Array ( [0] => {{Short description|Fungus-plant symbiotic association}} [1] => {{multiple image |perrow=2 |total_width=350 [2] => |image1=Amanita_muscaria_fruit_bodies.jpg |width1=600 |height1=446 [3] => |image2=Mycorrhizal_root_tips_(amanita).jpg |width2=600 |height2=446 [4] => |image3=Arbuscular_mycorrhiza_microscope.jpg |width3=2048 |height3=1536 [5] => |image4=Wheat_P1210892.jpg |width4=2560 |height4=1920 [6] => |footer=Many conspicuous fungi such as the [[fly agaric]] (upper left) form [[ectomycorrhiza]] (upper right) with tree rootlets. [[Arbuscular mycorrhiza]] (lower left) are very common in plants, including crop species such as [[wheat]] (lower right)}} [7] => [8] => A '''mycorrhiza''' (from [[Ancient Greek|Greek]] μύκης ''{{lang |grc-Latn |mýkēs}}'', "fungus", and ῥίζα ''{{lang |grc-Latn |rhiza}}'', "root"; {{plural form}}: '''mycorrhizae''', '''mycorrhiza''' or '''mycorrhizas'''{{cite web |last1=Deacon |first1=Jim |title=The Microbial World: Mycorrhizas |url=http://archive.bio.ed.ac.uk/jdeacon/microbes/mycorrh.htm |url-status=dead |archive-url=https://web.archive.org/web/20180427082137/http://archive.bio.ed.ac.uk/jdeacon/microbes/mycorrh.htm |archive-date=2018-04-27 |access-date=11 January 2019 |website=bio.ed.ac.uk (archived)}}) is a [[symbiosis|symbiotic]] association between a [[fungus]] and a [[plant]].{{Cite book |last1=Kirk |first1=P. M. |first2=P. F. |last2=Cannon |first3=J. C. |last3=David |first4=J. |last4=Stalpers |date=2001 |title=Ainsworth and Bisby's Dictionary of the Fungi |edition=9th |publisher=CAB International |location=Wallingford, UK }} The term mycorrhiza refers to the role of the fungus in the plant's [[rhizosphere]], its [[root]] system. Mycorrhizae play important roles in [[plant nutrition]], [[soil life|soil biology]], and [[soil chemistry]]. [9] => [10] => In a mycorrhizal association, the fungus colonizes the host plant's root tissues, either [[intracellular]]ly as in [[arbuscular mycorrhizal fungi]], or [[extracellular]]ly as in [[#Ectomycorrhiza|ectomycorrhizal]] fungi.{{Cite book |url=https://link.springer.com/book/10.1007/978-981-10-4115-0 |title=Arbuscular Mycorrhizas and Stress Tolerance of Plants |publisher=Springer Singapore |year=2017 |isbn=978-981-10-4115-0 |editor-last=Wu |editor-first=Qiang-Sheng |edition=1st |pages=1 |language=en |doi=10.1007/978-981-10-4115-0}} The association is normally [[Mutualism (biology)|mutualistic]]. In particular species, or in particular circumstances, mycorrhizae may have a [[Parasitism|parasitic]] association with host plants.{{cite journal |last1=Johnson |first1=N. C. |last2=Graham |first2=J. H. |last3=Smith |first3=F. A. |title=Functioning of mycorrhizal associations along the mutualism–parasitism continuum |journal=[[New Phytologist]] |date=1997 |doi=10.1046/j.1469-8137.1997.00729.x |volume=135 |issue=4 |pages=575–585|s2cid=42871574 |doi-access=free }} [11] => [12] => == Definition == [13] => [14] => A mycorrhiza is a symbiotic association between a green plant and a fungus. The plant makes organic molecules by [[photosynthesis]] and supplies them to the fungus in the form of sugars or lipids, while the fungus supplies the plant with water and mineral nutrients, such as [[phosphorus]], taken from the soil. Mycorrhizas are located in the roots of vascular plants, but mycorrhiza-like associations also occur in [[bryophytes]]{{cite journal |date=2005 |first1=I. |last1=Kottke |first2=M. |last2=Nebel |title=The evolution of mycorrhiza‐like associations in liverworts: An update |journal=New Phytologist |volume=167 |issue= 2 |pages=330–334 |doi=10.1111/j.1469-8137.2005.01471.x |pmid=15998388|doi-access=free }} and there is fossil evidence that early land plants that lacked roots formed arbuscular mycorrhizal associations. Most plant species form mycorrhizal associations, though some families like [[Brassicaceae]] and [[Chenopodiaceae]] cannot. Different forms for the association are detailed in the next section. The most common is the [[Arbuscular mycorrhiza|arbuscular type]] that is present in 70% of plant species, including many crop plants such as cereals and legumes.{{cite book |last1=Fortin |first1=J. André |display-authors=etal |title=Les Mycorhizes |date=2015 |publisher=Inra |location=Versaillles |isbn=978-2-7592-2433-3 |page=10 |edition=second}} [15] => [16] => == Evolution == [17] => [18] => Fossil and genetic evidence indicate that mycorrhizae are ancient, potentially as old as the [[Timeline of plant evolution#Ordovician flora|terrestrialization of plants]]. Genetic evidence indicates that all land plants share a single common ancestor,{{Cite journal |last1=Harris |first1=Brogan J. |last2=Clark |first2=James W. |last3=Schrempf |first3=Dominik |last4=Szöllősi |first4=Gergely J. |last5=Donoghue |first5=Philip C. J. |last6=Hetherington |first6=Alistair M. |last7=Williams |first7=Tom A. |date=2022-09-29 |title=Divergent evolutionary trajectories of bryophytes and tracheophytes from a complex common ancestor of land plants |journal=Nature Ecology & Evolution |volume=6 |issue=11 |pages=1634–1643 |doi=10.1038/s41559-022-01885-x |pmc=9630106 |pmid=36175544}} which appears to have quickly adopted mycorrhizal symbiosis, and research suggests that proto-mycorrhizal fungi were a key factor enabling plant terrestrialization.{{Cite journal |last1=Puginier |first1=Camille |last2=Keller |first2=Jean |last3=Delaux |first3=Pierre-Marc |date=2022-08-29 |title=Plant–microbe interactions that have impacted plant terrestrializations |url=https://academic.oup.com/plphys/article/190/1/72/6596610 |journal=Plant Physiology |volume=190 |issue=1 |pages=72–84 |doi=10.1093/plphys/kiac258 |pmid=35642902 |pmc=9434271 }} The 400 million year old [[Rhynie chert]] contains an assemblage of fossil plants preserved in sufficient detail that arbuscular mycorrhizae have been observed in the stems of [[Aglaophyton|''Aglaophyton major'']], giving a lower bound for how late mycorrhizal symbiosis may have developed. Ectomycorrhizae developed substantially later, during the [[Jurassic]] period, while most other modern mycorrhizal families, including orchid and erchoid mycorrhizae, date to the period of [[Flowering plant#Cretaceous|angiosperm radiation]] in the [[Cretaceous]] period.{{Cite journal |last1=Miyauchi |first1=Shingo |last2=Kiss |first2=Enikő |last3=Kuo |first3=Alan |last4=Drula |first4=Elodie |last5=Kohler |first5=Annegret |last6=Sánchez-García |first6=Marisol |last7=Morin |first7=Emmanuelle |last8=Andreopoulos |first8=Bill |last9=Barry |first9=Kerrie W. |last10=Bonito |first10=Gregory |last11=Buée |first11=Marc |last12=Carver |first12=Akiko |last13=Chen |first13=Cindy |last14=Cichocki |first14=Nicolas |last15=Clum |first15=Alicia |display-authors=3 |date=2020 |title=Large-scale genome sequencing of mycorrhizal fungi provides insights into the early evolution of symbiotic traits |journal=Nature Communications |volume=11 |issue=1 |pages=5125 |doi=10.1038/s41467-020-18795-w |pmc=7550596 |pmid=33046698 |bibcode=2020NatCo..11.5125M}} There is genetic evidence that the symbiosis between [[legume]]s and [[nitrogen-fixing bacteria]] is an extension of mycorrhizal symbiosis.