Fusarium Head Blight In Barley Research Articles

UDP-glucosyltransferase HvUGT13248 confers type II resistance to Fusarium graminearum in barley.

Fusarium head blight (FHB) of barley (Hordeum vulgare) causes yield losses and accumulation of trichothecene mycotoxins (e.g. deoxynivalenol [DON]) in grains. Glucosylation of DON to the nontoxic DON-3-O-glucoside (D3G) is catalyzed by UDP-glucosyltransferases (UGTs), such as barley UGT13248. We explored the natural diversity of UGT13248 in 496 barley accessions and showed that all carried potential functional alleles of UGT13248, as no genotypes showed strongly increased seedling sensitivity to DON. From a TILLING population, we identified 2 mutant alleles (T368I and H369Y) that, based on protein modeling, likely affect the UDP-glucose binding of UGT13248. In DON feeding experiments, DON-to-D3G conversion was strongly reduced in spikes of these mutants compared to controls, and plants overexpressing UGT13248 showed increased resistance to DON and increased DON-to-D3G conversion. Moreover, field-grown plants carrying the T368I or H369Y mutations inoculated with Fusarium graminearum showed increased FHB disease severity and reduced D3G production. Barley is generally considered to have type II resistance that limits the spread of F. graminearum from the infected spikelet to adjacent spikelets. Point inoculation experiments with F. graminearum showed increased infection spread in T368I and H369Y across the spike compared to wild type, while overexpression plants showed decreased spread of FHB symptoms. Confocal microscopy revealed that F. graminearum spread to distant rachis nodes in T368I and H369Y mutants but was arrested at the rachis node of the inoculated spikelet in wild-type plants. Taken together, our data reveal that UGT13248 confers type II resistance to FHB in barley via conjugation of DON to D3G.

Implications of Crop Rotation and Fungicide on Fusarium and Mycotoxin Spectra in Manitoba Barley, 2017-2019.

Fusarium head blight (FHB) is one of the most important diseases of barley in Manitoba province (western Canada), and other major barley producing regions of the world. Little is known about the Fusarium species and mycotoxin spectra associated with FHB of barley in Manitoba. Hence, barley grain samples were collected from 149 commercial fields from 2017 to 2019, along with information on respective cropping history, and analyzed with respect to Fusarium species spectra, abundance, chemotype composition, and mycotoxin profiles. Fusarium poae was the predominant Fusarium species associated with FHB of barley in Manitoba, followed by F. graminearum, and F. sporotrichioides; F. equiseti and F. avenaceum were also detected but at low levels. F. poae strains with the nivalenol (NIV) chemotype and F. graminearum strains with 3-acetyl deoxynivalenol (3-ADON) and 15-acetyl deoxynivalenol (15-ADON) chemotypes were commonly detected in the barley grain samples. Nivalenol (597.7, 219.1, and 412.4 µg kg−1) and deoxynivalenol (DON) (264.7, 56.7, and 65.3 µg kg−1) were the two most prevalent mycotoxins contaminating Manitoba barley in 2017, 2018 and 2019, respectively. A substantially higher DON content was detected in grain samples from barley fields with cereals as a preceding crop compared to canola and flax. Furthermore, F. poae proved less sensitive to four triazole fungicides (metconazole, prothioconazole+tebuconazole, tebuconazole, and prothioconazole) than F. graminearum. Findings from this research will assist barley producers with improved understanding of FHB threat levels and optimizing practices for the best management of FHB in barley.

Validation of barley 2OGO gene as a functional orthologue of Arabidopsis DMR6 gene in Fusarium head blight susceptibility

