Development and characterisation of transgenic rice expressing two Bacillus thuringiensis genes

Area of Science:

• Agricultural Science
• Genetics
• Entomology

Background:

• Transgenic Bacillus thuringiensis (Bt) crops, commercialized since 1996, face pest resistance challenges.
• Insect resistance management (IRM) strategies are crucial for sustainable Bt crop technology.
• Gene stacking, combining multiple Bt genes, is a promising IRM approach.

Purpose of the Study:

• To develop and characterize insect-resistant rice pyramided with two Bt genes.
• To evaluate the efficacy of stacked Bt genes against key rice pests.
• To assess the commercial viability and IRM potential of pyramided Bt rice.

Main Methods:

• Development of pyramided Bt rice lines through sexual crossing.
• Quantification of Bt toxin expression in single-gene and two-gene rice lines.
• Laboratory bioassays and field evaluations against Chilo suppressalis and other pests.

Main Results:

• Homozygous two-gene Bt rice lines were successfully generated.
• Stacked Bt gene expression was comparable to single-gene parents, with a noted decrease in cry1C.
• Pyramided lines demonstrated enhanced efficacy against stemborers and leaffolders in field trials.
• Yields of pyramided lines were comparable to conventional varieties under insecticide application.

Conclusions:

• The developed two-gene Bt rice lines exhibit significant commercial potential.
• Gene stacking serves as a valuable and effective IRM strategy for insect control in rice.
• This approach contributes to the sustainable deployment of Bt crop technology.