Data/hora: 12/06/2024 02:10:29

Biblioteca(s): | Embrapa Milho e Sorgo.
Tipo da produção científica: | Capítulo em Livro Técnico-Científico
Data corrente: | 20/01/2020
Data da última atualização: | 20/01/2020
Autoria: | VALICENTE, F. H.
Afiliação: | FERNANDO HERCOS VALICENTE, CNPMS.
Título: | Bacillus thuringiensis.
Ano de publicação: | 2019
Fonte/Imprenta: | In: SOUZA, B.; VÁZQUEZ, L. L.; MARUCCI, R. C. (Ed.). Natural enemies of insect pests in neotropical agroecosystems: biological control and functional biodiversity. Switzerland: Springer Nature, 2019.
Páginas: | p. 151-159.
DOI: | 10.1007/978-3-030-24733-1_13
Idioma: | Inglês
Conteúdo: | Bacillus thuringiensis (Bt) is an aerobic Gram-positive bacterium from the Bacillaceae family that produces protein crystalline inclusions named Cry proteins during the stationary phase encoded by different cry genes (Angus 1954; Bechtel and Bulla 1976). Bacillus thuringiensis is a ubiquitous bacterium that can be found in different substrates such as soil, water, plant surfaces, dead insects, grain dust, spiderwebs, and stored grain (Federici 1999; Glare and O?Callaghan 2000; Valicente and Barreto 2003). Crystal proteins are composed of one or more proteins, Cry or Cyt (cytolytic protein), and they are named delta (&#948;) endotoxins. These are the factors that determine Bt pathogenicity (Schnepf et al. 1998) and may show different forms as shown in Fig. 13.1 (Valicente and Souza 2004). Many Bt strains also produce other types of insecticidal proteins, such as the Vip proteins (vegetative insecticidal proteins) that are synthesized during the vegetative phase growth not forming any crystals, which were identified by Estruch et al. 1996. Some other important proteins are also produced, such as Cyt, &#946;-exotoxins, and Sip proteins. However, the most studied are the cry genes/Cry proteins. The identification of a Bt strain to subspecies is done using the flagellar antigen H, e.g., Bacillus thuringiensis sv kurstaki. However, this type of characterization does not consider the genes present in these strains, e.g., strain HD-1 (Bt sv kurstaki) harbors the genes cry1Aa, cry1Ab, cry1Ac, cry2A, and cry2B, and strain HD-73 (Bt sv kurstaki) harbors only cry1Ac gene. These toxic proteins from Bt are used in pest control as a biological pesticide or as transgenic plant expressing these proteins. This is a very useful and powerful tool in integrated pest management (IPM). In this work, we describe the genetic variability and molecular characterization of Bacillus thuringiensis, and the importance of finding the appropriate strain for a specific insect pest. We also provide the description of the Cry proteins and the nomenclature of Cry proteins, as well as their importance for insect specificity, their mode of action, and how Bacillus thuringiensis is used as biological pesticides.
Palavras-Chave: | Caracterização molecular; Pesticida biológico; Variabilidade genética.
Thesagro: | Bactéria; Controle Biológico; Praga de Planta.
Categoria do assunto: | H Saúde e Patologia
Registro original: | Embrapa Milho e Sorgo (CNPMS)
Exemplares: | CNPMS - (29100-1) - UPC - PL - DD -  -  -  - DIS