An auxin gradient and maximum in the Arabidopsis root apex shown by high-resolution cell-specific analysis of IAA distribution and synthesis.

Journal Article (Journal Article)

Local concentration gradients of the plant growth regulator auxin (indole-3-acetic acid [IAA]) are thought to instruct the positioning of organ primordia and stem cell niches and to direct cell division, expansion, and differentiation. High-resolution measurements of endogenous IAA concentrations in support of the gradient hypothesis are required to substantiate this hypothesis. Here, we introduce fluorescence-activated cell sorting of green fluorescent protein-marked cell types combined with highly sensitive mass spectrometry methods as a novel means for analyses of IAA distribution and metabolism at cellular resolution. Our results reveal the presence of IAA concentration gradients within the Arabidopsis thaliana root tip with a distinct maximum in the organizing quiescent center of the root apex. We also demonstrate that the root apex provides an important source of IAA and that cells of all types display a high synthesis capacity, suggesting a substantial contribution of local biosynthesis to auxin homeostasis in the root tip. Our results indicate that local biosynthesis and polar transport combine to produce auxin gradients and maxima in the root tip.

Full Text

Duke Authors

Cited Authors

  • Petersson, SV; Johansson, AI; Kowalczyk, M; Makoveychuk, A; Wang, JY; Moritz, T; Grebe, M; Benfey, PN; Sandberg, G; Ljung, K

Published Date

  • June 2009

Published In

Volume / Issue

  • 21 / 6

Start / End Page

  • 1659 - 1668

PubMed ID

  • 19491238

Pubmed Central ID

  • PMC2714926

Electronic International Standard Serial Number (EISSN)

  • 1532-298X

International Standard Serial Number (ISSN)

  • 1040-4651

Digital Object Identifier (DOI)

  • 10.1105/tpc.109.066480


  • eng