Characterization of a Bacillus thuringiensis delta-endotoxin which is toxic to insects in three orders

Citation
Ch. Zhong et al., Characterization of a Bacillus thuringiensis delta-endotoxin which is toxic to insects in three orders, J INVER PAT, 76(2), 2000, pp. 131-139
Citations number
45
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Animal Sciences
Journal title
JOURNAL OF INVERTEBRATE PATHOLOGY
ISSN journal
0022-2011 → ACNP
Volume
76
Issue
2
Year of publication
2000
Pages
131 - 139
Database
ISI
SICI code
0022-2011(200008)76:2<131:COABTD>2.0.ZU;2-8
Abstract
We report here the first Bacillus thuringiensis (Bt) toxin which is toxic t o insects from three insect orders (Diptera, Coleoptera, and Lepidoptera). An oligonucleotide probe based on the delta-endotoxin N-terminal sequence w as used to detect the gene. A 23-kb BamHI fragment containing the intact ge ne was identified and cloned from Bt strain YBT-226 plasmid DNA into the ve ctor pBluescript II. Through a series of DNA manipulations the size of this fragment was reduced and the gene sequenced. The deduced amino acid sequen ce gave a predicted molecular mass of 137 kDa and was identical to a cry1Ba protein from Bt subsp, thuringiensis HD-2, which is now designated as Cry1 Ba1 under a new classification scheme. This protein also showed 81.6% simil arity with the Cry1B protein (Cry1Bb1) from Bt strain EG 5847. When the YBT -226 cry1Ba1 gene was expressed in an acrystalliferous Bf subsp, israelensi s strain it produced irregular bipyramidal crystals during sporulation, whi ch reacted specifically with anti-Cry1Ba antiserum. Bioassays using these c rystals after purification resulted in significant mortality at. low to mod erate concentrations to larvae of the house fly (Musca domestica, Diptera), cottonwood leaf beetle (Chrysomela scripta, Coleoptera), and tobacco hornw orm (Manduca sexta, Lepidoptera), This broad-spectrum toxicity was not depe ndent on presolubilization, In assays with insect cell lines not derived fr om midgut cells, the soluble toxin killed CH1t (Manduca sexta cells) but wa s inactive against CF1 (Chorisfoneura fumiferana cells), Aa(s) (Aedes aegyp ti), and C2 (Culex quinquefasciatus) mosquito cells. (C) 2000 Academic Pres s.