The First Screen included two sequential rounds of sorting (see Supporting Information Figure 4 for details). The GMDs were grown in induction medium, containing purified Ivyc, at 30 °C for 19 h, after which they were sieved over a 20 μm mesh and then
recovered from the sieve in fresh PBS. SYTOX Orange (Life Technologies, USA) was added to a final concentration of 100 NM just before sorting. GMD were sorted on an iCYT Synergy flow cytometer equipped with a 126 μm nozzle and laser lines of 488 and 561 nm for excitation of yEGFP and SYTOX Orange, respectively. Individual GMD isolated from high stringency plating sorts were placed on M. luteus indicator plates (0.5 mg mL−1 M. luteus, 10 μg/mL
E. coli Ivy, 0.5% dextrose, 1.5% galactose, 0.71% Difco YNB without
(NH4)2SO4, 0.25% (NH4)2SO4, 0.077% CSM−ura) and grown 4 days at
30 °C. Prevalent halo-forming colonies were selected for sequencing