Department of Biochemistry, Biophysics and Molecular Biology - Iowa State University

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Host:  Dipali Sashital

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"Knockdown of RNAi Pathway Genes Impacts the Fitness of Western Corn Rootworm"

Western corn rootworm (Diabrotica virgifera virgifera) is a serious agricultural pest known for its high adaptability to various management strategies, giving rise to a continual need for new control options.  Transgenic maize expressing insecticidal RNAs represents a novel mode of action for rootworm management that depends on the RNA interference (RNAi) pathways of the insect for efficacy.  Preliminary evidence suggests that western corn rootworm could develop resistance to insecticidal RNAs through changes in RNAi pathway genes; however, the likelihood of field-evolved resistance occurring through this mechanism remains unclear. 

I will present results of identification and targeted knockdown of eight key genes involved in facilitating interference through the microRNA and small-interfering RNA pathways in western corn rootworm.  Depletion of targeted transcripts in rootworm larvae altered microRNA expression, decreased ability to pupate, reduced adult beetle emergence, and diminished reproductive capacity.  These observed effects do not support evolution of resistance through changes in expression of these eight genes due to reduced insect fitness.