Herbicide application on Genetically Modified Maize influences bee visitation

Brazil is one of the world’s largest producers of maize (Zea mays L.). Cry proteins derived from the bacterium Bacillus thuringiensis (Bt) have been widely used in transgenic maize due to their toxicity and specificity against insects that damage crops. In addition, these plants have been stacked with different herbicide tolerance genes. Non-target insects end up being exposed to Bt proteins and herbicide applications. There is little information on the effects of Bt transgenics and their cultural practices on the behavior of pollinators in genetically modified crops. The aim of this research was to verify the impact of genotypes of genetically modified maize, Herculex®, PowerCore®, and the conventional isohybrid, pulverized or not with herbicides (atrazine, glufosinate-ammonium and nicosulfuron) in bee populations. In order to evaluate the presence of insects, a zig-zag tour was carried out throughout the experimental field, ascertained from visual analysis and direct counting of six plants per plot (the dimensions of the plots were 2.5 x 10 m with five maize lines spaced 0.50 m between rows and 0.36 m between plants) randomly, 18 days after spraying herbicides in the area. Apis mellifera (L.) (Hymenoptera: Apidae), Tetragonisca angustula (L.) (Hymenoptera: Apidae) and Trigona spinipes (F.) (Hymenoptera: Apidae) were the pollinator species identified in the crop. It was observed that the incidence of pollinator insects varied according to cultivars and herbicides tested; however, the PowerCore® genotype experienced more visitation of pollinating bees independently of the herbicide treatments.

Biological aspects of Podisus nigrispinus (Hemiptera: Pentatomidae) with Spodoptera frugiperda (Lepidoptera: Noctuidae) prey fed on transgenic maize genotypes

?rea de concentra??o: Produ??o Vegetal.Uma importante preocupa??o em rela??o ao uso de plantas geneticamente modificadas (GMs) que expressam toxinas inseticidas do Bacillus thuringiensis (Bt), ? o poss?vel efeito prejudicial em organismos n?o alvos. O percevejo predador Podisus nigrispinus (Dallas) (Hemiptera: Pentatomidae) ? utilizado como agente de controle biol?gico e pode ser exposto ? toxinas Bt. Este estudo teve como objetivo analisar o movimento das diferentes prote?nas Cry em P. nigrispinus predando lagartas de Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), alimentadas em gen?tipos de milho Bt, bem como o desenvolvimento, a capacidade predat?ria, reprodutiva e poss?veis altera??es nas c?lulas do intestino m?dio desse inimigo natural. O experimento foi realizado em delineamento inteiramente casualizado com tr?s tratamentos i) Isoh?brido (n?o Bt), ii) Herculex? (milho transg?nico que codifica a prote?na Cry1F) e iii) PowerCore? (milho transg?nico piramidado que codifica as prote?nas Cry1F, Cry1A.105 e Cry2Ab2), com 14 repeti??es cada. Lagartas de S. frugiperda com dez dias foram individualizadas e alimentadas ad libitum com folhas de milho transg?nico Herculex?, PowerCore? ou Isoh?brido durante 48 horas. F?meas de P. nigrispinus com 72 horas de vida foram alimentadas, diariamente, por tr?s dias com uma S. frugiperda ap?s alimenta??o em milho Bt ou Isoh?brido. Posteriormente, P. nigrispinus foram crioanestesiados e dissecados sob estereomicrosc?pio para remo??o do sistema digest?rio. A presen?a de prote?nas Cry, ganho de biomassa, biomassa consumida (preda??o), per?odo de oviposi??o, n?mero de posturas, n?mero de ovos, n?mero de ovos por postura, n?mero de ninfas, viabilidade dos ovos, per?odo embrion?rio, longevidade das f?meas e desenvolvimento ninfal foram avaliados. Os resultados mostram que diferentes prote?nas Cry se movem atrav?s da cadeia alimentar de P. nigrispinus e fornecem evid?ncias de que a ingest?o de tr?s diferentes prote?nas n?o leva a efeitos sin?rgicos inesperados. No entanto, as toxinas Cry promoveram altera??es histol?gicas nas c?lulas do intestino m?dio de P. nigrispinus.Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Produ??o Vegetal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2019.An important concern regarding the use of genetically modified plants (GMs) expressing Bacillus thuringiensis (Bt) insecticidal toxins, is the possible deleterious effect on non-target organisms. The predatory stink Podisus nigrispinus (Dallas) (Hemiptera: Pentatomidae) is used as a biological control agent and can be exposed to Bt toxins. The objective of this study was to analyze the movement of different Cry proteins in P. nigrispinus by predating Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae) caterpillars fed on Bt maize genotypes, as well as the development, predatory and reproductive capacity and possible changes in the cells of the midgut of this natural enemy. The experiment was carried out in a completely randomized design with three treatments: i) Isohybrid (not Bt), ii) Herculex? (transgenic corn encoding Cry1F protein) and iii) PowerCore? (pyramid transgenic maize encoding the Cry1F, Cry1A.105 and Cry2Ab2 proteins), with 14 replicates each. Ten-day S. frugiperda caterpillars were individualized and fed ad libitum with Isohybrid, Herculex? or PowerCore? maize leaves for 48 hours. Twenty-two-hour-old P. nigrispinus females were fed daily for three days with a S. frugiperda after contact with Bt or Isohybrid maize. Subsequently, P. nigrispinus after predation were cryoanesthetized and dissected under stereomicroscope for removal of the digestory system. The presence of Cry proteins, consumed prey biomass (predation), oviposition period, number of postures, number of eggs, number of eggs per posture, number of nymphs, egg viability, embryonic period, female longevity and development and survival rates of immature were evaluated. The results show that different Cry proteins move through the food chain of P. nigrispinus and provide evidence that the ingestion of three different proteins does not lead to unexpected synergistic effects. However, Cry toxins promoted histological changes in the cells of the midgut of P. nigrispinus