Fusarium head blight (FHB) caused by Fusarium graminearum (Fg) is a devastating disease of crops, especially wheat and barley, resulting in significant yield loss and reduced grain quality. Fg infection leads to the production of mycotoxins, whose consumption is toxic to humans and livestock. The Arabidopsis DMR6 gene encodes a putative 2-oxoglutarate Fe(II)-dependent oxygenase (2OGO) and has been identified as a susceptibility factor to downy mildew. We generated site-specific mutations in Arabidopsis At2OGO by CRISPR/Cas9 gene editing. The resulting At2OGO knock-out (KO) mutants display enhanced resistance to Fg in a detached inflorescence infection assay. Expression profiling of defense genes revealed that impairment of At2OGO function resulted in the upregulation of defense genes that are regulated by salicylic acid (SA), jasmonic acid (JA) and ethylene (ET) pathways. Complementation of the At2OGO-KO lines with a barley (cv. Conlon) orthologue, Hv2OGO, restored susceptibility to Fg. This result indicates that the Hv2OGO gene is functionally equivalent to its Arabidopsis counterpart and, hence, may have a similar role in conditioning susceptibility to FHB in barley. These results provide a molecular basis for proposing 2OGO as a plant immunity suppressor in Arabidopsis and potentially in barley plants and establish a rationale and strategy for enhancing FHB resistance in barley.

Headspace Solid-Phase Microextraction GCMS as a Potential In-Situ Method for the Early Detection of Fusarium Head Blight in Barley

The presence of Fusarium head blight on barley impacts beer quality and can have a significant financial impact on the brewing industry. In this work we investigate the use of a portable GCMS instrument combined with a simple headspace solid phase microextraction method as a potential method for the in-situ detection of fungal growth in barley. Four volatile organic compounds (ethyl acetate, 1-pentanol, 2-pentanone, and 2-hexanone) were identified as indicators of fungal contamination. Barley samples were inoculated in-lab and tested over five days. A positive correlation between peak areas of the indicator compounds and ergosterol was obtained. The method was also applied to some naturally grown barley samples. Our preliminary results demonstrate the potential of the method as a means to determine fungal contamination in-situ.

Overexpression of Nepenthesin HvNEP-1 in Barley Endosperm Reduces Fusarium Head Blight and Mycotoxin Accumulation

Fusarium head blight (FHB) causes substantial losses of yield and quality in grains, both in the field and in post-harvest storage. To date, adequate natural genetic resistance is not available for the control of FHB. This study reports the cloning and overexpression of a barley (Hordeum vulgare L.) antifungal gene, nepenthesin 1 (HvNEP-1), in the endosperm of barley grains. Transgenic barley lines overexpressing HvNEP-1 substantially reduced FHB severity and disease progression after inoculation with Fusarium graminearum or Fusarium culmorum. The transgenic barley also showed reduced accumulation of the mycotoxin deoxynivalenol (DON) in grain, far below the minimum value allowable for food. Semi-field evaluation of four HvNEP-1 transgenic lines revealed substantial reduction of FHB severity and progression as compared with the control H. vulgare cultivar Golden promise (GP) plants. Our study demonstrated the utility of HvNEP-1 for the control of FHB in barley, and possibly other grains such as wheat and maize.

Species composition, toxigenic potential and aggressiveness of Fusarium isolates causing Head Blight of barley in Uruguay

Fusarium Head Blight (FHB) is a major constraint to barley production that substantially reduces yield and grain quality. FHB is also a major food safety concern because FHB pathogens contaminate grain with trichothecenes and other mycotoxins. DNA sequence-based analyses and in-vitro toxin assessments were used to characterize the species and trichothecene chemotype composition of FHB pathogens on barley in Uruguay. F. graminearum was the dominant species (89.7%), and three other members of the F. graminearum species complex (FGSC) were identified as FHB pathogens of barley in Uruguay for the first time. Other minor contributors to FHB species diversity included F. poae, F. avenaceum, F. pseudograminearum and an unnamed species from the F. incarnatum-equiseti species complex (FIESC). Most isolates (89.7%) had the 15-acetyldeoxynivalenol (15-ADON) trichothecene type. However, the results expanded the known area of occurrence within Uruguay for the nivalenol (NIV) toxin type, which was observed among isolates from three species of the FGSC, F. pseudograminearum, and F. poae. Isolates with the 3-acetyldeoxynivalenol (3-ADON) or NX-2 toxin types were not observed, although a previously published multilocus genotyping assay was updated to identify NX-2 strains. Analyses of population structure and comparisons with FHB isolates from wheat in Uruguay indicated that F. graminearum constitutes a single genetic population with no evidence of population differentiation related to the sampled hosts. Inter and intraspecific differences were observed in aggressiveness toward four barley genotypes with different levels of resistance to FHB, and in general nivalenol producers were the least aggressive isolates. Sensitivity to metconazole was approximately 10 times higher than was detected for tebuconazole. This is the first report regarding tebuconazole and metconazole sensitivity for Fusarium species causing FHB in barley in Uruguay, and constitutes an important starting point for monitoring temporal or spatial changes in FGSC sensitivity, which is critical to define FHB management practices.

