Pathogenic specialization in Fusarium graminearum

1971 ◽  
Vol 22 (4) ◽  
pp. 553 ◽  
Author(s):  
GS Purss
Keyword(s):  
United States ◽  
Fusarium Graminearum ◽  
The United States ◽  
Crown Rot ◽  
Foot Rot ◽  
Significant Extent ◽  
Head Blight ◽  
Stalk Rot ◽  
Specialized Form

Isolates of Fusarium graminearum from crown rot of wheat, stalk rot of maize (both in Australia and in the United States), and head blight of wheat are all shown to be capable of causing head blight of wheat to a significant level. Stalk rot of maize is shown to be caused by isolates of F. graminearum from stalk rot of maize, crown rot of wheat, and head blight of wheat. Isolates of F. culmorum from foot rot of wheat and barley are also capable of causing stalk rot of maize. Typical crown rot of wheat is shown to be caused to a significant extent only by the isolates from this disease syndrome. The conclusion is drawn that a specialized form of F. graminearurn is responsible for crown rot in wheat.

scholarly journals Resistance in Winter Wheat Lines to Initial Infection and Spread Within Spikes by Deoxynivalenol and Nivalenol Chemotypes of Fusarium graminearum

Plant Disease ◽  
2011 ◽  
Vol 95 (1) ◽  
pp. 31-37 ◽  
Author(s):  
Peter Horevaj ◽  
Liane R. Gale ◽  
Eugene A. Milus
Keyword(s):  
United States ◽  
Winter Wheat ◽  
Fusarium Graminearum ◽  
The United States ◽  
Blight Resistance ◽  
Head Blight ◽  
Initial Infection ◽  
Additional Information ◽  
Progress Curve ◽  
Wheat Lines

Head blight of wheat in the United States is caused primarily by the deoxynivalenol (DON)-producing chemotype of Fusarium graminearum. However, the discovery of the nivalenol (NIV) chemotype of F. graminearum in Louisiana and Arkansas necessitates having resistance in wheat to both chemotypes. The objectives of this research were to quantify resistance of selected winter wheat lines to initial infection and pathogen spread within spikes, to determine whether wheat lines selected for resistance to the DON chemotype also have resistance to the NIV chemotype, and to improve the methods for quantifying resistance to initial infection. A susceptible check (Coker 9835) and 15 winter wheat lines, which are adapted to the southeastern United States and possess diverse sources of head blight resistance, were evaluated for head blight resistance in a series of greenhouse and growth-chamber experiments. Significant levels of resistance to both initial infection and spread within a spike were found among the lines, and lines with resistance to isolates of the DON chemotype had even higher levels of resistance to isolates of the NIV chemotype. Quantifying resistance to initial infection was improved by standardizing the inoculum and environmental conditions. Additional information related to resistance to spread within a spike was obtained by calculating the area under the disease progress curve from 7 to 21 days after inoculation.

scholarly journals Trichothecene Genotype of Fusarium graminearum Isolates from Soybean (Glycine max) Seedling and Root Diseases in the United States

Plant Disease ◽  
2014 ◽  
Vol 98 (7) ◽  
pp. 1012-1012 ◽  
Author(s):  
M. L. Ellis ◽  
G. P. Munkvold
Keyword(s):  
United States ◽  
North America ◽  
Fusarium Graminearum ◽  
Root Rot ◽  
Elongation Factor ◽  
Host Shift ◽  
The United States ◽  
Sensu Stricto ◽  
Head Blight ◽  
The Third

