Molecular analysis of the LATERAL SUPPRESSOR gene in Arabidopsis reveals a conserved control mechanism for axillary meristem formation

  1. Thomas Greb,
  2. Oliver Clarenz,
  3. Elisabeth Schäfer,
  4. Dörte Müller,
  5. Rubén Herrero,
  6. Gregor Schmitz, and
  7. Klaus Theres1
  1. Max Planck Institute for Plant Breeding Research, D-50829 Cologne, Germany

Abstract

In seed plants, shoot branching is initiated by the formation of new meristems in the axils of leaves, which subsequently develop into new axes of growth. This study describes the genetic control of axillary meristem formation by the LATERAL SUPPRESSOR (LAS) gene in Arabidopsis thaliana. las mutants show a novel phenotype that is characterized by the inability to form lateral shoots during vegetative development. The analysis shows that axillary meristem formation is differently regulated during different phases of development. During reproductive development, axillary meristems initiate in close proximity to the shoot apical meristem and do not require LAS function. In contrast, during the vegetative phase, axillary meristems initiate at a distance to the SAM and requireLAS function. This control mechanism is conserved between the distantly related species tomato and Arabidopsis. Monitoring the patterns of LAS and SHOOT MERISTEMLESS transcript accumulation allowed us to identify early steps in the development of leaf axil identity, which seem to be a prerequisite for axillary meristem initiation. Other regulators of shoot branching, likeREVOLUTA and AUXIN RESISTANT 1, act downstream ofLAS. The results are discussed in the context of the “detached meristem” and the “de novo formation” concepts of axillary meristem formation.

Keywords

Footnotes

  • 1 Corresponding author.

  • E-MAIL theres{at}mpiz-koeln.mpg.de; FAX 49-221-5062 413.

  • Article and publication are at http://www.genesdev.org/cgi/doi/10.1101/gad.260703.

    • Received January 22, 2003.
    • Accepted March 14, 2003.
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