plastid nucleoid

GO:0042646 · Nucleoid · Subcellular region · Proposed

A region of a plastid to which the DNA is confined. [GO:0042646]

Synonyms: Plastidic nucleoid

Part of: plastid stroma (GO:0009532)

Xrefs: uniprot.location:SL-0140 — Plastid nucleoid

Components

Component	Type	Part of / acts on	Grounding	Genes	Stoichiometry	Essential	Role
plastid DNA	Dna	part of	Reviewed label only (reviewed name; no accession asserted)			ESSENTIAL	Plastid genome DNA compacted with nucleoid-associated proteins into a non-membrane-bounded plastid-stromal nucleoid. `GO:0042646` GO:0042646 identifies the plastid nucleoid as the plastid region to which DNA is confined. `uniprot.location:SL-0140` — Plastid nucleoid UniProt SL-0140 defines the plastid nucleoid as a chromatin-dense, non-membrane-bounded plastidic pseudocompartment. `DOI:10.1093/gbe/evv233` Kobayashi et al. 2015 review chloroplast nucleoids as DNA-protein complexes that package plastid DNA in green plant plastids.

NCBITaxon:33090 Viridiplantae — COMMON: Green algae and land plants carry plastid genomes packaged into stromal nucleoids in their plastids. [DOI:10.1093/gbe/evv233]
NCBITaxon:3055 Chlamydomonas reinhardtii — COMMON: The Chlamydomonas reinhardtii chloroplast has HLP-containing nucleoids that package and organize its chloroplast DNA. [DOI:10.1093/mp/ssp083]

NCBITaxon:3055 Chlamydomonas reinhardtii — Green-algal model in which HLP knockdown connected a chloroplast-targeted HU-like protein to plastid DNA nucleoid organization and genome maintenance. [DOI:10.1093/mp/ssp083]

plastid genome organization — The plastid nucleoid confines, compacts and organizes plastid genome DNA within the plastid stroma.
- GO:0042646 GO defines the plastid nucleoid as the plastid region to which DNA is confined.
- DOI:10.1093/gbe/evv233 Kobayashi et al. 2015 review plastid DNA packaging in chloroplast nucleoids and the evolution of nucleoid organization in green plants.

Plastid genome DNA is packaged into non-membrane-bounded nucleoids in the plastid stroma.

Subject	Predicate	Object	Evidence
plastid stroma	contains	plastid nucleoid	`uniprot.location:SL-0140` — Plastid nucleoid UniProt SL-0140 places Plastid nucleoid under the Plastid stroma subcellular location.
plastid DNA	is packaged in	plastid nucleoid	`GO:0042646` GO:0042646 defines the plastid nucleoid as the plastid region to which DNA is confined.

CURATION_TODO (OPEN): Keep plastid nucleoid-associated proteins out of the generic record until an exact, source-neutral component family is curated. Plastid nucleoids are DNA-protein structures, but specific nucleoid-associated protein complements vary across plastid lineages and the Chlamydomonas HLP example already belongs on the exact chloroplast nucleoid child record. This generic plastid nucleoid record therefore curates plastid DNA and records the protein boundary as follow-up rather than guessing a broad InterPro, Pfam, or NCBIfam accession.

GO:0042646 Gene Ontology cellular-component term for plastid nucleoid.
GO:0009295 Gene Ontology cellular-component term for nucleoid.
GO:0009532 Gene Ontology cellular-component term for plastid stroma, the matrix space that contains plastid nucleoids.
uniprot.location:SL-0140 — Plastid nucleoid UniProt Subcellular Location entry SL-0140 maps Plastid nucleoid to GO:0042646 and places it under Plastid stroma.
DOI:10.1093/gbe/evv233 Kobayashi et al. 2015, Eukaryotic Components Remodeled Chloroplast Nucleoid Organization during the Green Plant Evolution, Genome Biology and Evolution.
DOI:10.1093/mp/ssp083 Karcher et al. 2009, The Chlamydomonas Chloroplast HLP Protein Is Required for Nucleoid Organization and Genome Maintenance, Molecular Plant.

2026-09-13T22:04:45Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-13T22:05:33Z codex · EXPANDED_RECORD — Added nucleoid parentage, plastid-stroma parthood, the UniProt SL-0140 exact synonym and xref, a reviewed-label-only plastid DNA component, Viridiplantae and Chlamydomonas scope, plastid genome organization, a nonmechanistic DNA-packaging topology graph, and a component-grounding TODO.