Coating seeds with Trichoderma strains promotes plant growth and enhance the systemic resistance against Fusarium crown rot in durum wheat

Background Fusarium crown rot is one of the major diseases that cause significant yield losses of wheat, and Trichoderma strains were known as an effective biocontrol agent. Main body The aim of this study was to evaluate the potential of coating durum wheat seeds of the cultivar Karim with 3 different Tunisian strains of Trichoderma sp. (S.INAT, SIO1, SIO2) and the Trichoderma-based commercial product Trianum-T22 on seed germination, seedling growth, and plant defense response against the pathogen Fusarium culmorum. The strains were identified using molecular tools based on sequencing ITS region of ribosomal DNA. The results confirmed at 99% of homology that the strains were T. harzianum. Under controlled conditions, the coating seeds were released with 400 mu l of spore suspension at 10(7) spores/ml. The seed coating with Trianum-P, and S.INAT showed the highest seed germination rates ranging from 85 to 90% while S.IO1 and S.IO2 presented the lowest germination rates with 66 and 68%, respectively. At 20 days post-infection (dpi) with F. culmorum, the treated plants with S.INAT and Trianum-T22 reduced the disease incidence by 53.59 and 51.79%, respectively than the control. Besides, S.INAT induced two-folds the phenolic compounds level compared to infected control. Further, the peroxidase activity was enhanced by 50% in average since 10 dpi in plants treated with S.INAT and SIO2 than the control. Conclusion The results suggest that seed coating with T. harzianum S.INAT was a promising tool for crop production and protection under field conditions due to both direct antagonist activity and the indirect growth promotion. This strain seems to induce the systemic resistance of plants against foot crown rot disease.