1,721,003 research outputs found

    Simultaneous detection of 10 viruses in globe artichoke by a synthetic oligonucleotide-based DNA polyprobe

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    Most of the 26 viruses that infect globe artichoke are detrimental to the crop’s production, quality, and nutritional value, hamper the development of a nursery activity in the respect of current EU legislation and pose risks for the new plantings. Worldwide movement of virus-controlled plant propagative material require fast, accurate and feasible methods to guarantee reliable results and detection of multiple viruses in a single assay to reduce time and costs in routine tests. Here we describe the use of a digoxigenin-labelled polyprobe assembled from synthetic 50 nt single-stranded DNA sequences derived from genomes of the most commonly occurring viruses in globe artichoke. These included artichoke Italian latent virus (AILV), artichoke latent virus (ArLV), artichoke mottled crinkle virus (AMCV), turnip mosaic virus (TuMV), tomato infectious chlorosis virus (TICV), bean yellow mosaic virus (BYMV), cucumber mosaic virus (CMV), pelargonium zonate spot virus (PZSV), tomato spotted wilt virus (TSWV) and tobacco mosaic virus (TMV). The polyprobe described herein represent the first cheap and reliable example of a technology for broad-spectrum surveys in globe artichoke. © 2021, Koninklijke Nederlandse Planteziektenkundige Vereniging

    The role of grafting in the resistance of tomato to viruses

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    Grafting is routinely implemented in modern agriculture to manage soilborne pathogens such as fungi, oomycetes, bacteria, and viruses of solanaceous crops in a sustainable and environmentally friendly approach. Some rootstock/scion combinations use specific genetic resistance mechanisms to impact also some foliar and airborne pathogens, including arthropod or contact-transmitted viruses. These approaches resulted in poor efficiency in the management of plant viruses with superior virulence such as the strains of tomato spotted wilt virus breaking the Sw5 resistance, strains of cucumber mosaic virus carrying necrogenic satellite RNAs, and necrogenic strains of potato virus Y. Three different studies from our lab documented that suitable levels of resistance/tolerance can be obtained by grafting commercial tomato varieties onto the tomato ecotype Manduria (Ma) rescued in the framework of an Apulian (southern Italy) regional program on biodiversity. Here we review the main approaches, methods, and results of the three case studies and propose some mechanisms leading to the tolerance/resistance observed in susceptible tomato varieties grafted onto Ma as well as in self-grafted plants. The proposed mechanisms include virus movement in plants, RNA interference, genes involved in graft wound response, resilience, and tolerance to virus infection

    Grafting to manage infections of top stunting and necrogenic strains of cucumber mosaic virus in tomato

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    Cucumber mosaic virus (CMV) lists among the most important etiological agents of tomato diseases. Some isolates of CMV function as helper virus for replication, encapsidation and transmission of satellite RNAs (satRNA), which may exacerbate symptoms induced by CMV in certain hosts. Outbreaks of CMV strains supporting hypervirulent variants of satRNAs are recurrent in tomato with devastating effects on crop production and efficient control measures are still unavailable. In this study, we examined the dynamics of infection of the CMV strains tomato top stunting (TTS) and 77 supporting replication of satRNA variants that codetermine top stunting (TTS-satRNA) and necrotic (77-satRNA) phenotypes in two tomato cultivars denoted Solanum lycopersicum Manduria (Sl-Ma) and S. lycopersicum UC82 (Sl-UC). Sl-Ma but not Sl-UC recovered from disease symptoms induced by CMV-TTS while both the cultivars succumbed to the infection of CMV-77 and its necrogenic satRNA. Ability to recover of the Sl-Ma plants was transmitted by grafting to the susceptible genotype Sl-UC. More interestingly, recovery was observed also against the challenge inoculation of CMV plus 77-satRNA in plants grafted on Sl-Ma and in self-grafted plants of both the Sl-Ma and Sl-UC cultivars. Analysis of small RNAs and genes of the defence plant response based on RNA interference (RNAi) suggested that RNAi is involved in the recovery of Sl-Ma against CMV with hypervirulent satRNAs and in scions grafted on this rootstock. The response of Sl-Ma to the inoculation of CMV-77 plus 77-satRNA was compared with that of the transgenic tomato line S. lycopersicum transgenic line UCTC5.9.2 that expresses constitutively the benign variant of the satRNA denoted Tfn-satRNA. Comparative analysis suggested that the response may operate via similar mechanisms, which involve RNAi, the graft and the presence of the satRNA

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed

    Variations on the Author

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    “Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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