Search results for "Virus"
showing 10 items of 5024 documents
The effect of RNA substitution models on viroid and RNA virus phylogenies.
2018
Abstract Many viroids and RNA viruses have genomes that exhibit secondary structure, with paired nucleotides forming stems and loops. Such structures violate a key assumption of most methods of phylogenetic reconstruction, that sequence change is independent among sites. However, phylogenetic analyses of these transmissible agents rarely use evolutionary models that account for RNA secondary structure. Here, we assess the effect of using RNA-specific nucleotide substitution models on the phylogenetic inference of viroids and RNA viruses. We obtained data sets comprising full-genome nucleotide sequences from six viroid and ten single-stranded RNA virus species. For each alignment, we inferre…
Citrus rootstock breeding: response of four allotetraploid somatic hybrids to Citrus tristeza virus induced infections
2018
Four allotetraploid somatic hybrids of citrus, with potential for rootstock improvement, have been evaluated for their response to Citrus tristeza virus (CTV) infection. CTV is the most important viral pathogen affecting citrus production worldwide. Somatic combinations of ‘Milam’ lemon (Citrus jambhiri Lush.) + Sour orange (C. aurantium L Osb.), Calamondin (C. madurensis Lour.) + ‘Keen’ sour orange (C. aurantium L.), Calamondin + ‘Femminello‘ lemon (C. limon L. Burm. F.) and Cleopatra mandarin (C. reshni Hort. ex Tan.) + ‘Femminello’ lemon, were studied. Plants were grafted with CTV-infected “Valencia” sweet orange budwood. Two different CTV strains collected in Sicily, considered as “mild…
Genetic variation and evolutionary analysis ofPepino mosaic virusin Sicily: insights into the dispersion and epidemiology
2017
Pepino mosaic virus (PepMV) is a highly infectious potexvirus that causes a severe disease in tomato (Solanum lycopersicum) crops worldwide. In Sicily, the first outbreak was detected in a single greenhouse in 2005 and it was promptly eradicated. However, in 2008, a large number of greenhouses were simultaneously affected, and it was impossible to eradicate or control the virus. This study addressed the dispersion and the genetic diversity of PepMV isolates obtained from the outbreak in Sicily, in comparison with worldwide PepMV isolates, to gain insight into the factors determining the evolution and epidemiology of the virus. A total of 1800 samples from plants with and without symptoms we…
Enhancing heterologous protein expression and secretion in HEK293 cells by means of combination of CMV promoter and IFNα2 signal peptide
2016
Efficient production and secretion of recombinant proteins in mammalian cell lines relies in a combination of genetic, metabolic and culture strategy factors. The present work assesses the influence of two key genetic components of expression vectors (promoter and signal peptide) on protein production and secretion effciency in HEK293 cells expressing eGFP as a reporter protein. Firstly, the strength of 3 different promoters was evaluated using transient expression methods. Flow cytometry analysis revealed that the highest level of intracellular protein expression was found when eGFP was under the control of CMV promoter, being 3-times higher in comparison to the rest of the promoters teste…
First outbreak of Pepper vein yellows virus infecting sweet pepper in Italy
2016
Sweet pepper (Capsicum annum) is an economically important crop worldwide, including Sicily where about 4,000 hectares are grown each year. In October 2015, severe symptoms not previously reported by growers in the horticultural area of the province of Trapani (Sicily, Italy) were observed on sweet pepper plants in eight different greenhouses. Symptoms included upward leaf curling, internodal shortening and interveinal yellowing. Symptoms were more evident in the upper part of the plants. These symptoms were reminiscent of those caused by poleroviruses. In the greenhouse, symptoms were evident in about 35% of the plants. Three samples per greenhouse (24 in total) were collected for analysis.
Survey of five major grapevine viruses infecting Blatina and Žilavka cultivars in Bosnia and Herzegovina
2021
The sanitary status of grapevines has not yet been considered sufficiently in vineyards throughout Bosnia and Herzegovina (BiH). An extensive survey of five major grapevine viruses in the country was carried out in 2019. A total of 630 samples from the two dominant autochthonous cultivars, named Žilavka and Blatina, were tested by DAS-ELISA for the presence of grapevine leafroll-associated viruses (GLRaV-1 and 3), grapevine fleck virus (GFkV), grapevine fanleaf virus (GFLV) and Arabis mosaic virus (ArMV). Eighty-eight % of the samples were positive for at least one virus, and all five viruses were detected, thought with different incidence, i.e. GLRaV-3 (84%), GFLV (43%), GLRaV-1 (14%), GFk…
Begomoviruses Infecting Tomato Crops in Panama
2015
The key regions in Panama involved in open field- and greenhouse-grown commercial tomato production, including the Chiriquí, Veraguas, Herrera, Los Santos, Coclé and Panama Oeste provinces, were surveyed for the incidence and distribution of begomoviruses in the growing seasons of 2011 and 2012. The surveys took place in 14 of the 51 districts of the above-mentioned provinces and comprised all relevant tomato production areas of the provinces. A total of 28 tomato plots were surveyed. The exact location of each plot was geo-referenced using a hand-held Global Positioning System unit. In total, 319 individual tomato plants (181 in 2011 and 138 in 2012) were sampled. Plants displayed diverse …
Symptom severity, infection progression and plant responses in solanum plants caused by three pospiviroids vary with the inoculation procedure
2021
This article belongs to the Section Molecular Plant Sciences.
Symbiotic polydnavirus and venom reveal parasitoid to its hyperparasitoids
2018
Symbiotic relationships benefit organisms in utilization of new niches. In parasitoid wasps, symbiotic viruses and venom that are injected together with wasp eggs into the host caterpillar suppress immune responses of the host and enhance parasitoid survival. We found that the virus also has negative effects on offspring survival when placing these interactions in a community context. The virus and venom drive a chain of interactions that includes the herbivore and its food plant and attracts the hyperparasitoid enemies of the parasitoid. Our results shed new light on the importance of symbionts associated with their host in driving ecological interactions and highlight the intricacy of how…
Occurrence of the T36 Genotype of Citrus tristeza virus in Citrus Orchards in Sicily, Italy
2016
Recent phylogenetic studies have shown that different lineages representing mild and virulent Citrus tristeza virus (CTV) isolates have been present in Italy for a long time. The genetic structure of CTV population, based on p23 and p27 genes sequences, highlighted two main clusters referred to as T30 and VT-like, as confirmed by the full genomes sequences of two representative isolates SG29 (KC748392) and Bau282 (KC748391) (Licciardello et al. 2015). On the basis of risk analyses, regulatory measures have been outlined, including the recommendation to replace sour orange (C. aurantium) with tolerant rootstocks and to monitor the spread and the presence (if any) of different isolates not co…