Table S1. Distribution of mannosylglycerate and biosynthetic genes.Organisms in which MG has been detected (bold style); organisms harbouring the biosynthetic genes (regular style); organisms in which both genes and MG have been found (underlined).

ARCHAEA
Euryarchaeota
Thermococcales (Pyrococcus yayanosii; Pyrococcus sp. NA2; Pyrococcussp. ST04; Pyrococcus abyssi;Pyrococcus furiosus (DSM 3638; COM1); Pyrococcus horikoshii;Thermococcus gammatolerans; Thermococcus sp. ES1; Thermococcus litoralis;Thermococcus stetteri;Thermococcus celer;Thermococcus sp. AM4; Thermococcus sibiricus; Thermococcus barophilus;Palaeococcus ferrophilus)
Methanobacteriales (Methanothermus fervidus)
Archaeoglobales (Archaeoglobus profundus;Archaeoglobus veneficus)
Crenarchaeota
Desulfurococcales (Aeropyrum camini;Aeropyrum pernix; Staphylothermus marinus; Staphylothermus hellenicus; Stetteria hydrogenophila)
Thaumarchaeota
Nitrososphaerales(Candidatus Nitrososphaera gargensis)
BACTERIA
Bacteroidetes (Rhodothermus marinus; Flexithrix dorotheae)
Verrucomicrobiales (Verrucomicrobiae bacteriumDG1235)
Dehalococcoidales(Dehalococcoides sp. VS; Dehalococcoides sp. BAV1; Dehalococcoides ethenogenes;Dehalococcoides mccartyi (DCMB5; BTF08; GY50); Dehalococcoides sp. CBDB1; Dehalogenimonas lykanthroporepellens)
Thermales (Thermus thermophilus (HB8; HB27; SG0.5JP17-16; JL-18; Marinithermus hydrothermalis)
Actinomycetales (Catelliglobosispora koreensis; Actinoplanes friuliensis; Actinoplanes globisporus; Actinoplanes sp. N902-109)
Rubrobacterales (Rubrobacter xylanophilus)
EUKARYOTA
Fungi
Sordaria macrospora; Neurospora crassa; Neurospora tetrasperma; Podospora anserina; Chaetomium thermophilum; Chaetomium globosum; Thielavia terrestris; Myceliophthora thermophila; Magnaporthe oryzae (Y34; P131); Gaeumannomyces graminis; Togninia minima; Eutypa lata; Colletotrichum gloeosporioides (Cg-14; Nara gc5); Colletotrichum orbiculare; Pyrenophora teres; Pyrenophora tritici-repentis; Phaeosphaeria nodorum; Leptosphaeria maculans
Early land plants
Physcomitrella patens; Selaginella moellendorffii
Red algae
Gigartinales (Chondrus crispus; Gigartinasp.; Ahnfeltiopsis flabelliformis;Ahnfeltiopsis leptophylla; Phyllophora pseudoceranoides; Schottera nicaeensis; Solieria chordalis; Hypneasp.; Kappaphycus alvarezii; Eucheuma denticulatum)
Porphyridiales (Erythrolobus coxiae; Erythrolobus australicus; Erythrolobus madagascarensis; Erythrolobus sp.;Porphyridium marinum; Porphyridium purpureum; Porphyridium cruentum;Timspurckia oligopyrenoides; Timspurckia multipyrenoidosa)
Gelidiales (Gelidium sp.)
Ceramiales (Acrothamnion preissii; Anotrichium sp.; Anotrichium furcellatum; Antithamnion densum; Antithamnion pectinatum; Antithamnion tenuissimum; Antithamnionella glandulifera; Balliella sp.; Centrocerassp.; Ceramium sp.; Ceramium boydenii; Caloglossa leprieurii; Crouania sp.; Dasyphila plumarioides; Gymnothamnion elegans; Haloplegma duperreyi; Pterothamnion pectinatum; Pterothamnion villosum; Pterothamnion yezoense; Griffithsia japonica;Griffithsia okiensis; Dasya iridescens; Dasya sinicola; Heterosiphonia gibbesii; Branchioglossum woodii; Claudea batanensis; Delesseria sanguinea; Martensia fragilis; Nitophyllum adhaerens; Phycodrys rubens; Phycodrys setchellii; Zellera tawallina; Melanamansia glomerata; Laurenciasp.; Murrayella periclados; Osmundaria fimbriata; Polysiphonia accuminata; Polysiphonia howei, Polysiphonia morrowii; Polysiphonia pacifica; Pterosiphonia bipinnata; Hypoglossum barbatum; Hypoglossum tenuifolium; Hypoglossum rhizophorum; Hypoglossum caloglossoides; Hypoglossum heterocystideum; Hypoglossum hypoglossoides; Bostrychiaradicosa; Bostrychiasimpliciuscula)
Rhodymeniales (Champia parvula)
Gracilariales (Gracilaria changii; Gracilariopsis lemaneiformis)
Stylonematales(Bangiopsis subsimplex)
Green algae
Desmidiales (Penium margaritaceum)
Klebsormidiales (Klebsormidium flaccidum)
Zygnematales (Spirogyra pratensis)
Coleochaetales (Chaetosphaeridium globosum)

