Fusarium crown rot of wheat

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Crown Rot of Wheat
Causal agents: Fusarium pseudograminearum
Hosts: Wheat
EPPO code: GIBBCO
Fusarium pseudograminearum
Scientific classification
Kingdom: Fungi
Phylum: Ascomycota
Class: Sordariomycetes
Subclass: Hypocreomycetidae
Order: Hypocreales
Family: Nectriaceae
Genus: Fusarium
Species: F. pseudograminearum
Binomial name
Fusarium pseudograminearum

Crown Rot of Wheat is caused by the fungal pathogen Fusarium pseudograminearum . F. pseudograminearum is a member of the fungal phylum Ascomycota and is also known as Gibberella coronicola (teleomorph). It is a monoecious fungus, being that it does not require another host other than wheat to complete its life cycle. Although F. pseudograminearum can produce both anamorphic and teleomorphic states, the teleomorph is usually not present for Crown Rot of Wheat.[1] This Fusarium species has, until recently, been considered to be the same as the species known as F. graminearum (Head Blight of Wheat) due to many similar characteristics. One of the only differences between the two species would be that F. pseudograminearum lacks the presence of its sexual stage on the wheat host.[2]

An important characteristic in terms of infection that also distinguishes F. pseudgraminearum from F. graminearum, would be that F. pseudograminearum rarely infects the head of the wheat plant, only the crown, whereas F. graminearum can infect the entire wheat host.[3] Other than these differences, the signs and symptoms of both fungal pathogens are very similar, showing necrosis of the stem base and crown. F. pseudograminearum also produces mycotoxins once colonization of the wheat has been fully established, which are responsible for the majority of the symptoms produced.[4] Crown Rot of Wheat is an important plant disease that needs to be well managed due to its detrimental effects that it can have on entire fields of wheat. The infection of F. pseudograminearum can develop during stressful, water deficits in fields and can spread quickly to other wheat plants, whose symptoms will ultimately lead to plant death.[5]

Hosts and symptoms[edit]

F. pseudograminearum has a limited host range, only infecting species of wheat and barley. F. pseudograminearum can infect seedlings, but can also infect the crowns of mature wheat hosts. Crown Rot of Wheat produces asexual structures called conidiospores, which are produced in sporodochium structures inside the stem of the infected host. As the conidiospores germinate and invade the xylem and pith of the stem, both the stem and crown develop a red-brown or white discoloration.[6] The primary infection of the host’s xylem is thought to occur at the crown or lower sheath of the stem from stubble containing a spore and mycelial inoculum.[7] The infection of the xylem leaves the tissue water-soaked and with a pink or salmon color. As the infection proliferates the crown then becomes punky and is ultimately dysfunctional.[8]

Due to the vast infection throughout the host, the plants growth is stunted and will show incomplete grain fill. As well as infecting the xylem and pith of the host, F. pseudograminearum produces mycotoxins once it has fully been established. Mycotoxins are toxins produced by fungi that are harmful to animals and human if consumed. F. pseudograminearum produces the trichothecene mycotoxin DON, which spreads throughout the plant stem and builds up in the tissue. The production of DON can produce the formation of whiteheads, which are heads of grain that died prematurely. It is known that F. pseudograminearum doesn’t infect the heads of the wheat, but the formation of the “whiteheads” is a secondary symptom of the buildup of the mycotoxin DON.[9] The transport dysfunction occurring in the xylem and the buildup of mycotoxin DON will ultimately lead to death of the infected wheat plants.[10]

Disease cycle[edit]

The disease cycle of F. pseudograminearum includes both sexual and asexual stages, however the sexual stage has been observed to not play an important role in the establishment of the disease.[11] Overwintering on crop residue, seeds, or in the soil is easily accomplished for this Fusarium species due to the formation of survival structures called chlamydospores. As spring arrives the chlamydospores are signaled to germinate producing asexual structures called conidia.[12] As mentioned previously, the formation of sexual structures are rare in the field, but the pathogen’s teleomorph would produce structures called perithecia. As the perithecia form they would produce asci that contain ascospores inside. The perithecia forcibly discharge the ascospores and then those airborne spores are disseminated either by wind, rain, or animal. These sexual spores then land on a mature wheat host and would start to colonize the stem and area around the crown as summer proliferates.[13] However, the asexual stage of F. pseudograminearum is a much simpler cycle that produces the most damage to the wheat.

