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Previous issue date: 2015-09-09 / CAPES / The fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici is a disease of economic importance to tomato crop (Lycopersicon esculentum Mill.) because of the losses caused in the production. This study aimed to select bacteria belonging to the genus Bacillus which have antagonistic activity to fungi present in tomato producing areas. It was obtained 193 bacterial isolates from tomato roots and stems. We performed the complete sequencing 16S rRNA subunit of 32 bacteria from the work collection using the 27F and Amp2 primers. These bacteria were randomly selected, and 20 bacteria were obtained from healthy tomato plants. The results showed a high similarity to species of the genus Bacillus: B. thuringiensis, B. megaterium, B. cereus, B. toyonensis, B. stratosphericus and Paenibacillus barcinonensis. Evaluation of the functional characteristics of the bacterial strains showed that 72% possess proteolytic activity, 78% have cellulolytic activity, 48% are able to solubilize inorganic phosphate, 42% solubilize zinc oxide and 40.8% are able to produce indols. Antagonism tests carried out in vitro showed that some bacterial strains reduced the mycelial growth of the three races of the fungus when subjected to direct method (parallel streaks). An experiment was conducted using the genotypes Debora Plus, Santa Clara Miss Brazil, Perinha and Carolina in order to select a sensitive tomato genotype to the three fungal races. The Perinha variety was the most susceptible for races 1, 2 and 3 and presented the highest percentage of fungal colonization. Thus, this variety was used in a greenhouse experiments to evaluate the antagonistic role of the Bacillus strains against three fungal races. The antagonistic activity of bacteria was assessed 15 days after transplanting of the tomato seedlings to contaminated substrate. The results showed that the B. stratosphericus strain contributed to control at least 93.25% of the damage caused by race 1, strains from species B. megaterium and B. thuringiensis controlled 100% the damage caused by race 2 and at least 67.35% of the disease caused by the race 3 of the fungus. The results suggest that some strains have the potential to control race 1, 2 and 3 of the F. oxysporum f. sp. lycopersici and have functional activities that may contribute to improving the growth of tomato plants. However, field studies are needed to confirm the role of these Bacillus species during the interaction with tomato plants grown in soil contaminated with the race 1, 2 and 3 of the fusarium wilt. / A murcha-de-fus?rio causada por Fusarium oxysporum f. sp. lycopersici ? uma doen?a de grande import?ncia econ?mica para a cultura do tomateiro (Lycopersicon esculentum Mill.) devido as perdas que ocasiona na produ??o. O presente estudo teve como objetivo selecionar bact?rias pertencentes ao g?nero Bacillus que apresentam atividade antag?nica para aplica??o em ?reas produtoras de tomate infestadas pelo fungo. Foram obtidos 193 isolados de bact?rias de ra?zes e hastes de tomateiro. Foi realizado o sequenciamento completo da subunidade 16S RNAr de 32 isolados da cole??o de trabalho, utilizando os iniciadores 27F e Amp2. Essas bact?rias foram selecionadas aleatoriamente, sendo que 20 bact?rias foram obtidas de tomateiro sadio. Os resultados mostraram uma alta similaridade das estirpes com as esp?cies do g?nero Bacillus: B. thuringiensis, B. megaterium, B. cereus, B. toyonensis, B. stratosphericus, al?m da esp?cie Paenibacillus barcinonensis. Testes para avaliar as caracter?sticas funcionais das estirpes bacterianas in vitro mostraram que 72% das estirpes possuem atividade proteol?tica, 78% possuem atividade celulol?tica, 48% solubilizam fosfato inorg?nico, 42% solubilizam zinco e 40,8% s?o capazes de produzir indol. Testes de antagonismo realizados in vitro mostraram que algumas estirpes bacterianas retardaram ou reduziram o crescimento micelial das tr?s ra?as do fungo quando submetidos ao m?todo de a??o direta (estrias paralelas). Com o objetivo de selecionar um gen?tipo de tomateiro sens?vel as tr?s ra?as do fungo, foi instalado um experimento utilizando os gen?tipos D?bora Plus, Santa Clara Miss Brasil, Perinha e Carolina. A variedade Perinha foi a mais suscet?vel as ra?as 1, 2 e 3 j? que apresentou um maior percentual de coloniza??o do fungo. A atividade antag?nica das bact?rias foi avaliada 15 dias ap?s o transplantio das mudas de tomate da variedade Perinha para o substrato contaminado. Os resultados mostraram que a estirpe da esp?cie B. stratosphericus controlou cerca de 93,25% das plantas crescidas na presen?a da ra?a 1 do fungo. J? as esp?cies B. megaterium e B. thuringiensis controlaram 100% da doen?a das plantas de tomateiro cultivadas em substrato com a ra?a 2 e de 67,35% das plantas cultivadas em substrato com a ra?a 3 do fungo. Os resultados obtidos sugerem que algumas estirpes possuem potencial para controle de F. oxysporum f. sp. lycopersici ra?a 1, 2 e 3 e possuem atividades funcionais que podem contribuir para a melhoria do crescimento das plantas de tomateiro cultivadas em ?reas infestadas com o fungo. Entretanto, estudos em campo s?o necess?rios para confirmar o papel dessas esp?cies de Bacillus na intera??o com plantas de tomateiro cultivadas na presen?a das ra?as 1, 2 e 3 da murcha de fus?rio.
| Identifer | oai:union.ndltd.org:IBICT/oai:localhost:jspui/1851 |
| Date | 09 September 2015 |
| Creators | ROCHA, Francine Yuriko Otsuka |
| Contributors | Baldani, Jos? Ivo, Carmo, Margarida Gor?te Ferreira do, Baldani, Jos? Ivo, Olivares, F?bio Lopes, Ara?jo, Jo?o Sebasti?o de Paula |
| Publisher | Universidade Federal Rural do Rio de Janeiro, Programa de P?s-Gradua??o em Fitotecnia, UFRRJ, Brasil, Instituto de Agronomia |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da UFRRJ, instname:Universidade Federal Rural do Rio de Janeiro, instacron:UFRRJ |
| Rights | info:eu-repo/semantics/openAccess |
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