Editing Cyanobacteria (section)

=== Cyanobionts ===
[[File:Leaf and root colonization by cyanobacteria.jpg|thumb|upright=2|right| {{center|'''Symbiosis with land plants'''{{hsp}}<ref name=Lee2021>{{cite journal | vauthors = Lee SM, Ryu CM | title = Algae as New Kids in the Beneficial Plant Microbiome | journal = Frontiers in Plant Science | volume = 12 | pages = 599742 | date = 4 Feb 2021 | pmid = 33613596 | pmc = 7889962 | doi = 10.3389/fpls.2021.599742 | publisher = Frontiers Media SA | doi-access = free | bibcode = 2021FrPS...1299742L }} {{Creative Commons text attribution notice|cc=by4|from this source=yes}}</ref><br />Leaf and root colonization by cyanobacteria}} (1) Cyanobacteria enter the leaf tissue through the [[stomata]] and colonize the intercellular space, forming a cyanobacterial loop.<br /> (2) On the root surface, cyanobacteria exhibit two types of colonization pattern; in the [[root hair]], filaments of ''[[Anabaena]]'' and ''[[Nostoc]]'' species form loose colonies, and in the restricted zone on the root surface, specific ''Nostoc'' species form cyanobacterial colonies.<br /> (3) Co-inoculation with [[2,4-Dichlorophenoxyacetic acid|2,4-D]] and ''Nostoc'' spp. increases para-nodule formation and nitrogen fixation. A large number of ''Nostoc'' spp. isolates colonize the root [[endosphere]] and form para-nodules.<ref name=Lee2021 />]]
{{main|Cyanobiont}}

