The transcriptional activator GaaR of Aspergillus niger is required for release and utilization of d‐galacturonic acid from pectin

• Published in: FEBS letters Vol. 590; no. 12; pp. 1804 - 1815
• Main Authors: Alazi, Ebru, Niu, Jing, Kowalczyk, Joanna E., Peng, Mao, Aguilar Pontes, Maria Victoria, Kan, Jan A. L., Visser, Jaap, Vries, Ronald P., Ram, Arthur F. J.
• Format: Journal Article
• Language: English
• Published: England Federation of European Biochemical Societies 01.06.2016; John Wiley and Sons Inc
• Subjects: Aspergillus niger - genetics; Aspergillus niger - metabolism; Biological Transport, Active - physiology; EPS; Fungal Proteins - genetics; Fungal Proteins - metabolism; Gene Deletion; gene regulation; Genome-Wide Association Study; GEOSCIENCES; Hexuronic Acids - metabolism; Laboratorium voor Fytopathologie; Laboratorium voor Phytopathologie; Laboratory of Phytopathology; pectinase; Pectins - metabolism; polygalacturonic acid; Research Letter; Research Letters; Trans-Activators - genetics; Trans-Activators - metabolism; transcriptomics; Zn2Cys6 transcription factor; transcriptomics; Zn2Cys6 transcription factor; gene regulation; pectinase; polygalacturonic acid
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1002/1873-3468.12211

We identified the d‐galacturonic acid (GA)‐responsive transcriptional activator GaaR of the saprotrophic fungus, Aspergillus niger, which was found to be essential for growth on GA and polygalacturonic acid (PGA). Growth of the ΔgaaR strain was reduced on complex pectins. Genome‐wide expression analysis showed that GaaR is required for the expression of genes necessary to release GA from PGA and more complex pectins, to transport GA into the cell, and to induce the GA catabolic pathway. Residual growth of ΔgaaR on complex pectins is likely due to the expression of pectinases acting on rhamnogalacturonan and subsequent metabolism of the monosaccharides other than GA.