D-Galactose uptake is nonfunctional in the conidiospores of Aspergillus niger

TY - JOUR

T1 - D-Galactose uptake is nonfunctional in the conidiospores of Aspergillus niger

AU - Fekete, E.

AU - de Vries, R.P.

AU - Seiboth, B.

AU - vanKuyk, P.A.

AU - Sandor, E.

AU - Metz, B.

AU - Kubicek, C.P.

AU - Karaffa, L.

N1 - Reporting year: 2012

PY - 2012

Y1 - 2012

N2 - The majority of black Aspergilli (Aspergillus section Nigri), including Aspergillus niger, as well as many other Ascomycetes fail to germinate on d-galactose as a sole carbon source. Here, we provide evidence that the ability of A. niger to transport d-galactose is growth stage dependent, being absent in the conidiospores but present in the mycelia. Despite earlier claims, we could identify galactokinase activity in growing cells and all genes of the Leloir pathway (responsible for channelling d-galactose into the EMP pathway) are well induced on d-galactose (and also on lactose, d-xylose and l-arabinose) in the mycelial stage. Expression of all Leloir pathway genes was also detectable in conidiospores, although galE (encoding a galactokinase) and galD (encoding a galactose-1-phosphate uridylyl transferase) were expressed poorly. These results suggest that the d-galactose-negative phenotype of A. niger conidiospores may be due to the lack of inducer uptake. Keywords: Aspergillus niger; d-galactose; Leloir pathway; uptake; germination

AB - The majority of black Aspergilli (Aspergillus section Nigri), including Aspergillus niger, as well as many other Ascomycetes fail to germinate on d-galactose as a sole carbon source. Here, we provide evidence that the ability of A. niger to transport d-galactose is growth stage dependent, being absent in the conidiospores but present in the mycelia. Despite earlier claims, we could identify galactokinase activity in growing cells and all genes of the Leloir pathway (responsible for channelling d-galactose into the EMP pathway) are well induced on d-galactose (and also on lactose, d-xylose and l-arabinose) in the mycelial stage. Expression of all Leloir pathway genes was also detectable in conidiospores, although galE (encoding a galactokinase) and galD (encoding a galactose-1-phosphate uridylyl transferase) were expressed poorly. These results suggest that the d-galactose-negative phenotype of A. niger conidiospores may be due to the lack of inducer uptake. Keywords: Aspergillus niger; d-galactose; Leloir pathway; uptake; germination

U2 - 10.1111/j.1574-6968.2012.02524.x

DO - 10.1111/j.1574-6968.2012.02524.x

M3 - Article

SN - 0378-1097

VL - 329

SP - 198

EP - 203

JO - FEMS Microbiology Letters

JF - FEMS Microbiology Letters

IS - 2

ER -