Purification, characterization and in vivo biocontrol efficiency of killer toxins from Debaryomyces hansenii strains

Int J Biol Macromol. 2018 Nov;119:1077-1082. doi: 10.1016/j.ijbiomac.2018.07.121. Epub 2018 Jul 19.

Abstract

Nowadays, the biological control of various yeast and mold pathogens that cause diseases in humans, animals, and plants is an increasing of interest. The discovery of novel agents allows prevention of infectious diseases and post-harvest losses reported every year. In the study, we aimed to investigate the production, purification, and characterization as well as in vivo biocontrol efficiency of killer toxins produced by Debaryomyces hansenii strains TEM8 and TEM17. The molecular mass of the killer toxins was 31.5 kDa and they showed high stability at pHs between 2.5 and 5.5 and up to 37 °C. Their internal amino acid sequences matched the DEHA2G18766g (CAG90862.1) from D. hansenii CBS767, which is similar to Saccharomyces cerevisiae YGR282C BGL2 endo-beta-1,3-glucanase. The yeasts and their purified killer toxins significantly inhibited the growth of plant pathogenic fungi Alternaria brassicicola, Alternaria citri, Aspergillus niger and Rhizopus stolonifer in fruits. The findings of this paper have recommended these yeast strains and their toxins as effective biocontrol agents against fungi that cause post-harvest diseases.

Keywords: Biocontrol; D. hansenii; Killer toxin.

MeSH terms

  • Amino Acid Sequence
  • Ascomycota / chemistry*
  • Biological Control Agents / chemistry*
  • Biological Control Agents / isolation & purification
  • Biological Control Agents / pharmacology*
  • Enzyme Activation
  • Hydrogen-Ion Concentration
  • Mass Spectrometry
  • Mycotoxins / chemistry*
  • Mycotoxins / isolation & purification
  • Mycotoxins / pharmacology*
  • Proteolysis
  • Temperature

Substances

  • Biological Control Agents
  • Mycotoxins