Phenotypic effects of PBAN RNAi using oral delivery of dsRNA to corn earworm (Lepidoptera: Noctuidae) and tobacco budworm larvae

Authors: Choi, Man-Yeon; Vander Meer, Robert - Bob

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/29/2018
Publication Date: 12/3/2018
Citation: Choi, M.Y., Vander Meer, R.K. 2018. Phenotypic effects of PBAN RNAi using oral delivery of dsRNA to corn earworm (Lepidoptera: Noctuidae) and tobacco budworm larvae. Journal of Economic Entomology. 112(1):434-439. https://doi.org/10.1093/jee/toy356.
DOI: https://doi.org/10.1093/jee/toy356

Interpretive Summary: RNA interference (RNAi) is a gene silencing mechanism using double-stranded RNA (dsRNA), that now provides a new avenue for insect pest management. Recently, intensive RNAi study on Lepidopeteran moths the RNAi technology looks very promising to control pest moths. For successful RNAi control applications the identification of a suitable target gene and/or physiological system is a critical. Insect neuropeptides are the largest group of insect hormones. A variety of peptide families have been identified from insects, that offer potential for pest control. One of these families is the pheromone biosynthesis activating neuropeptide (PBAN)/pyrokinin family defined by a conserved C-terminal pentapeptide, that involved in multiple physiological functions, making it a good RNAi target. Helicoverpa and Heliothis moths are major lepidopteran pests of many economically important crops including corn, cotton, soybean, green and hot peppers, tomatoes, and potatoes throughout the world. Currently, major control tools for these species rely on chemical insecticides and/or Bt transgenic, but these methods are continuously encountering insecticide resistance and non-target toxicity. Scientists from USDA-ARS, Corvallis, OR and Gainesville, FL, developed an oral delivery of dsRNA to Corn earworm, Helicoverpa zea, and Tobacco budworm, Heliothis virescens larvae, and identified various RNAi impacts, including larval delayed growth, incomplete pupal development, and mortality on the moths. The research result in the multifunctional roles demonstrated for the these peptides that show the potential of this RNAi target gene as an RNAi-based control method.

Technical Abstract: Insect neuropeptides represent more than 90% of all insect hormones. The pheromone biosynthesis activating neuropeptide (PBAN)/pyrokinin family is a major group of insect neuropeptides. These neuropeptides regulate a variety of biological functions related to sex pheromone biosynthesis and diapause from embryo to adult in moths, but other potential functions are yet to be determined. Successful RNAi application requires the identification of a suitable targets through a screening process. Insect neuropeptide genes including PBAN are known to have multiple functions and could be a good RNAi target. In this study, we selected the PBAN gene and its neuropeptide products as an RNAi target for two economically important moth species, the corn earworm, Helicoverpa zea, and the tobacco budworm, Heliothis virescens. We investigated RNAi effects on these immature moths that had ingested the specific dsRNA starting at the 1st instar larva until pupation. We report and discuss resulting delay of larval growth, interference of pupal development, and mortality in the two pest moth species. In addition, we selected small interfering RNAs (siRNAs) to determine if they have negative phenotypic effects similar to their full length RNAi parents. This is one of the few examples of negative RNAi effects on lepidopteran pests via feeding and suggests possible RNAi-based control of pest moths.