MAX3/CCD7 Is a Carotenoid Cleavage Dioxygenase Required for the Synthesis of a Novel Plant Signaling Molecule

Here we present evidence for a novel plant signaling molecule involved in the regulation of shoot branching

Jonathan Booker; Michele Auldridge; Sarah Wills; Donald McCarty; Harry Klee; Ottoline Leyser


Scholarcy highlights

  • A unique feature of plant development is the ability to alter body plan in response to environmental conditions
  • 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
  • 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
  • We conclude that MAX3 is required for the synthesis of a novel carotenoid-derived long-range signal that regulates shoot branching
  • We conclude that MAX3 is required for the synthesis of a novel, graft-transmissible inhibitor of shoot branching
  • Cells were grown in LB with 0.1% glucose at 30°C for varying amounts of time depending on the extraction procedure
  • The identity of this compound remains to be determined, but we have shown that it is likely to be a carotenoid derivative, it is probably produced in small quantities, it is highly active, and it is translocated though the plant and modifies growth in distant organs, indicating that it can be classified as a novel plant hormone
  • ]. For apocarotenoid analysis, cell cultures of the phytoene, ζ-carotene, lycopene, and zeaxanthin-accumulating strains were grown for no more than 12 hr and were extracted by the addition of an equal volume of hexane

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