de Oliveira A.S.,University of Brasilia |
Melo F.L.,University of Brasilia |
Inoue-Nagata A.K.,Embrapa Vegetables |
Nagata T.,University of Brasilia |
And 2 more authors.
PLoS ONE | Year: 2012
Background: Tospoviruses (Genus Tospovirus, Family Bunyaviridae) are phytopathogens responsible for significant worldwide crop losses. They have a tripartite negative and ambisense RNA genome segments, termed S (Small), M (Medium) and L (Large) RNA. The vector-transmission is mediated by thrips in a circulative-propagative manner. For new tospovirus species acceptance, several analyses are needed, e.g., the determination of the viral protein sequences for enlightenment of their evolutionary history. Methodology/Principal Findings: Biological (host range and symptomatology), serological, and molecular (S and M RNA sequencing and evolutionary studies) experiments were performed to characterize and differentiate a new tospovirus species, Bean necrotic mosaic virus (BeNMV), which naturally infects common beans in Brazil. Based upon the results, BeNMV can be classified as a novel species and, together with Soybean vein necrosis-associated virus (SVNaV), they represent members of a new evolutionary lineage within the genus Tospovirus. Conclusion/Significances: Taken together, these evidences suggest that two divergent lineages of tospoviruses are circulating in the American continent and, based on the main clades diversity (American and Eurasian lineages), new tospovirus species related to the BeNMV-SVNaV clade remain to be discovered. This possible greater diversity of tospoviruses may be reflected in a higher number of crops as natural hosts, increasing the economic impact on agriculture. This idea also is supported since BeNMV and SVNaV were discovered naturally infecting atypical hosts (common bean and soybean, respectively), indicating, in this case, a preference for leguminous species. Further studies, for instance a survey focusing on crops, specifically of leguminous plants, may reveal a greater tospovirus diversity not only in the Americas (where both viruses were reported), but throughout the world. © 2012 de Oliveira et al.
Albuquerque L.C.,University of Brasilia |
Martin D.P.,University of Cape Town |
Avila A.C.,Embrapa Vegetables |
Inoue-Nagata A.K.,University of Brasilia
Virus Genes | Year: 2010
Tomato yellow vein streak virus (ToYVSV) is a tentative begomovirus (Family Geminiviridae) species that seriously affects tomato and potato production in Brazil. Here, we have determined the genomic and biological characteristics of a ToYVSV isolate (Ba3) from a potato plant sampled in Rio Grande do Sul State, Brazil. The DNA-A nucleotide sequence of Ba3 and another previously reported ToYVSV isolate share 89.7% sequence identity. These ToYVSV isolates should be classified as a new species in that they are most closely related to Soybean blistering mosaic virus with which they share only ~80% identity. Cloned constructs containing 1.5 mer copies of the ToYVSV genomic components were found, by biolistic bombardment, to be infectious in at least 11 plant species in 2 families (Solanaceae and Malvaceae). Symptoms on tomato and potato plants were identical to those originally observed on field-infected plants. ToYVSV was also sap-transmissible from Nicotiana benthamiana to N. benthamiana and tomato, but not to potato plants. © 2009 Springer Science+Business Media, LLC.
Pineli L.L.O.,University of Brasilia |
Moretti C.L.,Embrapa Vegetables |
Chiarello M.D.,Catholic University of Brasília
Journal of Food, Agriculture and Environment | Year: 2012
Oxidative stress is a major issue in human health. It is usually associated with an increase in the generation of free radicals and the inability of biological systems to tackle this disequilibrium. Antioxidants from fruits and vegetables are considered an important protection factor against oxidative stress and its deleterious consequences to human health. We evaluated quality and bioactive compounds and antioxidant characteristics of 'Osogrande' and 'Camino Real' strawberries grown in the Brazilian savannah. Strawberries were harvested, selected, graded and stored at 5°C and 15°C for eight days. Berries were evaluated for vitamin C, total phenolic compounds, total anthocyanins, total ellagic acid, antioxidant activity by DPPH and FRAP assays, decay, mass loss, color, soluble solids and total titratable acidity. An increase in total phenolic compounds content ranging from 64% to 79% was observed for both cultivars at both temperatures between the fourth and the sixth days. 'Camino Real' strawberries showed higher contents at 15°C in the sixth day of the experiment. 'Osogrande' strawberries had the highest concentrations of total ellagic acid. Vitamin C content increased in all treatments when berries were stored at 15°C. No significant changes in antioxidant activity assayed by DPPH were observed for 'Osogrande' strawberries stored at 5°C. Antioxidants of strawberries were comparable to those of fruit grown in other locations. After 2 days of storage only 'Camino Real' strawberries at 5°C presented acceptable (>3.0) quality index. For fruits stored at 5°C, decay was dramatically observed between the second and the fourth storage days, when 32% and 40% of 'Osogrande' and 'Camino Real' fruit surfaces were affected, respectively. Firmness of 'Camino Real' strawberries was approximately 2 times higher than 'Osogrande' fruits throughout the experimental period. Titratable acidity in 'Camino Real' strawberries decreased 19.5% and 17.4% after eight days at 5°C and 15°C, respectively. For 'Osogrande' fruits hue angle increased after four days, indicating a decrease in redness. Chroma did not change during storage time for both cultivars. The results of this study showed that antioxidant variables were not good markers of strawberry quality, given that they were positively related to decay variables.
