Circadian clock-regulated phosphate transporter PHT4;1 plays an important role in Arabidopsis defense

Mol Plant. 2011 May;4(3):516-26. doi: 10.1093/mp/ssr016. Epub 2011 Mar 29.


The Arabidopsis accelerated cell death 6-1 (acd6-1) mutant shows constitutive defense, cell death, and extreme dwarf phenotypes. In a screen for acd6-1 suppressors, we identified a mutant that was disrupted by a T-DNA in the PHOSPHATE TRANSPORTER 4;1 (PHT4;1) gene. The suppressor mutant pht4;1-1 is dominant, expresses truncated PHT4;1 transcripts, and is more susceptible to virulent Pseudomonas syringae strains but not to several avirulent strains. Treatment with a salicylic acid (SA) agonist induced a similar level of resistance in Col-0 and pht4;1-1, suggesting that PHT4;1 acts upstream of the SA pathway. Genetic analysis further indicates that PHT4;1 contributes to SID2-dependent and -independent pathways. Transgenic expression of the DNA fragment containing the PHT4;1-1 region or the full-length PHT4;1 gene in wild-type conferred enhanced susceptibility to Pseudomonas infection. Interestingly, expression of PHT4;1 is regulated by the circadian clock. Together, these data suggest that the phosphate transporter PHT4;1 is critical for basal defense and also implicate a potential role of the circadian clock in regulating innate immunity of Arabidopsis.

Publication types

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

MeSH terms

  • Ankyrins / metabolism
  • Arabidopsis / drug effects
  • Arabidopsis / genetics
  • Arabidopsis / immunology*
  • Arabidopsis / microbiology
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Circadian Clocks* / drug effects
  • Circadian Clocks* / genetics
  • Circadian Clocks* / radiation effects
  • Gene Expression Regulation, Plant / drug effects
  • Gene Expression Regulation, Plant / radiation effects
  • Genes, Dominant / genetics
  • Light
  • Phenotype
  • Phosphate Transport Proteins / genetics
  • Phosphate Transport Proteins / metabolism*
  • Pseudomonas / drug effects
  • Pseudomonas / pathogenicity
  • Pseudomonas / radiation effects
  • Salicylic Acid / pharmacology
  • Suppression, Genetic / drug effects
  • Suppression, Genetic / radiation effects
  • Virulence / drug effects
  • Virulence / radiation effects


  • ACD6 protein, Arabidopsis
  • Ankyrins
  • Arabidopsis Proteins
  • PHT4;1 protein, Arabidopsis
  • Phosphate Transport Proteins
  • Salicylic Acid