Cloning and Expression of Bursicon Gene of Myzus persicae (Sulzer)

Bursicon regulates the epidermal sclerosis and wing-spreading in insects. It plays a key role in epidermis hardening of insects after molting. The full-length sequences of the bursicon genes (burs-α and burs-β) of M. persicae (Sulzer) were obtained through cloning for this study, and named Mpburs-α (GenBank accession number:MF083566) and Mpburs-β (GenBank accession number:MF083567), respectively. Mpburs-α contained a 483 bp open reading frame (ORF) and was encoded 160 amino acid residues. Its molecular mass was predicted to be 17.59 kDa with a formula of C₇₅₉H₁₂₀₄N₂₁₀O₂₃₂S₁₉ and an isoelectric point of 7.96. Mpburs-β contained a 417 bp ORF and was encoded 138 amino acids. Its molecular mass to be 15.45 kDa with a formula of C₆₇₂H₁₀₇₂N₁₈₀O₂₁₂S₁₂ and an isoelectric point of 4.8. The phylogenetic tree analysis showed a relatively close genetic relationship of M. persicae with Acyrthosiphon pisum (Harris) and Diuraphis noxia (Mordvilko). The qRT-PCR results indicated that Mpburs-α and Mpburs-β expressed during the entire developmental stage of M. persicae and arrived at a peak expression level in the 1^st instar nymph. The expression levels of the two genes in the winged adult aphids were significantly higher than those in the wingless adult aphids suggesting an important role played by bursicon in the wing development for the insect. The finding might lead to further studies on the functions of bursicon in the molting epidermal ossification and wing formation of M. persicae.