Physiological functions of a methuselah-like G protein coupled receptor in Lymantria dispar Linnaeus

Insect G protein coupled receptors (GPCRs) have been identified as a highly attractive target for new generation insecticides discovery due to their critical physiological functions. However, few insect GPCRs have been functionally characterized. Here, we cloned the full length of a methuselah-like GPCR gene (Ldmthll) from the Asian gypsy moth, Lymantria dispar. We then characterized the secondary and tertiary structures of Ldmthll. We also predicted the global structure of this insect GPCR protein which is composed of three major domains. RNA interference of Ldmthll resulted in a reduction of gypsy moths' resistance to deltamethrin and suppressed expression of downstream stress-associated genes, such as P450s, glutathione S transferases, and heat shock proteins. The function of Ldmthll was further investigated using transgenic lines of Drosophila melanogaster. Drosophila with overexpression of Ldmthll showed significantly longer lifespan than control flies. Taken together, our studies revealed that the physiological functions of Ldmthll in L. dispar are associated with longevity and resistance to insecticide stresses. Potentially, Ldmthll can be used as a target for new insecticide discovery in order to manage this notorious forest pest.