Reactome uses a three letter code for each species which are listed below.
Are the letter codes used by Reactome a standard?
If so is there a web page or download file that can validate the code and translate it to a common name?
HSA Homo sapiens
SSC Sus scrofa
GGA Gallus gallus
DME Drosophila melanogaster
RNO Rattus norvegicus
DDI Dictyostelium discoideum
MMU Mus musculus
ATH Arabidopsis thaliana
TGU Taeniopygia guttata
DRE Danio rerio
OSA Oryza sativa
BTA Bos taurus
XTR Xenopus tropicalis
CFA Canis familiaris
SCE Saccharomyces cerevisiae
PFA Plasmodium falciparum
CEL Caenorhabditis elegans
SPO Schizosaccharomyces pombe
ROT Rotavirus
FLU Influenza A virus
HCV Hepatitis C Virus
HBV Hepatitis B virus
HER Human herpesvirus 1
NME Neisseria meningitidis serogroup B
NME Neisseria meningitidis
CTR Chlamydia trachomatis
STY Salmonella typhimurium
STY Salmonella enterica
ECO Escherichia coli
OCU Oryctolagus cuniculus
XLA Xenopus laevis
CAE Cercopithecus aethiops
CGR Cricetulus griseus
HER Human herpesvirus 8
MCV Molluscum contagiosum virus subtype 1
MCV Molluscum contagiosum virus
HCY Human cytomegalovirus
HIV Human immunodeficiency virus 1
PCH Penicillium chrysogenum
TAE Triticum aestivum
VRA Vigna radiata var. radiata
VRA Vigna radiata
CFS Crithidia fasciculata
FCA Felis catus
AMA Arenicola marina
MGA Meleagris gallopavo
NGO Neisseria gonorrhoeae
SAU Staphylococcus aureus
MVI Measles virus
HAL Human alphaherpesvirus 2
EDIT
Not a complete answer as this only covers a subset of all organisms but at present better than nothing.
Using KEGG Organisms
https://www.genome.jp/kegg-bin/get_htext
Enter letter code, e.g. GGA
EDIT - After reading answer by conchoecia
The graph database schema for Reactome only has two labels that use the 3 letter code which is named abbreviation in the schema:
Species and ReferenceTherapeutic
Species has taxid (Taxon Identifier)
abbreviation taxId displayName
AMA 6344 Arenicola marina
ATH 3702 Arabidopsis thaliana
BAN 1392 Bacillus anthracis
BTA 9913 Bos taurus
CAE 9534 Cercopithecus aethiops
CAL 5476 Candida albicans
CBO 1491 Clostridium botulinum
CEL 6239 Caenorhabditis elegans
CFA 9615 Canis familiaris
CFS 5656 Crithidia fasciculata
CGR 10029 Cricetulus griseus
CPH 10703 Corynephage beta
CPO 10141 Cavia porcellus
CSB 60711 Chlorocebus sabaeus
CTE 1513 Clostridium tetani
CTR 813 Chlamydia trachomatis
CVI 10243 Cowpox virus
DDI 44689 Dictyostelium discoideum
DME 7227 Drosophila melanogaster
DRE 7955 Danio rerio
ECO 562 Escherichia coli
FCA 9685 Felis catus
FLU 11320 Influenza A virus
GGA 9031 Gallus gallus
HAL 10310 Human alphaherpesvirus 2
HAM 6706 Homarus americanus
HBV 10407 Hepatitis B virus
HCV 11103 Hepatitis C Virus
HCV 31649 Hepatitis C virus genotype 2a
HCV 31646 Hepatitis C virus subtype 1a
HCY 10359 Human cytomegalovirus
HER 10298 Human herpesvirus 1
HER 37296 Human herpesvirus 8
HGA 10376 Human gammaherpesvirus 4
HIV 11676 Human immunodeficiency virus 1
HPV 333760 Human papillomavirus type 16
HPV 337041 Alphapapillomavirus 9
HSA 9606 Homo sapiens
IBR 11120 Infectious bronchitis virus
LMO 1639 Listeria monocytogenes
LMO 1906951 Listeria monocytogenes serovar 1/2a
LPN 446 Legionella pneumophila
MCV 10280 Molluscum contagiosum virus subtype 1
MCV 10279 Molluscum contagiosum virus
MGA 9013 Meleagris gallopavo
MML 9544 Macaca mulatta
MMU 10090 Mus musculus
MTU 1773 Mycobacterium tuberculosis
MTU 83332 Mycobacterium tuberculosis H37Rv
MVI 11234 Measles virus
NGO 485 Neisseria gonorrhoeae
NME 491 Neisseria meningitidis serogroup B
NME 487 Neisseria meningitidis
OAR 9940 Ovis aries
OCU 9986 Oryctolagus cuniculus
OSA 4530 Oryza sativa
PCH 5076 Penicillium chrysogenum
PFA 5833 Plasmodium falciparum
RNO 10116 Rattus norvegicus
ROT 10912 Rotavirus
SAU 1280 Staphylococcus aureus
SCE 4932 Saccharomyces cerevisiae
SEV 11191 Sendai virus
SPO 4896 Schizosaccharomyces pombe
SSC 9823 Sus scrofa
STY 90371 Salmonella typhimurium
STY 28901 Salmonella enterica
TAE 4565 Triticum aestivum
TGO 5811 Toxoplasma gondii
TGU 59729 Taeniopygia guttata
VRA 3916 Vigna radiata var. radiata
VRA 157791 Vigna radiata
VVI 10245 Vaccinia virus
XLA 8355 Xenopus laevis
XTR 8364 Xenopus tropicalis
While ReferenceTherapeutic does not.
The species can be identified using the NCBI taxon identifier, e.g.
https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=6344
EDIT - After reading answer by user172818
Searching the file https://www.uniprot.org/docs/speclist.txt for 6344
AREMA E 6344: N=Arenicola marina
C=Lugworm
S=Lumbricus marinus
or using the URL: https://www.uniprot.org/taxonomy/6344
and with reference to
I think databases should stop inventing new species abbreviations.
The Wikipedia article on Lugworm shows the many Taxon identifiers in multiple databases.