Conidia, produced from the chlamydospores in soil or spread by wind, can infect wheat through natural openings and colonize the xylem and pith of the host.[14] Formation of asexual structures called sporodochium can produce even more conidia, which act as a repeating infection stage. Soon the wheat plant will have multiple infection sites, most of which are near the crown.[15] As harvest season approaches at the end of the summer the dry warm environment has allowed F. pseudograminearum to colonize the plant and start producing harmful mycotoxins that produce secondary symptoms in the grains of the wheat. Mycotoxin DON is harmful to animal and humans that consume the wheat, which makes the crop inedible and thus a costly problem (Miedaner et al. 2008).

Environment[edit]

Crown Rot of wheat caused by Fusarium is a widespread disease. It was previously believed that Crown Rot is restricted in its geographical distribution. In the United States, the disease is most prevalent in the driest and warmest regions of the Pacific Northwest.[16] However, recent investigations have suggested that the disease is found is most cereal producing regions of the world.[17]

Local environmental conditions play a large role in the prevalence of F. pseudograminearum. This is particularly evident during late season when the crops are maturing.[18] While both rainfall and temperature are important, studies have shown that rainfall plays a much larger role in the prevalence and severity of Crown Rot; although a weak temperature-disease correlation does exist.[19] In the field survey of wheat crops in Australia, the maximum summer temperature in areas where F. pseudograminearum was found to be as high as 31°C.[20] Under drought conditions, where warm and dry weather predominates, Crown Rot symptoms are intensified. This is largely due to the pathogen's ability to survive and thrive under these conditions. Laboratory studies suggest that F. pseudograminearum grows best under dry (<-1MPa) conditions.[21] They further showed that while the pathogen grew fairly well in temperatures ranging from 5°C to 30°C, it does not grow well at 5°C or 35º.[22]

Management[edit]

The most common management practice for controlling Fusarium crown rot on wheat is to use resistant varieties. While no fully resistant variety exists, resistance in the form of tolerance to the disease can be used. A few of the resistant wheat varieties include: 2-49, Sunco, Kukri, Brundage, Gene, Weatherford, Madson, Temple, and Tubbs.[23][24] Tolerance still allows the host to become infected by the pathogen, but it provides the host with the ability to withstand the infection and produce an acceptable yield.[25]

Agronomic practices can be used to reduce the severity of Fusarium crown rot on wheat, but they cannot eliminate the disease. Practices which can help reduce the risk of disease are: not rotating wheat with oats, tilling fields after harvest to improve water infiltration, establishing a dust and stubble mulch in the spring, applying the correct amount of nitrogen to fields, and plant wheat at an intermediate planting date which balances the larger plants and greater stress of early planting with the lower yields of later planting.[26] These practices work to reduce disease by creating an unfavorable environment for the pathogen or by making the host less susceptible. Since these practices don’t necessarily line up with preferred agronomic and economic considerations, the use of resistant or tolerant varieties is becoming the accepted management practice.[27]

Importance[edit]

Fusarium Crown Rot is one of the most important ailments affecting wheat. Because of wheat’s central role in the global diet, Crown Rot represents a major economic concern. Not only is Crown Rot severe, it is also widespread.[28] Across the United States, average losses in winter wheat resulting from Crown Rot have been estimated to be as high as 9.5% through large areas of the Pacific northwest.[29] Similar losses are seen in other western states in the United States.[30]

Beyond North America, Crown Rot is a particularly concerning disease in Australia. In the past three decades, Crown Rot has become the disease of greatest relative importance in the northern grain producing regions of Australia.[31] Overall, it is only second to Septoria blotch in terms of its economic impact to wheat.[32] Experts believe that the recent surge in Crown Rot prevalence in Australia is most likely resulting from cereals being growing in closer rotations and stubble retention practices becoming more prevalent.[33] Furthermore, in seasons where environmental conditions permit, Crown Rot can decrease wheat yield by up to 100% in Australia and up to 65% in North America.[34]

Aside from the disease-induced crop loss, Crown Rot is also significant due to the toxicity of infected wheat. As noted above, DON is produced by F. pseudograminearum during disease development.[35] DON has been showed to be toxic to both humans as well as animals after they inject the infected crop.[36] In some European nations, the government has put out regulatory guidelines suggesting that DON's total daily intake should not exceed 1μg/kg.[37] Therefore, the combination of yield loss and diseased crop toxicity makes Crown Rot an extremely important disease for global food supply.

