Fusarium oxysporum

Fusarium oxysporum pronounce  (Schlecht as emended by Snyder and Hansen[1]), an ascomycete fungus, comprises all the species, varieties and forms recognized by Wollenweber and Reinking[2] within an infrageneric grouping called section Elegans. It is part of the family Nectriaceae.

Fusarium oxysporum
Scientific classification
Kingdom: Fungi
Division: Ascomycota
Class: Sordariomycetes
Order: Hypocreales
Family: Nectriaceae
Genus: Fusarium
Species:
F. oxysporum
Binomial name
Fusarium oxysporum
Schlecht. emend. Snyder & Hansen

Although their predominant role in native soils may be harmless or even beneficial plant endophytes or soil saprophytes, many strains within the F. oxysporum complex are pathogenic to plants, especially in agricultural settings.

Taxonomy

While the species, as defined by Snyder and Hansen, has been widely accepted for more than 50 years,[3][4] more recent work indicates this taxon is actually a genetically heterogeneous polytypic morphospecies[5][6] whose strains represent some of the most abundant and widespread microbes of the global soil microflora,[7] although this last statement has not been proven or supported by actual data.

Habitat

These diverse and adaptable fungi have been found in soils ranging from the Sonoran Desert, to tropical and temperate forest, grasslands and soils of the tundra.[8] F. oxysporum strains are ubiquitous soil inhabitants that have the ability to exist as saprophytes, and degrade lignin[9][10] and complex carbohydrates[11][12][1] associated with soil debris. They are pervasive plant endophytes that can colonize plant roots[13][14] and may even protect plants or form the basis of disease suppression.[15][16]

Because the hosts of a given forma specialis usually are closely related, many have assumed that members of a forma specialis are also closely related and descended from a common ancestor.[17] However, results from research conducted on Fusarium oxysporum f. sp. cubense forced scientists to question these assumptions. Researchers used anonymous, single-copy restriction fragment length polymorphsims (RFLPs) to identify 10 clonal lineages from a collection of F. oxysporum f.sp. cubense from across the world. These results showed that pathogens of banana causing Panama disease could be as closely related to other host's pathogens, such as melon or tomato, as they are to each other. Exceptional amounts of genetic diversity within F. oxysporum f.sp. cubense were deduced from the high level of chromosomal polymorphisms found among strains, random amplified polymorphic DNA fingerprints and from the number and geographic distribution of vegetative compatibility groups.[18]

Pathogen

Presented with the wide-ranging occurrence of F. oxysporum strains that are nonpathogenic, it is reasonable to conclude that certain pathogenic forms were descended from originally nonpathogenic ancestors. Given the association of these fungi with plant roots, a form that is able to grow beyond the cortex and into the xylem could exploit this ability and hopefully gain an advantage over fungi that are restricted to the cortex.

The progression of a fungus into vascular tissue may elicit an immediate host response, successfully restricting the invader; or an otherwise ineffective or delayed response, reducing the vital water-conducting capacity and induce wilting.[19] On the other hand, the plant might be able to tolerate limited growth of the fungus within xylem vessels, preceded by an endophytic association.[20] In this case, any further changes in the host or parasite could disturb the relationship, in a way that fungal activities or a host response would result in the generation of disease symptoms.

Pathogenic strains of F. oxysporum have been studied for more than 100 years. The host range of these fungi is broad and includes animals, ranging from arthropods[21] to humans,[22] as well as plants, including a range of both gymnosperms and angiosperms. While collectively, plant pathogenic F. oxysporum strains have a broad host range, individual isolates usually cause disease only in a narrow range of plant species. This observation has led to the idea of "special form" or forma specialis in F. oxysporum. Formae speciales have been defined as "…an informal rank in Classification… used for parasitic fungi characterized from a physiological standpoint (e.g. by the ability to cause disease in particular hosts) but scarcely or not at all from a morphological standpoint." Exhaustive host range studies have been conducted for relatively few formae speciales of F. oxysporum.[23] For more information on Fusarium oxysporum as a plant pathogen, see Fusarium wilt and Koa wilt.

Different strains of F. oxysporum have been used in the purpose of producing nanomaterials (especially Silver nanoparticles).

