Gunnera Cyanobacteria symbiosis: Difference between revisions

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==<i>Gunnera</i>==
==<i>Gunnera</i>==
[[Image:Gunneratree.png|thumb|300px|right|The phylogenic tree of the Family <i>Gunneraceae</i>, consisting of only one genus <i>Gunnera</i>.[https://plantphylogeny.landcareresearch.co.nz/webforms/viewtree.aspx?ObjectID=e6155e0d-5659-4813-86f7-70a5f1c250ca].]]
[[Image:Gunneratree.png|thumb|300px|right|The phylogenic tree of the Family <i>Gunneraceae</i>, consisting of only one genus <i>Gunnera</i> <ref name=”NewZeland”>[https://plantphylogeny.landcareresearch.co.nz/webforms/viewtree.aspx?ObjectID=e6155e0d-5659-4813-86f7-70a5f1c250ca <i>Gunneraceae: gunnera.</i> Phylogeny of New Zealand Plants. (n.d.). Retrieved November 24, 2021, from https://plantphylogeny.landcareresearch.co.nz/webforms/viewtree.aspx?ObjectID=e6155e0d-5659-4813-86f7-70a5f1c250ca.]</ref>.]]
<i>Gunnera</i> is the only genus in the family <i>Gunneraceae</i> <ref name=”NewZeland”>[https://plantphylogeny.landcareresearch.co.nz/webforms/viewtree.aspx?ObjectID=e6155e0d-5659-4813-86f7-70a5f1c250ca <i>Gunneraceae: gunnera.</i> Phylogeny of New Zealand Plants. (n.d.). Retrieved November 24, 2021, from https://plantphylogeny.landcareresearch.co.nz/webforms/viewtree.aspx?ObjectID=e6155e0d-5659-4813-86f7-70a5f1c250ca.]</ref>. <i>Gunnera</i>, consisting of about 30-40 species, is a herbaceous flowering plant found primarily in the southern hemisphere <ref>[https://link.springer.com/article/10.1007/s006060170075 Wanntorp, L., Wanntorp, H. E., Oxelman, B., & Källersjö, M. (2001). Phylogeny of Gunnera. <i>Plant systematics and evolution, 226</i>(1), 85-107.]</ref> in places like Central and South America, Africa, Madagascar, Tasmania, New Zealand and Hawaii <ref name=”NewZeland”>[https://plantphylogeny.landcareresearch.co.nz/webforms/viewtree.aspx?ObjectID=e6155e0d-5659-4813-86f7-70a5f1c250ca <i>Gunneraceae: gunnera.</i> Phylogeny of New Zealand Plants. (n.d.). Retrieved November 24, 2021, from https://plantphylogeny.landcareresearch.co.nz/webforms/viewtree.aspx?ObjectID=e6155e0d-5659-4813-86f7-70a5f1c250ca.]</ref>.
<i>Gunnera</i> is the only genus in the family <i>Gunneraceae</i> <ref name=”NewZeland”>[https://plantphylogeny.landcareresearch.co.nz/webforms/viewtree.aspx?ObjectID=e6155e0d-5659-4813-86f7-70a5f1c250ca <i>Gunneraceae: gunnera.</i> Phylogeny of New Zealand Plants. (n.d.). Retrieved November 24, 2021, from https://plantphylogeny.landcareresearch.co.nz/webforms/viewtree.aspx?ObjectID=e6155e0d-5659-4813-86f7-70a5f1c250ca.]</ref>. <i>Gunnera</i>, consisting of about 30-40 species, is a herbaceous flowering plant found primarily in the southern hemisphere <ref>[https://link.springer.com/article/10.1007/s006060170075 Wanntorp, L., Wanntorp, H. E., Oxelman, B., & Källersjö, M. (2001). Phylogeny of Gunnera. <i>Plant systematics and evolution, 226</i>(1), 85-107.]</ref> in places like Central and South America, Africa, Madagascar, Tasmania, New Zealand and Hawaii <ref name=”NewZeland”>[https://plantphylogeny.landcareresearch.co.nz/webforms/viewtree.aspx?ObjectID=e6155e0d-5659-4813-86f7-70a5f1c250ca <i>Gunneraceae: gunnera.</i> Phylogeny of New Zealand Plants. (n.d.). Retrieved November 24, 2021, from https://plantphylogeny.landcareresearch.co.nz/webforms/viewtree.aspx?ObjectID=e6155e0d-5659-4813-86f7-70a5f1c250ca.]</ref>.


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<i>Gunnera manicata</i> is one of the largest species of <i>Gunnera</i> native to the Serra do Mar mountains of southeastern Brazil. Leaves range from 1.5 to 2.0 meters long <ref name=”everything”>[http://everything.explained.today/Gunnera/ <i>Gunnera Explained.</i> (n.d.). Retrieved November 24, 2021, from http://everything.explained.today/Gunnera/.] </ref> with an average diameter of 2.5m. Some leaves have been measured to be up to 3.3m across when cultivated <ref name="BBC1">[https://www.bbc.com/news/uk-england-berkshire-15308919 BBC. (2011, October 14). <i>Abbotsbury Gardens celebrates plant's 'monster' leaves</i>. BBC News. Retrieved November 24, 2021, from https://www.bbc.com/news/uk-england-berkshire-15308919] </ref>. In contrast, <i>Gunnera magellanica</i> is a species of <i>Gunnera</i> native to Chile, Argentina, the Falkland Islands, Peru, and Ecuador. The leaves of <i> G. magellanica</i> only grow 3-4 cm in diameter and leaf stalks reach 5-6 cm tall <ref>[https://link.springer.com/article/10.1007/BF02411385 Söderbäck, E., Lindblad, P., & Bergman, B. (1990). Developmental patterns related to nitrogen fixation in the Nostoc-Gunnera magellanica Lam. symbiosis. <i>Planta, 182</i>(3), 355-362.]</ref>.
<i>Gunnera manicata</i> is one of the largest species of <i>Gunnera</i> native to the Serra do Mar mountains of southeastern Brazil. Leaves range from 1.5 to 2.0 meters long <ref name=”everything”>[http://everything.explained.today/Gunnera/ <i>Gunnera Explained.</i> (n.d.). Retrieved November 24, 2021, from http://everything.explained.today/Gunnera/.] </ref> with an average diameter of 2.5m. Some leaves have been measured to be up to 3.3m across when cultivated <ref name="BBC1">[https://www.bbc.com/news/uk-england-berkshire-15308919 BBC. (2011, October 14). <i>Abbotsbury Gardens celebrates plant's 'monster' leaves</i>. BBC News. Retrieved November 24, 2021, from https://www.bbc.com/news/uk-england-berkshire-15308919] </ref>. In contrast, <i>Gunnera magellanica</i> is a species of <i>Gunnera</i> native to Chile, Argentina, the Falkland Islands, Peru, and Ecuador. The leaves of <i> G. magellanica</i> only grow 3-4 cm in diameter and leaf stalks reach 5-6 cm tall <ref>[https://link.springer.com/article/10.1007/BF02411385 Söderbäck, E., Lindblad, P., & Bergman, B. (1990). Developmental patterns related to nitrogen fixation in the Nostoc-Gunnera magellanica Lam. symbiosis. <i>Planta, 182</i>(3), 355-362.]</ref>.