Differential triazole sensitivity among members of the Fusarium graminearum species complex infecting barley grains in Brazil

Fusarium head blight (FHB) is an important disease of small grains and is caused mainly by members of the Fusarium graminearum species complex (FGSC). Barley growers in Brazil rely on fungicide application, especially triazoles, to suppress the disease and limit mycotoxin contamination of grain. Information on triazole sensitivity among FHB pathogens from barley is limited and it is unclear whether sensitivity levels differ among species within FGSC commonly associated with FHB of barley. To address these questions, grain samples of five barley cultivars were obtained from commercial fields at 21 municipalities in northern Rio Grande do Sul state, Brazil, during 2011 season. The incidence of FGSC was evaluated and the species identity and trichothecene genotypes of FGSC isolates were determined using a multilocus genotype assay. Sensitivity to tebuconazole and metconazole was determined based on the effective concentration that reduced 50% of the mycelial growth (EC50) on agar-based media amended with increasing fungicide dosages (0, 0.1, 0.5, 1.0 and 5.0 μg a.i./ml). FGSC-like colonies were detected in 75% of samples at relatively low mean incidence (3.3%). Among 65 FGSC isolates, three species were found: Fusarium graminearum with the 15-acetyl(A)deoxnyvalenol(DON) genotype was the most common (48 isolates) followed by F. meridionale (16 isolates) with the nivalenol (NIV) genotype and one F. austroamericanum isolate with the 3-ADON genotype. Species composition appeared to be influenced by barley cultivar (P = 0.002), with F. meridionale prevailing in MN743 and MN620 and F. graminearum in BRS Caue and BRS Elis. Overall, FGSC isolates were around 4 × less sensitive to tebuconazole (mean = 0.773 μg/ml) compared to metconazole (mean = 0.136 μg/ml). F. graminearum isolates were less sensitive than F. meridionale to tebuconazole, but both were similarly sensitive to metconazole. These results are important to both risk assessment of mycotoxins in barley and the deployment of effective management strategies.

Sustainable system design for gridded, spatio-temporal, agroecosystem forecasting models

Decision support systems able to capitalize on publicly available high resolution datasets have become increasingly valuable to agroecosystem, hydrologic and urban system stakeholders. In this paper we address the common agroecosystem modeling problem of weather-based risk forecasting. We compare storage system designs for an expandable crop disease forecasting system that relies on multiple gridded weather forecast inputs to artificial neural network disease risk models. A traditional relational database management system (PostgreSQL), a NoSQL database system (MongoDB) and a scientific file format version (netCDF) of a single crop disease risk modeling system in one region of the country, for potato late blight in the US Great Lakes region, were designed and compared for speed. To test expandability, another crop disease risk modeling system, for modeling risk of economically significant deoxynivalenol (eDON) accumulation due to Fusarium head blight of barley in the northern US Great Plains, was also created in the three formats. Speeds for the three types of systems were fairly similar. Expandability, which is becoming highly desirable in agroecosystem model design, differed based on designer priorities.

