Identification and functional characterization of four transient receptor potential ankyrin 1 variants in Apolygus lucorum (Meyer-Dür).

As signal integrators that respond to various physical and chemical stimuli, transient receptor potential (TRP) channels fulfil critical functional roles in the sensory systems of both vertebrate and invertebrate organisms. Here, four variants of TRP ankyrin 1 (TRPA1) were identified and cloned from the green plant bug, Apolygus lucorum. Spatiotemporal expression profiling across development and in different adult tissues revealed that the highest relative-transcript levels occurred in first-instar nymphs and antennae, respectively. In Xenopus laevis-based functional assays, Apo. lucorum TRPA1-A (AlucTRPA1-A), AlucTRPA1-B and AlucTRPA1-C were activated by increasing the temperature from 20 to 40 °C with no significant desensitization observed after repeated temperature stimuli. The activation temperature of AlucTRPA1-A and AlucTRPA1-B was < 25 °C, whereas the activation temperature of AlucTRPA1-C was between 25 and 30 °C. Amongst the variants, only AlucTRPA1-A and AlucTRPA1-C were directly activated by high concentrations of allyl isothiocyanate, cinnamaldehyde and citronellal. Taken together, these results suggest that AlucTRPA1 variants may function in vivo as both thermal and chemical sensors, with the four variants potentially mediating different physiological functions. This study not only enriches our understanding of TRPA1 function in Hemiptera (Miridae), but also offers a foundation for developing new pest control strategies.
(© 2016 The Royal Entomological Society.)