{{Cite journal |last1=Provorov |first1=N. A. |last2=Shtark |first2=O. Yu |last3=Dolgikh |first3=E. A. |date=2016 |title=[Evolution of nitrogen-fixing symbioses based on the migration of bacteria from mycorrhizal fungi and soil into the plant tissues] |url=https://pubmed.ncbi.nlm.nih.gov/30024143 |journal=Zhurnal Obshchei Biologii |volume=77 |issue=5 |pages=329–345 |pmid=30024143}} The modern distribution of mycorrhizal fungi appears to reflect an increasing complexity and competition in root morphology associated with the dominance of angiosperms in the [[Cenozoic |Cenozoic Era]], characterized by complex ecological dynamics between species.{{Cite journal |last1=Brundrett |first1=Mark C. |last2=Tedersoo |first2=Leho |date=2018 |title=Evolutionary history of mycorrhizal symbioses and global host plant diversity |journal=New Phytologist |volume=220 |issue=4 |pages=1108–1115 |doi=10.1111/nph.14976 |pmid=29355963 |doi-access=free }} [19] => [20] => == Types== [21] => [22] => Mycorrhizas are commonly divided into ''ectomycorrhizas'' and ''endomycorrhizas''. The two types are differentiated by the fact that the hyphae of ectomycorrhizal fungi do not penetrate individual [[cell (biology)|cells]] within the root, while the [[hypha]]e of endomycorrhizal fungi penetrate the cell wall and [[wikt:invaginate|invaginate]] the [[cell membrane]].Harley, J. L.; Smith, S. E. 1983. Mycorrhizal symbiosis (1st ed.). Academic Press, London.Allen, Michael F. 1991. The ecology of mycorrhizae. Cambridge University Press, Cambridge. Endomycorrhiza includes ''arbuscular'', ''ericoid'', and ''orchid mycorrhiza'', while ''arbutoid mycorrhizas'' can be classified as ''ectoendomycorrhizas''. ''Monotropoid'' mycorrhizas form a special category. [23] => [24] => ===Ectomycorrhiza=== [25] => [26] => [[File:Grib skov.jpg |thumb |[[Beech]] is [[ectomycorrhiza]]l ]] [27] => [[File:Raudonvirsis1-vi.jpg |thumb |''[[Leccinum aurantiacum]]'', an [[#Ectomycorrhiza|ectomycorrhizal]] fungus]] [28] => [29] => {{Main|Ectomycorrhiza}} [30] => [31] => Ectomycorrhizas, or EcM, are symbiotic associations between the roots of around 10% of plant families, mostly woody plants including the [[Betulaceae|birch]], [[Dipterocarpaceae|dipterocarp]], [[Myrtaceae|eucalyptus]], [[Fagaceae|oak]], [[Pinaceae|pine]], and [[Rosaceae|rose]] families, [[Orchidaceae#Ecology|orchids]],{{cite web |url=http://esciencenews.com/articles/2011/07/12/orchids.and.fungi.an.unexpected.case.symbiosis |title=Orchids and fungi: An unexpected case of symbiosis |date=July 12, 2011 |publisher=American Journal of Botany |access-date=24 July 2012 |archive-url=https://web.archive.org/web/20110715013341/http://esciencenews.com/articles/2011/07/12/orchids.and.fungi.an.unexpected.case.symbiosis |archive-date=2011-07-15 |url-status=live }} and fungi belonging to the [[Basidiomycota]], [[Ascomycota]], and [[Zygomycota]]. Some EcM fungi, such as many ''[[Leccinum]]'' and ''[[Suillus]]'', are symbiotic with only one particular genus of plant, while other fungi, such as the ''[[Amanita]]'', are generalists that form mycorrhizas with many different plants. An individual tree may have 15 or more different fungal EcM partners at one time. Thousands of ectomycorrhizal fungal species exist, hosted in over 200 genera. A recent study has conservatively estimated global ectomycorrhizal fungal species richness at approximately 7750 species, although, on the basis of estimates of knowns and unknowns in macromycete diversity, a final estimate of ECM species richness would probably be between 20,000 and 25,000.{{cite journal |last1=Rinaldi |first1=A. C. |last2=Comandini |first2=O. |last3=Kuyper |first3=T. W. |date=2008 |title=Ectomycorrhizal fungal diversity: separating the wheat from the chaff |journal=Fungal Diversity |volume=33 |pages=1–45 |url=http://www.fungaldiversity.org/fdp/sfdp/33-1.pdf |access-date=2011-05-23 |archive-url=https://web.archive.org/web/20110724163606/http://www.fungaldiversity.org/fdp/sfdp/33-1.pdf |archive-date=2011-07-24 |url-status=live }} [32] => [33] => Ectomycorrhizas consist of a hyphal sheath, or mantle, covering the root tip and a [[Hartig net]] of hyphae surrounding the plant cells within the root [[Cortex (botany)|cortex]]. In some cases the hyphae may also penetrate the plant cells, in which case the mycorrhiza is called an ectendomycorrhiza. Outside the root, [[ectomycorrhizal extramatrical mycelium]] forms an extensive network within the soil and [[leaf litter]]. [34] => [35] => Nutrients can be shown to move between different plants through the fungal network. Carbon has been shown to move from [[Betula papyrifera|paper birch]] seedlings into adjacent [[Coast Douglas-fir|Douglas-fir]] seedlings, although not conclusively through a common mycorrhizal network,{{Cite journal |last1=Karst |first1=Justine |last2=Jones |first2=Melanie D. |last3=Hoeksema |first3=Jason D. |date=2023-02-13 |title=Positive citation bias and overinterpreted results lead to misinformation on common mycorrhizal networks in forests |url=https://www.nature.com/articles/s41559-023-01986-1 |journal=Nature Ecology & Evolution |language=en |volume=7 |issue=4 |pages=501–511 |doi=10.1038/s41559-023-01986-1 |pmid=36782032 |s2cid=256845005 |issn=2397-334X}} thereby promoting [[Ecological succession|succession]] in [[ecosystem]]s.{{cite journal |last1=Simard |first1=Suzanne W. |last2=Perry |first2=David A. |last3=Jones |first3=Melanie D. |last4=Myrold |first4=David D. |last5=Durall |first5=Daniel M. |last6=Molina |first6=Randy |name-list-style=amp |title=Net transfer of carbon between ectomycorrhizal tree species in the field |journal=Nature |volume=388 |issue=6642 |date=1997 |pages=579–582 |doi=10.1038/41557 |bibcode=1997Natur.388..579S |s2cid=4423207 |doi-access=free }} The ectomycorrhizal fungus ''[[Laccaria bicolor]]'' has been found to lure and kill [[springtail]]s to obtain nitrogen, some of which may then be transferred to the mycorrhizal host plant. In a study by Klironomos and Hart, [[Eastern White Pine]] inoculated with ''L. bicolor'' was able to derive up to 25% of its nitrogen from springtails.[https://archive.today/20120710035451/http://findarticles.com/p/articles/mi_m1200/is_14_159/ai_104730213/ Fungi kill insects and feed host plants] BNET.com{{cite journal |last1=Klironomos |first1=J. N. |last2=Hart |first2=M. M. |date=2001 |title=Animal nitrogen swap for plant carbon |journal=Nature |volume=410 |issue=6829 |pages=651–652 |doi=10.1038/35070643 |pmid=11287942 |bibcode=2001Natur.410..651K |s2cid=4418192 }} When compared with non-mycorrhizal fine roots, ectomycorrhizae may contain very high concentrations of trace elements, including toxic metals (cadmium, silver) or chlorine.