Editing Mycorrhiza (section)

===Arbuscular mycorrhiza===

{{Main|Arbuscular mycorrhiza}}

[[File:Wheat field.jpg|thumb|upright|[[Wheat]] has [[arbuscular mycorrhiza]]. ]]

[[Arbuscular mycorrhiza]]s, (formerly known as vesicular-arbuscular mycorrhizas), have hyphae that penetrate plant cells, producing branching, tree-like structures called arbuscules within the plant cells for 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 obligate biotrophs, meaning that they depend upon the plant host for both growth and reproduction; they have lost the ability to sustain themselves by decomposing dead plant material.<ref>{{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 }}</ref> 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.<ref>{{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}}</ref>

Contrasting with the pattern seen in ectomycorrhizae, the species diversity of AMFs is very low, but the diversity of plant hosts is very high; an estimated 78% of all plant species associate with AMFs.<ref name="The functional role of ericoid myco"/> Arbuscular mycorrhizas are formed only by fungi in the [[Division (mycology)|division]] [[Glomeromycota]]. Fossil evidence<ref name="Remy et al."/> and DNA sequence analysis<ref name=simon1993>{{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 }}</ref> 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.<ref name=Wang2006/> The hyphae of arbuscular mycorrhizal fungi produce the glycoprotein [[glomalin]], which may be one of the major stores of carbon in the soil.<ref>{{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}}</ref> 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]]).<ref name="Hijri">{{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 }}</ref>