Table S2. ORFs located within analyzed Psychrobacter plasmids.

ORFs located within plasmid pP12P1 of Psychrobacter sp. DAB_AL12 Coding Best BLAST hits ORF Orientation Protein Possible function region Percentage GenBank no. size (aa) Organism (bp) identity (aa) accession no. Psychrobacter 307- 74 1 ← 318 Initiator RepB protein cryohalolentis K5 YP_579255 1263 (164/221) (plasmid 1) 2068- 34 2 → 179 Hypothetical protein Pantoea vagans C9-1 YP_003930687 2607 (48/141) ORFs located within plasmid pP32BP1 of Psychrobacter sp. DAB_AL32B Coding Best BLAST hits ORF Orientation Protein Possible function region Percentage Coding region no. size (aa) Organism (bp) identity (aa) (bp) Psychrobacter sp. 320- Plasmid replicase 53 1 → 315 PRwf-1 YP_001274370 1267 (RepA) (178/337) (plasmid pRWF101) 1697- 58 Moraxella catarrhalis 2 → 55 YacA-like protein YP_003627349 1864 (30/52) RH4 Pseudomonas syringae 1856- Mobilization protein C 47 3 ← 89 pv. maculicola ES4326 YP_025711 2125 (MobC) (35/74) (plasmid pPMA4326C) Moraxella bovis 2324- Mobilization protein A 52 4 → 326 ATCC 10900 YP_003289296 3304 (MobA) (135/262) (plasmid pMbo4.6) 3301- 31 Acinetobacter lwoffii 5 → 183 Hypothetical protein ZP_06071142 3852 (35/113) SH145 3925- Hypothetical protein, 51 Moraxella catarrhalis 6 → 224 EGE16689 4599 Sel1 domain protein (68/134) 12P80B1 ORFs located within plasmid pP43BP1 of Psychrobacter sp. DAB_AL43B Coding Best BLAST hits ORF Orientation Protein Possible function region Percentage Coding region no. size (aa) Organism (bp) identity (aa) (bp) 286- 45 1 → 315 Initiator RepB protein Acinetobacter sp. SH024 ZP_06693793 1233 (138/309) 1281- 84 Psychrobacter arcticus 2 → 161 Hypothetical protein YP_264162 1766 (36/161) 273-4 1849- 3 ← 114 Hypothetical protein - No hits found - 2193 2374- Mobilization protein A 46 Psychrobacter sp. 4 ← 349 ZP_08462213 3423 (MobA) (175/379) 1501(2011) Psychrobacter sp. 3420- Mobilization protein C 59 5 ← 106 PRwf-1 YP_001274382 3740 (MobC) (57/97) (plasmid pRWF101) Psychrobacter sp. 3986- 36 6 → 134 Hypothetical protein PRwf-1 YP_001274369 4390 (40/111) (plasmid pRWF101) ORFs located within plasmid pP43BP2 of Psychrobacter sp. DAB_AL43B Coding Best BLAST hits ORF Orientation Protein Possible function region Percentage Coding region no. size (aa) Organism (bp) identity (aa) (bp) 498- 61 Acinetobacter johnsonii 1 → 315 Initiator RepB protein ZP_06064826 1445 (150/245) SH046 1612- 35 2 → 331 Hypothetical protein Nitrosomonas sp. AL212 YP_004294730 2607 (105/301) 3169- 3 → 93 Hypothetical protein - No hits found - 3450 Psychrobacter 3461- RelB-like antitoxin of 96 4 ← 67 cryohalolentis K5 YP_579251 3664 toxin-antitoxin module (51/53) (plasmid 1)

1 Psychrobacter 3729- 38 5 ← 109 Hypothetical protein cryohalolentis K5 YP_579252 4046 (38/100) (plasmid 1) 4504- Mobilization protein A 48 Acinetobacter baumannii 6 → 313 ACX70401 5445 (MobA) (135/279) 135040 ORFs located within plasmid pP43BP3 of Psychrobacter sp. DAB_AL43B Coding Best BLAST hits ORF Orientation Protein Possible function region Percentage Coding region no. size (aa) Organism (bp) identity (aa) (bp) 446- 57 1 → 330 Initiator RepB protein Acinetobacter sp. SH024 ZP_06693793 1438 (147/257) 1596- Hypothetical protein, 77 Psychrobacter 2 ← 182 YP_580604 2144 YebN family protein (141/182) cryohalolentis K5 2231- 100 Psychrobacter 3 → 110 Hypothetical protein YP_580606 2563 (110/110) cryohalolentis K5 2656- RelE-like antitoxin of 67 Cardiobacterium 4 ← 88 ZP_09445945 2922 toxin-antitoxin module (58/86) valvarum F0432 Psychrobacter 2909- RelB-like antitoxin of 67 5 ← 93 cryohalolentis K5 YP_579251 3190 toxin-antitoxin module (41/61) (plasmid 1) Psychrobacter 3281- 42 6 ← 91 Hypothetical protein cryohalolentis K5 YP_579252 3556 (36/86) (plasmid 1) 4014- Mobilization protein A 47 Acinetobacter baumannii 7 → 313 ACX70401 4955 (MobA) (132/279) 135040 ORFs located within plasmid pP43BP4 of Psychrobacter sp. DAB_AL43B Coding Best BLAST hits ORF Orientation Protein Possible function region Percentage Coding region no. size (aa) Organism (bp) identity (aa) (bp) Psychrobacter 454- Plasmid replicase 91 1 → 293 cryohalolentis K5 YP_579243 1335 (RepA) (267/293) (plasmid 1) 1520- 36 2 ← 103 Hypothetical protein Paenibacillus lactis 154 ZP_09002102 1831 (27/74) 1853- 55 Psychrobacter 3 ← 152 Hypothetical protein YP_581222 2311 (56/102) cryohalolentis K5 2425- 75 Psychrobacter arcticus 4 ← 155 Hypothetical protein YP_263495 2892 (117/157) 273-4 Pseudoalteromonas sp. 3187- Mobilization protein C 47 5 → 110 643A YP_001887741 3519 (MobC) (51/108) (plasmid pKW1) Pseudoalteromonas sp. 3509- Mobilization protein A 64 6 → 637 643A YP_001887742 5422 (MobA) (144/224) (plasmid pKW1) Pseudoalteromonas sp. 4221- 35 7 → 183 Hypothetical protein 643A YP_001887743 4772 (54/153) (plasmid pKW1) Pseudoalteromonas sp. 4776- 36 8 → 190 Hypothetical protein 643A YP_001887745 5348 (68/187) (plasmid pKW1) 5596- 9 → 284 Hypothetical protein 39 (64/163) Gramella forsetii KT0803 YP_862674 6450 ORFs located within plasmid pP60P1 of Psychrobacter sp. DAB_AL60 Coding Best BLAST hits ORF Orientation Protein Possible function region Percentage Coding region no. size (aa) Organism (bp) identity (aa) (bp) Psychrobacter 283- Plasmid replicase 90 1 → 293 cryohalolentis K5 YP_579243 1164 (RepA) (263/293) (plasmid 1) 1240- 2 ← 181 Hypothetical protein - No hits found - 1785