Fusarium graminearum is an economically important pathogen that causes Fusarium head blight of wheat, barley, and oat, and Gibberella ear and stalk rot of maize. More recently, F. graminearum was reported as a soybean seedling and root pathogen in North America (1,5), causing seed decay, damping-off, and brown to reddish-brown root rot symptoms. Type B trichothecene mycotoxins are commonly produced by F. graminearum, which can be categorized into three trichothecene genotypes; those that produce 3-acetyldeoxynivalenol (3-ADON), 15-acetyldeoxynivalenol (15-ADON), or nivalenol (NIV). The 15-ADON genotype is dominant in populations from small grains and maize in North America (4), but the 3-ADON genotype has recently been found (4). F. graminearum was known as a pathogen of wheat and maize in North America for over a century before it was reported as a soybean pathogen. Therefore, we hypothesized that recent reports on soybean could be associated with the appearance of the 3-ADON genotype. The objective of this research was to determine the trichothecene genotype of F. graminearum isolates from soybean in the United States. Thirty-eight isolates from soybean were evaluated. Twenty-seven isolates came from a 3-year survey for Fusarium root rot from 2007 to 2009 in Iowa. Other isolates (Ahmad Fakhoury, Southern Illinois University, Carbondale) were collected from soybean seedlings during a multi-state survey in 2012, and included three isolates from Illinois, three from Indiana, and five from Nebraska. Species identification and lineage of F. graminearum were confirmed by sequencing the translation elongation factor gene (EF1-α) using EF-1H and EF-2T primers. A maximum likelihood analysis of the EF1-α, including voucher strains from nine lineages of F. graminearum (2), placed all 38 isolates into lineage 7, F. graminearum sensu stricto (representative GenBank accessions KJ415349 to KJ415352). To determine the trichothecene genotype of each isolate we used three multiplex PCR assays. The first two assays targeted a portion of trichothecene biosynthesis genes Tri3 and Tri12 (4), while the third assay targeted portions of the Tri3, Tri5, and Tri7 genes (3). The PCR for the first two assays was conducted as described by Ward et al. (4) using four sets of primers: 3CON, 3NA, 3D15A, and 3D3A; and 12CON, 12NF, 12-15F, and 12-3F for the Tri3 and Tri12 genes, respectively. The PCR for the third assay was conducted as described by Quarta et al. (3) using the following primers: Tri3F971, Tri3F1325, Tri3R1679, Tri7F340, Tri7R965, 3551H, and 4056H. The amplification products were analyzed by gel electrophoresis. All 38 isolates produced amplicons consistent with the 15-ADON genotype; ~610 and 670 bp for the Tri3 and Tri12 genes, respectively (4), and two amplicons of ~708 and 525 bp for the Tri3/Tri5 genes (3). Our results indicated that the dominant trichothecene genotype among isolates of F. graminearum from soybean is 15-ADON, and the introduction of 3-ADON isolates does not explain the recent host shift of F. graminearum to soybean in North America. To our knowledge, this is the first assessment of trichothecene genotypes in F. graminearum populations from soybean from the United States. References: (1) K. E. Broders et al. Plant Dis. 91:1155, 2007. (2) K. O'Donnell et al. Fungal Gen. Biol. 41:600, 2004. (3) A. Quarta et al. FEMS Microbiol. Lett. 259:7, 2006. (4) T. D. Ward et al. Fungal Gen. Biol. 45:473, 2008. (5) A. G. Zue et al. Can. J. Plant Pathol. 29:35, 2007.

scholarly journals Nivalenol-Type Populations of Fusarium graminearum and F. asiaticum Are Prevalent on Wheat in Southern Louisiana

2011 ◽  
Vol 101 (1) ◽  
pp. 124-134 ◽  
Author(s):  
Liane Rosewich Gale ◽  
Stephen A. Harrison ◽  
Todd J. Ward ◽  
Kerry O'Donnell ◽  
Eugene A. Milus ◽  
...  
Keyword(s):  
United States ◽  
North Carolina ◽  
Fusarium Graminearum ◽  
Gulf Coast ◽  
Pcr Primers ◽  
The United States ◽  
Sensu Stricto ◽  
Head Blight ◽  
Trichothecene Mycotoxin ◽  
Southern Louisiana

U.S. populations of the Fusarium graminearum clade cause head blight on wheat and barley and usually contaminate grain with the trichothecene mycotoxin deoxynivalenol (DON). Recently, however, individual nivalenol (NIV)-type isolates from the United States were described that belonged to either the newly described species F. gerlachii or the genetically distinct Gulf Coast population of F. graminearum sensu stricto (s.s.). Here, we describe the discovery of NIV-type F. graminearum s.s. populations that were found in high proportion (79%) among isolates from small-grain-growing regions of Louisiana. We genotyped 237 isolates from Louisiana with newly developed polymerase chain reaction (PCR) restriction fragment length polymorphism markers and multiplex PCR primers that distinguish among the three trichothecene types: the two DON types (15ADON and 3ADON) and NIV. These isolates were compared with 297 isolates from 11 other U.S. states, predominantly from the Midwest. Using Bayesian-model-based clustering, we discovered a southern Louisiana population of F. graminearum s.s. that was genetically distinct from the previously recognized pathogen population in the Midwest (MW15ADON population). Population membership was correlated with trichothecene type. Most isolates from the southern Louisiana population were of the NIV type, while the majority of the isolates from the Midwest were of the 15ADON type. A smaller proportion of isolates from Louisiana belonged to the previously described Gulf Coast population that was mostly of the 3ADON type. The NIV type was also identified in collections from Arkansas (12%), North Carolina (40%), and Missouri (2%), with the collections from Arkansas and North Carolina being small and unrepresentative. F. asiaticum was detected from the two southern Louisiana parishes Acadia and Alexandria. All identified 41 F. asiaticum isolates were of the NIV type. Greenhouse tests indicated that U.S. NIV types accumulated four times less trichothecene toxin than DON types on inoculated wheat. This is the first report of NIV-type populations of F. graminearum s. s. and F. asiaticum in the United States.

