Evaluation of agro-active metabolite production in the co-culture of Bacillus subtilis PE7 and Bacillus amyloliquefaciens N3S

Bacterial antagonists have gained great attention for their dual roles in plant growth promotion and disease control to reduce extensive use of agrochemicals in sustainable agriculture.This study demonstrates the mutualistic growth of Bacillus subtilis PE7 and Bacillus amyloliquefaciens N3S in a co-culture system and their production of agro-active substances including indole-3-acetic acid (IAA) and antifungal metabolites compared with their corresponding monocultures.Although a cooperative growth of two Bacillus strains was observed, IAA production in the co-culture was lower than those in the monocultures.The culture filtrates (CFs) of strain N3S monoculture showed the highest inhibitory action on mycelial growth of Sclerotinia sclerotiorum.In addition, the antifungal activity of the CFs of the co-culture was stronger than that of strain PE7 monoculture.Treatment of S. sclerotiorum with the CFs of the monocultures and co-culture induced the severe distortions in the hyphal morphology.The cooperative growth as well as metabolite production of two Bacillus species in the co-culture highlights the potential of bacterial consortium for the development of effective biofertilizer and biofungicide in green agriculture.