Assessment of neuropeptide binding sites and the impact of biostable kinin and CAP2b analogue treatment on aphid (Myzus persicae and Macrosiphum rosae) stress tolerance

Authors: ALFORD, LUCY - University Of Glasgow; MARLEY, RICHARD - University Of Glasgow; DORNAN, ANTHONY - University Of Glasgow; PIERRE, JEAN-SEBASTIEN - University Of Glasgow; DOW, JULIAN - University Of Glasgow; Nachman, Ronald; DAVIES, SHIREEN - University Of Glasgow

Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/27/2019
Publication Date: 6/15/2019
Citation: Alford, L., Marley, R., Dornan, A., Pierre, J., Dow, J., Nachman, R.J., Davies, S. 2019. Assessment of neuropeptide binding sites and the impact of biostable kinin and CAP2b analogue treatment on aphid (Myzus persicae and Macrosiphum rosae) stress tolerance. Pest Management Science. 75(6):1750-1759. https://doi.org/10.1002/ps.5372.
DOI: https://doi.org/10.1002/ps.5372

Interpretive Summary: Insect pests have developed resistance to several conventional pesticides, and new approaches are needed for pest management. Although neuropeptides (short chains of amino acids) serve as potent messengers in insects to regulate vital functions, the neuropeptides hold little promise as pest control agents because they can be degraded in the target pest. New, selective control agents may be developed by designing mimics of these neuropeptides that resist degradation and either inhibit or over-stimulate critical neuropeptide-regulated life functions. This work reports that mimics of the CAP2b neuropeptide class can reduce the tolerance to desiccation and cold stress that leads to significantly reduced lifespans in two species of aphids that represent major agricultural pests. Many mimic treatments lead to reduced lifespans, higher mortality, and repellency in pest insects. These results provide the basis for the development of practical neuropeptide-like substances that can effectively control pest insects in an environmentally friendly fashion.

Technical Abstract: BACKGROUND: Neuropeptides are regulators of critical life processes in insects and, due to their high specificity, represent potential targets in the development of greener insecticidal agents. Fundamental to this drive is understanding neuroendocrine pathways that control key physiological processes in pest insects and the screening of potential analogues. The current study investigated neuropeptide binding sites of kinin and CAPA in the pest aphids Myzus persicae and Macrosiphum rosae and the effect of biostable analogues on aphid fitness under conditions of desiccation, starvation and thermal (cold) stress. RESULTS: M. persicae and M. rosae displayed identical patterns of neuropeptide receptor mapping along the gut, with the gut musculature representing the main target for kinin and CAPA-1 neuropeptide action. Whilst kinin receptor binding was observed in the brain and VNC of M. persicae, the same was not observed in M. rosae. Furthermore, no CAPA-1 receptor binding was observed in the brain and VNC of either species. CAP2b analogues were most effective in reducing aphid fitness under conditions of desiccation and starvation stress, particularly analogues 1895 (2Abf-Suc-FGPRLa) and 2129 (2Abf-Suc-ATPRIa), which all expedited aphid mortality. All analogues, with the exception of 2139-Ac, were efficient at reducing aphid survival under cold stress conditions, although were equivalent in the strength of their effect. CONCLUSION: In demonstrating the effects of analogues belonging to the CAP2b neuropeptide family and key analogue structures that reduce aphid fitness under stress conditions, this research will feed into the development of second generation analogues and ultimately the development of neuropeptidomimetic-based aphicidal agents.