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ARS Home » Southeast Area » Fort Pierce, Florida » U.S. Horticultural Research Laboratory » Subtropical Insects and Horticulture Research » Research » Publications at this Location » Publication #268851
Title: Advances in RNA interference: dsRNA treatment in trees and grapevines for insect pest population suppression

Author
item Hunter, Wayne
item GLICK, EITAN - Beeologics, Llc
item PALDI, NITZAN - Beeologics, Llc
item BEXTINE, B - University Of Texas

Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/25/2011
Publication Date: 3/30/2012
Citation: Hunter, W.B., Glick, E., Paldi, N., Bextine, B. 2012. Advances in RNA interference: dsRNA treatment in trees and grapevines for insect pest population suppression. Southwestern Entomologist. 37(1): 85-87.

Interpretive Summary: RNA interference (RNAi) is a breakthrough technology that has significantly impacted contemporary approaches to control the damage caused by insect pests. Most well-known RNAi studies continue to rely on injecting the dsRNA molecules directly into the organism; this approach is not suitable for use in the field. If host-delivered RNAi-based management approaches are to be implemented, plants must successfully uptake the dsRNA and retain it long enough for the target insects to ingest it through feeding. This report entails current efforts of Highly Specific Pest Control (HiSPeC) substances that use plant-systemic delivery of the RNAi agent. Persistence of these species specific dsRNA’s fed to psyllids or leafhoppers were detectable for up to eight days post ingestion. Methods for treating the host plants, citrus trees or grapevines, resulted in the detection of these specific agents up to 57 days post treatment in citrus, and 24 days in grapevines. The longevity of the dsRNA in citrus trees showed that RNAi approaches may be suitable for development as an area-wide pest suppression strategy. This study reports the robust nature and persistence of the RNAi pathway metabolites in whole-plant systems targeting psyllids and leafhoppers.

Technical Abstract: RNA interference (RNAi) is a breakthrough technology that has significantly impacted contemporary approaches to control the damage caused by insect pests. Most well-known RNAi studies continue to rely on injecting the dsRNA molecules directly into the organism; this approach is not suitable for use in the field. If host-delivered RNAi-based management approaches are to be implemented, plants must successfully uptake the dsRNA and retain it long enough for the target insects to ingest it through feeding. This report entails use of plant-systemic delivery of the RNAi agent. Persistence of these species specific dsRNA’s fed to psyllids or leafhoppers were detectable for up to eight days post ingestion. Methods for treating the host plants, citrus trees or grapevines, resulted in the detection of these specific agents up to 57 days post treatment in citrus, and 24 days in grapevines. RNAi effects from species specific dsRNA’s, made to arginine kinase, under laboratory conditions, reduced survival of two psyllids species: Asian citrus psyllid, Diaphorina citri Kuwayama, and potato psyllid, Bactericera cockerelli (Sulc) (Hemiptera: Psyllidae), and the leafhopper species, glassy-winged sharpshooter, Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae). The increased mortality from RNAi worked in feeding assays of dsRNA’s in sucrose solutions, cut plant tissue absorption, and root absorption in citrus trees and grapevines. Introduced dsRNA was detected in Citrus trees, 6-year-old Mexican limes, approximately 2.5 m tall, 5 weeks post treatment, after a single treatment (2 g dsRNA in 15 L water). This is the first study which demonstrates the longevity of dsRNA in citrus trees which supports a RNAi approach suitable for development as an area-wide pest suppression strategy against hemipteran pests. This study reports the robust nature and persistence of the RNAi pathway metabolites in whole-plant systems targeting psyllids and leafhoppers.