Abstract

Molecular mechanisms of pattern formation in the plant embryo are not well understood. Recent molecular and cellular studies, in conjunction with earlier microsurgical, physiological, and genetic work, are now starting to define the outlines of a model where gradients of the signaling molecule auxin play a central role in embryo patterning. It is relatively clear how these gradients are established and interpreted, but how they are maintained is still unresolved. Here, we have studied the contributions of auxin biosynthesis, conjugation, and transport pathways to the maintenance of embryonic auxin gradients. Auxin homeostasis in the embryo was manipulated by region-specific conditional expression of indoleacetic acid-tryptophan monooxygenase or indoleacetic acid-lysine synthetase, bacterial enzymes for auxin biosynthesis or conjugation. Neither manipulation of auxin biosynthesis nor of auxin conjugation interfered with auxin gradients and patterning in the embryo. This result suggests a compensatory mechanism for buffering auxin gradients in the embryo. Chemical and genetic inhibition revealed that auxin transport activity, in particular that of the PIN-FORMED1 (PIN1) and PIN4 proteins, is a major factor in the maintenance of these gradients

Published in

Plant Cell
2005, Volume: 17, number: 9, pages: 2517-2526
Publisher: AMER SOC PLANT BIOLOGISTS

SLU Authors

• Ljung, Karin

  • Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences
    

• Sandberg, Göran

  • Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Forest Science


Publication identifier

DOI: https://doi.org/10.1105/tpc.105.034637

Permanent link to this page (URI)

https://res.slu.se/id/publ/7014