scholarly journals Pathogenicity and In Planta Mycotoxin Accumulation Among Members of the Fusarium graminearum Species Complex on Wheat and Rice

2005 ◽  
Vol 95 (12) ◽  
pp. 1397-1404 ◽  
Author(s):  
Rubella S. Goswami ◽  
H. Corby Kistler
Keyword(s):  
United States ◽  
Fusarium Graminearum ◽  
Species Complex ◽  
The United States ◽  
Susceptible Cultivar ◽  
In Planta ◽  
Head Blight ◽  
Fusarium Graminearum Species Complex ◽  
Small Grains ◽  
Species Specific

Fusarium head blight (FHB), or scab, is a destructive disease of small grains caused by members of the Fusarium graminearum species complex, comprised of at least nine distinct, cryptic species. Members of this complex are known to produce mycotoxins including the trichothecenes deoxynivalenol (DON) along with its acetylated derivatives and nivalenol (NIV). In this study, 31 strains, belonging to eight species of this complex and originating from diverse hosts or substrates, were tested for differences in aggressiveness and mycotoxin production. Large variation among strains, both in terms of their aggressiveness and the ability to produce trichothecenes on a susceptible cultivar of wheat was found; variation appears to be a strain-specific rather than species-specific characteristic. While pathogenicity was not influenced by the type of mycotoxin produced, a significant correlation was observed between the amount of the dominant trichothecene (DON and its acetylated forms or NIV) produced by each strain and its level of aggressiveness on wheat. Some isolates also were tested for their ability to infect rice cv. M201, commonly grown in the United States. While tested strains were capable of infecting rice under greenhouse conditions and causing significant amount of disease, no trichothecenes could be detected from the infected rice florets.

Sensitivity of Fusarium graminearum to Metconazole and Tebuconazole Fungicides Before and After Widespread Use in Wheat in the United States

2020 ◽  
Vol 21 (2) ◽  
pp. 85-90 ◽  
Author(s):  
Nolan R. Anderson ◽  
Anna N. Freije ◽  
Gary C. Bergstrom ◽  
Carl A. Bradley ◽  
Christina Cowger ◽  
...  
Keyword(s):  
United States ◽  
Fusarium Graminearum ◽  
Monitoring Program ◽  
Fungal Growth ◽  
The United States ◽  
Head Blight ◽  
Fungicide Sensitivity ◽  
Triazole Fungicides ◽  
Before And After ◽  
The Mean

Fusarium head blight (FHB) caused primarily by Fusarium graminearum, is a major disease of wheat in the United States. FHB is managed in part by applications of demethylation inhibitor (DMI) triazole fungicides during anthesis. The objective of this study was to examine the sensitivity of U.S. populations of F. graminearum to the DMI triazole fungicides metconazole and tebuconazole. Isolates of F. graminearum collected from wheat between 1981 and 2014 were tested for fungicide sensitivity using mycelial growth assays to determine the effective concentration at which 50% of fungal growth was inhibited (EC50). A total of 45 isolates were tested for metconazole sensitivity and 47 for sensitivity to tebuconazole. Isolates were analyzed in groups based on collection date. Groupings consisted of isolates collected prior to widespread fungicide use in wheat (designated as year 2000) or after fungicides became available for use in wheat. The mean EC50 for isolates collected prior to 2000 was 0.0240 µg/ml for metconazole and 0.1610 µg/ml for tebuconazole. For both fungicides, isolates collected between 2000 and 2014 had significantly higher (P = 0.05) mean EC50 values (mean EC50 = 0.0405 and 0.3311 µg/ml for metconazole and tebuconazole, respectively) compared with isolates collected prior to 2000. Isolate, year, and state of collection all affected the mean EC50 values of isolates collected between 2000 and 2014. A single isolate collected from Illinois in 2012 exhibited EC50 values of 0.1734 µg/ml for metconazole and 1.7339 µg/ml for tebuconazole, indicating reduced sensitivity compared with the mean EC50 of other isolates collected between 2000 and 2014. This study is the first step toward developing a fungicide sensitivity monitoring program for F. graminearum in the United States.

