Neil A. Brown PhD student
neil-a.brown@rothamsted.ac.uk

The infection biology and transcriptome of wheat pathogen Fusarium graminearum

Fusarium Ear Blight (FEB) is a destructive fungal disease of cereals including wheat and has the potential to devastate a farmer’s crop just weeks before harvest. Over the last 10 years the average incidence of the disease on wheat in the UK is up by 39%. This re-emergence is believed to be driven by changes to our climate and agronomic practices. Besides dramatically reducing a farmer’s yield, the harvested grains are also contaminated with a fungal toxin (mycotoxin) making them unsuitable and unsafe for human consumption, animal feed or malting purposes. Farmers in the UK pay the mill, where their grain is processed, to test for the presence of the mycotoxin and under EU safety guidelines approximately one infected ear per metre would be sufficient for their harvest to be rejected.

Attempts made to control the disease by traditional methods such as plant breeding and fungicide treatments have so far proven ineffective and may be costly. A definitive infection model recently published in Fungal Biology (Brown et al., 2010), of how the fungal pathogen spreads throughout the wheat ear has been developed, revealing why these control strategies have so far proven unsuccessful.

The macroscopic symptoms of Fusarium graminearum infection of wheat at 5 days post artificial inoculation. (A) An entire ear with a black dot marking each of the two inoculated spikelets. The two yellow horizontal lines superimposed on the inoculated PH-1 ear at 5 dpi indicate the extent of symptomless Fusarium colonisation identified by the microscopic analyses. (B) The inoculated spikelet and adjoining rachis node and rachis segment (overall height 12 mm). (C) and (D) Successive spikelets below the inoculated spikelet. The individually excised tissues of the inoculated spikelet, glume (E), lemma (F), palea (G).

Assessing the amount of fungal infection in the harvest prior to sending grain to the mill could save the farmer time and money. At present, disease assessments are done by scoring visible symptoms or measuring the quantity of fungal DNA in the grain. The infection model we recently developed demonstrates that the amount of visible symptoms represent only a small proportion of the total infected area in each ear. Consequently, the two approaches adopted by farmers could drastically underestimate disease level and possibly mycotoxin contamination.

Scanning electron micrographs: Three phases of the Fusarium graminearum infection of wheat ears. The F. graminearum initially spreads throughout the ear of wheat by passing between live plant cells. After a sustained period of interaction between live fungal and plant cells, the plant cell dies and is subsequently colonised by the fungus. Once inside the cell the fungus increases in abundance.

This fundamental research has proved a new bench mark from which future investigations can be developed and has opened up the possibility for the delivery of plant derived antifungal compounds designed to constrain the spread of infection or to subdue the production of the fungal toxin. Research into how this pathogen causes disease, the identification of fungicides targets and novel control strategies are ongoing at Rothamsted.

My project is supported by a BBSRC industrial CASE studentship awarded to Syngenta.

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Publications

Brown NA, Urban M, Antoniw J, and Hammond-Kosack K (2011) The Fusarium graminearum secretome. Fungal Genetics and Biology. In preparation for submission 2010.

Brown NA, Urban M, van de Meene A, and Hammond-Kosack K (2011) New tools to characterise Fusarium graminearum biomass accumulation and trichothecene mycotoxin gene expression in planta and in vitro. Molecular Plant Pathology. In preparation for submission 2011.

Brown NA, Urban M, van de Meene AML, and Hammond-Kosack KE (2010) The infection biology of Fusarium graminearum: Defining the pathways of spikelet to spikelet colonisation in wheat ears. Fungal Biology 114, 555-571.

Baldwin T, Urban M, Brown N, and Hammond-Kosack K (2010) A role for topoisomerase I in Fusarium graminearum and F. culmorum pathogenesis and sporulation. Molecular Plant-Microbe Interactions. 23, 556-577.

Kozlakidis Z, Brown NA, Jamal A, Phoon X, and Coutts R (2010) Incidence of endornaviruses in Phytophthora taxon douglasfir and Phytophthora ramorum. Virus Genes. 40, 130-134. (Joint 1st author)

Krasuss U, Hidalgo E, Bateman R, Adonijah V, Arroyo C, Garcia J, Crozier J, Brown NA, Hoopen M, and Holmes K (2010) Improving the formulation and timing of application of endophytic biocontrol and chemical agents against frosty pod rot (Moniliophthora rorei) in cocoa (Theobroma cacao). Biological Control 54, 230-240.

Wellner N, Mills C, Brownsey G, Wilson R, Brown N, Freeman J, Halford N, Shewry P, and Belton P (2005) Changes in protein secondary structure during gluten deformation studied by dynamic fourier transform infrared spectroscopy. Biomacromolecules 6, 255-261.

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Science Communication

BBC Radio Four Interview, Farmers Today, Research breakthroughs in farming.12/07/10

Farmers Weekly Interview, Cereals 2010, Spraying advice to control Fusarium. 10/07/10
Symptomless Fusarium infections should bring spraying forward. 15/07/10

Invited speaker on Applied Research, CropWorld 2010, The unseen threat to UK wheat production from Fusarium Ear Blight. 02/10/10

Brown et al., (2010) Rothamsted Research Assocation Newsletter, The unseen threat to UK wheat production of Fusarium Ear Blight.

Invited speaker, AAB Crop Protection in Southern Britain, The unseen threat of Fusarium Ear Blight and the implications for fungicide control. 23-24/02/2011

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Media Reports

	Cereals 2010: Spraying advice to control fusarium.
	Cereals 2010: The resurgence of Fusarium Ear Blight (by Neil A Brown and Kim Hammond-Kosack).
	Cereals 2010: Fusarium Ear Blight. Visible disease symptoms underestimate the extent of fungal infection (by Neil A Brown, M. Urban, A. M. L. Van de Meene and K. E. Hammond-Kosack).
	Cropworld 2010: Global Food Security at Cropworld 2010
	Rothamsted: The re-emergence of a destructive cereal disease poses a threat to UK wheat production
	Global Food Security:The re-emergence of a destructive cereal disease poses a threat to UK wheat production
	Farmers Weekly Interactive: Spraying advice to control fusarium
	Farmers Weekly Interactive: Symptomless-fusarium-infections-should-bring-spraying
	Promed Mail: Fusarium head blight, cereals - UK: re-emergence
	SeedQuest: Re-emergence of Fusarium head blight on cereals in the United Kingdom
	Farmers Guardian: Earlier spray may be needed for FEB control

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