Fig. 7
From: Population structure of an Antarctic aquatic cyanobacterium
Ca. Regnicoccus frigidus niche adaptation in Ace Lake. a Ca. Regnicoccus frigidus ecotypes with the capacity for (1) cyanide assimilation and/or (2) asparagine biosynthesis: yellow cylinder, ammonium transporter; blue cylinders, nitrate/nitrite transporters; pink cylinder, urea transporter. b Variability in the capacity of Ca. Regnicoccus frigidus populations to defend against or evade viruses: (3) BREX type 1 system, (4) type 1 RM system, (5) retron and (6) cell surface modification: green shapes, cell surface structures; grey shapes, modified cell surface structures; black virions, host-specific (specialist) viruses; light grey virions, generalist viruses. Genes found in all Ca. Regnicoccus frigidus (solid line arrows), Ca. Regnicoccus frigidus subpopulations (dashed line arrows) or all Ca. Regnicoccus frigidus plus a subpopulation containing additional genes (dotted line arrows). Genes identified in Ca. Regnicoccus frigidus subpopulations with depth-dependent coverage variation (dark red arrows): up, higher coverage in oxic zone; down, higher coverage in oxic-anoxic interface and anoxic zone; both up and down, coverage high in either zone due to distinct gene sequences in MAG-AL1 and MAG-AL2. Genes and substrates: Asn, asparagine; asnB, glutamine-hydrolysing asparagine synthetase; Asp, aspartate; BREX, bacteriophage exclusion; CN−, free cyanide; CO2, carbon dioxide; COOH− or R-COOH, carboxylic acid compounds; cynS, cyanate lyase; Gln, glutamine; Glu, glutamate; gogat, ferredoxin-glutamine oxoglutarate aminotransferase; gs, glutamine synthetase; HCO3−, bicarbonate; narB, ferredoxin-nitrate reductase; NH4+, ammonium; NO2−, nitrite; NO3−, nitrate; nirA, ferredoxin-nitrite reductase; nit1C, nitrilase from Nit1C gene cluster; OCN.−, cyanate; 2-OG, 2-oxoglutarate; R-CN, nitriles; ureABC, urease (alpha, beta, gamma subunits). Virions, viral and host DNA and degraded cell icons were taken from The Noun Project website [55]