A inoculação e coinoculação do arroz de terras altas com rizobactérias multifuncionais pode promover o crescimento das plantas, especialmente do sistema radicular. Assim, este estudo teve como ...objetivo avaliar o efeito da inoculação e coinoculação com Azospirillum sp. e Bacillus sp. no desenvolvimento inicial do arroz de terras altas. O experimento foi conduzido em delineamento inteiramente casualizado com 4 tratamentos e 10 repetições, totalizando 40 parcelas. Os tratamentos foram: 1) Ab-V5 (Azospirillum brasilense), 2) BRM 63573 (Bacillus sp.), 3) coinoculação de Ab-V5 + BRM 63573 e 4) controle (sem rizobactérias). A inoculação e coinoculação com as rizobactérias multifuncionais Ab-V5 e BRM 63573 proporcionaram efeitos positivos no desenvolvimento inicial do arroz de terras altas. A inoculação com o isolado BRM 63573 teve efeitos significativos no comprimento da raiz, parte aérea e biomassa total, enquanto a inoculação com o isolado Ab-V5 teve efeitos significativos no comprimento da raiz e produção de raiz e biomassa total. O tratamento com coinoculação teve efeitos significativos em variáveis como diâmetro, volume e superfície total de raiz e biomassa de raiz e total. O tratamento controle (sem rizobactérias multifuncionais) apresentou os piores resultados para a maioria das variáveis analisadas.
The cotton boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), is one of the most important insect pests of cotton, causing significant yield losses. This insect completes ...its life cycle only on the flower structures of some Malvaceae species, with cotton being its preferred host. However, during the cotton off‐season, the boll weevil enters a reproductive dormancy state, in tropical regions, with important alterations in their reproduction organs. During this period, a remaining insect population survives feeding on a variety of other food sources, but the insects do not reproduce. We hypothesized that these alterations in the insect's reproductive organs are associated with the nutritional levels provided by alternative food sources during the cotton off‐season. To test our hypothesis, we first investigated food sources that sustain insect survival for long periods, such as weed species and fruits of cultivated crops. Then, we evaluated how various food sources affect the reproductive organs and reproductive capacity of the boll weevil. Among the alternative food sources tested, insect longevity was highest on banana (Musa paradisiaca L.), mango (Mangifera indica L.), papaya (Carica papaya L.), milkweed (Euphorbia heterophylla L.), and lilac tasselflower (Emilia sonchifolia L.). However, only banana and mango resulted in greater longevity than cotton squares. Banana was the preferred food and resulted in the highest levels of nutrients in the insects. Additionally, insects previously fed on banana made more oviposition punctures on cotton squares than those fed only on cotton squares, which resulted in a significantly higher number of emerged adults. Histological analysis of the insects' reproductive organs showed that feeding on papaya resulted in morphological changes and testicle degradation. In conclusion, we present evidence that boll weevils fed on alternative food sources (other than cotton squares or similar‐quality food) display a nutritional imbalance, associated with substantial alterations in the reproductive tissues of this insect, which may trigger the reproductive dormancy state.
Anthonomus grandis (Coleoptera: Curculionidae) feeds preferentially on cotton and completes its cycle only on a few plants of the Malvaceae family. However, this insect survives the cotton off‐season period feeding on other plant species, such as cultivated fruits or weed flowers. These insects survived longer and preferred banana over cotton squares. When they fed on low‐nutritional food (e.g., papaya fruit), their reproductive organs (testicles and oocytes) showed an abnormal morphology, which impaired their ability to lay viable eggs.
The aim of our study was to produce and characterize poly-ε-caprolactone (PCL) nanospheres containing essential oils from
fruit and to evaluate their stability gains as well as their insecticidal and ...deterrent activities against whitefly (
). The PCL nanospheres exhibited a homogeneous spherical morphology, with particle diameters between 106.7 nm and 129.2 nm, pH of approximately 6, zeta potential (ZP) lower than -19.0 mV and encapsulation efficiency higher than 98%. Only 43% of the nanoencapsulated essential oil (NSEO) was degraded in response to ultraviolet light, whereas the essential oil (EO) degraded by 76% over the same period. In a free-choice test, the NSEO and EO reduced the number of whitefly eggs by approximately 70%. NSEO and EO at 1.5% killed 82.87% and 91.23% of 2nd-instar nymphs of whitefly, respectively. Although NSEO displayed lower insecticidal activity, it offers a greater advantage over the free EO, due to protection conferred by polymer against photodegradation. Therefore, its usage may optimize the maintenance of essential oils in the field through photoprotection and controlled release. Our results suggest that the EO of
fruit can be used for
management strategy; nevertheless, the benefits of NSEO require further evaluation at the field level.
