Efficacy and biosafety assessment of neuropeptide CAPA analogues against the peach-potato aphid (Myzus persicae))

Authors: SHI, YAN - Ghent University; NACHMAN, RONALD - Retired ARS Employee; GUI, SHUN-HUA - Ghent University; PIOT, NIELS - Ghent University; KACZMAREK, KRZYSZTOF - Technical University Of Lodz; ZABROCKI, JANUSZ - Technical University Of Lodz; DOW, JULIAN - University Of Glasgow; DAVIES, SHIREEN - University Of Glasgow; SMAGGHE, GUY - Ghent University

Submitted to: Insect Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/7/2021
Publication Date: 8/1/2021
Citation: Shi, Y., Nachman, R.J., Gui, S., Piot, N., Kaczmarek, K., Zabrocki, J., Dow, J.A., Davies, S.A., Smagghe, G. 2021. Efficacy and biosafety assessment of neuropeptide CAPA analogues against the peach-potato aphid (Myzus persicae)). Insect Science. 0:1-10. https://doi.org/10.1111/1744-7917.12951.
DOI: https://doi.org/10.1111/1744-7917.12951

Interpretive Summary: Because of problems with the development of resistance to conventional pesticides, there is a critical need for new concepts and alternative approaches in controlling insect pests. The basic premise of this research is that neuropeptides (short chains of amino acids) serve as potent hormone messengers in insects to regulate vital functions. Nevertheless, neuropeptides in and of themselves hold little promise as pest control agents because of susceptibility to being degraded in the target pest and inability to penetrate the outer shell of insects. New, selective control measures may be developed by designing stable mimics of these neuropeptide hormones that interact with the active site within the agricultural pest in such a way as to either inhibit or over-stimulate critical neuropeptide-regulated life functions. In this study, we describe the development of a new and practical ‘solid-phase’ method to incorporate into some neuropeptide molecules a stabilized component that mimics the 3-dimensional structure required by these hormones to regulate critical life processes. Because they are stabilized and not easily degraded, the resulting modified neuropeptides disrupt those critical life processes and can induce high mortality in treated pest insects. This new method is also applicable to biologically active peptides with medical applications. The methodology will facilitate the design and development of practical neuropeptide-like substances that can function as environmentally friendly and effective agents for the control of pest insect populations that are safe to beneficial insects like the honeybee.

Technical Abstract: Insect CAPA neuropeptides are known to influence ion and water balance by regulating the activity of the Malpighian tubules. In previous studies, the CAPA-PK analogue 1895 (2Abf-Suc-FGPRLamide) was reported to decrease aphid fitness when administered through micro-injection or via topical application. However, a further statistically significant decrease in the fitness of aphids and an increased mortality could not be established with pairwise combinations of 1895 with other CAPA analogues. In this study, we assessed the topical application of new combinations of 1895 with five CAPA-PVK analogues on the fitness of aphids. We found that 1895 and CAPA-PVK analogue 2315 (ASG-[ß3L]-VAFPRVamide) was statistically the most effective combination to control the peach potato aphid Myzus persicae nymphs via topical application, leading to 72% mortality. Additionally, the combination (1895+2315) was evaluated against a selection of beneficial insects, i.e. a pollinator (Bombus terrestris) and three natural enemies (Chrysoperla carnea, Adalia bipunctata and Nasonia vitripennis). We found no significant effects on weight increase, food intake and survival observed for the pollinator and the three representative natural enemies. These results could help to further develop, and optimize CAPA analogues as alternatives to broad spectrum and less environmentally friendly insecticides.