External links[edit]

References[edit]

  1. ^ Backhouse, D; Abubaker, AA; Burgess, LW; Dennis, JI; Hollaway; Wildermuth, GB; Wallwork, H; Henry, FJ, (2004) Survey of Fusarium Species Associated with Crown Rot of Wheat and Barley in Eastern Australia, Australian Plant Pathology Society, Vol 33, pp255–261.
  2. ^ Stephens, AE; Gardiner, DM; White, RG; Munn, AL; Manners, JM, (2008) Phases of Infection and Gene Expression of Fusarium graminearum During Crown Rot Disease of Wheat, Molecular Plant-Microbe Interactions, Vol 21, No. 12, pp1571–1581. 10. Wallwork, H; Butt, M; Cheong, JPE; Williams, KJ,(2004) Resistance to Crown Rot in Wheat Identified Through an Improved Method for Screening Adult Plants, Australian Plant Pathology Society, Vol 33, pp1–7
  3. ^ Agnieszka M. Mudge, Ruth Dill-Macky, et al,(2006) A role for the mycotoxin deoxynivalenol in stem colonisation during crown rot disease of wheat caused by Fusarium graminearum and Fusarium pseudograminearum, Physiological and Molecular Plant Pathology, Volume 69, Issues 1–3, July–September, Pages 73-85, ISSN 0885-5765, 10.1016/j.pmpp.2007.01.003. (http://www.sciencedirect.com/science/article/pii/S0885576507000173)
  4. ^ Agnieszka M. Mudge, Ruth Dill-Macky, et al,(2006) A role for the mycotoxin deoxynivalenol in stem colonisation during crown rot disease of wheat caused by Fusarium graminearum and Fusarium pseudograminearum, Physiological and Molecular Plant Pathology, Volume 69, Issues 1–3, July–September, Pages 73-85, ISSN 0885-5765, 10.1016/j.pmpp.2007.01.003. (http://www.sciencedirect.com/science/article/pii/S0885576507000173)
  5. ^ Agnieszka M. Mudge, Ruth Dill-Macky, et al,(2006) A role for the mycotoxin deoxynivalenol in stem colonisation during crown rot disease of wheat caused by Fusarium graminearum and Fusarium pseudograminearum, Physiological and Molecular Plant Pathology, Volume 69, Issues 1–3, July–September, Pages 73-85, ISSN 0885-5765, 10.1016/j.pmpp.2007.01.003. (http://www.sciencedirect.com/science/article/pii/S0885576507000173)
  6. ^ Desmond, Olivia,Edgar, Cameraon et al,(2006) Methyl jasmonate induced gene expression in wheat delays symptom development by the crown rot pathogen Fusarium pseudograminearum, Physiological and Molecular Plant Pathology, Volume 67, Issues 3–5, September 2005–October 2006, Pages 171-179, ISSN 0885-5765, 10.1016/j.pmpp.2005.12.007. (http://www.sciencedirect.com/science/article/pii/S0885576506000026)
  7. ^ Desmond, Olivia,Edgar, Cameraon et al,(2006) Methyl jasmonate induced gene expression in wheat delays symptom development by the crown rot pathogen Fusarium pseudograminearum, Physiological and Molecular Plant Pathology, Volume 67, Issues 3–5, September 2005–October 2006, Pages 171-179, ISSN 0885-5765, 10.1016/j.pmpp.2005.12.007. (http://www.sciencedirect.com/science/article/pii/S0885576506000026)
  8. ^ Chakraborty, S; Liu, CJ; Mitter, V; Scott, JB; Akinsanmi, OA; Ali, S; Dill-Macky, R; Nicol, J; Backhouse, D; Simpfendorfer, S, (2006) Pathogen Population Structure and Epidemiology are Keys to Wheat Crown Rot and Fusarium Head Blight Management, Australian Plant Pathology Society, Vot 35, pp643–655
  9. ^ Agnieszka M. Mudge, Ruth Dill-Macky, et al,(2006) A role for the mycotoxin deoxynivalenol in stem colonisation during crown rot disease of wheat caused by Fusarium graminearum and Fusarium pseudograminearum, Physiological and Molecular Plant Pathology, Volume 69, Issues 1–3, July–September, Pages 73-85, ISSN 0885-5765, 10.1016/j.pmpp.2007.01.003. (http://www.sciencedirect.com/science/article/pii/S0885576507000173)
