Optimizing Efficient RNAi-mediated Control of Hemipteran Pests (Psyllids, Leafhoppers, Whitefly): Modified Pyrimidines in dsRNA Triggers

Authors: Hunter, Wayne; Wintermantel, William - Bill

Submitted to: Plants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/23/2021
Publication Date: 8/26/2021
Citation: Hunter, W.B., Wintermantel, W.M. 2021. Optimizing Efficient RNAi-mediated Control of Hemipteran Pests (Psyllids, Leafhoppers, Whitefly): Modified Pyrimidines in dsRNA Triggers. Plants. https://doi.org/10.3390/plants10091782.
DOI: https://doi.org/10.3390/plants10091782

Interpretive Summary: ARS researchers showed that by incorporating modified pyrimidines into Ribonucleic acid interference (RNAi) double-stranded RNA trigger molecules resulted in significantly increased hemipteran pest mortality. The three insect vectors studied in this report threaten global food security and included: The Asian citrus psyllid (ACP), Diaphorina citri, the vector of the Candidatus Liberibacter asiaticus bacterium that causes, Huanglongbing disease (HLB, also known as citrus greening disease)in citrus the Glassy-winged sharpshooter Homalodisca vitripennis, that is a major vector of the Xylella fastidiosa bacterium that causes Pierce's Disease of grapevines, that is currently threatening olive production in the Middle East; and the Silverleaf Whitefly, Bemisia tabaci, which is the vector for numerous viral plant pathogens, including Begomoviruses, Criniviruses, and others that infect over 100 different crop plants (i.e. bean, lentil, tomato, peppers, etc.). RNAi biopesticides degrade in the environment and are specific to the insect pest and thus do not harm beneficial insects, like bees. The significant increase in insect mortality when the modified nucleotides are used was demonstrated in insect pests including psyllids, leafhoppers, and whiteflies and brings the RNAi strategy for pest insect control one step closer to what is needed to be competitive with commercial broad-spectrum chemical insecticides. Support in part from 'The Citrus Greening Solutions Project' (USDA-NIFA Award 2014-70016-23028).

Technical Abstract: ARS researchers optimized the Ribonucleic-acid interference, RNAi, double stranded RNA trigger molecules by incorporating modified pyrimidines, to significantly increase hemipteran pest mortality. The three insect vectors threaten global food security and include: The Asian citrus psyllid (ACP), Diaphorina citri, the vector which transmits the bacterium Candidatus Liberibacter asiaticus, the most serious pathogen in citrus trees, called Huanglongbing (HLB); The Glassy-winged sharpshooter, Homalodisca vitripennis, that is a major vector spreading Xylella fastidiosa bacteria, that causes Pierce's Disease of grapevines, and is currently threatening olive production in Middle East; and The Silverleaf Whitefly, Bemisia tabaci, that is the vector for numerous viral pathogens, including Begomoviruses, Criniviruses, and others that infect over 100 different plants threatening production of all vegetables, beans, lenthil, tomato, peppers, etc. RNAi biopesticides degrade in the environment, are specific to the insect pest, thus do not harm beneficial insects, like bees. The significant increase in efficacy to kill the psyllid, leafhopper, and whitefly pests brings these RNAi biopesticides closer to development of products equal to chemical insecticides. Support in part from 'The Citrus Greening Solutions Project' (USDA-NIFA Award 2014-70016-23028).