RNAi in Tuta absoluta management: effects of injection and root delivery of dsRNAs

Genetically Modified Organism-Free RNA Interference: Exogenous Application of RNA Molecules in Plants

“…Interestingly, the introduced dsRNA was detected in 2.5-m tall 6-year-old Mexican limes (Citrus aurantifolia) even after 7 weeks post-single application (2-g dsRNA diluted in 15 L of water). After this proofof-concept report, several others followed, exhibiting significant degrees of pest management upon exogenous application of in vitro-transcribed/synthesized RNAs in plants: in Brassica oleracea, upon spraying of 59-PEG 21-nt siRNAs targeting the diamondback moth Plutella xylostella acetylcholine esterase genes AChE1 and AChE2; in tomato, upon application of dsRNA targeting the D. virgifera vacuolar ATPase (Ivashuta et al, 2015); in rice, upon root absorption of dsRNA targeting the brown planthopper Nilaparyata lugens P450 (Li et al, 2015); in maize, upon root absorption of dsRNA targeting the Ostrinia furnacalis KTI (Li et al, 2015); in potato (Solanum tuberosum), upon spraying of dsRNA targeting the Colorado potato beetle Leptinosa decemlineata actin; in tomato, upon petiole uptake of dsRNA targeting the tomato leafminer Tuta absoluta vacuolar ATPase (Camargo et al, 2016), and upon root absorption of dsRNA targeting T. absoluta ryanodine, acetylcholinesterase, and nicotinic acetylcholine alpha6 (Majidiani et al, 2019). In general, the orders Coleoptera, Lepidoptera, and Hemiptera include key pests of crops.…”

Prospects, challenges and current status of RNAi through insect feeding

“…Successful gene silencing through this methodology has been achieved in several species and some of them and the targeted genes are compiled in Table . Notably, many of the targeted genes, such as chitin synthase, α‐tubulin , and Vacuolar‐type H + ‐ATPase , are vital for the insects, and suppressing their translation can result in lethality . A plausible explanation for the inflated interest in this type of targets could be the enthusiasm in exploring this technique as an alternative pesticide method .…”

“…Mortalities up to 80% were observed in T. absoluta after they fed on plant leaves. These studies inferred that the plant phloem system is capable of delivering dsRNA to all tissues, which is advantageous to control insects that feed on plant tissues as well as sap fluid …”

“…Notably, many of the targeted genes, such as chitin synthase, -tubulin, and Vacuolar-type H + -ATPase, are vital for the insects, and suppressing their translation can result in lethality. 61,62 A plausible explanation for the inflated interest in this type of targets could be the enthusiasm in exploring this technique as an alternative pesticide method. 22 Nevertheless, RNAi strategies have also been used for the control of diseases in economically important insects such as honey bees and silkworms.…”

“…These studies inferred that the plant phloem system is capable of delivering dsRNA to all tissues, which is advantageous to control insects that feed on plant tissues as well as sap fluid. 62 In general, acceptable silencing efficiencies can be accomplished by the incorporation of synthetic dsRNA in insect diets. These effects are more tangible in RNAi susceptible species such as coleopterans, in which silencing rates approach ∼100% efficiency.…”