LAUSR

BACKGROUND The cotton bollworm, Helicoverpa armigera, is a worldwide polyphagous pest, causing huge economic losses in vegetable, cotton, corn, etc. Due to the long-term exposure to Bacillus thuringiensis (Bt) toxins, evolution of resistance by this pest has been detected. As a conservative and effective neurotransmitter, dopamine plays an important role in insect growth and development. In this study, we investigated the regulatory functions of dopamine and its associated non-coding RNA in metamorphosis of Helicoverpa armigera. RESULTS Expression profiles indicated that dopamine and dopamine pathway genes were highly expressed during larval-pupal metamorphosis of H. armigera. RNA interference (RNAi) and pharmacological experiments have confirmed that tyrosine hydroxylase (TH), dopa decarboxylase (DDC), vesicular amine transporter (Vat), and dopamine receptor 2 (Dop2) were critical genes related to the development of H. armigera larvae to pupae. We also found that miR-14 and miR-2766 targeted the 3'untranslated region (3'UTR) to post-transcriptionally regulate HaTH function. Application of miR-2766 and miR-14 antagomirs significantly increased the levels of HaTH transcripts and proteins, while injections of miR-2766 and miR-14 agomirs not only suppressed the mRNA and protein levels of HaTH but also resulted in defective pupation of H. armigera. CONCLUSION These results suggest that dopamine deficiency inhibits the larval-pupal metamorphosis of H. armigera. Potentially, dopamine pathway genes and their miRNAs could be used as a novel target for H. armigera management. This article is protected by copyright. All rights reserved.