Molecules to Morphology: Developing an Understanding of Plant Evolution Through Time
Cooke, Todd J. , Cohen, Jerry D. .
The evolution of auxin action in land plants.
The hormone auxin (indole-3-acetic acid) regulates many developmental phenomena in flowering plants, including embryogenesis, apical dominance, phyllotaxis, tropisms, root initiation, and wounding responses. In flowering plants, the action of auxin depends on sophisticated biochemical and physiological mechanisms operating to control effective auxin levels and polar auxin transport. This talk focuses on the evolution of those mechanisms of auxin action and their developmental consequences in contemporary lineages of land plants and their closest algal relatives, the Charales. For example, it appears that free auxin levels in different lineages are primarily controlled by different metabolic strategies, viz., biosynthesis/efflux in Charales, biosynthesis/degradation in liverworts and mosses, and conjugation/hydrolysis in other land plants. The Charales have evolved a simple form of auxin transport, whereas bryophyte sporophytes exhibit several different mechanisms of intercellular auxin transport, which display certain, but not all, characteristics of the polar auxin transport occurring in vascular plant sporophytes. These findings inform our discussion about the roles of auxin action in the origins of the embryo, different body plans, spatial organization of plant organs, and other important developmental processes in the land plant lineage.
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1 - University of Maryland, Cell Biology and Molecular Genetics, College Park, Maryland, 20742, USA
2 - University of Minnesota, Horticultural Science, 305 Alderman Hall, 1970 Folwell Avenue, Saint Paul, MN, 55108, USA
Presentation Type: Symposium or Colloquium Presentation
Location: Stevens 5/Hilton
Date: Wednesday, July 11th, 2007
Time: 3:00 PM