Molecular Characterization and Transcriptional Expression Analysis of ABC Transporter H Subfamily Genes in the Oriental Fruit Fly.

The oriental fruit fly, Bactrocera dorsalis Hendel (Diptera: Tephretidae), is a serious pest of fruits and vegetables and has developed high levels of insecticide resistance. ATP-binding cassette transporter genes (ABC transporters) are involved in mediating the energy-driven transport of many substances across membranes and are closely associated with development and insecticide detoxification. In this study, three ABC transporters in the H subfamily were identified, and the possible roles of these genes in B. dorsalis are discussed. Bioinformatics analysis revealed that those genes are conserved, typical of half-transporters. The expression profiles of BdABCH genes (BdABCHs) in the developmental stages, tissues, and following insecticide exposure, extreme temperature, warm- and cold-acclimated strain, starvation, and desiccation stress were determined by quantitative real-time PCR. Expression of BdABCHs can be detected in various tissues and in different developmental stages. They were most highly expressed in the hindgut and in newly emerged adults. The mRNA levels of BdABCHs in males (including most tissues and body segments) were higher than in females. The expression of BdABCH1 was significantly upregulated 3.8-fold in the cold-acclimated strain, and was significantly upregulated by 1.9-, 3.8- and 4.1-fold in the 0°C, starvation, and desiccation treatments, respectively. Treatment with malathion and avermectin at LD20 and LD30 concentrations produced no obvious changes in the levels of BdABCHs. BdABCHs may be involved in the transport of related hormones during eclosion, as well as water and inorganic salts. BdABCH1 also demonstrated that it is related to the ability to cope with adverse environments.