Ref: Karsten et al. 2005; 2007; Yang et al. 2011; Santos et al., 2011; Bondu et al. 2007; Broderg et al. 1998; Collén et al. 2013; Eggert et al. 2007; West et al. 2013; Yang et al. 2010. NCBI and JGI databases.

Table S2. GenBank NCBI accession numbers of 16S/18S rRNA genes and of the enzymes (MGS, MPGS, GGS, GPGS) used to construct the phylogenetic trees.

16S/18S genes
Dehalococcoides (AF004928.2); Dehalogenimonas (NR_074337.1); Thiobacillus (AY034139.1); Hydrogenivirga (AM285299.1); Escherichia (EU014689.1); Halomonas (AY553075.1); Chromohalobacter (NR_074225.1); Synechococcus (CP000951.1); Prochlorococcus (BX548175.1); Truepera (NR_074381.1); Deinococcus (DQ883808.1); Clostridium (NR_037126.1); Bacillus (EF451042.1); Thermus (EU682501.1); Caloglossa (AF251514.1); Griffithsia (U32565.1); Physcomitrella (X80986.1); Selaginella (X83520.1); Dunaliella (AF506698.1); Blyttiomyces (DQ536491.1); Podospora (X54864.1); Nanoarchaeum (AE017199.1); Halococcus (X00662.1); Halobacterium (NR_074204.1); Natronococcus (CP003929.1); Methanohalophilus (NR_104736.1); Methanococcoides (NR_074242.1); Thermoplasma (NR_074223.1); Methanosphaera (NR_074323.1); Methanothermus (CP002278.1); Methanococcus (NR_074094.1); Archaeoglobus (AE000782.1); Thermococcus (NR_028216.1); Pyrococcus (NR_074375.1); Palaeococcus (NR_028149.1); Methanopyrus (NR_074539.1); Methanotorris (AB095167.1); Hyperthermus (NR_102938.1); Pyrolobus (NR_102985.1); Aeropyrum (NR_043417); Staphylothermus (NR_044909.1); Ignisphaera (NR_102869.1); Metallosphaera (NR_043410.1); Korarchaeum (NR_074112.1); Nitrosopumilus (NR_102913.1); Pyrobaculum (CP000561.1); Sulfolobus (CP001404.1); Acidianus (AB182498.1); Caldivirga (NR_102972.1); Aquifex (NR_075056.1); Persephonella (NR_027538.1); Thermovibrio (NR_028954.1); Thermotoga (AJ401021.1); Marinitoga (NR_027541.1); Petrotoga (NR_074401.1); Rubrobacter (NR_074552.1); Rhodothermus (NR_074728.1); Methanobacterium (HQ591420.1); Hydrogenophilus (EF368015.1); Mycobacterium (NR_074726.1); Streptomyces (AB184838.1); Marinithermus (NR_074587.1); Nitrososphaera (NR_102916.1); Flexithrix (AF039296.1); Actinoplanes (NR_104746.1); Magnaporthe (JQ747492.1); Togninia (DQ471011.1); Gaeumannomyces (FJ176801.1); Stetteria (NR_044913.1); Pyrenophora (U43459.1); Neurospora(AY046271.1); Colletotrichum (DQ916151.1); Myceliophthora (CP003008.1); Thielavia (CP003011.1); Chaetomium (AB048285.1); Sordaria (X69851.1); Phaeosphaeria (EU189211.1); Champia (EF190546.1); Pterosiphonia (JX828187.1); Polysiphonia (HM560654.1); Gigartinales (JQ780839.1); Chondrus (DQ317000.1); Schottera (U33137.1); Gelidium (DQ316994.1); Anotrichium (U32561.1); Antithamnion (AY643487.1); Murrayella (AF203887.1); Eutypa (DQ836896.1); Penium (AF115440.1); Klebsormidium (M95613.1); Spirogyra (JQ290275.1); Chaetosphaeridium (AJ250110.1); Verrucomicrobiae(GQ902877.1); Catelliglobosispora (NR_028758.1)
MGS/GGS proteins
MGS: Klebsormidium flaccidum (HO441134.1; HO452028.1); Spirogyra pratensis (GW597749.1; GW600025.1); Chaetosphaeridium globosum (HO382452.1; HO384207.1); Griffithsia okiensis (GO255676.1; GO256052.1); Rhodothermus marinus DSM 4252 (YP_003290498.1); Physcomitrella patens (XP_001764114.1); Selaginella moellendorffii (XP_002978745.1); Chondrus crispus (XP_005716970.1); Griffithsia japonica (AAM93991.1; AAP80838.1); Caloglossa leprieurii (KJ627183); GGS: Persephonella marina (YP_002731347.1)
MPGS/GPGS proteins
MPGS: Actinoplanes friuliensis (YP_008738683);Aeropyrum pernix (NP_147578);Archaeoglobus profundus (YP_003400326);Archaeoglobus veneficus (YP_004342045, YP_004341721);Candidatus Nitrososphaera gargensis (YP_006863297, YP_006862193);Catelliglobosispora koreensis (WP_020523296);Chaetomium globosum (XP_001221434);Chaetomium thermophilum (XP_006697487);Colletotrichum fioriniae (EXF77278);Colletotrichum gloeosporioides (EQB58062);Colletotrichum orbiculare (ENH77554);Dehalococcoides ethenogenes (YP_003330586);Dehalogenimonas lykanthroporepellens (YP_003758500);Eutypa lata (EMR62133);Flexithrix dorotheae (WP_020530588);Gaeumannomyces graminis (EJT77368);Leptosphaeria maculans XP_003834827);Magnaporthe oryzae (ELQ42360);Marinithermus hydrothermalis (YP_004366955);Methanothermus fervidus(YP_004004106);Myceliophthora thermophila (XP_003662495);Neurospora crassa (XP_963062);Palaeococcus ferrophilus (AAY44813);Phaeosphaeria nodorum (XP_001804959);Podospora anserina (XP_001905511);Pyrenophora teres (XP_003300055);Pyrenophora tritici-repentis (XP_001933837);Pyrococcus abyssi (NP_126908);Rhodothermus marinus (YP_003289792);Sordaria macrospora (XP_003350352);Staphylothermus marinus (YP_001040514);Thermus thermophilus (YP_004563);Thielavia terrestris (XP_003656082);Togninia minima (EOO03686);Verrucomicrobiae bacterium (WP_008097607); MPGS/GPGS: Rubrobacter xylanophilus (ACJ24528); GPGS: Methanococcoides burtonii DSM 6242YP_565452)

