Molecular Cloning and Expression Profiles of Thermosensitive TRP Genes inAgasicles hygrophila

Abstract

Simple Summary The increase of hot days with temperatures over 37 degrees C in southern China due to global warming has led to summer collapse of the alligator weed flea beetle, an introduced biological agent for the invasive alligator weed. To promote understanding of the beetle's adaption/tolerance to hot temperatures, we obtainedTRPA1,Painless, andPyrexia, three thermosensitive transient receptor potential channel genes from the beetle, and analyzed their expression patterns across different developmental stages and hot temperatures. Their constitutive expressions were dramatically different from each other and stage-specific. As temperature increased, their expressions in eggs elevated to their peak levels at 30 or 37.5 degrees C, and then fell back to their preferred temperature levels at temperatures > their peak temperatures. These results imply that (1) they may have different and stage-specific roles in perceiving high temperatures/chemicals and mediating the corresponding responses; and (2) their expressions may be decoupled from their activation. These findings lay a foundation for further understanding of the summer collapse of the beetle. Global warming has gradually reduced the control efficacy ofAgasicles hygrophilaagainst the invasive weedAlternanthera philoxeroides. To better understand the summer collapse ofA. hygrophilapopulations, we cloned the cDNA sequences of the high temperature-sensingTRPA1,Painless, andPyrexiafromA. hygrophila, and analyzed their temporal expressions and the impacts of high temperatures on their expression in eggs, the most vulnerable stage ofA. hygrophilato hot temperatures. All the three genes obtained had the signature domains of TRPA channels and were constitutively expressed in eggs, larvae (L1, L2, L3), pupae, and adults, butAhPainlesshad the highest expression, followed byAhPyrexia, andAhTRPA1. The lowest and highest expression stages were adult and pupae forAhTRPA1, egg and L3 forAhPainless, and pupae/adult and L2 forAhPyrexia. The expressions ofAhTRPA1,AhPainless, andAhPyrexiaremained low at the preferred temperature range of 25-28 degrees C, elevated to their peak levels at 37.5, 30, and 30 degrees C, respectively, then fell to their 25-28 degrees C levels (AhTRPA1,AhPainless) or a lower level (AhPyrexia) at one or more temperatures >30 or 37.5 degrees C. These results suggest that their temperature-sensing roles and importance may be different, stage-specific, and their expression may be decoupled from their activation.