FROM Qutn TO Bt COTTON: DEVELOPMENT, ADOPTION AND PROSPECTS. A REVIEW

Area of Science:

• Agricultural Science
• Genetics
• Entomology

Background:

• Cotton is a vital global cash crop, with transgenic varieties offering significant advantages.
• Bacillus thuringiensis (Bt) Cry-toxins provide specific insecticidal properties, revolutionizing cotton cultivation.
• Rapid adoption of Bt cotton highlights its economic and environmental benefits.

Purpose of the Study:

• To investigate the variable expression of Bt transgenes in cotton grown in tropical environments.
• To understand the impact of genotypic and environmental interactions on Bt toxin levels.
• To address concerns regarding potential insect resistance development to Bt cotton.

Main Methods:

• Analysis of Bt transgene expression across different cotton genotypes and plant parts.
• Assessment of toxin levels at various plant life stages.
• Evaluation of environmental factors influencing transgene performance.
• Exploration of epigenetic effects on gene expression.

Main Results:

• Variable expression of Bt transgenes, including Cry1Ac, was observed in tropical environments.
• Toxin levels varied significantly between plant parts and developmental stages.
• Genotypic interactions with environmental factors contribute to expression variability.
• Sub-lethal toxin levels may promote resistance in target insect populations.

Conclusions:

• Variable Bt toxin expression in tropical cotton poses a risk of insect resistance.
• Strategies like gene stacking and Insect Resistance Management (IRM) are crucial for sustainable Bt cotton cultivation.
• Further research is needed to optimize Bt transgene expression and mitigate resistance development.