Additional file 7. Principal component analysis score plots of Yersinia ruckeri strains. Grouping of biological replicates shows good reproducibility of technical replicates for each sample. The score plots show that strain SP-05 differs from the three strains under both normal and iron-limited conditions, which show minor protein differences to each other. (A) PCA score plot under normal condition, (B) PCA score plot under iron-limited condition.