The role of thermo-transient receptor potential channels in thermal acclimation in the red flour beetle, Tribolium castaneum

Insects have developed various strategies to overcome unfavorable temperature conditions.  Thermal acclimation is a physiological strategy to survive under variable temperature conditions. We investigated the role of three thermo-transient receptor potential channels (TRPs) - painless (TC007561), pyrexia (TC09731), and trpA1 (TC002449) - in heat-induced knockout and in thermal acclimation in the red flour beetle, Tribolium castaneum.  Using double stranded RNA-induced RNA interference (RNAi) technique, we tested the effect of these genes by measuring time to knockout at high temperature and recovery from knockout with and without a period of thermal acclimation. dsRNA injection of trpA1 (dstrpA1) significantly reduced the time to induce knockout compared to control both with and without thermal acclimation.  Without thermal acclimation, dsRNA injection of pyrexia significantly reduced recovery, while dsRNA injection of painless showed reduced recovery only after thermal acclimation.  We previously found that trpA1 is a thermosensor involved in negative thermotaxis at high temperatures.  Based on the current study, we suggest that trpA1 also protects the organism from knockout at high temperatures.  The two other TRPs we tested, pyrexia and painless, appear to protect the organism in the long term from negative effects of high temperature, but in different ways.