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Desenvolvimento de agentes de controlo biológico para o controlo da gafa (Colletotrichum spp.) e tuberculose (Pseudomonas savastanoi pv. savastanoi) da oliveira
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Abstract(s)
Este estudo teve como objetivo construir uma biblioteca de bactérias endófitas de
plantas arbóreas para a sua triagem contra patógenos vegetais com especial foco nas
duas principais doenças da oliveira, a gafa (Colletotrichum spp.) e a tuberculose
(Pseudomonas savastanoi pv. savastanoi). Para o efeito foi pedido a alunos do secundário
e do ensino superior que recolhessem ramos de árvores na região de Elvas, Portugal.
A recolha resultou em mais de 30 amostras oriundas de mais de 10 espécies de
plantas. As amostras permitiram isolar 190 bactérias morfologicamente diferentes que,
no futuro, serão sujeitas a ensaios de inibição de diferentes patógenos vegetais. Com o
intuito de garantir o sucesso desses ensaios futuros, foram estabelecidos e otimizados
protocolos de inibição de crescimento em meio sólido de Colletotrichum spp. e P.
savastanoi pv. savastanoi com uma biblioteca de bactérias endófitas de algas marinhas.
Os métodos mostraram-se adequados e identificaram-se bactérias que inibem,
simultaneamente, os agentes causais das duas doenças mais importantes da oliveira.
Numa tentativa de melhorar a triagem dos microrganismos através de ensaios de
inibição em folha, foram realizados ensaios de patogenicidade de Colletotrichum spp. em
folhas destacadas de oliveira e a severidade da doença foi quantificada
automaticamente por um macro. Usaram-se folhas recolhidas no repouso invernal de
duas variedades, Arbequina e Galega Vulgar por serem moderadamente e muito
suscetíveis à gafa, respetivamente. Os resultados sugerem que a variedade Galega não
é muito afetada pelo fungo e a variedade Arbequina foi a que teve maior grau de
severidade de sintomas. O ensaio foi repetido com folhas em diferentes estados
fenológicos e os resultados sugerem que o agente causal da gafa tem maior capacidade
de causar sintomas em folhas colhidas durante o repouso vegetativo.
This study aimed to build a library of endophytic bacteria from trees to screen it against plant pathogens with a special focus on the main diseases of olive, anthracnose (Colletotrichum spp.) and olive knot (Pseudomonas savastanoi pv. savastanoi). For this purpose, high school and university students were asked to collect tree branches in Elvas Region, Portugal. The collection resulted in more than 30 samples from more than 10 plant species. The samples allowed the isolation of 190 morphologically different bacteria that in the future will be subjected to inhibition tests of different plant pathogens. In order to ensure the success of these future trials, protocols for growth inhibition on solid medium of Colletotrichum spp. and P. savastanoi pv. savastanoi were established and optimized with a library of endophytic bacteria from marine algae. The methods proved adequate, and bacteria were identified that simultaneously inhibit the causal agents of the two most important diseases of olive. To improve the screening of microorganisms by leaf inhibition assays, pathogenicity assays of Colletotrichum spp. were performed on detached olive leaves and disease severity was quantified automatically by a macro. Leaves collected at winter rest of two varieties, Arbequina and Galega Vulgar were used as they are moderately and highly susceptible to olive anthracnose, respectively. The results suggest that the Galega variety is not very affected by the fungus and the Arbequina variety had the highest degree of severity of symptoms. The trial was repeated with leaves at different phenological stages, and the results showed that the causal agent of olive anthracnose has a greater capacity to cause symptoms on leaves harvested during vegetative rest.
This study aimed to build a library of endophytic bacteria from trees to screen it against plant pathogens with a special focus on the main diseases of olive, anthracnose (Colletotrichum spp.) and olive knot (Pseudomonas savastanoi pv. savastanoi). For this purpose, high school and university students were asked to collect tree branches in Elvas Region, Portugal. The collection resulted in more than 30 samples from more than 10 plant species. The samples allowed the isolation of 190 morphologically different bacteria that in the future will be subjected to inhibition tests of different plant pathogens. In order to ensure the success of these future trials, protocols for growth inhibition on solid medium of Colletotrichum spp. and P. savastanoi pv. savastanoi were established and optimized with a library of endophytic bacteria from marine algae. The methods proved adequate, and bacteria were identified that simultaneously inhibit the causal agents of the two most important diseases of olive. To improve the screening of microorganisms by leaf inhibition assays, pathogenicity assays of Colletotrichum spp. were performed on detached olive leaves and disease severity was quantified automatically by a macro. Leaves collected at winter rest of two varieties, Arbequina and Galega Vulgar were used as they are moderately and highly susceptible to olive anthracnose, respectively. The results suggest that the Galega variety is not very affected by the fungus and the Arbequina variety had the highest degree of severity of symptoms. The trial was repeated with leaves at different phenological stages, and the results showed that the causal agent of olive anthracnose has a greater capacity to cause symptoms on leaves harvested during vegetative rest.
Description
Keywords
: Colletotrichum spp Pseudomonas savastanoi Antracnose da oliveira Tuberculose da oliveira Agentes de Controlo Biológico
Citation
Canha, H.A.(2023).Desenvolvimento de agentes de controlo biológico para o controlo da gafa (Colletotrichum spp.) e tuberculose (Pseudomonas savastanoi pv. savastanoi) da oliveira. Escola Superior Agrária de Elvas, 2023
Publisher
Escola Superior Agrária de Elvas