{{cite journal |last1=Cejpková |first1=J. |last2=Gryndler |first2=M. |last3=Hršelová |first3=H. |last4=Kotrba |first4=P. |last5=Řanda |first5=Z. |last6=Greňová |first6=I. |last7=Borovička |first7=J. |title=Bioaccumulation of heavy metals, metalloids, and chlorine in ectomycorrhizae from smelter-polluted area |journal=Environmental Pollution |volume=218 |pages=176–185 |doi=10.1016/j.envpol.2016.08.009 |pmid=27569718 |year=2016}} [36] => [37] => The first genomic sequence for a representative of symbiotic fungi, the ectomycorrhizal basidiomycete ''L. bicolor'', was published in 2008.{{cite journal |last1=Martin |first1=F. |date=2008 |title=The genome of ''Laccaria bicolor'' provides insights into mycorrhizal symbiosis |doi=10.1038/nature06556 |journal=Nature |volume=452 |issue=7183 |pages=88–92 |pmid=18322534 |first2=A. |last3=Ahrén |first3=D. |last4=Brun |first4=A. |last5=Danchin |first5=E. G. J. |last6=Duchaussoy |first6=F. |last7=Gibon |first7=J. |last8=Kohler |first8=A. |last9=Lindquist |first9=E. |display-authors=2 |last2=Aerts |bibcode=2008Natur.452...88M |url=https://nootropicsfrontline.com/wp-content/uploads/2021/07/wiki_martin2008.pdf |doi-access=free }} An expansion of several multigene families occurred in this fungus, suggesting that adaptation to symbiosis proceeded by gene duplication. Within lineage-specific genes those coding for symbiosis-regulated secreted proteins showed an up-regulated expression in ectomycorrhizal root tips suggesting a role in the partner communication. ''L. bicolor'' is lacking enzymes involved in the degradation of plant cell wall components (cellulose, hemicellulose, pectins and pectates), preventing the symbiont from degrading host cells during the root colonisation. By contrast, ''L. bicolor'' possesses expanded multigene families associated with hydrolysis of bacterial and microfauna polysaccharides and proteins. This genome analysis revealed the dual [[saprotrophic]] and [[biotrophic]] lifestyle of the mycorrhizal fungus that enables it to grow within both soil and living plant roots. Since then, the genomes of many other ectomycorrhizal fungal species have been sequenced further expanding the study of gene families and evolution in these organisms.{{Cite journal |last1=Miyauchi |first1=Shingo |last2=Kiss |first2=Enikő |last3=Kuo |first3=Alan |last4=Drula |first4=Elodie |last5=Kohler |first5=Annegret |last6=Sánchez-García |first6=Marisol |last7=Morin |first7=Emmanuelle |last8=Andreopoulos |first8=Bill |last9=Barry |first9=Kerrie W. |last10=Bonito |first10=Gregory |last11=Buée |first11=Marc |last12=Carver |first12=Akiko |last13=Chen |first13=Cindy |last14=Cichocki |first14=Nicolas |last15=Clum |first15=Alicia |date=2020-10-12 |title=Large-scale genome sequencing of mycorrhizal fungi provides insights into the early evolution of symbiotic traits |journal=Nature Communications |language=en |volume=11 |issue=1 |pages=5125 |doi=10.1038/s41467-020-18795-w |issn=2041-1723 |pmc=7550596 |pmid=33046698|bibcode=2020NatCo..11.5125M }} [38] => [39] => ====Arbutoid mycorrhiza==== [40] => [41] => This type of mycorrhiza involves plants of the Ericaceae subfamily [[Arbutoideae]]. It is however different from ericoid mycorrhiza and resembles ectomycorrhiza, both functionally and in terms of the fungi involved.{{cite journal |last=Brundrett |first=Mark |title=Diversity and classification of mycorrhizal associations |journal=Biological Reviews |publisher=Wiley |volume=79 |issue=3 |year=2004 |issn=1464-7931 |doi=10.1017/s1464793103006316 |pages=473–495|pmid=15366760 |s2cid=33371246 }} It differs from ectomycorrhiza in that some hyphae actually penetrate into the root cells, making this type of mycorrhiza an ''ectendomycorrhiza''.{{cite news |url=https://www.business-standard.com/article/pti-stories/some-plants-may-depend-more-on-friendly-fungi-than-own-leaves-study-119102900751_1.html |title=Some plants may depend more on friendly fungi than own leaves: Study |work=Business Standard |date=20 October 2019 |agency=Press Trust of India }} [42] => [43] => ===Endomycorrhiza=== [44] => [45] => Endomycorrhizas are variable and have been further classified as arbuscular, ericoid, arbutoid, monotropoid, and orchid mycorrhizas.{{Cite book |last1=Peterson |first1=R. L. |first2=H. B. |last2=Massicotte |name-list-style=amp |first3=L. H. |last3=Melville |date=2004 |url=http://pubs.nrc-cnrc.gc.ca/eng/books/books/9780660190877.html |title=Mycorrhizas: anatomy and cell biology |publisher=National Research Council Research Press |isbn=978-0-660-19087-7 |url-status=dead |archive-url=https://web.archive.org/web/20071225163327/http://pubs.nrc-cnrc.gc.ca/eng/books/books/9780660190877.html |archive-date=2007-12-25 }} [46] => [47] => ====Arbuscular mycorrhiza==== [48] => [49] => {{Main|Arbuscular mycorrhiza}} [50] => [51] => [[File:Wheat field.jpg|thumb|upright|[[Wheat]] has [[arbuscular mycorrhiza]]. ]] [52] => [53] => [[Arbuscular mycorrhiza]]s, (formerly known as vesicular-arbuscular mycorrhizas), have hyphae that penetrate plant cells, producing dichotomously branching invaginations (arbuscules) as a means of nutrient exchange. Often, balloon-like storage structures, termed vesicles, are also produced. In this interaction, fungal [[hyphae]] do not in fact penetrate the [[protoplast]] (i.e. the interior of the cell), but invaginate the [[cell membrane]], creating a so-called peri-arbuscular membrane. The structure of the arbuscules greatly increases the contact surface area between the hypha and the host cell [[cytoplasm]] to facilitate the transfer of nutrients between them. Arbuscular mycorrhizas are fungi that are obligate biotrophs, meaning that they use the plant host for both growth and reproduction.{{Cite journal |last1=Lanfranco |first1=Luisa |last2=Bonfante |first2=Paola |last3=Genre |first3=Andrea |date=2016-12-23 |editor-last=Heitman |editor-first=Joseph |editor2-last=Howlett |editor2-first=Barbara J. |title=The Mutualistic Interaction between Plants and Arbuscular Mycorrhizal Fungi |url=https://journals.asm.org/doi/10.1128/microbiolspec.FUNK-0012-2016 |journal=Microbiology Spectrum |language=en |volume=4 |issue=6 |pages=4.6.14 |doi=10.1128/microbiolspec.FUNK-0012-2016 |pmid=28087942 |hdl=2318/1627235 |issn=2165-0497|hdl-access=free }} Twenty percent of the photosynthetic products made by the plant host are consumed by the fungi, the transfer of carbon from the terrestrial host plant is then exchanged by equal amounts of phosphate from the fungi to the plant host.