MAX3/CCD7 is a carotenoid cleavage dioxygenase required for the synthesis of a novel plant signaling molecule

Curr Biol. 2004 Jul 27;14(14):1232-8. doi: 10.1016/j.cub.2004.06.061.


Background: Plant development is exquisitely environmentally sensitive, with plant hormones acting as long-range signals that integrate developmental, genetic, and environmental inputs to regulate development. A good example of this is in the control of shoot branching, where wide variation in plant form can be generated in a single genotype in response to environmental and developmental cues.

Results: Here we present evidence for a novel plant signaling molecule involved in the regulation of shoot branching. We show that the MAX3 gene of Arabidopsis is required for the production of a graft-transmissible, highly active branch inhibitor that is distinct from any of the previously characterized branch-inhibiting hormones. Consistent with its proposed function in the synthesis of a novel signaling molecule, we show that MAX3 encodes a plastidic dioxygenase that can cleave multiple carotenoids.

Conclusions: We conclude that MAX3 is required for the synthesis of a novel carotenoid-derived long-range signal that regulates shoot branching.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Abscisic Acid / metabolism
  • Arabidopsis / enzymology*
  • Arabidopsis / growth & development
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Carotenoids / metabolism*
  • Chloroplasts / metabolism
  • Chromatography, High Pressure Liquid
  • DNA Primers
  • DNA, Complementary / genetics
  • Electrophoresis, Polyacrylamide Gel
  • Escherichia coli
  • Gene Expression Regulation, Plant*
  • Indoleacetic Acids / metabolism
  • Plant Shoots / growth & development*
  • Plant Shoots / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sequence Analysis, DNA
  • Signal Transduction / physiology*


  • Arabidopsis Proteins
  • DNA Primers
  • DNA, Complementary
  • Indoleacetic Acids
  • Carotenoids
  • Abscisic Acid