Identification and isolation of a putative permease gene in the quinic acid utilization (QUT) gene cluster of Aspergillus nidulans.

Mutations in the qutD gene of Aspergillus nidulans cause the loss of ability to grow upon quinic acid as sole carbon source in media at normal pH 6.5 and failure to induce three enzyme activities specifically required for metabolism to protochatechuic acid. All 9 qutD mutants recovered are recessive and have been found to be pH sensitive, growing strongly on quinic acid media at pH 3.5 and producing significant induced enzyme activities. These properties are consistent with the hypothesis that the QUTD gene encodes an essential component of a permease required for transport of quinate ion into mycelium at pH 6.5. The QUTD gene has been located within the cloned QUT gene cluster of A. nidulans by transformation of qutD mutants with fragments of cloned sequences from phage lambda-Q1. The QUTD locus is in a region distinct from other QUT genes and which contains sequences homologous to the QA-Y gene in the corresponding QA gene cluster of Neurospora crassa.