Functional analysis of the Arabidopsis PLDZ2 promoter reveals an evolutionarily conserved low-Pi-responsive transcriptional enhancer element

J Exp Bot. 2012 Mar;63(5):2189-202. doi: 10.1093/jxb/err446. Epub 2011 Dec 30.

Abstract

Plants have evolved a plethora of responses to cope with phosphate (Pi) deficiency, including the transcriptional activation of a large set of genes. Among Pi-responsive genes, the expression of the Arabidopsis phospholipase DZ2 (PLDZ2) is activated to participate in the degradation of phospholipids in roots in order to release Pi to support other cellular activities. A deletion analysis was performed to identify the regions determining the strength, tissue-specific expression, and Pi responsiveness of this regulatory region. This study also reports the identification and characterization of a transcriptional enhancer element that is present in the PLDZ2 promoter and able to confer Pi responsiveness to a minimal, inactive 35S promoter. This enhancer also shares the cytokinin and sucrose responsive properties observed for the intact PLDZ2 promoter. The EZ2 element contains two P1BS motifs, each of which is the DNA binding site of transcription factor PHR1. Mutation analysis showed that the P1BS motifs present in EZ2 are necessary but not sufficient for the enhancer function, revealing the importance of adjacent sequences. The structural organization of EZ2 is conserved in the orthologous genes of at least eight families of rosids, suggesting that architectural features such as the distance between the two P1BS motifs are also important for the regulatory properties of this enhancer element.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs
  • Amino Acid Sequence
  • Arabidopsis / cytology
  • Arabidopsis / enzymology
  • Arabidopsis / genetics*
  • Arabidopsis / physiology
  • Arabidopsis Proteins / genetics*
  • Arabidopsis Proteins / metabolism
  • DNA Mutational Analysis
  • Enhancer Elements, Genetic / genetics*
  • Gene Expression Regulation, Plant / genetics*
  • Molecular Sequence Data
  • Organ Specificity
  • Phosphates / deficiency*
  • Phospholipase D / genetics*
  • Phospholipase D / metabolism
  • Phospholipids / metabolism
  • Phylogeny
  • Plant Roots / cytology
  • Plant Roots / enzymology
  • Plant Roots / genetics
  • Plant Roots / physiology
  • Plants, Genetically Modified
  • Promoter Regions, Genetic / genetics
  • Sequence Alignment
  • Sequence Deletion

Substances

  • Arabidopsis Proteins
  • Phosphates
  • Phospholipids
  • Phospholipase D
  • phospholipase Dzeta2, Arabidopsis