Some cyanobacteria, the so-called [[cyanobiont]]s (cyanobacterial symbionts), have a [[symbiotic]] relationship with other organisms, both unicellular and multicellular.<ref name=Kim2020 /> As illustrated on the right, there are many examples of cyanobacteria interacting [[symbiotically]] with [[land plant]]s.<ref>{{cite journal |doi=10.1046/j.1469-8137.1999.00352.x |title=Colonization of wheatpara-nodules by the N2-fixing cyanobacterium ''Nostocsp''. Strain 2S9B |year=1999 | vauthors = Gantar M, Elhai J |journal=[[New Phytologist]] |volume=141 |issue=3 |pages=373–379 |doi-access=free}}</ref><ref>{{cite journal |doi=10.1007/s003740000243 |title=Mechanical damage of roots provides enhanced colonization of the wheat endorhizosphere by the dinitrogen-fixing cyanobacterium Nostoc sp. Strain 2S9B |year=2000 | vauthors = Gantar M |journal=Biology and Fertility of Soils |volume=32 |issue=3 |pages=250–255 |bibcode=2000BioFS..32..250G }}</ref><ref name=Treves2016>{{cite journal | vauthors = Treves H, Raanan H, Kedem I, Murik O, Keren N, Zer H, Berkowicz SM, Giordano M, Norici A, Shotland Y, Ohad I, Kaplan A | display-authors = 6 | title = The mechanisms whereby the green alga Chlorella ohadii, isolated from desert soil crust, exhibits unparalleled photodamage resistance | journal = The New Phytologist | volume = 210 | issue = 4 | pages = 1229–1243 | date = June 2016 | pmid = 26853530 | doi = 10.1111/nph.13870 | doi-access = free | bibcode = 2016NewPh.210.1229T }}</ref><ref>{{cite journal | vauthors = Zhu H, Li S, Hu Z, Liu G | title = Molecular characterization of eukaryotic algal communities in the tropical phyllosphere based on real-time sequencing of the 18S rDNA gene | journal = BMC Plant Biology | volume = 18 | issue = 1 | pages = 365 | date = December 2018 | pmid = 30563464 | pmc = 6299628 | doi = 10.1186/s12870-018-1588-7 | doi-access = free | bibcode = 2018BMCPB..18..365Z }}</ref> Cyanobacteria can enter the plant through the [[stomata]] and colonize the intercellular space, forming loops and intracellular coils.<ref>{{cite journal |doi=10.1016/j.revpalbo.2008.06.006 |title=Endophytic cyanobacteria in a 400-million-yr-old land plant: A scenario for the origin of a symbiosis? |year=2009 | vauthors = Krings M, Hass H, Kerp H, Taylor TN, Agerer R, Dotzler N |journal=[[Review of Palaeobotany and Palynology]] |volume=153 |issue=1–2 |pages=62–69|bibcode=2009RPaPa.153...62K }}</ref> ''[[Anabaena]]'' spp. colonize the roots of wheat and cotton plants.<ref>{{cite journal | vauthors = Karthikeyan N, Prasanna R, Sood A, Jaiswal P, Nayak S, Kaushik BD | title = Physiological characterization and electron microscopic investigation of cyanobacteria associated with wheat rhizosphere | journal = Folia Microbiologica | volume = 54 | issue = 1 | pages = 43–51 | year = 2009 | pmid = 19330544 | doi = 10.1007/s12223-009-0007-8 }}</ref><ref name=Babu2015>{{cite journal |doi=10.1007/s10811-014-0322-6 |title=Analysing the colonisation of inoculated cyanobacteria in wheat plants using biochemical and molecular tools |year=2015 | vauthors = Babu S, Prasanna R, Bidyarani N, Singh R |journal=Journal of Applied Phycology |volume=27 |issue=1 |pages=327–338 |bibcode=2015JAPco..27..327B }}</ref><ref name=Bidyarani2015>{{cite journal | vauthors = Bidyarani N, Prasanna R, Chawla G, Babu S, Singh R | title = Deciphering the factors associated with the colonization of rice plants by cyanobacteria | journal = Journal of Basic Microbiology | volume = 55 | issue = 4 | pages = 407–419 | date = April 2015 | pmid = 25515189 | doi = 10.1002/jobm.201400591 }}</ref> ''[[Calothrix]]'' sp. has also been found on the root system of wheat.<ref name=Babu2015 /><ref name=Bidyarani2015 /> [[Monocot]]s, such as wheat and rice, have been colonised by ''[[Nostoc]]'' spp.,<ref name=Gantar1991>{{cite journal |doi=10.1111/j.1469-8137.1991.tb00031.x |title=Colonization of wheat (Triticum vulgare L.) by N2-fixing cyanobacteria: II. An ultrastructural study |year=1991 | vauthors = Gantar M, Kerby NW, Rowell P |journal=[[New Phytologist]] |volume=118 |issue=3 |pages=485–492 |doi-access=free|bibcode=1991NewPh.118..485G }}</ref><ref>{{cite journal |doi=10.1007/s11104-010-0488-x |title=Association of non-heterocystous cyanobacteria with crop plants |year=2010 | vauthors = Ahmed M, Stal LJ, Hasnain S |journal=[[Plant and Soil]] |volume=336 |issue=1–2 |pages=363–375 |bibcode=2010PlSoi.336..363A |url=http://dare.uva.nl/personal/pure/en/publications/association-of-nonheterocystous-cyanobacteria-with-crop-plants(a90f9b12-6bd1-47cc-87c4-389ab649d969).html }}</ref><ref>{{cite journal | vauthors = Hussain A, Hamayun M, Shah ST | title = Root colonization and phytostimulation by phytohormones producing entophytic Nostoc sp. AH-12 | journal = Current Microbiology | volume = 67 | issue = 5 | pages = 624–630 | date = November 2013 | pmid = 23794014 | doi = 10.1007/s00284-013-0408-4 }}</ref><ref>{{cite journal | vauthors = Hussain A, Shah ST, Rahman H, Irshad M, Iqbal A | title = Effect of IAA on in vitro growth and colonization of Nostoc in plant roots | journal = Frontiers in Plant Science | volume = 6 | pages = 46 | year = 2015 | pmid = 25699072 | pmc = 4318279 | doi = 10.3389/fpls.2015.00046 | doi-access = free | bibcode = 2015FrPS....6...46H }}</ref> In 1991, Ganther and others isolated diverse [[heterocystous]] nitrogen-fixing cyanobacteria, including ''Nostoc'', ''Anabaena'' and ''[[Cylindrospermum]]'', from plant root and soil. Assessment of wheat seedling roots revealed two types of association patterns: loose colonization of root hair by ''Anabaena'' and tight colonization of the root surface within a restricted zone by ''Nostoc''.<ref name=Gantar1991 /><ref name=Lee2021 />

[[File:Cyanobacterial symbionts of Ornithocercus dinoflagellate 2.png|thumb|upright=2|left| {{center|'''Cyanobionts of ''Ornithocercus'' dinoflagellates'''{{hsp}}<ref name=Kim2020>{{cite journal | vauthors = Kim M, Choi DH, Park MG | title = Cyanobiont genetic diversity and host specificity of cyanobiont-bearing dinoflagellate Ornithocercus in temperate coastal waters | journal = Scientific Reports | volume = 11 | issue = 1 | pages = 9458 | date = May 2021 | pmid = 33947914 | pmc = 8097063 | doi = 10.1038/s41598-021-89072-z | bibcode = 2021NatSR..11.9458K }} {{Creative Commons text attribution notice|cc=by4|from this source=yes}}</ref>}} Live cyanobionts (cyanobacterial symbionts) belonging to ''[[Ornithocercus]]'' [[dinoflagellate]] host consortium<br />(a) ''O. magnificus'' with numerous cyanobionts present in the upper and lower girdle lists (black arrowheads) of the cingulum termed the symbiotic chamber.<br />(b) ''O. steinii'' with numerous cyanobionts inhabiting the symbiotic chamber.<br />(c) Enlargement of the area in (b) showing two cyanobionts that are being divided by binary transverse fission (white arrows).]]

