Supplementary Material Table S1. Identity level of 16S rRNA genes in representatives of the genus Thiothrix,%. Т. nivea T.unzii А1Т T. lacustris T. T. Thiothrix sp. Thiothrix DSM 5205T BLT caldifontis fructosivorans RT sp.SSD2 G1T QT Thiothrix sp RT 100.0 93.0 97.9 95.9 96.1 96.3 94.9 Thiothrix sp SSD2 94.0 100.0 96.1 94.8 94.6 94.3 93.3 Т. nivea DSM 5205T 97.9 96.1 100.0 94.6 95.1 95.1 94.3 T. unzii А1Т 95.9 94.8 95.41 100.0 95.4 95.5 95.7 T. lacustris BLT 96.1 94.6 94.6 94.8 100.0 98.7 98.6 T. caldifontis G1T 96.3 94.3 95.1 95.5 98.7 100.0 98.9 Table S2. Molecular characteristics of representatives of the genus Thiothrix. Species Т. nivea Thiothrix sp. T. lacustris BLT T. caldifontis G1T Thiothrix sp. RT DSM 5205T SSD2 % Average nucleotide identity (ANI) to: Т. nivea DSM 5205T 100.0 76.7 75.5 77.5 80.2 T. lacustris BLT 76.7 100.0 79.0 76.5 75.9 T. caldifontis G1T 75.5 79.0 100.0 76.7 74.8 Thiothrix sp. RT 77.5 76.5 76.7 100.0 76.7 Thiothrix sp. SSD2 80.2 75.9 74.8 76.7 100.0 % dDDH to: Т. nivea DSM 5205T 100.0 23.9 23.8 25.6 27.3 T. lacustris BLT 23.9 100.0 28.0 24.9 22.4 T. caldifontis G1T 23.8 28.0 100.0 30.2 22.7 Thiothrix sp. RT 25.6 24.9 30.2 100.0 24.9 Thiothrix sp. SSD2 27.3 22.4 22.7 24.9 100.0 Table S3. Genes encoding enzymes of metabolic pathways in Thiothrix sp. SSD2 and Thiothrix sp. RT. Thiothrix sp. RT Thiothrix sp. SSD2 Gene Predicted function RefSeq (GeneBank) ID of gene RefSeq (GeneBank) ID of gene Sulfur metabolism Sulfide quinone sqrA oxidoreductase SqrA (EC MBJ6611027.1 QLQ30307.1 1.8.5.4) Sulfide quinone sqrF oxidoreductase SqrF (EC MBJ6610553.1 QLQ32374.1 1.8.5.4) MBJ6609626.1 Sulfide dehydrogenase MBJ6609616.1 fccB (flavocytochrome c) QLQ32594.1 MBJ6610564.1 flavoprotein chain MBJ6610092.1 cytochrome c subunit of fccA flavocytochrome c sulfide MBJ6609617.1 QLQ32595.1 dehydrogenase Sulfide quinone sqrD oxidoreductase SqrD (EC — QLQ32934.1 1.8.5.4) sulfur oxidation c-type MBJ6609210.1 QLQ32948.1 soxA cytochrome SoxA (EC MBJ6612060.1 QLQ33792.1 1.8.2.3 ) thiosulfate oxidation carrier MBJ6611495.1 QLQ33790.1 soxZ complex protein SoxZ (EC MBJ6612061.1 QLQ33793.1 1.8.2.6 ) thiosulfate oxidation carrier MBJ6610773.1 QLQ33791.1 soxY protein SoxY (EC 1.8.2.6 ) MBJ6611927.1 QLQ33794.1 thiosulfohydrolase SoxB (EC soxB MBJ6610703.1 QLQ33787.1 3.1.6.20) sulfur oxidation c-type MBJ6609211.1 QLQ32949.1 soxX cytochrome SoxX (EC 1.8.2.3 ) MBJ6611926.1 QLQ33795.1 sulfite dehydrogenase WP_012971673.1 soeA (quinone) subunit SoeA (EC MBJ6610731.1 locus_tag="HZT40_19335" 1.8.5.6) sulfite dehydrogenase soeB (quinone) subunit SoeB (EC MBJ6610732.1 QLQ34300.1 1.8.5.6) sulfite dehydrogenase soeC (quinone) subunit SoeC (EC MBJ6610733.1 QLQ33396.1 1.8.5.6) adenylylsulfate reductase, aprA MBJ6611742.1 QLQ33717.1 subunit A (EC 1.8.4.10) adenylylsulfate reductase, aprB MBJ6611743.1 QLQ33716.1 subunit B (EC 1.8.4.10) sulfate adenylyltransferase sat MBJ6611744.1 QLQ33715.1 (EC 2.7.7.4) Dissimilatory sulfite dsrA reductase, alpha subunit (EC MBJ6609201.1 QLQ32927.1 1.8.99.5) Dissimilatory sulfite dsrB reductase, beta subunit (EC MBJ6609200.1 QLQ32926.1 1.8.99.5) tRNA 2-thiouridine dsrE synthesizing protein D (EC MBJ6609199.1 QLQ32925.1 2.8.1.