scholarly journals Comparative Mycotoxin Profiles of Gibberella zeae Populations from Barley, Wheat, Potatoes, and Sugar Beets

2008 ◽  
Vol 74 (21) ◽  
pp. 6513-6520 ◽  
Author(s):  
Rishi R. Burlakoti ◽  
Shaukat Ali ◽  
Gary A. Secor ◽  
Stephen M. Neate ◽  
Marcia P. McMullen ◽  
...  

ABSTRACT Gibberella zeae is one of the most devastating pathogens of barley and wheat in the United States. The fungus also infects noncereal crops, such as potatoes and sugar beets, and the genetic relationships among barley, wheat, potato, and sugar beet isolates indicate high levels of similarity. However, little is known about the toxigenic potential of G. zeae isolates from potatoes and sugar beets. A total of 336 isolates of G. zeae from barley, wheat, potatoes, and sugar beets were collected and analyzed by TRI (trichothecene biosynthesis gene)-based PCR assays. To verify the TRI-based PCR detection of genetic markers by chemical analysis, 45 representative isolates were grown in rice cultures for 28 days and 15 trichothecenes and 2 zearalenone (ZEA) analogs were quantified using gas chromatography-mass spectrometry. TRI-based PCR assays revealed that all isolates had the deoxynivalenol (DON) marker. The frequencies of isolates with the 15-acetyl-deoxynivalenol (15-ADON) marker were higher than those of isolates with the 3-acetyl-deoxynivalenol (3-ADON) marker among isolates from all four crops. Fusarium head blight (FHB)-resistant wheat cultivars had little or no influence on the diversity of isolates associated with the 3-ADON and 15-ADON markers. However, the frequency of isolates with the 3-ADON marker among isolates from the Langdon, ND, sampling site was higher than those among isolates from the Carrington and Minot, ND, sites. In chemical analyses, DON, 3-ADON, 15-ADON, b-ZEA, and ZEA were detected. All isolates produced DON (1 to 782 μg/g) and ZEA (1 to 623 μg/g). These findings may be useful for monitoring mycotoxin contamination and for formulating FHB management strategies for these crops.

Plant Disease ◽  
2004 ◽  
Vol 88 (7) ◽  
pp. 724-730 ◽  
Author(s):  
S. A. Pereyra ◽  
R. Dill-Macky ◽  
A. L. Sims

Survival and inoculum production of Gibberella zeae (Schwein.) Petch (anamorph Fusarium graminearum (Schwabe)), the causal agent of Fusarium head blight of wheat and barley, was related to the rate of wheat (Triticum aestivum L.) residue decomposition. Infested wheat residue, comprising intact nodes, internodes, and leaf sheaths, was placed in fiberglass mesh bags on the soil surface and at 7.5- to 10-cm and 15- to 20-cm depths in chisel-plowed plots and 15 to 20 cm deep in moldboard-plowed plots in October 1997. Residue was sampled monthly from April through November during 1998 and every 2 months through April to October 1999. Buried residue decomposed faster than residue placed on the soil surface. Less than 2% of the dry-matter residue remained in buried treatments after 24 months in the field, while 25% of the residue remained in the soil-surface treatment. Survival of G. zeae on node tissues was inversely related to the residue decomposition rate. Surface residue provided a substrate for G. zeae for a longer period of time than buried residue. Twenty-four months after the initiation of the trial, the level of colonization of nodes in buried residue was half the level of colonization of residue on the soil surface. Colonization of node tissues by G. zeae decreased over time, but increased for other Fusarium spp. Ascospores of G. zeae were still produced on residue pieces after 23 months, and these spores were capable of inducing disease. Data from this research may assist in developing effective management strategies for residues infested with G. zeae.


Plant Disease ◽  
2012 ◽  
Vol 96 (12) ◽  
pp. 1712-1728 ◽  
Author(s):  
Marcia McMullen ◽  
Gary Bergstrom ◽  
Erick De Wolf ◽  
Ruth Dill-Macky ◽  
Don Hershman ◽  
...  

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.


2011 ◽  
Vol 101 (6) ◽  
pp. 687-695 ◽  
Author(s):  
Rishi R. Burlakoti ◽  
Stephen M. Neate ◽  
Tika B. Adhikari ◽  
Sanjaya Gyawali ◽  
Bacilio Salas ◽  
...  

