Heterogenic expression of genes encoding secreted proteins at the periphery of Aspergillus niger colonies.
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.
Vinck
Arman
A
Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
de Bekker
Charissa
C
Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
Ossin
Adam
A
Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
Ohm
Robin A
RA
Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
de Vries
Ronald P
RP
Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
Wösten
Han A B
HAB
Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
D001234:Aspergillus niger / Q000201:enzymology* / Q000235:genetics; D002265:Carboxylic Ester Hydrolases / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D005087:Glucan 1,4-alpha-Glucosidase / Q000235:genetics / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000235:genetics / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D025301:Hyphae / Q000201:enzymology* / Q000235:genetics; D011401:Promoter Regions, Genetic
D005656:Fungal Proteins; D049452:Green Fluorescent Proteins; D002265:Carboxylic Ester Hydrolases; C070196:feruloyl esterase; D006026:Glycoside Hydrolases; C096734:alpha-glucuronidase; D005087:Glucan 1,4-alpha-Glucosidase