These authors contributed equally to the work.
Juvenile hormone titre and related gene expression during the change of reproductive modes in the pea aphid
Article first published online: 12 OCT 2011
© 2011 The Authors. Insect Molecular Biology © 2011 The Royal Entomological Society
Insect Molecular Biology
Volume 21, Issue 1, pages 49–60, February 2012
How to Cite
Ishikawa, A., Ogawa, K., Gotoh, H., Walsh, T. K., Tagu, D., Brisson, J. A., Rispe, C., Jaubert-Possamai, S., Kanbe, T., Tsubota, T., Shiotsuki, T. and Miura, T. (2012), Juvenile hormone titre and related gene expression during the change of reproductive modes in the pea aphid. Insect Molecular Biology, 21: 49–60. doi: 10.1111/j.1365-2583.2011.01111.x
- Issue published online: 16 JAN 2012
- Article first published online: 12 OCT 2011
- juvenile hormone;
- juvenile hormone esterase;
- cyclical parthenogenesis
Most aphids show reproductive polyphenism, i.e. they alternate their reproductive modes from parthenogenesis to sexual reproduction in response to short photoperiods. Although juvenile hormone (JH) has been considered a likely candidate for regulating the transition from asexual to sexual reproduction after photoperiod sensing, there are few studies investigating the direct relationship between JH titres and the reproductive-mode change. In addition, the sequencing of the pea aphid genome has allowed identification of the genes involved in the JH pathway, which in turn allows us to examine their expression levels in relation to the reproductive-mode change. Using liquid chromatography-mass spectrometry in the pea aphid, JHIII titre was shown to be lower in aphids producing sexual morphs under short-day conditions than in aphids producing parthenogenetic morphs under long-day conditions. The expression levels of genes upstream and downstream of JH action were quantified by real-time quantitative reverse-transcription-PCR across the reproductive-mode change. The expression level of JH esterase, which is responsible for JH degradation, was significantly higher in aphids reared under short-day conditions. This suggests that the upregulation of the JH degradation pathway may be responsible for the lower JHIII titre in aphids exposed to short-days, leading to the production of sexual morphs.