  10. ^ Nyvall, RF. Field Crop Diseases. 3rd ed. Ames, Iowa: Iowa State University Press, 1999
  11. ^ Chakraborty, S; Liu, CJ; Mitter, V; Scott, JB; Akinsanmi, OA; Ali, S; Dill-Macky, R; Nicol, J; Backhouse, D; Simpfendorfer, S, (2006) Pathogen Population Structure and Epidemiology are Keys to Wheat Crown Rot and Fusarium Head Blight Management, Australian Plant Pathology Society, Vot 35, pp643–655
  12. ^ Chakraborty, S; Liu, CJ; Mitter, V; Scott, JB; Akinsanmi, OA; Ali, S; Dill-Macky, R; Nicol, J; Backhouse, D; Simpfendorfer, S, (2006) Pathogen Population Structure and Epidemiology are Keys to Wheat Crown Rot and Fusarium Head Blight Management, Australian Plant Pathology Society, Vot 35, pp643–655.
  13. ^ Chakraborty, S; Liu, CJ; Mitter, V; Scott, JB; Akinsanmi, OA; Ali, S; Dill-Macky, R; Nicol, J; Backhouse, D; Simpfendorfer, S, (2006) Pathogen Population Structure and Epidemiology are Keys to Wheat Crown Rot and Fusarium Head Blight Management, Australian Plant Pathology Society, Vot 35, pp643–655
  14. ^ Stephens, AE; Gardiner, DM; White, RG; Munn, AL; Manners, JM, (2008) Phases of Infection and Gene Expression of Fusarium graminearum During Crown Rot Disease of Wheat, Molecular Plant-Microbe Interactions, Vol 21, No. 12, pp1571–1581. 10. Wallwork, H; Butt, M; Cheong, JPE; Williams, KJ,(2004) Resistance to Crown Rot in Wheat Identified Through an Improved Method for Screening Adult Plants, Australian Plant Pathology Society, Vol 33, pp1–7
  15. ^ Chakraborty, S; Liu, CJ; Mitter, V; Scott, JB; Akinsanmi, OA; Ali, S; Dill-Macky, R; Nicol, J; Backhouse, D; Simpfendorfer, S, (2006) Pathogen Population Structure and Epidemiology are Keys to Wheat Crown Rot and Fusarium Head Blight Management, Australian Plant Pathology Society, Vot 35, pp643–655
  16. ^ Backhouse, D., Burgess, L., (2002) Climate analysis of the distribution of Fusarium graminearum, F. pseudograminerarum, and F. culmorum on cereals in Australia, Australiaisan Plant Pathology, Vol. 31, P.321-327
  17. ^ Chakraborty, S; Liu, CJ; Mitter, V; Scott, JB; Akinsanmi, OA; Ali, S; Dill-Macky, R; Nicol, J; Backhouse, D; Simpfendorfer, S, (2006) Pathogen Population Structure and Epidemiology are Keys to Wheat Crown Rot and Fusarium Head Blight Management, Australian Plant Pathology Society, Vot 35, pp643–655
  18. ^ Chakraborty, S; Liu, CJ; Mitter, V; Scott, JB; Akinsanmi, OA; Ali, S; Dill-Macky, R; Nicol, J; Backhouse, D; Simpfendorfer, S, (2006) Pathogen Population Structure and Epidemiology are Keys to Wheat Crown Rot and Fusarium Head Blight Management, Australian Plant Pathology Society, Vot 35, pp643–655
  19. ^ Backhouse, D; Abubaker, AA; Burgess, LW; Dennis, JI; Hollaway; Wildermuth, GB; Wallwork, H; Henry, FJ, (2004) Survey of Fusarium Species Associated with Crown Rot of Wheat and Barley in Eastern Australia, Australian Plant Pathology Society, Vol 33, pp255–261
  20. ^ Backhouse, D., Burgess, L., (2002) Climate analysis of the distribution of Fusarium graminearum, F. pseudograminerarum, and F. culmorum on cereals in Australia, Australiaisan Plant Pathology, Vol. 31, P.321-327
  21. ^ Singh, D., Backhouse, D., Kristiansen, P., (2009) Interaction of temperature and water potential in displacement of Fusarium pseudograminearum from cereal residues by fungal antagonists, Biological Control, Vol. 48, P.188-195
