Effect of Streptomyces spp. metabolites and the combination of biochar and compost on Fusarium graminearum inhibition, triticale growth, and soil properties

Fusarium graminearum is the most harmful pathogen associated with Fusarium Head Blight (FHB) disease in triticale. Among the strategies that can be envisaged for its control, the reuse of organic residues for the production of secondary metabolites from Streptomyces spp. is particularly promising. The study presented herein focuses on the assessment of the antagonistic capacity of the culture filtrates of Streptomyces rochei alone, with compost, with biochar or with both of them, and their culture filtrates against F. graminearum. Firstly, the secondary metabolites were characterized by gas chromatography-mass spectrometry, with 5-Hydroxymethylfurfural, 2-3 Butanediol, Oxime-, methoxy-phenyl and acid butanoic being the most abundant chemical species. Subsequently, the capacity of S. rochei to inhibit the growth of the pathogen was tested in dual culture plate assays, finding 83 % inhibition. Sporangial tests showed that the mixture of S. rochei and biochar can inhibit 100 % of sporangia germination. Micropot trials conducted on triticale using the crop filtrates not only inhibited pathogen growth with all treatments but also improved crop growth. Hence, the culture filtrates of biochar, compost, compost and biochar, and the selected Streptomyces spp. culture filtrates may be put forward as promising protection treatments for the sustainable control of fusariosis.