Nitrogen source interacts with ROP signalling in root hair tip-growth

Daria Bloch, Gabriele Monshausen, Meromit Singer, Simon Gilroy, Shaul Yalovsky

Research output: Contribution to journalArticlepeer-review

27 Scopus citations

Abstract

Root hairs elongate in a highly polarized manner known as tip growth. Overexpression of constitutively active Rho of Plant (ROP)/RAC GTPases mutants induces swelling of root hairs. Here, we demonstrate that Atrop11CA-induced swelling of root hairs depends on the composition of the growth medium. Depletion of ammonium allowed normal root hair elongation in Atrop11CA plants, induced the development of longer root hairs in wild-type plants and suppressed the effect of Atrop11CA expression on actin organization and reactive oxygen species distribution, whereas membrane localization of the protein was not affected. Ammonium at concentrations higher than 1 mM and the presence of nitrate were required for induction of swelling. Oscillations in wall and cytoplasmic pH are known to accompany tip growth in root hairs, and buffering of the growth medium decreased Atrop11CA-induced swelling. Fluorescence ratio imaging experiments revealed that in wild-type root hairs, the addition of NH4NO3 to the growth medium induced an increase in the amplitude of extracellular and intracellular pH oscillations and an overall decrease in cytoplasmic pH at the cell apex. Based on these results, we suggest a model in which ROP GTPases and nitrogen-dependent pH oscillations function in parallel pathways, creating a positive feedback loop during root hair growth.

Original languageEnglish (US)
Pages (from-to)76-88
Number of pages13
JournalPlant, Cell and Environment
Volume34
Issue number1
DOIs
StatePublished - Jan 1 2011

All Science Journal Classification (ASJC) codes

  • Physiology
  • Plant Science

Fingerprint Dive into the research topics of 'Nitrogen source interacts with ROP signalling in root hair tip-growth'. Together they form a unique fingerprint.

Cite this