Gibberella zeae, the principal cause of Fusarium head blight (FHB) of barley, contaminates grains with several mycotoxins, which creates a serious problem for the malting barley industry in the United States, China, and Europe. However, limited studies have been conducted on the trichothecene profiles and population genetic structure of G. zeae isolates collected from barley in the United States. Trichothecene biosynthesis gene (TRI)-based polymerase chain reaction (PCR) assays and 10 variable number tandem repeat (VNTR) markers were used to determine the genetic diversity and compare the trichothecene profiles of an older population (n = 115 isolates) of G. zeae collected in 1997 to 2000 with a newer population (n = 147 isolates) collected in 2008. Samples were from across the major barley-growing regions in North Dakota and Minnesota. The results of TRI-based PCR assays were further validated using a subset of 32 and 28 isolates of G. zeae by sequence analysis and gas chromatography, respectively. TRI-based PCR assays revealed that all the G. zeae isolates in both populations had markers for deoxynivalenol (DON), and the frequencies of isolates with a 3-acetyldeoxynivalenol (3-ADON) marker in the newer population were ≈11-fold higher than those among isolates in the older population. G. zeae populations from barley in the Midwest of the United States showed no spatial structure, and all the isolates were solidly in clade 7 of G. zeae, which is quite different from other barley-growing areas of world, where multiple species of G. zeae are commonly found in close proximity and display spatial structure. VNTR analysis showed high gene diversity (H = 0.82 to 0.83) and genotypic diversity but low linkage disequilibrium (LD = 0.02 to 0.07) in both populations. Low genetic differentiation (FST = 0.013) and high gene flow (Nm = 36.84) was observed between the two populations and among subpopulations within the same population (Nm = 12.77 to 29.97), suggesting that temporal and spatial variations had little influence on population differentiation in the Upper Midwest. Similarly, low FST (0.02) was observed between 3-ADON and 15-acetyldeoxynivalenol populations, indicating minor influence of the chemotype of G. zeae isolates on population subdivision, although there was a rapid increase in the frequencies of isolates with the 3-ADON marker in the Upper Midwest between the older collection made in 1997 to 2000 and the newer collection made in 2008. This study provides information to barley-breeding programs for their selection of isolates of G. zeae for evaluating barley genotypes for resistance to FHB and DON accumulation.


Plant Disease ◽  
1999 ◽  
Vol 83 (7) ◽  
pp. 662-666 ◽  
Author(s):  
L. Francl ◽  
G. Shaner ◽  
G. Bergstrom ◽  
J. Gilbert ◽  
W. Pedersen ◽  
...  

The inoculum level of Gibberella zeae on wheat spikes was measured during 1995 and 1996 in nine locations of Canada and the United States prone to Fusarium head blight of wheat. Spikes were exposed after exsertion and until kernel milk or soft dough stage in fields with wheat or corn residue as a source of inoculum; other spikes were exposed in a location remote from any obvious inoculum source; and in 1995 only, control plants remained in a greenhouse. After 24 h, spikes were excised and vigorously shaken in water to remove inoculum. Propagules were enumerated on selective medium and identified as G. zeae from subcultures. Significantly more inoculum was detected from fields in epidemic areas than from remote sites in an epidemic and from fields in nonepidemic areas. The median inoculum level was 20 CFU of G. zeae per spike per day in fields experiencing an epidemic, 4 CFU in locations remote from epidemic fields, 2 CFU in nonepidemic fields, and 1 CFU in locations remote from a source of inoculum in non-epidemic areas. In an epidemic region, inoculum levels near corn stubble reached up to 587 CFU of G. zeae per spike per day, and the median inoculum level of 126 CFU was significantly higher than the median of 13 CFU found near wheat residue. Inoculum was not detected or occurred sporadically during extended dry periods. While inoculum increased during rainy periods, timing of increased levels was variable. Fusarium head blight epidemics were associated with multiple inoculation episodes and coincident wet periods.


Plant Disease ◽  
2012 ◽  
Vol 96 (2) ◽  
pp. 279-284 ◽  
Author(s):  
Piyum A. Khatibi ◽  
Greg Berger ◽  
Shuyu Liu ◽  
Wynse S. Brooks ◽  
Carl A. Griffey ◽  
...  