Výskyt fuzariózy klasov jačmeňa na Slovensku

Fusarium head blight and the negative influence of this dangerous disease is current worldwide problem. The aim of this work was the evaluation of incidence and severity of Fusarium head blight of barley according to different pre-crop in different locations of Slovakia. Occurrence of Fusarium head blight (FHB) was documented during two consecutive years in June 2011-2012 under the natural Fusarium infections in fields with spring barley (Hordeum vulgare). Observations were conducted at four different localities in four climatic regions in Slovakia. Incidence and severity of FHB were evaluated at the growth stages early milk to late milk in three replications. Each replication contained 100 spikes, the incidence of FHB was calculated as FHB index. During the observed period, the infestation of affected heads by FHB ranged from 0 - 12.67 %. The average infestation of heads was 5.16 % in 2011 and 5.42 % in 2012 year. Predominance intensity of FHB on infection heads were 5% or less in each locality. Higher FHB infestations were reached at Špačince (2011), Soblahov (2012) with higher precipitation when comparing long-term average. Conversely, the lowest FHB incidence was in locality with lowest precipitation in June (Veľké Úľany – 2011, Špačince – 2012). Important influence in the severity of FHB infection had also crop rotation. The highest FHB incidence was observed in localities where was maize use as a pre-crop (Špačince, 2011 – 12.67 %, Soblahov, 2012 – 11 %).

Evaluation of Fusarium head blight in barley infected by Fusarium graminearum

Fusarium head blight, which is primarily caused by Fusarium graminearum, is a devastating disease in the barley field. A real-time PCR protocol was developed to evaluate the growth of this pathogen in the host plant tissues. All four strains harbored the gene encoding ATP-BINDING CASSETTE TRANSPORTER (FgABC; FGSG_00541) as a single copy within their genomes. Our Southern blot result was identical with the genomic data for F. graminearum strain PH-1. Based on the crossing point (CP) values obtained in our TaqMan real-time PCR analysis, two standard curves describing the relationship among the CP value, FgABC copy number, and amount of fungal DNA were constructed. Chronological enumeration of fungal growth was coincided with the symptom development.

Studies on the control of Fusarium head blight of barley and wheat and mycotoxin levels in grains based on time of infection and toxin accumulation

Fusarium head blight (FHB) caused by several Fusarium species, especially the F. graminearum species complex, once considered a single species [F. graminearum Schwabe, teleomorph: Gibberella zeae (Schwein.) Petch], is a widespread and destructive disease of wheat, barley, and other small-grain cereals. These pathogens infect spikes and reduce grain yield and quality. Moreover, the FHB pathogens produce mycotoxins such as deoxynivalenol (DON) and nivalenol (NIV), which are toxic to humans and other animals. The Japanese government established provisional guidelines for DON content in unpolished wheat grains as 1.1 mg/kg in 2002, and accordingly, an effective control strategy to reduce the risk of mycotoxin contamination in wheat and barley has been strongly needed. In this study, we studied the time of mycotoxin accumulation in developing barley and wheat grains, and on the basis of our findings and on additional field experiments, we determined the optimal timing of fungicide application to effectively reduce mycotoxin levels in barley and wheat. Studies on barley

HEAD BLIGHT OF BARLEY IN SOUTH AFRICA IS CAUSED BY FUSARIUM GRAMINEARUM WITH A 15-ADON CHEMOTYPE

In the past 4 years, the emergence of Fusarium head blight (FHB) of irrigated barley in the Northern Cape Province (NCP) became a concern to the malting and brewing industries, and the food and feed companies in South Africa. This motivated an epidemiological survey whereby 320 single-spored Fusarium isolates were obtained from diseased barley kernels collected in the NCP over 2 consecutive crop years (2008-2009) on two barley cultivars (potential malting varieties) at several locations. A multiplex PCR using previously published species-specific primers was utilized to simultaneously detect the most frequently encountered species of the FHB complex, including Fusarium graminearum, F. culmorum, F. avenaceum and F. poae. For isolates that could not be identified using PCR, further characterization was performed through sequence analyses. Fusarium graminearum (91.9%) was the dominant species, while F. boothii (6.25%), one of the species within the F. graminearum species complex, F. equiseti (1.25%) and F. poae (0.6%) were isolated far less frequently. Within the F. graminearum species complex, most of the isolates (99.7%) belonged to the 15-ADON chemotype. A real-time PCR assay based on SYBR Green technology was used to accurately quantify F. graminearum in barley samples. This is the first report on Fusarium species and their mycotoxin profiles associated with FHB of barley in South Africa.

