Título:	Promoção de crescimento e controle de insetos das ordens Lepidoptera e Hemiptea via colonização sistêmica por Bacillus thuringiensis em algodoeiro e tomateiro
Autor(es):	Costa, Flávia Santana Souza da
Orientador(es):	Pontes, Rose Gomes Monnerat Solon de
Assunto:	Bacillus thuringiensis Biocontrole Algodão - doenças e pragas Plantas - desenvolvimento
Data de publicação:	6-Ago-2024
Data de defesa:	16-Out-2023
Referência:	COSTA, Flávia Santana Souza da. Promoção de crescimento e controle de insetos das ordens Lepidoptera e Hemiptea via colonização sistêmica por Bacillus thuringiensis em algodoeiro e tomateiro. 2023. 211 f., il. Tese (Doutorado em Agronomia) — Universidade de Brasília, Brasília, 2023.
Abstract:	Bacillus thuringiensis (Bt) toxins have been used as bioinsecticides in the control of insect’s orders Coleoptera, Lepidoptera and Diptera, and some toxins were selected for mites, nematodes and in sucking insects of the order Hemiptera. The Bt demonstrated the ability to induce growth of cotton plants, furthermore, to have toxic effect against Spodoptera frugiperda. The discovery of this endophytic ability of Bt opened prospects for further studies using this bioinsecticide against chewing and sucking insects, as well as in other plants species. Thus, the objective of this study was: (a) to evaluate the growth of cotton plants according to the method of inoculation by Bt and to evaluate the germination potential of cotton cultivars submitted to seed treatment with the bacterium; (b) to evaluate the development of S. frugiperda fed in their larval phase with cotton plants endophytically colonized with Bt and to verify the oviposition behavior; (c) test the ability of Bemisia tabaci to acquire Bt and test the oviposition preference in inoculated and non-inoculated plants with Bt; (d) to evaluate the effects of tomato colonization by Bt strains on the growth promoter capacity and its toxicity on Helicoverpa armigera. Plant trials showed that Bt treatment positively affected the rate of emergence speed and the development of cotton plants with an increase of about 30% in the dry weight of the roots of the cultivar IMA 1318 and 14% in the weight of the roots of the cultivar BRS 8H. About 40% of the tested genotypes were positively affected by the use of Bt in the treatment of the seeds and the dry matter of the plants of the cultivar IMA 6035 B2RF increased around 30%. As for the bioassays with the pest insects, it was observed that the treatments with Bt did not negatively influence the duration and viability of S. frugiperda. After the 72 hour period, the plants of the control treatment had a higher number of ovipositions than the plants treated with the bacterium. In the assay of Bt translocation and acquisition by B. tabaci, the Bt endophytic colonization in cotton plants with the ability to be acquired by B. tabaci adults and nymphs during feeding was confirmed. Furthermore, plants that were treated with strain S1806 presented lower numbers of B. tabaci eggs. The tomato colonized with Bt showed no differences for the growth of the plants. The colonization and translocation by Bt in tomato plants were confirmed by visualization of their structures by microscopy and by Bt recovery of roots, stem and leaves of plants treated with strain S1450. A percentage of 13,3% mortality of H. armigera larvae fed in the inoculated plant were verified, but no symptoms of bacterial intoxication were observed. These results show that the use of Bt as colonizer and endophytic of plants has potential in the biological control of insect pests and as growth promotion of cotton plants.
Unidade Acadêmica:	Faculdade de Agronomia e Medicina Veterinária (FAV)
Informações adicionais:	Tese (doutorado) — Universidade de Brasília, Faculdade de Agronomia e Medicina Veterinária, Programa de Pós-Graduação em Agronomia, 2023.
Programa de pós-graduação:	Programa de Pós-Graduação em Agronomia
Licença:	A concessão da licença deste item refere-se ao termo de autorização impresso assinado pelo autor com as seguintes condições: Na qualidade de titular dos direitos de autor da publicação, autorizo a Universidade de Brasília e o IBICT a disponibilizar por meio dos sites www.unb.br, www.ibict.br, www.ndltd.org sem ressarcimento dos direitos autorais, de acordo com a Lei nº 9610/98, o texto integral da obra supracitada, conforme permissões assinaladas, para fins de leitura, impressão e/ou download, a título de divulgação da produção científica brasileira, a partir desta data.
Agência financiadora:	Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES).
Aparece nas coleções:	Teses, dissertações e produtos pós-doutorado

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