Expression of the crystal protein gene under the control of the alpha-amylase promoter in Bacillus thuringiensis strains

Abstract

The expression of an insecticidal crystal protein gene of Bacillus thuringiensis under the control of the a-amylase gene promoter was investigated. The crylC gene, which encodes a protein known to have a unique activity against Spodoptera (armyworm) species, was used in this investigation. The cryIC gene was placed, along with the a-amylase promoter from B. subtilis, in a B. thuringiensis-derived cloning vector, generating a pair of recombinant plasmids, pSB744 and pSB745. The cloning vector that contains the minimal replicon of B. thuringiensis subsp. kurstaki HD73 is stably maintained in a variety of B. thuringiensis strains, as previously reported by Gamel and Piot (Gene 120:17-26, 1992). The present study confirmed that the recombinant plasmids are also stably maintained in B. thuringiensis subsp. kurstaki Cry-B and HD73 growing in media without selection pressure for at least 48 h. The cryIC gene on the recombinant plasmids were notably

Selection and characterization of Bacillus thuringiensis strains from northwestern Himalayas toxic against Helicoverpa armigera

“…The average Bt index recorded in the study was 0.62, which means that 62% of the sporulating colonies examined showed the presence of crystals. The average is higher compared to some previous isolation programs (less than 0.1 to 0.52) (Bravo et al., ; Chak, Tsen, & Yamamoto, ; Vidal‐Quist, Castañera, & González‐Cabrera, ), lower compared to that observed (0.85) by Martin and Travers () and similar to that observed (0.6 to 0.7) by Obeidat, Hassawi, and Ghabeish (). Lake sediments showed the least Bt index (0.25), whereas forest soils showed the highest Bt index (0.76) (Table ).…”

Bacillus thuringiensis and Its Pesticidal Crystal Proteins

“…A variety of shuttle vectors, some employing B. thuringiensis plasmid replicons (17,28,63,122), has been used to introduce cloned cry genes into B. thuringiensis (124). Alternatively, integrational vectors have been used to insert cry genes by homologous recombination into resident plasmids (2,219) or the chromosome (176).…”

Synergistic activity of a Bacillus thuringiensis delta-endotoxin and a bacterial endochitinase against Spodoptera littoralis larvae

“…It has been shown that C-terminally truncated versions of different Cry proteins and even 5Ј translational fusions with nptII are capable of exerting the insecticidal effect as long as the specific trypsin cleavage sites which delimit the toxin are maintained (16,32,46,48). The strict specificity of the receptor-toxin interaction has promoted the use of cry genes as very promising tools to construct insecticidal bacteria and transgenic plants with specific insect resistance (6,12,25,28). While in cry-carrying bacteria and plant chloroplasts (25) high levels of Cry proteins have been recorded, the native cry genes were poorly expressed as plant nuclear transgenes, and consequently their larvicidal activity was limited (12).…”