Project description:The genome of the osmophilic Aspergillus wentii, unlike that of the osmotolerant Aspergillus nidulans, contains only the gfdA but not the gfdB glycerol 3-phosphate dehydrogenase gene. Here, we studied transcriptomic changes of A. nidulans (reference strain and DgfdB gene deletion mutant) and A. wentii (reference strain and An-gfdB expressing mutant) elicited by high osmolarity. A. nidulans showed canonic hyperosmotic stress response characterized by upregulation of trehalose and glycerol metabolism genes (including gfdB) as well as genes of the high-osmolarity glycerol (HOG) map kinase pathway. Deletion of gfdB caused only negligible alterations in the transcriptome suggesting that the glycerol metabolism was flexible enough to compensate for the missing GfdB activity in this species. A. wentii responded differently to increased osmolarity than A. nidulans: E.g.; bulk upregulation of glycerol and trehalose metabolism genes as well as HOG pathway genes were not detected. Expression of An-gfdB in A. wentii did not abolish osmophilia, but it reduced growth and caused much bigger alterations in the transcriptome than the missing gfdB gene did in A. nidulans. Flexible glycerol metabolism and hence two differently regulated gfd genes may be more beneficial for osmotolerant (living under changing osmolarity) than for osmophilic (living under constantly high osmolarity) species.
Project description:Investigation of whole genome gene expression level changes in Aspergillus nidulans AN1599 (PbcR) overexpression mutant, compared to the FGSC A4 wild-type strain. Overexpression of the Zn(II)2Cys6 –type transcription factor, AN1599.4 (PbcR, pimaradiene biosynthetic cluster regulator), activates a secondary metabolite gene cluster in Aspergillus nidulans. Activation of the pathway in Aspergillus nidulans lead to a production of ent-pimara-8(14),15-diene.
Project description:Using transcriptomics, the strain-specific metabolism was mapped for two whole-genome sequenced strains of Aspergillus niger Keywords: Strain comparison
Project description:Aspergillus flavus and A. parasiticus are two of the most important aflatoxin-producing species that contaminate agricultural commodities worldwide. Both species are heterothallic and undergo sexual reproduction in laboratory crosses. Here, we examine the possibility of interspecific matings between A. flavus and A. parasiticus. These species can be distinguished morphologically and genetically, as well as by their mycotoxin profiles. Aspergillus flavus produces both B aflatoxins and cyclopiazonic acid (CPA), B aflatoxins or CPA alone, or neither mycotoxin; Aspergillus parasiticus produces B and G aflatoxins or the aflatoxin precursor O-methylsterigmatocystin, but not CPA. Only four out of forty-five attempted interspecific crosses between compatible mating types of A. flavus and A. parasiticus were fertile and produced viable ascospores. Single ascospore strains from each cross were isolated and were shown to be recombinant hybrids using multilocus genotyping and array comparative genome hybridization. Conidia of parents and their hybrid progeny were haploid and predominantly monokaryons and dikaryons based on flow cytometry. Multilocus phylogenetic inference showed that experimental hybrid progeny were grouped with naturally occurring A. flavus L strain and A. parasiticus. Higher total aflatoxin concentrations in some F1 progeny strains compared to midpoint parent aflatoxin levels indicate synergism in aflatoxin production; moreover, three progeny strains synthesized G aflatoxins that were not produced by the parents, and there was evidence of putative allopolyploidization in one strain. These results suggest that hybridization is an important diversifying force resulting in the genesis of novel toxin profiles in these agriculturally important species.
Project description:Experimantal validation for the 5' end of poly(A)-RNA in Aspergillus fumigatus is currently lacking. Therefore we performed 5'RNA-End sequencing from 24-h mycelium grown in AMM at 37°C and 42°C with a library prepration kit purchased from Eclipse Bioinnovations.