2 1836- 3 ← 132 Hypothetical protein - No hits found - 2234 Pseudoalteromonas sp. 2536- Mobilization protein C 46 4 → 110 643A YP_001887741 2868 (MobC) (50/108) (plasmid pKW1) Pseudoalteromonas sp. 2858- Mobilization protein A 66 5 → 637 643A YP_001887742 4771 (MobA) (138/209) (plasmid pKW1) Pseudoalteromonas sp. 3570- 32 6 → 183 Hypothetical protein 643A YP_001887743 4121 (49/153) (plasmid pKW1) Pseudoalteromonas sp. 4125- 36 7 → 191 Hypothetical protein 643A YP_001887745 4700 (68/187) (plasmid pKW1) 4959- 45 uncultured bacterium 8 → 158 Hypothetical protein ACN22658 5435 (72/160) clone BF11_C10 ORFs located within plasmid pP60P2 of Psychrobacter sp. DAB_AL60 Coding Best BLAST hits ORF Orientation Protein Possible function region Percentage Coding region no. size (aa) Organism (bp) identity (aa) (bp) Psychrobacter 344- 56 1 → 329 Initiator RepB protein cryohalolentis K5 YP_579255 1333 (161/290) (plasmid 1) 1801- 72 Psychrobacter 2 ← 63 Transposase YP_580194 1992 (39/54) cryohalolentis K5 2109- 71 3 ← 164 Hypothetical protein Psychrobacter sp. J466 ACY02902 2603 (119/168) Candidatus 2937- Hypothetical protein, 46 4 → 265 Amoebophilus asiaticus YP_001957952 3734 Sel1 domain protein (102/221) 5a2 4271- DNA (cytosine-5-)- 60 Marivirga tractuosa DSM 5 → 470 YP_004054233 5683 methyltransferase (255/424) 4126 5727- 47 Moraxella catarrhalis 6 ← 299 Hypothetical protein EGE16233 6626 (135/290) BC1 6883- Alkyl hydroperoxide 99 Psychrobacter arcticus 7 → 188 YP_265079 7449 reductase, subunit C (187/188) 273-4 8258- Hypothetical protein, 48 8 → 346 Neisseria sp. GT4A_CT1 ZP_08890114 9298 Sel1 domain protein (158/331) 9413- 32 Enhydrobacter 9 → 150 Hypothetical protein ZP_05621186 9865 (33/103) aerosaccus SK60 9909- 83 Acinetobacter baumannii 10 ← 206 Resolvase ZP_08433422 10529 (169/204) 6013150 10816- ABC transporter ATP- 31 Lactobacillus plantarum 11 → 344 YP_003064009 11850 binding protein (34/108) JDM1 11989- Mobilization protein C 36 Psychrobacter sp. 12 ← 171 ZP_08462219 12504 (MobC) (42/116) 1501(2011) 12792- Mobilization protein A 77 13 → 710 Psychrobacter sp. J466 ACY02904 14924 (MobA) (550/712) ORFs located within plasmid pP109bwP1 of Psychrobacter sp. DAB_AL109bw Coding Best BLAST hits ORF Orientation Protein Possible function region Percentage Coding region no. size (aa) Organism (bp) identity (aa) (bp) 218- Plasmid replicase 39 Moraxella catarrhalis 1 → 312 NP_957539 1156 (RepA) (113/293) (plasmid pEMCJH03) 1414- RelB-like antitoxin of 45 Desulfitobacterium 2 ← 54 YP_002460026 1578 addiction module (18/40) hafniense DCB-2 Pseudoalteromonas sp. 2239- Mobilization protein C 58 3 → 110 643A YP_001887741 2571 (MobC) (63/108) (plasmid pKW1) Pseudoalteromonas sp. 2561- Mobilization protein A 61 4 → 613 643A YP_001887742 4402 (MobA) (137/223) (plasmid pKW1)

3 Pseudoalteromonas sp. 3273- 35 5 → 183 Hypothetical protein 643A YP_001887743 3824 (53/153) (plasmid pKW1) Pseudoalteromonas sp. 3828- 35 6 → 172 Hypothetical protein 643A YP_001887745 4346 (60/173) (plasmid pKW1)

4