"Agent Green" in Colombia

In 2000, the government of Colombia proposed dispersing strains of Crivellia and Fusarium oxysporum, also known as Agent Green, as a biological weapon to forcibly eradicate coca and other illegal crops.[24] The weaponized strains were developed by the US government, who originally conditioned their approval of Plan Colombia on the use of this weapon, but ultimately withdrew the condition.[25] In February 2001, the EU Parliament also issued a declaration specifically against the use of these biological agents in warfare.[25]

Economic Importance

The fungus has the ability to dissolve gold, then excrete it onto the surface of the fungus, encrusting itself with gold. The fungus is currently being evaluated as a possible way to help detect hidden underground gold reserves.[26]

Formae speciales

See also

References
  1. Snyder WC, Hansen NH (1940). "The Species Concept in Fusarium". American Journal of Botany. 27 (2): 64–67. doi:10.1002/j.1537-2197.1940.tb14217.x. JSTOR 2436688.
  2. Wollenweber HW, Reinking OA (1935). Die Fusarien, ihre Beschreibung, Schadwirkung und Bekampfung [The fusariums, their description, harmful effects and control] (in German). Berlin: P. Parey. OCLC 1123368362.
  3. Booth C (1971). The genus Fusarium. Commonwealth Agricultural Bureaux [for the] Commonwealth Mycological Institute. ISBN 978-0-85198-046-1. OCLC 281402.
  4. Nelson PE, Toussoun TA, Marasas WF (1983). Fusarium species: an illustrated manual for identification. The Pennsylvania State University Press. ISBN 978-0-271-00349-8. OCLC 802515637.
  5. O'Donnell K, Cigelnik E (February 1997). "Two divergent intragenomic rDNA ITS2 types within a monophyletic lineage of the fungus Fusarium are nonorthologous". Molecular Phylogenetics and Evolution. 7 (1): 103–16. doi:10.1006/mpev.1996.0376. PMID 9007025.
  6. Waalwijk C, de Koning JR, Baayen RP, Gams W (1996). "Discordant Groupings of Fusarium spp. from Sections Elegans, Liseola and Dlaminia Based on Ribosomal ITS1 and ITS2 Sequences". Mycologia. 88 (3): 361–368. doi:10.1080/00275514.1996.12026663. JSTOR 3760877.
  7. Gordon TR, Martyn RD (1997). "The evolutionary biology of Fusarium oxysporum". Annual Review of Phytopathology. 35: 111–28. doi:10.1146/annurev.phyto.35.1.111. PMID 15012517. S2CID 33777569.
  8. Stoner MF (1981). "Ecology of Fusarium in noncultivated soils". In Nelson PE, Toussoun TA, Cook RJ (eds.). Fusarium: diseases, biology, and taxonomy. Pennsylvania State University Press. pp. 276–286. ISBN 978-0-271-00293-4.CS1 maint: date and year (link)
  9. Rodriguez A, Perestelo F, Carnicero A, Regalado V, Perez R, De la Fuente G, Falcon MA (November 1996). "Degradation of natural lignins and lignocellulosic substrates by soil-inhabiting fungi imperfecti". FEMS Microbiology Ecology. 21 (3): 213–219. doi:10.1111/j.1574-6941.1996.tb00348.x.
  10. Sutherland JB, Pometto III AL, Crawford DL (1 April 1983). "Lignocellulose degradation by Fusarium species". Canadian Journal of Botany. 61 (4): 1194–1198. doi:10.1139/b83-126.
  11. Christakopoulos P, Kekos D, Macris BJ, Claeyssens M, Bhat MK (February 1995). "Purification and mode of action of a low molecular mass endo-1,4-β-d-glucanase from Fusarium oxysporum". Journal of Biotechnology. 39 (1): 85–93. doi:10.1016/0168-1656(94)00147-5.
  12. Christakopoulos P, Nerinckx W, Kekos D, Macris B, Claeyssens M (November 1996). "Purification and characterization of two low molecular mass alkaline xylanases from Fusarium oxysporum F3". Journal of Biotechnology. 51 (2): 181–9. doi:10.1016/0168-1656(96)01619-7. PMID 8987884.
  13. Gordon TR, Okamoto D, Jacobson DJ (1989). "Colonization of muskmelon and nonsusceptible crops by Fusarium oxysporum f. sp. melonis and other species of Fusarium". Phytopathology. 79 (10): 1095–1100. doi:10.1094/Phyto-79-1095.
