Dataset Information

The FlbA-regulated predicted transcription factor Fum21 of Aspergillus niger is involved in fumonisin production.

ABSTRACT: Aspergillus niger secretes proteins throughout the colony except for the zone that forms asexual spores called conidia. Inactivation of flbA that encodes a regulator of G-protein signaling results in colonies that are unable to reproduce asexually and that secrete proteins throughout the mycelium. In addition, the ?flbA strain shows cell lysis and has thinner cell walls. Expression analysis showed that 38 predicted transcription factor genes are differentially expressed in strain ?flbA. Here, the most down-regulated predicted transcription factor gene, called fum21, was inactivated. Growth, conidiation, and protein secretion were not affected in strain ?fum21. Whole genome expression analysis revealed that 63 and 11 genes were down- and up-regulated in ?fum21, respectively, when compared to the wild-type strain. Notably, 24 genes predicted to be involved in secondary metabolism were down-regulated in ?fum21, including 10 out of 12 genes of the fumonisin cluster. This was accompanied by absence of fumonisin production in the deletion strain and a 25% reduction in production of pyranonigrin A. Together, these results link FlbA-mediated sporulation-inhibited secretion with mycotoxin production.

SUBMITTER: Aerts D

PROVIDER: S-EPMC5816093 | biostudies-literature | 2018 Mar

REPOSITORIES: biostudies-literature

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The FlbA-regulated predicted transcription factor Fum21 of Aspergillus niger is involved in fumonisin production.

Aerts David D Hauer Esther E EE Ohm Robin A RA Arentshorst Mark M Teertstra Wieke R WR Phippen Christopher C Ram Arthur F J AFJ Frisvad Jens C JC Wösten Han A B HAB

Antonie van Leeuwenhoek 20170930 3

Aspergillus niger secretes proteins throughout the colony except for the zone that forms asexual spores called conidia. Inactivation of flbA that encodes a regulator of G-protein signaling results in colonies that are unable to reproduce asexually and that secrete proteins throughout the mycelium. In addition, the ΔflbA strain shows cell lysis and has thinner cell walls. Expression analysis showed that 38 predicted transcription factor genes are differentially expressed in strain ΔflbA. Here, th ...[more]

PMID: 28965153

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Project description:Proteins are secreted throughout the mycelium of Aspergillus niger except for the sporulating zone. A link between sporulation and repression of protein secretion was underlined by the finding that inactivation of the sporulation gene flbA results in mycelial colonies that secrete proteins throughout the colony. However, ΔflbA strain hyphae also lyse and have thinner cell walls. This pleiotropic phenotype is associated with differential expression of 36 predicted transcription factor genes, one of which, rpnR, was inactivated in this study. Sporulation, biomass, and secretome complexity were not affected in the ΔrpnR deletion strain of the fungus. In contrast, ribosomal subunit expression and protein secretion into the medium were reduced when A. niger was grown on xylose. Moreover, the ΔrpnR strain showed decreased resistance to H2O2 and the proteotoxic stress-inducing agent dithiothreitol. Taking the data together, RpnR is involved in proteotoxic stress resistance and impacts protein secretion when A. niger is grown on xylose.IMPORTANCEAspergillus niger secretes a large amount and diversity of industrially relevant enzymes into the culture medium. This makes the fungus a widely used industrial cell factory. For instance, carbohydrate-active enzymes of A. niger are used in biofuel production from lignocellulosic feedstock. These enzymes represent a major cost factor in this process. Higher production yields could substantially reduce these costs and therefore contribute to a more sustainable economy and less dependence on fossil fuels. Enzyme secretion is inhibited in A. niger by asexual reproduction. The sporulation protein FlbA is involved in this process by impacting the expression of 36 predicted transcription factor genes. Here, we show that one of these predicted transcriptional regulators, RpnR, regulates protein secretion and proteotoxic stress resistance. The gene is thus an interesting target to improve enzyme production in A. niger.

Dataset Information

The FlbA-regulated predicted transcription factor Fum21 of Aspergillus niger is involved in fumonisin production.

Publications

The FlbA-regulated predicted transcription factor Fum21 of Aspergillus niger is involved in fumonisin production.

Similar Datasets

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