Plant Defense and Viral Counter-Defense during Plant–Geminivirus Interactions

Zhang, Jianhang; Ma, Mengyuan; Liu, Yule; Ismayil, Asigul

doi:10.3390/v15020510

Cited by 10 publications

(7 citation statements)

References 160 publications

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“…Begomovirus proteins have been shown to target enzymes in the host methyl cycle or in DNA methylation pathways directly to repress methylation ( Wang et al., 2020 ; Gui et al., 2022 ). Suppression of TGS alters the methylation status of the host genome as well as viral DNA ( Gui et al., 2022 ; Zhang et al., 2023 ). Begomovirus infection has been associated with demethylation and activation of transposable elements in the host genome ( Gui et al., 2022 ; Guo et al., 2022 ) and similarly might activate the genomic copy of SEGS-1 in cassava.…”

Section: Discussionmentioning

confidence: 99%

SEGS-1 a cassava genomic sequence increases the severity of African cassava mosaic virus infection in Arabidopsis thaliana

Rajabu,

Dallas,

Chiunga

et al. 2023

Front. Plant Sci.

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Cassava is a major crop in Sub-Saharan Africa, where it is grown primarily by smallholder farmers. Cassava production is constrained by Cassava mosaic disease (CMD), which is caused by a complex of cassava mosaic begomoviruses (CMBs). A previous study showed that SEGS-1 (sequences enhancing geminivirus symptoms), which occurs in the cassava genome and as episomes during viral infection, enhances CMD symptoms and breaks resistance in cassava. We report here that SEGS-1 also increases viral disease severity in Arabidopsis thaliana plants that are co-inoculated with African cassava mosaic virus (ACMV) and SEGS-1 sequences. Viral disease was also enhanced in Arabidopsis plants carrying a SEGS-1 transgene when inoculated with ACMV alone. Unlike cassava, no SEGS-1 episomal DNA was detected in the transgenic Arabidopsis plants during ACMV infection. Studies using Nicotiana tabacum suspension cells showed that co-transfection of SEGS-1 sequences with an ACMV replicon increases viral DNA accumulation in the absence of viral movement. Together, these results demonstrated that SEGS-1 can function in a heterologous host to increase disease severity. Moreover, SEGS-1 is active in a host genomic context, indicating that SEGS-1 episomes are not required for disease enhancement.

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Section: Discussionmentioning

confidence: 99%

SEGS-1 a cassava genomic sequence increases the severity of African cassava mosaic virus infection in Arabidopsis thaliana

Rajabu,

Dallas,

Chiunga

et al. 2023

Front. Plant Sci.

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“…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%

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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“…To counteract this defense, the begomovirus genome encodes viral suppressors of RNA silencing (VSRs) [ 86 , 87 ]. Regarding begomoviral proteins associated with virus movement, V2 and C4 inhibit both transcriptional gene silencing (TGS) and posttranscriptional gene silencing (PTGS) [ 86 , 87 , 88 ]. V2 from cotton leaf curl Multan virus (CLCuMuV) effectively counteracts TGS by directly interacting with Argonaute 4 (AGO4) and suppressing RNA-dependent DNA Methylation (RdDM)-mediated TGS [ 89 ].…”

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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Plant Defense and Viral Counter-Defense during Plant–Geminivirus Interactions

Cited by 10 publications

References 160 publications

SEGS-1 a cassava genomic sequence increases the severity of African cassava mosaic virus infection in Arabidopsis thaliana

SEGS-1 a cassava genomic sequence increases the severity of African cassava mosaic virus infection in Arabidopsis thaliana

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

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

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