Effects of SG3403 and 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.