RESUMO
Pecan (Carya illinoinensis) is one important exotic forest crop cultivated in South America, specifically in Brazil, Uruguay, and Argentina. However, diseases such as anthracnose, favored by high humidity conditions and high summer temperatures, make its cultivation difficult, causing important loss to pecan farmers. This study used morphological and molecular approaches to identify the Colletotrichum species causing anthracnose in pecan plantations in Southern Brazil. The isolates obtained from pecan fruits with anthracnose symptoms were grouped through quantitative morphological characteristics into three distinct morphotypes. Molecular analysis of nuclear genes allowed the identification of six species of Colletotrichum causing anthracnose in pecan: C. nymphaeae, C. fioriniae, C. gloeosporioides, C. siamense, C. kahawae, and C. karsti. Three of these species are reported for the first time as causal agents of anthracnose in pecan. Therefore, these results provide an important basis for the adoption and/or development of anthracnose management strategies in pecan orchards cultivated in southern Brazil and neighboring countries.
Assuntos
Carya , Colletotrichum , Colletotrichum/genética , Brasil , Filogenia , Doenças das PlantasRESUMO
Increased attention is being focused on the biological control of agricultural pests using microorganisms, owing to their potential as a viable substitute for chemical control methods. Insect cadavers constitute a potential source of entomopathogenic microorganisms. We tested whether bacteria and fungi isolated from Spodoptera frugiperda (JE Smith) cadavers could affect its survival, development, egg-laying pattern, and hatchability, as well as induce mortality in Anthonomus grandis Boheman adults. We isolated the bacteria Enterobacter hormaechei and Serratia marcescens and the fungi Scopulariopsis sp. and Aspergillus nomiae from fall armyworm cadavers and the pest insects were subjected to an artificial diet enriched with bacteria cells or fungal spores to be tested, in the case of S. frugiperda, and only fungal spores in the case of A. grandis. Enterobacter hormaechei and A. nomiae were pathogenic to S. frugiperda, affecting the survival of adults and pupae. The fungus Scopulariopsis sp. does not affect the survival of S. frugiperda caterpillars and pupae; however, due to late action, moths and eggs may be affected. Aspergillus nomiae also increased mortality of A. grandis adults, as well as the development of S. frugiperda in the early stages of exposure to the diet, as indicated by the vertical spore transfer to offspring and low hatchability. Enterobacter hormaechei and A. nomiae are potential biocontrol agents for these pests, and warrant further investigation from a toxicological point of view and subsequently in field tests involving formulations that could improve agricultural sustainability practices.
Assuntos
Larva , Controle Biológico de Vetores , Pupa , Spodoptera , Gorgulhos , Animais , Spodoptera/microbiologia , Larva/microbiologia , Gorgulhos/microbiologia , Pupa/microbiologia , Cadáver , Fungos/classificação , Aspergillus , Serratia marcescens , Bactérias/classificação , Bactérias/isolamento & purificação , EnterobacterRESUMO
Two novel members of the subfamily Betarhabdovirinae, family Rhabdoviridae, were identified in Brazil. Overall, their genomes have the typical organization 3'-N-P-P3-M-G-L-5' observed in mono-segmented plant-infecting rhabdoviruses. In aristolochia-associated cytorhabdovirus (AaCV), found in the liana aristolochia (Aristolochia gibertii Hook), an additional short orphan ORF encoding a transmembrane helix was detected between P3 and M. The AaCV genome and inferred encoded proteins share the highest identity values, consistently < 60%, with their counterparts of the yerba mate chlorosis-associated virus (Cytorhabdovirus flaviyerbamate). The second virus, false jalap virus (FaJV), was detected in the herbaceous plant false jalap (Mirabilis jalapa L.) and represents together with tomato betanucleorhabdovirus 2, originally found in tomato plants in Slovenia, a tentative new species of the genus Betanucleorhabdovirus. FaJV particles accumulate in the perinuclear space, and electron-lucent viroplasms were observed in the nuclei of the infected cells. Notably, distinct from typical rhabdoviruses, most virions of AaCV were observed to be non-enclosed within membrane-bounded cavities. Instead, they were frequently seen in close association with surfaces of mitochondria or peroxisomes. Unlike FaJV, AaCV was successfully graft-transmitted to healthy plants of three species of the genus Aristolochia, while mechanical and seed transmission proved unsuccessful for both viruses. Data suggest that these viruses belong to two new tentative species within the subfamily Betarhabdovirinae.