[[Image:Gunnera.png|thumb|650px|center|<i>Gunnera manicata</i> leaves measure 1.5 to 2.0 meters [<ref name="BBC1">[https://www.bbc.com/news/uk-england-berkshire-15308919 BBC. (2011, October 14). <i>Abbotsbury Gardens celebrates plant's 'monster' leaves</i>. BBC News. Retrieved November 24, 2021, from https://www.bbc.com/news/uk-england-berkshire-15308919] </ref>] while <i>Gunnera magellanica</i> leaves measure only 3 to 4 cm [https://upload.wikimedia.org/wikipedia/commons/0/07/Devils_Strawberry_%283278834731%29.jpg].]]
[[Image:Gunnera.png|thumb|650px|center|<i>Gunnera manicata</i> leaves measure 1.5 to 2.0 meters <ref name="BBC1">[https://www.bbc.com/news/uk-england-berkshire-15308919 BBC. (2011, October 14). <i>Abbotsbury Gardens celebrates plant's 'monster' leaves</i>. BBC News. Retrieved November 24, 2021, from https://www.bbc.com/news/uk-england-berkshire-15308919] </ref> while <i>Gunnera magellanica</i> leaves measure only 3 to 4 cm <ref> https://upload.wikimedia.org/wikipedia/commons/0/07/Devils_Strawberry_%283278834731%29.jpg</ref>.]]


==Cyanobacteria==
==Cyanobacteria==
[[Image:Nostoc20.jpeg|thumb|200px|left|<i>Nostoc</i>, a genus of Cyanobacteria, create filaments of spherical or barrel-shaped cells that are green in color. [https://fmp.conncoll.edu/Silicasecchidisk/LucidKeys3.5/Keys_v3.5/Carolina35_Key/Media/Html/Nostoc_Main.html].]]  
[[Image:Nostoc20.jpeg|thumb|200px|left|<i>Nostoc</i>, a genus of Cyanobacteria, create filaments of spherical or barrel-shaped cells that are green in color <ref> [https://fmp.conncoll.edu/Silicasecchidisk/LucidKeys3.5/Keys_v3.5/Carolina35_Key/Media/Html/Nostoc_Main.html Nostoc Vaucher ex Bornet et Flahault. Cyanobacteria. (n.d.). Retrieved December 8, 2021.]</ref>.]]  




Cyanobacteria are the largest phylum of gram positive prokaryotes on earth dating back to 3.5 billion years ago<ref>[https://www.science.org/doi/abs/10.1126/science.11539686 Schopf, J. W., & Packer, B. M. (1987). Early Archean (3.3-billion to 3.5-billion-year-old) microfossils from Warrawoona Group, Australia. <i>Science, 237</i>(4810), 70-73.]</ref>. They evolved the ability to use photosynthesis to obtain their energy, making them different from other single celled organisms at the time <ref>[https://www.sciencedirect.com/science/article/pii/S0168945207003202?via%3Dihub Sinha, R. P., & Häder, D. P. (2008). UV-protectants in cyanobacteria. <i>Plant Science</i>, 174(3), 278-289.]</ref>. By photosynthesizing, the Cyanobacteria produce oxygen as a byproduct. This is believed to have both helped the bacteria successfully prosper because the environment in which they were developing was otherwise occupied by anaerobic bacteria and caused the Great Oxidation Event <ref>[https://books.google.com/books?hl=en&lr=&id=4oJ_vi27s18C&oi=fnd&pg=PR3&dq=Whitton+BA,+ed.+(2012).+%22The+fossil+record+of+cyanobacteria%22.+Ecology+of+Cyanobacteria+II:+Their+Diversity+in+Space+and+Time.+Springer+Science+%26+Business+Media.+pp.+17%E2%80%93.+&ots=JG1mYJsMTT&sig=yuPO7pmok3mkSV5sDkrOn0uGc4U#v=onepage&q=Whitton%20BA%2C%20ed.%20(2012).%20%22The%20fossil%20record%20of%20cyanobacteria%22.%20Ecology%20of%20Cyanobacteria%20II%3A%20Their%20Diversity%20in%20Space%20and%20Time.%20Springer%20Science%20%26%20Business%20Media.%20pp.%2017%E2%80%93.&f=false Whitton, B. A. (Ed.). (2012). <i>Ecology of cyanobacteria II: their diversity in space and time</i>. Springer Science & Business Media.]</ref>. The Great Oxidation Event is where the earth first experiences a rise in the amount of oxygen in the atmosphere and oceans<ref>[https://www.nature.com/articles/nature13068 Lyons, T. W., Reinhard, C. T., & Planavsky, N. J. (2014). The rise of oxygen in Earth’s early ocean and atmosphere. <i>Nature, 506</i>(7488), 307-315.]</ref>.  
Cyanobacteria are the largest phylum of gram positive prokaryotes on earth dating back to 3.5 billion years ago <ref>[https://www.jstor.org/stable/1699606?seq=1#metadata_info_tab_contents Schopf, J. W., & Packer, B. M. (1987). Early Archean (3.3-billion to 3.5-billion-year-old) microfossils from Warrawoona Group, Australia. <i>Science, 237</i>(4810), 70-73.]</ref>. They evolved the ability to use photosynthesis to obtain their energy, making them different from other single celled organisms at the time <ref>[https://www.sciencedirect.com/science/article/pii/S0168945207003202?via%3Dihub Sinha, R. P., & Häder, D. P. (2008). UV-protectants in cyanobacteria. <i>Plant Science</i>, 174(3), 278-289.]</ref>. By photosynthesizing, the Cyanobacteria produce oxygen as a byproduct. This is believed to have both helped the bacteria successfully prosper because the environment in which they were developing was otherwise occupied by anaerobic bacteria and caused the Great Oxidation Event <ref>[https://books.google.com/books?hl=en&lr=&id=4oJ_vi27s18C&oi=fnd&pg=PR3&dq=Whitton+BA,+ed.+(2012).+%22The+fossil+record+of+cyanobacteria%22.+Ecology+of+Cyanobacteria+II:+Their+Diversity+in+Space+and+Time.+Springer+Science+%26+Business+Media.+pp.+17%E2%80%93.+&ots=JG1mYJsMTT&sig=yuPO7pmok3mkSV5sDkrOn0uGc4U#v=onepage&q=Whitton%20BA%2C%20ed.%20(2012).%20%22The%20fossil%20record%20of%20cyanobacteria%22.%20Ecology%20of%20Cyanobacteria%20II%3A%20Their%20Diversity%20in%20Space%20and%20Time.%20Springer%20Science%20%26%20Business%20Media.%20pp.%2017%E2%80%93.&f=false Whitton, B. A. (Ed.). (2012). <i>Ecology of cyanobacteria II: their diversity in space and time</i>. Springer Science & Business Media.]</ref>. The Great Oxidation Event is where the earth first experiences a rise in the amount of oxygen in the atmosphere and oceans <ref>[https://www.nature.com/articles/nature13068 Lyons, T. W., Reinhard, C. T., & Planavsky, N. J. (2014). The rise of oxygen in Earth’s early ocean and atmosphere. <i>Nature, 506</i>(7488), 307-315.]</ref>.  
   
