Identificação de bactérias endossimbiontes associadas aos ácaros Tetranychus evansi e Tetranychus urticae (Acari: Tetranychidae) e seus efeitos na manipulação do mecanismo de defesa do tomateiro Lycopersicon esculentum Mill

• Autor(a) principal: Ribeiro, Fabricio Rainha
• Data de Publicação: 2011
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/3931
• topic: Ácaros; Defesa de planta; Bactérias; Tomate; Mites; Plant defense; Bacteria; Tomato; CNPQ::CIENCIAS BIOLOGICAS::PARASITOLOGIA::ENTOMOLOGIA E MALACOLOGIA DE PARASITOS E VETORES

The tomato is one of the most important vegetables produced in Brazil, playing an important role in the economy and creating jobs. In countries of South America, Europe and Africa, the mite Tetranychus evansi is considered an important pest of this crop. Recent studies have shown that this mite manipulates the defense of the plant reducing its defensive products. The objective of this study was to investigate whether endosymbiotic bacteria associated with the mite T. evansi play a role in manipulating the defenses of the tomato plant. The mite T. urticae was used as a standard, which is known to induce plant defense response. Bacterial DNA was extracted from T. evansi and T. urticae with subsequent denaturing gradient gel electrophoresis to compare bacterial diversity between these species, observing that T. evansi has a higher bacterial diversity than T. urticae. To determine if bacteria associated with T. evansi provide some advantage for its development and reproduction, as well as contributing to suppress the defenses of plants, mites were obtained without endosymbionts by treating them with a tetracycline solution. Mites treated with tetracycline showed no significant differences (p> 0.05) in development, oviposition and mortality. However, plants attacked by treated mites showed higher lipoxygenase activity and increased inhibition of trypsin (p <0.05) compared to clean plants and plants attacked by mites not treated with tetracycline. These results show that plants attacked by T. evansi without endosymbiotic bacteria activated their defense mechanism. Thus, these results suggest that bacteria may assist the mites in manipulating plant defense, making them more susceptible to attack.