Editing Plastid (section)

{{Short description|Plant cell organelles that perform photosynthesis and store starch}}
[[File:Plagiomnium affine laminazellen.jpeg|thumb|Plant cells with visible [[chloroplasts]]]]

A '''plastid''' is a [[membrane-bound organelle]] found in the [[Cell (biology)|cell]]s of [[plants]], [[algae]], and some other [[eukaryotic]] organisms. Plastids are considered to be intracellular [[endosymbiotic]] [[cyanobacteria]].<ref>{{cite book| vauthors = Sato N |pages= 75–102 |title=The Structure and Function of Plastids|volume=23| veditors = Wise RR, Hoober JK |publisher= Springer Netherlands|chapter=Origin and Evolution of Plastids: Genomic View on the Unification and Diversity of Plastids|isbn=978-1-4020-4060-3|doi=10.1007/978-1-4020-4061-0_4|series=Advances in Photosynthesis and Respiration|date=2007 }}</ref>

Examples of plastids include [[chloroplast]]s (used for [[photosynthesis]]); [[chromoplast]]s (used for synthesis and storage of pigments); [[leucoplast]]s (non-pigmented plastids, some of which can [[cellular differentiation|differentiate]]); and [[apicoplast]]s (non-photosynthetic plastids of [[apicomplexa]] derived from secondary endosymbiosis).

A permanent primary endosymbiosis event occurred about 1.5 billion years ago in the [[Archaeplastida]] clade{{mdash}}[[Embryophyte|land plants]], [[red algae]], [[green algae]] and [[glaucophyte]]s{{mdash}}probably with a [[cyanobiont]], a symbiotic cyanobacteria related to the genus ''[[Gloeomargarita lithophora|Gloeomargarita]]''.<ref>{{cite journal | vauthors = Moore KR, Magnabosco C, Momper L, Gold DA, Bosak T, Fournier GP | title = An Expanded Ribosomal Phylogeny of Cyanobacteria Supports a Deep Placement of Plastids | language = en | journal = Frontiers in Microbiology | volume = 10 | pages = 1612 | date = 2019 | pmid = 31354692 | pmc = 6640209 | doi = 10.3389/fmicb.2019.01612 | doi-access = free }}</ref><ref>{{Cite journal|last1=Vries|first1=Jan de|last2=Gould|first2=Sven B.|date=2018-01-15|title=The monoplastidic bottleneck in algae and plant evolution|url=https://jcs.biologists.org/content/131/2/jcs203414|journal=Journal of Cell Science|language=en|volume=131|issue=2|pages=jcs203414|doi=10.1242/jcs.203414|issn=0021-9533|pmid=28893840|doi-access=free}}</ref> Another primary endosymbiosis event occurred later, between 140 and 90 million years ago, in the photosynthetic plastids ''[[Paulinella]]'' [[amoeboid]]s of the cyanobacteria genera ''[[Prochlorococcus]]'' and ''[[Synechococcus]]'', or the "PS-clade".<ref name="Marin Nowack Glöckner Melkonian 2021 p.">{{cite journal|last1=Marin|first1=Birger|last2=Nowack|first2=Eva CM|last3=Glöckner|first3=Gernot|last4=Melkonian|first4=Michael|date=2007-06-05|title=The ancestor of the Paulinella chromatophore obtained a carboxysomal operon by horizontal gene transfer from a Nitrococcus-like γ-proteobacterium|journal=BMC Evolutionary Biology|volume=7|issue=1 |page=85|doi=10.1186/1471-2148-7-85|pmc=1904183|pmid=17550603|bibcode=2007BMCEE...7...85M |doi-access=free}}</ref><ref name="Ochoa de Alda-2014">{{Cite journal|last1=Ochoa de Alda|first1=Jesús A. G.|last2=Esteban|first2=Rocío|last3=Diago|first3=María Luz|last4=Houmard|first4=Jean|date=2014-01-29|title=The plastid ancestor originated among one of the major cyanobacterial lineages|journal=Nature Communications|language=en|volume=5|issue=1|pages=4937|doi=10.1038/ncomms5937|pmid=25222494|bibcode=2014NatCo...5.4937O|issn=2041-1723|doi-access=free}}</ref> [[Chloroplast#Secondary and tertiary endosymbiosis|Secondary and tertiary endosymbiosis]] events have also occurred in a wide variety of organisms; and some organisms developed the capacity to sequester ingested plastids{{mdash}}a process known as [[kleptoplasty]].

[[Andreas Franz Wilhelm Schimper|A. F. W. Schimper]]<ref>Schimper, A.F.W. (1882) "[https://www.biodiversitylibrary.org/page/55891946 Ueber die Gestalten der Stärkebildner und Farbkörper]" ''Botanisches Centralblatt'' 12(5): 175–178.</ref>{{efn|Sometimes [[Ernst Haeckel]] is credited to coin the term plastid, but his "plastid" includes nucleated cells and anucleated "cytodes"<ref>Haeckel, E. (1866) "[https://www.biodiversitylibrary.org/page/47207027 Morphologische Individuen erster Ordnung: Plastiden oder Plasmastücke]" in his ''Generelle Morphologie der Organismen'' Bd. 1, pp. 269–289</ref> and thus totally different concept from the plastid in modern literature.}} was the first to name, describe, and provide a clear definition of plastids, which possess a [[DNA#Base pairing|double-stranded DNA]] molecule that long has been thought of as circular in shape, like that of the [[circular prokaryote chromosome|circular chromosome]] of [[prokaryotic cells|''pro''karyotic cells]]{{mdash}}but now, perhaps not; (see [[chloroplast DNA#Molecular structure|"..a linear shape"]]). Plastids are sites for manufacturing and storing pigments and other important chemical compounds used by the cells of [[autotroph]]ic [[eukaryote]]s. Some contain [[biological pigments]] such as used in [[photosynthesis]] or which determine a cell's color. Plastids in organisms that have lost their photosynthetic properties are highly useful for manufacturing molecules like the [[Terpenoid|isoprenoids]].<ref>[https://www.the-scientist.com/news-opinion/picozoans-are-algae-after-all-study-68741 Picozoans Are Algae After All: Study | The Scientist Magazine®]</ref>