Molecular Mechanisms of Diapause In The Corn Rootworm Complex

The corn rootworm complex is a serious pest of Midwest corn crops, with an estimated annual economic impact >$1 billion. The two primary rootworm pests in the Corn Belt are the western corn rootworm (WCR), Diabrotica virgifera virgifera Leconte and the northern corn rootworm (NCR), Diabrotica barberi Smith & Lawrence. Both of these species are univoltine and undergo an obligate embryonic diapause to survive winter conditions and synchronize their life cycles with their food source. Despite the central role of diapause in the rootworm life cycle, the underlying mechanisms of diapause in this species complex have not been investigated. Our project will fill this gap by identifying and characterizing genes that regulate diapause in both WCR and NCR. This information will benefit industry by facilitating the creation of nondiapausing rootworm strains and providing new targets for pest control. Our project will identify targets that can be mutated (e.g., with CRISPR/Cas9) to create rootworm strains that avert diapause. Currently, a nondiapausing strain of NCR is unavailable, and the widely used WCR lab strain took several years of mass selection to create. The ability to create nondiapausing strains through genetic manipulation would allow for the rapid, cost-effective creation of genetically distinct lab populations for testing bioactives. Furthermore, the ability to genetically or chemically manipulate diapause as a pest control strategy holds great promise, but these approaches have not been pursued in rootworms due to the current lack of information on diapause in this complex. Finally, this project will create the first comprehensive transcriptomic database for NCR (to our knowledge) and will add to the growing genetic resources for WCR