The Three Essential Motifs in P0 for Suppression of RNA Silencing Activity of Potato leafroll virus Are Required for Virus Systemic Infection

Rashid, Mamun-Or; Zhang, Xiaoyan; Wang, Ying; Li, Dawei; Yu, Jialin; Han, Chenggui

doi:10.3390/v11020170

Cited by 12 publications

(17 citation statements)

References 44 publications

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“…At 5 dpi, GFP fluorescence showed that the LP mutant did not affect its VSR activity; however, the LPP mutant abolished its VSR activity ( Figure 3 C). These results were consistent with a previous observation for enamovirus pea enation mosaic virus-1 P0, where substitution of the conserved LP residues did not affect the suppressor activity while substitution of the conserved LPP residues inhibited its suppressor activity [ 55 ]. Western blot analyses showed that GFP protein accumulation was consistent with fluorescence levels ( Figure 3 D).…”

Section: Resultssupporting

confidence: 93%

Functional Characterization of RNA Silencing Suppressor P0 from Pea Mild Chlorosis Virus

Qi-zhong

Zhuo

Zhao

et al. 2020

IJMS

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To counteract host antiviral RNA silencing, plant viruses encode numerous viral suppressors of RNA silencing (VSRs). P0 proteins have been identified as VSRs in many poleroviruses. However, their suppressor function has not been fully characterized. Here, we investigated the function of P0 from pea mild chlorosis virus (PMCV) in the suppression of local and systemic RNA silencing via green fluorescent protein (GFP) co-infiltration assays in wild-type and GFP-transgenic Nicotiana benthamiana (line 16c). Amino acid deletion analysis showed that N-terminal residues Asn 2 and Val 3, but not the C-terminus residues from 230–270 aa, were necessary for PMCV P0 (P0PM) VSR activity. P0PM acted as an F-box protein, and triple LPP mutation (62LPxx79P) at the F-box-like motif abolished its VSR activity. In addition, P0PM failed to interact with S-phase kinase-associated protein 1 (SKP1), which was consistent with previous findings of P0 from potato leafroll virus. These data further support the notion that VSR activity of P0 is independent of P0–SKP1 interaction. Furthermore, we examined the effect of P0PM on ARGONAUTE1 (AGO1) protein stability, and co-expression analysis showed that P0PM triggered AGO1 degradation. Taken together, our findings suggest that P0PM promotes degradation of AGO1 to suppress RNA silencing independent of SKP1 interaction.

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Section: Resultssupporting

confidence: 93%

Functional Characterization of RNA Silencing Suppressor P0 from Pea Mild Chlorosis Virus

Qi-zhong

Zhuo

Zhao

et al. 2020

IJMS

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“…Furthermore, the replacement of W140A in the G139/W140/ G141-like motif weakened P0 activity (Zhuo et al, 2014). Recently, Rashid et al (2019) confirmed these findings for a Canadian P0 PL and revealed that the VSR-defective mutants in the F-box-like motif, the G139/W140/G141-like motif, and in the C-terminus of P0 (F220) affected not only virus accumulation but also its systemic movement.…”

mentioning

confidence: 65%

“…With these results, Rashid et al (2019) demonstrated that P0 is required for PLRV accumulation and systemic infection.…”

mentioning

confidence: 75%

“…The silencing-suppressor activity described for the P0 protein of PLRV (P0 PL ) varies among different PLRV isolates. So far, P0 PL proteins of isolates from Europe, Inner Mongolia, Australia, and Canada have been shown to have RNA silencing suppressor activity, with different suppression intensities at the local level (Pazhouhandeh, 2007;Fusaro et al, 2012;Zhuo et al, 2014;Rashid et al, 2019). Moreover, P0 PL proteins of isolates showed differences regarding their interaction with E3 SCF ubiquitin ligase complexes.…”