Assuntos
Aristolochia , Mirabilis , Rhabdoviridae , Aristolochia/genética , Mirabilis/genética , Genoma Viral , Plantas/genética , Filogenia , Doenças das PlantasRESUMO
An alarming number of global warnings concerning amphibian mortality outbreaks have been released in recent years. Emerging diseases stand out as the main potential causes. Ranavirus is a worldwide-spread highly infectious disease capable of affecting even other ectothermic animals such as fish and reptiles. One major issue regarding this pathology is the lack of clinical signs before it leads up to death. Aiming at having a better understanding of anurans susceptibility, this study analyzed bullfrog (Lithobates catesbeianus) survival rate, when challenged with three doses of a Brazilian strain of Frog Virus 3 (FV3). The qPCR analysis indicated a low infectivity rate in these animals both as larvae and as adults. To elucidate the results, the following hypothesis was performed: 1) The amount of inoculum used on the frogs was insufficient to trigger an infection; 2) For the FV3 to produce clinical signs in this species, there is the need for a cofactor; 3) The animals did undergo FV3 infection but recovered in the course of the experiment, and 4) The inoculum utilized might have been low-virulence. Finally, the presence of actual clinical signs of ranavirus is discussed, with the more likely hypothesis.(AU)
Um número alarmante de notificações globais sobre surtos de mortalidade de anfíbios tem sido realizado nos últimos anos. As doenças emergentes destacam-se como as principais causas potenciais. O ranavírus é uma doença altamente infecciosa disseminada em todo o mundo, capaz de afetar até outros animais ectotérmicos como peixes e répteis. Uma questão importante em relação a essa patologia é a falta de sinais clínicos antes de levar à morte. Com o objetivo de compreender melhor a suscetibilidade dos anuros, o presente trabalho analisou a taxa de sobrevivência de rãs-touro (Lithobates catesbeianus), desafiadas com três doses de uma estirpe brasileira do Frog virus 3 (FV3). A análise de qPCR indicou baixa taxa de infectividade nesses animais, tanto como larvas quanto como adultos. Procurando esclarecer os resultados, foram formuladas as seguintes hipóteses: 1) A quantidade de inóculo aplicada nas rãs foi insuficiente para desencadear uma infecção; 2) Para que o FV3 dê sinais clínicos nesta espécie, é necessário um cofator; 3) Os animais sofreram infecção por FV3, mas se recuperaram no decorrer do experimento, e 4) O inóculo utilizado pode ter sido de baixa virulência. Finalmente, foi discutida a presença de sinais clínicos reais de ranavírus e levantada a hipótese mais provável(AU)
Assuntos
Animais , Ranavirus/imunologia , Anfíbios/anatomia & histologia , Mortalidade , Iridovirus , Doenças Transmissíveis EmergentesRESUMO
CABMV is a limiting virus for passion fruit crop in Brazil, its main producing country. This virus has been reported in all producing states of the country, with the state of Santa Catarina (SC) in 2017 standing as the third largest passion fruit producer. In 2017, it reached 8.4% of the national production. The southern coast is the main responsible for the increase in production, which has been supplying the domestic market. However, in that same year, this region recorded the first symptom expressions in plants and fruits. The evaluation of the samples collected in the municipalities of Sombrio, Praia Grande and São João do Sul, southern coast of SC, was performed by using a mechanical transmission to indicator plants, PTA-ELISA and RT-PCR, and by sequencing. The evaluation results were positive for CABMV and negative for CMV in PTA-ELISA. In RT-PCR, there was the formation of a 700bp ca band, expected size for Potyvirus, whose sequence comparison with those deposited in GenBank reveled 98% identity with the isolates from São Paulo State. The occurrence of the virus in the southern coast of SC did not reach a serious decrease in passion fruit production due to the union of producers, who adopted preventive management measures to control the virus, whose effect led to a consolidation of the passion fruit production chain in the region.(AU)