[[File:Cyanobacteria in symbiosis with a diatom.png|thumb|upright=1|right| {{center|[[Epiphytic]] ''[[Calothrix]] ''cyanobacteria (arrows) in symbiosis with a ''[[Chaetoceros]]'' diatom. Scale bar 50 μm.}}]]

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The relationships between [[cyanobiont]]s (cyanobacterial symbionts) and protistan hosts are particularly noteworthy, as some nitrogen-fixing cyanobacteria ([[diazotroph]]s) play an important role in [[Marine primary production|primary production]], especially in nitrogen-limited [[oligotrophic]] oceans.<ref>{{cite journal |doi=10.1126/science.276.5316.1221 |title=Trichodesmium, a Globally Significant Marine Cyanobacterium |year=1997 | vauthors = Capone DG |journal=Science |volume=276 |issue=5316 |pages=1221–1229}}</ref><ref>{{cite journal | vauthors = Falkowski PG, Barber RT, Smetacek V | title = Biogeochemical Controls and Feedbacks on Ocean Primary Production | journal = Science | volume = 281 | issue = 5374 | pages = 200–207 | date = July 1998 | pmid = 9660741 | doi = 10.1126/science.281.5374.200 }}</ref><ref>{{cite journal |doi=10.4319/lo.2007.52.4.1293 |title=CO2 control of Trichodesmium N2 fixation, photosynthesis, growth rates, and elemental ratios: Implications for past, present, and future ocean biogeochemistry |year=2007 | vauthors = Hutchins DA, Fu FX, Zhang Y, Warner ME, Feng Y, Portune K, Bernhardt PW, Mulholland MR |author-link8=Margaret Mulholland |journal=[[Limnology and Oceanography]] |volume=52 |issue=4 |pages=1293–1304 |bibcode=2007LimOc..52.1293H |doi-access=free }}</ref> Cyanobacteria, mostly [[pico-]]sized ''[[Synechococcus]]'' and ''[[Prochlorococcus]]'', are ubiquitously distributed and are the most abundant photosynthetic organisms on Earth, accounting for a quarter of all carbon fixed in marine ecosystems.<ref name="Present and future global distribut"/><ref>{{cite journal | vauthors = Huang S, Wilhelm SW, Harvey HR, Taylor K, Jiao N, Chen F | title = Novel lineages of Prochlorococcus and Synechococcus in the global oceans | journal = The ISME Journal | volume = 6 | issue = 2 | pages = 285–297 | date = February 2012 | pmid = 21955990 | pmc = 3260499 | doi = 10.1038/ismej.2011.106 | bibcode = 2012ISMEJ...6..285H }}</ref><ref name="Partensky-1999"/> In contrast to free-living marine cyanobacteria, some cyanobionts are known to be responsible for nitrogen fixation rather than carbon fixation in the host.<ref>{{cite book |doi=10.1201/b13853 |title=Stress Biology of Cyanobacteria |date=2013 |publisher=CRC Press |isbn=978-0-429-10135-9 |editor-last1=Srivastava |editor-last2=Rai |editor-last3=Neilan |editor-first1=Ashish Kumar |editor-first2=Amar Nath |editor-first3=Brett A. }}{{pn|date=February 2025}}</ref><ref>{{cite journal | vauthors = Zehr JP, Bench SR, Carter BJ, Hewson I, Niazi F, Shi T, Tripp HJ, Affourtit JP | display-authors = 6 | title = Globally distributed uncultivated oceanic N2-fixing cyanobacteria lack oxygenic photosystem II | journal = Science | volume = 322 | issue = 5904 | pages = 1110–1112 | date = November 2008 | pmid = 19008448 | doi = 10.1126/science.1165340 | bibcode = 2008Sci...322.1110Z }}</ref> However, the physiological functions of most cyanobionts remain unknown. Cyanobionts have been found in numerous protist groups, including [[dinoflagellate]]s, [[tintinnid]]s, [[radiolarian]]s, [[amoebae]], [[diatom]]s, and [[haptophyte]]s.<ref>{{cite book |doi=10.1007/978-4-431-55130-0_19 |chapter=Photosymbiosis in Marine Planktonic Protists |title=Marine Protists |year=2015 | vauthors = Decelle J, Colin S, Foster RA |pages=465–500 |publisher=Springer |location=Tokyo |isbn=978-4-431-55129-4}}</ref><ref>{{cite journal | vauthors = Foster RA, Zehr JP | title = Diversity, Genomics, and Distribution of Phytoplankton-Cyanobacterium Single-Cell Symbiotic Associations | journal = Annual Review of Microbiology | volume = 73 | pages = 435–456 | date = September 2019 | issue = 1 | pmid = 31500535 | doi = 10.1146/annurev-micro-090817-062650 }}</ref> Among these cyanobionts, little is known regarding the nature (e.g., genetic diversity, host or cyanobiont specificity, and cyanobiont seasonality) of the symbiosis involved, particularly in relation to dinoflagellate host.<ref name=Kim2020 />

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