Endossimbiose de Tetranychus evansi Baker e Pritchard (Acari: Tetranychidae) e a resposta de defesa induzida em tomateiro / Endosymbioses of Tetranychus evansi Baker and Pritchard (Acari: Tetranychidae) and tomato induced defence response

AUTOR(ES)
DATA DE PUBLICAÇÃO

2010

RESUMO

Interactions between arthropods and microorganisms have been receiving more attention due to the impact that these symbiotic associations causes on their macrosymbionts. Reproduction is the main biological parameters affected with cytoplasmic incompatibility and thelytokous parthenogenesis; however, endosymbionts can help arthropods to exploit host plants. In the feeding time, the herbivore causes injuries in plant tissue and induces a defense response in the plant that respond with production and posterior release of a variety of chemical compounds. However, in one case, plant defense system is affected and disturbed bay herbivore mite. It was detected in tomato plants when the mite Tetranychus evansi Baker and Pritchard interfered in the defense system of these plants, making them more nutritionally adequate for development of this mite. Continuing in the research line, the actual study locked for a better understanding of the interaction tomato and the mite T. evansi, in the possible symbiotic association presence between mite and microorganism that could promote advantages for this mite overcome the tomato defenses. Initially, molecular and microbiological analyses were performed to verify the presence of microorganisms. Later, mites were treated with the antibiotic tetracycline hydrochloride 0.2% that was the treated population. Control was represented from an untreated population and the possible advantage given by microorganism presence in the interior of the T. evansi organism was evaluated by the oviposition performance of the mite populations. Mite egg number was checked daily for four days. As substrate were used tomato leaves from Santa Clara I-5300 variety. In another experiment, chapter two, was evaluated the levels of proteinase inhibitors and total aldehydes that are present tomato damaged by treated and untreated mite population. As result from a first chapter, molecular analysis, using the method of polymerase chain reaction (PCR) confirmed the presence of bacterial DNA fragments in the untreated population and DNA fragments absence in the treated population. These results were confirmed by the microbiological analysis.Accessing the biological performance of treated and untreated was obtained that oviposition rate from treated population was 2.8 times lower than that of untreated population. In the second chapter was observed that the level of total aldehydes was low in plants damaged for treated and untreated treatments. These plants where put as feed and oviposition substrate for treated and untreated populations. Treated population put a same egg number on plants previously damaged by both populations. Already, untreated population showed highest oviposition rate on plants previously damaged by treated population. Thus, we can resume that the presence of microorganisms may be associated with nutritional benefits and detoxification. In determining the levels of proteinase inhibitors, treatment consists of plants infested with mites treated showed significantly lower value compared to other treatments. And the occurrence of microorganism and mite interaction can be related to potential of T. evansi to explore the nutritional quality and to confound the defense system of tomato plants. Future researches need be carried for to identify the microorganisms involved in the association and to study other possible effects of this interaction on other biological parameters of T. evansi.

ASSUNTO(S)

endossimbiose tetranychus evansi tomateiro entomologia agricola endosymbioses tetranychus evansi tomato

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