Parallel evolution of Bacillus thuringiensis toxin resistance in lepidoptera

Area of Science:

• Agricultural entomology
• Molecular biology
• Biochemistry

Background:

• Bacillus thuringiensis (Bt) produces insecticidal toxins widely used in agriculture.
• The precise molecular mechanisms underlying Bt toxin action and insect resistance are not completely elucidated.
• Understanding these mechanisms is vital for sustainable pest management and combating resistance.

Purpose of the Study:

• To identify genetic factors conferring resistance to Bacillus thuringiensis (Bt) Cry1Ac toxin in lepidopteran pests.
• To elucidate the role of specific membrane transporters in the mode of action of Bt toxins.

Main Methods:

• Genetic mapping was employed to identify the gene locus associated with Bt Cry1Ac resistance.
• Comparative analysis was performed across two lepidopteran species exhibiting resistance.
• The function of the identified membrane transporter was investigated in relation to Bt toxin activity.

Main Results:

• Genetic mapping successfully localized a key resistance locus.
• The ATP-binding cassette sub-family C member 2 (ABCC2) gene was identified at this locus.
• ABCC2 was strongly implicated as a critical membrane transporter involved in Bt Cry1Ac toxin action and resistance.

Conclusions:

• The ABCC2 protein plays a significant role in the mechanism of Bacillus thuringiensis Cry1Ac toxin.
• Identification of ABCC2 provides new insights into Bt toxin resistance in lepidopterans.
• This finding advances our understanding of Bt-insect interactions and has implications for pest control strategies.