Shoot-derived auxin is essential for early lateral root emergence in Arabidopsis seedlings

  • Bhalerao R
  • Eklöf J
  • Ljung K
 et al. 
  • 170


    Mendeley users who have this article in their library.
  • 296


    Citations of this article.


Lateral root formation is profoundly affected by auxins. Here we present data which indicate that light influences the formation of indole-3-acetic acid (IAA) in germinating Arabidopsis seedlings. IAA transported from the developing leaves to the root system is detectable as a short-lived pulse in the roots and is required for the emergence of the lateral root primordia (LRP) during early seedling development. LRP emergence is inhibited by the removal of apical tissues prior to detection of the IAA pulse in the root, but this treatment has minimal effects on LRP initiation. Our results identify the first developing true leaves as the most likely source for the IAA required for the first emergence of the LRP, as removal of cotyledons has only a minor effect on LRP emergence in contrast to removal of the leaves. A basipetal IAA concentration gradient with high levels of IAA in the root tip appears to control LRP initiation, in contrast to their emergence. A significant increase in the ability of the root system to synthesize IAA is observed 10 days after germination, and this in turn is reflected in the reduced dependence of the lateral root emergence on aerial tissue-derived auxin at this stage. We propose a model for lateral root formation during early seedling development that can be divided into two phases: (i) an LRP initiation phase dependent on a root tip-localized IAA source, and (ii) an LRP emergence phase dependent on leaf-derived IAA up to 10 days after germination.

Author-supplied keywords

  • Arabidopsis thaliana
  • Auxin
  • IAA
  • Lateral root

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document


  • Rishikesh P. Bhalerao

  • Jan Eklöf

  • Karin Ljung

  • Alan Marchant

  • Malcolm Bennett

  • Göran Sandberg

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free