name = Glomeromycota
regnum = Fungi
phylum_authority = C. Walker & A. Schuessler 2001cite journal | author = Schüßler, A. "et al." |month=Dec| year=2001 | title=A new fungal phlyum, the "Glomeromycota": phylogeny and evolution. | journal=Mycol. Res. | volume=105 | issue=12 | pages=1413–1421 | url=http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=95091 | doi=10.1017/S0953756201005196]
classis = Glomeromycetes
classis_authority = Caval.-Sm., 1998 [cite journal | author=
Cavalier-Smith, T.| year = 1998 | title = A revised six-kingdom system of Life | journal = Biol. Rev. Camb. Philos. Soc.| volume = 73 | pages = 246 (as "Glomomycetes")]
subdivision_ranks = Orders
Glomerales Diversisporales Paraglomerales Archaeosporales
Glomeromycota (informally glomeromycetes) is one of seven currently recognized phyla within the kingdom
author=Hibbett, D.S., "et al."
title=A higher level phylogenetic classification of the "Fungi"
doi=10.1016/j.mycres.2007.03.004] , with approximately 200 described species. [ [http://www.lrz-muenchen.de/~schuessler/amphylo/amphylogeny.html Neue Seite 1 ] ] Members of the Glomeromycota form
arbuscular mycorrhizas with the roots or thalli (e.g. in bryophytes) of land plants. "Geosiphon pyriformis" forms an endocytobiotic association with " Nostoc" cyanobacteria [ [http://www.lrz-muenchen.de/~schuessler/geosiphon/geosiphon.html New Page 1 ] ] . AM formation has not yet been shown for all species. The majority of evidence shows that the Glomeromycota are obligate biotrophs, dependent on symbiosis with land plants ("Nostoc" in the case of "Geosiphon") for carbon and energy, but there is recent circumstantial evidence that some species may be able to lead an independent existence [cite journal
author=Hempel, S., Renker, C. & Buscot, F.
title=Differences in the species composition of arbuscular mycorrhizal fungi in spore, root and soil communities in a grassland ecosystem
doi=10.1111/j.1462-2920.2007.01309.x] . The
arbuscular mycorrhizal species are terrestrial and widely distributed in soils worldwide where they form symbioses with the roots of the majority of plant species. They can also be found in wetlands, including salt-marshes, and associated with epiphytic plants.
The Glomeromycota have generally coenocytic (occasionally sparsely septate)
myceliaand reproduce asexually through blastic development of the hyphal tip to produce spores (Glomerospores) with diameters of 80-500μm. In some, complex spores form within a terminal saccule.
Initial studies of the Glomeromycota were based on the morphology of soil-borne sporocarps (spore clusters) found in or near colonized plant roots. [cite journal
author=Tulasne, L.R., & C. Tulasne
title=Fungi nonnulli hipogaei, novi v. minus cogniti auct | journal=Giornale Botanico Italiano
pages=55–63] Distinguishing features such as wall morphologies, size, shape, color,
hyphal attachment and reaction to staining compounds allowed a phylogeny to be constructed.Wright, S.F. Management of Arbuscular Mycorrhizal Fungi. 2005. In Roots and Soil Management: Interactions between roots and the soil. Ed. Zobel, R.W., Wright, S.F. USA: American Society of Agronomy. Pp 183-197.] Superficial similarities led to the initial placement of genus "Glomus" in the unrelated family Endogonaceae. [cite journal
title=A revision of the Endogonaceae
journal=Proc. Am. Acad. Arts Sci.
