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. 10(9). Article 1782. https://doi.org/10.3390/plants10091782.
DOI: https://doi.org/10.3390/plants10091782

Interpretive Summary: ARS researchers developed a safer, more specific biopesticides to control insect pests. This includes: the Asian citrus psyllid (ACP), Diaphorina citri,which transmits the bacterial pathogen that kills citrus fruit trees call Huanglongbing; the Glassy-winged sharpshooter leafhopper, that transmit a bacterial pathogen that kills grapevines (Pierce's Disease), nut trees, and woody ornamentals, and The Whiteflies that transmit a large number of plant-infecting viruses, like Begomoviruses. These three insect vectors of crop pathogens threaten global food security. Demonstrated was the significant improved insect mortality, when incorporating modified nucleotides in the Ribonucleic acid interference, RNAi, molecules. RNAi biopesticides are safer because they degrade rapidly, are specific to the insect pest, thus do not harm beneficial insects, like bees. The significant increase in efficacy to reduce these pests, psyllids, leafhoppers, and whiteflies brings these RNAi biopesticides closer in activity to commercial chemical insecticides.

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).