The unique role of siderophore in marine-derived Aureobasidium pullulans HN6.2

Abstract

The L -ornithine-N (5)-monooxygenase structural gene (SidA gene, accession number: FJ769160) was isolated from both the genomic DNA and cDNA of the marine yeast Aureobasidium pullulans HN6.2 by inverse PCR and RT-PCR. An open reading frame of 1,461 bp encoding a 486 amino acid protein (isoelectric point: 7.79) with calculated molecular weight of 55.4 kDa was characterized. The promoter of the gene (intronless) was located from -1 to -824 and had three HGATAR boxes which were putative binding motifs for the respective DNA-binding motifs and one CATA box. The SidA gene in A. pullulans HN6.2 was disrupted by integrating the hygromycin B phosphotransferase (HPT) gene into Open Reading Frame of the SidA gene using homologous recombination. Of all the disruptants obtained, one strain S6 (∆sidA) did not synthesize both intracellular and extracellular fusigen so that it could not inhibit growth of the pathogenic bacteria Vibrio anguillarum and Vibrio parahaemolyticus. The disruptant S6 did not grow in the iron-deplete medium and seawater medium because cell budding was stopped, but could grow in the iron-replete medium with 10 μM Fe(3+) and Fe(2+). H(2)O(2) in the medium was more toxic to the disruptant S6 than to its wild type HN6.2. Thus, we infer that the fusigen produced by the marine-derived A. pullulans HN6.2 can play a unique role in chelating, uptake and concentration of iron to maintain certain proper physiological functions within the cells and secretion of siderophore may represent an efficient tool to eliminate competitors to compete for limiting nutritional resources in marine environments.

Biotechnology of siderophores in high-impact scientific fields

“…Another siderophore presenting antimicrobial properties is fusigen, produced by the yeast Aureobasidium pullulans (32,33). Wang et al (33) presented the siderophore screening of 300 yeast species confirming the production of fusigen by the previously mentioned A. pullulans.…”

“…The antimicrobial activity of fusigen were confirmed in the marine pathogens Vibrio anguillarum and Vibrio parahaemolyticus. In a following report, investigators disrupted the sidA gene encoding for the siderophore and the yeast did not show antimicrobial activity against the previously mentioned marine pathogens (32). Recent genome sequencing studies showed that A. pullulans contains certain clusters of non-ribosomal peptide synthetases (NRPS) (41), which are enzymes involved in siderophore biosynthetic pathways (8,72).…”

Overexpression of an Inulinase Gene in an Oleaginous Yeast, <b><i>Aureobasidium melanogenum</i></b> P10, for Efficient Lipid Production from Inulin

“…An extracellular protease producing Aureobasidium pullulans HN6.2 was isolated from the sediment of the sea saltern in Qingdao, China [Chi et al, 2011b] [Wang et al, 2014b]. KM, which was a high exoinulinase producer was grown in the inulinase production medium [Zhou et al, 2014].…”

“…A plasmid pCAM-BIA1381 carrying a bacterial hygromycin B phosphotransferase gene (HPT) was kindly offered by Dr. Lining Zhang in Canada [Chi et al, 2011b].…”

“…Restriction endonuclease digestions and DNA ligations and the transformation of E. coli with a plasmid DNA were conducted according to Sambrook et al [1989]. A. melanogenum strain P10 was transformed according to the methods described by Chi et al [2011b].…”