Optimizing pyramided transgenic Bt crops for sustainable pest management

Area of Science:

• Agricultural Entomology
• Molecular Biology
• Genetics

Background:

• Transgenic crops producing Bacillus thuringiensis (Bt) toxins are crucial for insect pest control.
• Pyramiding two or more Bt toxins targeting the same pest is a key strategy to delay resistance evolution.
• Understanding the efficacy and limitations of current Bt toxin pyramids is vital for sustainable agriculture.

Purpose of the Study:

• To evaluate the effectiveness of current transgenic crop pyramids in managing insect pest resistance.
• To identify factors contributing to the failure or reduced efficacy of Bt toxin pyramids.
• To provide insights for designing improved pyramids and resistance management strategies.

Main Methods:

• Meta-analysis of 38 studies on ten Bt toxins against 15 insect pests.
• Assessment of insect survival rates on Bt toxin pyramids compared to optimal low survival.
• Analysis of cross-resistance and antagonism between different Bt toxins.

Main Results:

• Currently used Bt pyramids often result in higher survival rates for both susceptible and resistant insects than expected.
• Cross-resistance and antagonism between Bt toxins within pyramids are frequently observed.
• Toxin similarity in domains II and III correlates with cross-resistance and antagonism, respectively.

Conclusions:

• Existing Bt toxin pyramids may not be as effective as intended in delaying pest resistance.
• Structural similarities between Bt toxins can lead to negative interactions, compromising resistance management.
• Future pyramid design should consider toxin similarity to mitigate cross-resistance and antagonism for sustainable pest control.