View source for Magnaporthe

{{Curated}}
{{Biorealm Genus}}

[[Image:manaporthe.jpg|thumb|250px|right|''Magnaporthe grisea'' '''A:''' Conidium with a drop of spore tip mucilage (STM) adhesive. '''B:''' Attachment of conidium by means fo STM. [http://arjournals.annualreviews.org/doi/pdf/10.1146/annurev.micro.50.1.491?cookieSet=1 Howard and Valent, "Breaking and Entering: Host Penetration by the Fungal Rice Blast Pathogen Magnaporthe grisea."]]]

==Classification==

===Higher order taxa===

Eukaryota; Fungi/Metazoa group; Fungi; Ascomycotoa; Pezizomycotina; Sordariomycetes; Sordariomycetes incertae sedis; Magnaporthaceae 

===Species===

''Magnaporthe grisea ''<br />''Magnaporthe oryzae''<br />''Magnaporthe rhizophila''

{|
| height="10" bgcolor="#FFDF95" |
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Undef&id=148303&lvl=3&lin=f&keep=1&srchmode=1&unlock Taxonomy] [http://www.nature.com/nature/journal/v434/n7036/abs/nature03449.html Genome]'''
|}

==Description and Significance==

''Magnaporthe'' is a genus within Ascomycota. This genus is most well-known for pathogenic species such as ''Magnaporteh grisea'', which causes rice blast disease.

==Genome Structure==

Dean et. al. published the draft sequence of the ''Magnaporthe grisea'' genome in 2005. The genome of ''M. grisea'' contains more genes than the genomes of its cousins, ''[[Neurospora|Neurospora crassa]]'' and ''[[Aspergillus|Aspergillus nidulans]]''. ''M. grisea'' has a high degree of genetic variablity.

==Cell Structure and Metabolism==

[[Image:lifecycle.jpg|thumb|200px|left|Diagram of life cycle. [http://www.nature.com/nature/journal/v434/n7036/abs/nature03449.html Dean et. al., "The genome sequence of the rice blast fungus ''Magnaporthe grisea''."]]]  [[Image:13550392.jpg|thumb|150px|right|Rice blast lesions on rice plant leaves. [http://ars.usda.gov/is/pr/2004/040812.htm Photo by R.K. Webster.]]]

''Magnaporthe ''are filamentous fungi. The species ''Maganporthe griseia'' is equipped with adhesives that are released from the tips of spores. This adhesive is called spore tip mucilage (STM) adhesive. It allows ''M griseia'' to bind to host organisms, beginning the infection process. The appressoria of ''M. griseia'' (described below) contains melanin. Appressoria also have thickened cell walls.

Like other members of [[Ascomycota]], ''Magnaporthe ''are heterotrophic organisms. They can obtain nutrients by decomposing organisms. Infectious species such as ''M. grisea'' and ''M. oryzae'' obtain nutrients from the hosts they infect.

''Magnaporthe ''are haploid organisms. However, they can reproduce both sexually and asexually. Because it is pathogenic, ''Magnaporthe'' ''grisea'' also has an infectious life cycle, which is asexual. The infectious form of ''M. griseia'' is called the conidium. After binding to its host, ''M. griseia'' developes a specialized dome-shaped infection cell called the appressorium. This cell generates turgor pressure which ruptures the host's leaf cuticle, allowing ''M. grisea '' to infect the leaf tissue. Once ''M. grisea'' colonizes its host, lesions form. These lesions are sites for fungus sporulation, allowing ''M. grisea'' to spread to more plants.





==Ecology==

The species ''Magnaporthe grisea'' causes rice blast disease. Upon infection, this fungus defeats or suppresses the plant's immune system, as well as affecting metabolism and cell signaling. Rice blast disease is so powerful that it kills enough rice to feed 60 million people annually, infecting plants all over the world. The Centers for Disease Control and Prevention consider this disease a major biological weapon. This disease adapts so well that it is able to defeat a rice cultivar, which is bred specifically to resist this fungus. In addition to rice, it attacks wheat, barley, millet, and turf grass. Severity of infection depends on what part of the plant becomes infected. If rice blast attacks young seedlings, a whole plant can die. However, if the disease attacks the stems, nodes, or panicle, the effects are much more severe. In these infections, the result is almost total loss of the rice grain. Rice blast disease also has the capacity to infect plant roots.

''Magnaporthe grisea'' is also considered a model organism for the study of fungal phytopathogenicity and host-parasite interactions.

==References==

[http://www.broad.mit.edu/annotation/fungi/magnaporthe/background.html Broad Institute. "''Magnaporthe Information.''" 24 June 2005. Accessed 21 July 2005. ]

[http://www.genomenewsnetwork.org/articles/09_02/blast_disease.shtml Dalke, Kate. "Fighting blast disease: Rice pathogen sequenced." ''Genome News Network''. 13 September 2002. Accessed 21 July 2005. ]

[http://www.nature.com/nature/journal/v434/n7036/abs/nature03449.html Dean, Ralph A. et. al. "The genome sequence of the rice blast fungus ''Magnaporthe grisea''." ''Nature''. 21 April 2005;434:980-986.]

[http://arjournals.annualreviews.org/doi/pdf/10.1146/annurev.micro.50.1.491?cookieSet=1 Howard, Richard J. and Barbara Valent. "Breaking and Entering: Host Penetration by the Fungal Rice Blast Pathogen ''Magnaporthe grisea''." Annu. Rev. Microbiol. 1996. 50:491–512.]

[http://www.pubmedcentral.gov/picrender.fcgi?artid=1170719&blobtype=pdf Kershaw, Michael J., Gavin Wakley, and Nicholas J. Talbot. "Complementation of the Mpg1 mutant phenotype in ''Magnaporthe grisea'' reveals functional relationships between fungal hydrophobins." The EMBO Journal Vol.17 No.14 pp.3838–3849, 1998. ]

[http://www.pubmedcentral.gov/picrender.fcgi?artid=168262&blobtype=pdf Kubo, Yasuyuki, Yoshitaka Takano, Noriko Edno, Nobuku Yasuda, Sohkichi Tajima, and Iwao Furusawa. "Cloning and Structural Analysis of the Melanin Biosynthesis Gene SCD1 Encoding Scytalone Dehydratase in Colletotrichum lagenarium." <span title="Applied and environmental microbiology.">Appl Environ Microbiol.</span> 1996 Dec;62(12):4340-4. ]

[http://ars.usda.gov/is/pr/2004/040812.htm Peabody, Erin. "Newly Exporter Rice Gene Could Help 'Blast' Killer Fungus." ''Agricultural Research Service''. 12 August 2005. ]