THE AARC GENE RESPONSIBLE FOR ACETIC-ACID ASSIMILATION CONFERS ACETIC-ACID RESISTANCE ON ACETOBACTER-ACETI

Acetic acid resistance, which characterizes the genus Acetobacter, is conferred by three genes designated aarA, aarB, and aarC. The nucleotide sequence of aarC revealed that it coded for a protein of 492 amino acid residues. This gene product showed significant homology, with 44% identity, with the Neurospora crassa acu-8 gene product which is involved in acetate-utilization in this fungus. Consistent with this, an aarC-defective mutant, which was constructed by gene disruption with the cloned gene, showed an inability to assimilate acetic acid. Introduction of the aarC gene into the mutant restored both the resistance to acetic acid and the ability to assimilate acetic acid. These findings suggested that the aarC gene product was responsible for acetate assimilation and that the acetate-sensitive phenotype of the aarC mutant was caused by a defect in acetate assimilation.