Editing Gunnera (section)

==Cyanobacterial symbiosis==
At least some species of ''Gunnera'' host [[Endosymbiont|endosymbiotic]] [[cyanobacteria]] such as ''[[Nostoc punctiforme]]''. The cyanobacteria provide [[Nitrogen fixation#Other plant symbionts|fixed nitrogen]] to the plant, while the plant provides fixed carbon to the microbe.<ref name="WFMJ">{{cite journal | vauthors = Wong FC, Meeks JC | title = Establishment of a functional symbiosis between the cyanobacterium Nostoc punctiforme and the bryophyte Anthoceros punctatus requires genes involved in nitrogen control and initiation of heterocyst differentiation | journal = Microbiology | volume = 148 | issue = Pt 1 | pages = 315–323 | date = January 2002 | pmid = 11782524 | doi = 10.1099/00221287-148-1-315 | doi-access = free }}</ref> The bacteria enter the plant via glands found at the base of each leaf stalk<ref name="Bergman">{{cite journal | vauthors = Bergman B, Johansson C, Söderbäck E | title = The ''Nostoc''-''Gunnera'' symbiosis | journal = The New Phytologist | volume = 122 | issue = 3 | pages = 379–400 | date = November 1992 | pmid = 33874210 | doi = 10.1111/j.1469-8137.1992.tb00067.x | doi-access = free }}</ref> and initiate an intracellular symbiosis which is thought to provide the plant with fixed nitrogen in return for fixed carbon for the bacterium. The Nostoc-filled symbiotic tissue makes up just a small portion of the plant's total biomass. ''Gunnera'' is the only known genus of angiosperms that hosts cyanobacteria, and the only known land plant with intracellular [[cyanobiont]]s. Although the endosymbionts enters the [[cell wall]], they do not penetrate the [[cell membrane]].<ref>{{cite book | url=https://books.google.com/books?id=_RxoEAAAQBAJ&dq=Nostoc+symbiotic+tissue+small+portion+total+Gunnera+biomass&pg=PA52 | title=Microbial Symbionts: Functions and Molecular Interactions on Host | isbn=9780323993357 | last1=Dharumadurai | first1=Dhanasekaran | date=25 September 2022 | publisher=Elsevier }}</ref><ref>{{cite journal | pmc=1203372 | year=2005 | last1=Chiu | first1=W. L. | last2=Peters | first2=G. A. | last3=Levieille | first3=G. | last4=Still | first4=P. C. | last5=Cousins | first5=S. | last6=Osborne | first6=B. | last7=Elhai | first7=J. | title=Nitrogen Deprivation Stimulates Symbiotic Gland Development in ''Gunnera manicata'' | journal=Plant Physiology | volume=139 | issue=1 | pages=224–230 | doi=10.1104/pp.105.064931 | pmid=16113217 }}</ref> This relationship may provide insights to allow the creation of novel symbioses between crop plants and cyanobacteria, allowing growth in areas lacking fixed nitrogen in the soil.