pages=291–341] Following broader reviews that cleared up the sporocarp confusion, the Glomeromycota were first proposed in the genera "Acaulospora" and "Gigaspora" [cite journal
author=J.W. Gerdemann & J.M. Trappe
title=The Endogonaceae in the Pacific Northwest
pages=1–76] before being accorded their own order with the three families Glomaceae (now
Glomeraceae), Acaulosporaceae and Gigasporaceae. [cite journal
author=J.B. Morton & G.L. Benny
title=Revised classification of arbuscular mycorrhizal fungi (Zygomycetes): a new order, Glomales, two new suborders, Glomineae and Gigasporineae, and two new families, Acaulosporaceae and Gigasporaceae, with an emendation of Glomaceae
With the advent of molecular techniques this classification has undergone major revision. An analysis of small subunit (SSU)
rRNAsequences [cite journal
author = Schüßler, A. "et al."
title=Analysis of partial Glomales SSU rRNA gene sequences: implications for primer design and phylogeny
doi=10.1017/S0953756200003725] indicated that they share a common ancestor with the
Several species which produce glomoid spores (i.e. spores similar to "
Glomus") in fact belong to other deeply divergent lineages [cite journal|author=Redeker, D.|year= 2002|title= Molecular identification and phylogeny of arbuscular mycorrhizal fungi|journal= Plant and Soil|volume= 244|pages=67–73|doi= 10.1023/A:1020283832275] and were placed in the orders, Paraglomeralesand Archaeosporales. This new classification includes the Geosiphonaceae, which presently contains one fungus ("Geosiphon pyriformis") that forms endosymbiotic associations with the cyanobacterium "Nostoc punctiforme"cite journal|author=Schüßler, A.|year= 2002|title= Molecular phylogeny, taxonomy, and evolution of "Geosiphon pyriformis" and arbuscular mycorrhizal fungi|journal= Plant and Soil|volume= 224 |pages=75–83|doi= 10.1023/A:1020238728910] and produces spores typical to this phylum, in the Archaeosporales.
Work in this field is incomplete, and members of "Glomus" may be better suited to different genera [cite journal
author = Walker, C.
year = 1992
title = Systematics and taxonomy of the arbuscular mycorrhizal fungi (Glomales) - a possible way forward
journal = Agronomie
volume = 12
pages = 887–897
doi = 10.1051/agro:19921026] or families.cite journal
author=Simon, L., Bousquet, J., Levesque, C., Lalonde, M.
title= Origin and diversification of endomycorrhizal fungi and coincidence with vascular land plants
The biochemical and genetic characterization of the Glomeromycota has been hindered by their
biotrophicnature, which impedes laboratory culturing. This obstacle was eventually surpassed with the use of root cultures. The first mycorrhizal gene to be sequenced was the small-subunit ribosomal RNA(SSU rRNA). [cite journal
author=Simon, L. Lalonde, M. Bruns, T.D.
title= Specific Amplification of 18S Fungal Ribosomal Genes from Vesicular-Arbuscular Endomycorrhizal Fungi Colonizing Roots
journal= American Society of Microbiology
pages= 291–295] This gene is highly conserved and commonly used in phylogenetic studies so was isolated from
spores of each taxonomic group before amplification through the polymerase chain reaction(PCR). A molecular clockapproach, based on the substitution rates of SSU sequences, was used to estimate the time of divergence of the fungi. The molecular analysis found that they are between 462 and 353 Million years old. The data enforces the long-held theory that they were instrumental in the colonization of land by plants. [cite journal
author=D.W. Malloch, K.A. Pirozynski & P.H. Raven
title=Ecological and evolutionary significance of mycorrhizal symbiosis in vascular plants (a review)
Proc. Natl Acad. Sci. USA
* [http://tolweb.org/Glomeromycota/28715 Tree of Life Glomeromycota]
* [http://invam.caf.wvu.edu/fungi/taxonomy/glomales.htm Glomeromycota] at the International Culture Collection of VA Mycorrhizal Fungi (INVAM)
* [http://bugs.bio.usyd.edu.au/Mycology/Taxonomy/glomeromycota.shtml Glomeromycota] at the
University of Sydney Fungal Biologys|ite
* [http://amf-phylogeny.com 'AMF-phylogeny'] - 'Glomeromycota database' web-site at the University of Munich
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