cyanelle stroma

GO:0034060 · Membrane organelle · Subcellular region · Proposed

The space enclosed by the double membrane of a cyanelle. [GO:0034060]

Part of: cyanelle (GO:0009842)

Xrefs: uniprot.location:SL-0350 — Cyanelle stroma

Taxonomic distribution

NCBITaxon:38254 Glaucocystophyceae — COMMON: The cyanelle stroma is the internal matrix-filled compartment of glaucophyte cyanelles, excluding the thylakoid space. [uniprot.location:SL-0350 — Cyanelle stroma]
NCBITaxon:2762 Cyanophora paradoxa — COMMON: Cyanophora paradoxa cyanelles contain a stroma enclosed by the double envelope and traversed by internal thylakoid membranes. [DOI:10.1104/pp.71.2.409]

NCBITaxon:2762 Cyanophora paradoxa — Model glaucophyte used for ultrastructural studies of cyanelle envelope membranes, stroma, and thylakoids. [DOI:10.1104/pp.71.2.409]

The cyanelle stroma is the matrix-filled internal space enclosed by the cyanelle double envelope but excluding the thylakoid lumen.

Subject	Predicate	Object	Evidence
cyanelle stroma	is part of	cyanelle	`GO:0034060` GO:0034060 defines the cyanelle stroma as the space enclosed by the double membrane of a cyanelle. `uniprot.location:SL-0350` — Cyanelle stroma UniProt SL-0350 places the cyanelle stroma under the cyanelle subcellular location.
cyanelle inner membrane	bounds	cyanelle stroma	`GO:0036012` GO:0036012 defines the cyanelle inner membrane as the envelope bilayer that also faces the cyanelle stroma. `uniprot.location:SL-0480` — Cyanelle inner membrane UniProt SL-0480 describes the cyanelle inner membrane as separating the cyanelle stroma from the intermembrane space. `GO:0034060` GO:0034060 defines the cyanelle stroma as the space enclosed by the double membrane of a cyanelle.

INTERPRETATION (RESOLVED): Keep DNA, ribosomes, and temporary photosynthetic products out of the curated cyanelle stroma component list. UniProt SL-0350 describes DNA, ribosomes, and temporary photosynthesis products as contents of the matrix-filled stroma, not as generic source-neutral constituents that define the stroma compartment itself.

GO:0034060 Gene Ontology cellular-component term for cyanelle stroma.
GO:0009532 Gene Ontology cellular-component term for plastid stroma.
GO:0009842 Gene Ontology cellular-component term for cyanelle.
GO:0036012 Gene Ontology cellular-component term for the cyanelle inner membrane that bounds the stroma.
GO:0009843 Gene Ontology cellular-component term for cyanelle thylakoid, the internal membrane system that is separate from the stroma.
GO:0033114 Gene Ontology cellular-component term for cyanelle thylakoid lumen, the thylakoid-enclosed compartment excluded from the stroma.
GO:0033115 Gene Ontology cellular-component term for cyanelle thylakoid membrane.
uniprot.location:SL-0350 — Cyanelle stroma UniProt Subcellular Location entry SL-0350 maps Cyanelle stroma to GO:0034060, places it under plastid stroma and cyanelle, and describes it as the internal matrix-filled cyanelle space excluding the thylakoid space.
uniprot.location:SL-0480 — Cyanelle inner membrane UniProt Subcellular Location entry SL-0480 describes the cyanelle inner membrane as separating the cyanelle stroma from the intermembrane space.
DOI:10.1104/pp.71.2.409 Giddings, Wasmann and Staehelin 1983, Structure of the Thylakoids and Envelope Membranes of the Cyanelles of Cyanophora paradoxa, Plant Physiology.

2026-09-12T21:44:29Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-12T21:45:10Z codex · EXPANDED_RECORD — Added plastid-stroma parentage, cyanelle parthood, the UniProt SL-0350 xref, glaucophyte distribution, a nonmechanistic stroma topology graph, and a resolved interpretation that stromal DNA, ribosomes, and temporary photosynthetic products are contents rather than stroma components.
2026-09-12T21:50:59Z codex · ADDRESS_REVIEW — Addressed #710 by citing GO:0034060 on the inner-membrane boundary edge that points to the cyanelle stroma.
2026-09-21T10:04:10Z codex · REPLACED_UNREADABLE_EVIDENCE — Replaced unreadable Jackson et al. 2015 Glaucophyta evidence with reachable cyanelle evidence for #1231.