Project Number: 5447-21220-005-08
Start Date: Sep 01, 2012
End Date: Aug 31, 2015
1) qPCR-based gut analysis will be applied to the corn arthropod community to generate a taxon-specific consumption index of corn tissue that is based on the frequency of consumption and the quantity of DNA consumed. A preliminary description of the corn arthropod community has produced gut-DNA extractions from 5,672 arthropods collected from corn fields of eastern South Dakota. We have developed and published primer sets that amplify a 141 bp fragment of the corn COI gene that is useful in determining which arthropods have consumed corn tissue through gut analysis. 2) Laboratory based assays will be used to administer a range of putative insecticidal RNAi that have been identified in the literature to three pests with different feeding ecologies: Tetranychus urticae, Spodoptera frugiperda and Rhopalosiphum padi. These pests will be fed to a suite of predators, each with their own feeding ecologies (e.g, Coleomegilla maculata, Orius insidiosus, and Chrysoperla carnea). The presence of the interference RNA molecules in the various insects will be assessed using targeted PCR. If interference RNA is found to be present in the predators, then an exposure analysis of key herbivores and their predator communities will be conducted using PCR-based gut analysis. 3) Of those species that are exposed to the RNAi-containing corn or prey, specific indicator taxa will be selected from key functional groups and their genomes will be sequenced and placed into a searchable database. Sequence homologies between current and future RNAi targets can be screened against this database for targeting non-target toxicity assays.