Arabidopsis Bax inhibitor-1 functions as an attenuator of biotic and abiotic types of cell death

Plant J. 2006 Mar;45(6):884-94. doi: 10.1111/j.1365-313X.2006.02654.x.


Programmed cell death (PCD) is a common process in eukaryotes during development and in response to pathogens and stress signals. Bax inihibitor-1 (BI-1) is proposed to be a cell death suppressor that is conserved in both animals and plants, but the physiological importance of BI-1 and the impact of its loss of function in plants are still unclear. In this study, we identified and characterized two independent Arabidopsis mutants with a T-DNA insertion in the AtBI1 gene. The phenotype of atbi1-1 and atbi1-2, with a C-terminal missense mutation and a gene knockout, respectively, was indistinguishable from wild-type plants under normal growth conditions. However, these two mutants exhibit accelerated progression of cell death upon infiltration of leaf tissues with a PCD-inducing fungal toxin fumonisin B1 (FB1) and increased sensitivity to heat shock-induced cell death. Under these conditions, expression of AtBI1 mRNA was up-regulated in wild-type leaves prior to the activation of cell death, suggesting that increase of AtBI1 expression is important for basal suppression of cell death progression. Over-expression of AtBI1 transgene in the two homozygous mutant backgrounds rescued the accelerated cell death phenotypes. Together, our results provide direct genetic evidence for a role of BI-1 as an attenuator for cell death progression triggered by both biotic and abiotic types of cell death signals in Arabidopsis.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Apoptosis*
  • Arabidopsis / anatomy & histology
  • Arabidopsis / genetics
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / physiology*
  • Base Sequence
  • DNA, Bacterial / genetics
  • Fumonisins / pharmacology
  • Hot Temperature
  • Membrane Proteins / genetics
  • Membrane Proteins / physiology*
  • Molecular Sequence Data
  • Mutagenesis, Insertional
  • Mutation
  • Phenotype
  • Plant Leaves / anatomy & histology
  • Plant Leaves / drug effects
  • Plant Leaves / metabolism
  • Signal Transduction / genetics
  • Transgenes
  • Up-Regulation


  • ATBI-1 protein, Arabidopsis
  • Arabidopsis Proteins
  • DNA, Bacterial
  • Fumonisins
  • Membrane Proteins
  • T-DNA
  • fumonisin B1