Aspergillus niger citrate exporter revealed by comparison of two alternative citrate producing conditions

Dorett I. Odoni, Marta Vazquez-Vilar, Merlijn P. van Gaal, Tom Schonewille, Vitor A.P. Martins Dos Santos, Juan Antonio Tamayo-Ramos, Maria Suarez-Diez, Peter J. Schaap

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Currently, there is no consensus regarding the mechanism underlying Aspergillus niger citrate biosynthesis and secretion. We hypothesise that depending on the experimental setup, extracellular citrate accumulation can have fundamentally different underlying transcriptomic landscapes. We show that varying the amount and type of supplement of an arginine auxotrophic A. niger strain results in transcriptional down-regulation of citrate metabolising enzymes in the condition in which more citrate is accumulated extracellularly. This contrasts with the transcriptional adaptations when increased citrate production is triggered by iron limitation. By combining gene expression data obtained from these two very distinct experimental setups with hidden Markov models and transporter homology approaches, we were able to compile a shortlist of the most likely citrate transporter candidates. Two candidates (An17g01710 and An09g06720m.01) were heterologously expressed in the yeast Saccharomyces cerevisiae, and one of the resultant mutants showed the ability to secrete citrate. Our findings provide steps in untangling the complex interplay of different mechanisms underlying A. niger citrate accumulation, and we demonstrate how a comparative transcriptomics approach complemented with further bioinformatics analyses can be used to pinpoint a fungal citrate exporter.

Original languageEnglish
Article numberfnz071
JournalFEMS Microbiology Letters
Volume366
Issue number7
DOIs
Publication statusPublished - 1 Apr 2019

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Aspergillus niger
Citric Acid
Computational Biology
Saccharomyces cerevisiae
Arginine
Down-Regulation
Iron
Yeasts
Gene Expression
Enzymes

Keywords

  • Aspergillus niger
  • citrate
  • homology
  • MDR
  • transcriptomics
  • transport

Cite this

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title = "Aspergillus niger citrate exporter revealed by comparison of two alternative citrate producing conditions",
abstract = "Currently, there is no consensus regarding the mechanism underlying Aspergillus niger citrate biosynthesis and secretion. We hypothesise that depending on the experimental setup, extracellular citrate accumulation can have fundamentally different underlying transcriptomic landscapes. We show that varying the amount and type of supplement of an arginine auxotrophic A. niger strain results in transcriptional down-regulation of citrate metabolising enzymes in the condition in which more citrate is accumulated extracellularly. This contrasts with the transcriptional adaptations when increased citrate production is triggered by iron limitation. By combining gene expression data obtained from these two very distinct experimental setups with hidden Markov models and transporter homology approaches, we were able to compile a shortlist of the most likely citrate transporter candidates. Two candidates (An17g01710 and An09g06720m.01) were heterologously expressed in the yeast Saccharomyces cerevisiae, and one of the resultant mutants showed the ability to secrete citrate. Our findings provide steps in untangling the complex interplay of different mechanisms underlying A. niger citrate accumulation, and we demonstrate how a comparative transcriptomics approach complemented with further bioinformatics analyses can be used to pinpoint a fungal citrate exporter.",
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Aspergillus niger citrate exporter revealed by comparison of two alternative citrate producing conditions. / Odoni, Dorett I.; Vazquez-Vilar, Marta; van Gaal, Merlijn P.; Schonewille, Tom; Martins Dos Santos, Vitor A.P.; Tamayo-Ramos, Juan Antonio; Suarez-Diez, Maria; Schaap, Peter J.

In: FEMS Microbiology Letters, Vol. 366, No. 7, fnz071, 01.04.2019.

Research output: Contribution to journalArticleAcademicpeer-review

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AU - Odoni, Dorett I.

AU - Vazquez-Vilar, Marta

AU - van Gaal, Merlijn P.

AU - Schonewille, Tom

AU - Martins Dos Santos, Vitor A.P.

AU - Tamayo-Ramos, Juan Antonio

AU - Suarez-Diez, Maria

AU - Schaap, Peter J.

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