{{Cite journal |last1=Kiers |first1=E. Toby |last2=Duhamel |first2=Marie |last3=Beesetty |first3=Yugandhar |last4=Mensah |first4=Jerry A. |last5=Franken |first5=Oscar |last6=Verbruggen |first6=Erik |last7=Fellbaum |first7=Carl R. |last8=Kowalchuk |first8=George A. |last9=Hart |first9=Miranda M. |last10=Bago |first10=Alberto |last11=Palmer |first11=Todd M. |last12=West |first12=Stuart A. |last13=Vandenkoornhuyse |first13=Philippe |last14=Jansa |first14=Jan |last15=Bücking |first15=Heike |date=2011-08-12 |title=Reciprocal Rewards Stabilize Cooperation in the Mycorrhizal Symbiosis |url=https://www.science.org/doi/10.1126/science.1208473 |journal=Science |language=en |volume=333 |issue=6044 |pages=880–882 |doi=10.1126/science.1208473 |pmid=21836016 |bibcode=2011Sci...333..880K |s2cid=44812991 |issn=0036-8075}} [54] => [55] => Arbuscular mycorrhizas are formed only by fungi in the [[Division (mycology)|division]] [[Glomeromycota]]. Fossil evidence and DNA sequence analysis{{cite journal |last1=Simon |first1=L. |last2=Bousquet |first2=J. |last3=Lévesque |first3=R. C. |last4=Lalonde |first4=M. |date=1993 |title=Origin and diversification of endomycorrhizal fungi and coincidence with vascular land plants |journal=Nature |volume=363 |issue=6424 |pages=67–69 |doi=10.1038/363067a0 |bibcode=1993Natur.363...67S |s2cid=4319766 }} suggest that this mutualism appeared [[Devonian|400-460 million years ago]], when the first plants were colonizing land. Arbuscular mycorrhizas are found in 85% of all plant families, and occur in many crop species. The hyphae of arbuscular mycorrhizal fungi produce the glycoprotein [[glomalin]], which may be one of the major stores of carbon in the soil.{{Cite web |url=https://phys.org/news/2019-11-fungi-climate.html |title=Plants and fungi together could slow climate change |last=International Institute for Applied Systems Analysis |date=2019-11-07 |website=phys.org -us |access-date=2019-11-12}} Arbuscular mycorrhizal fungi have (possibly) been asexual for many millions of years and, unusually, individuals can contain many genetically different nuclei (a phenomenon called [[heterokaryosis]]).{{cite journal |last1=Hijri |first1=M. |last2=Sanders |first2=I. R. |date=2005 |title=Low gene copy number shows that arbuscular mycorrhizal fungi inherit genetically different nuclei |doi=10.1038/nature03069 |journal=Nature |volume=433 |issue=7022 |pages=160–163 |pmid=15650740 |bibcode=2005Natur.433..160H |s2cid=4416663 }} [56] => [57] => ====Ericoid mycorrhiza==== [58] => [59] => [[File:Ericoid mycorrhizal fungus.jpg|thumb|An [[ericoid]] mycorrhizal fungus isolated from ''[[Woollsia pungens]]''{{cite journal |last1=Midgley |first1=DJ |last2=Chambers |first2=SM |last3=Cairney |first3=J. W. G. |date=2002 |title=Spatial distribution of fungal endophyte genotypes in a Woollsia pungens (Ericaceae) root system |doi=10.1071/BT02020 |journal=Australian Journal of Botany |volume=50 |issue=5 |pages=559–565 }}]] [60] => [61] => {{Main |Ericoid mycorrhiza}} [62] => [63] => [[Ericoid mycorrhiza]]s are the third of the three more ecologically important types. They have a simple intraradical (growth in cells) phase, consisting of dense coils of hyphae in the outermost layer of root cells. There is no periradical phase and the extraradical phase consists of sparse hyphae that don't extend very far into the surrounding soil. They might form sporocarps (probably in the form of small cups), but their reproductive biology is poorly understood. [64] => [65] => Ericoid mycorrhizas have also been shown to have considerable [[saprotrophic]] capabilities, which would enable plants to receive nutrients from not-yet-decomposed materials via the decomposing actions of their [[ericoid]] partners.{{Cite journal |last1=Read |first1=D. J. |name-list-style=amp |first2=J. |last2=Perez-Moreno |title=Mycorrhizas and nutrient cycling in ecosystems—a journey towards relevance? |journal=New Phytologist |date=2003 |volume=157 |issue=3 |pages=475–492 |doi=10.1046/j.1469-8137.2003.00704.x |pmid=33873410 |doi-access=free }} [66] => [67] => ====Orchid mycorrhiza==== [68] => [69] => {{Main |Orchid mycorrhiza}} [70] => [71] => All [[Orchidaceae|orchids]] are [[myco-heterotrophy|myco-heterotrophic]] at some stage during their lifecycle, meaning that they can survive only if they form [[orchid mycorrhiza]]s with basidiomycete fungi.{{citation needed |date=November 2014}} Their hyphae penetrate into the root cells and form pelotons (coils) for nutrient exchange.{{citation needed |date=November 2014}} [72] => [73] => ====Monotropoid mycorrhiza==== [74] => [75] => {{Main |Myco-heterotrophy}} [76] => [77] => This type of mycorrhiza occurs in the subfamily [[Monotropoideae]] of the [[Ericaceae]], as well as several genera in the [[Orchidaceae]]. These plants are [[heterotrophic]] or [[mixotrophic]] and derive their carbon from the fungus partner. This is thus a non-mutualistic, [[Parasitism|parasitic]] type of mycorrhizal symbiosis.{{citation needed |date=November 2014}} [78] => [79] => ==Mutualist dynamics== [80] => [81] => [[File:Mycorrhizal network.svg |thumb|upright=1.35 |Nutrient exchanges and communication between a mycorrhizal fungus and plants.]] [82] => [83] => Mycorrhizal fungi form a [[Mutualism (biology)|mutualistic]] relationship with the roots of most plant species. In such a relationship, both the plants themselves and those parts of the roots that host the fungi, are said to be mycorrhizal. Relatively few of the mycorrhizal relationships between plant species and fungi have been examined to date, but 95% of the plant families investigated are predominantly mycorrhizal either in the sense that most of their species associate beneficially with mycorrhizae, or are absolutely dependent on mycorrhizae. The [[Orchidaceae]] are notorious as a family in which the absence of the correct mycorrhizae is fatal even to germinating seeds.{{Cite book |last=Trappe |first=J. M. |date=1987 |chapter=Phylogenetic and ecologic aspects of mycotrophy in the angiosperms from an evolutionary standpoint |title=Ecophysiology of VA Mycorrhizal Plants |editor-last=Safir |editor-first=G. R. |publisher=CRC Press |location=Florida }} [84] => [85] => Recent research into [[ectomycorrhizal]] plants in [[boreal forests]] has indicated that mycorrhizal fungi and plants have a relationship that may be more complex than simply mutualistic. This relationship was noted when mycorrhizal fungi were unexpectedly found to be hoarding nitrogen from plant roots in times of nitrogen scarcity. Researchers argue that some mycorrhizae distribute nutrients based upon the environment with surrounding plants and other mycorrhizae. They go on to explain how this updated model could explain why mycorrhizae do not alleviate plant nitrogen limitation, and why plants can switch abruptly from a mixed strategy with both mycorrhizal and nonmycorrhizal roots to a purely mycorrhizal strategy as soil nitrogen availability declines.{{cite journal |last1=Franklin |first1=O. |last2=Näsholm |first2=T. |last3=Högberg |first3=P. |last4=Högberg |first4=M. N. |title=Forests trapped in nitrogen limitation - an ecological market perspective on ectomycorrhizal symbiosis |journal=New Phytologist |date=2014 |volume=203 |issue=2 |pages=657–666 |pmid=24824576 |doi=10.1111/nph.12840 |pmc=4199275}} It has also been suggested that evolutionary and phylogenetic relationships can explain much more variation in the strength of mycorrhizal mutualisms than ecological factors. [86] => [87] => [[File:Mutualistic mycorrhiza en.svg |thumb|Within mycorrhiza, the plant gives carbohydrates (products of photosynthesis) to the fungus, while the fungus gives the plant water and minerals.]] [88] => [89] => ===Sugar-water/mineral exchange=== [90] => [91] => [[File:Mycorrhiza.svg|thumb|In this mutualism, fungal hyphae (E) increase the surface area of the root and uptake of key nutrients while the plant supplies the fungi with fixed carbon (A=root cortex, B=root epidermis, C=arbuscle, D=vesicle, F=root hair, G=nuclei).]] [92] => [93] => The mycorrhizal mutualistic association provides the fungus with relatively constant and direct access to [[carbohydrate]]s, such as [[glucose]] and [[sucrose]].