Catalyzing systemic movement of inward rectifier potassium channel inhibitors for antifeedant activity against the cotton aphid, Aphis gossypii (Glover). Issue 1 (3rd October 2022)

• Record Type: Journal Article
• Authors: O'Hara, Flinn M; Liu, Zhijun; Davis, Jeffrey A; Swale, Daniel R
• Is Part Of: Pest management science. Volume 79:Issue 1(2023)
• Page Start: 194
• Page End: 205
• Publication Date: 2022-10-03
• Subjects: insecticide -- systemic -- antifeedant -- salivary gland -- solubility enhancement; Pests -- Control -- Periodicals; Pesticides -- Periodicals; 632.9
• DOI: 10.1002/ps.7188
• Languages: English
• ISSNs: 1526-498X

Abstract

Abstract: Background: The cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), is a destructive agricultural pest, capable of photosynthate removal and plant virus transmission. Therefore, we aimed to test the antifeedant properties of small‐molecule inhibitors of inward rectifier potassium (Kir) channels expressed in insect salivary glands and develop an approach for enabling systemic movement of lipophilic Kir inhibitors. Results: Two Kir channel inhibitors, VU041 and VU730, reduced the secretory activity of the aphid salivary glands by 3.3‐fold and foliar applications of VU041 and VU730 significantly ( P < 0.05) increased the time to first probe, total probe duration, and nearly eliminated phloem salivation and ingestion. Next, we aimed to facilitate systemic movement of VU041 and VU730 through evaluation of a novel natural product based solubilizer containing rubusoside that was isolated from Chinese sweet leaf ( Rubus suavissimus ) plants. A single lower leaf was treated with Kir inhibitor soluble liquid (KI‐SL) and systemic movement throughout the plant was verified via toxicity bioassays and changes to feeding behavior through the electrical penetration graph (EPG) technique. EPG data indicate KI‐SL significantly reduced ability to reach E1 (phloem salivation) and E2 (phloem ingestion) waveforms and altered plant probing behavior when compared to the untreated control. High‐performance liquid chromatography (HPLC) analysis indicated the presence of VU041 and VU730 in the upper leaf tissue of these plants. Together, these data provide strong support that incorporation of rubusoside with Kir inhibitors enhanced translaminar and translocation movement through the plant tissue. Conclusion: These data further support hemipteran Kir channels as a target to prevent feeding and induce toxicity. Further, these studies highlight a novel delivery approach for generating plant systemic activity of lipophilic insecticides. © 2022 Society of Chemical Industry. Abstract : Pharmacological inhibitors of inward rectifier potassium (Kir) ion channels reduced the secretory activity of the Aphis gossypii salivary gland and altered feeding behavior. Rubusoside was used to enable systemic movement of Kir inhibitors through the plant and reduced xylem and phloem ingestion was documented.