Moretti C.L.,Embrapa Vegetables |
Mattos L.M.,Embrapa Vegetables |
Calbo A.G.,Embrapa Agricultural Instrumentation |
Sargent S.A.,University of Florida
Food Research International | Year: 2010
Temperature increase and the effects of greenhouse gases are among the most important issues associated with climate change. Studies have shown that the production and quality of fresh fruit and vegetable crops can be directly and indirectly affected by high temperatures and exposure to elevated levels of carbon dioxide and ozone. Temperature increase affects photosynthesis directly, causing alterations in sugars, organic acids, and flavonoids contents, firmness and antioxidant activity. Carbon dioxide accumulation in the atmosphere has directly effects on postharvest quality causing tuber malformation, occurrence of common scab, and changes in reducing sugars contents on potatoes. High concentrations of atmospheric ozone can potentially cause reduction in the photosynthetic process, growth and biomass accumulation. Ozone-enriched atmospheres increased vitamin C content and decreased emissions of volatile esters on strawberries. Tomatoes exposed to ozone concentrations ranging from 0.005 to 1.0 μmol/mol had a transient increase in β-carotene, lutein and lycopene contents. © 2009 Elsevier Ltd.
Barreto S.S.,University of Brasilia |
Hallwass M.,Embrapa Vegetables |
Aquino O.M.,Embrapa Vegetables |
Inoue-Nagata A.K.,Embrapa Vegetables
Phytopathology | Year: 2013
Tomato severe rugose virus (ToSRV) is the most important begomovirus species in Brazilian tomato production. Many weeds are associated with tomato, and some are hosts of begomoviruses. Only one species of weed, Nicandra physaloides, has been found to be infected with ToSRV. In this study, four weed species were investigated for their capacity to be infected by ToSRV and serve as a potential source of inoculum for tomato. Begomoviruses from naturally infected Crotalaria spp., Euphorbia heterophylla, N. physaloides, and Sida spp. were successfully transferred to tomato plants by biolistic inoculation. ToSRV was the major virus transferred to tomato. In contrast, other begomoviruses were transferred to weeds, such as Sida micrantha mosaic virus and Euphorbia yellow mosaic virus. Furthermore, a new strain of Sida micrantha mosaic virus is reported. We also confirmed that Crotalaria spp., E. heterophylla, and Sida spp. are infected with ToSRV but at low viral titers and in mixed infections with weed-infecting begomoviruses. Thus, it was demonstrated that weeds are potential sources of ToSRV for tomato in central Brazil. © 2013 The American Phytopathological Society.
Nascimento W.M.,Embrapa Vegetables |
Huber D.J.,University of Florida |
Cantliffe D.J.,University of Florida
Seed Science and Technology | Year: 2013
Carrot (Daucus carota) seed germination and consequently stand establishment may be reduced at temperatures above 35°C. Priming circumvents thermoinhibition in several species, including carrot. Seeds from a thermosensitive population ('07 EC-403', Nunhems) were produced under Florida (USA) field conditions from March to July using artificial vernalised roots. Secondary umbels were labeled at anthesis. At 20, 30 and 40 days after anthesis (DAA), umbels were harvested, dried and manually processed. Part of the seed batch was primed in an aerated polyethylene glycol (PEG) (30%) solution at 15°C for 0, 3, 6 and 9 days, under light. Seed respiration (CO2 production) and germination at 20 and 35°C were evaluated after priming. At 20°C, there was 88, 95 and 95% germination of non-primed seeds from umbels harvested at 20, 30 and 40 DAA, respectively, while at 35°C, there was only 4, 13 and 28% germination, respectively. Seed germination and CO2 production increased in response to seed maturity and soak duration. For example, seeds from umbels harvested at 40 DAA and primed for nine days germinated 98 and 89% at 20 and 35°C, respectively. These seeds also exhibited higher respiration rates. To improve stand establishment, especially during periods of high temperatures, carrot seeds must be primed for a period of nine days.
Luengo R.F.A.,Embrapa Vegetables |
Calbo A.G.,Embrapa Instrumentation
Acta Horticulturae | Year: 2016
Vegetables need to be graded ('classified') according to agreed standards for each product in the market. The purpose of classification is to provide the seller and the buyer with a language, valid and safe, to enable agile negotiation of prices. In virtual commercialization, using digital communication tools, classification is no longer optional: it is indispensable. Classification prevents rework and misunderstandings related to inferior products with injuries and defects that induce contamination and losses associated with product disposal or reductions in sales value. In the Brazilian Federal District, as well as in other areas of Brazil, we observed that growers sell their vegetables, in most instances, without doing the work of sorting the product, a lack of investment that reduces their business performance. The perceived savings, in these cases, however, are transferred to the buyers who offer lower prices. The procedure as a whole is slower, involves rework and can cause increased costs and losses away from the farm, besides some reduction in freshness. In this work, 30 producers of typical vegetables of the Federal District, 75% of whom trade their vegetables without the use of classification, were studied. The possibility of using simple classification with minimal handling, using packaging containers arranged on a transporter was demonstrated. The proposed sorting alternative indicated that more growers could start sorting their vegetables for commercialization and achieve better profitability.
