''Rhizophagus irregularis'' (previously known as ''Glomus intraradices'') is an

arbuscular mycorrhiza An arbuscular mycorrhiza (AM) (plural ''mycorrhizae'', a.k.a. ''endomycorrhiza'') is a type of mycorrhiza in which the symbiont fungus (''AM fungi'', or AMF) penetrates the cortical cells of the roots of a vascular plant forming arbuscules. ( ...

l fungus used as a

soil inoculant Microbial inoculants also known as soil inoculants or bioinoculants are agricultural amendments that use beneficial rhizosphericic or endophytic microbes to promote plant health. Many of the microbes involved form symbiotic relationships with the ...

agriculture Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people ...

and

horticulture Horticulture is the branch of agriculture that deals with the art, science, technology, and business of plant cultivation. It includes the cultivation of fruits, vegetables, nuts, seeds, herbs, sprouts, mushrooms, algae, flowers, seaweeds and no ...

. ''Rhizophagus irregularis'' is also commonly used in scientific studies of the effects of arbuscular mycorrhizal fungi on plant and soil improvement. Until 2001, the species was known and widely marketed as ''Glomus intraradices'', but molecular analysis of ribosomal DNA led to the reclassification of all arbuscular fungi from Zygomycota phylum to the Glomeromycota phylum.

Description

Spores

*Color - white, cream, yellow-brown Morton, J, & R Amarasinghe. ''Glomus intraradices''.''International Culture Collection of (Vesicular) Arbuscular Mycorrhizal Fungi''. 2006. West Virginia University. 17 November 2009. http://invam.caf.wvu.edu/index.html. *Shape - elliptical with irregularities *Size - generally between 40 - 140 μm

Hyphae

*Shape - Cylindrical or slightly flared *Size - Width: 11 - 18 μm

Identification

''Rhizophagus irregularis'' colonization peaks earlier than many of the other fungi in ''Rhizophagus''. There tends to be extensive hyphal networking and intense intraradical spores associated with older roots of host plants. At times the spores are densely clustered or patchily distributed, depending on the host species. When the spores are heavily clustered, mycorrhizologists and others will tend to mistake ''G. intraradices'' for ''G. fasciculatum''.

Reproduction

Rhizophagus irregularis (previously known as Glomus intraradices) has been found to colonise new plants by means of spores, hyphae or fragments of roots colonized by the fungus

Ecology and distribution

Distribution

''Rhizophagus irregularis'' can be found in almost all soils, especially those populated with common host plants and in forests and grasslands. This is a brief list of some common host plants. Most agricultural crops will benefit from ''Rhizophagus irregularis'' inoculation. Generally host plants must be vascular plants, but not always.Peterson, R, H Massicotte, L Melville (2004). ''Mycorrhizas: Anatomy and Cell Biology''. NRC Research Press, Ottawa: 7-8. *Onion - ''Allium cepa'' L. *Soapbush Wattle - ''Acacia holosericea'' *Flax - ''Linum usitatissimum'' L. *Cowpea - ''Vigna unguiculata'' *Tomato Plant - ''Lycopersicon esculentum'' *Albaida - ''Anthyllis cytisoides''

Conservation and status

''Rhizophagus irregularis'' is not of conservation concern; however, individual populations could be harmed by agricultural chemicals and tillage.

Relevance

In numerous scientific studies ''R. irregularis'' has been shown to increase phosphorus uptake in multiple plants as well as improve soil aggregation due to hyphae. Because of these qualities, ''R. irregularis'' is commonly found in mycorrhizal based fertilizers. In a recent study, ''R. irregularis'' was found to be the only

l fungi that was able to control nutrient uptake amounts by individual hyphae depending on differing phosphorus levels in the surrounding soil.

References

External links

*
JGI Mycorrhizal Genomics Initiative on Rhizophagus irregularis DAOM 181602 v1.0
{{Authority control Soil biology Glomerales Fungi described in 1982