Seleção e caracterização de novos genes vip3A: genes inseticidas de segunda geração de Bacillus thuringiensis
Arquivos
Data
2010-12-03
Autores
Marucci, Suzana Cristina [UNESP]
Título da Revista
ISSN da Revista
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Como uma alternativa para diminuir as agressões constantes que o ecossistema vem sofrendo, devido à grande quantidade de produtos químicos utilizados no controle de pragas, pesquisas envolvendo microrganismos capazes de promover o controle biológico tem se intensificado. Dentre estes microrganismos a bactéria Bacillus thuringiensis tem se destacado. Essa bactéria caracteriza-se pela produção de proteínas tóxicas a representantes de diversas ordens de insetos. Em particular, as proteínas Vip3A, estão em amplo estudo devido a sua especificidade, alto potencial ativo e como alternativa para o controle da resistência de insetos às proteínas Cry. Diante disto, o objetivo deste trabalho foi selecionar, a partir de 1080 isolados de diferentes regiões brasileiras, aqueles portadores de genes vip3A e obter a sequência de nucleotídeos completa dos mesmos. As linhagens padrão B. thuringiensis var. kurstaki HD1, B. thuringiensis var. tolworthi HD125 e o isolado I187 tiveram seus DNAs amplificados com oligonucleotídeos baseados na sequência de genes vip3A, descritos no banco de dados de B. thuringiensis e, a partir dos amplicons obtidos, a sequência completa de nucleotídeos dos mesmos foi determinada, utilizando-se da estratégia de “primer walking”. A proteína Vip3Aa43 (GenBank: [HQ594534]) da linhagem HD1 demonstrou ser 100% idêntica às proteínas Vip3Aa já descritas. Já as proteínas Vip3Aa42 (GenBank: [HQ587048]) da linhagem HD125 e Vip3Ag5 (GenBank: [HQ542193]) do isolado I187 demonstraram similaridade de 99% com as proteínas descritas Vip3Aa35 e Vip3Ag2, respectivamente, demonstrando serem duas novas proteínas Vip3A, devido às substituições de aminoácidos ocorridas. Os três genes vip3A obtidos poderão ser utilizados na produção de plantas Bt, piramidadas ou não, visando ao manejo da resistência dos insetos praga
As an alternative to decrease the constant aggressions that the ecosystem has suffered due to the large amount of chemical products used in pest control, researches involving microorganisms able to promoting biological control have been intensified. Among these microorganisms the bacterium Bacillus thuringiensis has been stood out. This bacterium is characterized by the production of toxic proteins to representatives of several insect orders. In particular, the Vip3A proteins are in large study due to its specificity, and high active potential as an alternative to control of insect's resistance to Cry proteins. According to this, the aim of this work was to select from 1080 isolates in different Brazilian regions, those carrying vip3A genes and obtain the complete nucleotide sequence of the same. The standard strains B. thuringiensis var. kurstaki HD1, B. thuringiensis var. tolworthi HD125 and the isolate I187 had their DNA amplified with primers based on vip3A gene sequence described in database of B. thuringiensis, and from the amplicons obtained, the full sequence of nucleotides was determined, by the use of the strategy of primer walking. The protein Vip3Aa43 (GenBank: [HQ594534]) of HD1 strain showed to be 100% identical to Vip3Aa proteins already described. However, the proteins Vip3Aa42 (GenBank: [HQ587048]) of HD125 strain and Vip3Ag5 (GenBank: [HQ542193]) of the isolate I187 showed 99% similarity with the Vip3Aa35 and Vip3Ag2 proteins described, respectively, showing been two new Vip3A proteins due to amino acid substitutions occurred. The three vip3A genes obtained can be used in the production of Bt crops, pyramidal or not, aiming to resistance management of pest insects
As an alternative to decrease the constant aggressions that the ecosystem has suffered due to the large amount of chemical products used in pest control, researches involving microorganisms able to promoting biological control have been intensified. Among these microorganisms the bacterium Bacillus thuringiensis has been stood out. This bacterium is characterized by the production of toxic proteins to representatives of several insect orders. In particular, the Vip3A proteins are in large study due to its specificity, and high active potential as an alternative to control of insect's resistance to Cry proteins. According to this, the aim of this work was to select from 1080 isolates in different Brazilian regions, those carrying vip3A genes and obtain the complete nucleotide sequence of the same. The standard strains B. thuringiensis var. kurstaki HD1, B. thuringiensis var. tolworthi HD125 and the isolate I187 had their DNA amplified with primers based on vip3A gene sequence described in database of B. thuringiensis, and from the amplicons obtained, the full sequence of nucleotides was determined, by the use of the strategy of primer walking. The protein Vip3Aa43 (GenBank: [HQ594534]) of HD1 strain showed to be 100% identical to Vip3Aa proteins already described. However, the proteins Vip3Aa42 (GenBank: [HQ587048]) of HD125 strain and Vip3Ag5 (GenBank: [HQ542193]) of the isolate I187 showed 99% similarity with the Vip3Aa35 and Vip3Ag2 proteins described, respectively, showing been two new Vip3A proteins due to amino acid substitutions occurred. The three vip3A genes obtained can be used in the production of Bt crops, pyramidal or not, aiming to resistance management of pest insects
Descrição
Palavras-chave
Entomopathogenic bacteria, Vegetative insecticidal protein, Primer walking, Biological control, Bacillus thuringiensis, Bactéria entomopatogênica, Proteínas inseticidas vegetativas, Primer walking
Como citar
MARUCCI, Suzana Cristina. Seleção e caracterização de novos genes vip3A: genes inseticidas de segunda geração de Bacillus thuringiensis. 2010. ix, 64 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias, 2010.