Fitopatologia - Artigos
URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11741
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Item Indutores de resistência no controle da pinta bacteriana do tomateiro e na atividade de enzimas de defesa(Tropical Plant Pathology, 2013-01) Resende, Renata S.; Rodrigues, Fabrício A.; Silveira, Patrícia R.; Rios, Jonas A.; Oliveira, José R.; Mariano, Rosa L. R.; Andrade, Camila C. L.Em três experimentos, avaliou-se o efeito de pulverizações de ácido jasmônico (AJ), etefon (ET) e acibenzolar-S-metil (Bion®) (ASM) a 0,1 mM, 0,5 mM e 0,3 g L-1, respectivamente, nos componentes de resistência do tomateiro (cv. Santa Clara) à pinta bacteriana, causada por Pseudomonas syringae pv. tomato e na atividade de peroxidases (POX), polifenoloxidases (PFO), β-1,3-glucanases (GLU) e lipoxigenases (LOX). Apenas no experimento 3, o período de incubação aumentou significativamente em um dia nas plantas pulverizadas com ASM, em comparação com as plantas pulverizadas com água (controle). O número de lesões por planta foi significativamente reduzido por AJ, ET e ASM nos três experimentos. Para algumas épocas de avaliação, a atividade de POX, PFO e GLU foram maiores para o AJ; de PFO, GLU e LOX, para o ASM; e de GLU e LOX, para o ET em comparação com o controle. Conclui-se que na presença de AJ, ET e ASM, os sintomas da pinta bacteriana foram reduzidos e a atividade das enzimas POX, PFO, GLU e LOX foram maiores.Item Volume de aplicação e eficiência do controle químico da mancha bacteriana em tomateiro industrial(Horticultura Brasileira, 2017-07) Maffia, Luiz A.; Pontes, Nadson C.; Nascimento, Abadia R.; Golynski, Adelmo; Moita, Antonio W.; Oliveira, José R.; Quezado-Duval, Alice M.Foi avaliado o efeito do volume de aplicação de hidróxido de cobre (HC) e do acibenzolar-S-metil (ASM) no controle da mancha bacteriana em tomate para processamento industrial. Os ensaios foram realizados em 2010, sendo um em Brasília-DF (ensaio 1), e dois em Morrinhos-GO (ensaios 2 e 3). Os volumes empregados foram 250 e 500 L/ha e as aplicações realizadas semanalmente, totalizando 13 aplicações. No terceiro ensaio, o número de aplicações do ASM foi reduzido para oito e as aplicações restantes foram feitas com HC. Após as duas primeiras aplicações, as plantas foram inoculadas artificialmente com Xanthomonas perforans (ensaios 1 e 2) e X. gardneri (ensaio 3). Foram avaliadas, de acordo com o ensaio, a severidade da doença, a produtividade e a relação benefício/custo para cada tratamento, tendo por base o incremento de produção em relação à testemunha não tratada. Em todos os ensaios, o volume de aplicação afetou a eficiência dos produtos, com maior redução da doença com aplicação de 500 L/ha. O efeito dos tratamentos na produtividade foi variável. Com base nos resultados do terceiro ensaio, com a aplicação de ASM-HC no volume de 250 L/ha, obteve-se a maior relação benefício/custo, seguido pelo tratamento com HC a 500 L/ha.Item Uso do algoritmo de Gower na determinação da divergência genética entre acessos de tomateiro do grupo cereja(Acta Scientiarum. Agronomy, 2010-07) Rocha, Mariella Camargo; Gonçalves, Leandro Simões Azeredo; Rodrigues, Rosana; Silva, Paula Renata Alves da; Carmo, Margarida Goréte Ferreira do; Abboud, Antonio Carlos de SouzaA análise conjunta de variáveis qualitativas e quantitativas tem sido apontada como ferramenta útil na estimativa da divergência genética entre os acessos de uma coleção de germoplasma. O presente trabalho teve como objetivos caracterizar uma coleção de germoplasma de tomateiro do grupo cereja, com base em descritores qualitativos e quantitativos e utilizar o algoritmo de Gower na quantificação da divergência genética. Estudaram-se 40 acessos de tomateiro cereja, cultivados em manejo orgânico nas condições de Seropédica, Estado do Rio de Janeiro. Foram utilizados quatro descritores qualitativos relacionados aos frutos e nove descritores quantitativos. Os dados foram analisados de forma conjunta pelo algoritmo de Gower. Detectou-se variabilidade para coloração, formato e número de lóculos do fruto. A coloração vermelha foi observada em 25 acessos testados, registrando-se também a produção de frutos amarelos, laranjas e marrons. Para número de lóculos, foi registrada a ocorrência de frutos bi, tri, tetra e pluriloculares (com até sete lóculos). O método UPGMA foi o que obteve o maior coeficiente de correlação cofenética (0,80), observando-se a formação de sete grupos. Os grupos formados permitiram a distinção de frutos classificados como cereja e outros que não se adequaram a esta definição, por estarem acima do diâmetro equatorial proposto para esta classe.Item Bactérias endofíticas como agentes promotores do crescimento de plantas de tomateiro e de inibição in vitro de Ralstonia solanacearum(Ciência e Agrotecnologia, 2008-05) Barretti, Patrícia Baston; Souza, Ricardo Magela de; Pozza, Edson AmpélioA partir de 150 isolados de bactérias endofíticas obtidos de folhas, caules e raízes de tomateiros sadios, 53 destacaram-se quanto à habilidade em promover o crescimento de plantas de tomateiro (Solanum lycopersicum L.). Submetidos a uma nova seleção, os