O CABMV é um vírus limitante para a cultura do maracujá no Brasil, principal país produtor mundial, cuja ocorrência já foi relatada em todos os estados produtores. Em 2017, o estado de Santa Catarina (SC) foi o terceiro maior produtor de maracujá no Brasil, responsável por 8,4% da produção nacional, sendo o litoral sul o principal responsável pelo aumento da produção, garantindo o abastecimento do mercado interno. Entretanto, nesse mesmo ano, essa região registrou as primeiras expressões de sintomas em plantas e frutos. Uma avaliação das amostras coletadas nos municípios de Sombrio, Praia Grande e São João do Sul, litoral sul de Santa Catarina, foi realizada por transmissão mecânica para plantas indicadoras, PTA-ELISA, RT-PCR e sequenciamento. Os resultados foram positivos para o CABMV e negativos para o CMV, tanto em PTA-ELISA quanto RT-PCR. Na RT-PCR, houve a amplificação de bandas com ca de 700pb, tamanho esperado para o Potyvirus cuja comparação de sequências com as depositadas no GenBank revelaram 98% de similaridade com os isolados do estado de São Paulo. A ocorrência do vírus na região do litoral sul de Santa Catarina não causou quebra na produção de maracujá devido à adoção conjunta de medidas preventivas de manejo pelos produtores, fato que consolidou a cadeia produtiva do maracujá na região.(AU)
Assuntos
Potyvirus/isolamento & purificação , Passiflora/virologia , Brasil , Ensaio de Imunoadsorção Enzimática , Reação em Cadeia da Polimerase , Potyvirus/genéticaRESUMO
Petri disease is complex, attacks young vine plants and it is difficult to be controlled. The fungus Phaeomoniella chlamydospora (Phc) has been identified as the main causative agent of this disease. This study aimed to evaluate the prevalent colonization of the Petri disease fungi in different portions of vine plants; to assess the susceptibility of grapevine rootstocks to the fungus P. chlamydospora; to assess the effect of solarization and biofumigation, followed by hot-water treatment (HWT), on the disinfection of cuttings of the rootstock IAC 766 infected with P. chlamydospora, and assess the effect of solarization and biofumigation, followed by HWT, on the rooting of cuttings of the rootstock IAC 766. For the prevalent colonization test, the fungus species detected and identified in 'Niagara Rosada' grafted on two rootstocks different were Phc and Phialemoniopsis ocularis. This is the first report of P. ocularis in a young vineyard in Brazil. Both fungi, in particular Phc, colonized only the plant's basal part, drawing attention to the rootstock as target for control measures. Measurement of the dark streaks in the vascular system revealed that Golia was the least susceptible rootstock, and IAC 572 was the most susceptible to Phc. Moreover, biofumigation or temperature of 37°C applied for 7 and 14 days, both followed by HWT, suppressed Phc in cuttings of the rootstock IAC 766 without hampering their rooting. Meanwhile, new studies are needed to validate the efficiency of these disinfection techniques.(AU)
A doença de Petri é complexa, ataca plantas jovens de videira e é difícil de ser controlada. O fungo Phaeomoniella chlamydospora é o principal agente causal dessa doença. Os objetivos deste estudo foram: avaliar o local prevalente dos fungos da doença de Petri, em diferentes partes de plantas de videira; avaliar a suscetibilidade de porta-enxertos de videira para o fungo P. chlamydospora; avaliar o efeito da solarização e da biofumigação seguido de tratamento com água quente sobre a desinfecção de estacas do porta-enxerto IAC 766 infectadas com o fungo P. chlamydospora; avaliar o efeito da solarização e da biofumigação seguido de tratamento com água quente sobre o enraizamento de estacas do porta-enxerto IAC 766. Para o teste de colonização, as espécies de fungos detectadas e identificadas em Niagara Rosada enxertada em dois porta-enxertos diferentes foram P. chlamydospora e Phialemoniopsis ocularis. Este é o primeiro relato de P. ocularis em parrerais jovens de videira no Brasil. Ambos os fungos, em particular P. chlamydospora, colonizaram somente a parte basal das plantas, destacando-se os porta-enxertos como foco para medidas de controle. Medidas das estrias escuras no sistema vascular revelaram que Golia foi o porta-enxerto menos suscetível, e o IAC 572 foi o mais suscetíveis para P. chlamydospora. Além disso, a biofumigação ou a temperatura de 37ºC aplicadas por 7 e 14 dias seguidas de tratamento com água quente eliminaram P. chlamydospora em estacas do porta-enxerto IAC 766 sem afetar o enraizamento. No entanto, novos estudos são necessários ainda para validar a eficiência dessas técnicas de desinfecção.(AU)
