Multiple metabolic pathways for metabolism of l-tryptophan in Fusarium graminearum

Fusarium graminearum is a plant pathogen that can cause the devastating cereal grain disease fusarium head blight in temperate regions of the world. Previous studies have shown that F. graminearum can synthetize indole-3-acetic acid (auxin) using l-tryptophan (L-TRP)-dependent pathways. In the present study, we have taken a broader approach to examine the metabolism of L-TRP in F. graminearum liquid culture. Our results showed that F. graminearum was able to transiently produce the indole tryptophol when supplied with L-TRP. Comparative gene expression profiling between L-TRP-treated and control cultures showed that L-TRP treatment induced the upregulation of a series of genes with predicted function in the metabolism of L-TRP via anthranilic acid and catechol towards the tricarboxylic acid cycle. It is proposed that this metabolic activity provides extra energy for 15-acetyldeoxynivalenol production, as observed in our experiments. This is the first report of the use of L-TRP to increase energy resources in a Fusarium species.

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Composition of Fusarium species causing natural spike infection in wheat

Acta Agronomica Hungarica ◽

10.1556/aagr.59.2011.3.9 ◽

2011 ◽

Vol 59 (3) ◽

pp. 255-260 ◽

Cited By ~ 1

Author(s):

E. László ◽

B. Varga ◽

O. Veisz

Keyword(s):

Winter Wheat ◽

Fusarium Graminearum ◽

Species Complex ◽

Crop Yields ◽

Fusarium Species ◽

Cereal Crop ◽

Head Blight ◽

Mycotoxin Production ◽

Cereal Grain

Numerous Fusarium species have been associated with the Fusarium head blight (FHB) disease of wheat, barley and other small-grain cereals, reducing worldwide cereal crop yields and, as a consequence of their mycotoxin production in the cereal grain, having an impact on both human and animal health.The year 2010 was extremely favourable for Fusarium head blight pathogens. Over a hundred symptomatic wheat heads were collected from various locations in Hungary. The aim was to determine the diversity of the Fusarium species infecting winter wheat ears. A total of 86 Fusarium spp. were morphologically identified from diseased kernels. F. sambucinum was found to be present in two of the Martonvásár samples. This pathogen had only previously been detected extremely sporadically. The species F. culmorum and F. verticillioides were found at a much lower rate than expected, while none of the isolates were identified as F. poae. On the basis of the results, 95% of the isolates belonged to the Fusarium graminearum species complex.

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Enhanced Resistance to Fusarium graminearum in Transgenic Arabidopsis Plants Expressing a Modified Plant Thionin

Phytopathology ◽

10.1094/phyto-12-19-0447-r ◽

2020 ◽

Vol 110 (5) ◽

pp. 1056-1066 ◽

Cited By ~ 2

Author(s):

Guixia Hao ◽

Matthew G. Bakker ◽

Hye-Seon Kim

Keyword(s):

Transgenic Plants ◽

Fusarium Graminearum ◽

Transgenic Arabidopsis ◽

Hyphal Growth ◽

Marker Genes ◽

Head Blight ◽

Transgenic Expression ◽

Transgenic Arabidopsis Plants ◽

Enhanced Resistance ◽

And Control

The fungal pathogen Fusarium graminearum causes Fusarium head blight (FHB) on wheat, barley, and other grains. FHB results in yield reductions and contaminates grain with trichothecene mycotoxins, which threaten food safety and food security. Innovative mechanisms for controlling FHB are urgently needed. We have previously shown that transgenic tobacco and citrus plants expressing a modified thionin (Mthionin) exhibited enhanced resistance toward several bacterial pathogens. The aim of this study was to investigate whether overexpression of Mthionin could be similarly efficacious against F. graminearum, and whether transgenic expression of Mthionin impacts the plant microbiome. Transgenic Arabidopsis plants expressing Mthionin were generated and confirmed. When challenged with F. graminearum, Mthionin-expressing plants showed less disease and fungal biomass in both leaves and inflorescences compared with control plants. When infiltrated into leaves, macroconidia of F. graminearum germinated at lower rates and produced less hyphal growth in Arabidopsis leaves expressing Mthionin. Moreover, marker genes related to defense signaling pathways were expressed at significantly higher levels after F. graminearum infection in Mthionin transgenic Arabidopsis plants. However, Mthionin expression did not appreciably alter the overall microbiome associated with transgenic plants grown under controlled conditions; across leaves and roots of Mthionin-expressing and control transgenic plants, only a few bacterial and fungal taxa differed, and differences between Mthionin transformants were of similar magnitude compared with control plants. In sum, our data indicate that Mthionin is a promising candidate to produce transgenic crops for reducing FHB severity and ultimately mycotoxin contamination.

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Trichothecenes in Cereal Grains – An Update

Toxins ◽

10.3390/toxins11110634 ◽

2019 ◽

Vol 11 (11) ◽

pp. 634 ◽

Cited By ~ 13

Author(s):

Nora A. Foroud ◽

Danica Baines ◽

Tatiana Y. Gagkaeva ◽

Nehal Thakor ◽

Ana Badea ◽

...

