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

作者：Fekete Erzsebet; de Vries Ronald P; Seiboth Bernhard; vanKuyk Patricia A; Sandor Erzsebet; Fekete Eva; Metz Benjamin; Kubicek Christian P; Karaffa Levente^*

来源：FEMS Microbiology Letters, 2012, 329(2): 198-203.

DOI：10.1111/j.1574-6968.2012.02524.x

• Aspergillus niger
• d-galactose
• Leloir pathway
• uptake
• germination

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.similar to 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.similar to niger conidiospores may be due to the lack of inducer uptake.

• 出版日期2012-4