Arabidopsis AtSPL14, a plant-specific SBP-domain transcription factor, participates in plant development and sensitivity to fumonisin B1

Julie M. Stone, Xinwen Liang, Emily R. Nekl, Justin J. Stiers

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The recessive Arabidopsis thaliana fumonisin B1-resistant (fbr6) mutant was identified by its ability to survive in the presence of a programmed cell death (PCD)-inducing fungal toxin FB1. The fbr6 mutant also displays altered plant architecture in the absence of FB1, most notably elongated petioles and enhanced leaf margin serration. These phenotypes are a result of a T-DNA insertion in the SQUAMOSA promoter binding protein (SBP) domain gene, AtSPL14. AtSPL14 encodes a plant-specific protein with features characteristic of a transcriptional regulator, including a nuclear localization signal sequence, a plant-specific DNA binding domain (the SBP box), and a protein interaction motif (ankyrin repeats). A transiently expressed fusion of the AtSPL14 protein to green fluorescent protein is directed to the plant nucleus. DNA sequences immediately upstream of the translation start site direct expression of the β-glucuronidase reporter gene primarily in the vascular tissues, consistent with the phenotypes of the fbr6 mutant. AtSPL14 activates transcription in yeast, with a transactivation domain residing within the N-terminal region of the protein. Recombinant AtSPL14 protein binds A. thaliana genomic DNA in vitro in the absence of other proteins. These results indicate that FBR6/SPL14 functions as a transcriptional regulator that plays a role not only in sensitivity to FB1, but also in the development of normal plant architecture.

Original languageEnglish (US)
Pages (from-to)744-754
Number of pages11
JournalPlant Journal
Issue number5
StatePublished - Mar 1 2005



  • Arabidopsis thaliana
  • Fumonisin b1
  • Programmed cell death
  • SBP domain
  • Transcription

ASJC Scopus subject areas

  • Genetics
  • Plant Science
  • Cell Biology

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