A screen of activation-tagged T-DNA Arabidopsis mutants on monosodium
fluoroacetate was conducted to isolate acetate non-utilising mutants that had
perturbations to their acetate metabolism or acetate signalling. This work is part of an ongoing study into acetate metabolism and signalling. Two of the fluoroacetate resistant mutants that were acetate hypersensitive were found to be allelic to acn1-1, a previously identified fluoroacetate-resistant EMS mutant. The acn1 mutation was found to be due to a disrupted AMP-binding protein. This AMP-binding protein had short-chain acyl-CoA synthetase activity and a peroxisomal targeting signal. Expression of the gene, termed ACN1/AAE7, was found to occur throughout seedling development and correlated with the observed toxicity of fluoroacetate. The conclusion to the work is that the enzyme is responsible for channelling exogenous acetate into the glyoxylate cycle during germination and early seedling development. The acn1 mutants are valuable tools to investigate both acetate metabolism and metabolic signalling in Arabidopsis.