isolados UFV-E17, UFV-E22, UFV-E25, UFV-E26, UFV-E27, Bacillus cereus (UFV-E29), UFV-E49, UFLA 06-LS, UFLA 08-LS e UFLA 11-LS apresentaram maior promoção do crescimento. Avaliações semanais de altura e número de folhas e folíolos das plantas aconteceram durante 45 dias. Após a sexta avaliação, mensurou-se a área foliar e o peso da matéria fresca e seca da parte aérea e da raiz das plantas. O isolado UFV-E49 apresentou melhor resultado para altura, área foliar, número de folhas e peso da matéria fresca e seca, tanto da parte aérea quanto da raiz. Dos isolados selecionados, somente dois apresentaram efeito inibitório direto in vitro a Ralstonia solanacearum.Item Biocontrol of gray mold in tomato plants by Clonostachys rosea(Tropical Plant Pathology, 2015-04) Borges, Álefe V.; Saraiva, Rodrigo M.; Maffia, Luiz A.Greenhouse conditions are favorable to the growth of Botrytis cinerea, and an increase in the occurrence of gray mold caused by this pathogen is therefore expected. Biocontrol using microbial antagonists is one of the approaches to control the pathogen. In previous experiments, Clonostachys rosea isolates suppressed B. cinerea in tomato leaves, but it was not evaluated in wounds caused during pruning, where the pathogen predominantly infects. Here, the efficacy of four C. rosea isolates to control B. cinerea in wounded tomato stems was evaluated. Influence of the following factors on the antagonist’s efficiency were evaluated: i) application time of C. rosea respectively to time for B. cinerea inoculum deposition, ii) conidial concentration of C. rosea, and iii) application of individual isolates versus isolate mixture. Results indicated that the four C. rosea isolates are effective in controlling gray mold, and that they may be applied either individually or as a mixture. The biocontrol efficiency of C. rosea was higher when it was applied 1 day before or simultaneously with the pathogen inoculation at a concentration of 106 conidia/mL- 1, reaching 100 % in stem segments and more than 90 % in whole plants. The antagonist has potential to be used in greenhouse tomato, especially in an integrated management context.Item Aggressiveness and host specificity of Brazilian isolates of Phytophthora infestans(Plant Pathology, 2004-08) Suassuna, N. D.; Maffia, L. A.; Mizubuti, E. S. G.The population of Phytophthora infestans in Brazil consists of two clonal lineages, US-1 associated with tomatoes and BR-1 associated with potatoes. To assess whether host specificity in these lineages resulted from differences in aggres- siveness to potato and tomato, six aggressiveness-related epidemiological components – infection frequency (IF), incu- bation period (IP), latent period (LP), lesion area (LA), lesion expansion rate (LER) and sporulation at several lesion ages (SSLA) – were measured on detached leaflets of late blight-susceptible potato and tomato plants. Infection frequency of US-1 was similar on potato and tomato leaflets, but IF of BR-1 was somewhat reduced on tomato. Incubation period was longer on both hosts with US-1, although this apparent lineage affect was not significant. Overall there was no host effect on IP. On potato, BR-1 had a shorter LP (110·3 h) and a larger LA (6·5 cm 2 ) than US-1 (LP = 162·0 h; LA = 2·8 cm 2 ). The highest LER resulted when isolates of BR-1 (0·121 cm 2 h −1 ) and US-1 (0·053 cm 2 h −1 ) were inoculated on potato and tomato leaflets, respectively. The highest values of the area under the sporulation capacity curve (AUSC) were obtained for isolates of US-1 inoculated on tomato leaflets (6146) and for isolates of BR-1 on potato leaflets (3775). In general, higher values of LA, LER, SSLA and AUSC, and shorter values of LP were measured when isolates of a clonal lineage were inoculated on their original host than with the opposite combinations. There is evidence that there are quan- titative differences in aggressiveness components between isolates of US-1 and BR-1 clonal lineages that probably con- tribute to host specificity of P. infestans populations in Brazil.Item Phoma destructiva causing blight of tomato plants: a new fungal threat for tomato plantations in Brazil?(Tropical Plant Pathology, 2017-11-20) Colmán, Adans A.; Alves, Janaina L.; Silva, Meiriele da; Barreto, Robert W.Solanum lycopersicum is among the most important crops in Brazil. This crop is affected by a large range of fungal diseases that are recognized as major limitations for tomato production. Recently, plants grown in a greenhouse in Viçosa, Minas Gerais, Brazil, were found to bear severe blight symptoms. A pycnidial coelomycete was repeatedly found in association with necrotic tissues. The fungus had its morphology recognized as equivalent to that of Phoma and related genera. A phylogenetic analysis based on nrDNA (ITS) and partial β-tubulin (TUB) sequences led to the conclusion that the fungus involved was Phoma destructiva. Pathogenicity tests showed that, after 5 days, blight symptoms developed on leaves, flowers and stems of plants belonging to thirteen different tomato varieties tested. This fungal species is mostly known for causing post-harvest tomato rot, which is only regarded