Abstract

The bulk polar movement of the plant signaling molecule auxin through the stem is a longrecognized but poorly understood phenomenon. Here we show that the highly polar, high conductance polar auxin transport stream (PATS) is only part of a multimodal auxin transport network in the stem. The dynamics of auxin movement through stems are inconsistent with a single polar transport regime and instead suggest widespread low conductance, less polar auxin transport in the stem, which we term connective auxin transport (CAT). The bidirectional movement of auxin between the PATS and the surrounding tissues, mediated by CAT, can explain the complex auxin transport kinetics we observe. We show that the auxin efflux carriers PIN3, PIN4, and PIN7 are major contributors to this auxin transport connectivity and that their activity is important for communication between shoot apices in the regulation of shoot branching. We propose that the PATS provides a long-range, consolidated stream of information throughout the plant, while CAT acts locally, allowing tissues to modulate and be modulated by information in the PATS.

Published in

PLoS Biology
2016, Volume: 14, number: 4, article number: e1002446
Publisher: PUBLIC LIBRARY SCIENCE

SLU Authors

• Ljung, Karin

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

UKÄ Subject classification

Developmental Biology


Publication identifier

DOI: https://doi.org/10.1371/journal.pbio.1002446

Permanent link to this page (URI)

https://res.slu.se/id/publ/79231