Manduca sexta (Lepidoptera: Sphingidae) cadherin fragments function as synergists for Cry1A and Cry1C Bacillus thuringiensis toxins against noctuid moths Helicoverpa zea, Agrotis ipsilon and Spodoptera exigua

• Published in: Pest management science 2009-10, Vol.65 (10), p.1097-1103
• Main Authors: Abdullah, Mohd Amir F, Moussa, Saad, Taylor, Milton D, Adang, Michael J
• Format: Article
• Language: English
• Subjects: Agrotis ipsilon; Amino Acid Sequence; Animals; Bacillus thuringiensis; Bacteria; Bacterial Proteins - pharmacology; binding proteins; Butterflies & moths; cadherin; cadherins; Cadherins - chemistry; Cadherins - genetics; Cadherins - metabolism; Cadherins - pharmacology; Cry toxin; crystal proteins; Drug Synergism; Endotoxins - pharmacology; Gene Expression; Helicoverpa zea; Heliothis virescens; Hemolysin Proteins - pharmacology; Insect Proteins - chemistry; Insect Proteins - genetics; Insect Proteins - metabolism; Insect Proteins - pharmacology; insecticidal proteins; Lepidoptera; Manduca - chemistry; Manduca - metabolism; Manduca sexta; microbial insecticides; Molecular Sequence Data; Moths - drug effects; Noctuidae; Pest control; Pesticide Synergists - chemistry; Pesticide Synergists - metabolism; Pesticide Synergists - pharmacology; protein subunits; protein-protein interactions; Sphingidae; Spodoptera exigua; synergists; Toxicity; Toxins
• ISSN: 1526-498X; 1526-4998; 1526-4998
• DOI: 10.1002/ps.1798

BACKGROUND: Specific Bacillus thuringiensis Berliner (Bt) toxins are effective against a narrow spectrum of species. While specificity is an advantage for limiting adverse effects on non-target organisms, it is also the primary drawback of Bt's application for controlling multiple pest species in agriculture, forestry and other areas. Recently, it was reported that a small toxin-binding fragment of Manduca sexta (Joh.) cadherin acts as a synergist of Bt toxins to M. sexta, Heliothis virescens F. and Helicoverpa zea (Boddie). These insects are quite susceptible to the Cry1A toxins. The first aim of the present study was to determine if longer-sized fragments of M. sexta cadherin differed in the level of toxin enhancement. The second aim was to examine enhancement of Bt toxins against relatively Bt-tolerant insects Agrotis ipsilon (Hufn.) and Spodoptera exigua (Hübner).RESULTS: Cadherin fragments longer than previously reported had improved synergistic properties. Significant enhancement of Bt Cry1A toxins against A. ipsilon and S. exigua was found. A cadherin fragment also increased Cry1C toxicity to S. exigua.CONCLUSIONS: The commercial development of this synergist has the potential to widen the spectrum of Bt toxicity to other important agricultural lepidopteran insect pests and thus increase its usefulness in agriculture.