Effects of Trichoderma atroviride SG3403 and Bacillus subtilis 22 on the Biocontrol of Wheat Head Blight.

Wheat head blight caused by is one of the major wheat diseases in the world; therefore, it is very significant to develop an effective and environmentally friendly microbial fungicide against it. and are widely applied biocontrol microorganisms with separate advantages; however, little work has been conducted for synergistically elevating the effects of biocontrol and plant promotion through the co-cultivation of the two microorganisms. Our study demonstrated that SG3403 is compatible with 22. The co-culture metabolites contained a group of antagonistic compounds which were able to inhibit growth and increase the activities of pathogen G protein and mitogen-activated protein kinase (MAPK) as compared with axenic culture metabolites. Additionally, the co-culture metabolites enabled us to more significantly decrease the production of gibberellin (GA), deoxynivalenol (DON), and zearalenone (ZEN) from , which disorganized the subcellular structure, particularly the cytoplasm of hyphae, relative to the axenically cultured metabolites. Furthermore, the seed-coating agent made by the co-culture had significant effects against infection by triggering the expression of host plant defensive genes, including , , , , , and . It is suggested that jasmonic acid and ethylene (JA/ET) signaling might dominate wheat's induced systemic resistance (ISR) against wheat head blight. A dry, powdered bio-seed coating agent containing the co-culture mixtures was confirmed to be a bioavailable formulation that can be applied to control wheat head blight. Taken together, the co-culture's metabolites or the metabolites and living cells might provide a basis for the further development of a new kind of microbial bio-fungicide in the future.