Publications by authors named "Merike Somera"

ATP-BINDING CASSETTE SUBFAMILY E MEMBER (ABCE) proteins are one of the most conserved proteins across eukaryotes and archaea. Yeast and most animals possess a single gene encoding the critical translational factor ABCE1. In several plant species, including and , two or more gene copies have been identified, however information related to plant gene family is still missing.

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The discrepancy between short- and long-term rate estimates, known as the time-dependent rate phenomenon (TDRP), poses a challenge to extrapolating evolutionary rates over time and reconstructing evolutionary history of viruses. The TDRP reveals a decline in evolutionary rate estimates with the measurement timescale, explained empirically by a power-law rate decay, notably observed in animal and human viruses. A mechanistic evolutionary model, the Prisoner of War (PoW) model, has been proposed to address TDRP in viruses.

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We report sequencing of four historical cynosurus mottle virus (CnMoV) isolates, originating from different hosts and locations. The CnMoV genome, ranging from 4417 to 4419 nt, encodes five ORFs. It shares 48.

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Oat sterile dwarf virus (OSDV) is a fijivirus whose genome segments 7 to 10 were sequenced earlier. In the current study, the complete genome was sequenced. To confirm the genome ends, rapid amplification and sequencing of cDNA ends were performed.

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Recent developments in high-throughput sequencing (HTS) technologies and bioinformatics have drastically changed research in virology, especially for virus discovery. Indeed, proper monitoring of the viral population requires information on the different isolates circulating in the studied area. For this purpose, HTS has greatly facilitated the sequencing of new genomes of detected viruses and their comparison.

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Due to an increase in the consumption of food, feed, and fuel and to meet global food security needs for the rapidly growing human population, there is a necessity to obtain high-yielding crops that can adapt to future climate changes. Currently, the main feed source used for ruminant livestock production is forage grasses. In temperate climate zones, perennial grasses grown for feed are widely distributed and tend to suffer under unfavorable environmental conditions.

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Crop adaptation to climate change is in a part attributed to epigenetic mechanisms which are related to response to abiotic and biotic stresses. Although recent studies increased our knowledge on the nature of these mechanisms, epigenetics remains under-investigated and still poorly understood in many, especially non-model, plants, Epigenetic modifications are traditionally divided into two main groups, DNA methylation and histone modifications that lead to chromatin remodeling and the regulation of genome functioning. In this review, we outline the most recent and interesting findings on crop epigenetic responses to the environmental cues that are most relevant to climate change.

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The family includes viruses with icosahedral particles (26-34 nm in diameter) assembled on =3 symmetry with a 4-6 kb positive-sense, monopartite, polycistronic RNA genome. Transmission of members of the genera and occurs via mechanical wounding, vegetative propagation, insect vectors or abiotically through soil; members of the genera and are transmitted by specific aphids. Most solemoviruses have a narrow host range.

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Worldwide, barley/cereal yellow dwarf viruses (YDVs) are the most widespread and damaging group of cereal viruses. In this study, we applied high-throughput sequencing technologies (HTS) to perform a virus survey on symptomatic plants from 47 cereal fields in Estonia. HTS allowed the assembly of complete genome sequences for 22 isolates of cereal yellow dwarf virus RPS, barley yellow dwarf virus GAV, barley yellow dwarf virus PAS (BYDV-PAS), barley yellow dwarf virus PAV (BYDV-PAV), and barley yellow dwarf virus OYV (BYDV-OYV).

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High-throughput sequencing technologies were used to identify plant viruses in cereal samples surveyed from 2012 to 2017. Fifteen genome sequences of a tenuivirus infecting wheat, oats, and spelt in Estonia, Norway, and Sweden were identified and characterized by their distances to other tenuivirus sequences. Like most tenuiviruses, the genome of this tenuivirus contains four genomic segments.

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Solanum nodiflorum mottle virus (SNMoV) was isolated from a small-flowered nightshade (Solanum nodiflorum) in Queensland, Australia. It has been included in the genus Sobemovirus based on virion morphology and serological relationships. Here, we report the sequence of the complete genome of SNMoV.

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Sobemovirus P1 protein, characterized previously as a suppressor of posttranscriptional gene silencing, is required for systemic virus spread and infection in plants. Mutations in the ORF1 initiation codon do not affect viral replication indicating P1 is not necessary for this process. Wild type, recombinant and P1 deletion mutants of Cocksfoot mottle virus and Rice yellow mottle virus were used to infect oat, rice, wheat, barley, Arabidopsis thaliana and Nicotiana benthamiana plants.

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The genus Sobemovirus, unassigned to any family, consists of viruses with single-stranded plus-oriented single-component RNA genomes and small icosahedral particles. Currently, 14 species within the genus have been recognized by the International Committee on Taxonomy of Viruses (ICTV) but several new species are to be recognized in the near future. Sobemovirus genomes are compact with a conserved structure of open reading frames and with short untranslated regions.

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Once considered a tentative member of the genus Sobemovirus, rottboellia yellow mottle virus (RoMoV) was excluded from the latest species list of the ICTV after the discovery of imperata yellow mottle virus (IYMV), which resembles RoMoV in host range and geographic origin. Here, sequence analysis of the complete genome of RoMoV suggested that it should be considered a distinct species within the genus Sobemovirus. It has the highest sequence identity (55 %) to ryegrass mottle virus (RGMoV), whereas its sequence identity to IYMV is lower (44 %).

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Unlike other sobemoviruses, lucerne transient streak virus (LTSV) and turnip rosette virus (TRoV) have been reported to contain two successive ORF1s (denoted as ORF1a and ORF1b) instead of a single ORF1. Also, their next ORF (ORF2a/2a2b) has been mapped to a region ca. 200 nucleotides downstream from that of other sobemoviruses, leading to the lack of transmembrane segments at the N-termini of P2a/2a2b.

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Cocksfoot mottle virus (CfMV) localization in oat plants was analyzed during three weeks post infection by immunohistochemical staining to follow its spread through different tissues. In early stages of infection, the virus was first detectable in phloem parenchyma and bundle sheath cells of inoculated leaves. Bundle sheath and phloem parenchyma were also the cell types where the virus was first detected in stems and systemic leaves of infected plants.

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