In Brazil, the Cowpea mild mottle virus vectored by Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae), is an emerging threat for common bean (Phaseolus vulgaris L.; Fabaceae), including genetically ...modified elite bean lines developed for resistance to the Bean golden mosaic virus. To investigate this interaction, we quantified the susceptibility of 10 Bean golden mosaic virus-resistant lines to Cowpea mild mottle virus infection in 2 regions in Brazil with natural incidence of viruliferous B. tabaci. In 2 field trials, B. tabaci established on all varieties, but showed preference for the conventional cultivars ‘Pérola’ and ‘BRS Pontal’ when compared with elite lines (averaging > 400 nymphs per leaflet, and > 97% infection rate in 1 study). However, whereas elite lines were resistant to Bean golden mosaic virus, all became infected with Cowpea mild mottle virus. Highest infection rates (19 to 99% infected plants) occurred in genetically modified elite lines derived from BRS Pontal versus Pérola (12 to 16%). When comparing seed yield, most elite lines outperformed their conventional recurrent parent. On average, elite lines achieved relative yield increases between 199 and 1,045%, and the varieties CNFCT 16205 and CNFCT 16210 were the most productive in our field trials. Our results showed that the use of common bean cultivars resistant to golden mosaic is an important tool within integrated management strategies for whiteflies and viruses. However, further studies are needed to elucidate the threat of Cowpea mild mottle virus and the nature of whitefly interactions between these different viruses. No Brasil, o Cowpea mild mottle virus transmitido pela Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae), é uma ameaça emergente ao feijão comum (Phaseolus vulgaris L.; Fabaceae), incluindo as linhas elites de feijão geneticamente modificadas desenvolvidas para resistência ao Bean golden mosaic virus. Para investigar essa interação, quantificamos a suscetibilidade de dez linhas geneticamente modificadas resistentes ao Bean golden mosaic virus à infecção pelo Cowpea mild mottle virus em duas regiões do Brasil com incidência natural de B. tabaci virulíferas. Em dois ensaios de campo, B. tabaci estabeleceu em todas as variedades, mas mostrou preferência pelas cultivares convencionais ‘Pérola’ e ‘BRS Pontal’ quando comparadas com as linhas elite geneticamente modificadas (média > 400 ninfas por folíolo e > 97% taxa de infecção por virus em um dos estudos). No entanto, embora as linhas elite foram resistentes ao Bean golden mosaic virus, todas foram infectadas pelo Cowpea mild mottle virus. As maiores taxas de infecção (19 a 99% de plantas infectadas) ocorreram nas linhas elite geneticamente modificadas derivadas da BRS Pontal versus Pérola (12 a 16%). Ao comparar a produtividade, a maioria das linhas elite superou seu pai convencional recorrente. Os aumentos relativos de rendimento foi de 199 a 1.045% sendo as variedades CNFCT 16205 e CNFCT 16210 as mais produtivas. Nossos resultados mostraram que o uso de cultivares de feijão resistentes ao mosaico dourado é uma ferramenta importante dentro das estratégias integradas de manejo para moscas-brancas e vírus. No entanto, mais estudos são necessários para elucidar à ameaça do Cowpea mild mottle virus e a natureza das interações da mosca-branca com estes diferentes vírus.
