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Previous issue date: 2015-12-15 / Cotton is an economically important natural fiber produced in the world and it is highly affected
by insect pests and pathogens. Several transgenic approaches have been developed to improve
cotton???s resistance through the expression of different transgenes, including Cry toxins,
hydrolytic proteinase inhibitors, toxic peptides, dsRNA, among others. However,
transformation methods remain limited by cotton variety due to the difficulties imposed by
tissue culture and the steps necessary in Agrobacterium-mediated transformation and/or particle
bombardment. The pollen tube transformation technique involves the introduction of an
exogenous DNA into the plant genome being independent of tissue culture. This method can
be applied into different cotton cultivars and it has been used successfully in generation of Bt
cotton. In Chapter 2, the pollen-tube pathway technique was used to transform a Brazilian
cotton cultivar. The putative transgenic plants derived from boll seeds injected with a binary
expression vector, harboring the cry1Ia12 gene were initially selected with kanamycin. Selected
plants were characterized using PCR, Southern blot, Western blot and ELISA techniques to
confirm the genetic transformation. Western blot and ELISA data showed variable protein
expression among the transgenic plants varying from 1,?? ??g g-1 to ??,??6 ??g g-1. An insect
bioassay using T1 plants revealed the entomotoxic effects of Cry1Ia12 on Spodoptera
frugiperda, as evidenced by a decrease in the development of insects compared with
untransformed controls. Entomotoxic effect with Anthonomus grandis was also demonstrated
by a decrease in the number of emerging insect adults. In Chapter 3, the agrolistic
transformation technique was used to transform the Coker 310 cultivar. The putative transgenic
plants derived from transformed embryos with a vector harboring the cry8Ka5 and ??AI-C3
genes were selected in vitro, and acclimatized in a greenhouse. Acclimatized plants were
characterized using PCR and ELISA techniques to confirm the genetic transformation.
Collected seeds from positive plants were sown for T1 plants analysis, aiming the technique
evaluation. It was observed the cry8Ka5 gene amplification, and the ELISA results showed
variable protein expression between transgenic plants. It was possible to demonstrate with this
work, the efficacy of GM cotton plants generation using alternative biotechnological
approaches, efficiently applied to the lepidopterans and coleopterans control. / O algod??o ?? uma fonte de fibra natural de grande import??ncia econ??mica, sendo uma cultura
altamente afetada por diferentes insetos-praga e pat??genos. Diversas estrat??gias de transgenia
t??m sido desenvolvidas para melhorar a resist??ncia do algod??o, por meio da express??o de
transgenes, incluindo toxinas Cry, inibidores de enzimas hidrol??ticas, pept??deos t??xicos,
dsRNA, entre outros. No entanto, os m??todos de transforma????o ainda s??o limitados a algumas
variedades de algod??o devido ??s dificuldades impostas pela cultura de tecidos e ??s etapas
necess??rias de transforma????o, seja mediada por Agrobacterium e/ou bombardeamento de
part??culas. A t??cnica de transforma????o via tubo pol??nico ?? uma t??cnica que envolve a introdu????o
de DNA gen??mico ex??geno em plantas, sendo independente de cultura de tecidos. Este m??todo
pode ser aplicado para diferentes cultivares de algod??o e tem sido utilizado com sucesso na
gera????o de algod??o Bt. No Cap??tulo 2, a t??cnica de transforma????o via tubo pol??nico foi utilizada
para transformar uma cultivar de algod??o brasileira. As potenciais plantas transg??nicas geradas,
derivadas de sementes que tiveram o bot??o floral injetado com um vetor de express??o bin??rio,
portador do gene cry1Ia12, foram inicialmente selecionadas com o antibi??tico canamicina.
Plantas selecionadas foram caracterizadas por PCR, Southern blot, Western blot, e ensaio de
ELISA, visando confirmar a transforma????o gen??tica. Os dados de Western blot e de ELISA
mostraram uma express??o vari??vel da prote??na entre as plantas transg??nicas, com concentra????es
variando de 1,?? ??g g-1 a ??,??6 ??g g-1. Ensaios biol??gicos com o inseto alvo utilizando plantas T1
revelaram os efeitos entomot??xicos da toxina Cry1Ia12 em Spodoptera frugiperda, evidenciado
por uma diminui????o no desenvolvimento de insetos, em compara????o com as plantas controle
n??o transformadas. Foi observado um efeito entomot??xico em Anthonomus grandis,
demonstrado pela diminui????o no n??mero de adultos emergentes. No Cap??tulo 3, a t??cnica de
transforma????o via agrol??stica foi utilizada para transformar uma cultivar de algod??o Coker 310
visando avaliar essa t??cnica. As plantas potencialmente transg??nicas geradas, derivadas dos
embri??es transformados com o vetor portando os genes cry8Ka5 e ??AI-C3 foram selecionados
in vitro e, posteriormente, aclimatizados em casa de vegeta????o. Estas plantas foram
caracterizadas por PCR e ELISA para confirmar a transforma????o gen??tica. Sementes das
plantas positivas foram semeadas para an??lise das plantas T1. A amplifica????o do gene cry8Ka5
foi observada e os resultados de ELISA mostraram uma express??o vari??vel da prote??na entre as
plantas transg??nicas. Os estudos aqui apresentados demonstraram a efici??ncia na gera????o de
plantas de algod??o GM, utilizando abordagens biotecnol??gicas alternativas e eficientes para
controle de lepid??pteros e cole??pteros.
| Identifer | oai:union.ndltd.org:IBICT/oai:bdtd.ucb.br:tede/2083 |
| Date | 15 December 2015 |
| Creators | Oliveira, Raquel Sampaio de |
| Contributors | S??, Maria F??tima Grossi de |
| Publisher | Universidade Cat??lica de Bras??lia, Programa Strictu Sensu em Ci??ncias Gen??micas e Biotecnologia, UCB, Brasil, Escola de Sa??de e Medicina |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da UCB, instname:Universidade Católica de Brasília, instacron:UCB |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | -2827197273900952156, 500, 500, 600, -6392058866414562720, -5518144268585252051 |
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