Fig. 2: Genome properties, gene transcription and proposed metabolism of the Candidatus Tectiglobus diatomicola symbiont.
From: Rhizobia–diatom symbiosis fixes missing nitrogen in the ocean
a, Circular representation of the Ca. T. diatomicola genome with 13 encoding contigs (grey), GC content (black) and the average transcription of protein-coding genes as transcripts per million (TPM) (blue; TPM values higher than 800 were cut off). Genes related to N2 fixation (orange), electron transport chain and ATP generation (blue) and the TCA cycle (red) are highlighted. CDS, coding sequence; comp., completeness; red., redundancy; tmRNA, transfer-messenger RNA. b, Schematic of the proposed metabolic potential of Ca. T. diatomicola (white) and its interactions with Haslea (grey and green), indicating the transfer of fixed nitrogen from the N2-fixing symbiont in return for diatom-derived C4-dicarboxylic acids, such as succinate. Proteins and corresponding gene names are: Complex I (NADH–quinone oxidoreductase, nuoBNEF), Complex II (succinate dehydrogenase, sdhABCD), Complex III (cytochrome b/c1, fbcH_1/2, fbcF), Complex IV (cbb3-type oxidase, ccoNOP), Complex V (ATP synthase, atpABDEGF); fumarate hydratase (fumC); aconitate hydratase (acnB); 2-oxoglutarate dehydrogenase (sucAB, lpd); succinyl-CoA synthetase (sucCD); malate dehydrogenase (mdh); isocitrate dehydrogenase (icd); citrate synthase (gltA); nitrogenase (nifHDK) and its ancillary proteins (nifAENBMQSTUVWXZ) and ferredoxins (fdxABN); rnf complex (rnfBCD); dicarboxylic acid transporter (dctPQM); pyruvate dehydrogenase (aceEF, lpd); pyruvate kinase (pyk); malic enzyme (maeB); and phosphoenolpyruvate carboxykinase (pckA). 2-OG, 2-oxoglutarate; PEP, phosphoenolpyruvate.
