Colony morphology of Y . ruckeri strains grown on TSA-SDS containing Coomassie brilliant blue dye showing the HSF
( Y . ruckeri 150 parental strain, left) and HSF
(mutant obtained after the screening of a Y . ruckeri 150 Tn5 Km2 library, right) phenotypes. Aliquots of 5 μl from early stationary phase cultures of the parental and mutant strains were spotted onto TSA-SDS Coomassie brilliant blue medium. After 48 h of incubation at 28°C colonies were photographed. Creamy white colony (HSF+) contrasts with the blue colony (HSF-) phenotype.