Table 2 List of the investigated Paramecium bursaria strains including information on the respective syngen, origin, the green algal endosymbiont and accession number (new accessions highlighted in bold).

PB-19

R1 (B6)

Poland: Biebrza National Park

MT231330

Cvar

[1]

CCAP 1660/11

R1 (B6)

England: Cambridge, Cavendish Pond

MT231331

Mcon

[1]

CCAP 1660/12

R1 (B6)

England: Cambridge, Cavendish Pond

MT231332

Mcon

[1], [2]

SAG 27.96

R1 (B6)

Germany: Göttingen, pond in Old Botanical Garden

MT231333

Mcon

[1], [2], [3]

CCAP 1660/46

R1 (B6)

Germany: Göttingen, pond in Old Botanical Garden

OK318475

Mcon

[1]

CCAP 1660/47

R1 (B6)

Germany: Göttingen, pond in Old Botanical Garden

OK318476

Mcon

[1]

CCAP 1660/37

R1 (B6)

Germany: Pond near Minister

OK318477

Mcon

[1]

CCAP 1660/38

R1 (B6)

Germany: Pond near Minster

OK318478

Mcon

[1]

PB-25

R1 (B6)

Austria: Lake Mondsee

OK318479

Mcon

[1]

CCAP 1660/1B

R1 (B6)

England: Cambridgeshire, coprolite pits Haslingfield

OK318480

Mcon

[1]

CCAP 1660/13

R1 (B6)

England: Cambridge, Cavendish Pond

OK318475

Mcon

[1]

CCAP 1660/39

R2 (B4)

Germany: Lake Seeburg near Gottingen

MT231334

Cvar

[1]

CCAP 1660/16

R2 (B4)

Scotland: Loch Inverawe, Inverawe

MT231335

Mcon

[1]

CCAP 1660/18

R2 (B4)

Scotland: Loch Lily, Inverawe

MT231336

Mcon

[1]

CCAP 1660/20

R2 (B4)

Scotland: Loch Lily, Inverawe

MT231337

Mcon

[1]

PB-27

R2 (B4)

Austria: Lake Neusiedl

OK318482

unknown

–

PB-28

R2 (B4)

Austria: Lake Neusiedl

OK318483

unknown

–

CCAP 1660/17

R2 (B4)

Scotland: Loch Inverawe, Inverawe

OK318484

Mcon

[1]

CCAP 1660/19

R2 (B4)

Scotland: Loch Lily, Inverawe

OK318485

Mcon

[1]

CCAP 1660/34

R2 (B4)

Switzerland: small pond near Zurich

OK318486

Mcon

[1]

CCAP 1660/36

R2 (B4)

Austria: Lake Piburg

OK318487

Mcon

[1], [2], [3]

PB-26

R2 (B4)

England: Pond near Manchester

OK318488

Mcon

[1]

CCAP 1660/24

R2 (B4)

Scotland: Garden pond Kenmore Cottage, Bonawe

OK318489

Mcon

[1]

PB-2

R3 (B1)

USA: Massachusetts, Boston

MT231338

Cvar

[1]

CCAP 1660/28

R3 (B1)

Austria: Lake Piburg

MT231339

Cvar

[1], [2], [3]

CCAP 1660/29

R3 (B1)

Austria: Wildbichl

MT231340

Cvar

[1], [2]

CCAP 1660/21

R3 (B1)

Chile: Concepcion, artificial pond at University campus

MT231341

Cvar

[1]

CCAP 1660/22

R3 (B1)

Chile: Concepcion, artificial pond at University campus

MT231342

Cvar

[1]

CCAP 1660/23

R3 (B1)

Chile: Concepcion, artificial pond at University campus

MT231343

Cvar

[1]

CCAP 1660/31

R3 (B1)

Russia: Khabarovsk region, Amur river

MT231344

Cvar

[1]

CCAP 1660/32

R3 (B1)

Russia: Primorie, Kiparisovo

MT231345

Cvar

[1]

PB-17

R3 (B1)

Japan

OK318490

Cvar

[1]

CCAP 1660/26

R3 (B1)

Japan

OK318491

Cvar

[1]

PB-15

R3 (B1)

Japan

OK318492

Cvar

[1]

CCAP 1660/35

R3 (B1)

Japan: Matsue-city Shimane prefecture

OK318493

Cvar

[1]

PB-16

R3 (B1)

Japan

OK318494

Cvar

[1]

CCAP 1660/27

R3 (B1)

Japan

OK318495

Cvar

[1]

PB-11

R3 (B1)

Russia: St. Petersburg

OK318496

Cvar

[1]

PB-13

R3 (B1)

Italy: Pisa

OK318497

Cvar

[1]

MRBG1

R3 (B1)

Australia: Melbourne

AB219526 + AB252014

Cvar

[2]

So13

R3 (B1)

Japan: Nagano

AB206538 + AB252011

Cvar

[2]

OK1

R3 (B1)

Japan: Aich

AB206537 + AB252010

Cvar

[2]

Cs2

R3 (B1)

China: Shanghai

AB206543 + AB252013

Cvar

[2]

PB-1

R4 (B2)

USA: Massachusetts, Boston

MT231346

Unknown

–

CCAP 1660/25

R4 (B2)

USA: North Carolina, Burlington

MT231347

Cvar

[1], [2], [3]

CCAP 1660/33

R4 (B2)

Chile: Concepcion, Laguna Grande

OK318498

Mcon

[1]

CCAP 1660/10

R4 (B2)

England: Cambridge

AB252000 + AB252016

Cvul

[2]

CCAP 1660/30

R5

Russia: Astrakhan Nature Reserve

MT231348

Cvar

[1]