   
Many species of Cyanobacteria live in large colonies of cells ranging from hundreds to thousands of cells in a single colony <ref>[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3138769/ Tamulonis, C., Postma, M., & Kaandorp, J. (2011). Modeling filamentous cyanobacteria reveals the advantages of long and fast trichomes for optimizing light exposure. <i>PLoS One</i>, 6(7), e22084.]</ref>. These colonies are able to form filaments, sheets, or hollow spheres <ref name= "Aguilera" > [https://internal-journal.frontiersin.org/articles/10.3389/fmicb.2021.631654/full Aguilera, A., Klemenčič, M., Sueldo, D. J., Rzymski, P., Giannuzzi, L., & Martin, M. V. (2021). Cell death in Cyanobacteria: current understanding and recommendations for a consensus on its nomenclature. <i>Frontiers in Microbiology, 12</i>, 416.] </ref>. When too large, they can form algal blooms that can cause great harm to the aquatic ecosystem and the surrounding area in which it lives <ref>[https://link.springer.com/article/10.1007%2Fs00248-012-0159-y Paerl, H. W., & Otten, T. G. (2013). Harmful cyanobacterial blooms: causes, consequences, and controls. <i>Microbial ecology</i>, 65(4), 995-1010.(Pearl and Otten)]</ref>. Cyanobacteria can be found in almost any terrestrial or aquatic environment ranging from oceans and lakes to extremes like wet rocks in a desert or in the Antarctic <ref>[https://academic.oup.com/femsec/article/59/2/386/551614 De Los Ríos, A., Grube, M., Sancho, L. G., & Ascaso, C. (2007). Ultrastructural and genetic characteristics of endolithic cyanobacterial biofilms colonizing Antarctic granite rocks. <i>FEMS microbiology ecology, 59</i>(2), 386-395.]</ref>.
Many species of Cyanobacteria live in large colonies of cells ranging from hundreds to thousands of cells in a single colony <ref>[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3138769/ Tamulonis, C., Postma, M., & Kaandorp, J. (2011). Modeling filamentous cyanobacteria reveals the advantages of long and fast trichomes for optimizing light exposure. <i>PLoS One</i>, 6(7), e22084.]</ref>. These colonies are able to form filaments, sheets, or hollow spheres <ref name= "Aguilera" > [https://internal-journal.frontiersin.org/articles/10.3389/fmicb.2021.631654/full Aguilera, A., Klemenčič, M., Sueldo, D. J., Rzymski, P., Giannuzzi, L., & Martin, M. V. (2021). Cell death in Cyanobacteria: current understanding and recommendations for a consensus on its nomenclature. <i>Frontiers in Microbiology, 12</i>, 416.] </ref>. When too large, they can form algal blooms that can cause great harm to the aquatic ecosystem and the surrounding area in which it lives <ref>[https://link.springer.com/article/10.1007%2Fs00248-012-0159-y Paerl, H. W., & Otten, T. G. (2013). Harmful cyanobacterial blooms: causes, consequences, and controls. <i>Microbial ecology</i>, 65(4), 995-1010.(Pearl and Otten)]</ref>. Cyanobacteria can be found in almost any terrestrial or aquatic environment ranging from oceans and lakes to extremes like wet rocks in a desert or in the Antarctic <ref>[https://academic.oup.com/femsec/article/59/2/386/551614 De Los Ríos, A., Grube, M., Sancho, L. G., & Ascaso, C. (2007). Ultrastructural and genetic characteristics of endolithic cyanobacterial biofilms colonizing Antarctic granite rocks. <i>FEMS microbiology ecology, 59</i>(2), 386-395.]</ref>.
   
   
Cyanobacteria have been shown to make an important contribution to many biological cycles around the globe. Planktonic Cyanobacteria, specifically, are key sources of food in the aquatic food web. Cyanobacteria also are essential in contributing to major global biogeochemical cycles <ref name= "Aguilera" > [https://internal-journal.frontiersin.org/articles/10.3389/fmicb.2021.631654/full Aguilera, A., Klemenčič, M., Sueldo, D. J., Rzymski, P., Giannuzzi, L., & Martin, M. V. (2021). Cell death in Cyanobacteria: current understanding and recommendations for a consensus on its nomenclature. <i>Frontiers in Microbiology, 12</i>, 416.] </ref>. They have been shown to be responsible for a large portion of the earth’s N<sub>2</sub> and CO<sub>2</sub> fixation and fluctuations. N<sub>2</sub> fixation is a process where the Cyanobacteria can convert the nitrogen gas into ammonia, nitrites, and nitrates which can then be used by plants to make proteins and nucleic acids<ref>[https://academic.oup.com/jxb/article/59/5/1047/540713 Adams, D. G., & Duggan, P. S. (2008). Cyanobacteria–bryophyte symbioses. <i>Journal of Experimental Botany, 59</i>(5), 1047-1058.]</ref>. In CO<sub>2</sub> fixation, Cyanobacteria have large protein-shell bacterial microcompartments called carboxysomes which have been seen to take up inorganic carbon  and efficiently “fix” it into organic compounds that can then be used by living organisms<ref>[https://www.science.org/doi/10.1126/sciadv.aba1269 Hill, N. C., Tay, J. W., Altus, S., Bortz, D. M., & Cameron, J. C. (2020). Life cycle of a cyanobacterial carboxysome. <i>Science advances, 6</i>(19), eaba1269.]</ref>.
Cyanobacteria have been shown to make an important contribution to many biological cycles around the globe. Planktonic Cyanobacteria, specifically, are key sources of food in the aquatic food web. Cyanobacteria also are essential in contributing to major global biogeochemical cycles <ref name= "Aguilera" > [https://internal-journal.frontiersin.org/articles/10.3389/fmicb.2021.631654/full Aguilera, A., Klemenčič, M., Sueldo, D. J., Rzymski, P., Giannuzzi, L., & Martin, M. V. (2021). Cell death in Cyanobacteria: current understanding and recommendations for a consensus on its nomenclature. <i>Frontiers in Microbiology, 12</i>, 416.] </ref>. They have been shown to be responsible for a large portion of the earth’s N<sub>2</sub> and CO<sub>2</sub> fixation and fluctuations. N<sub>2</sub> fixation is a process where the Cyanobacteria can convert the nitrogen gas into ammonia, nitrites, and nitrates which can then be used by plants to make proteins and nucleic acids <ref>[https://academic.oup.com/jxb/article/59/5/1047/540713 Adams, D. G., & Duggan, P. S. (2008). Cyanobacteria–bryophyte symbioses. <i>Journal of Experimental Botany, 59</i>(5), 1047-1058.]</ref>. In CO<sub>2</sub> fixation, Cyanobacteria have large protein-shell bacterial microcompartments called carboxysomes which have been seen to take up inorganic carbon  and efficiently “fix” it into organic compounds that can then be used by living organisms <ref>[https://www.science.org/doi/10.1126/sciadv.aba1269 Hill, N. C., Tay, J. W., Altus, S., Bortz, D. M., & Cameron, J. C. (2020). Life cycle of a cyanobacterial carboxysome. <i>Science advances, 6</i>(19), eaba1269.]</ref>.


