title: Deciphering the Function of Octopaminergic Signaling on Wing Polyphenism of the Pea AphidAcyrthosiphon pisum.
abstract: Aphids exhibit wing polyphenism (winged or wingless) for adaption to predictable or temporally heterogeneous environmental changes; however, the underlying mechanism is still unclear. This morphological change could be stimulated by high aphid density, which in turn could affect octopaminergic signaling in aphids. Octopamine is a neurotransmitter synthesized in insects that can modify their physiological metabolism, locomotion, and other behaviors. We designed experiments to determine whether octopamine functions in wing formation of the pea aphid,Acyrthosiphon pisum(Harris). We determined gene expression of tyramine β-hydroxylase (TβH), a key enzyme in octopamine synthesis at different developmental stages, in different body parts, and in different densities of aphids. We also usedTβHRNAi, octopamine receptor agonists (octopamine and synephrine), and an antagonist (mianserin) to modify octopaminergic signaling. We found that transcription ofTβHwas related to aphid density, which affected the proportion of winged offspring. By manually modifying the mother's octopaminergic signaling,TβHexpression was suppressed, and TβH (enzyme) activity decreased. The proportion of winged offspring was also affected. Our results showed that octopamine could be a link in the wing determination system, as well as environmental stimulation. The RNAi results showed that the decrease ofTβHexpression increased aphid's reproduction; however, the decrease ofTβHexpression declined the numbers of winged-offspring producers, but did not affect the proportion of winged nymphs produced by the winged-offspring producer. In conclusion, the decline in the proportion of winged daughters in the next generation was caused by the decline of winged nymph producers.
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas, and Key Laboratory of Integrated Pest Management on the Loess Plateau of Ministry of Agriculture, Northwest A&F University Yangling, China.
authors.forename: Xing-Xing
authors.initials: XX
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas, and Key Laboratory of Integrated Pest Management on the Loess Plateau of Ministry of Agriculture, Northwest A&F University Yangling, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas, and Key Laboratory of Integrated Pest Management on the Loess Plateau of Ministry of Agriculture, Northwest A&F University Yangling, China.
authors.forename: Zhan-Feng
authors.initials: ZF
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas, and Key Laboratory of Integrated Pest Management on the Loess Plateau of Ministry of Agriculture, Northwest A&F University Yangling, China.
authors.forename: Hong-Gang
authors.initials: HG
authors.lastname: Tian
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas, and Key Laboratory of Integrated Pest Management on the Loess Plateau of Ministry of Agriculture, Northwest A&F University Yangling, China.
authors.forename: Tong-Xian
authors.initials: TX
authors.lastname: Liu
keywords: RNA interference; alate; apterae; neurotransmitter; tyramine β-hydroxylase; winged and wingless