RNAi-based gene silencing through dsRNA injection or ingestion against the African sweet potato weevil Cylas puncticollis (Coleoptera: Brentidae).
BACKGROUND
RNA interference (RNAi) technology can potentially serve as a suitable strategy to control the African sweet potato weevil Cylas puncticollis (SPW), which is a critical pest in sub-Saharan Africa. Important prerequisites are required to use RNAi in pest control, such as the presence of an efficient RNAi response and the identification of suitable target genes.


RESULTS
Here we evaluated the toxicity of dsRNAs targeting essential genes by injection and oral feeding in SPW. In injection assays, 12 of 24 dsRNAs were as toxic as the one targeting Snf7, a gene used commercially against Diabrotica virgifera virgifera. Three dsRNAs with high insecticidal activity were then chosen for oral feeding experiments. The data confirmed that oral delivery can elicit a significant toxicity, albeit lower compared with injection. Subsequently, ex vivo assays revealed that dsRNA is affected by degradation in the SPW digestive system, possibly explaining the lower RNAi effect by oral ingestion.


CONCLUSIONS
We conclude that the full potential of RNAi in SPW is affected by the presence of nucleases. Therefore, for future application in crop protection, it is necessary constantly to provide new dsRNA and/or protect it against possible degradation in order to obtain a higher RNAi efficacy. © 2016 Society of Chemical Industry.
Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.|Department of Molecular Biotechnology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.|International Potato Centre (CIP), Genomics and Biotechnology Programme, Nairobi, Kenya.
Katterinne
K
Prentice
Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.
Olivier
O
Christiaens
International Plant Biotechnology Outreach, VIB, Ghent, Belgium.
Ine
I
Pertry
Venganza Inc., St Augustine, FL, USA.
Ana
A
Bailey
Venganza Inc., St Augustine, FL, USA.
Chuck
C
Niblett
International Potato Centre (CIP), Genomics and Biotechnology Programme, Nairobi, Kenya.
Marc
M
Ghislain
Department of Molecular Biotechnology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.
Godelieve
G
Gheysen
Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.
Guy
G
Smagghe
D000818:Animals; D027723:Ipomoea batatas; D010572:Pest Control, Biological / Q000379:methods*; D034622:RNA Interference; D012330:RNA, Double-Stranded; D048889:Weevils
D012330:RNA, Double-Stranded
African sweet potato weevil; Cylas puncticollis; RNAi interference; dsRNA degradation; injection; oral feeding