Pineli L.D.L.D.O.,University of Brasilia |
Moretti C.L.,Embrapa Vegetables |
dos Santos M.S.,Catholic University of Brasília |
Campos A.B.,Catholic University of Brasília |
And 3 more authors.
Journal of Food Composition and Analysis | Year: 2011
The present work evaluated the quality and antioxidant characteristics of 'Osogrande' and 'Camino Real' strawberries at different ripeness stages. Strawberries (Fragaria x ananassa Duch.) were harvested, selected, graded according to ripeness (green, pink or 3/4 ripe and ripe) and evaluated for pH, total soluble solids, total titratable acidity, sugar/acid ratio, vitamin C, total phenolic compounds, total ellagic acid, total and individual anthocyanins and antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP). The highest total soluble solid content was found for pink (7.5° Brix) and ripe (7.9° Brix) 'Osogrande' strawberries. At pink stage, this cultivar showed higher amounts of total phenolics (2909.48mgkg-1FW) and total ellagic acid (454.16mgkg-1FW). Pink 'Camino Real' strawberries presented the highest content of vitamin C (528.55mgkg-1FW). Antioxidant activity was higher for 'Osogrande' cultivar, at green stage, according to DPPH (11.91μmolBHTg-1FW) and FRAP (36.75μmolferrous sulphate g-1FW) assays and at ripe stage, only for DPPH assay (12.83μmolBHTg-1FW). Anthocyanins increased along ripening, with more elevated concentrations in ripe 'Camino Real' strawberries (292.9mgkg-1FW). Cyanindin-3-glucoside showed a higher concentration for the same treatment (17.23mgkg-1FW), which might contribute to a more redish color. Although ripe berries have a better flavor and are more appreciated, higher antioxidant contents and activities were observed at pink stage in which higher amounts of total phenolics, total ellagic acid and vitamin C were noticed for both cultivars. © 2010 Elsevier Inc.
Togni P.H.B.,University of Brasilia |
Laumann R.A.,Biological Control |
Medeiros M.A.,Embrapa Vegetables |
Sujii E.R.,Biological Control
Entomologia Experimentalis et Applicata | Year: 2010
The silverleaf whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is one of the most important pest insects in tomato crop systems worldwide. It has been previously demonstrated that intercropping tomato [Solanum lycopersicum L. Mill. (Solanaceae)] with coriander [Coriandrum sativum L. (Apiaceae)] reduces the incidence and severity of damage caused by B. tabaci. However, it is not yet known how coriander affects the insect′s behaviour. We evaluated the attractiveness of tomato constitutive volatiles to B. tabaci and what effect coriander constitutive volatiles have on the insect′s behaviour. To this end, we conducted three bioassays in a multiple-choice four-arm olfactometer ('×' type), measuring B. tabaci behaviour when offered tomato and coriander constitutive volatiles presented alone as well as together. We also evaluated the colonisation and establishment of B. tabaci in experimental plots with only single tomato plants and tomatoes intercropped with coriander in a greenhouse. Bemisia tabaci males and females recognised tomato constitutive volatiles as a positive stimulus (kairomonal effect), indicating that semiochemicals from this plant can play an important role in the insect's host plant selection. Coriander constitutive volatiles reduced the attractiveness of tomato volatiles but no repellency to these volatiles was observed. Greater numbers of adults and nymphs of B. tabaci per plant were observed in tomato monoculture plots than in tomato intercropped with coriander. We suggest that coriander constitutive volatiles have an odour masking effect on tomato volatiles, thus interfering in the host plant selection of B. tabaci. © 2010 Agriculture and Agri-Food Canada. Journal compilation © 2010 The Netherlands Entomological Society.
Nicolini C.,State University of Piauí |
Inoue-Nagata A.K.,Embrapa Vegetables |
Nagata T.,University of Brasilia
Archives of Virology | Year: 2014
In a previous work, a distinct tymovirus infecting tomato plants in Brazil was reported and tentatively named tomato blistering mosaic virus (ToBMV). In this study, the complete genome sequence of ToBMV was determined and shown to have a size of 6277 nucleotides and three ORFs: ORF 1 encodes the replication-complex polyprotein, ORF 2 the movement protein, and ORF 3 the coat protein. The cleavage sites of the replication-complex polyprotein (GS/LP and VAG/QSP) of ToBMV were predicted by alignment analysis of amino acid sequences of other tymoviruses. In the phylogenetic tree, ToBMV clustered with the tymoviruses that infect solanaceous hosts. © 2014, Springer-Verlag Wien.