-) tRNA 2-thiouridine dsrF synthesizing protein C (EC MBJ6609198.1 QLQ32924.1 2.8.1.-) tRNA 2-thiouridine dsrH synthesizing protein B (EC MBJ6609197.1 QLQ32923.1 2.8.1.-) tRNA 2-thiouridine MBJ6609196.1 QLQ32922.1 dsrC synthesizing protein E (EC MBJ6609205.1 QLQ30843.1 2.8.1.-) sulfite reduction-associated dsrM complex DsrMKJOP protein MBJ6609195.1 QLQ34178.1 DsrM sulfite reduction-associated dsrK complex DsrMKJOP protein MBJ6609194.1 QLQ32920.1 DsrK glutamate synthase (NADPH) dsrL small chain dsrL/ intracellular MBJ6609193.1 QLQ33191.1 sulfur oxidation protein DsrL Sulfite reduction-associated dsrJ complex DsrMKJOP MBJ6609192.1 QLQ32918.1 multiheme protein DsrJ sulfite reduction-associated dsrO complex DsrMKJOP iron- MBJ6609191.1 QLQ32917.1 sulfur protein DsrO sulfite reduction-associated dsrP complex DsrMKJOP protein MBJ6609190.1 QLQ32917.1 DsrP Cobyrinic acid A,C-diamide dsrN MBJ6611399.1 QLQ31889.1 synthase DsrN (EC 6.3.5.11) protein involved in sulfur dsrR MBJ6611400.1 — oxidation DsrR protein involved in sulfur dsrS MBJ6609394.1 QLQ31126.1 oxidation DsrS Nitrogen metabolism nitrate reductase alpha narG MBJ6612005.1 QLQ32018.1 subunit (EC 1.7.5.1) nitrate reductase beta subunit narH MBJ6612006.1 QLQ32018.1 (EC 1.7.5.1) nitrate reductase gamma narI MBJ6612008.1 QLQ34178.1 subunit (EC 1.7.5.1) nitrate reductase delta WP_020558834.1 narJ MBJ6612007.1 subunit (EC 1.7.5.1) locus_tag="HZT40_10965" nitrite reductase (NO- nirS — QLQ34181.1 forming) (EC 1.7.2.1) nitric oxide reductase subunit cnorB MBJ6610622.1 QLQ32042.1 B (EC 1.7.2.5 ) nitric oxide reductase subunit cnorC MBJ6610621.1 QLQ32043.1 C (EC 1.7.2.5 ) nitrite reductase (NADH) nirB MBJ6608915.1 QLQ33725.1 large subunit (EC 1.7.1.1) nitrite reductase (NADH) WP_002709036.1 nirD MBJ6608916.1 small subunit (EC 1.7.1.1) locus_tag="HZT40_21300" Nif-specific regulatory nifA MBJ6611989.1 QLQ31724.1 protein NifA cysteine desulfurase NifS (EC nifS MBJ6612022.1 QLQ31672.1 2.8.1.7) nitrogen fixation protein NifU nifU MBJ6612021.1 QLQ30621.1 and related proteins nifB nitrogen fixation protein NifB MBJ6612010.1 QLQ31713.1 nifX nitrogen fixation protein NifX MBJ6612158.1 QLQ32343.1 nitrogen fixation protein nifX2 MBJ6612160.1 QLQ32343.1 NifX2 nitrogen fixation protein nifB2 — QLQ31713.1 NifB2 nitrogen fixation-related nifY MBJ6611864.1 — protein, gamma subunit nitrogenase molybdenum- nifE cofactor synthesis protein — QLQ34086.1 NifE (EC 1.18.6.1) nitrogenase molybdenum- nNifN iron protein NifN (EC MBJ6612157.1 QLQ34087.1 1.18.6.1.) nifQ nitrogen fixation protein NifQ MBJ6612016.1 QLQ31677.1 homocitrate synthase NifV nifV MBJ6612029.1 QLQ30738.1 (EC 2.3.3.14) nitrogen fixation protein nifW MBJ6611969.1 QLQ30752.1 NifW nitrogen fixation protein nifM MBJ6611971.1 QLQ30754.1 NifM nitrogenase iron protein NifH nifH MBJ6611859.1 QLQ32348.1 (EC 1.18.6.1) nitrogenase molybdenum- nifD iron protein alpha chain (EC MBJ6611860.1 QLQ32347.1 1.18.6.1) nitrogenase molybdenum- nifK iron protein beta chain (EC MBJ6611861.1 QLQ32346.1 1.18.6.1) nifZ nitrogen fixation protein NifZ MBJ6611970.1 QLQ30753.1 nifT nitrogen fixation protein NifT MBJ6611862.1 QLQ32345.1 nifО NifО — QLQ31710.1 Phosphorus metabolism phosphate transport system