Neuropeptide F from endocrine cells in Plutella xylostella midgut modulates feeding and synergizes Cry1Ac action.

ABSTRACT

With the wide cultivation of transgenic plants throughout the world and the rising risk of resistance to Bacillus thuringiensis crystal (Cry) toxins, it is essential to design an adaptive resistance management strategy for continued use. Neuropeptide F (NPF) of insects has proven to be valuable for the production of novel-type transgenic plants via its important role in the control of feeding behavior. In this study, the gene encoding NPF was cloned from the diamondback moth, Plutella xylostella, an important agricultural pest. Real-time quantitative reverse transcription-polymerase chain reaction and in situ hybridization showed a relatively high expression of P. xylostella-npf (P. x-npf) in endocrine cells of the midgut of fourth instar larvae, and it was found to participate in P. xylostella feeding behavior and Cry1Ac-induced feeding inhibition. Prokaryotic expression and purification provided structure unfolded P. x-npf from inclusion bodies for diet surface overlay bioassays and the results demonstrated a significant synergistic effect of P. x-npf on Cry1Ac toxicity by increasing intake of noxious food which contains Cry toxins, especially quick death at an early stage of feeding. Our findings provided a potential new way to efficiently control pests by increasing intake of lower dose Cry toxins and a novel hint for the complex Cry toxin mechanism.