as a secondary disease in Brazil. This is in disagreement with the observations made in this work. Here, the disease symptoms caused by the fungus were very severe, fully justifying the scientific name of the pathogen. Under favorable environmental conditions, aggressive strains of P. destructiva, such as the one isolated in this study, may become significant threats to tomato plantations in Brazil.Item Nematode root herbivory in tomato increases leaf defenses and reduces leaf miner oviposition and performance(Journal of Chemical Ecology, 2017-01-13) Arce, Carla C. M.; Machado, Ricardo A. R.; Ribas, Natália S.; Cristaldo, Paulo F.; Ataíde, Lívia M. S.; Pallini, Ângelo; Carmo, Flávia M.; Freitas, Leandro G.; Lima, EraldoThe outcome of plant-mediated interactions among herbivores from several feeding guilds has been studied intensively. However, our understanding on the effects of nematode root herbivory on leaf miner oviposition behavior and performance remain limited. In this study, we evaluated whether Meloidogyne incognita root herbivory affects Tuta absoluta oviposition preference on Solanum lycopersicum plants and the development of the resulting offspring. To investigate the M. incognita-herbivory induced plant systemic responses that might explain the observed biological effects, we measured photosynthetic rates, leaf trypsin protease inhibitor activities, and analyzed the profile of volatiles emitted by the leaves of root-infested and non-infested plants. We found that T. absoluta females avoided laying eggs on the leaves of root-infested plants, and that root infestation negatively affected the pupation process of T. absoluta. These effects were accompanied by a strong suppression of leaf volatile emissions, a decrease in photosynthetic rates, and an increase in the activity of leaf trypsin protease inhibitors. Our study reveals that root attack by nematodes can shape leaf physiology, and thereby increases plant resistance.Item Key factors to inoculate Botrytis cinerea in tomato plants(Summa Phytopathologica, 2014-07-28) Borges, Álefe Vitorino; Saraiva, Rodrigo Moreira; Maffia, Luiz AntonioStudies addressing the biological control of Botrytis cinerea have been unsuccessful because of fails in inoculating tomato plants with the pathogen. With the aim of establishing a methodology for inoculation into stems, experiments were designed to assess: i. the aggressiveness of pathogen isolates; ii. the age at which tomato plants should be inoculated; iii. the susceptibility of tissues at different stem heights; iv. the need for a moist chamber after inoculation; and v. the effectiveness of gelatin regarding inoculum adhesion. Infection with an isolate from tomato plants that was previously inoculated into petioles and then re-isolated was successful. An isolate from strawberry plants was also aggressive, although less than that from tomato plants. Tomato plants close to flowering, at 65 days after sowing, and younger, middle and apical stem portions were more susceptible. There was positive correlation between lesion length and sporulation and between lesion length and broken stems. Lesion length and the percentage of sporulation sites were reduced by using a moist chamber and were not affected by adding gelatin to the inoculum suspension. This methodology has been adopted in studies of B. cinerea in tomato plants showing reproducible results. The obtained results may assist researchers who study the gray mold.Item Rhizobacteria induces resistance against Fusarium wilt of tomato by increasing the activity of defense enzymes(Bragantia, 2014-07-02) Ferraz, Hélvio Gledson Maciel; Resende, Renata Sousa; Silveira, Patrícia Ricardino; Andrade, Camila Cristina Lage; Milagres, Elisângela Aparecida; Oliveira, José Rogério; Rodrigues, Fabrício de ÁvilaFusarium wilt, caused by Fusarium oxysporum f.sp. lycopersici (Fol), is one of the most important diseases that affect tomato yield worldwide. This study investigated the potential of three antagonists, Streptomyces setonii (UFV 618), Bacillus cereus (UFV 592) and Serratia marcescens (UFV 252), and as positive control the hormone jasmonic acid (JA), to reduce Fusarium wilt symptoms and to potentiate the defense enzymes in the stem tissues of tomato plants infected by Fol. The seeds were microbiolized with each antagonist, and the soil was also drenched with them. The plants were sprayed with JA 48 h before Fol inoculation. The area under the Fusarium wilt index progress curve was reduced by 54, 48, 47 and 45% for the UFV 618, JA, UFV 592 and UFV 252 treatments, respectively. The three antagonists, and even the JA spray, efficiently reduced the Fusarium wilt symptoms on the tomato plant stems, which can be explained by the lower malondialdehyde concentration (an indication of oxidative damage to lipids in the plasma membranes) and the greater activities of peroxidases, polyphenoloxidases, glucanases, chitinases, phenylalanine ammonia-lyases and lipoxygenases, which are commonly involved in host resistance against fungal diseases. These results present a novel alternative that can be used in the integrated management of Fusarium wilt on tomatoes.