==<i>Gunnera</i> and <i>Cyanobacteria</i> symbiosis==
==<i>Gunnera</i> and <i>Cyanobacteria</i> symbiosis==
[[Image:gunneraredgland.jpeg|thumb|300px|left|<i>Gunnera</i> form red glands that secrete mucilage to attract <i>Nostoc</i>.[https://link.springer.com/referenceworkentry/10.1007%2F978-3-642-30194-0_17#Sec001717].]]  
[[Image:gunneraredgland.jpeg|thumb|300px|left|<i>Gunnera</i> form red glands that secrete mucilage to attract <i>Nostoc</i> <ref>[https://link.springer.com/referenceworkentry/10.1007%2F978-3-642-30194-0_17#citeas Adams D.G., Bergman B., Nierzwicki-Bauer S.A., Duggan P.S., Rai A.N., Schüßler A. (2013) Cyanobacterial-Plant Symbioses. In: Rosenberg E., DeLong E.F., Lory S., Stackebrandt E., Thompson F. (eds) The Prokaryotes. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-30194-0_17.]</ref>.]]  


===Unique Relationship===
===Unique Relationship===


The filamentous Cyanobacteria genus <i>Nostoc</i> has been observed to form colonies in both terrestrial and aquatic habitats. <i>Nostoc</i> has also been seen to screen damaging ultraviolet light and possesses the ability to fix atmospheric N<sub>2</sub> <ref>[https://onlinelibrary.wiley.com/doi/10.1111/j.0022-3646.1995.00002.x Dodds, W. K., Gudder, D. A., & Mollenhauer, D. (1995). The ecology of Nostoc. Journal of <i>Phycology, 31</i>(1), 2-18.]</ref>. For this reason, scientists believe several <i>Gunnera</i> species have developed a complex symbiotic relationship with <i>Nostoc</i>. This relationship is the only known relationship between a cyanobacterium and an angiosperm <ref name="abc">[https://nph.onlinelibrary.wiley.com/doi/10.1111/j.1469-8137.1992.tb00067.x Bergman, B., Johansson, C., & Söderbäck, E. (1992). The Nostoc–Gunnera symbiosis. <i>New Phytologist, 122</i>(3), 379-400.]</ref>. Even more compelling is that <i>Nostoc</i> is the only genus of Cyanobacteria that have been observed to be in a symbiotic relationship with <i>Gunnera</i> based on 16S rRNA analyses <ref>[https://link.springer.com/article/10.1007/s002030100313 Rasmussen, U., & Svenning, M. M. (2001). Characterization by genotypic methods of symbiotic Nostoc strains isolated from five species of Gunnera. <i>Archives of microbiology, 176</i>(3), 204-210.]</ref>.
The filamentous Cyanobacteria genus <i>Nostoc</i> has been observed to form colonies in both terrestrial and aquatic habitats. <i>Nostoc</i> has also been seen to screen damaging ultraviolet light and possesses the ability to fix atmospheric N<sub>2</sub> <ref>[https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.0022-3646.1995.00002.x Dodds, W. K., Gudder, D. A., & Mollenhauer, D. (1995). The ecology of Nostoc. Journal of <i>Phycology, 31</i>(1), 2-18.]</ref>. For this reason, scientists believe several <i>Gunnera</i> species have developed a complex symbiotic relationship with <i>Nostoc</i>. This relationship is the only known relationship between a cyanobacterium and an angiosperm <ref name="abc">[https://nph.onlinelibrary.wiley.com/doi/epdf/10.1111/j.1469-8137.1992.tb00067.x Bergman, B., Johansson, C., & Söderbäck, E. (1992). The Nostoc–Gunnera symbiosis. <i>New Phytologist, 122</i>(3), 379-400.]</ref>. Even more compelling is that <i>Nostoc</i> is the only genus of Cyanobacteria that have been observed to be in a symbiotic relationship with <i>Gunnera</i> based on 16S rRNA analyses <ref>[https://link.springer.com/article/10.1007/s002030100313 Rasmussen, U., & Svenning, M. M. (2001). Characterization by genotypic methods of symbiotic Nostoc strains isolated from five species of Gunnera. <i>Archives of microbiology, 176</i>(3), 204-210.]</ref>.


===Stages of Symbiosis===
===Stages of Symbiosis===


[[Image:Nostochetero.jpeg|thumb|350px|right|<i>Nostoc</i> differentiate into heterocysts.[https://www.plantscience4u.com/2018/10/heterocyst-of-nostoc-structure-and-function.html].]]  
[[Image:Nostochetero.jpeg|thumb|350px|right|The arrow shows <i>Nostoc</i> cells that have differentiated into heterocysts for N<sub>2</sub> fixation <ref>[https://www.plantscience4u.com/2018/10/heterocyst-of-nostoc-structure-and-function.html Haneef, J. (2018, October 14). Heterocyst of Nostoc structure and function. Plant Science 4 U. Retrieved December 8, 2021, from https://www.plantscience4u.com/2018/10/heterocyst-of-nostoc-structure-and-function.html.]</ref>.]]  