Common bean (
Phaseolus vulgaris
L.) is a staple food in Brazil with both nutritional and socioeconomic importance. As an orphan crop, it has not received as much research attention as the commodity ...crops. Crop losses are strongly related to virus diseases transmitted by the whitefly
Bemisia tabaci
, one of the most important agricultural pests in the world. The main method of managing whitefly-transmitted viruses has been the application of insecticides to reduce vector populations. Compared to chemical vector control, a more sustainable strategy for managing insect-borne viruses is the development of resistant/tolerant cultivars. RNA interference has been applied to develop plant lines resistant to the whitefly in other species, such as tomato, lettuce and tobacco. Still, no whitefly-resistant plant has been made commercially available to date. Common bean is a recalcitrant species to
in vitro
regeneration; therefore, stable genetic transformation of this plant has been achieved only at low frequencies (<1%) using particle bombardment. In the present work, two transgenic common bean lines were obtained with an intron-hairpin construct to induce post-transcriptional gene silencing against the
B. tabaci vATPase
(Bt-
vATPase
) gene, with stable expression of siRNA. Northern blot analysis revealed the presence of bands of expected size for siRNA in leaf samples of the line Bt-22.5, while in the other line (11.5), the amount of siRNA produced was significantly smaller. Bioassays were conducted with both lines, but only the line Bt-22.5 was associated with significant mortality of adult insects (97% when insects were fed on detached leaves and 59% on the whole plant). The expression of the Bt-
vATPase
gene was 50% lower (
p
< 0.05) in insects that fed on the transgenic line Bt-22.5, when compared to non-transgenic controls. The transgenic line did not affect the virus transmission ability of the insects. Moreover, no effect was observed on the reproduction of non-target organisms, such as the black aphid
Aphis craccivora
, the leafminer
Liriomyza
sp. and the whitefly parasitoid
Encarsia formosa
. The results presented here serve as a basis for the development of whitefly-tolerant transgenic elite common bean cultivars, with potential to contribute to the management of the whitefly and virus diseases.
ABSTRACT The use of beneficial microorganisms in crop systems can contribute to sustainable agriculture by promoting improvements in crop development and grain yield without damaging the environment. ...However, there is much uncertainty surrounding the effects of using a combination of microorganisms to promote plant development. The objective of this work was to determine the effects of microorganism species individually and in combination on the biomass production, gas exchange and nutrient contents in the shoots and roots of soybean plants. The experimental design was completely randomized, with 30 treatments and three replicates. The treatments consisted of the application of the rhizobacteria BRM 32109, BRM 32110 and 1301 (Bacillussp.); BRM 32111 and BRM 32112 (Pseudomonas sp.); BRM 32113 (Burkholderia sp.); BRM 32114 (Serratia sp.); Ab-V5 (Azospirillum bras ilense) and 1381 (Azospirillum sp.); the fungus Trichoderma asperellum (a mixture of the isolates UFRA. T06, UFRA. T09, UFRA. T12 and UFRA. T52); 19 combinations of these microorganisms, and a control (no microorganisms). At sowing, the soil was treated with Bradyrhizobium, and then the soybean seeds were inoculated. The microorganism suspension was applied in each treatment at 7 days after planting (DAP) in the soil and at 21 DAP on the seedlings. The Trichoderma pool, Ab-V5, 1301 + 32110, 1301 + 32114, 1301 + Ab-V5 and 32110 + Ab-V5 treatments resulted in significantly higher total biomass accumulation in the soybean plants, with values that were, on average, 25% higher than that in the control treatment. Our results suggest that the use of beneficial microorganisms in cropping systems is a promising technique.
RESUMO O uso de microrganismos benéficos nos sistemas de cultivo pode contribuir para a agricultura sustentável, promovendo melhorias no desenvolvimento das culturas e na produção de grãos sem danificar o meio ambiente. No entanto, há muita incerteza quanto aos efeitos do uso de uma combinação de microrganismos para promover o desenvolvimento da planta. O objetivo deste trabalho foi determinar os efeitos das espécies de microrganismos individualmente e em combinação na produção de biomassa, trocas gasosas e conteúdo de nutrientes na parte aérea e raízes das plantas de soja. O delineamento experimental foi inteiramente casualizado, com 30 tratamentos e três repetições. Os tratamentos consistiram na aplicação das rizobactérias BRM 32109, BRM 32110 e 1301 (Bacillus sp.); BRM 32111 e BRM 32112 (Pseudomonas sp.); BRM 32113 (Burkholderia sp.); BRM 32114 (Serratia sp.); Ab-V5 (Azospirillum brasilense) e 1381 (Azospirillum sp.); o fungo Trichoderma asperellum (uma mistura dos isolados UFRA. T06, UFRA. T09, UFRA. T12 e UFRA. T52); 19 combinações desses microrganismos e um controle (sem microrganismos). Na semeadura, o solo foi tratado com Bradyrhizobium e as sementes de soja foram inoculadas. A suspensão de microrganismos foi aplicada em cada tratamento aos 7 dias após o plantio (DAP) no solo e aos 21 DAP nas mudas. Os tratamentos pool de Trichoderma, Ab-V5, 1301 + 32110, 1301 + 32114, 1301 + Ab-V5 e 32110 + Ab-V5 resultaram em acúmulo de biomassa total significativamente maior nas plantas de soja, com valores, em média, 25% superior ao tratamento controle. Nossos resultados sugerem que o uso de microrganismos benéficos em sistemas de cultivo é uma técnica promissora.