Ref: GenBank NCBI accession numbers of 16S/18S rRNA genes were retrieved from National Center for Biotechnology Information (NCBI) and SILVA (Pruesse et al. 2007).

Figure S1. The tunnels in the catalytic pocket of MPGS. A. Representation of the two tunnels connecting the catalytic pocket of TthMPGS to the surface of the enzyme. The protein regions are coloured in the same way as in Figure 3B. B. view of the Tunnel II entrance, showing the two flexible loops in the foreground. SP-, sugar pocket -face; SP-, sugar pocket -face. Figure prepared with PyMol ( and CAVER (

Figure S2. Conserved residues in NDP-sugar binding pocket.The protein backbone of TthMpgS (PDB 2WVL) is represented as a Ctube, the GDP-Man ligand and selected side chains drawn as sticks, and the metal ions and water molecule are displayed as spheres. The protein backbone and the side-chain carbon atoms are coloured in the same way as in Figure 3B.The dashed linesindicate the hydrogen bonds or electrostatic interactions established between protein side-chain atoms and the bound NDP-sugar and metal ion ligands. The residue labels are colored black for TthMPGS. The topologically equivalent residues in RmaMGS and RxyMPGS/GPGS are represented by red and green labels, respectively. Figure prepared with PyMol ( Adapted from (Gonçalves et al. 2010).

Figure S3. Crystallographic snapshots of key points in MPG dephosporylation. A. A PO3--like species (PDB 3ZW7) represents the first step of phosphoryl transfer via an Asp8 acid-assisted catalysis.B. The final products (PDB 3ZU6) after nucleophilic attack by a water molecule, enabled by the rotation of the MG hydroxymethyl group away from Asp8. Figure adapted from (Gonçalves et al. 2011).

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