Salt and Metal Tolerance Involves Formation of Guttation Droplets in Species of the Aspergillus versicolor Complex

Genes (Basel). 2022 Sep 11;13(9):1631. doi: 10.3390/genes13091631.

Abstract

Three strains of the Aspergillus versicolor complex were isolated from a salty marsh at a former uranium mining site in Thuringia, Germany. The strains from a metal-rich environment were not only highly salt tolerant (up to 20% NaCl), but at the same time could sustain elevated Cs and Sr (both up to 100 mM) concentrations as well as other (heavy) metals present in the environment. During growth experiments when screening for differential cell morphology, the occurrence of guttation droplets was observed, specifically when elevated Sr concentrations of 25 mM were present in the media. To analyze the potential of metal tolerance being promoted by these excretions, proteomics and metabolomics of guttation droplets were performed. Indeed, proteins involved in up-regulated metabolic activities as well as in stress responses were identified. The metabolome verified the presence of amino sugars, glucose homeostasis-regulating substances, abscisic acid and bioactive alkaloids, flavones and quinones.

Keywords: Aspergillus; heavy metals; mycobiome; post-mining environments; salt stress.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abscisic Acid
  • Amino Sugars
  • Aspergillus
  • Flavones*
  • Glucose
  • Quinones
  • Sodium Chloride
  • Uranium*

Substances

  • Amino Sugars
  • Flavones
  • Quinones
  • Sodium Chloride
  • Uranium
  • Abscisic Acid
  • Glucose

Supplementary concepts

  • Aspergillus versicolor

Grants and funding

This research was funded by Deutsche Forschungsgemeinschaft (DFG; CRC 1127 project ID 239748522 and CRC 124 FungiNet project Z2, ID 210879364, and under Germany’s Èxcellence Strategy project ID 390713860). Further funding was obtained through the BMBF (project USER II).