Assuntos
Vitis , Micoses , Desinfecção/métodos , PrevalênciaRESUMO
The occurrence of the black rat, Rattus rattus , in major Brazilian cities has increased in the recent years. To evaluate if the efforts of public rodent control have been reaching the species in the city of São Paulo, a survey was conducted in flooding areas using live trapping before and after implementation of the control program. Captures were carried out from 2009 to 2011, and animals were evaluated for their risk of zoonosis transmission. The number of R. rattus captured after control did not differ from the number of animals captured before the control program in the Spring/Summer season, but, in the Autumn/Winter season, effective control was observed. Low infestations of Ctenocephalides felis (Siphonaptera) and Echinolaelaps echidninus (Acarina) were observed, and antibodies against Leptospira spp. were detected in just 1 of 65 serum samples. Ten out of 18 serum samples were sororeactive for Vaccinia virus, suggesting contact between R. rattus and the pathogen Calodium hepaticum (= Capillaria hepaticum ) (Nematoda) was found in the liver of 73.4% of captured R. rattus. In conclusion, R. rattus may not be effectively controlled by the rodent Control Program in the city of São Paulo, and represents a threat to human health, justifying permanent environmental management and educational programs.(AU)
A ocorrência do rato de telhado, Rattus rattus , nas grandes cidades brasileiras aumentou nos últimos anos. A fim de investigar se os esforços do controle público de roedores têm atingido essa espécie, foi conduzido um levantamento em áreas com risco de inundação na cidade de São Paulo, com armadilhas para captura viva dos roedores, antes e depois do controle público. O estudo foi realizado entre 2009 e 2011, e os animais capturados foram estudados para identificar seu risco como transmissores de zoonoses. O número de R. rattus capturados após o controle não diferiu entre o número de animais capturados antes do programa de controle, no período de primavera/verão, mas, no período de outono/inverno, foi observada efetividade do controle. Foram registradas infestações baixas de Ctenocephalides felis (Siphonaptera) e Echinolaelaps echidninus (Acarina). Anticorpos contra Leptospira spp. foram detectados em apenas 1 das 65 amostras de soro. Dez entre 18 amostras de soro foram sororeativas para o vírus Vaccinia , sugerindo o contato entre R. rattus e o patógeno Calodium hepaticum (Nematoda) foi encontrado no fígado de 73,4% dos R. rattus capturados. Concluiu-se que R. rattus pode não ser controlado pelas ações propostas pelo Programa de Controle de Roedores na cidade de São Paulo e representa uma ameaça para a saúde humana, justificando permanentes programas de gestão ambiental e programas educacionais.(AU)
Assuntos
Animais , Ratos , Controle de Roedores , Sifonápteros , Ácaros e Carrapatos , Leptospira , ZoonosesRESUMO
Infectious bursal disease virus (IBDV) is classified according to the antigenicity and virulence into classical virulent (cv), very virulent (vv), and antigenic variant strains. The molecular basis for the IBDV antigenic variation is well established and is associated to the capsid protein, VP2 (gene VP2 of segment A), whereas both VP2 and the RNA-dependent RNA polymerase, VP1 (gene VP1 of segment B), have been correlated with the virulence. In this study, seventeen Brazilian IBDV samples previously characterized by the VP2 gene as cv (three) and vv (fourteen) strains were genetically and molecularly analyzed for their VP1 gene. All of the strains kept with the same cv or vv classification except one sample, Br/03/DR. This sample was classified as vv by its VP2 gene, but it was most closely related to the cv strains by its VP1 partial sequence and phylogeny. Studies on the phylogeny of VP1 have suggested a possible reassortment event that originated the vvVP1. In this case, the sample carrying vvVP2 and cvVP1 could be a descendant of IBDV ancestors prior to the reassortment of vvVP1; alternatively, it could be the result of a genetic exchange between the segments of different strains or with a live attenuated vaccine. Nevertheless, this is the first report of natural genetic reassortment of IBDV in Brazil.
