Double strand RNA oral delivery methods to induce RNA interference in phloem and plant-sap-feeding insects

Authors: Ghosh, Saikat Kumar; Gundersen-Rindal, Dawn; Park, Alexis; Hunter, Wayne

Submitted to: Journal of Visualized Experiments
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/9/2018
Publication Date: 5/4/2018
Citation: Ghosh, S.B., Gundersen, D.E., Park, A.L., Hunter, W.B. 2018. Double strand RNA oral delivery methods to induce RNA interference in phloem and plant-sap-feeding insects. Journal of Visualized Experiments. https://doi.org/10.3791/57390.
DOI: https://doi.org/10.3791/57390

Interpretive Summary: The brown marmorated stink bug (BMSB) is an invasive insect pest feeding avidly on agricultural and other specialty crops. This insect also invades houses, schools and other indoor spaces that provide a safe hiding area for mating and laying eggs. BMSB may also cause an allergic reaction in individuals sensitive to its allergens. In order to manage this pest, we have successfully tested a new biotechnology called RNA interference (RNAi) that may cause a negative impact on an insect and therefore useful for control. All earlier reports of RNAi in BMSB have used injection of genetic material into the insect. This is impractical for agricultural use because it is necessary for insects to ingest genetic material through feeding in order to be used in the environment. BMSB feeds by inserting its needle like stylet into the tissue of the fruits and crops; sucking the phloem causing damage. This feeding method for delivering genetic material through green beans immersed in solution containing genetic material is visually demonstrated in this manuscript. This information will be of assistance to scientists and companies that are interested in delivering treatments for developing new strategies for management of insect pests such as BMSB.

Technical Abstract: Phloem and plant sap feeding insect pests invade the integrity of crops and fruits to retrieve nutrients in the process damaging food productivity. Hemipteran insects account for a number of economically substantial pests of plants that cause damage to crops by feeding on phloem sap. Halyomorpha halys (Heteroptera: Pentatomidae), the brown marmorated stink bug (BMSB), is an invasive hemipteran insect pest introduced in to North America, where it is both an invasive agricultural pest of high value specialty, row, and staple crops, as well as an indoor nuisance pest. Significant ecological and economic constraint caused by BMSB may extend collectively to billions of dollars. Insecticide resistance in many species has led to the development of alternate methods of pest management strategies. Double-stranded RNA (dsRNA)-mediated RNA interference (RNAi) is a gene silencing mechanism for functional genomic studies and represents a potential tool for the management of insect pests. Exogenously synthesized dsRNA or siRNA can trigger highly efficient gene silencing through the degradation of endogenous RNA homologous to the presented siRNA. Effective and environmental use of RNAi as molecular biopesticides for biocontrol of hemipteran insects like BMSB in the environment requires the in vivo delivery of dsRNAs through feeding. Here we have demonstrated that dsRNA may be loaded in green beans by immersing and absorbing BMSB gene specific dsRNA for per os delivery for sustained release. This novel delivery system efficiently delivered an effective dosage to induce a significant decrease in expression of targeted genes such as JHAMT and Vg. This state-of-the-art innovation translates strategies developed for delivery of dsRNA and overcome environmental challenges for pest management to use in crop protection.