The symbiosis takes place when the <i>Nostoc</i> bacteria enter into the <i>Gunnera</i> by way of specialized gland organs on the stems of the plants <ref name="abc">[https://nph.onlinelibrary.wiley.com/doi/10.1111/j.1469-8137.1992.tb00067.x Bergman, B., Johansson, C., & Söderbäck, E. (1992). The Nostoc–Gunnera symbiosis. <i>New Phytologist, 122</i>(3), 379-400.]</ref>. According to research conducted by Johansson and Bergman (1992), establishing the symbiotic relationship between <i>Nostoc</i> and <i>Gunnera</i> takes place in a series of 6 stages: 1) Gland development and mucilage secretion, 2) Collection of Cyanobacteria on the gland, 3) Hormogonia, motile filaments of Cyanobacteria, enter <i>Gunnera</i>, 4) <i>Nostoc</i> can be detected between the cell walls and folds of the <i>Gunnera</i>, 5) <i>Nostoc</i> enters the host cells, and 6) <i>Nostoc</i> cells differentiated into heterocysts <ref name=”#Bergman”>[https://link.springer.com/article/10.1007/BF00192808 Johansson, C., & Bergman, B. (1992). Early events during the establishment of the Gunnera/Nostoc symbiosis. <i>Planta, 188</i>(3), 403-413.]</ref>. A small red gland develops on the <i>Gunnera</i> right below the base of the leaf when the plant is experiencing nitrogen deprivation, possibly using the C/N-sensing mechanism as a way of regulation. The growth of the gland is further sped up if the plant is also experiencing surroundings with high levels of carbon from sucrose. The gland can be found as early as the cotyledon stage of the plant’s development <ref name=”ChiuW”>[https://academic.oup.com/plphys/article/139/1/224/6113376?login=true Chiu, W. L., Peters, G. A., Levieille, G., Still, P. C., Cousins, S., Osborne, B., & Elhai, J. (2005). Nitrogen deprivation stimulates symbiotic gland development in Gunnera manicata. <i>Plant Physiology, 139</i>(1), 224-230.]</ref>. The glands then secrete a solution that attracts the <i>Nostoc</i> <ref>[https://www.sciencedirect.com/science/article/pii/B9780444528575500126 Pawlowski, K., & Bergman, B. (2007). Plant symbioses with Frankia and cyanobacteria. In <i>Biology of the Nitrogen Cycle </i>(pp. 165-178). Elsevier.]</ref>. The solution is a mucilage that has low levels of soluble sugars that attracts the <i>Nostoc</i> to the <i>Gunnera</i> <ref>[https://academic.oup.com/plphys/article/154/3/1381/6111354?login=true Khamar, H. J., Breathwaite, E. K., Prasse, C. E., Fraley, E. R., Secor, C. R., Chibane, F. L., ... & Chiu, W. L. (2010). Multiple roles of soluble sugars in the establishment of Gunnera-Nostoc endosymbiosis. Plant physiology, 154(3), 1381-1389.]</ref>. Although other bacteria are attracted to the mucilage as well, only the <i>Nostoc</i> are able to enter the glands. Within three day of the first detection of the hormogonia on the mature gland, the colony of <i>Nostoc</i> is established. Because of the nature of <i>Nostoc</i> to follow previous paths of other hormogonia, more <i>Nostoc</i> are possibly also enticed to invade the plant as well <ref name=”ChiuW”>[https://academic.oup.com/plphys/article/139/1/224/6113376?login=true Chiu, W. L., Peters, G. A., Levieille, G., Still, P. C., Cousins, S., Osborne, B., & Elhai, J. (2005). Nitrogen deprivation stimulates symbiotic gland development in Gunnera manicata. <i>Plant Physiology, 139</i>(1), 224-230.]</ref>. The glands of the <i>Gunnera</i> consist of nine papillae surrounding one central papillae <ref name=”ChiuW”>[https://academic.oup.com/plphys/article/139/1/224/6113376?login=true Chiu, W. L., Peters, G. A., Levieille, G., Still, P. C., Cousins, S., Osborne, B., & Elhai, J. (2005). Nitrogen deprivation stimulates symbiotic gland development in Gunnera manicata. <i>Plant Physiology, 139</i>(1), 224-230.]</ref>. Between the papillae, the <i>Nostoc</i> are able to enter the cell by way of channels from which the mucilage is released. While moving down into the <i>Gunnera</i>, the <i>Nostoc</i> moves in between the cell walls of the plant cells.  The cell walls of the <i>Gunnera</i> are then dissolved where <i>Nostoc</i> is in close proximity. This allows the <i>Nostoc</i> to “invade” the cells. <ref name=”#Bergman”>[https://link.springer.com/article/10.1007/BF00192808 Johansson, C., & Bergman, B. (1992). Early events during the establishment of the Gunnera/Nostoc symbiosis. <i>Planta, 188</i>(3), 403-413.]</ref>. <i>Nostoc</i> then enters the cells of the  <i>Gunnera</i> where it produces N<sub>2</sub>-fixing cells <ref name="abc">[https://nph.onlinelibrary.wiley.com/doi/10.1111/j.1469-8137.1992.tb00067.x Bergman, B., Johansson, C., & Söderbäck, E. (1992). The Nostoc–Gunnera symbiosis. <i>New Phytologist, 122</i>(3), 379-400.]</ref>. These cells are known as heterocysts which are thick walled, specialized N-fixing cells <ref>[https://www.sciencedirect.com/science/article/pii/B9780128114056000037 Borowitzka, M. A. (2018). Biology of microalgae. In <i>Microalgae in health and disease prevention </i>(pp. 23-72). Academic Press.]</ref>. The nitrogen fixation allows the <i>Gunnera</i> to grow and thrive in its environment <ref name="Gautam">[https://www.sciencedirect.com/science/article/pii/B9780128212189000116 Gautam, K., Rajvanshi, M., Chugh, N., Dixit, R. B., Kumar, G. R. K., Kumar, C., ... & Dasgupta, S. (2021). Microalgal applications toward agricultural sustainability: Recent trends and future prospects. <i>Microalgae</i>, 339-379.]</ref>.
The symbiosis takes place when the <i>Nostoc</i> bacteria enter into the <i>Gunnera</i> by way of specialized gland organs on the stems of the plants <ref name="abc">[https://nph.onlinelibrary.wiley.com/doi/epdf/10.1111/j.1469-8137.1992.tb00067.x Bergman, B., Johansson, C., & Söderbäck, E. (1992). The Nostoc–Gunnera symbiosis. <i>New Phytologist, 122</i>(3), 379-400.]</ref>. According to research conducted by Johansson and Bergman (1992), establishing the symbiotic relationship between <i>Nostoc</i> and <i>Gunnera</i> takes place in a series of 6 stages: 1) Gland development and mucilage secretion, 2) Collection of Cyanobacteria on the gland, 3) Hormogonia, motile filaments of Cyanobacteria, enter <i>Gunnera</i>, 4) <i>Nostoc</i> can be detected between the cell walls and folds of the <i>Gunnera</i>, 5) <i>Nostoc</i> enters the host cells, and 6) <i>Nostoc</i> cells differentiated into heterocysts <ref name=”#Bergman”>[https://link.springer.com/article/10.1007/BF00192808 Johansson, C., & Bergman, B. (1992). Early events during the establishment of the Gunnera/Nostoc symbiosis. <i>Planta, 188</i>(3), 403-413.]</ref>. A small red gland develops on the <i>Gunnera</i> right below the base of the leaf when the plant is experiencing nitrogen deprivation, possibly using the C/N-sensing mechanism as a way of regulation. The growth of the gland is further sped up if the plant is also experiencing surroundings with high levels of carbon from sucrose. The gland can be found as early as the cotyledon stage of the plant’s development <ref name=”ChiuW”>[https://academic.oup.com/plphys/article/139/1/224/6113376?login=true Chiu, W. L., Peters, G. A., Levieille, G., Still, P. C., Cousins, S., Osborne, B., & Elhai, J. (2005). Nitrogen deprivation stimulates symbiotic gland development in Gunnera manicata. <i>Plant Physiology, 139</i>(1), 224-230.]</ref>. The glands then secrete a solution that attracts the <i>Nostoc</i> <ref>[https://books.google.com/books?hl=en&lr=&id=qmZDpnV-sYYC&oi=fnd&pg=PA165&ots=Pdi88sOowq&sig=y6mWYTpQx2Z8hVGBgCfb-CtGAQc#v=onepage&q&f=false Pawlowski, K., & Bergman, B. (2007). Plant symbioses with Frankia and cyanobacteria. In <i>Biology of the Nitrogen Cycle </i>(pp. 165-178). Elsevier.]</ref>. The solution is mucilage that has low levels of soluble sugars that attracts the <i>Nostoc</i> to the <i>Gunnera</i> <ref>[https://academic.oup.com/plphys/article/154/3/1381/6111354?login=true Khamar, H. J., Breathwaite, E. K., Prasse, C. E., Fraley, E. R., Secor, C. R., Chibane, F. L., ... & Chiu, W. L. (2010). Multiple roles of soluble sugars in the establishment of Gunnera-Nostoc endosymbiosis. Plant physiology, 154(3), 1381-1389.]</ref>. Although other bacteria are attracted to the mucilage as well, only the <i>Nostoc</i> are able to enter the glands. Within three days of the first detection of the hormogonia on the mature gland, the colony of <i>Nostoc</i> is established. Because of the nature of <i>Nostoc</i> to follow previous paths of other hormogonia, more <i>Nostoc</i> are possibly also enticed to invade the plant as well <ref name=”ChiuW”>[https://academic.oup.com/plphys/article/139/1/224/6113376?login=true Chiu, W. L., Peters, G. A., Levieille, G., Still, P. C., Cousins, S., Osborne, B., & Elhai, J. (2005). Nitrogen deprivation stimulates symbiotic gland development in Gunnera manicata. <i>Plant Physiology, 139</i>(1), 224-230.]</ref>. The glands of the <i>Gunnera</i> consist of nine papillae surrounding one central papillae <ref name=”ChiuW”>[https://academic.oup.com/plphys/article/139/1/224/6113376?login=true Chiu, W. L., Peters, G. A., Levieille, G., Still, P. C., Cousins, S., Osborne, B., & Elhai, J. (2005). Nitrogen deprivation stimulates symbiotic gland development in Gunnera manicata. <i>Plant Physiology, 139</i>(1), 224-230.]</ref>. Between the papillae, the <i>Nostoc</i> are able to enter the cell by way of channels from which the mucilage is released. While moving down into the <i>Gunnera</i>, the <i>Nostoc</i> moves in between the cell walls of the plant cells.  The cell walls of the <i>Gunnera</i> are then dissolved where <i>Nostoc</i> is in close proximity. This allows the <i>Nostoc</i> to “invade” the cells <ref name=”#Bergman”>[https://link.springer.com/article/10.1007/BF00192808 Johansson, C., & Bergman, B. (1992). Early events during the establishment of the Gunnera/Nostoc symbiosis. <i>Planta, 188</i>(3), 403-413.]</ref>. <i>Nostoc</i> then enters the cells of the  <i>Gunnera</i> where it produces N<sub>2</sub>-fixing cells <ref name="abc">[https://nph.onlinelibrary.wiley.com/doi/epdf/10.1111/j.1469-8137.1992.tb00067.x Bergman, B., Johansson, C., & Söderbäck, E. (1992). The Nostoc–Gunnera symbiosis. <i>New Phytologist, 122</i>(3), 379-400.]</ref>. These cells are known as heterocysts which are thick walled, specialized N-fixing cells <ref>[https://www.sciencedirect.com/science/article/pii/B9780128114056000037 Borowitzka, M. A. (2018). Biology of microalgae. In <i>Microalgae in health and disease prevention </i>(pp. 23-72). Academic Press.]</ref>. The nitrogen fixation allows the <i>Gunnera</i> to grow and thrive in its environment <ref name="Gautam">[https://www.sciencedirect.com/science/article/pii/B9780128212189000116 Gautam, K., Rajvanshi, M., Chugh, N., Dixit, R. B., Kumar, G. R. K., Kumar, C., ... & Dasgupta, S. (2021). Microalgal applications toward agricultural sustainability: Recent trends and future prospects. <i>Microalgae</i>, 339-379.]</ref>.