Effectiveness of fungicide seed treatments for preventing seed-to-seedling transmission of Fusarium graminearum under controlled-environment conditions

2009 ◽  
Vol 89 (4) ◽  
pp. 811-821 ◽  
Author(s):  
M R Fernandez ◽  
T K Turkington ◽  
W E May
Keyword(s):  
Fusarium Graminearum ◽  
Plant Tissue ◽  
Seedling Emergence ◽  
Wheat Root ◽  
Crown Rot ◽  
Controlled Environment ◽  
Wheat Seed ◽  
Seed Treatments ◽  
Head Blight ◽  
Infected Seed

Fusarium head blight (FHB) is well established in the eastern prairies, but for the most part it has been absent from western regions, especially under dryland conditions. This has been largely attributed to dry and hot conditions during some years, and the limited occurrence of F. graminearum in the western prairies. It is of importance to prevent the movement of F. graminearum, the most important FHB pathogen in North America, to areas where this pathogen is not commonly found. Three controlled-environment studies, using different Fusarium-infected common and durum wheat seed lots, were conducted to determine the effectiveness of currently registered fungicide seed treatments in improving seedling emergence and plant development, and preventing the growth of F. graminearum from infected seed to plant tissue. Fungicide treatments improved seedling emergence from the most infected seed over the untreated infected control, but most treatments did not improve emergence in the other experiments. Plant growth in the fungicide treatments was either similar to or slower than in the untreated controls. Fusarium graminearum was isolated from discoloured tissue in all treatments and was generally more common in crowns than in subcrown internodes. No fungicide treatment reduced discolouration of plant tissue or percentage isolation of F. graminearum or other Fusarium spp. consistently. We conclude that while currently registered seed treatments might be effective in improving seedling emergence in some infected wheat seed lots, they do not prevent the growth of F. graminearum from seeds to plant tissue. For the western prairies, the use of fungicide seed treatments as a strategy in the prevention of spread of FHB would require that they be effective primarily against F. graminearum. Performance of fungicide seed treatments against Fusarium-infected wheat seed should also be determined under typical growing conditions across the western prairies.Key words: Seed treatments, fungicides, wheat, root rot, crown rot, Fusarium graminearum, Fusarium avenaceum

scholarly journals How Quickly are Road-killed Snakes Scavenged? Implications for Underestimates of Road Mortality

2011 ◽  
Vol 127 (2) ◽  
pp. 184-188 ◽  
Author(s):  
BRETT A. DEGREGORIO ◽  
THOMAS E. HANCOCK ◽  
DAVID J. KURZ ◽  
SAM YUE
Keyword(s):  
United States ◽  
Population Dynamics ◽  
Community Composition ◽  
The United States ◽  
The Other ◽  
Road Mortality ◽  
Correction Factors ◽  
Significant Extent ◽  
Removal Time ◽  
Maritime Forest

Abstract Annually, millions of snakes are killed on roads in the United States. Because of their potential abundance and ease of collection, many researchers have used road-killed snakes to examine community composition, movement patterns, and population dynamics. However, few previous studies have accounted for snake carcasses that are removed from roads by scavengers. Snake carcasses were placed at randomly selected locations along 2 km of road, one traversing maritime forest and the other surrounded by dune habitat. Carcasses in forested habitat were removed more often (100% vs 40%) and more quickly (8 hr vs 11 hr) than those placed in dune habitat. Half of the carcasses (50%) were removed within eight hours of placement and all carcasses were removed at night. Species and size of carcasses did not affect removal time. Removal time and scavenging intensity of snake carcasses most likely varies across regions and habitats. Furthermore, because scavenging appears to occur quickly and to such a significant extent, it may confound results of studies examining patterns of road-mortality. Thus, investigators that use data from road-killed snakes would benefit from a concurrent investigation of scavenging and application of appropriate correction factors to avoid underestimation of snake mortality.

scholarly journals Fusarium graminearum Possesses Virulence Factors Common to Fusarium Head Blight of Wheat and Seedling Rot of Soybean but Differing in Their Impact on Disease Severity

2014 ◽  
Vol 104 (11) ◽  
pp. 1201-1207 ◽  
Author(s):  
Luca Sella ◽  
Katia Gazzetti ◽  
Carla Castiglioni ◽  
Wilhelm Schäfer ◽  
Francesco Favaron
Keyword(s):  
Fusarium Head Blight ◽  
Disease Severity ◽  
Fusarium Graminearum ◽  
Map Kinases ◽  
Early Stage ◽  
Single Gene ◽  
Crown Rot ◽  
Head Blight ◽  
Soybean Seedlings ◽  
Seedling Rot

