Cry2A toxins from Bacillus thuringiensis expressed in insect cells are toxic to two lepidopteran insects
Autor(es): Lima, G. M. S.; Aguiar, R. W. S.; Correa, R. F. T.; Martins, E. S.; Gomes, A. C. M.; Nagata, T.; De-Souza, M. T.; Monnerat, R. G.; Ribeiro, B. M.
Resumo: The cry2Aa and cry2Ab genes from a Brazilian Bacillus thuringiensis strain were introduced into the genome of the baculovirus Autographa californica multiple nucleopolyhedrovirus (AcMNPV) in order to evaluate the heterologous proteins expression in insect cells and their toxicity to different insects. The recombinant viruses (vAcCry2Aa and vSynCry2Ab) were amplified in Trichoplusia ni (BTI-Tn5B1-4) cells and used to infect Spodoptera frugiperda larvae. Total extracts from S. frugiperda infected with the recombinant viruses were analysed by SDS-PAGE, which detected the presence of polypeptides around 65kDa. Cuboid-shaped protein crystals were observed in insect extracts by light and scanning electron microscopy. Bioassays, using the heterologous proteins showed toxicity against second instar A. gemmatalis larvae (Cry2Aa) with a LC sub(50) of 1.03kg/ml and second instar S. frugiperda larvae (Cry2Ab) with a LC sub(50) of 3.45kg/ml. No toxic activity was detected for Aedes aegypti and Culex quinquenfaciatus.
Palavras-Chave: Recombinants; Biological control; Instars; Insect larvae; Viruses; Toxicity; Toxicity tests; Mortality causes; Genomes; Scanning electron microscopy; Insect cells; Crystals; Toxins
Imprenta: World Journal of Microbiology & Biotechnology, v. 24, p. 2941-2948, 2008.
Descritores: Aedes aegypti - Cell ; Aedes aegypti - Proteins ; Aedes aegypti - Virus
Data de publicação: 2008
