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Peptide synthetase gene in Trichoderma virens.
S E Wilhite1, R D Lumsden, D C Straney
1Department of Cell Biology & Molecular Genetics, University of Maryland, College Park, Maryland 20742-5815, USA.
Applied and Environmental Microbiology
|October 27, 2001
Summary
Trichoderma virens peptide synthetase (Psy1) is crucial for siderophore production, aiding iron acquisition. Disrupting Psy1 impairs dimerum acid synthesis but does not affect biocontrol efficacy against common plant pathogens.
Area of Science:
- Mycology
- Plant Pathology
- Biochemistry
Background:
- Trichoderma virens is a biocontrol agent used to suppress soilborne plant diseases.
- Antagonistic interactions of T. virens involve peptide metabolites like gliotoxin and siderophores.
Purpose of the Study:
- To clone and characterize the peptide synthetase (Psy1) gene in T. virens.
- To investigate the role of Psy1 in siderophore production and biocontrol activity.
Main Methods:
- Cloning of a partial cDNA encoding putative peptide synthetase (Psy1).
- Gene replacement to create Psy1 disruptants.
- Analysis of gliotoxin and siderophore production.
- Assessment of biocontrol activity against Pythium ultimum and Rhizoctonia solani.
Main Results:
- The Psy1 gene was identified as encoding a peptide synthetase.
- Psy1 disruptants produced normal gliotoxin but grew poorly under low-iron conditions.
- Psy1 disruption prevented the production of the siderophore dimerum acid.
- Biocontrol activity against damping-off diseases remained unaffected.
Conclusions:
- Psy1 is essential for siderophore production, specifically dimerum acid, in T. virens.
- Iron competition via dimerum acid is not a primary mechanism for T. virens biocontrol in this study.