FIG 4.

FeoA and FeoB from Shewanella oneidensis MR-1 (SoFeoA and SoFeoB) are necessary and sufficient to support iron uptake. (A) V. cholerae EPV6 cells were transformed simultaneously with different binary combinations of pSoFeoA, pSoFeoB, pSofeoAB, and the corresponding empty vectors (pACYC184 and pWKS30). (B) Control plate of LB agar supplemented with heme. V. cholerae EPV6 grows in this medium regardless of the presence or absence of a functional Feo system. (C) The same strains were plated onto nonsupplemented LB agar in the same order. Only the strains of V. cholerae EPV6 harboring both the SofeoA and SofeoB genes, either in a single vector or in separate vectors, grew in this medium.