The combination of Trichoderma virens Gl006 and B. velezensis Bs006 as a consortium has high potential to control Fusarium wilt (FW) of cape gooseberry (Physalis peruviana) caused by Fusarium oxysporum f. sp. physali (Foph). However, the interactions between these two microorganisms that influence the biocontrol activity as a consortium have not been studied. Here, we studied the interactions between Gl006 and Bs006 that keep their compatibility under in vitro and greenhouse conditions. Antagonism tests between Gl006 and Bs006 inoculated both individually and in consortium against Foph strain Map5 was carried out on several solid media. The effect of supernatant of each selected microorganism on growth, conidia germination, biofilm formation and antagonistic activity on its partner was also studied. Biocontrol activity by different combinations of cells and supernatants from both microorganisms against Fusarium wilt was evaluated under greenhouse conditions. In vitro antagonism of the consortium against Foph showed a differential response among culture media and showed compatibility among BCA under nutritional conditions close to those of the rhizosphere. The supernatant of Bs006 did not affect the antagonistic activity of Gl006 and vice versa. However, the supernatant of Bs006 promoted the biocontrol activity of Gl006 in a synergistic way under greenhouse, reducing the disease severity by 71%. These results prove the compatibility between T. virens Gl006 and B. velezensis Bs006 as a potential tool to control Fusarium wilt of cape gooseberry.Fusarium oxysporum is the causal agent of Fusarium wilt disease in several species of cultivated plants worldwide. This phytopathogen is in the fifth place within the top ten of the most important plant pathogens due to its effects in crops of economic importance causing severe losses 1 . Fusarium wilt is the main limitation of cape gooseberry (Physalis peruviana) crop in Colombia 2 . Wilt symptoms in field include wilting of top leaves, stunting of plants, lateral yellowing of branches and leaves, some plants present both dry and alive branches. Plants finally become yellow and die, resulting in plant losses and reduced fruit yield. This phytosanitary problem has also caused the migration of cropped areas within the country, but the problem persists in old and new cropped areas 2 . Currently, there are no registered phytosanitary products for the control of this disease in cape gooseberry.In this context, biological control has emerged as an environmentally sustainable alternative. However, classical biological control in which just one biological control agent (BCA) is used has shown high variability among tests. Considering that biocontrol agents are living organisms and they may not be active in all agroecosystems 3 , many of the recent studies have focused on using combinations of BCA to increase the efficacy against phytopathogens. Those combinations are known as consortia. A consortium is a microbial association of two or more microorganisms, which could be archaea, fu...

Background and aim Fusarium wilt (FW) is the major constraint on cape gooseberry (Physalis peruviana L.) production. Fungicides have been ineffective in disease control and alternative tools are not available. Bacillus velezensis (formerly Bacillus amyloliquefaciens) strain Bs006 has an antagonistic potential against Fusarium oxysporum f. sp. physali (Foph). However, results of

Bacillus velezensis Bs006 has shown antagonistic activity on Fusarium oxysporum f. sp. physali (Foph) and biocontrol activity against Fusarium wilt (FW) in golden berry (Physalis peruviana). We hypothesized that strain Bs006 has the ability to synthesize antimicrobial cyclic lipopeptides (CLPs) like other members of the same species. However, if so, the real effects of CLPs on Foph and their potential as a biocontrol tool against Physalis-FW had not been elucidated. In this study the CLPs profile of Bs006 in liquid culture, and antagonist-plant-pathogen interactions were characterized. Also, the potential effects of supernatant free of bacteria against Foph and FW were explored and compared to the effects of pure CLPs. UPLC-ESI-MS analysis revealed the capacity of Bs006 to synthesize homologous compounds of iturins, surfactins and fengycins in liquid culture as well as on the inhibition zone against Foph in dual confrontation tests. Bs006-supernatant reduced the germination and growth of Foph and caused vacuolization, swelling and lysis of Foph cells in a concentration-dependent manner. Pure fengycins affected the development of Foph from 11 mg L-1 while iturins from 21 mg L-1. In a gnotobiotic system, Bs006 colonized the root surface of golden berry, inhibited the growth of Foph, and produced CLPs. Individual application of Bs006 and supernatant protected the plants from Foph infections by 37 and 53%, respectively. Meanwhile, fengycins reduced the disease progress by 39%. These results suggest further studies to select an optimum combination of Bs006 and supernatant or CLPs which might be a good option as biofungicide against Foph.

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