{{cite journal |last=Harrison |first=M. J. |date=2005 |title=Signaling in the arbuscular mycorrhizal symbiosis |journal=Annu Rev Microbiol |volume=59 |pages=19–42 |pmid=16153162 |doi=10.1146/annurev.micro.58.030603.123749}} The carbohydrates are translocated from their source (usually leaves) to root tissue and on to the plant's fungal partners. In return, the plant gains the benefits of the [[mycelium]]'s higher absorptive capacity for water and mineral nutrients, partly because of the large surface area of fungal hyphae, which are much longer and finer than plant [[root hair]]s, and partly because some such fungi can mobilize soil minerals unavailable to the plants' roots. The effect is thus to improve the plant's mineral absorption capabilities.{{cite journal |last1=Selosse |first1=M. A. |last2=Richard |first2=F. |last3=He |first3=X. |last4=Simard |first4=S. W. |date= 2006 |title=Mycorrhizal networks: des liaisons dangereuses? |journal=Trends in Ecology and Evolution |volume=21 |pages=621–628 |pmid=16843567 |doi=10.1016/j.tree.2006.07.003 |issue=11}} [94] => [95] => Unaided plant roots may be unable to take up [[nutrient]]s that are chemically or physically [[Immobilization (soil science)|immobilised]]; examples include [[phosphate]] [[ions]] and [[micronutrient]]s such as iron. One form of such immobilization occurs in soil with high [[clay]] content, or soils with a strongly [[pH|basic pH]]. The [[mycelium]] of the mycorrhizal fungus can, however, access many such nutrient sources, and make them available to the plants they colonize.{{cite journal |last1=Li |first1=H. |last2=Smith |first2=S. E. |last3=Holloway |first3=R. E. |last4=Zhu |first4=Y. |last5=Smith |first5=F. A. |date=2006 |title=Arbuscular mycorrhizal fungi contribute to phosphorus uptake by wheat grown in a phosphorus-fixing soil even in the absence of positive growth responses |journal=New Phytologist |volume=172 |pages=536–543 |pmid=17083683 |doi=10.1111/j.1469-8137.2006.01846.x |issue=3 |doi-access=free}} Thus, many plants are able to obtain phosphate without using soil as a source. Another form of immobilisation is when nutrients are locked up in organic matter that is slow to decay, such as wood, and some mycorrhizal fungi act directly as decay organisms, mobilising the nutrients and passing some onto the host plants; for example, in some [[dystrophic]] forests, large amounts of phosphate and other nutrients are taken up by mycorrhizal [[hypha]]e acting directly on [[leaf litter]], bypassing the need for soil uptake.{{cite book |last=Hogan |first=C.M. |date=2011 |chapter-url=http://www.eoearth.org/article/Phosphate?topic=49557 |chapter=Phosphate |title=Encyclopedia of Earth |editor1=Jorgensen, A. |editor2=Cleveland, C.J. |publisher=National Council for Science and the Environment. |location=Washington DC |archive-url=https://web.archive.org/web/20121025180158/http://www.eoearth.org/article/Phosphate?topic=49557 |archive-date=2012-10-25 }} ''[[Inga alley cropping]]'', an [[agroforestry]] technique proposed as an alternative to [[slash and burn]] rainforest destruction,{{cite web |last=Elkan |first=D. |title=Slash-and-burn farming has become a major threat to the world's rainforest |work=[[The Guardian]] |date=21 April 2004 |url=https://www.theguardian.com/society/2004/apr/21/environment.environment }} relies upon mycorrhiza within the root system of species of ''[[Inga]]'' to prevent the rain from washing [[phosphorus]] out of the soil.{{cite web |work=rainforestsaver.org |url=http://www.rainforestsaver.org/what-is-it-all-about/what-is-inga-alley-cropping/ |title=What is Inga alley cropping? |archive-url=https://web.archive.org/web/20111101062913/http://www.rainforestsaver.org/what-is-it-all-about/what-is-inga-alley-cropping |archive-date=2011-11-01 }} [96] => [97] => In some more complex relationships, mycorrhizal fungi do not just collect immobilised soil nutrients, but connect individual plants together by [[mycorrhizal networks]] that transport water, carbon, and other nutrients directly from plant to plant through underground hyphal networks.{{cite journal |last1=Simard |first1=S.W. |author2=Beiler, K.J. |author3=Bingham, M.A. |author4=Deslippe, J.R. |author5=Philip, L.J. |author6=Teste, F.P. |title=Mycorrhizal networks: mechanisms, ecology and modelling. |journal=Fungal Biology Reviews |date=April 2012 |volume=26 |issue=1 |pages=39–60 |doi=10.1016/j.fbr.2012.01.001 }} [98] => [99] => ''[[Suillus tomentosus]]'', a [[basidiomycete]] fungus, produces specialized structures known as tuberculate ectomycorrhizae with its plant host [[lodgepole pine]] (''Pinus contorta'' var. ''latifolia''). These structures have been shown to host [[nitrogen fixation|nitrogen fixing]] [[bacteria]] which contribute a significant amount of [[nitrogen]] and allow the pines to colonize nutrient-poor sites. [100] => [101] => ===Mechanisms=== [102] => [103] => The mechanisms by which mycorrhizae increase absorption include some that are physical and some that are chemical. Physically, most mycorrhizal mycelia are much smaller in diameter than the smallest root or root hair, and thus can explore soil material that roots and root hairs cannot reach, and provide a larger surface area for absorption. Chemically, the cell membrane chemistry of fungi differs from that of plants. For example, they may secrete [[organic acid]]s that dissolve or [[Chelation|chelate]] many ions, or release them from minerals by [[ion exchange]].{{cite book |chapter=Overview of Mycorrhizal Symbioses |title=Principles and Applications of Soil Microbiology |isbn=978-0-13-094117-6 |chapter-url=http://cropsoil.psu.edu/sylvia/mycorrhiza.htm |archive-url=https://web.archive.org/web/20100623051447/http://cropsoil.psu.edu/sylvia/mycorrhiza.htm|archive-date= June 23, 2010|last1=Sylvia |first1=David M. |last2=Fuhrmann |first2=Jeffry J. |last3=Hartel |first3=Peter G. |last4=Zuberer |first4=David A. |year=2005 |publisher=Pearson Prentice Hall }} Mycorrhizae are especially beneficial for the plant partner in nutrient-poor soils.{{cite web |url=http://www.biologie.uni-hamburg.de/b-online/e33/33b.htm |title=Botany online: Interactions - Plants - Fungi - Parasitic and Symbiotic Relations - Mycorrhiza |publisher=Biologie.uni-hamburg.de |access-date=2010-09-30 |url-status=dead |archive-url=https://web.archive.org/web/20110606050759/http://www.biologie.uni-hamburg.de/b-online/e33/33b.htm |archive-date=2011-06-06 }} [104] => [105] => ===Disease, drought and salinity resistance and its correlation to mycorrhizae=== [106] => [107] => Mycorrhizal plants are often more resistant to diseases, such as those caused by microbial soil-borne [[pathogen]]s. These associations have been found to assist in plant defense both above and belowground. Mycorrhizas have been found to excrete enzymes that are toxic to soil borne organisms such as nematodes.