Metarhizium robertsii: Difference between revisions

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</ref> but they have now been assigned as new ''[[Metarhizium]]'' species,<ref name="J.F. Bisch., Rehner & Humber (2009)">{{cite journal
</ref> but they have now been assigned as new ''[[Metarhizium]]'' species in light of [[molecular taxonomy|new molecular evidence]];<ref name="J.F. Bisch., Rehner & Humber (2009)">{{cite journal
| title=A multilocus phylogeny of the ''Metarhizium anisopliae'' lineage
| title=A multilocus phylogeny of the ''Metarhizium anisopliae'' lineage
| journal=Mycologia
| journal=Mycologia
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| archive-url=https://web.archive.org/web/20200819092353/https://naldc-legacy.nal.usda.gov/naldc/download.xhtml?id=32523&content=PDF
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}}</ref> such as ''M. robertsii'', ''[[Metarhizium majus|M. majus]]'' and ''[[Metarhizium acridum|M. acridum]]'' (which was ''M. anisopliae'' var. ''acridum'' and included the isolates used for [[locust|locust control]]). ''Metarhizium taii'' was placed in ''M. anisopliae'' var. ''anisopliae'',<ref name="Huang et al. 2005">{{cite journal
}}</ref> one of these was ''M. robertsii''. Other examles were ''[[Metarhizium majus|M. majus]]'' and ''[[Metarhizium acridum|M. acridum]]'' (which was ''M. anisopliae'' var. ''acridum'' and included the isolates used for [[locust|locust control]]). ''Metarhizium taii'' was placed in ''M. anisopliae'' var. ''anisopliae'',<ref name="Huang et al. 2005">{{cite journal
| title=Molecular evidence for the taxonomic status of ''Metarhizium taii'' and its teleomorph, ''Cordyceps taii'' (Hypocreales, Clavicipitaceae)
| title=Molecular evidence for the taxonomic status of ''Metarhizium taii'' and its teleomorph, ''Cordyceps taii'' (Hypocreales, Clavicipitaceae)
| journal=Mycotaxon
| journal=Mycotaxon
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| title=Laboratory and field efficacy of entomopathogenic fungi for the management of the sweet potato weevil, ''Cylas formicarius'' (Coleoptera: Brentidae)
| title=Laboratory and field efficacy of entomopathogenic fungi for the management of the sweet potato weevil, ''Cylas formicarius'' (Coleoptera: Brentidae)
|author1=GVP Reddy |author2=Z Zhao |author3=RA Humber | doi=10.1016/j.jip.2014.07.009| doi-access=free | pmid=25111763
|author1=GVP Reddy |author2=Z Zhao |author3=RA Humber | doi=10.1016/j.jip.2014.07.009| doi-access=free | pmid=25111763
}}
}}</ref>

</ref> ''M. anisopliae'' has since been renamed ''M. robertsii'', [[patronymic taxon|renamed in honor]] of [[Donald W. Roberts]], who did his Ph.D. on this species, and has continued to work with it prolifically as a research professor ever since.<ref name="US-DOE-JGI">{{cite web | url=http://mycocosm.jgi.doe.gov/Metro1/Metro1.home.html | title=Home - Metarhizium robertsii ARSEF 23 | website=[[MycoCosm]], JGI, US DOE}}</ref>
==Important isolates==
''M. robertsii'' was named after Prof. [[Donald W. Roberts]], who’s PhD dissertation focused on [[destruxin]]s of the insect-pathogenic fungus then called "''[[Metarhizium anisopliae]]''"; Don continued to work with [[entomopathogenic fungi]], as a research professor, working especially with an isolate called ARSEF 23: which eventually became the type for this species.<ref name="US-DOE-JGI">{{cite web | url=http://mycocosm.jgi.doe.gov/Metro1/Metro1.home.html | title=Home - Metarhizium robertsii ARSEF 23 | website=[[MycoCosm]], JGI, US DOE}}</ref>


