Regulation of gliotoxin biosynthesis and protection in Aspergillus species

  • Castro PA de
  • , Ana Cristina Colabardini
  • , Maísa Moraes
  • , Maria Augusta Crivelente Horta
  • , Sonja L. Knowles
  • , Huzefa A. Raja
  • , Nicholas H. Oberlies
  • , Yasuji Koyama
  • , Masahiro Ogawa
  • , Katsuya Gomi
  • , Jacob L. Steenwyk
  • , Antonis Rokas
  • , Relber A. Gonçales
  • , Cláudio Duarte-Oliveira
  • , Agostinho Carvalho
  • , Laure N.A. Ries*
  • , Gustavo H. Goldman*
  • *Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

<jats:p><jats:italic>Aspergillus fumigatus</jats:italic> causes a range of human and animal diseases collectively known as aspergillosis. <jats:italic>A</jats:italic>. <jats:italic>fumigatus</jats:italic> possesses and expresses a range of genetic determinants of virulence, which facilitate colonisation and disease progression, including the secretion of mycotoxins. Gliotoxin (GT) is the best studied <jats:italic>A</jats:italic>. <jats:italic>fumigatus</jats:italic> mycotoxin with a wide range of known toxic effects that impair human immune cell function. GT is also highly toxic to <jats:italic>A</jats:italic>. <jats:italic>fumigatus</jats:italic> and this fungus has evolved self-protection mechanisms that include (i) the GT efflux pump GliA, (ii) the GT neutralising enzyme GliT, and (iii) the negative regulation of GT biosynthesis by the <jats:italic>bis</jats:italic>-thiomethyltransferase GtmA. The transcription factor (TF) RglT is the main regulator of GliT and this GT protection mechanism also occurs in the non-GT producing fungus <jats:italic>A</jats:italic>. <jats:italic>nidulans</jats:italic>. However, the <jats:italic>A</jats:italic>. <jats:italic>nidulans</jats:italic> genome does not encode GtmA and GliA. This work aimed at analysing the transcriptional response to exogenous GT in <jats:italic>A</jats:italic>. <jats:italic>fumigatus</jats:italic> and <jats:italic>A</jats:italic>. <jats:italic>nidulans</jats:italic>, two distantly related <jats:italic>Aspergillus</jats:italic> species, and to identify additional components required for GT protection. RNA-sequencing shows a highly different transcriptional response to exogenous GT with the RglT-dependent regulon also significantly differing between <jats:italic>A</jats:italic>. <jats:italic>fumigatus</jats:italic> and <jats:italic>A</jats:italic>. <jats:italic>nidulans</jats:italic>. However, we were able to observe homologs whose expression pattern was similar in both species (43 RglT-independent and 11 RglT-dependent). Based on this approach, we identified a novel RglT-dependent methyltranferase, MtrA, involved in GT protection. Taking into consideration the occurrence of RglT-independent modulated genes, we screened an <jats:italic>A</jats:italic>. <jats:italic>fumigatus</jats:italic> deletion library of 484 transcription factors (TFs) for sensitivity to GT and identified 15 TFs important for GT self-protection. Of these, the TF KojR, which is essential for kojic acid biosynthesis in <jats:italic>Aspergillus oryzae</jats:italic>, was also essential for virulence and GT biosynthesis in <jats:italic>A</jats:italic>. <jats:italic>fumigatus</jats:italic>, and for GT protection in <jats:italic>A</jats:italic>. <jats:italic>fumigatus</jats:italic>, <jats:italic>A</jats:italic>. <jats:italic>nidulans</jats:italic>, and <jats:italic>A</jats:italic>. <jats:italic>oryzae</jats:italic>. KojR regulates <jats:italic>rglT</jats:italic>, <jats:italic>gliT</jats:italic>, <jats:italic>gliJ</jats:italic> expression and sulfur metabolism in <jats:italic>Aspergillus</jats:italic> species. Together, this study identified conserved components required for GT protection in <jats:italic>Aspergillus</jats:italic> species.</jats:p>
Original languageEnglish
Pages (from-to)e1009965-e1009965
Number of pages0
JournalPLoS Genetics
Volume18
Issue number1
DOIs
Publication statusE-pub ahead of print - 18 Jan 2022

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