A principal role for AtXTH18 in Arabidopsis thaliana root growth: A functional analysis using RNAi plants

Yasue Osato, Ryusuke Yokoyama, Kazuhiko Nishitani

Research output: Contribution to journalArticlepeer-review

68 Citations (Scopus)

Abstract

Rearrangement of cellulose microfibrils within cell-wall matrices is considered one of the most critical steps in the regulation of both the orientation and extent of cell expansion in plants. Xyloglucan endotransglucosylase/ hydrolases (XTHs) are a family of enzymes that mediate the construction and restructuring of load-bearing cross links among cellulose microfibrils. The Arabidopsis thaliana XTH genes AtXTH17, 18, 19, and 20 are phylogenetically closely related to one another and are preferentially expressed in the roots. However, they exhibit different expression profiles within the root and respond to hormonal signals differently. To investigate their functions in root growth, we examined phenotypes of loss-of-function mutants for these genes using T-DNA insertion lines and RNAi plants. These functional analyses disclosed a principal role for the AtXTH18 gene in primary root elongation. Of the four XTH genes, AtXTH18 exhibits the highest level of mRNA expression. We also determined auxin-signaling pathways for these genes using a mutant with a defect in the AXR2/IAA7 gene and found that the expression of AtXTH19 in the elongation/maturation region of the root is under the control of the AXR2/IAA7 signaling pathway.

Original languageEnglish
Pages (from-to)153-162
Number of pages10
JournalJournal of Plant Research
Volume119
Issue number2
DOIs
Publication statusPublished - 2006 Mar

Keywords

  • Auxin
  • Cell elongation
  • Cell wall
  • RNAi
  • Root
  • XTH

ASJC Scopus subject areas

  • Plant Science

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