==Biology==
==Biology==
The disease caused by the fungus is sometimes called [[green muscardine disease]] because of the green colour of its [[spore]]s. When these mitotic (asexual) spores (called [[conidium|conidia]]) of the fungus come into contact with the body of an insect host, they germinate and the [[hypha]]e that emerge penetrate the [[cuticle]]. The fungus then develops inside the body, eventually killing the insect after a few days; this lethal effect is very likely aided by the production of insecticidal cyclic [[peptide]]s (destruxins). The cuticle of the cadaver often becomes red. If the ambient humidity is high enough, a white [[Mold (fungus)|mould]] then grows on the cadaver that soon turns green as spores are produced. Most insects living near the soil have evolved natural defenses against entomopathogenic fungi like ''M. robertsii''. This fungus is, therefore, locked in an evolutionary battle to overcome these defenses, which has led to a large number of [[Primary isolate|isolates]] (or [[Strain (biology)|strains]]) that are adapted to certain groups of insects.<ref name="Freimoser et al. 2003">{{cite journal
Insect diseases caused by fungi in this genus is sometimes called [[green muscardine disease]] because of the green colour of their [[spore]]s. When these mitotic (asexual) spores (called [[conidium|conidia]]) of the fungus come into contact with the body of an insect host, they germinate and the [[hypha]]e that emerge penetrate the [[cuticle]]. The fungus then develops inside the body, eventually killing the insect after a few days; this lethal effect is very likely aided by the production of insecticidal cyclic [[peptide]]s (destruxins). The cuticle of the cadaver often becomes red. If the ambient humidity is high enough, a white [[Mold (fungus)|mould]] then grows on the cadaver that soon turns green as spores are produced. Most insects living near the soil have evolved natural defenses against entomopathogenic fungi like ''M. robertsii''. This fungus is, therefore, locked in an evolutionary battle to overcome these defenses, which has led to a large number of [[Primary isolate|isolates]] (or [[Strain (biology)|strains]]) that are adapted to certain groups of insects.<ref name="Freimoser et al. 2003">{{cite journal
| author=Freimoser, F. M.
| author=Freimoser, F. M.
| author2=Screen, S.
| author2=Screen, S.

Latest revision as of 04:49, 28 April 2024

Metarhizium robertsii
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Fungi
Division: Ascomycota
Class: Sordariomycetes
Order: Hypocreales
Family: Clavicipitaceae
Genus: Metarhizium
Species:
M. robertsii
Binomial name
Metarhizium robertsii

Metarhizium robertsii is a fungus that grows naturally in soils throughout the world and causes disease in various insects by acting as a parasitoid. It is a mitosporic fungus with asexual reproduction, which was formerly classified in the form class Hyphomycetes of the phylum Deuteromycota (also often called fungi imperfecti).

Many isolates have long been recognised to be specific, and they were assigned variety status,[1] but they have now been assigned as new Metarhizium species in light of new molecular evidence;[2] one of these was M. robertsii. Other examles were M. majus and M. acridum (which was M. anisopliae var. acridum and included the isolates used for locust control). Metarhizium taii was placed in M. anisopliae var. anisopliae,[3] but has now been described as a synonym of M. guizhouense (see Metarhizium). The commercially important isolate M.a. 43 (or F52, Met52, etc.), which infects Coleoptera and other insect orders has now been assigned to Metarhizium brunneum.[4]

Important isolates[edit]

M. robertsii was named after Prof. Donald W. Roberts, who’s PhD dissertation focused on destruxins of the insect-pathogenic fungus then called "Metarhizium anisopliae"; Don continued to work with entomopathogenic fungi, as a research professor, working especially with an isolate called ARSEF 23: which eventually became the type for this species.[5]

Biology[edit]

