Cry75Aa (Mpp75Aa) Insecticidal Proteins for Controlling the Western Corn Rootworm, Diabrotica virgifera <i>virgifera</i> LeConte (Coleoptera: Chrysomelidae), Isolated from the Insect-Pathogenic Bacterium Brevibacillus laterosporus

Abstract

This study describes three closely related proteins, cloned from <i>Brevibacillus laterosporus</i> strains, that are lethal upon feeding to <i>Diabrotica virgifera virgifera</i> LeConte, the western corn rootworm (WCR). Mpp75Aa1, Mpp75Aa2 and Mpp75Aa3 were toxic to WCR larvae when fed purified protein. Transgenic plants expressing each mMpp75Aa protein were protected from feeding damage and showed significant reduction in adult emergence from infested plants by both susceptible and Cry3Bb1 and Cry34Ab1/Cry35Ab1-resistant WCR. These results demonstrate that proteins from <i>B. laterosporus</i> are as efficacious as the well-known <i>Bacillus thuringiensis</i> (<i>Bt</i>) insecticidal proteins in controlling major insect pests such as WCR. The deployment of transgenic maize expressing mMpp75Aa along with other active molecules lacking cross-resistance have the potential to be a useful tool for control of WCR populations resistant to current <i>Bt</i> traits.<b>IMPORTANCE</b> Insects feeding on roots of crops can damage the plant roots resulting in yield loss due to poor water and nutrient uptake and plant lodging. In maize the western corn rootworm (WCR) can cause severe damage to the roots resulting in significant economic loss for farmers. Genetically modified (GM) expressing <i>Bacillus thuringiensis</i> (<i>Bt</i>) insect control proteins, has provided a solution for control of these pests. In recent years populations of WCR resistant to the <i>Bt</i> proteins in commercial GM maize have emerged. There is a need to develop new insecticidal traits for the control of WCR populations resistant to current commercial traits. New proteins with commercial level efficacy on WCR from sources other than <i>Bt</i> are becoming more critical. The Mpp75Aa proteins, from <i>B. laterosporus</i>, when expressed in maize, are efficacious against the resistant populations of WCR and have the potential to provide solutions for control of resistant WCR.