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confidence: 99%

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Argentinian potato leafroll virus P0 protein: Novel activities for a previously known suppressor

et al. 2020

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The potato leafroll virus (PLRV) P0 protein (P0PL) is a suppressor of RNA silencing. In this study, we showed that P0 protein from an Argentinian isolate of PLRV (P0PL‐Ar) has an additional activity not described for other PLRV or P0 proteins from poleroviruses. Besides reporting that P0PL‐Ar displays both local and systemic silencing suppressor activity, we demonstrated, for the first time, that P0PL‐Ar impedes accumulation of dsRNA‐derived siRNAs. We also showed that P0PL‐Ar interacts with Solanum tuberosum SKP1 orthologue (StSKP1) and triggers destabilization of ARGONAUTE 1 (AGO1) and that these actions are mediated by the F‐box‐like domain. A mutant in the GW/WG motif within the P0PL‐Ar F‐box‐like motif lost the suppression activity, the interaction with StSKP1 and abolished AGO1 decay. Interestingly, a mutant in the L76/P77 residues within the P0PL‐Ar F‐box‐like motif, which lost the suppression activity and the interaction with StSKP1, retained the capacity to enable AGO1 decay. Thus, unlike other P0 proteins of previously characterized poleroviruses, P0PL‐Ar seems to have a dual activity, according to the findings of this study. This protein would act at both an upstream and a downstream step of the RNA silencing pathway: upstream of Dicer‐like enzyme (DCL)‐mediated primary siRNA production and downstream at the RNA‐induced silencing complex (RISC) complex level. Our results contribute to the understanding of the different ways PLRV P0 proteins function as silencing suppressors.

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“…Several viral proteins interacting with SKP1 have been identified, including Clinkprotein, which is encoded by the single-stranded DNA nanovirus faba bean necrotic yellows virus (FBNYV), P0 protein encoded by the poleroviruses beet western yellows virus (BWYV), cucurbit aphid-borne yellows virus (CABYV), brassica yellows virus (BrYV), P7-2 encoded by rice black-streaked dwarf virus (RBSDV), and βC1 encoded by cotton leaf curl Multan virus (CLCuMuV) [16,17,18,19,20]. Among these, the silencing suppressor protein P0 of BWYV and CABYV functions as an F-box protein that targets AGO1 for degradation via the autophagy pathway [21,22,23,24,25]. Although several proteins have been reported to interact with SKP1, only the Polerovirus silencing suppressor P0 has the properties of an F-box protein.…”

Section: Introductionmentioning

confidence: 99%

Cucurbit Chlorotic Yellows Virus p22 Protein Interacts with Cucumber SKP1LB1 and Its F-Box-Like Motif Is Crucial for Silencing Suppressor Activity

Chen

Xin-yan

Shi

et al. 2019

Viruses

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Plants use RNA silencing as a defense against viruses. In response, viruses encode various RNA silencing suppressors to counteract the antiviral silencing. Here, we identified p22 as a silencing suppressor of cucurbit chlorotic yellows crinivirus and showed that p22 interacts with CsSKP1LB1, a Cucumis sativus ortholog of S-phase kinase-associated protein 1 (SKP1). The F-box-like motif of p22 was identified through sequence analysis and found to be necessary for the interaction using a yeast two-hybrid assay. The involvement of the F-box-like motif in p22 silencing suppressor activity was determined. Proteomics analysis of Nicotiana benthamiana leaves expressing p22, and its F-box-like motif deletion mutant showed 228 differentially expressed proteins and five enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways: ABC transporters, sesquiterpenoid and triterpenoid biosynthesis, ubiquitin-mediated proteolysis, riboflavin metabolism, and cysteine and methionine metabolism. Collectively, our results demonstrate the interaction between p22 and CsSKP1LB1 and show that the deletion of F-box-like motif inhibits p22 silencing suppressor activity. The possible pathways regulated by the p22 through the F-box-like motif were identified using proteomics analysis.

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The Three Essential Motifs in P0 for Suppression of RNA Silencing Activity of Potato leafroll virus Are Required for Virus Systemic Infection

Cited by 12 publications

References 44 publications

Functional Characterization of RNA Silencing Suppressor P0 from Pea Mild Chlorosis Virus

Functional Characterization of RNA Silencing Suppressor P0 from Pea Mild Chlorosis Virus

Argentinian potato leafroll virus P0 protein: Novel activities for a previously known suppressor

Cucurbit Chlorotic Yellows Virus p22 Protein Interacts with Cucumber SKP1LB1 and Its F-Box-Like Motif Is Crucial for Silencing Suppressor Activity

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