Aldehyde dehydrogenase 3 converts farnesal into farnesoic acid in the corpora allata of mosquitoes

Insect Biochem Mol Biol. 2013 Aug;43(8):675-82. doi: 10.1016/j.ibmb.2013.04.002. Epub 2013 Apr 29.


The juvenile hormones (JHs) play a central role in insect reproduction, development and behavior. Interrupting JH biosynthesis has long been considered a promising strategy for the development of target-specific insecticides. Using a combination of RNAi, in vivo and in vitro studies we characterized the last unknown biosynthetic enzyme of the JH pathway, a fatty aldehyde dehydrogenase (AaALDH3) that oxidizes farnesal into farnesoic acid (FA) in the corpora allata (CA) of mosquitoes. The AaALDH3 is structurally and functionally a NAD(+)-dependent class 3 ALDH showing tissue- and developmental-stage-specific splice variants. Members of the ALDH3 family play critical roles in the development of cancer and Sjögren-Larsson syndrome in humans, but have not been studies in groups other than mammals. Using a newly developed assay utilizing fluorescent tags, we demonstrated that AaALDH3 activity, as well as the concentrations of farnesol, farnesal and FA were different in CA of sugar and blood-fed females. In CA of blood-fed females the low catalytic activity of AaALDH3 limited the flux of precursors and caused a remarkable increase in the pool of farnesal with a decrease in FA and JH synthesis. The accumulation of the potentially toxic farnesal stimulated the activity of a reductase that converted farnesal back into farnesol, resulting in farnesol leaking out of the CA. Our studies indicated AaALDH3 plays a key role in the regulation of JH synthesis in blood-fed females and mosquitoes seem to have developed a "trade-off" system to balance the key role of farnesal as a JH precursor with its potential toxicity.

Keywords: Aedes aegypti; Aldehyde dehydrogenase 3; Aldo-keto reductase; Corpora allata; Farnesal; Juvenile hormone; Mosquito; RNAi.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Aedes / enzymology*
  • Age Factors
  • Aldehyde Dehydrogenase / metabolism*
  • Aldehyde Oxidoreductases / metabolism
  • Animals
  • Corpora Allata / enzymology*
  • Farnesol / analogs & derivatives*
  • Farnesol / metabolism
  • Fatty Acids, Unsaturated / metabolism*
  • Female
  • Homeostasis
  • Juvenile Hormones / biosynthesis
  • RNA, Messenger / metabolism


  • Fatty Acids, Unsaturated
  • Juvenile Hormones
  • RNA, Messenger
  • Farnesol
  • farnesoic acid
  • Aldehyde Oxidoreductases
  • farnesal dehydrogenase
  • Aldehyde Dehydrogenase
  • farnesal