Fusarium graminearum (teleomorph Gibberella zeae), is a devastating disease of barley (Hordeum vulgare) in the United States. Recent epidemics of FHB in the mid-Atlantic region have underscored the need to develop new commercial varieties of barley that are resistant to FHB and restrict accumulation of the mycotoxin deoxynivalenol (DON). FHB incidence, FHB index, and DON levels of Virginia hulled and hulless barley genotypes were evaluated over five years (2006 to 2010) in FHB nurseries in Virginia. FHB incidence ranged from 22.5% (2010) to 80.1% (2008), and mean DON levels ranged from 0.5 ± 0.4 (2008) to 2.4 ± 2.1 ppm (2010). Barley genotype played a significant role in determining FHB resistance in 2006 to 2009. DON levels were significantly different among barley genotypes in 2007, 2008, and 2009. FHB incidence was positively correlated with FHB index in all 5 years studied. In 2006 and 2010, FHB incidence and index were positively correlated with DON. Early spike emergence resulted in higher FHB incidence and index in 2007, 2008, and 2010. This preliminary work has identified some promising hulled and hulless barley genotypes for targeted breeding and commercialization efforts in FHB nurseries in the future; ‘Eve’ (hulless) and ‘Thoroughbred’ (hulled) ranked among the most FHB resistant genotypes.


2003 ◽  
Vol 93 (7) ◽  
pp. 874-880 ◽  
Author(s):  
Kurt A. Zeller ◽  
Robert L. Bowden ◽  
John F. Leslie

Gibberella zeae (anamorph Fusarium graminearum) causes Fusarium head blight (FHB) of wheat and barley and has been responsible for several billion dollars of losses in the United States since the early 1990s. We isolated G. zeae from the top, middle, and bottom positions of wheat spikes collected from 0.25-m2 quadrats during severe FHB epidemics in a single Kansas (KS) field (1993) and in a single North Dakota (ND) field (1994). Three amplified fragment length polymorphism (AFLP) primer pairs were used to resolve 94 polymorphic loci from 253 isolates. Members of a subset of 26 isolates also were tested for vegetative compatibility groups (VCGs). Both methods indicated high levels of genotypic variability and identified the same sets of isolates as probable clones. The mean number of AFLP multilocus haplotypes per head was approximately 1.8 in each population, but this value probably underestimates the true mean due to the small number of samples taken from each head. Isolates with the same AFLP haplotype often were recovered from different positions in a single head, but only rarely were such apparently clonal isolates recovered from more than one head within a quadrat, a pattern that is consistent with a genetically diverse initial inoculum and limited secondary spread. The KS and ND samples had no common AFLP haplotypes. All G. zeae isolates had high AFLP fingerprint similarity (>70%, unweighted pair group method with arithmetic means similarity) to reference isolates of G. zeae lineage 7. The genetic identity between the KS and ND populations was >99% and the estimated effective migration rate was high (Nm ≈70). Tests for linkage disequilibrium provide little evidence for nonrandom associations between loci. Our results suggest that these populations are parts of a single, panmictic population that experiences frequent recombination. Our results also suggest that a variety of population sampling designs may be satisfactory for assessing diversity in this fungus.


Microbiology ◽  
2009 ◽  
Vol 155 (9) ◽  
pp. 3149-3156 ◽  
Author(s):  
Donald M. Gardiner ◽  
Sheree Osborne ◽  
Kemal Kazan ◽  
John M. Manners

Fusarium graminearum, which causes the globally important head blight disease of wheat, is responsible for the production of the harmful mycotoxin deoxynivalenol (DON) in infected grain. The production of DON by F. graminearum occurs at much higher levels during infection than during axenic growth, and it is therefore important to understand how DON production is regulated in the fungus. Recently, we have identified amines as potent inducers of in vitro DON production in F. graminearum. Although amines strongly induced expression of the key DON biosynthesis gene TRI5 and DON production to levels equivalent to those observed during infection, the timing of this induction suggested that other factors are also likely to be important for the regulation of DON biosynthesis. Here we demonstrate that low extracellular pH both promotes and is required for DON production in F. graminearum. A combination of low pH and amines results in significantly enhanced expression of the TRI5 gene and increased DON production during axenic growth. A better understanding of DON production in F. graminearum would have implications in developing future toxin management strategies.


