Pan-genome analysis of the 222 representative strains. (a) Pan-genome curve representing the number of shared (core) genes and unique (pan) genes counted as additional strains are added (x-axis). Strains were added in random order 10 times with differences displayed as shaded curves representing 95% confidence intervals. (b) Functional clusters of orthologous group (COG) annotation of the pan-genome. Abbreviations: A, RNA processing and modification; C, energy production and conversion; D, cell cycle control; E, amino acid metabolism and transport; F, nucleotide metabolism and transport; G, carbohydrate metabolism and transport; H, coenzyme metabolism; I, lipid metabolism; J, translation; K, transcription; L, replication and repair; M, cell wall/membrane/envelope biogenesis; N, cell motility; O, post-translational modification, protein turnover, chaperone functions; P, inorganic ion transport and metabolism; Q, secondary metabolites biosynthesis, transport and catabolism; T, signal transduction; U, intracellular trafficking and secretion; V, defence mechanisms; S, function unknown.