Reception and coding of pheromone signals in insects
In insects, the molecular signal recognition in the antenna and primary processing events in the antennal lobe form the bases for olfactory coding and odorant-driven behaviours. Based on advanced knowledge on the pheromone system of Heliothis virescens the proposed project aims on elucidating the early events in pheromone recognition and coding. In addition, the project intends to illuminate how co-existing odorants interfere with these primary processes and affect pheromone-driven behaviour. In more detail, we will explore the contribution of “Sensory Neuron Membrane Proteins” (SNMPs) in the detection of the major sex pheromone component by “reconstituting” the SNMP1/HR13 receptor system in cell culture and by performing calcium imaging of the pheromone binding protein (PBP)-mediated pheromone response. The proposed molecular interaction of PBP and SNMP1 will be investigated by analyzing binding of PBP to SNMP1-expressing cells employing nanosome preparations in surface plasmon resonance spectroscopy and labelled PBP. The molecular events underlying the detection of a minor sex pheromone component will be explored by identifying the PBP involved and its interplay with a specific receptor and SNMP1. Since certain odorants inhibit the response of the pheromone-specific sensory neurons, we will assess if receptors and SNMP1 are molecular targets of the peripheral inhibition. The question, how co-existing inhibitory plant volatiles in the environment affect pheromone-driven behaviour will be scrutinized in wind-tunnel experiments. Because specific pheromone-driven behaviour is sensitive to changes in the ratio of major and minor components in the pheromone blend, we will investigate how optimal or disturbed mix ratios are represented in the antennal lobe by in vivo imaging of blend-induced activity patterns.