{{cite journal |last1=Azcón-Aguilar |first1=C. |last2=Barea |first2=J. M. |title=Arbuscular mycorrhizas and biological control of soil-borne plant pathogens – an overview of the mechanisms involved |journal=Mycorrhiza |date=29 October 1996 |volume=6 |issue=6 |pages=457–464 |doi=10.1007/s005720050147 |s2cid=25190159}} More recent studies have shown that mycorrhizal associations result in a priming effect of plants that essentially acts as a primary immune response. When this association is formed a defense response is activated similarly to the response that occurs when the plant is under attack. As a result of this inoculation, defense responses are stronger in plants with mycorrhizal associations.{{cite journal |last1=Jung |first1=Sabine C. |last2=Martinez-Medina |first2=Ainhoa |last3=Lopez-Raez |first3=Juan A. |last4=Pozo |first4=Maria J. |title=Mycorrhiza-Induced Resistance and Priming of Plant Defenses |journal=J Chem Ecol |date=24 May 2012 |volume=38 |issue=6 |pages=651–664 |doi=10.1007/s10886-012-0134-6 |pmid=22623151 |s2cid=12918193|hdl=10261/344431 |hdl-access=free }} [108] => [[Ecosystem services]] provided by mycorrhizal fungi may depend on the soil microbiome.{{cite journal |last1=Svenningsen |first1=Nanna B |last2=Watts-Williams |first2=Stephanie J |last3=Joner |first3=Erik J |last4=Battini |first4=Fabio |last5=Efthymiou |first5=Aikaterini |last6=Cruz-Paredes |first6=Carla |last7=Nybroe |first7=Ole |last8=Jakobsen |first8=Iver |title=Suppression of the activity of arbuscular mycorrhizal fungi by the soil microbiota |journal=The ISME Journal |date=May 2018 |volume=12 |issue=5 |pages=1296–1307 |doi=10.1038/s41396-018-0059-3 |pmid=29382946 |pmc=5931975 |doi-access=free }} Furthermore, mycorrhizal fungi was significantly correlated with soil physical variable, but only with water level and not with aggregate stability{{cite book |doi=10.1007/1-4020-4447-X_10 |chapter=Disease Resistance in Plants Through Mycorrhizal Fungi Induced Allelochemicals |title=Allelochemicals: Biological Control of Plant Pathogens and Diseases |series=Disease Management of Fruits and Vegetables |year=2006 |last1=Zeng |first1=Ren-Sen |volume=2 |pages=181–192 |isbn=1-4020-4445-3 }}{{cite web |url=https://www.usask.ca/biology/kaminskyj/arctic.html |title=Dr. Susan Kaminskyj: Endorhizal Fungi |publisher=Usask.ca |access-date=2010-09-30 |archive-url=https://web.archive.org/web/20101104000757/http://www.usask.ca/biology/kaminskyj/arctic.html |archive-date=2010-11-04 |url-status=dead }} and can lead also to more resistant to the effects of drought.{{cite web |url=http://aggie-horticulture.tamu.edu/Faculty/davies/research/mycorrhizae.html |title=Dr. Davies Research Page |publisher=Aggie-horticulture.tamu.edu |access-date=2010-09-30 |url-status=dead |archive-url=https://web.archive.org/web/20101019002159/http://aggie-horticulture.tamu.edu/faculty/davies/research/mycorrhizae.html |archive-date=2010-10-19 }}{{Cite journal |last=Lehto |first=Tarja |date=1992 |title=Mycorrhizas and Drought Resistance of ''Picea sitchensis'' (Bong.) Carr. I. In Conditions of Nutrient Deficiency |journal=New Phytologist |volume=122 |issue=4 |pages=661–668 |jstor=2557434 |doi=10.1111/j.1469-8137.1992.tb00094.x |doi-access=free }}{{cite journal |last1=Nikolaou |first1=N. |last2=Angelopoulos |first2=K. |last3=Karagiannidis |first3=N. |date=2003 |title=Effects of Drought Stress on Mycorrhizal and Non-Mycorrhizal Cabernet Sauvignon Grapevine, Grafted Onto Various Rootstocks |journal=Experimental Agriculture |volume=39 |issue=3 |pages=241–252 |doi=10.1017/S001447970300125X |s2cid=84997899 }} Moreover, the significance of mycorrhizal fungi also includes alleviation of salt stress and its beneficial effects on plant growth and productivity. Although salinity can negatively affect mycorrhizal fungi, many reports show improved growth and performance of mycorrhizal plants under salt stress conditions.{{cite journal |last1=Porcel |first1=Rosa |last2=Aroca |first2=Ricardo |last3=Ruiz-Lozano |first3=Juan Manuel |title=Salinity stress alleviation using arbuscular mycorrhizal fungi. A review |journal=Agronomy for Sustainable Development |date=January 2012 |volume=32 |issue=1 |pages=181–200 |doi=10.1007/s13593-011-0029-x |s2cid=8572482 |url=https://hal.archives-ouvertes.fr/hal-00930499/file/hal-00930499.pdf }} [109] => [110] => ===Resistance to insects=== [111] => [112] => Plants connected by mycorrhizal fungi in [[mycorrhizal network]]s can use these underground connections to communicate warning signals.{{cite journal |last1=Babikova |first1=Zdenka |last2=Gilbert |first2=Lucy |last3=Bruce |first3=Toby J. A. |last4=Birkett |first4=Michael |last5=Caulfield |first5=John C. |last6=Woodcock |first6=Christine |last7=Pickett |first7=John A. |last8=Johnson |first8=David |title=Underground signals carried through common mycelial networks warn neighbouring plants of aphid attack |journal=Ecology Letters |date=July 2013 |volume=16 |issue=7 |pages=835–843 |doi=10.1111/ele.12115 |pmid=23656527 }}{{cite journal |last1=Johnson |first1=David |last2=Gilbert |first2=Lucy |title=Interplant signalling through hyphal networks |journal=New Phytologist |date=March 2015 |volume=205 |issue=4 |pages=1448–1453 |doi=10.1111/nph.13115 |pmid=25421970 |doi-access=free }} For example, when a host plant is attacked by an [[aphid]], the plant signals surrounding connected plants of its condition. Both the host plant and those connected to it release [[volatile organic compound]]s that repel aphids and attract [[parasitoid wasp]]s, predators of aphids. This assists the mycorrhizal fungi by conserving its food supply. [113] => [114] => ===Colonization of barren soil=== [115] => Plants grown in sterile [[soil]]s and growth media often perform poorly without the addition of [[spore]]s or hyphae of mycorrhizal fungi to colonise the plant roots and aid in the uptake of soil mineral nutrients.{{cite web |title=Root fungi turn rock into soil |url=http://planetearth.nerc.ac.uk/news/story.aspx?id=470 |website=Planet Earth Online |archive-url =https://web.archive.org/web/20090713022313/http://planetearth.nerc.ac.uk/news/story.aspx?id=470 |archive-date=2009-07-13 |date=3 July 2009 }} The absence of mycorrhizal fungi can also slow plant growth in early succession or on degraded landscapes.{{cite journal |last1=Jeffries |first1=Peter |last2=Gianinazzi |first2=Silvio |last3=Perotto |first3=Silvia |last4=Turnau |first4=Katarzyna |last5=Barea |first5=José-Miguel |title=The contribution of arbuscular mycorrhizal fungi in sustainable maintenance of plant health and soil fertility |journal=Biology and Fertility of Soils |date=January 2003 |volume=37 |issue=1 |pages=1–16 |doi=10.1007/s00374-002-0546-5 |id={{INIST |14498927}} |s2cid=20792333 }} The introduction of alien mycorrhizal plants to nutrient-deficient ecosystems puts indigenous non-mycorrhizal plants at a competitive disadvantage.