|Dombrink Kurtzman, Mary Ann|
Submitted to: Current Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/24/2007
Publication Date: 1/1/2008
Citation: Dombrink Kurtzman, M. 2008. A gene having sequence homology to isoamyl alcohol oxidase is transcribed during patulin production in Penicillium griseofulvum. Current Microbiology. 56:224-228. Interpretive Summary: Total genomic DNA of Penicillium griseofulvum known to make the mycotoxin patulin was analyzed. Based on the premise that genes for the patulin biosynthetic pathway are arranged in a cluster, as is the case for other mycotoxins, GeneWalking was used to determine the sequence of genes on both sides of the isoepoxydon dehydrogenase (idh) gene. From this work, an isoamyl alcohol oxidase gene was detected for the first time in a species of Penicillium. This information relates to food safety and benefits both producers of apple juice and consumers. Patulin, which is common to apples, is one of two mycotoxins regulated by the U.S. Food and Drug Administration.
Technical Abstract: The genes for the patulin biosynthetic pathway are most likely arranged in a cluster, as is often the case for other mycotoxins. With this in mind, GeneWalking has been performed to identify genes both upstream and downstream of the isoepoxydon dehydrogenase (idh) gene. A gene present in Penicillium griseofulvum NRRL 2159A had high sequence homology to the isoamyl alcohol oxidase (iao) gene and was detected downstream of the idh gene and in the same orientation. By virtue of the presence of a signal peptide sequence, the newly identified gene coded for a secreted protein with an FAD-binding domain and potential for N-glycosylation. An open reading frame consisted of 1943 nucleotides, containing four introns and encoding a 22 amino acid signal peptide. The 571 amino acid mature protein contained seven cysteine residues and had 11 potential N-linked glycosylation sites. Searches using GenBank indicated that Aspergillus terreus, A. oryzae, A. fumigatus, and Gibberella zeae contain genes coding for a putative isoamyl alcohol oxidase. When the translated query was compared with the translated database, the highest scores were seen with A. terreus (E value of 5e-143), and A. oryzae, A. fumigatus, and G. zeae (each having an E value of 3e-142). Upstream of the idh gene and in the opposite orientation, the partial sequence of a gene with homology to an ABC transporter gene was detected. This is the first report of an isoamyl alcohol oxidase gene in species of the genus Penicillium.