Analysis of the Arabidopsis rsr4-1/pdx1-3 mutant reveals the critical function of the PDX1 protein family in metabolism, development, and vitamin B6 biosynthesis

Plant Cell. 2006 Jul;18(7):1722-35. doi: 10.1105/tpc.105.036269. Epub 2006 Jun 9.


Vitamin B6 represents a highly important group of compounds ubiquitous in all living organisms. It has been demonstrated to alleviate oxidative stress and in its phosphorylated form participates as a cofactor in >100 biochemical reactions. By means of a genetic approach, we have identified a novel mutant, rsr4-1 (for reduced sugar response), with aberrant root and leaf growth that requires supplementation of vitamin B6 for normal development. Cloning of the mutated gene revealed that rsr4-1 carries a point mutation in a member of the PDX1/SOR1/SNZ (for Pyridoxine biosynthesis protein 1/Singlet oxygen resistant 1/Snooze) family that leads to reduced vitamin B6 content. Consequently, metabolism is broadly altered, mainly affecting amino acid, raffinose, and shikimate contents and trichloroacetic acid cycle constituents. Yeast two-hybrid and pull-down analyses showed that Arabidopsis thaliana PDX1 proteins can form oligomers. Interestingly, the mutant form of PDX1 has severely reduced capability to oligomerize, potentially suggesting that oligomerization is important for function. In summary, our results demonstrate the critical function of the PDX1 protein family for metabolism, whole-plant development, and vitamin B6 biosynthesis in higher plants.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Arabidopsis / anatomy & histology
  • Arabidopsis / genetics
  • Arabidopsis / growth & development*
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / chemistry
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Carbon-Nitrogen Lyases
  • Chromosomes, Plant
  • Energy Metabolism
  • Flowers / anatomy & histology
  • Flowers / growth & development
  • Gene Expression Profiling
  • Genetic Complementation Test
  • Molecular Sequence Data
  • Nitrogenous Group Transferases / chemistry
  • Nitrogenous Group Transferases / genetics
  • Nitrogenous Group Transferases / metabolism*
  • Phenotype
  • Plant Leaves / anatomy & histology
  • Plant Leaves / growth & development
  • Plants, Genetically Modified
  • Point Mutation
  • Protein Structure, Quaternary
  • Pyridoxine / metabolism
  • Two-Hybrid System Techniques
  • Vitamin B 6 / biosynthesis*
  • Vitamin B Complex / biosynthesis*


  • Arabidopsis Proteins
  • Vitamin B Complex
  • Vitamin B 6
  • Nitrogenous Group Transferases
  • Carbon-Nitrogen Lyases
  • At2g38230 protein, Arabidopsis
  • Pyridoxine