{{cite book |last=Richardson |first=David M. |title=Ecology and biogeography of Pinus |publisher=Cambridge University Press |location=London |date=2000 |page=336 |isbn=978-0-521-78910-3}} This aptitude to colonize barren soil is defined by the category [[Oligotroph]]. [116] => [117] => ===Resistance to toxicity=== [118] => [119] => Fungi have a protective role for plants rooted in soils with high metal concentrations, such as [[Soil pH|acidic]] and [[Soil contamination|contaminated soils]]. [[Pinus|Pine]] trees inoculated with ''[[Pisolithus tinctorius]]'' planted in several contaminated sites displayed high tolerance to the prevailing contaminant, survivorship and growth. One study discovered the existence of ''[[Suillus luteus]]'' strains with varying tolerance of [[zinc]]. Another study discovered that zinc-tolerant strains of ''[[Suillus bovinus]]'' conferred resistance to plants of ''[[Pinus sylvestris]]''. This was probably due to binding of the metal to the extramatricial [[mycelium]] of the fungus, without affecting the exchange of beneficial substances. [120] => [121] => ==Occurrence of mycorrhizal associations== [122] => [123] => Mycorrhizas are present in 92% of plant families studied (80% of species),{{cite journal |last1=Wang |first1=B. |last2=Qiu |first2=Y.-L. |title=Phylogenetic distribution and evolution of mycorrhizas in land plants |journal=Mycorrhiza |date=July 2006 |volume=16 |issue=5 |pages=299–363 |doi=10.1007/s00572-005-0033-6 |pmid=16845554 |s2cid=30468942 }} with [[arbuscular mycorrhiza]]s being the ancestral and predominant form, and the most prevalent symbiotic association found in the plant kingdom. The structure of arbuscular mycorrhizas has been highly conserved since their first appearance in the fossil record,{{cite journal |last1=Remy |first1=W. |last2=Taylor |first2=T. N. |last3=Hass |first3=H. |last4=Kerp |first4=H. |title=Four hundred-million-year-old vesicular arbuscular mycorrhizae. |journal=Proceedings of the National Academy of Sciences |date=6 December 1994 |volume=91 |issue=25 |pages=11841–11843 |doi=10.1073/pnas.91.25.11841 |pmid=11607500 |pmc=45331 |bibcode=1994PNAS...9111841R |doi-access=free }} with both the development of ectomycorrhizas, and the loss of mycorrhizas, [[convergent evolution|evolving convergently]] on multiple occasions. [124] => [125] => Associations of fungi with the roots of plants have been known since at least the mid-19th century. However early observers simply recorded the fact without investigating the relationships between the two organisms.{{cite journal |last=Rayner |first=M. Cheveley |title=Obligate Symbiosis in ''Calluna vulgaris'' |journal=Annals of Botany |date=1915 |volume=29 |issue=113 |pages=97–134 |doi=10.1093/oxfordjournals.aob.a089540 |url=https://books.google.com/books?id=dMrzAAAAMAAJ&q=Mycorrhiza+Kamienski&pg=PA99}} This symbiosis was studied and described by [[Franciszek Kamieński]] in 1879–1882.{{cite journal |last=Kamieński |first=Franciszek |date=1882 |title=Les organes végétatifs de ''Monotropa hypopitys'' L.". |trans-title=The vegetative organs of ''Monotropa hypopitys'' L. |language=French |journal=Mémoires de la Société nat. Des Sciences naturelles et mathém. De Cherbourg |volume=3 |issue=24 }}. {{cite journal |last1=Berch |first1=S. M. |last2=Massicotte |first2=H. B. |last3=Tackaberry |first3=L. E. |title=Re-publication of a translation of 'The vegetative organs of Monotropa hypopitys L.' published by F. Kamienski in 1882, with an update on Monotropa mycorrhizas |journal=Mycorrhiza |volume=15 |issue=5 |pages=323–32 |date=July 2005 |pmid=15549481 |doi=10.1007/s00572-004-0334-1 |s2cid=3162281 }}{{cite journal |last=Kamieński |first=Franciszek |date=1885 |title=Über die auf Wurzelsymbiose beruhende Ernährung gewisser Bäume durch unterirdische Pilze |trans-title=On the nourishing, via root symbiosis, of certain trees by underground fungi|url=https://babel.hathitrust.org/cgi/pt?id=mdp.39015011935122;view=1up;seq=135 |journal=Berichte der Deutschen Botanischen Gesellschaft |volume=3 |pages=128–145 |language=de}} From p. 129: ''"Der ganze Körper ist also weder Baumwurzel noch Pilz allein, sondern ähnlich wie der Thallus der Flechten, eine Vereinigung zweier verschiedener Wesen zu einem einheitlichen morphologischen Organ, welches vielleicht passend als ''Pilzwurzel'', ''Mycorhiza'' bezeichnet werden kann."'' (The whole body is thus neither tree root nor fungus alone, but similar to the thallus of lichens, a union of two different organisms into a single morphological organ, which can be aptly designated as a "fungus root", a ''mycorrhiza''.) [126] => [127] => == Climate change == [128] => [129] => CO2 released by human activities is causing [[climate change]] and possible damage to mycorrhizae, but the direct effect of an increase in the gas should be to benefit plants and mycorrhizae.{{cite journal |last1=Monz |first1=C. A. |last2=Hunt |first2=H. W. |last3=Reeves |first3=F. B. |last4=Elliott |first4=E. T. |title=The response of mycorrhizal colonization to elevated CO2 and climate change in Pascopyrum smithii and Bouteloua gracilis |journal=Plant and Soil |volume=165 |issue=1 |year=1994 |doi=10.1007/bf00009964 |pages=75–80|s2cid=34893610 }} In Arctic regions, nitrogen and water are harder for plants to obtain, making mycorrhizae crucial to plant growth.{{cite journal |last1=Hobbie |first1=John E. |last2=Hobbie |first2=Erik A. |last3=Drossman |first3=Howard |last4=Conte |first4=Maureen |last5=Weber |first5=J. C. |last6=Shamhart |first6=Julee |last7=Weinrobe |first7=Melissa |display-authors=3 |title=Mycorrhizal fungi supply nitrogen to host plants in Arctic tundra and boreal forests: 15N is the key signal|journal=Canadian Journal of Microbiology |volume=55 |issue=1 |year=2009 |doi=10.1139/w08-127 |pages=84–94|pmid=19190704 |hdl=1912/2902 |hdl-access=free }} Since mycorrhizae tend to do better in cooler temperatures, warming could be detrimental to them.{{cite journal |last1=Heinemeyer |first1=A. |last2=Fitter |first2=A. H. |title=Impact of temperature on the arbuscular mycorrhizal (AM) symbiosis: growth responses of the host plant and its AM fungal partner |journal=Journal of Experimental Botany |volume=55 |issue=396 |date=22 January 2004 |doi=10.1093/jxb/erh049 |pages=525–534|pmid=14739273 |doi-access=free }} Gases such as SO2, NO-x, and O3 produced by human activity may harm mycorrhizae, causing reduction in "[[propagules]], the colonization of roots, degradation in connections between trees, reduction in the mycorrhizal incidence in trees, and reduction in the [[enzyme activity]] of ectomycorrhizal roots."