Growth assays on Trichoderma spent media
The effect of Trichoderma spp. spent media on S. melilotistrains was tested by monitoring bacterial growth of inocula on a 96-well microplate at 30°C for 72 hours with a microplate reader (Tecan Infinite 200 PRO, Tecan, Switzerland). Spent media obtained from each fungal species at 1, 2, and 3 weeks were added to inocula grown in TY liquid medium after normalization with the fungal biomass. Relative biomasses were calculated to the minimum dry-weight pellet. In each well a final concentration of 50% of SM was present. For each strain-spent medium combination, 3 independent cultures were set up and the growth inhibition index was calculated after 72h as: 1- OD600trt/OD600 ctr, where trt are treated and ctr the control samples.