Genetically modifying the insect gut microbiota to control Chagas disease vectors through systemic RNAi

PLoS Negl Trop Dis. 2015 Feb 12;9(2):e0003358. doi: 10.1371/journal.pntd.0003358. eCollection 2015 Feb.

Abstract

Technologies based on RNA interference may be used for insect control. Sustainable strategies are needed to control vectors of Chagas disease such as Rhodnius prolixus. The insect microbiota can be modified to deliver molecules to the gut. Here, Escherichia coli HT115(DE3) expressing dsRNA for the Rhodnius heme-binding protein (RHBP) and for catalase (CAT) were fed to nymphs and adult triatomine stages. RHBP is an egg protein and CAT is an antioxidant enzyme expressed in all tissues by all developmental stages. The RNA interference effect was systemic and temporal. Concentrations of E. coli HT115(DE3) above 3.35 × 10(7) CFU/mL produced a significant RHBP and CAT gene knockdown in nymphs and adults. RHBP expression in the fat body was reduced by 99% three days after feeding, returning to normal levels 10 days after feeding. CAT expression was reduced by 99% and 96% in the ovary and the posterior midgut, respectively, five days after ingestion. Mortality rates increased by 24-30% in first instars fed RHBP and CAT bacteria. Molting rates were reduced by 100% in first instars and 80% in third instars fed bacteria producing RHBP or CAT dsRNA. Oviposition was reduced by 43% (RHBP) and 84% (CAT). Embryogenesis was arrested in 16% (RHBP) and 20% (CAT) of laid eggs. Feeding females 105 CFU/mL of the natural symbiont, Rhodococcus rhodnii, transformed to express RHBP-specific hairpin RNA reduced RHBP expression by 89% and reduced oviposition. Modifying the insect microbiota to induce systemic RNAi in R. prolixus may result in a paratransgenic strategy for sustainable vector control.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Carrier Proteins / genetics
  • Catalase / genetics
  • Chagas Disease / prevention & control*
  • Escherichia coli / genetics
  • Female
  • Gastrointestinal Microbiome / genetics*
  • Gastrointestinal Tract / microbiology*
  • Gene Knockdown Techniques
  • Genetic Vectors
  • Heme / metabolism
  • Heme-Binding Proteins
  • Hemeproteins / genetics
  • Insect Control / methods*
  • Insect Vectors / microbiology*
  • RNA Interference*
  • RNA, Double-Stranded
  • RNA, Small Interfering / genetics
  • Rhodnius / microbiology*
  • Trypanosoma cruzi / pathogenicity

Substances

  • Carrier Proteins
  • Heme-Binding Proteins
  • Hemeproteins
  • RNA, Double-Stranded
  • RNA, Small Interfering
  • Heme
  • Catalase

Grants and funding

The work was made possible by funding to PMP from Fondo Nacional de Ciencia y Tecnología, -FONACYT- of the National Secretariat for Science and Technology - SENACYT- and the support of the National Council for Science and Technology -CONCYT- of Guatemala. CL received funding from the Latin American and Caribbean Research Exchange Grant to support CU. This work was also supported by grants from the Conselho Nacional de Desenvolvimento Científico e Tecnológico, the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, the Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, the Programa de Apoio a Núcleos de Excelência, and the Howard Hughes Medical Institute. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.