Molecular interactions of plant viral satellites

Badar, Uzma; Venkataraman, Srividhya; AbouHaidar, Mounir G.; Hefferon, Kathleen

doi:10.1007/s11262-020-01806-9

Cited by 18 publications

(31 citation statements)

References 219 publications

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“…This resistance is based on several biological principles (Galvez et al, 2014). The first generation of transgenic virus-resistant plants was prepared using so-called satellite RNA sequences: these are, in essence, molecular parasites of viruses that use the gene products of their helper virus for replication (Badar et al, 2021). They were discovered because their presence can decrease the virulence of the associated virus.…”

Section: Virus Resistancementioning

confidence: 99%

Transgenic approaches for plant disease control: Status and prospects 2021

Collinge

Sarrocco

2021

Plant Pathology

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Plant diseases are responsible for major crop losses and postharvest spoilage; though losses are difficult to calculate, educated estimates suggest they are responsible for 20% to 40% of losses from plough to plate for major crops (Oerke, 2006;Savary et al., 2019). Hypothetically, with current estimated population growth, we could solve the challenge of feeding the world by 2050 were we able to control all disease (Collinge et al., 2010). Plant disease can be managed primarily by farmer skill, pesticides, disease resistance, and biological control, in roughly that order of importance. Disease resistance is effective when it works because no specific input is required by the grower after sowing or planting. However, despite major effort by plant pathologists and breeders over a century, no effective disease-resistant cultivars are available for many diseases, and, for many important diseases, the pathogen overcomes natural

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Section: Virus Resistancementioning

confidence: 99%

Transgenic approaches for plant disease control: Status and prospects 2021

Collinge

Sarrocco

2021

Plant Pathology

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“…Can such a gene-free genome exist? Viroids, small circular satellite RNAs (satRNAs) and several other groups of similar RNA elements prove that such genomes can and do exist (Figure 1) [6][7][8][9][10]. However, there are no known ribozyme RdRPs.…”

Section: Introductionmentioning

confidence: 99%

“…The two families of viroids also vary in their choice of the ligase: members of Pospiviroidae use host DNA ligase 1 that they repurpose as RNA ligase [33], whereas members of Avsunviroidae, which replicate within plastids, use chloroplast tRNA ligase [34]. Broadly similar to viroids in terms of structure, replication, and range, satRNAs differ in that they are encapsidated, albeit by a helper virus rather than by proteins they encode themselves [10,35]. Furthermore, satRNAs do not rely on host DdRP for replication, but instead employ the RNA-dependent RNA polymerase (RdRP) of the helper virus [12,36].…”

Section: Introductionmentioning

confidence: 99%

Viroids and Viroid-like Circular RNAs: Do They Descend from Primordial Replicators?

Lee

Koonin

2022

Life

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Viroids are a unique class of plant pathogens that consist of small circular RNA molecules, between 220 and 450 nucleotides in size. Viroids encode no proteins and are the smallest known infectious agents. Viroids replicate via the rolling circle mechanism, producing multimeric intermediates which are cleaved to unit length either by ribozymes formed from both polarities of the viroid genomic RNA or by coopted host RNAses. Many viroid-like small circular RNAs are satellites of plant RNA viruses. Ribozyviruses, represented by human hepatitis delta virus, are larger viroid-like circular RNAs that additionally encode the viral nucleocapsid protein. It has been proposed that viroids are direct descendants of primordial RNA replicons that were present in the hypothetical RNA world. We argue, however, that much later origin of viroids, possibly, from recently discovered mobile genetic elements known as retrozymes, is a far more parsimonious evolutionary scenario. Nevertheless, viroids and viroid-like circular RNAs are minimal replicators that are likely to be close to the theoretical lower limit of replicator size and arguably comprise the paradigm for replicator emergence. Thus, although viroid-like replicators are unlikely to be direct descendants of primordial RNA replicators, the study of the diversity and evolution of these ultimate genetic parasites can yield insights into the earliest stages of the evolution of life.

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“…All subviral RNAs are characterized by their inability to independently complete an infection cycle, which includes transmission to the next host plant. Subviral RNAs range substantially in size and complexity, from non-coding satellite RNAs (194 nt to about 500 nt) that depend on their helper virus for replication, movement and encapsidation [1] to a variety of translated RNAs such as satellite viruses that encode their own capsid protein but depend on the helper virus for replication and movement [2]. Subviral RNAs can markedly affect disease symptoms associated with their helper virus, either attenuating or exacerbating symptoms, which can vary depending on the host.…”

Section: Introductionmentioning

confidence: 99%

Structural Analysis and Whole Genome Mapping of a New Type of Plant Virus Subviral RNA: Umbravirus-Like Associated RNAs

Liu

Carino

Bera

et al. 2021

Viruses

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We report the biological and structural characterization of umbravirus-like associated RNAs (ulaRNAs), a new category of coat-protein dependent subviral RNA replicons that infect plants. These RNAs encode an RNA-dependent RNA polymerase (RdRp) following a −1 ribosomal frameshift event, are 2.7–4.6 kb in length, and are related to umbraviruses, unlike similar RNA replicons that are related to tombusviruses. Three classes of ulaRNAs are proposed, with citrus yellow vein associated virus (CYVaV) placed in Class 2. With the exception of CYVaV, Class 2 and Class 3 ulaRNAs encode an additional open reading frame (ORF) with movement protein-like motifs made possible by additional sequences just past the RdRp termination codon. The full-length secondary structure of CYVaV was determined using Selective 2’ Hydroxyl Acylation analyzed by Primer Extension (SHAPE) structure probing and phylogenic comparisons, which was used as a template for determining the putative structures of the other Class 2 ulaRNAs, revealing a number of distinctive structural features. The ribosome recoding sites of nearly all ulaRNAs, which differ significantly from those of umbraviruses, may exist in two conformations and are highly efficient. The 3′ regions of Class 2 and Class 3 ulaRNAs have structural elements similar to those of nearly all umbraviruses, and all Class 2 ulaRNAs have a unique, conserved 3′ cap-independent translation enhancer. CYVaV replicates independently in protoplasts, demonstrating that the reported sequence is full-length. Additionally, CYVaV contains a sequence in its 3′ UTR that confers protection to nonsense mediated decay (NMD), thus likely obviating the need for umbravirus ORF3, a known suppressor of NMD. This initial characterization lays down a road map for future investigations into these novel virus-like RNAs.

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Molecular interactions of plant viral satellites

Cited by 18 publications

References 219 publications

Transgenic approaches for plant disease control: Status and prospects 2021

Transgenic approaches for plant disease control: Status and prospects 2021

Viroids and Viroid-like Circular RNAs: Do They Descend from Primordial Replicators?

Structural Analysis and Whole Genome Mapping of a New Type of Plant Virus Subviral RNA: Umbravirus-Like Associated RNAs

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