FIG 5.

Functional verifications of sialic acid catabolic and griseobactin biosynthetic gene clusters. (A) The ability of representative free-living strains and insect-associated strains to utilize sialic acid as a sole carbon source. Strains were cultured for 5 days at 28°C on basal mineral salt medium agar plates supplemented with 1% N-acetylneuraminic acid or 1% glucose as a sole carbon source. (B) Arnow’s test of catechol-type siderophore production by representative insect-associated strains and free-living strains. The presence of a red color in the solution was recorded as a positive test for catechol.