  14. Katan J (1971). "Symptomless carriers of the tomato Fusarium wilt pathogen". Phytopathology. 61 (10): 1213–1217. doi:10.1094/Phyto-61-1213.
  15. Larkin RP, Hopkins DL, Martin FN (1993). "Effect of successive watermelon plantings on Fusarium oxysporum and other microorganisms in soils suppressive and conducive to fusarium wilt of watermelon". Phytopathology. 83 (10): 1097–1105. doi:10.1094/Phyto-83-1097.
  16. Lemanceau P, Bakker PA, De Kogel WJ, Alabouvette C, Schippers B (January 1993). "Antagonistic Effect of Nonpathogenic Fusarium oxysporum Fo47 and Pseudobactin 358 upon Pathogenic Fusarium oxysporum f. sp. dianthi". Applied and Environmental Microbiology. 59 (1): 74–82. doi:10.1128/AEM.59.1.74-82.1993. PMC 202057. PMID 16348860.
  17. O'Donnell K, Kistler HC, Cigelnik E, Ploetz RC (March 1998). "Multiple evolutionary origins of the fungus causing Panama disease of banana: concordant evidence from nuclear and mitochondrial gene genealogies". Proceedings of the National Academy of Sciences of the United States of America. 95 (5): 2044–9. Bibcode:1998PNAS...95.2044O. doi:10.1073/pnas.95.5.2044. PMC 19243. PMID 9482835.
  18. Fourie G, Steenkamp ET, Gordon TR, Viljoen A (July 2009). "Evolutionary relationships among the Fusarium oxysporum f. sp. cubense vegetative compatibility groups". Applied and Environmental Microbiology. 75 (14): 4770–81. doi:10.1128/AEM.00370-09. PMC 2708428. PMID 19482953.
  19. Ploetz RC (June 2006). "Fusarium Wilt of Banana Is Caused by Several Pathogens Referred to as Fusarium oxysporum f. sp. cubense". Phytopathology. 96 (6): 653–6. doi:10.1094/PHYTO-96-0653. PMID 18943184.
  20. Appel DJ, Gordon TR (1994). "Local and regional variation in populations of Fusarium oxysporum from agricultural field soils". Phytopathology. 84 (8): 786–791. doi:10.1094/Phyto-84-786.
  21. Teetor-Barsch GH, Roberts DW (December 1983). "Entomogenous Fusarium species". Mycopathologia. 84 (1): 3–16. doi:10.1007/BF00436991. PMID 6369143. S2CID 21772636.
  22. Nelson PE, Dignani MC, Anaissie EJ (October 1994). "Taxonomy, biology, and clinical aspects of Fusarium species". Clinical Microbiology Reviews. 7 (4): 479–504. doi:10.1128/cmr.7.4.479. PMC 358338. PMID 7834602.
  23. Kistler HC (2001). "Evolution of host specificity in Fusarium oxysporum". In Nelson PE, Summerell BA (eds.). Fusarium: Paul E. Nelson Memorial Symposium. APS Press. pp. 70–82. ISBN 978-0-89054-268-2. OCLC 46786813.CS1 maint: date and year (link)
  24. "Grain — Sprouting Up: Battle Lines Drawn over Agent Green".
  25. "EU Parliament Rejects Agent Green for Colombia" (Press release). The Sunshine Project. 1 February 2001.
  26. Bohu T, Anand R, Noble R, Lintern M, Kaksonen AH, Mei Y, et al. (May 2019). "Evidence for fungi and gold redox interaction under Earth surface conditions". Nature Communications. 10 (1): 2290. Bibcode:2019NatCo..10.2290B. doi:10.1038/s41467-019-10006-5. PMC 6533363. PMID 31123249. Lay summary.
  27. Lawson RH (July 2011). "Detection, Diagnosis and Control of Lily Diseases". Acta Horticulturae (900): 313–324. doi:10.17660/ActaHortic.2011.900.40.

Bibliography
  • Hanks GR (1996). "Control of Fusarium oxysporum f.sp. narcissi, the cause of narcissus basal rot, with thiabendazole and other fungicides". Crop Protection. 15 (6 September): 549–558. doi:10.1016/0261-2194(96)00023-3.CS1 maint: ref=harv (link)
  • Hanks G, Carder J (2003). "Management of basal rot - the narcissus disease". Pesticide Outlook. 14 (6): 260. doi:10.1039/B314848N. S2CID 54515245.CS1 maint: ref=harv (link)
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