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Fusarium Head Blight disease develop...

Willyerd, Katelyn Tilley.

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Fusarium Head Blight disease development and mycotoxin accumulation in wheat.

紀錄類型:	書目-語言資料,印刷品 : Monograph/item
正題名/作者:	Fusarium Head Blight disease development and mycotoxin accumulation in wheat./
作者:	Willyerd, Katelyn Tilley.
面頁冊數:	137 p.
附註:	Source: Dissertation Abstracts International, Volume: 70-11, Section: B, page: 6629.
Contained By:	Dissertation Abstracts International70-11B.
標題:	Agriculture, Horticulture. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3381036
ISBN:	9781109463200

Fusarium Head Blight disease development and mycotoxin accumulation in wheat.
Willyerd, Katelyn Tilley.

Fusarium Head Blight disease development and mycotoxin accumulation in wheat. - 137 p.

Source: Dissertation Abstracts International, Volume: 70-11, Section: B, page: 6629.

Thesis (Ph.D.)--The Pennsylvania State University, 2009.

Fusarium graminearum, causal agent of Fusarium Head Blight (FHB) of wheat, causes yield losses and contaminates grain with mycotoxins, most commonly deoxynivalenol (DON). The purpose of this dissertation was to characterize FHB disease development and mycotoxin accumulation during the grain development stages in wheat.

ISBN: 9781109463200Subjects--Topical Terms:

1017832
Agriculture, Horticulture.

Fusarium Head Blight disease development and mycotoxin accumulation in wheat.
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100 1 $a Willyerd, Katelyn Tilley. $3 1676777
245 1 0 $a Fusarium Head Blight disease development and mycotoxin accumulation in wheat.
300 $a 137 p.
500 $a Source: Dissertation Abstracts International, Volume: 70-11, Section: B, page: 6629.
500 $a Adviser: Gretchen Kuldau.
502 $a Thesis (Ph.D.)--The Pennsylvania State University, 2009.
520 $a Fusarium graminearum, causal agent of Fusarium Head Blight (FHB) of wheat, causes yield losses and contaminates grain with mycotoxins, most commonly deoxynivalenol (DON). The purpose of this dissertation was to characterize FHB disease development and mycotoxin accumulation during the grain development stages in wheat.
520 $a A two-year field experiment was designed to study the effects of infection-timing and cultivar on disease severity, kernel damage and accumulation of DON. Three winter wheat cultivars, with different degrees of susceptibility to FHB, were planted in a split-plot design. Misting treatments were designed to facilitate infections during anthesis and/or late-milk stages. All plots were inoculated with F. graminearum macroconidia prior to each misting treatment to ensure the presence of the pathogen. Disease severity of each subplot was assessed during the dough stages, while Fusarium-damaged kernels (FDK) and DON accumulation were measured post-harvest. Misting treatment, cultivar and their interactions were significant factors for severity, FDK and DON. This study confirmed that infections during both anthesis and grain-fill contributed to symptoms and DON levels. Infections during grain-fill alone contributed to DON accumulation (> 2ppm) and had little effect on symptoms. Response to infection-timing was found to be cultivar-specific. Infection-timing and host genotype interactions play significant roles in disease development and mycotoxin contamination of wheat.
520 $a The second objective of this work was to develop a method to simultaneously detect DON and fungal biomass in wheat heads, as the relationship between toxin production and fungal growth is not fully understood. By analyzing single wheat florets from infected wheat heads, infection and toxin accumulation patterns could be studied. Deoxynivalenol was extracted from FHB-affected single florets with acetonitrile-water. Ergosterol, a fungal-specific sterol found in the cell membrane, was used as a biomarker for fungal biomass. Ergosterol was removed from the same wheat florets through saponification and extraction with hexane. Toxin and ergosterol extracts were combined and analyzed via gas chromatography with electron capture detection (GC-ECD). This method was also designed to detect deoxynivalenol-3-glucoside (DON-gluc), a conjugated mycotoxin, which forms in planta. Retention times were confirmed with analytical standards and standard curves were created to estimate concentrations of these in floret samples. The limits of quantification were 0.005, 0.050 and 0.100ng/il for DON, ergosterol and DON-gluc, respectively. The extraction protocols and GC-ECD method are tools with the potential to study trichothecene accumulation and fungal colonization of many important agricultural commodities.
520 $a The final goal was to use the GC-ECD method to study the effects of temperature and cultivar on fungal biomass and DON accumulation in wheat heads. Two spring wheat cultivars were used in this study: 'Alsen' (moderately resistant) and 'Wheaton' (susceptible). A central spikelet was inoculated during mid-anthesis. Plants were incubated at 15 or 22°C. Spikelets, each containing two florets, were harvested at 2, 4, 6, 8 and 10 days post-inoculation (dpi). One floret was placed on Nash agar to determine F. graminearum incidence. The remaining floret was reserved for GC-ECD analysis. Colonization beyond the inoculated spikelet and DON translocation to florets not colonized by Fusarium were observed by 2dpi. During the early stages of infection, wheat heads in the 22°C treatment experienced greater Fusarium incidence than those incubated at 15°C. The interactive effect of cultivar and temperature was significant for both DON and ergosterol accumulation in wheat florets. The resistant cultivar 'Alsen' experienced the highest levels of DON accumulation when incubated at 15°C, but the least amount of ergosterol. This suggests that stressful conditions, such as resistant host and cool temperatures, may limit Fusarium growth and stimulate DON production during early stages of grain development. Both cultivars produced DON-gluc by 6dpi. 'Wheaton' produced greater levels of DON-gluc than 'Alsen', especially by 10dpi. This may, in part, explain the lack of DON increase between 8 and 10dpi. Future work may include extending harvest dates to characterize DON, DON-gluc and ergosterol production and accumulation throughout grain development until harvest. The findings of this dissertation contribute to the greater understanding of FHB epidemiology and mycotoxin accumulation in wheat. (Abstract shortened by UMI.)
590 $a School code: 0176.
650 4 $a Agriculture, Horticulture. $3 1017832
650 4 $a Agriculture, Plant Pathology. $3 1028950
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790 1 0 $a Kuldau, Gretchen, $e advisor
790 $a 0176
791 $a Ph.D.
792 $a 2009
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