===Benefits===
===Benefits===


Previous studies have revealed that <i>Gunnera</i> is unable to use nitrate because it lacks the enzyme nitrate reductase. <i>Nostoc</i> is able to fix nitrogen to fill the needs of the <i>Gunnera</i> <ref>[https://www.sciencedirect.com/science/article/pii/B0123485304004574 Sprent, J.I. (2005). NITROGEN IN SOILS | Symbiotic Fixation. In <i>Encyclopedia of Soils in the Environment</i>(pp. 46-56). Elsevier.]</ref>.  In return, the <i>Nostoc</i> gets reduced carbon from the plant that it uses for nutrients since it is unable to photosynthesize due to lack of sunlight. The plant also provides the bacteria with a habitat where it can thrive <ref name="Gautam">[https://www.sciencedirect.com/science/article/pii/B9780128212189000116 Gautam, K., Rajvanshi, M., Chugh, N., Dixit, R. B., Kumar, G. R. K., Kumar, C., ... & Dasgupta, S. (2021). Microalgal applications toward agricultural sustainability: Recent trends and future prospects. <i>Microalgae</i>, 339-379.]</ref>. With the cells of the <i>Gunnera</i> now filled with the <i>Nostoc</i>, the plant must control the numbers of bacteria to avoid overgrowth through monitoring the exchange of nutrients to the bacteria <ref>[https://www.cambridge.org/core/journals/new-phytologist/article/abs/tansley-review-no-116-cyanobacteriumplant-symbioses/89EF6312AACFEDF168DB185361D0983D  Rai, A. N., Söderbäck, E., & Bergman, B. (2000). Cyanobacterium-plant symbioses. <i>New Phytologist, 147</i>(3), 449-481.]</ref>.
Previous studies have revealed that <i>Gunnera</i> is unable to use nitrate because it lacks the enzyme nitrate reductase. <i>Nostoc</i> is able to fix nitrogen to fill the needs of the <i>Gunnera</i> <ref>[https://www.sciencedirect.com/science/article/pii/B0123485304004574 Sprent, J.I. (2005). NITROGEN IN SOILS | Symbiotic Fixation. In <i>Encyclopedia of Soils in the Environment</i>(pp. 46-56). Elsevier.]</ref>.  In return, the <i>Nostoc</i> gets reduced carbon from the plant that it uses for nutrients since it is unable to photosynthesize due to lack of sunlight. The plant also provides the bacteria with a habitat where it can thrive <ref name="Gautam">[https://www.sciencedirect.com/science/article/pii/B9780128212189000116 Gautam, K., Rajvanshi, M., Chugh, N., Dixit, R. B., Kumar, G. R. K., Kumar, C., ... & Dasgupta, S. (2021). Microalgal applications toward agricultural sustainability: Recent trends and future prospects. <i>Microalgae</i>, 339-379.]</ref>. With the cells of the <i>Gunnera</i> now filled with the <i>Nostoc</i>, the plant must control the numbers of bacteria to avoid overgrowth through monitoring the exchange of nutrients to the bacteria <ref>[https://nph-onlinelibrary-wiley-com.libproxy.kenyon.edu/doi/epdf/10.1046/j.1469-8137.2000.00720.x Rai, A. N., Söderbäck, E., & Bergman, B. (2000). Cyanobacterium-plant symbioses. <i>New Phytologist, 147</i>(3), 449-481.]</ref>.


