004; Qu et al, 2005, 2008; Schwach et al, 2005; Adenot et al, 2006; Diaz-Pendon et al, 2007; Donaire et al, 2008; Garcia-Ruiz et al, 2010; He et al, 2010; Wang et al, 2010, 2011b). Although in certain cases, some RDRs mutants have no effects on the susceptibility to viruses carrying VSRs (Diaz-Pendon et al, 2007; Donaire et al, 2008).…”

Section: Antiviral and Antibacterial Roles Of The Small Rna Biogenesimentioning

confidence: 99%

Small RNAs in plant defense responses during viral and bacterial interactions: similarities and differences

Peláez¹,

Sánchez²

2013

Front. Plant Sci.

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Small non-coding RNAs constitute an important class of gene expression regulators that control different biological processes in most eukaryotes. In plants, several small RNA (sRNA) silencing pathways have evolved to produce a wide range of small RNAs with specialized functions. Evidence for the diverse mode of action of the small RNA pathways has been highlighted during plant–microbe interactions. Host sRNAs and small RNA silencing pathways have been recognized as essential components of plant immunity. One way plants respond and defend against pathogen infections is through the small RNA silencing immune system. To deal with plant defense responses, pathogens have evolved sophisticated mechanisms to avoid and counterattack this defense strategy. The relevance of the small RNA-mediated plant defense responses during viral infections has been well-established. Recent evidence points out its importance also during plant–bacteria interactions. Herein, this review discusses recent findings, similarities and differences about the small RNA-mediated arms race between plants and these two groups of microbes, including the small RNA silencing pathway components that contribute to plant immune responses, the pathogen-responsive endogenous sRNAs and the pathogen-delivered effector proteins.

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Isolation, expression and functional analysis of a putative RNA-dependent RNA polymerase gene from maize (Zea mays L.)

Cited by 25 publications

References 40 publications

A Signaling Cascade from miR444 to RDR1 in Rice Antiviral RNA Silencing Pathway

A Signaling Cascade from miR444 to RDR1 in Rice Antiviral RNA Silencing Pathway

Characterization of Small Interfering RNAs Derived from Sugarcane Mosaic Virus in Infected Maize Plants by Deep Sequencing

Small RNAs in plant defense responses during viral and bacterial interactions: similarities and differences

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