2020 ◽  
Vol 13 (3) ◽  
pp. 423-439 ◽  
Author(s):  
R. Xia ◽  
A.W. Schaafsma ◽  
F. Wu ◽  
D.C. Hooker

Fusarium head blight (FHB) is a devastating disease to cereal crops worldwide that decreases grain yield, grain quality, and causes mycotoxin contamination. FHB resulted in an estimated $2 billion USD loss in the US between 1993 and 2001, and 520 million Canadian dollars (CAD) in Canada in the 1990s. In the wheat producing areas in Canada and the United States, it is perceived that significant progress has been made to manage FHB, but the economic impact of various innovations has not been quantified. Therefore, the main objective of this study was to assess the economic impact of various practices deployed in the province of Ontario, Canada, on managing deoxynivalenol and improving agronomic performance in winter wheat since an epidemic in 1996. The impacts of four hypothetical FHB management scenarios on total deoxynivalenol (DON) concentration and grain yield were estimated in field experiments that compared old (mid-1990s) and modern era (mid-2010s) production practices. Management scenarios included old and new cultivars varying in susceptibility to FHB, fungicide application and nitrogen rates. These impacts were applied to farm survey data collected in 1996 to estimate farm revenue and profit. A similar economic estimate was conducted for the recent FHB epidemic in 2013. If a modern MR cultivar, a modern fungicide, and the combination were deployed in the epidemic of 1996, farm revenue would have increased by 26-32, 23-36 and 48-60%, and profit increased by 88-157, 42-59 and 165-207 CAD per ha, respectively, depending on the nitrogen rate. In the province of Ontario, up to 68 million CAD of revenue losses could have been avoided in 1996 with the use of modern agronomic and FHB management practices. Our study has quantified some of the major economic advances in managing FHB and DON since 1996, but further research is needed to develop better cultivars and management strategies.


Author(s):  
Bikash Ghimire ◽  
James Buck ◽  
Mohamed Mergoum ◽  
Alfredo D. Martinez-Espinoza

Fusarium head blight (FHB) epidemics on wheat have caused significant yield and economic penalties in the United States since the early 1990s. This report documents FHB epidemics on soft red winter wheat in Georgia in 2018 and 2019. Forty-four wheat fields across 23 counties were assessed for FHB incidence (2019 only), Fusarium-damaged kernel, deoxynivalenol (DON) contamination, and thousand kernel weight. Higher levels of FHB were observed in 2019 compared to 2018. A significant correlation was observed between DON and 7-day pre-anthesis weather variables in 2019. FHB parameters were significantly correlated to post-anthesis weather variables at 10-day in both years and at 20 and 30-day in 2018 suggesting that post-anthesis rather than pre-anthesis weather had a greater impact on FHB in our study. The combination of hours of conducive temperature and relative humidity post-anthesis was consistently correlated with all FHB parameters in both years and could be the best predictor of FHB epidemics. FHB has emerged as the leading threat for soft red winter wheat production in Georgia. Planting moderately resistant wheat cultivars along with in-season management including proper fungicide application, by closely monitoring the national FHB forecasting system, would be the best integrated management strategies for Georgian wheat growers.


2020 ◽  
Vol 116 (11/12) ◽  
Author(s):  
Sinegugu P.N. Shude ◽  
Kwasi S. Yobo ◽  
Nokwazi C. Mbili

Fusarium head blight (FHB), also known as head scab, is a devastating fungal disease that affects small grain cereal crops such as wheat (Triticum aestivum L.). The predominant causal agent, Fusarium graminearum Schwabe (teleomorph: Gibberella zeae (Schwein.) Petch), is ranked the fourth most important fungal plant pathogen worldwide. Apart from yield and quality losses, mycotoxin production can occur from FHB infection, resulting in harmful effects on human and animal health. Some level of disease control may be achieved by using certain fungicides and agronomic practices plus host resistance. In South Africa, there are currently no registered fungicides or bio-fungicides, no resistant wheat cultivars and only limited control is achieved by cultural practices. Because effective disease reduction cannot be achieved by using a single strategy, the integration of multiple management strategies can enhance disease control. We review possible strategies for reducing the risk for FHB infections that are relevant to the context of South Africa and other wheat growing areas in Africa.


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