===Genetic Changes in <i>Nostoc</i>===
===Genetic Changes in <i>Nostoc</i>===
Line 42: Line 42:
==Conclusion==
==Conclusion==


<i>Gunnera</i> is an angiosperm which grows in the southern hemisphere. The plant has developed a symbiotic relationship with <i>Nostoc</i>, a genus of Cyanobacteria that can fix nitrogen because the <i>Gunnera</i> is unable to produce its own nitrogen. A Cyanobacterium is a photosynthesizing bacterium that is thought to have caused the Great Oxidation Event where the earth's atmosphere and oceans had it first rise in oxygen levels making the life present today possible. Through the symbiotic relationship, the <i>Gunnera</i> species are able to obtain the nitrogen they need to survive and the <i>Nostoc</i> are able to have a protected area to live and obtain carbon from the <i>Gunnera</i> since it is no longer able to photosynthesize.
A Cyanobacterium is a photosynthesizing bacterium that is thought to have caused the Great Oxidation Event where the earth's atmosphere and oceans had it first rise in oxygen levels making the life present today possible. <i>Gunnera</i> is a genus of angiosperm which grows in the southern hemisphere that lacks the ability to produce its own nitrogen it need to survive. To compensate for that lack in ability, <i>Gunnera</i> has evolved a symbiotic relationship with <i>Nostoc</i>, a genus of Cyanobacteria that has nitrogen fixation ability, to obtain nitrogen. Though the symbiosis, the <i>Nostoc</i> acquire a protected area to live and obtain carbon from the <i>Gunnera</i> since it is no longer able to photosynthesize while living in the plant.


==References==
==References==

Latest revision as of 02:28, 9 December 2021

Gunnera

The phylogenic tree of the Family Gunneraceae, consisting of only one genus Gunnera [1].

Gunnera is the only genus in the family Gunneraceae [1]. Gunnera, consisting of about 30-40 species, is a herbaceous flowering plant found primarily in the southern hemisphere [2] in places like Central and South America, Africa, Madagascar, Tasmania, New Zealand and Hawaii [1].

Some species of Gunnera have well documented uses. Gunnera tinctoria, for example, is often used in dishes and liquors in Southern Chile and Argentina [3]. It is also known to be used as a medical herb for respiratory diseases, gastrointestinal problems, and as an anti-inflammatory [4].

Gunnera manicata is one of the largest species of Gunnera native to the Serra do Mar mountains of southeastern Brazil. Leaves range from 1.5 to 2.0 meters long [3] with an average diameter of 2.5m. Some leaves have been measured to be up to 3.3m across when cultivated [5]. In contrast, Gunnera magellanica is a species of Gunnera native to Chile, Argentina, the Falkland Islands, Peru, and Ecuador. The leaves of G. magellanica only grow 3-4 cm in diameter and leaf stalks reach 5-6 cm tall [6].

Gunnera manicata leaves measure 1.5 to 2.0 meters [5] while Gunnera magellanica leaves measure only 3 to 4 cm [7].

Cyanobacteria

Nostoc, a genus of Cyanobacteria, create filaments of spherical or barrel-shaped cells that are green in color [8].


Cyanobacteria are the largest phylum of gram positive prokaryotes on earth dating back to 3.5 billion years ago [9]. They evolved the ability to use photosynthesis to obtain their energy, making them different from other single celled organisms at the time [10]. By photosynthesizing, the Cyanobacteria produce oxygen as a byproduct. This is believed to have both helped the bacteria successfully prosper because the environment in which they were developing was otherwise occupied by anaerobic bacteria and caused the Great Oxidation Event [11]. The Great Oxidation Event is where the earth first experiences a rise in the amount of oxygen in the atmosphere and oceans [12].

Many species of Cyanobacteria live in large colonies of cells ranging from hundreds to thousands of cells in a single colony [13]. These colonies are able to form filaments, sheets, or hollow spheres [14]. When too large, they can form algal blooms that can cause great harm to the aquatic ecosystem and the surrounding area in which it lives [15]. Cyanobacteria can be found in almost any terrestrial or aquatic environment ranging from oceans and lakes to extremes like wet rocks in a desert or in the Antarctic [16].

Cyanobacteria have been shown to make an important contribution to many biological cycles around the globe. Planktonic Cyanobacteria, specifically, are key sources of food in the aquatic food web. Cyanobacteria also are essential in contributing to major global biogeochemical cycles [14]. They have been shown to be responsible for a large portion of the earth’s N2 and CO2 fixation and fluctuations. N2 fixation is a process where the Cyanobacteria can convert the nitrogen gas into ammonia, nitrites, and nitrates which can then be used by plants to make proteins and nucleic acids [17]. In CO2 fixation, Cyanobacteria have large protein-shell bacterial microcompartments called carboxysomes which have been seen to take up inorganic carbon and efficiently “fix” it into organic compounds that can then be used by living organisms [18].

Gunnera and Cyanobacteria symbiosis

Gunnera form red glands that secrete mucilage to attract Nostoc [19].

Unique Relationship

The filamentous Cyanobacteria genus Nostoc has been observed to form colonies in both terrestrial and aquatic habitats. Nostoc has also been seen to screen damaging ultraviolet light and possesses the ability to fix atmospheric N2 [20]. For this reason, scientists believe several Gunnera species have developed a complex symbiotic relationship with Nostoc. This relationship is the only known relationship between a cyanobacterium and an angiosperm [21]. Even more compelling is that Nostoc is the only genus of Cyanobacteria that have been observed to be in a symbiotic relationship with Gunnera based on 16S rRNA analyses [22].

Stages of Symbiosis

The arrow shows Nostoc cells that have differentiated into heterocysts for N2 fixation [23].