Entomopathogenic fungi stand out in the biological control of several agriculturally important insects. Six isolates of Metarhizium anisopliae, Cordyceps javanica, Beauveria sp. and B. bassiana were ...screened to control Anthonomus grandis, Euschistus heros, Oebalus poecilus, O. ypsilongriseus and Thyanta perditor, important insect pests of soybean, cotton and rice. The bioassays were conducted in a completely randomized design, with four replications (10 insects/replication). Significant differences for virulence were observed between the tested fungal species and isolates. For A. grandis, the most virulent isolate was M. anisopliae BRM 2335, followed by Beauveria BRM 14527 and BRM 67744 82.5 to 97.5 % of mortality; average lethal time (LT50) of 5.9 to 7.8 days. M. anisopliae BRM 2335 was also highly virulent to the four stink bug species (75 to 97.5 % of mortality; LT50 of 5.2 to 9.7 days). For the stink bugs, Beauveriasp. BRM 67744 was infectious to O. poecilus (75 % of mortality), but failed to control E. heros (16.9 % of mortality). C. javanicaBRM 27666 and BRM 14526 showed average virulence to the stink bugs and A. grandis (17.5 to 57.3 % of mortality; LT50 of 6.0 to 9.7 days). M. anisopliae was consistently more virulent to the stink bugs than the other fungi. Therefore, M. anisopliaeBRM 2335 was selected for further studies under screenhouse and field conditions to control A. grandis and other stink bug species, especially E. heros.
ABSTRACT Entomopathogenic fungi stand out in the biological control of several agriculturally important insects. Six isolates of Metarhizium anisopliae, Cordyceps javanica, Beauveria sp. and B. ...bassiana were screened to control Anthonomus grandis, Euschistus heros, Oebalus poecilus, O. ypsilongriseus and Thyanta perditor, important insect pests of soybean, cotton and rice. The bioassays were conducted in a completely randomized design, with four replications (10 insects/replication). Significant differences for virulence were observed between the tested fungal species and isolates. For A. grandis, the most virulent isolate was M. anisopliae BRM 2335, followed by Beauveria BRM 14527 and BRM 67744 82.5 to 97.5 % of mortality; average lethal time (LT50) of 5.9 to 7.8 days. M. anisopliae BRM 2335 was also highly virulent to the four stink bug species (75 to 97.5 % of mortality; LT50 of 5.2 to 9.7 days). For the stink bugs, Beauveria sp. BRM 67744 was infectious to O. poecilus (75 % of mortality), but failed to control E. heros (16.9 % of mortality). C. javanica BRM 27666 and BRM 14526 showed average virulence to the stink bugs and A. grandis (17.5 to 57.3 % of mortality; LT50 of 6.0 to 9.7 days). M. anisopliae was consistently more virulent to the stink bugs than the other fungi. Therefore, M. anisopliae BRM 2335 was selected for further studies under screenhouse and field conditions to control A. grandis and other stink bug species, especially E. heros.