Quantitative trait loci conferring resistance to Fusarium head blight in barley respond differentially to Fusarium graminearum infection

Fusarium head blight (FHB), primarily caused by Fusarium graminearum, reduces grain yield and quality in barley. Resistance to FHB is partial and quantitatively inherited. Previously, major FHB resistant QTL were detected on barley chromosome 2H Bin 8 and 2H Bin 10, and another QTL for reduced deoxynivalenol (DON) accumulation was identified on chromosome 3H Bin 6. To develop an understanding of the molecular responses controlled by these loci, we examined DON and fungal biomass levels and the transcriptome differences in near-isogenic line (NIL) pairs carrying contrasting resistant and susceptible alleles at these QTL during F. graminearum infection. No overlap was found among the differentially accumulated transcripts of the three NIL pairs, indicating that the response to infection controlled by the resistance alleles at each QTL may be distinct. Transcripts showing differential accumulation between resistant and susceptible NILs were compared to results from previous wheat/barley-F. graminearum studies and integrated into a wheat/barley-F. graminearum interaction model.

Annual Meeting, Winnipeg, Manitoba, 2009

Annual Meeting, Winnipeg, Manitoba, 2009

Investigation of the effect of nitrogen on severity of Fusarium Head Blight in barley

The effect of nitrogen on Fusarium Head Blight (FHB) in a susceptible barley cultivar was investigated using gel-based proteomics. Barley grown with either 15 or 100kgha(-1)N fertilizer was inoculated with Fusarium graminearum (Fg). The storage protein fraction did not change significantly in response either to N level or Fg, whereas eighty protein spots in the water-soluble albumin fraction increased and 108 spots decreased more than two-fold in intensity in response to Fg. Spots with greater intensity in infected plants contained fungal proteins (9 spots) and proteolytic fragments of plant proteins (65 spots). Identified fungal proteins included two superoxide dismutases, L-xylulose reductase in two spots, peptidyl prolyl cis-trans isomerase and triosephosphate isomerase, and proteins of unknown function. Spots decreasing in intensity in response to Fg contained plant proteins possibly degraded by fungal proteases. Greater spot volume changes occurred in response to Fg in plants grown with low nitrogen, although proteomes of uninfected plants were similar for both treatments. Correlation of proteome changes with measurement of Fusarium-damaged kernels, fungal biomass and mycotoxin levels indicated that increased Fusarium infection occurred in barley with low N and suggests control of N fertilization as a possible way to minimise FHB in barley.

Fusarium head blight of barley in China

Fusarium head blight (FHB) is a widespread and destructive disease of barley (Hordeum vulgare) in China. Extensive research on FHB of barley has been conducted in China over the past 50 years, but most of the research publications are written in Chinese and are not accessible to readers outside China. At least 16 Fusarium species pathogenic to barley have been identified in China, with F. graminearum (teleomorph Gibberella zeae) considered the primary cause of FHB. Severe FHB epidemics have occurred since 1952, particularly in regions in the lower and middle reaches of the Yangtze River. The mycotoxins deoxynivalenol, nivalenol, zearalenone, T-2, and fumonisin have been associated with FHB epidemics in barley, and many cases of mycotoxicosis have been reported. An integrated management strategy has been employed to mitigate FHB. Six-row cultivars have mostly been replaced by two-row cultivars in southern China. New barley cultivars are generally short in stature, mature early, and have the potential to withstand rainstorms in early spring. Barley accessions with different levels of resistance to FHB have been identified and used in barley breeding programs in China and elsewhere in the world. Forecasting models with high levels of accuracy have been used for decades to assess the risk of FHB epidemics. Application of fungicides is recommended as a control measure when necessary. Also recommended are cultural practices to reduce the risk of FHB epidemics. If all these control measures fail, decontamination methods that have been developed are employed to save Fusarium -infected barley kernels for use as feed.