The symbiosis takes place when the Nostoc bacteria enter into the Gunnera by way of specialized gland organs on the stems of the plants [21]. According to research conducted by Johansson and Bergman (1992), establishing the symbiotic relationship between Nostoc and Gunnera takes place in a series of 6 stages: 1) Gland development and mucilage secretion, 2) Collection of Cyanobacteria on the gland, 3) Hormogonia, motile filaments of Cyanobacteria, enter Gunnera, 4) Nostoc can be detected between the cell walls and folds of the Gunnera, 5) Nostoc enters the host cells, and 6) Nostoc cells differentiated into heterocysts [24]. A small red gland develops on the Gunnera right below the base of the leaf when the plant is experiencing nitrogen deprivation, possibly using the C/N-sensing mechanism as a way of regulation. The growth of the gland is further sped up if the plant is also experiencing surroundings with high levels of carbon from sucrose. The gland can be found as early as the cotyledon stage of the plant’s development [25]. The glands then secrete a solution that attracts the Nostoc [26]. The solution is mucilage that has low levels of soluble sugars that attracts the Nostoc to the Gunnera [27]. Although other bacteria are attracted to the mucilage as well, only the Nostoc are able to enter the glands. Within three days of the first detection of the hormogonia on the mature gland, the colony of Nostoc is established. Because of the nature of Nostoc to follow previous paths of other hormogonia, more Nostoc are possibly also enticed to invade the plant as well [25]. The glands of the Gunnera consist of nine papillae surrounding one central papillae [25]. Between the papillae, the Nostoc are able to enter the cell by way of channels from which the mucilage is released. While moving down into the Gunnera, the Nostoc moves in between the cell walls of the plant cells. The cell walls of the Gunnera are then dissolved where Nostoc is in close proximity. This allows the Nostoc to “invade” the cells [24]. Nostoc then enters the cells of the Gunnera where it produces N2-fixing cells [21]. These cells are known as heterocysts which are thick walled, specialized N-fixing cells [28]. The nitrogen fixation allows the Gunnera to grow and thrive in its environment [29].

Benefits

Previous studies have revealed that Gunnera is unable to use nitrate because it lacks the enzyme nitrate reductase. Nostoc is able to fix nitrogen to fill the needs of the Gunnera [30]. In return, the Nostoc gets reduced carbon from the plant that it uses for nutrients since it is unable to photosynthesize due to lack of sunlight. The plant also provides the bacteria with a habitat where it can thrive [29]. With the cells of the Gunnera now filled with the Nostoc, the plant must control the numbers of bacteria to avoid overgrowth through monitoring the exchange of nutrients to the bacteria [31].

Genetic Changes in Nostoc

Once the Nostoc has successfully “invaded” the Gunnera, gene transcription changes happen within the Nostoc where genes associated with heterocyst differentiation and nitrogen fixation are amplified. The hetR gene frequency, which is a gene involved in regulating heterocyst differentiation, is increased. hetR is positively correlated with heterocyst frequency increases and ntcA expression which codes for nitrogen-responsive transcription factors. nifH, which codes for dinitrogen fixation, continues to be high as observed in bacteria that are not in an endosymbiotic relationship with Gunnera, however, glnB (PII) decreases when the bacteria is in the symbiotic relationship [32].

Conclusion

A Cyanobacterium is a photosynthesizing bacterium that is thought to have caused the Great Oxidation Event where the earth's atmosphere and oceans had it first rise in oxygen levels making the life present today possible. Gunnera is a genus of angiosperm which grows in the southern hemisphere that lacks the ability to produce its own nitrogen it need to survive. To compensate for that lack in ability, Gunnera has evolved a symbiotic relationship with Nostoc, a genus of Cyanobacteria that has nitrogen fixation ability, to obtain nitrogen. Though the symbiosis, the Nostoc acquire a protected area to live and obtain carbon from the Gunnera since it is no longer able to photosynthesize while living in the plant.

References

  1. 1.0 1.1 1.2 Gunneraceae: gunnera. Phylogeny of New Zealand Plants. (n.d.). Retrieved November 24, 2021, from https://plantphylogeny.landcareresearch.co.nz/webforms/viewtree.aspx?ObjectID=e6155e0d-5659-4813-86f7-70a5f1c250ca.
  2. Wanntorp, L., Wanntorp, H. E., Oxelman, B., & Källersjö, M. (2001). Phylogeny of Gunnera. Plant systematics and evolution, 226(1), 85-107.
  3. 3.0 3.1 Gunnera Explained. (n.d.). Retrieved November 24, 2021, from http://everything.explained.today/Gunnera/.
  4. Molares, S., & Ladio, A. (2014). Medicinal plants in the cultural landscape of a Mapuche-Tehuelche community in arid Argentine Patagonia: an eco-sensorial approach. Journal of ethnobiology and ethnomedicine, 10(1), 1-14.
  5. 5.0 5.1 BBC. (2011, October 14). Abbotsbury Gardens celebrates plant's 'monster' leaves. BBC News. Retrieved November 24, 2021, from https://www.bbc.com/news/uk-england-berkshire-15308919
  6. Söderbäck, E., Lindblad, P., & Bergman, B. (1990). Developmental patterns related to nitrogen fixation in the Nostoc-Gunnera magellanica Lam. symbiosis. Planta, 182(3), 355-362.
  7. https://upload.wikimedia.org/wikipedia/commons/0/07/Devils_Strawberry_%283278834731%29.jpg
  8. Nostoc Vaucher ex Bornet et Flahault. Cyanobacteria. (n.d.). Retrieved December 8, 2021.
  9. Schopf, J. W., & Packer, B. M. (1987). Early Archean (3.3-billion to 3.5-billion-year-old) microfossils from Warrawoona Group, Australia. Science, 237(4810), 70-73.
  10. Sinha, R. P., & Häder, D. P. (2008). UV-protectants in cyanobacteria. Plant Science, 174(3), 278-289.
  11. Whitton, B. A. (Ed.). (2012). Ecology of cyanobacteria II: their diversity in space and time. Springer Science & Business Media.
  12. Lyons, T. W., Reinhard, C. T., & Planavsky, N. J. (2014). The rise of oxygen in Earth’s early ocean and atmosphere. Nature, 506(7488), 307-315.
  13. Tamulonis, C., Postma, M., & Kaandorp, J. (2011). Modeling filamentous cyanobacteria reveals the advantages of long and fast trichomes for optimizing light exposure. PLoS One, 6(7), e22084.
  14. 14.0 14.1 Aguilera, A., Klemenčič, M., Sueldo, D. J., Rzymski, P., Giannuzzi, L., & Martin, M. V. (2021). Cell death in Cyanobacteria: current understanding and recommendations for a consensus on its nomenclature. Frontiers in Microbiology, 12, 416.
  15. Paerl, H. W., & Otten, T. G. (2013). Harmful cyanobacterial blooms: causes, consequences, and controls. Microbial ecology, 65(4), 995-1010.(Pearl and Otten)
  16. De Los Ríos, A., Grube, M., Sancho, L. G., & Ascaso, C. (2007). Ultrastructural and genetic characteristics of endolithic cyanobacterial biofilms colonizing Antarctic granite rocks. FEMS microbiology ecology, 59(2), 386-395.
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Edited by Rachael Tomasko, student of Joan Slonczewski for BIOL 116 Information in Living Systems, 2021, Kenyon College.