Disabled insecticidal proteins: A novel tool to understand differences in insect receptor utilization

Area of Science:

• Agricultural entomology
• Molecular biology
• Biochemistry

Background:

• Insect resistance to pesticides and crop protection traits is a major agricultural challenge.
• Novel insecticidal proteins (IPs) with alternative mechanisms of action (MOA) are needed to combat resistance.
• Understanding MOA and receptor binding is crucial for stacking IPs in crops to delay resistance.

Purpose of the Study:

• To introduce and validate the Disabled Insecticidal Protein (DIP) method for rapid differentiation of insecticidal protein MOA.
• To assess the DIP method's effectiveness in determining receptor binding preferences of IPs.

Main Methods:

• The Disabled Insecticidal Protein (DIP) method was applied to known insecticidal proteins from Bacillus thuringiensis.
• DIPs, containing non-toxic mutations, were co-administered with active IPs in insect feeding assays.
• The suppression of insecticidal activity indicated shared receptor binding and MOA.

Main Results:

• The DIP method successfully differentiated receptor binding preferences for a set of insecticidal proteins (Cry1Ab3, Cry1Ac.107, Cry2Ab2, Cry1Ca, Cry1A.105, and Cry1A.1088).
• Results were consistent with previous MOA studies, validating the DIP method's accuracy.
• DIPs acted as antidotes when co-administered with IPs sharing the same insect receptors.

Conclusions:

• The DIP methodology provides a robust and effective means for rapid MOA differentiation of insecticidal proteins.
• This technique supports the strategic stacking of insecticidal proteins in crops for enhanced and durable pest resistance.