Assuntos
Animais , Infecções por Birnaviridae , Variação Genética , Técnicas In Vitro , Filogenia , Reação em Cadeia da Polimerase , Recombinação Genética , Vírus da Doença Infecciosa da Bursa/genética , Vírus da Doença Infecciosa da Bursa/patogenicidade , Genótipo , Métodos , VirulênciaRESUMO
Eucalyptus ESTs libraries were screened for genes involved in lignin biosynthesis. This search was performed under the perspective of recent revisions on the monolignols biosynthetic pathway. Eucalyptus orthologues of all genes of the phenylpropanoid pathway leading to lignin biosynthesis reported in other plant species were identified. A library made with mRNAs extracted from wood was enriched for genes involved in lignin biosynthesis and allowed to infer the isoforms of each gene family that play a major role in wood lignin formation. Analysis of the wood library suggests that, besides the enzymes of the phenylpropanoids pathway, chitinases, laccases, and dirigent proteins are also important for lignification. Colocalization of several enzymes on the endoplasmic reticulum membrane, as predicted by amino acid sequence analysis, supports the existence of metabolic channeling in the phenylpropanoid pathway. This study establishes a framework for future investigations on gene expression level, protein expression and enzymatic assays, sequence polymorphisms, and genetic engineering
Assuntos
Etiquetas de Sequências Expressas , Eucalyptus/genética , Lignina/biossíntese , FenilpropionatosRESUMO
O objetivo do presente trabalho foi caracterizar geneticamente estirpes de Campylobacter jejuni subsp. jejuni isoladas de humanos e de diferentes origens animais (bovinas, suínas, cães, primatas, javalis, suínos e aves de corte). Um total de 828 amostras (fezes, carcaças, fetos abortados e útero histerectomizado) foram analisadas por métodos de rotina bacteriológica e 36 estirpes de C. jejuni foram isoladas. Trinta estirpes de origem fecal humana foram obtidas de laboratórios de análises clínicas da cidade de São Paulo. As 66 estirpes de C. jejuni isoladas foram submetidas à caracterização genética. Oligonucleotídeos baseados no gene fla A foram usados na reação de polimerase em cadeia (PCR) e amplificou um fragmento de 702 pb. Os produtos obtidos pela PCR foram avaliados pelas técnicas de seqüenciamento e análise genealógica. Análise da variabilidade genética das 66 estirpes revelou 44 diferentes subtipos de C. jejuni. Um subtipo de origem humana apresentou seqüência idêntica à de C. jejuni depositada no GenBank (GENBANK acesso número AF050186). A subtipagem das estirpes de C. jejuni baseadas no seqüenciamento da região variável do gene fla A e na análise do alinhamento das seqüências pelo método da Máxima Parcimônia, mostraram-se altamente discriminatórios fornecendo melhores condições para a correta diferenciação entre estirpes originárias de surto e as isoladas esporadicamente. Este foi o primeiro estudo de subtipagem molecular de estirpes de C. jejuni de origem humana e animal utilizando a técnica do seqüenciamento com análise genealógica realizado no Estado de São Paulo, Brasil.