Localized auxin biosynthesis and postembryonic root development in Arabidopsis

Hao Chen, Liming Xiong*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Auxin is a phytohormone essential for plant development. Due to the high redundancy in auxin biosynthesis, the role of auxin biosynthesis in embryogenesis and seedling development, vascular and flower development, shade avoidance and ethylene response were revealed only recently. We previously reported that a vitamin B6 biosynthesis mutant pdx1 exhibits a short-root phenotype with reduced meristematic zone and short mature cells. By reciprocal grafting, we now have found that the pdx1 short root is caused by a root locally generated signal. The mutant root tips are defective in callus induction and have reduced DR5::GUS activity, but maintain relatively normal auxin response. Genetic analysis indicates that pdx1 mutant could suppress the root hair and root growth phenotypes of the auxin overproduction mutant yucca on medium supplemented with tryptophan (Trp), suggesting that the conversion from Trp to auxin is impaired in pdx1 roots. Here we present data showing that pdx1 mutant is more tolerant to 5-methyl anthranilate, an analogue of the Trp biosynthetic intermediate anthranilate, demonstrating that pdx1 is also defective in the conversion from anthranilate to auxin precursor tryptophan. Our data suggest that locally synthesized auxin may play an important role in the postembryonic root growth.

Original languageEnglish (US)
Pages (from-to)752-754
Number of pages3
JournalPlant Signaling and Behavior
Volume4
Issue number8
DOIs
StatePublished - Nov 26 2009

Keywords

  • Auxin synthesis
  • PDX1
  • PLP
  • Root

ASJC Scopus subject areas

  • Plant Science

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