phoU MBJ6611245.1 QLQ33978.1 protein PhoU Phosphate regulon sensor phoR MBJ6611243.1 QLQ32508.1 protein PhoR (EC 2.7.13.3) Phosphate regulon MBJ6610056.1 phoB transcriptional regulatory QLQ32507.1 MBJ6611244.1 protein PhoB (EC 2.7.13.3) phosphate transport system MBJ6610423.1 pstS QLQ31375.1 permease protein PstS MBJ6609608.1 phosphate transport system QLQ31376.1 pstA permease protein PstA (EC MBJ6611247.1 QLQ32506.1 7.3.2.1) phosphate transport system pstC permease protein PstC (EC MBJ6611248.1 QLQ32505.1 7.3.2.1) pstA; phosphate transport pstB system permease protein PstB MBJ6611246.1 QLQ31377.1 (EC 7.3.2.1) polyphosphate kinase ppk1 MBJ6610060.1 QLQ34227.1 (EC 2.7.4.1) Exopolyphosphatase (EC epp MBJ6611895.1 QLQ33092.1 3.6.1.11) Embden-Meyerhof (EM) pathway and Calvin-Benson-Bassham cycle MBJ6612047.1 glk Glucokinase (EC 2.7.1.2) QLQ32326.1 MBJ6610765.1 glucose-6-phosphate pgi MBJ6610764.1 QLQ33478.1 isomerase (EC 5.3.1.9) 6-phosphofructokinase (EC pfk MBJ6611738.1 QLQ33720.1 2.7.1.11) fructose-bisphosphate fbaA MBJ6611594.1 QLQ33878.1 aldolase class II (EC 4.1.2.13) triosephosphate isomerase tpiA MBJ6609013.1 QLQ32910.1 (EC 5.3.1.1) NAD-dependent MBJ6610017.1 gapA glyceraldehyde-3-phosphate QLQ33881.1 MBJ6611591.1 dehydrogenase (EC 1.2.1.12) Phosphoglycerate kinase (EC pgk MBJ6611592.1 QLQ33880.1 2.7.2.3) 2,3-bisphosphoglycerate- independent gpmI MBJ6608813.1 QLQ34313.1 phosphoglycerate mutase (EC 5.4.2.1) alpha-ribazole-5'-phosphate gpmB MBJ6610314.1 — phosphatase (EC 3.1.3.73) eno Enolase (EC 4.2.1.11) MBJ6611138.1 QLQ31148.1 QLQ33879.1 pyk Pyruvate kinase (EC 2.7.1.40) MBJ6611593.1 QLQ31383.1 Pyruvate dehydrogenase E1 MBJ6609898.1 QLQ33197.1 aceE component (EC 1.2.4.1) MBJ6611465.1 QLQ31452.1 Dihydrolipoamide acetyltransferase component MBJ6609899.1 pdhС QLQ33196.1 of pyruvate dehydrogenase MBJ6611466.1 complex (EC 2.3.1.12) Dihydrolipoamide QLQ33195.1 MBJ6609900.1 dehydrogenase of pyruvate QLQ31603.1 pdhD MBJ6610078.1 dehydrogenase complex (EC WP_019023766.1 MBJ6611467.1 1.8.1.4) locus_tag="HZT40_07365" Ribose 5-phosphate isomerase rpiA MBJ6610111.1 QLQ30286.1 A (EC 5.3.1.6) Ribulose-phosphate 3- rpe — QLQ31009.1 epimerase (EC 5.1.3.1) tktA Transketolase (EC 2.2.1.1) MBJ6611590.1 QLQ33882.1 Fructose-1,6-bisphosphatase, fbp MBJ6608875.1 present, but not annotated type I (EC 3.1.3.11) Ribulose bisphosphate MBJ6608981.1 carboxylase large chain (EC QLQ31332.1 rbcL MBJ6608742.1 4.1.1.39) Ribulose bisphosphate MBJ6608743.1 rbcS carboxylase small chain (EC QLQ31406.1 MBJ6608982.1 4.1.1.39) Phosphoribulokinase (EC prkB MBJ6608787.1 QLQ33508.1 2.7.1.19) Tricarboxylic acid (TCA) cycle, glyoxylate cycle and a way to anabolism from TCA Citrate synthase (si) (EC gltA MBJ6610081.1 QLQ31602.1 2.3.3.1) Aconitate hydratase 2 (EC acnB MBJ6610082.1 QLQ31601.1 4.2.1.3) Isocitrate dehydrogenase MBJ6611201.1 QLQ31348.1 idh (NADP) (EC 1.1.1.42) MBJ6609071.1 QLQ31637.1 2-oxoglutarate MBJ6610075.1 QLQ31177.1 sucA dehydrogenase E1 component MBJ6610863.1 QLQ31079.1 (EC 1.2.4.2) 2-oxoglutarate sucB dehydrogenase E2 complex MBJ6610077.1 QLQ31604.1 (EC 2.3.1.61) Succinyl-CoA ligase (ADP- WP_002706977.1 sucD forming) alpha chain (EC MBJ6610080.1 locus_tag="HZT40_08370"