RESUMO Os fungos entomopatogênicos destacam-se no controle biológico de diversos insetos de importância agrícola. Seis isolados de Metarhizium anisopliae, Cordyceps javanica, Beauveria sp. e B. bassiana foram selecionados para o controle de Anthonomus grandis, Euschistus heros, Oebalus poecilus, O. ypsilongriseus e Thyanta perditor, importantes insetos-pragas da soja, algodão e arroz. Os bioensaios foram conduzidos em delineamento inteiramente casualizado, com quatro repetições (10 insetos/repetição). Foram observadas diferenças significativas, em termos de virulência, entre as espécies fúngicas e isolados testados. Para A. grandis, M. anisopliae BRM 2335 foi o isolado mais virulento, seguido por Beauveria BRM 14527 e BRM 67744 82,5 a 97,5 % de mortalidade; tempo letal médio (TL50) de 5,9 a 7,8 dias. M. anisopliae BRM 2335 também foi altamente virulento para as quatro espécies de percevejo (75 a 97,5 % de mortalidade; TL50 de 5,2 a 9,7 dias). Para os percevejos, Beauveria sp. BRM 67744 foi infeccioso para O. poecilus (75 % de mortalidade), mas falhou no controle de E. heros (16,9 % de mortalidade). C. javanica BRM 27666 e BRM 14526 apresentaram virulência mediana para os percevejos e A. grandis (17,5 a 57,3 % de mortalidade; TL50 de 6,0 a 9,7 dias). M. anisopliae foi consistentemente mais virulento aos percevejos do que os outros fungos. Portanto, M. anisopliae BRM 2335 foi selecionado para estudos posteriores em casa telada e campo para o controle de A. grandis e outras espécies de percevejo, principalmente E. heros.
Vários fármacos têm sido avaliados para o tratamento da COVID-19, mas somente o antiviral remdesivir foi registrado nos órgãos regulatórios dos principais países desenvolvidos para esse fim. TDF e ...FTC demonstraram atividade contra o SARS-CoV-2 in vitro.
Avaliar a eficácia e toxicidade de TDF e TDF/FTC em pacientes com infecção leve a moderada por COVID-19. Secundariamente, avaliamos biomarcadores de citocinas, quimiocinas e fatores de crescimento celular, associados à fisiopatogenia da COVID-19.
Ensaio clínico randomizado, duplo-cego, controlado por placebo, em pacientes com suspeita clínica de infecção respiratória leve a moderada por SARS-CoV-2. O estudo foi aprovado pela CONEP e registrado no ClinicalTrials.gov. Pacientes foram aleatoriamente recrutados para tomarem TDF (300 mg/dia) ou TDF/FTC (300/200 mg/dia) ou placebo (Vit. C - 500 mg/dia), por 10 dias. O parâmetro primário foi o escore de sintomas e sinais preditivos de COVID-19, avaliado no sétimo dia de acompanhamento dos pacientes.
309 pacientes foram recrutados e 226 foram randomizados nos seguintes grupos: (a) 74 no grupo TDF; (b) 74 no grupo TDF/FTC; e (c) 77 no grupo placebo. Dos 226 pacientes, 139 (62%) foram positivos para o teste RT-PCR para SARS-CoV-2. Febre (≥ 37,8°C), ageusia ou disgeusia, anosmia ou disosmia e dois ou mais sintomas ou sinais clínicos foram significativamente associados com a infecção por SARS-CoV-2. Não houve alteração significativa no escore clínico baseado nos sintomas e sinais clínicos entre os grupos de tratamento. Também não houve diferença quanto aos eventos adversos e eventos adversos graves entre os grupos de tratamentos. Nenhum paciente faleceu durante o período total de 28 dias de acompanhamento do protocolo no estudo. Nos parâmetros secundários, pacientes com infecções respiratórias leve a moderadas por SARS-CoV-2 apresentaram maiores concentrações do fator de crescimento celular e citocinas pró-inflamatórias (G-CSF, IL-1β, IL-6 e TNF-α) em relação aos pacientes sem infecção por SARS-CoV-2.
Febre (≥37,8°C), perda de olfato, perda de paladar e dois ou mais sintomas, têm maior predição para o diagnóstico de COVID-19 leve a moderada. A intervenção farmacológica com TDF ou TDF/FTC não alterou o escore de sintomas e sinais clínicos na infeção respiratória leve a moderada em pacientes com SARS-CoV-2 comparados ao grupo placebo.
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