{{Cite journal |last1=Xavier |first1=L. J. |last2=Germida |first2=J. J. |title=Impact of human activities on mycorrhizae |journal=Proceedings of the 8th International Symposium on Microbial Ecology |date=1999 }} [130] => [131] => == Conservation and mapping == [132] => In 2021 the [[Society for the Protection of Underground Networks]] was launched. SPUN is a science-based initiative to map and protect the mycorrhizal networks that regulate the Earth’s climate and ecosystems. The stated goals of SPUN are mapping, protecting, and harnessing mycorrhizal fungi. [133] => [134] => ==See also== [135] => [136] => * [[Effect of climate change on plant biodiversity]] [137] => * [[Endosymbiont]] [138] => * [[Epibiont]], an organism that grows on another life form [139] => * [[Endophyte]] [140] => * [[Epiphyte]] [141] => * [[Epiphytic fungus]] [142] => * [[Mucigel]] [143] => * [[Mycorrhizal fungi and soil carbon storage]] [144] => * [[Mycorrhizal network]] [145] => * [[Rhizobia]] [146] => * [[Suzanne Simard]] [147] => [148] => ==References== [149] => {{Reflist |refs= [150] => [151] => {{cite journal |last1=den Bakker |first1=Henk C. |last2=Zuccarello |first2=G. C. |last3=Kuyper |first3=Th. W. |last4=Noordeloos |first4=M. E. |title=Evolution and host specificity in the ectomycorrhizal genus Leccinum |journal=New Phytologist |date=July 2004 |volume=163 |issue=1 |pages=201–215 |doi=10.1111/j.1469-8137.2004.01090.x |pmid=33873790 |doi-access=free }} [152] => [153] => {{cite journal |last1=Saari |first1=S. K. |last2=Campbell |first2=C. D. |last3=Russell |first3=J. |last4=Alexander |first4=I. J. |last5=Anderson |first5=I. C. |title=Pine microsatellite markers allow roots and ectomycorrhizas to be linked to individual trees |journal=New Phytologist |date=14 October 2004 |volume=165 |issue=1 |pages=295–304 |doi=10.1111/j.1469-8137.2004.01213.x |pmid=15720641 |doi-access=free }} [154] => [155] => {{cite journal |last1=Paul |first1=L. R. |last2=Chapman |first2=B. K. |last3=Chanway |first3=C. P. |title=Nitrogen Fixation Associated with Suillus tomentosus Tuberculate Ectomycorrhizae on Pinus contorta var. latifolia |journal=Annals of Botany |date=1 June 2007 |volume=99 |issue=6 |pages=1101–1109 |doi=10.1093/aob/mcm061 |pmid=17468111 |pmc=3243579 }} [156] => [157] => {{cite journal |journal= Mycorrhiza |volume=5 |pages=181–187 |date=1995 |doi= 10.1007/BF00203335 |title= Heavy metal tolerance by ectomycorrhizal fungi and metal amelioration by Pisolithus tinctorius |first=Paul C.F. |last=Tam |issue=3 |hdl=10722/48503 |s2cid=23867901 |hdl-access=free}} [158] => [159] => {{cite journal |last1=Hoeksema |first1=Jason D. |last2=Bever |first2=James D. |last3=Chakraborty |first3=Sounak |last4=Chaudhary |first4=V. Bala |last5=Gardes |first5=Monique |last6=Gehring |first6=Catherine A. |last7=Hart |first7=Miranda M. |last8=Housworth |first8=Elizabeth Ann |last9=Kaonongbua |first9=Wittaya |last10=Klironomos |first10=John N. |last11=Lajeunesse |first11=Marc J. |last12=Meadow |first12=James |last13=Milligan |first13=Brook G. |last14=Piculell |first14=Bridget J. |last15=Pringle |first15=Anne |last16=Rúa |first16=Megan A. |last17=Umbanhowar |first17=James |last18=Viechtbauer |first18=Wolfgang |last19=Wang |first19=Yen-Wen |last20=Wilson |first20=Gail W. T. |last21=Zee |first21=Peter C. |title=Evolutionary history of plant hosts and fungal symbionts predicts the strength of mycorrhizal mutualism |journal=Communications Biology |volume=1 |issue=1 |date=16 August 2018 |doi=10.1038/s42003-018-0120-9 |page=116|pmid=30271996 |pmc=6123707 }} [160] => }} [161] => [162] => ==External links== [163] => [164] => {{Americana Poster |Mycorriza}} [165] => [166] => * [http://www.mycorrhizas.org International Mycorrhiza Society] International Mycorrhiza Society [167] => * [http://www.ted.com/talks/mohamed_hijri_a_simple_solution_to_the_coming_phosphorus_crisis Mohamed Hijri: A simple solution to the coming phosphorus crisis] video recommending agricultural mycorrhiza use to conserve phosphorus reserves & 85% waste problem @Ted.com [168] => * [http://mycorrhizas.info/index.html Mycorrhizal Associations: The Web Resource] Comprehensive illustrations and lists of mycorrhizal and nonmycorrhizal plants and fungi [169] => * [https://web.archive.org/web/20130412032458/http://www.gmo-safety.eu/science-live/439.mycorrhizas-successful-symbiosis.html Mycorrhizas – a successful symbiosis] Biosafety research into genetically modified barley [170] => * [https://web.archive.org/web/20100616005821/http://mycor.nancy.inra.fr/Wiki/en/index.php/Main_Page MycorWiki] a portal concerned with the biology and ecology of ectomycorrhizal fungi and other forest fungi. [171] => [172] => {{Authority control}} [173] => [174] => [[Category:Plant roots]] [175] => [[Category:Soil biology]] [176] => [[Category:Symbiosis]] [177] => [[Category:Oligotrophs]] [178] => [[Category:Fungus ecology]] [] => )
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Mycorrhiza

Mycorrhiza is a symbiotic association between certain types of fungi and plant roots. This relationship is beneficial for both organisms involved.

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This relationship is beneficial for both organisms involved. The fungi, known as mycorrhizal fungi, live in close proximity to the plant roots and form a network of fine filaments called hyphae. This network enhances the plant's ability to absorb water, minerals, and nutrients from the soil, while the fungi receive carbohydrates and other organic compounds produced by the plant through photosynthesis. The mycorrhizal association has been found to be present in about 90% of all vascular plant species, including trees, crops, and wildflowers. There are two main types of mycorrhiza: ectomycorrhiza and arbuscular mycorrhiza. Ectomycorrhiza is characterized by a fungal sheath that surrounds the root tips, while arbuscular mycorrhiza forms a branching structure within the root cells. Mycorrhizal fungi have numerous benefits for plants. They improve nutrient uptake, especially for elements like phosphorus, nitrogen, and potassium, which may be less available in the soil. The fungi also facilitate water absorption, enhance tolerance to environmental stresses, such as drought or high salinity, and protect against certain pathogens. In return, the plants provide the fungi with sugars and other compounds necessary for their growth and survival. Mycorrhizal associations have a significant impact on ecosystem functioning, soil structure, and nutrient cycling. They play a critical role in promoting plant diversity, soil fertility, and the overall health of ecosystems. This symbiotic relationship has been extensively studied in agriculture, where mycorrhizal inoculants are used to improve crop production, reduce the need for chemical fertilizers, and enhance plant resistance to diseases. The Wikipedia page on Mycorrhiza provides a comprehensive overview of this topic, covering its types, formation, benefits for plants, and ecological importance. It also discusses the role of mycorrhiza in agriculture, forestry, and ecosystem restoration. The page includes information on current research, challenges, and future directions in the field of mycorrhizal studies.

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