Elucidation of Insect Olfaction in the Pea Aphid, Acyrthosiphon pisum
Lead Research Organisation:
University of Nottingham
Department Name: Sch of Chemistry
Abstract
Aphids (Homoptera: Aphididae) are the major pests of arable and horticultural crops in Western and Northern Europe, causing direct damage through their feeding or indirectly through the transmission of plant pathogens eg Barley Yellow Dwarf Virus (BYDV). The sex pheromone components of the pea aphid, Acyrthosiphon pisum, comprise of a mixture of two iridoids (cyclopentanoids), (4aS,7S,7aR)-nepetalactone and (1R,4aS,7S,7aR)-nepetalactol that are emitted by females during the sexual phase of their life cycle. Male aphids are attracted to the sex pheromone and respond to the ratio of the pheromone components in a species-specific manner. Their enantiomers, (4aR,7R,7aS)-nepetalactone and (1S,4aR,7R,7aS)-nepetalactol are not naturally-occurring and do not possess biological activity although they have the same physical and chemical properties as the sex pheromone components and only differ in their three-dimensional structure as mirror images. A. pisum can serve as a tractable model system for investigation of the mechanisms underlying molecular recognition of odorants in animals because of (i) already identified odorants, in particular sex pheromone components described above Nat. Prod. Rep. 2013, 30:1277-1283 (ii) recent advances in the annotation of the pea aphid genome, specifically olfactory proteins that can recognise and discriminate between different odorants (PLoS Biol 2010, 8: e1000313; Insect Mol. Biol. 2010, 19:113-122 and (iii) readily accessible olfactory organs, i.e., aphid antennae. Despite the crucial role that olfaction plays in aphid biology, it has not been possible to elucidate and discriminate unequivocally between two hypotheses underlying the molecular recognition mechanisms underpinning olfactory perception at the peripheral level, ie. (i) odorants directly activate odorant receptors (ORs) (Hypothesis A), and (ii) ORs are activated by odorant-binding protein (OBP)-odorant complexes (Hypothesis B). This project seeks to use a multi-disciplinary approach including molecular biology, electrophysiology and analytical/synthetic organic chemistry to test the two hypotheses showing whether or not there is an essential role for OBPs in determining specific molecular recognition of odorants. Male-antenna specific OR and OBP genes in the A. pisum genome will be identified and quantified using real time RT-qPCR. Male-specific OR genes will be functionally expressed in Xenopus oocytes for functional characterisation with a two electrode voltage clamp technique (PLoS One 2013, 8:e62098). The non-natural enantiomers of the sex pheromone components will be synthesized and used to explore enantiomer discrimination at the OR level. The specificity and response kinetics of male ORs to aphid sex pheromone components and their enantiomers will be measured with and without OBPs. The ability of male-antenna specific OBPs to discriminate enantiomers will be measured using an established high-throughput ESI-MS assay to be done by a collaborating lab (Dr Ales Svatos, Max-Planck Institute for Chemical Ecology, Jena.
People |
ORCID iD |
Neil Oldham (Primary Supervisor) |
Publications
Sims C
(2023)
Pea aphid odorant-binding protein ApisOBP6 discriminates between aphid sex pheromone components, aphid alarm pheromone and a host plant volatile.
in Insect biochemistry and molecular biology
Sims C
(2022)
Enantiomeric Discrimination in Insects: The Role of OBPs and ORs.
in Insects
Sims C
(2023)
Computational investigation of aphid odorant receptor structure and binding function.
in Journal of biomolecular structure & dynamics
Studentship Projects
Project Reference | Relationship | Related To | Start | End | Student Name |
---|---|---|---|---|---|
BB/M008770/1 | 30/09/2015 | 31/03/2024 | |||
1804053 | Studentship | BB/M008770/1 | 30/09/2016 | 28/10/2020 |
Description | This project aims to look at the mechanism of molecular recognition of these components within aphids, using A. pisum as a model. This involves the study of the aphid's olfactory systems, including the odorant-receptors (ORs) and odorant-binding proteins (OBPs), which are small, soluble proteins found in the antennae of insects. In the project so far, the sex pheromone components and respective enantiomers have been synthesised as described in previous work (Bioorganic Med. Chem., 1996, 4, 351-361). Cell lines (E. coli BL21) expressing OBPs from A. pisum have been generated, and OBPs 3,6,7 and 9 produced on a large scale. |
Exploitation Route | Findings from this study have a wide range of applications. Novel protein-ligand binding techniques can be utilised in all areas of biological and medicinal chemistry including agriculture and pharmaceuticals. A more in-depth understanding of the molecular mechanisms of olfaction in insects could help design new pest control, such as attractants and repellents, that can be used in integrated pest management (IPM) strategies, and subsequently significantly reduce the use of pesticides on crops. |
Sectors | Agriculture Food and Drink Chemicals |
Description | PhD: Elucidation of Insect Olfaction in the Pea Aphid, Acyrthosiphon pisum |
Organisation | University of Nottingham |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Principal PhD supervisor, co-supervisor |
Collaborator Contribution | Co-supervisor |
Impact | Work in progress |
Start Year | 2016 |
Description | Attendence at outreach/speed networking event |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Schools |
Results and Impact | Attendence at science and roller derby event. A speed networking event was conducted where we spoke to young girls aged 14-19 about careers in STEM and our individual work. |
Year(s) Of Engagement Activity | 2019 |
Description | Cafe Scientifique Talk |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Public/other audiences |
Results and Impact | A Cafe Scientifique talk on how insects smell was given at a local event. This involved presenting to the general public, including an interactive activity with different smelling compounds. |
Year(s) Of Engagement Activity | 2017 |
Description | Careers talk at university |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Undergraduate students |
Results and Impact | A talk on being a PhD student and how to get into a PhD to undergraduate and postgraduate students at my alumni university, Keele University. |
Year(s) Of Engagement Activity | 2019 |
Description | STEMRoller 2020 |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Schools |
Results and Impact | Participation in event centered around encouraging young female and non-binary students into science. The event involved speed networking with STEM professionals, and a game of roller derby played entirley by STEM professionals. In addition to my pariticipation, I also secured a £2000 Royal Society of Chemistry outreach grant for this event. |
Year(s) Of Engagement Activity | 2020 |
Description | Short talk at science festival |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Public/other audiences |
Results and Impact | A short poem about the general applications of this work was delivered as part of a science festival at Rothamsted Research |
Year(s) Of Engagement Activity | 2018 |
Description | Soapbox Science Presentation |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Public/other audiences |
Results and Impact | Short presentation in a local shopping centre about insect olfaction, desgined to engage with the general public. |
Year(s) Of Engagement Activity | 2019 |
URL | https://mksoapboxscience.wordpress.com/2019/06/26/why-science-outreach-matters-meet-cassie-sims/ |