Inhibitor of apoptosis is an effective target gene for RNAi‐mediated control of Colorado potato beetle, Leptinotarsa decemlineata

• Published in: Archives of insect biochemistry and physiology Vol. 104; no. 4; pp. e21685 - n/a
• Main Authors: Máximo, Wesley P. F., Howell, Jeffrey L., Mogilicherla, Kanakachari, Basij, Moslem, Chereddy, Shankar C. R. R., Palli, Subba R.
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01-08-2020
• Subjects: Actin; Adults; Alkaloids; Apoptosis; CPB; Double-stranded RNA; dsActin; dsIAP; dsRNA; E coli; Gene expression; Genes; Immune response; Inhibitors; Insecticide resistance; Insecticides; Insects; Larvae; Leptinotarsa decemlineata; Mortality; Pest control; Pests; Potatoes; Ribonucleic acid; RNA; RNA viruses; RNA-mediated interference; RNAi; Target recognition; Toxins; Vegetables; United States > US; Colorado; dsRNA; RNAi; CPB; dsActin; dsIAP
• ISSN: 0739-4462; 1520-6327
• DOI: 10.1002/arch.21685

The Colorado potato beetle (CPB; Leptinotarsa decemlineata) is one of the most notorious and difficult to control pests of potato and other solanaceous crops in North America. This insect has evolved a remarkable ability to detoxify both plant and synthetic toxins, allowing it to feed on solanaceous plants containing toxic alkaloids and to develop resistance to synthetic chemicals used for its control. RNA interference (RNAi) is a natural mechanism that evolved as an immune response to double‐stranded RNA (dsRNA) viruses where dsRNA triggers silencing of target gene expression. RNAi is being developed as a method to control CPB. Here, we evaluated four CPB‐specific genes to identify targets for RNAi‐mediated control of this insect. Out of the four dsRNAs evaluated in CPB larvae and adults, dsIAP (dsRNA targeting inhibitor of apoptosis, iap gene) performed better than dsActin, dsHSP70, and dsDynamin in inducing larval mortality. However, in adults, the mortality induced by dsActin is significantly higher than the mortality induced by dsIAP, dsHSP70, and dsDynamin. Interestingly, a combination of dsIAP and dsActin performed better than either dsIAP or dsActin alone by inducing feeding inhibition in 24 hr and mortality in 48 hr in larvae. When the dsIAP and dsActin were expressed in the Escherichia coli HT115 strain and applied as a heat‐killed bacterial spray on potato plants, it protected the plants from CPB damage. These studies show that the combination of dsIAP and dsActin shows promise as an insecticide to control CPB.
The Colorado potato beetle (CPB) larvae were fed on potato leaf discs treated with dsGFP, dsActin, dsIAP, or dsIAP plus dsActin daily for 4 days. The photographs were taken at 96hr after treatment.
Research Highlights
A combination of double‐stranded RNAs targeting inhibitor of apoptosis and actin genes induced feeding inhibition and mortality in the Colorado potato beetle (CPB) larvae. This combination has potential as an insecticide to control CPB.