Protein engineering of Bacillus thuringiensis δ-endotoxin

Issue Date

10-2011

Abstract

Bacillus thuringiensis Cry1Ab δ-endotoxin is toxic to many insect pests and is one of the components of the active ingredients of commercial Bt preparations. Cry1Ab is also expressed as a transgenic protein in many commercial genetically modified crops such as Bt corn. The development of insect resistance to Cry1Ab is a major concern to various stakeholders for obvious economic reasons. This research project was conducted to test the hypothesis that protein engineering can be employed to improve the toxicity of Cry1Ab δ-endotoxin to the diamondback moth Plutella xylostella L., a major insect pest of crucifers. Loop 2 domain II of Cry1Ab δ-endotoxin was targeted for site-directed mutagenesis because it is involved in receptor binding. Site-directed mutations were introduced in loop 2 of domain II of Cry1Ab δ-endotoxin. Mutations were toxicity to 3-day old P. xylostella larvae. Leaf dip assays were conducted using cabbage leaves. Results of bioassays showed that the mutant F371P had more than 500-fold and 3000-fold increase in potency to the Benguet population of P. xylostella larvae as compared to the wild type protein, and to the commercial preparation (Dipel), respectively.

Source or Periodical Title

Philippine Entomologist

ISSN

0048-3753

Volume

25

Issue

2

Page

175-186

Document Type

Article

Frequency

semi-annually

Physical Description

illustrations; tables

Language

English

En – AGROVOC descriptors

PLUTELLA XYLOSTELLA; BACILLUS THURINGIENSIS; ENDOTOXINS; MUTATION; MUTAGENESIS; PEST RESISTANCE

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