Species	Reference gene ID	Possible function	Papers / DOI
Arabidopsis	At1g64860	Essential protein.	No verified direct reference in this release
Arabidopsis	At5g13730	Sigma factors are initiation factors that promote the attachment of plastid-encoded RNA polymerase (PEP) to specific initiation sites and are then released.	Specific function of a plastid sigma factor for ndhF gene transcription.; 2005; DOI: 10.1093/nar/gki908; PMID: 16243785; https://pubmed.ncbi.nlm.nih.gov/16243785/
Rice	Os08g0163400	Sigma factors are initiation factors that promote the attachment of plastid-encoded RNA polymerase (PEP) to specific initiation sites and are then released (Probable).	The plastid sigma factor SIG1 maintains photosystem I activity via regulated expression of the psaA operon in rice chloroplasts.; 2007; DOI: 10.1111/j.1365-313x.2007.03216.x; PMID: 17651366; https://pubmed.ncbi.nlm.nih.gov/17651366/