Trichoderma atroviride suppresses Fusarium graminearum by altering primary and secondary metabolite biosynthesis profiling

Abstract

The use of Trichoderma spp. offers an ecologically friendly tool for the struggle with mycotoxigenic Fusarium spp. Here, the alterations in transcriptome level were investigated in 6-day- old Fusarium graminearum cultures treated with Trichoderma atroviride and nontreated with T. atroviride (FGc), using whole transcriptome sequencing to better understand the associated biological processes. Transcriptome analysis indicated a total of 55 up-regulated genes and 728 down-regulated genes with padj < 0.05. Enrichment analysis revealed that the up-regulated genes were related to fatty acid biosynthesis, AMP-dependent biosynthesis, amino acid recognition/activation processes and secondary metabolite production, whereas down-regulated genes were involved in amino acid synthesis, oxidation–reduction processes, metal ion-binding and metabolic/ catalytic activities. Among the down-regulated genes, the expression of pigmentation-related genes such as aurO, gip1 and aurR2 was remarkable. Similarly, the expression levels of key enzyme-coding genes involved in deoxynivalenol mycotoxin production were significantly decreased in the range of −1.77 and −2.94. For up-regulated genes, nonribosomal peptide synthetase and polyketide synthase genes were notably distinguished from the remaining down-regulated genes as these genes can be involved in biosynthesis of common secondary metabolites. The results clearly emphasize that T. atroviride repressed the biosynthesis of primary metabolites in F. graminearum while simultaneously up-regulating the expression of genes involved in the synthesis of secondary metabolites. This is the first report showing how T. atroviride leads to transcriptome alterations and the findings suggest that T. atroviride could serve as an effective fungus by employing a wide variety of strategies against phytopathogenic fungi.