Both authors equally contributed to the manuscript.
Heterogenic expression of genes encoding secreted proteins at the periphery of Aspergillus niger colonies
Article first published online: 16 AUG 2010
© 2010 Society for Applied Microbiology and Blackwell Publishing Ltd
Volume 13, Issue 1, pages 216–225, January 2011
How to Cite
Vinck, A., de Bekker, C., Ossin, A., Ohm, R. A., de Vries, R. P. and Wösten, H. A. B. (2011), Heterogenic expression of genes encoding secreted proteins at the periphery of Aspergillus niger colonies. Environmental Microbiology, 13: 216–225. doi: 10.1111/j.1462-2920.2010.02322.x
- Issue published online: 4 JAN 2011
- Article first published online: 16 AUG 2010
- Received 24 March, 2010; accepted 5 July, 2010.
Colonization of a substrate by fungi starts with the invasion of exploring hyphae. These hyphae secrete enzymes that degrade the organic material into small molecules that can be taken up by the fungus to serve as nutrients. We previously showed that only part of the exploring hyphae of Aspergillus niger highly express the glucoamylase gene glaA. This was an unexpected finding since all exploring hyphae are exposed to the same environmental conditions. Using GFP as a reporter, we here demonstrate that the acid amylase gene aamA, the α-glucuronidase gene aguA, and the feruloyl esterase gene faeA of A. niger are also subject to heterogenic expression within the exploring mycelium. Coexpression studies using GFP and dTomato as reporters showed that hyphae that highly express one of these genes also highly express the other genes encoding secreted proteins. Moreover, these hyphae also highly express the amylolytic regulatory gene amyR, and the glyceraldehyde-3-phosphate dehydrogenase gene gpdA. In situ hybridization demonstrated that the high expressers are characterized by a high 18S rRNA content. Taken together, it is concluded that two subpopulations of hyphae can be distinguished within the exploring mycelium of A. niger. The experimental data indicate that these subpopulations differ in their transcriptional and translational activity.