Biological role of Trichoderma harzianum-derived platelet-activating factor acetylhydrolase (PAF-AH) on stress response and antagonism

PLoS One. 2014 Jun 25;9(6):e100367. doi: 10.1371/journal.pone.0100367. eCollection 2014.

Abstract

We investigated the properties of platelet-activating factor acetylhydrolase (PAF-AH) derived from Trichoderma harzianum. The enzyme, comprised of 572 amino acids, shares high homology with PAF-AH proteins from T. koningii and other microbial species. The optimum enzymatic activity of PAF-AH occurred at pH 6 in the absence of Ca2+ and it localized in the cytoplasm, and we observed the upregulation of PAF-AH expression in response to carbon starvation and strong heat shock. Furthermore, PAF-AH knockout transformant growth occurred more slowly than wild type cells and over-expression strains grown in SM medium at 37°C and 42°C. In addition, PAF-AH expression significantly increased under a series of maize root induction assay. Eicosanoic acid and ergosterol levels decreased in the PAF-AH knockouts compared to wild type cells, as revealed by GC/MS analysis. We also determined stress responses mediated by PAF-AH were related to proteins HEX1, Cu/Zn superoxide dismutase, and cytochrome c. Finally, PAF-AH exhibited antagonistic activity against Rhizoctonia solani in plate confrontation assays. Our results indicate PAF-AH may play an important role in T. harzianum stress response and antagonism under diverse environmental conditions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 1-Alkyl-2-acetylglycerophosphocholine Esterase / deficiency
  • 1-Alkyl-2-acetylglycerophosphocholine Esterase / genetics
  • 1-Alkyl-2-acetylglycerophosphocholine Esterase / metabolism*
  • Cloning, Molecular
  • Fatty Acids / metabolism
  • Gene Knockout Techniques
  • Intracellular Space / metabolism
  • Protein Transport
  • Rhizoctonia / physiology
  • Sterols / metabolism
  • Stress, Physiological*
  • Transformation, Genetic
  • Trichoderma / cytology
  • Trichoderma / enzymology*
  • Trichoderma / physiology*

Substances

  • Fatty Acids
  • Sterols
  • 1-Alkyl-2-acetylglycerophosphocholine Esterase

Grants and funding

The work was supported by a grant from the National Natural Science Foundation of China (Nos. 30971949, 31270155, 31171798) and China Agriculture Research System Project (CARS-02). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.