Insect diseases caused by fungi in this genus is sometimes called green muscardine disease because of the green colour of their spores. When these mitotic (asexual) spores (called conidia) of the fungus come into contact with the body of an insect host, they germinate and the hyphae that emerge penetrate the cuticle. The fungus then develops inside the body, eventually killing the insect after a few days; this lethal effect is very likely aided by the production of insecticidal cyclic peptides (destruxins). The cuticle of the cadaver often becomes red. If the ambient humidity is high enough, a white mould then grows on the cadaver that soon turns green as spores are produced. Most insects living near the soil have evolved natural defenses against entomopathogenic fungi like M. robertsii. This fungus is, therefore, locked in an evolutionary battle to overcome these defenses, which has led to a large number of isolates (or strains) that are adapted to certain groups of insects.[6]

Economic importance[edit]

A simplified method of microencapsulation has been demonstrated to increase the shelf-life of M. robertsii spores commercialised for biological control of pest insects, potentially increasing its efficiency against red imported fire ants.[7]

M. Robertsii has been shown to break down very toxic mercury into less toxic forms of mercury. The fungus has been genetically engineered to improve its ability to perform this task.[8]

See also[edit]

References[edit]

  1. ^ Driver, F.; Milner, R.J. & Trueman, W.H.A. (2000). "A Taxonomic revision of Metarhizium based on sequence analysis of ribosomal DNA". Mycological Research. 104 (2): 135–151. doi:10.1017/S0953756299001756.
  2. ^ Bischoff J.F.; Rehner S.A. Humber R.A. (2009). "A multilocus phylogeny of the Metarhizium anisopliae lineage". Mycologia. 101 (4): 512–530. doi:10.3852/07-202. PMID 19623931. S2CID 28369561. Archived from the original on 2020-08-19. Retrieved 2018-12-29.
  3. ^ Huang B.; Li C.; Humber R.A.; Hodge K.T.; Fan M.; Li Z. (2005). "Molecular evidence for the taxonomic status of Metarhizium taii and its teleomorph, Cordyceps taii (Hypocreales, Clavicipitaceae)". Mycotaxon. 94: 137–147.
  4. ^ GVP Reddy; Z Zhao; RA Humber (2014). "Laboratory and field efficacy of entomopathogenic fungi for the management of the sweet potato weevil, Cylas formicarius (Coleoptera: Brentidae)". Journal of Invertebrate Pathology. 122: 10–15. doi:10.1016/j.jip.2014.07.009. PMID 25111763.
  5. ^ "Home - Metarhizium robertsii ARSEF 23". MycoCosm, JGI, US DOE.
  6. ^ Freimoser, F. M.; Screen, S.; Bagga, S.; Hu, G. & St. Leger, R.J. (2003). "EST analysis of two subspecies of M. anisopliae reveals a plethora of secreted proteins with potential activity in insect hosts". Microbiology. 149 (Pt 1): 239–247. doi:10.1099/mic.0.25761-0. PMID 12576597.
  7. ^ Qiu, Hua-Long; Fox, Eduardo G. P.; Qin, Chang-Sheng; Zhao, Dan-Yang; Yang, Hua; Xu, Jin-Zhu (2019-07-01). "Microcapsuled entomopathogenic fungus against fire ants, Solenopsis invicta" (PDF). Biological Control. 134: 141–149. doi:10.1016/j.biocontrol.2019.03.018. ISSN 1049-9644. S2CID 132021733.
  8. ^ Wu, Congcong; Tang, Dan; Dai, Jin; Tang, Xingyuan; Bao, Yuting; Ning, Jiali; Zhen, Qing; Song, Hui; St. Leger, Raymond J.; Fang, Weiguo (2022). "Bioremediation of mercury-polluted soil and water by the plant symbiotic fungus Metarhizium robertsii". Proceedings of the National Academy of Sciences. 119 (47). doi:10.1073/pnas.2214513119. PMC 9704736. PMID 36375055. S2CID 253522740.

External links[edit]