  22. ^ Singh, D., Backhouse, D., Kristiansen, P., (2009) Interaction of temperature and water potential in displacement of Fusarium pseudograminearum from cereal residues by fungal antagonists, Biological Control, Vol. 48, P.188-195
  23. ^ Chakraborty, S; Liu, CJ; Mitter, V; Scott, JB; Akinsanmi, OA; Ali, S; Dill-Macky, R; Nicol, J; Backhouse, D; Simpfendorfer, S, (2006) Pathogen Population Structure and Epidemiology are Keys toWheat Crown Rot and Fusarium Head Blight Management, Australian Plant Pathology Society, Vot 35, pp643–655
  24. ^ Smiley et al. GENETIC TOLERANCE TO FUSARIUM CROWN ROT OF WHEAT. http://extension.oregonstate.edu/catalog/html/sr/sr1047-e/40.htm
  25. ^ Smiley et al. GENETIC TOLERANCE TO FUSARIUM CROWN ROT OF WHEAT. http://extension.oregonstate.edu/catalog/html/sr/sr1047-e/40.htm
  26. ^ Nyvall, RF. Field Crop Diseases. 3rd ed. Ames, Iowa: Iowa State University Press, 1999,
  27. ^ Smiley et al. GENETIC TOLERANCE TO FUSARIUM CROWN ROT OF WHEAT. http://extension.oregonstate.edu/catalog/html/sr/sr1047-e/40.htm
  28. ^ Backhouse, D; Abubaker, AA; Burgess, LW; Dennis, JI; Hollaway; Wildermuth, GB; Wallwork, H; Henry, FJ, (2004) Survey of Fusarium Species Associated with Crown Rot of Wheat and Barley in Eastern Australia, Australian Plant Pathology Society, Vol 33, pp255–261
  29. ^ Hogg, AC; Johnston, RH; Klouser, L; Kephart, KD; Dyer, AT,(2010) Monitoring Fusarium Crown Rot Populations in Spring Wheat Residues Using Quantitative Real-Time Polymerase Chain Reaction, Phytopathology, Vol 100, No. 1, pp49–57
  30. ^ Hogg, AC; Johnston, RH; Klouser, L; Kephart, KD; Dyer, AT,(2010) Monitoring Fusarium Crown Rot Populations in Spring Wheat Residues Using Quantitative Real-Time Polymerase Chain Reaction, Phytopathology, Vol 100, No. 1, pp49–57
  31. ^ Backhouse, D; Abubaker, AA; Burgess, LW; Dennis, JI; Hollaway; Wildermuth, GB; Wallwork, H; Henry, FJ, (2004) Survey of Fusarium Species Associated with Crown Rot of Wheat and Barley in Eastern Australia, Australian Plant Pathology Society, Vol 33, pp255–261
  32. ^ Chakraborty, S; Liu, CJ; Mitter, V; Scott, JB; Akinsanmi, OA; Ali, S; Dill-Macky, R; Nicol, J; Backhouse, D; Simpfendorfer, S, (2006) Pathogen Population Structure and Epidemiology are Keys to Wheat Crown Rot and Fusarium Head Blight Management, Australian Plant Pathology Society, Vot 35, pp643–655
  33. ^ Wallwork, H., Butt, M., Cheong, J., et al, (2004) Resistance to crown rot in wheat identified through an improved method for screening adult plants, Australasian Plant Path., Vol. 33, P.1-7
  34. ^ . Stephens, AE; Gardiner, DM; White, RG; Munn, AL; Manners, JM, (2008) Phases of Infection and Gene Expression of Fusarium graminearum During Crown Rot Disease of Wheat, Molecular Plant-Microbe Interactions, Vol 21, No. 12, pp1571–1581. 10. Wallwork, H; Butt, M; Cheong, JPE; Williams, KJ,(2004) Resistance to Crown Rot in Wheat Identified Through an Improved Method for Screening Adult Plants, Australian Plant Pathology Society, Vol 33, pp1–7
  35. ^ Desmond, O., Manner, J., Stephens, D., et al, (2008) The Fusarium mycothoxin deoxynivalenol elicits hydrogen peroxide production, programmed cell death and defense in wheat, Mol. Plant Path., Vol. 9, P.435-445
  36. ^ Desmond, O., Manner, J., Stephens, D., et al, (2008) The Fusarium mycothoxin deoxynivalenol elicits hydrogen peroxide production, programmed cell death and defense in wheat, Mol. Plant Path., Vol. 9, P.435-445
  37. ^ Larsen, J., Hunt, J., Perrin, I., et al, (2004) Workshop on trichothecenes with a focus on DON: summary report, Toxicology Letters, Vol. 153, P.1-22