Impacts of Crop Production Factors on Fusarium Head Blight in Barley in Eastern Saskatchewan

Fusarium head blight (FHB) in barley (Hordeum vulgare L.) is well established in the eastern Canadian Prairies and appears to be moving westward. A survey of 192 barley crops in eastern Saskatchewan was conducted to determine the impact of agronomic practices on FHB (1999–2002) and Fusarium‐damaged kernels (FDK) (2000–2001). The most common species isolated from spikes and kernels were F. sporotrichioides, F. avenaceum, and F. graminearum, followed by F. poae and F. culmorum Disease tended to be higher under minimum‐till compared with conventional‐ or zero‐till. Fusarium sporotrichioides was favored by a previous cereal crop, whereas F. avenaceum was higher after a pulse crop, and F. graminearum decreased after a pulse but not an oilseed crop. The latter two pathogens were also more prevalent after diversified cropping sequences than after two cereal crops. Summer fallow, or summer fallow alternated with cereals, decreased FDK. Previous glyphosate (Group 9 herbicides) use was associated with increased infection by all Fusarium spp., whereas Group 1 herbicides were associated with increased infection by F. poae and F. sporotrichioides Effects of both herbicide groups depended on tillage system. Number of previous glyphosate applications was also correlated with FHB caused by F. avenaceum and F. graminearum We concluded that in eastern Saskatchewan, barley grown under minimum‐till where glyphosate had been sprayed and following diversified cropping sequences would sustain the greatest damage due to FHB and FDK caused by F. avenaceum and F. graminearum

ELISA Analysis for Fusarium in Barley: Development of Methodology and Field Assessment

Evaluating Fusarium head blight (FHB) involves inoculating barley (Hordeum vulgare L.) with Fusarium graminearum Schwabe [teleomorph Gibberella zeae (Schwein.) Petch] followed by visual observation of disease and analysis for deoxynivalenol (DON). Disease symptoms and DON are not always correlated because both are affected by environmental variables. The objective of this study was to develop an enzyme‐linked immunosorbent assay (ELISA) for quantification of FHB in barley. Antibodies to F. graminearum were tested for reaction with other Fusarium spp. Antibodies from cell line IF8 reacted with Fusarium spp. tested, but not other Ascomycota. The ELISA method was developed using seed lots with no, low, and high levels of DON. Quantity of seed, volume of extraction buffer, and agitation time were tested and Fusarium quantified with ELISA. Five genotypes each for high, medium, and low ELISA values were selected from a field experiment using a doubled‐haploid mapping population in 2003. The lines were grown in 2004 and scored for FHB, DON, and ELISA. ELISA had lower error than FHB or DON. Lines selected for low, medium, and high ELISA in 2003 had low, medium, and high ELISA values in 2004. ELISA and DON were correlated in both field experiments (r = 0.51). ELISA and DON were correlated (r = 0.71) in samples selected from grain elevators in 1993 through 2003 indicating naturally occurring Fusarium spp. outside the B clade had no effect on the performance of the ELISA analysis.

Diversity and prevalence of Fusarium species from Quebec barley fields

Fusarium head blight (FHB), a fungal disease caused by several species of Fusarium, results in reduced yields and grain quality in barley (Hordeum vulgare). Various mycotoxins are produced by the Fusarium spp., and these can be very harmful to animals and humans. As a basis for progress in devising future management strategies for FHB in barley, it is necessary to identify the most common causal Fusarium spp. in Quebec and to determine whether their prevalence varies over space and time. In this study, we identified the Fusarium spp. present in 144 samples of barley seed harvested in 12 administrative regions of Quebec in 2000, 2001, and 2002. In total, 20 species of Fusarium were identified on the basis of the morphological characteristics of the fungal isolates. Overall, infection levels (expressed as percentages of infected kernels) were 8.3%, 8.2%, and 36.3%, respectively, for 2000, 2001, and 2002. Three species were responsible for most of these infections: F. graminearum (41.0% of infected seed), F. poae (23.2%), and F. avenaceum (15.8%). A fourth species, F. sporotrichioides, although less prevalent (5.6%), was found in each of the three years. On the basis of the broader sampling done in 2002, it appears that geography influenced the species of Fusarium that predominated. Fusarium graminearum was more prevalent in the southernmost regions, F. avenaceum in the easternmost regions, and F. poae in the regions located on the north shore of the St. Lawrence River. This information should prove helpful in devising the best strategies for effective management of FHB in Quebec.

The Fourth Canadian Workshop on Fusarium Head Blight / Quatrième colloque canadien sur la fusariose

The Fourth Canadian Workshop on Fusarium Head Blight / Quatrième colloque canadien sur la fusariose