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Previous issue date: 2016-03-29 / Solanum lycopersicum L., tomato, is an herbaceous plant belonging to the Solanaceae family. Its fruits are consumed worldwide, reaching the world production of 160 million tons per year. In Brazil, it is the second vegetable in economic importance. However, the tomato is attacked by numerous diseases that lead to loss of production and /or poor quality of the fruit, such as the hollow stem, the disease caused by Pectobacterium spp. Due to the large number of diseases caused by plant pathogens, the tomato is a culture in which a significant amount of agrochemicals is used. Therefore, this species is among the vegetables with the greatest amount of residual pesticides. Under these circumstances, it is essential to develop sustainable plant defense techniques in order to reduce the use of agrochemicals. Then, changes in plant metabolism related to defense must be understood so that new strategies and new products can be developed. Disease control using soil microorganisms has been considered as an alternative, since the rhizobacteria, in addition to promoting plant growth, may induce resistance as the result of activation of the natural plant defenses. These, calls plant growth promoting rhizobacteria (PGPR), has been explored for their biofertilizers, biopesticides and phyto-stimulating abilities. The aims of this study were to characterize biochemically the Streptomyces spp. isolates, to determine the antagonism against Pectobacterium carotovorum subsp. brasiliensis (Pcb), to determine the ability of Streptomyces spp. on promoting growth of tomato plants and to evaluate the modulation of the defense-related metabolism of tomato plants when treated with Streptomyces spp. The possible influence of Streptomyces spp. on reducing soft rot disease in tomato plants was also evaluated. Biochemical characterization was evaluated through the ability of Streptomyces spp. on producing siderophores, solubilizing phosphate, and activity of amylase and lipase, as well as volatile organic compounds (VOC) production. Antagonism of Streptomyces spp. against Pcb was determined by dual-culture method and I-plate for VOC effect analysis. Plant growth promotion was evaluated through VOC emission and by direct interaction with Streptomyces spp. isolates (PM1, PM3, PM4, PM5, PM6 e PM9). Enzymes related to plant defense were colorimetric analyzed in plants treated with isolates of Streptomyces spp. Evaluation of soft rot disease was performed on plants treated with Streptomyces spp. and challenged with Pcb through the area under the disease progression curve (AUDPC) and plant mortality. Isolates of Streptomyces spp. displayed characteristics of PGPR and 32 volatile compounds were identified from the different isolates. PM3 was the isolate showing efficient antagonism against Pcb. Most of the isolates promoted increase of root and shoot length of tomato plants by VOC although PM5 was efficient on promoting growth by direct interaction with Streptomyces spp. Treatment with Streptomyces spp. modulated the activity of defense-related enzymes and decrease incidence of soft rot disease. / O tomateiro (Solanum lycopersicum L.) ? uma planta herb?cea pertencente ? fam?lia Solanaceae. Seus frutos s?o consumidos mundialmente, chegando ? produ??o mundial de 160 milh?es de toneladas por ano. No Brasil, ? a segunda hortali?a em import?ncia econ?mica. Contudo, o tomateiro ? alvo de in?meras doen?as que levam ? perda de produ??o e/ou m? qualidade dos frutos, como por exemplo, a doen?a Talo oco causada por Pectobacterium spp. Devido ao elevado n?mero de doen?as causadas por fitopat?genos, o tomateiro ? uma cultura onde se utiliza uma quantidade expressiva de agroqu?micos, estando entre as hortali?as que apresentam maior quantidade de agrot?xicos residuais. Por isso, torna-se imprescind?vel o desenvolvimento de t?cnicas sustent?veis de defesa para o vegetal, a fim de reduzir o uso destes compostos. Para este fim, ? fundamental compreender as altera??es no metabolismo vegetal relacionado ? defesa, para que novas estrat?gias e novos produtos agr?colas possam ser desenvolvidos. O controle de doen?as utilizando microrganismos de solo tem sido considerado uma alternativa, uma vez que as rizobact?rias, al?m de promoverem o crescimento vegetal, podem induzir ? resist?ncia como consequ?ncia da ativa??o da defesa vegetal. Estas, chamadas rizobact?rias promotoras de crescimento vegetal (PGPR), v?m sendo exploradas quanto ? capacidade biofertilizante, fito-estimuladora e biopesticida. Os objetivos deste estudo foram caracterizar seis isolados de Streptomyces spp. como PGPR, determinar o antagonismo contra Pectobacterium carotovorum subsp. brasiliensis (Pcb), determinar a capacidade de isolados de Streptomyces spp. na promo??o do crescimento de plantas de tomate e avaliar a modula??o do metabolismo relacionado ? defesa das plantas de tomate quando tratadas com Streptomyces spp. A poss?vel influ?ncia de Streptomyces spp. na redu??o da doen?a Talo oco em plantas de tomate tamb?m foi avaliada. A caracteriza??o bioqu?mica de isolados de Streptomyces spp. foi realizada por meio da capacidade de produzir sider?foros, solubilizar fosfato, e da atividade de amilase e lipase, bem como a produ??o de compostos org?nicos vol?teis. O antagonismo de Streptomyces spp. contra Pcb foi determinado pelo m?todo de dupla cultura e placa com barreira para an?lise do efeito de compostos org?nicos vol?teis (VOC). A promo??o do crescimento das plantas foi avaliada por meio de emiss?o de VOC e pela intera??o direta com os isolados de Streptomyces spp. (PM1, PM3, PM4, PM5, PM6 e PM9). Enzimas relacionadas ? resposta de defesa foram analisadas colorimetricamente em plantas tratadas com isolados de Streptomyces spp. A avalia??o da doen?a Talo oco foi realizada em plantas tratadas com Streptomyces spp. e desafiadas com Pcb atrav?s da ?rea sob a curva de progresso da doen?a e da mortalidade das plantas em 24 dias. Os isolados de Streptomyces spp. mostraram caracter?sticas de PGPR e 32 compostos vol?teis foram identificados como produtos dos diferentes isolados. PM3 foi o isolado mais eficiente quanto ao antagonismo contra Pcb. A maioria dos isolados promoveu o aumento do comprimento de raiz e da parte a?rea do tomateiro por VOC, embora PM5 tenha sido tamb?m eficiente na promo??o do crescimento atrav?s da intera??o direta com Streptomyces spp. O tratamento com Streptomyces spp. modulou a atividade de enzimas relacionadas ? defesa e diminuiu a incid?ncia da doen?a Talo oco.
| Identifer | oai:union.ndltd.org:IBICT/oai:tede2.pucrs.br:tede/7325 |
| Date | 29 March 2016 |
| Creators | Dias, Maila Pacheco |
| Contributors | Santar?m, Eliane Romanato |
| Publisher | Pontif?cia Universidade Cat?lica do Rio Grande do Sul, Programa de P?s-Gradua??o em Biologia Celular e Molecular, PUCRS, Brasil, Faculdade de Bioci?ncias |
| 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 PUC_RS, instname:Pontifícia Universidade Católica do Rio Grande do Sul, instacron:PUC_RS |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 8198246930096637360, 600, 600, 600, 36528317262667714, -1634559385931244697 |
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