Geminiviral C4/AC4 proteins: An emerging component of the viral arsenal against plant defence

Kumar, Rohit; Dasgupta, Indranil

doi:10.1016/j.virol.2023.01.005

Cited by 7 publications

(5 citation statements)

References 206 publications

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“…Evidence for V2 MP activity of is currently emerging for a number of other monopartite geminiviruses [206][207][208][209][210]. Interestingly, the V2 protein has been shown to interact directly with the C4 protein, dramatically enhancing the accumulation of this viral protein [211,212], which, in turn, is capable of participating in virus cell-to-cell movement [213][214][215]. Consistent with this, at least a fraction of C4 molecules may be concentrated in PD [216,217].…”

Section: Order Geplafuvirales Family Geminiviridaementioning

confidence: 89%

“…In general, many studies have shown that C1 and C2 proteins encoded by different geminiviruses can suppress silencing (Table 1 and Figure 1). Being pathogenicity determinants of geminiviruses, both V2 and C4 proteins also exhibit VSR activity [215,[218][219][220][221][222][223][224][225][226][227][228].…”

Section: Order Geplafuvirales Family Geminiviridaementioning

confidence: 99%

“…The C4 protein is known to suppress both PTGS and TGS. To counteract TGS, C4 suppresses SAM synthetase enzyme activity and interacts with AGO4 to eliminate viral genome methylation [210,214,215]. In addition, some C4 proteins specifically interfere with the cell-to-cell and/or systemic spread of silencing [217,223,227,229].…”

Section: Order Geplafuvirales Family Geminiviridaementioning

confidence: 99%

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Role of Plant Virus Movement Proteins in Suppression of Host RNAi Defense

Atabekova

Solovieva

Chergintsev

et al. 2023

IJMS

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One of the systems of plant defense against viral infection is RNA silencing, or RNA interference (RNAi), in which small RNAs derived from viral genomic RNAs and/or mRNAs serve as guides to target an Argonaute nuclease (AGO) to virus-specific RNAs. Complementary base pairing between the small interfering RNA incorporated into the AGO-based protein complex and viral RNA results in the target cleavage or translational repression. As a counter-defensive strategy, viruses have evolved to acquire viral silencing suppressors (VSRs) to inhibit the host plant RNAi pathway. Plant virus VSR proteins use multiple mechanisms to inhibit silencing. VSRs are often multifunctional proteins that perform additional functions in the virus infection cycle, particularly, cell-to-cell movement, genome encapsidation, or replication. This paper summarizes the available data on the proteins with dual VSR/movement protein activity used by plant viruses of nine orders to override the protective silencing response and reviews the different molecular mechanisms employed by these proteins to suppress RNAi.

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Section: Order Geplafuvirales Family Geminiviridaementioning

confidence: 89%

Section: Order Geplafuvirales Family Geminiviridaementioning

confidence: 99%

Section: Order Geplafuvirales Family Geminiviridaementioning

confidence: 99%

See 1 more Smart Citation

Role of Plant Virus Movement Proteins in Suppression of Host RNAi Defense

Atabekova

Solovieva

Chergintsev

et al. 2023

IJMS

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“…Geminiviruses are a group of plant viruses that cause severe agricultural losses worldwide [ 28 ]. In geminivirus–plant arms races, plants have developed effective strategies targeting viral infection steps.…”

Section: Discussionmentioning

confidence: 99%

The C4 Protein of TbLCYnV Promotes SnRK1 β2 Degradation Via the Autophagy Pathway to Enhance Viral Infection in N. benthamiana

Li,

Zhao,

Yang

et al. 2024

Viruses

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Geminiviruses are a group of single-stranded DNA viruses that have developed multiple strategies to overcome host defenses and establish viral infections. Sucrose nonfermenting-1-related kinase 1 (SnRK1) is a key regulator of energy balance in plants and plays an important role in plant development and immune defenses. As a heterotrimeric complex, SnRK1 is composed of a catalytic subunit α (SnRK1 α) and two regulatory subunits, β and γ. Previous studies on SnRK1 in plant defenses against microbial pathogens have mainly focused on SnRK1 α. In this study, we validated the interaction between the C4 protein encoded by tobacco leaf curl Yunnan virus (TbLCYnV) and the regulatory subunit β of Nicotiana benthamiana SnRK1, i.e., NbSnRK1 β2, and identified that the Asp22 of C4 is critical for TbLCYnV C4–NbSnRK1 β2 interactions. NbSnRK1 β2 silencing in N. benthamiana enhances susceptibility to TbLCYnV infection. Plants infected with viral mutant TbLCYnV (C4D22A), which contains the mutant version C4 (D22A) that is incapable of interacting with NbSnRK1 β2, display milder symptoms and lower viral accumulation. Furthermore, we discovered that C4 promotes NbSnRK1 β2 degradation via the autophagy pathway. We herein propose a model by which the geminivirus C4 protein causes NbSnRK1 β2 degradation via the TbLCYnV C4–NbSnRK1 β2 interaction to antagonize host antiviral defenses and facilitates viral infection and symptom development in N. benthamiana.

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“…The C4 protein inhibits SAM synthetase enzyme activity and interacts with AGO4 to reduce viral genome methylation [ 92 , 93 , 94 ]. Additionally, specific C4 proteins interfere with the spread of the RNA silencing signal between cells and/or systemically [ 95 , 96 ].…”

Section: Functions Of Movement Proteins In Suppression Of Host Defensesmentioning

confidence: 99%

Begomovirus–Host Interactions: Viral Proteins Orchestrating Intra and Intercellular Transport of Viral DNA While Suppressing Host Defense Mechanisms

Breves,

Silva,

Euclydes

et al. 2023

Viruses

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Begomoviruses, which belong to the Geminiviridae family, are intracellular parasites transmitted by whiteflies to dicotyledonous plants thatsignificantly damage agronomically relevant crops. These nucleus-replicating DNA viruses move intracellularly from the nucleus to the cytoplasm and then, like other plant viruses, cause disease by spreading systemically throughout the plant. The transport proteins of begomoviruses play a crucial role in recruiting host components for the movement of viral DNA within and between cells, while exhibiting functions that suppress the host’s immune defense. Pioneering studies on species of the Begomovirus genus have identified specific viral transport proteins involved in intracellular transport, cell-to-cell movement, and systemic spread. Recent research has primarily focused on viral movement proteins and their interactions with the cellular host transport machinery, which has significantly expanded understanding on viral infection pathways. This review focuses on three components within this context: (i) the role of viral transport proteins, specifically movement proteins (MPs) and nuclear shuttle proteins (NSPs), (ii) their ability to recruit host factors for intra- and intercellular viral movement, and (iii) the suppression of antiviral immunity, with a particular emphasis on bipartite begomoviral movement proteins.

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Geminiviral C4/AC4 proteins: An emerging component of the viral arsenal against plant defence

Cited by 7 publications

References 206 publications

Role of Plant Virus Movement Proteins in Suppression of Host RNAi Defense

Role of Plant Virus Movement Proteins in Suppression of Host RNAi Defense

The C4 Protein of TbLCYnV Promotes SnRK1 β2 Degradation Via the Autophagy Pathway to Enhance Viral Infection in N. benthamiana

Begomovirus–Host Interactions: Viral Proteins Orchestrating Intra and Intercellular Transport of Viral DNA While Suppressing Host Defense Mechanisms

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