Liposome encapsulation and EDTA formulation of dsRNA targeting essential genes increase oral RNAi-caused mortality in the Neotropical stink bug Euschistus heros

Pest Manag Sci. 2019 Feb;75(2):537-548. doi: 10.1002/ps.5167. Epub 2018 Oct 3.

Abstract

Background: The Neotropical stink bug Euschistus heros is a major pest in soybean fields. Development of highly species-specific pesticides based on RNA interference (RNAi) could provide a new sustainable and environmentally friendly control strategy.

Results: Here, the potential of RNAi as a pest control tool against E. heros was assessed. First, target gene selection using a microinjection approach was performed. Seven of the 15 candidate genes tested exhibited > 95% mortality after hemolymph injection of 27.5 ng dsRNA. Subsequently, dsRNA was administered orally using different formulations: naked dsRNA, liposome-encapsulated-dsRNA and dsRNA formulated with EDTA. Liposome-encapsulated dsRNA targeting vATPase A and muscle actin led to significant mortality after 14 days (45% and 42%, respectively), whereas EDTA-formulated dsRNA did so for only one of the target genes. Ex vivo analysis of the dsRNA stability in collected saliva indicated a strong dsRNA-degrading capacity by E. heros saliva, which could explain the need for dsRNA formulations.

Conclusion: The results demonstrate that continuous ingestion of dsRNA with EDTA or liposome-encapsulated dsRNA can prevent dsRNA from being degraded enzymatically and suggest great potential for using these formulations in dsRNA delivery to use RNAi as a functional genomics tool or for pest management of stink bugs. © 2018 Society of Chemical Industry.

Keywords: EDTA; Euschistus heros; Hemiptera, Pentatomidae; Lipofectamine® 2000; RNA interference; dsRNA ingestion.

MeSH terms

  • Animals
  • Edetic Acid / administration & dosage*
  • Heteroptera / genetics
  • Heteroptera / growth & development
  • Heteroptera / physiology*
  • Insect Control / methods*
  • Liposomes / administration & dosage*
  • Longevity
  • Nymph / genetics
  • Nymph / growth & development
  • Nymph / physiology*
  • RNA Interference*
  • RNA, Double-Stranded / chemistry*
  • Saliva / chemistry

Substances

  • Liposomes
  • RNA, Double-Stranded
  • Edetic Acid