| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4557728 | Journal of Invertebrate Pathology | 2014 | 8 Pages |
•Co-expression of cry2Ab27 with cry1 genes led to amorphous crystal toxin formation.•Cry1 and Cry2Ab27 were co-crystallized in purified amorphous crystal toxins.•Toxin of SPC2 was 6.9-fold higher toxicity against H. armigera compared to SPHT.
The unexpressed cry2Ab27 gene of Bacillus thuringiensis subsp. aizawai SP41 (SP41) consists of a single open reading frame (ORF) of 1902 bp encoding for 634 amino acid residues. The cry2Ab27 gene appears to be silent due to the lack of promoter and terminator sequences. In this study we fused the cry2Ab27 ORF with the cry1Ab promoter (500 bp) and the terminator (300 bp) in vector pHT304-18Z in order to drive the expression of cry2Ab27 in both SP41 and an acrystaliferous, B. thuringiensis subsp. thuringiensis 407 (407). A protein with a molecular mass of 65 kDa, consistent with the Cry2Ab protein, was detected in both transformants using SDS–PAGE and Western blot analysis. Bipyramidal crystals were observed in SP41 and its transformant containing the pHT304-18Z vector (SPHT) in contrast, cells expressing cry2Ab27 (SPC2) exhibited crystal proteins with irregular shapes. No inclusion protein was detected in the 407 transformant expressing the cry2Ab27 gene. Cry2Ab27 was found in the purified crystal toxin from strain SPC2. The solubilized crystal toxin proteins from SPC2 were 6.9-fold more toxic toward the larvae of Helicoverpa armigera compared to toxin proteins from SPHT. However SPC2 crystal toxin displayed only slightly higher toxicity against the larvae of Spodoptera litura and S. exigua compared to SPHT produced toxin. Our data support the use of Cry2Ab in combination with the Cry1 toxin for enhanced control of heliothine insect pests.
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