Molecular cloning and characterization of a growth-blocking peptide from the honeybee Apis mellifera

Abstract

• Bee ( Apis mellifera, A. cerana, Bombus terrestris, and B. ignitus ) growth-blocking peptides (GBPs) were cloned. • AmGBP was expressed at the larval stage. • RNAi-treatment of AmGBP affected larval development and larval-pupal transformation. Growth-blocking peptides (GBPs) are insect cytokines that have been characterized from several species. However, molecular studies on hymenopteran GBPs remain limited. In this study, we cloned four GBP cDNAs of honeybees and bumblebees and compared their sequences with those of other insect GBPs. Sequence analysis revealed that GBP from bees conserves a mature peptide with 21–25 amino acids, including two conserved cysteine residues. During Apis mellifera development, AmGBP was expressed at the larval stage but not at the pupal stage. AmGBP transcript reduction by RNAi affected larval growth and reduced body weight gain. AmGBP RNAi-treated larvae on day 4 were arrested to the larval stage and finally died. Our data suggested that AmGBP plays an essential role in larval growth and acts as a growth factor at the larval stage of A. mellifera .