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Previous issue date: 2017-08-25 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Tomato (Solanum lycopersicum) cultures are frequently attacked by many pathogens,
leading to yield losses. Among the pathogens, the fungus Alternaria solani (?Early blight?
disease) can cause significant yield reductions and decreases the fruit quality. Due to the
high susceptibility of tomato to fungal pathogens, the agricultural practices include the
intensive use of agrochemicals, which may result in fruits with high levels of residual
pesticides and higher production costs. The promotion of plant defense system represents
an additional tool for disease control and plant growth management. Some rhizobacteria
have been shown the ability to affect plant development and modulate plant defense
against pathogens. Among those bacteria, the genus Streptomyces is able to synthesize
molecules that directly interfere with growth, through auxin and ACC deaminase
production, and indirectly, through antibiotics and siderophores synthesis. The aim of this
work was to select Streptomyces (CLV04, CLV05 and CLV07) with the ability to promote
seed germination and plant growth, as well as improve tomato plant resistance against A.
solani. Results showed that CLV07 delayed the initial seed germination, but it did not
impair the final germination process. However, CLV04, CLV05 and CLV07 reduced the
early root and shoot growth. All these rhizobacteria produced high auxin levels. CLV07
was efficient for inducing plant resistance against A. solani. Furthermore, all CLVs showed
antagonism by competition, decreasing the A. solani growth. Taking together all results,
Streptomyces tested were deleterious for seed and initial plant growth, but CLV07 showed
a potential to be used for inducing plant resistance. However, the inoculation of these
rhizobacteria on seeds is not recommended. / O tomateiro (Solanum lycopersicum) ? constantemente atacado por diversos pat?genos,
levando a perdas de produtividade. Dentre os principais pat?genos, destaca-se o fungo
Alternaria solani que causa a doen?a ?pinta-preta? (?Early blight?), capaz de reduzir a
produ??o e/ou levar ? forma??o de frutos de baixa qualidade. Devido ? grande
susceptibilidade do tomateiro a pat?genos, as pr?ticas agr?colas incluem o uso intensivo de
agroqu?micos que resultam, frequentemente, em tomates com altos n?veis residuais de
pesticidas. A promo??o do crescimento e da defesa vegetal utilizando microrganismos
representa uma ferramenta para o manejo do tomateiro. Dentre as diversas rizobact?rias
com capacidade de modular o crescimento e a defesa vegetal, o g?nero Streptomyces vem
se destacando. Estas bact?rias s?o capazes de sintetizar mol?culas que interferem tanto
diretamente no crescimento, como a auxina e a ACC desaminase, quanto indiretamente,
atrav?s da produ??o de antibi?ticos e sider?foros. Pretendeu-se, neste trabalho, selecionar
isolados de Streptomyces (CLV04, CLV05 e CLV07) com capacidade de promover a
germina??o e o crescimento de plantas de tomate, al?m de aumentar a resist?ncia vegetal
contra A. solani. Os resultados demonstram que o CLV07 causou retardo na germina??o,
mas n?o reduziu a taxa final de germina??o. Apesar das rizobact?rias CLV04, CLV05 e
CLV07 produzirem elevados n?veis de auxina, elas causaram a redu??o do crescimento
tanto da raiz quanto da parte a?rea de pl?ntulas de tomate cultivadas in vitro. O CLV07 foi
eficiente na promo??o da defesa de plantas de tomate contra A. solani. Todas as
rizobact?rias apresentaram antagonismo por competi??o, reduzindo o crescimento do
mic?lio do fungo A. solani. Considerando todos os resultados, as diferentes bact?rias
Streptomyces foram prejudiciais ? germina??o e ao crescimento inicial de pl?ntulas de
tomate. Desta forma, n?o ? recomend?vel a utiliza??o destas bact?rias em sementes e
pl?ntulas jovens. Contudo, o CLV07 apresenta potencial para ser utilizado para a indu??o
de resist?ncia de plantas de tomate contra o pat?geno A. solani.
| Identifer | oai:union.ndltd.org:IBICT/oai:tede2.pucrs.br:tede/7872 |
| Date | 25 August 2017 |
| Creators | Leite, Andressa Von Wurmb Helrighel |
| Contributors | Astarita, Leandro Vieira, Silva, Renata Medina da |
| Publisher | Pontif?cia Universidade Cat?lica do Rio Grande do Sul, Programa de P?s-Gradua??o em Biologia Celular e Molecular, PUCRS, Brasil, Escola de Ci?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, 500, 500, 600, -1634559385931244697, 2075167498588264571 |
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