NPR1-independent activation of immediate early salicylic acid-responsive genes in Arabidopsis

Carolina Uquillas, Ingrid Letelier, Francisca Blanco, Xavier Jordana, Loreto Holuigue

Research output: Contribution to journalArticlepeer-review

93 Citations (Scopus)


Salicylic acid (SA) is a key signal for the activation of defense genes in response to stress. The activation of late defense genes by SA, such as PR-1, involves the participation of the NPR1 protein. This protein acts as coactivator of the TGA factors that recognize as-1-like elements in the PR-1 promoter. Considering that functional as-1-like elements are also found in the promoter of SA- and auxin-responsive immediate early genes, we tested the hypothesis that NPR1 is also required for activation of these genes. The expression of the immediate early genes glutathione S-transferase (GST6) and glucosyltransferase (EIGT) was studied in npr1 mutant and wild-type Arabidopsis plants. In the npr1 mutant background, SA and 2,4-dichlorophenoxyacetic acid were unable to promote transcription of PR-1 but effectively stimulated the expression of GST6 and EIGT. Furthermore, increased binding of proteins to the GST6 as-1-like promoter element was detected in nuclear extracts from npr1 and wild-type plants after treatment with SA. In summary, these results indicate that activation of immediate early genes by SA proceeds through an NPR1-independent pathway. Therefore, we propose that activation by SA of immediate early and late genes occur by different mechanisms.

Original languageEnglish
Pages (from-to)34-42
Number of pages9
JournalMolecular Plant-Microbe Interactions
Issue number1
Publication statusPublished - Jan 2004

ASJC Scopus subject areas

  • Physiology
  • Agronomy and Crop Science


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