Evaluation of transgenic sweet orange (Citrus sinensis L. Osbeck) overexpressing the CDR-1, PDF2.2, or GLT1 gene for resistance to Xanthomonas citri subsp. citri or Candidatus Liberibacter asiaticus

A citricultura está sujeita a distintos desafios, em especial, à ameaça de diversas doenças de alto impacto destrutivo, a exemplo do cancro cítrico (Xanthomonas citri subsp. citri) (Xcc) e do Greening ou Huanglongbing (HLB) (Candidatus Liberibacter spp.) (CLas). A engenharia genética de plantas cítricas é uma abordagem atraente na busca de materiais superiores, pois pode resultar em um rápido desenvolvimento de cultivares resistentes a doenças. Dessa forma, plantas de laranja \'Hamlin\' (Citrus sinensis L. Osbeck) previamente transformadas para a superexpressão do gene CDR-1 (constitutive disease resistance protein 1) ou PDF2.2 (pathogenesis-related proteins 12) ou GLT1 (plastidic glucose transporter 1), foram avaliadas para potenciais efeitos de resistência ao cancro cítrico ou ao HLB. Dezessete eventos CDR-1 foram multiplicados a partir de borbulhas de plantas matrizes em porta-enxertos de limão \'Cravo\' (C. limonia Osbeck) e inoculados por aspersão com uma suspensão de Xcc. Nenhum evento transgênico apresentou reduções na incidência e severidade dos sintomas de cancro cítrico em comparação com as plantas não transgênicas (WT1), 35 dias após a inoculação. Entretanto, no primeiro bioensaio, a incidência e a severidade da doença foram maiores em alguns eventos superexpressando o gene CDR-1. Supõe-se que a resposta de hipersensibilidade (HR) que envolve uma necrose rápida de células infectadas e a formação de lesões pode ter sido potencializada pela superexpressão deste gene, e ter contribuído para a colonização de Xcc. Embora nenhum dos eventos CDR-1 ou PDF2.2 tenham apresentado menor incidência ou severidade quando comparados com as plantas não transgênicas, é possível que as menores populações bacterianas, número e área média de lesões, além de maiores teores de H2O2 e clorofila em alguns materiais possam auxiliar no manejo da doença em áreas de exclusão ou erradicação. Em outro experimento, dez eventos superexpressando o gene GLT1 foram inoculados com borbulhas infectadas com CLas, bactéria associada ao HLB. A infecção com CLas acarretou na elevação das concentrações de glicose, frutose e de amido em plantas não transgênicas (WT). Embora nenhum dos eventos GLT1 apresente características de resistência ao HLB quando comparados com as plantas WT, é possível que os menores valores de Cycle threshold (CT) e populações bacterianas, associados também a menores concentrações de açúcares solúveis, bons parâmetros para trocas gasosas e macro e micronutrientes em alguns eventos, possam contribuir para um melhor desenvolvimento das plantas infectadas.Citriculture is subject to different challenges, in particular, the threat of various diseases with a highly destructive impact, such as citrus canker (Xanthomonas citri subsp. citri) (Xcc) and Greening or Huanglongbing (HLB) (Candidatus Liberibacter spp.) (CLas). Genetic engineering of citrus plants is an attractive approach in the search for superior materials, as it can result in the rapid development of disease-resistant cultivars. Thus, plants of \'Hamlin\' orange (Citrus sinensis L. Osbeck) previously transformed for overexpression of the gene CDR-1 (constitutive disease resistance protein 1) or PDF2.2 (pathogenesis-related proteins 12) or GLT1 (plastidic glucose transporter 1), were evaluated for potential effects of resistance to citrus canker or HLB. Seventeen CDR-1 events were multiplied from buds of parent plants on \'Rangpur\' lemon rootstocks (C. limonia Osbeck) and inoculated by spraying with an Xcc suspension. No transgenic event showed reductions in the incidence and severity of citrus canker symptoms compared to non-transgenic plants (WT1) 35 days after inoculation. However, in the first bioassay, the incidence and severity of the disease were higher in some events overexpressing the CDR-1 gene. It is hypothesized that the hypersensitivity response (HR), which involves rapid necrosis of infected cells and the formation of lesions, may have been potentiated by the overexpression of this gene, and have contributed to the colonization of Xcc. Although none of the CDR-1 or PDF2.2 events showed lower incidence or severity when compared to non-transgenic plants, it is possible that lower bacterial populations, average number and area of lesions, in addition to higher H2O2 and chlorophyll contents in some materials can help in the management of the disease in areas of exclusion or eradication. In another experiment, ten events overexpressing the GLT1 gene were inoculated with buds infected with CLas, bacteria associated with HLB. Infection with CLas led to increased concentrations of glucose, fructose, and starch in non-transgenic (WT) plants. Although none of the GLT1 events show characteristics of resistance to HLB when compared to WT plants, it is possible that the lower Cycle threshold (CT) values and bacterial populations, also associated with lower concentrations of soluble sugars, are good parameters for gas exchange and macro and micronutrients in some events, may contribute to better development of infected plants

Resumos concluídos - Nanomateriais

Resumos concluídos - Nanomateriai