Fusarium graminearum is a toxigenic fungal pathogen that causes Fusarium head blight (FHB) and crown rot on cereal crops worldwide. This fungus also causes damping-off and crown and root rots at the early stage of crop development in soybean cultivated in North and South America. Several F. graminearum genes were investigated for their contribution to FHB in cereals but no inherent study is reported for the dicotyledonous soybean host. In this study we determined the disease severity on soybean seedlings of five single gene disrupted mutants of F. graminearum, previously characterized in wheat spike infection. Three of these mutants are impaired on a specific function as the production of deoxynivalenol (DON, Δtri5), lipase (ΔFgl1), and xylanase (Δxyl03624), while the remaining two are MAP kinase mutants (ΔFgOS-2, Δgpmk1), which are altered in signaling pathways. The mutants that were reduced in virulence (Δtri5, ΔFgl1, and ΔFgOS-2) or are avirulent (Δgpmk1) on wheat were correspondently less virulent or avirulent in soybean seedlings, as shown by the extension of lesions and seedling lengths. The Δxyl03624 mutant was as virulent as the wild type mirroring the behavior observed in wheat. However, a different ranking of symptom severity occurred in the two hosts: the ΔFgOS-2 mutant, that infects wheat spikelets similarly to Δtri5 and ΔFgl1 mutants, provided much reduced symptoms in soybean. Differently from the other mutants, we observed that the ΔFgOS-2 mutant was several fold more sensitive to the glyceollin phytoalexin suggesting that its reduced virulence may be due to its hypersensitivity to this phytoalexin. In conclusion, lipase and DON seem important for full disease symptom development in soybean seedlings, OS-2 and Gpmk1 MAP kinases are essential for virulence, and OS-2 is involved in conferring resistance to the soybean phytoalexin.

scholarly journals A Unified Effort to Fight an Enemy of Wheat and Barley: Fusarium Head Blight

Plant Disease ◽  
2012 ◽  
Vol 96 (12) ◽  
pp. 1712-1728 ◽  
Author(s):  
Marcia McMullen ◽  
Gary Bergstrom ◽  
Erick De Wolf ◽  
Ruth Dill-Macky ◽  
Don Hershman ◽  
...  
Keyword(s):  
United States ◽  
Fusarium Head Blight ◽  
Great Plains ◽  
Plant Disease ◽  
Management Strategies ◽  
The United States ◽  
Export Market ◽  
Northern Great Plains ◽  
Head Blight ◽  
Food And Feed

Wheat and barley are critical food and feed crops around the world. Wheat is grown on more land area worldwide than any other crop. In the United States, production of wheat and barley contributes to domestic food and feed use, and contributes to the export market and balance of trade. Fifteen years ago, Plant Disease published a feature article titled “Scab of wheat and barley: A re-emerging disease of devastating impact”. That article described the series of severe Fusarium head blight (FHB) epidemics that occurred in the United States and Canada, primarily from 1991 through 1996, with emphasis on the unparalleled economic and sociological impacts caused by the 1993 FHB epidemic in spring grains in the Northern Great Plains region. Earlier publications had dealt with the scope and damage caused by this disease in the United States, Canada, Europe, and China. Reviews published after 1997 further described this disease and its impact on North American grain production in the 1990s. This article reviews the disease and documents the information on U.S. FHB epidemics since 1997. The primary goal of this article is to summarize a sustained, coordinated, and collaborative research program that was put in place shortly after the 1993 epidemic, a program intended to quickly lead to improved management strategies and outreach implementation. This program serves as a model to deal with other emerging plant disease threats.

Economics as a Public Mission

2019 ◽  
pp. 115-143
Author(s):  
Amy C. Offner
Keyword(s):  
United States ◽  
Political Economy ◽  
Economic Policy ◽  
Latin America ◽  
National Development ◽  
The United States ◽  
Economic Research ◽  
National Economic ◽  
Specialized Form ◽  
National Economic Policy

This chapter focuses on John M. Hunter, the thirty-nine-year-old Illinois native who spoke as director of Colombia's first economic research center and addressed readers of one of Colombia's premier journals of economic research, the Revista del Banco de la República. It also talks about economics in Latin America. During the years after 1945, Colombian universities established freestanding economics programs where none had existed before. There had been men called economists in Colombia for decades; they were brilliant lawyers, engineers, businessmen, and politicians who made national economic policy and taught occasional courses in political economy on the side. But the crisis of the 1930s had inspired a new regard for economic expertise as a specialized form of knowledge, and Colombians set out to create a new kind of economist to steer the state. The invention of economics as an independent discipline, a nineteenth-century process in the United States and much of Europe, was thus a twentieth-century phenomenon in Latin America, born of new visions of national development and spearheaded by renowned men in business and government.

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