Keyword(s):

Molecular Mechanisms ◽

Fusarium Species ◽

Cereal Grains ◽

Human Consumption ◽

Breeding Strategies ◽

Genetics Of Resistance ◽

Mechanisms Of Resistance ◽

Head Blight ◽

Cereal Grain ◽

Host Tissues

Trichothecenes are sesquiterpenoid mycotoxins produced by fungi from the order Hypocreales, including members of the Fusarium genus that infect cereal grain crops. Different trichothecene-producing Fusarium species and strains have different trichothecene chemotypes belonging to the Type A and B class. These fungi cause a disease of small grain cereals, called Fusarium head blight, and their toxins contaminate host tissues. As potent inhibitors of eukaryotic protein synthesis, trichothecenes pose a health risk to human and animal consumers of infected cereal grains. In 2009, Foroud and Eudes published a review of trichothecenes in cereal grains for human consumption. As an update to this review, the work herein provides a comprehensive and multi-disciplinary review of the Fusarium trichothecenes covering topics in chemistry and biochemistry, pathogen biology, trichothecene toxicity, molecular mechanisms of resistance or detoxification, genetics of resistance and breeding strategies to reduce their contamination of wheat and barley.

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Effects of fungicides applied at anthesis on Fusarium head blight and mycotoxins in wheat

New Zealand Plant Protection ◽

10.30843/nzpp.2002.55.3903 ◽

2002 ◽

Vol 55 ◽

pp. 341-346 ◽

Cited By ~ 3

Author(s):

M.G. Cromey ◽

R.A. Parkes ◽

K.I. Sinclair ◽

D.R. Lauren ◽

R.C. Butler

Keyword(s):

Fusarium Head Blight ◽

Fusarium Graminearum ◽

Field Trial ◽

Fusarium Species ◽

Microdochium Nivale ◽

Yield Losses ◽

Head Blight ◽

Strobilurin Fungicides

Fusarium head blight (FHB) of wheat can cause yield losses of 3070 More importantly affected grain may be less palatable to stock than healthy grain and may contain mycotoxins A field trial in 2000/01 tested several fungicides and fungicide combinations for FHB control FHB incidence was 91 in untreated plots The greatest reduction of FHB incidence grain Fusarium and mycotoxins was achieved with triazoles a benzimadazole or a combination of these Strobilurin fungicides reduced FHB although less effectively than the triazoles and carbendazim but Fusarium incidence was greater in grain harvested from strobilurintreated plots than in grain from untreated plots Combining strobilurin fungicides with fungicides from other groups did not further reduce Fusarium levels in harvested grain Nine Fusarium species and Microdochium nivale were isolated from grain harvested from the trial Fusarium graminearum and F avenaceum were most commonly isolated with F crookwellense and F culmorum also common

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Geographic differences in trichothecene chemotypes of Fusarium graminearum in the Northwest and North of Iran

World Mycotoxin Journal ◽

10.3920/wmj2012.1493 ◽

2013 ◽

Vol 6 (2) ◽

pp. 137-150 ◽

Cited By ~ 17

Author(s):

M. Davari ◽

S.H. Wei ◽

A. Babay-Ahari ◽

M. Arzanlou ◽

C. Waalwijk ◽

...

Keyword(s):

Fusarium Graminearum ◽

Fusarium Species ◽

Elongation Factor ◽

Morphological Characters ◽

Head Blight ◽

The Caspian Sea ◽

Internal Transcribed Spacer Region ◽

North West ◽

The North ◽

North Of Iran

The diversity and prevalence of Fusarium species and their chemotypes on wheat in the North-West and North of Iran was determined. Wheat in these areas is severely affected by Fusarium head blight, with Fusarium graminearum as prevalent species causing 96% of the infections in the North-West and 50% in the Northern provinces. Fungal isolates were identified based on morphological characters and sequences of the internal transcribed spacer region, and parts of translation elongation factor 1-? and RNA polymerase subunit II sequences. Phylogenetic and phylogeographic analyses show little haplotype variation between the F. graminearum strains collected from the different locations, but the isolates differ significantly in their trichothecene chemotypes as determined with a multilocus genotyping assay. F. graminearum strains producing 15-acetyldeoxynivalenol were abundant in Ardabil (North-West of Iran), while in Golestan province (North of Iran) at the other side of the Caspian Sea especially nivalenol producing strains and a variety of other Fusarium species were observed. Strains producing 3-acetyldeoxynivalenol were rarely found in both areas. This is the first detailed study on Fusarium infections in Iranian wheat, showing large differences in prevalent etiological agents and in mycotoxin chemotypes geographically.

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Fusarium and mycotoxin content of harvested grain was not related to tillage intensity in Norwegian spring wheat fields

World Mycotoxin Journal ◽

10.3920/wmj2020.2575 ◽

2020 ◽

pp. 1-14

Author(s):

I.S. Hofgaard ◽

H.U. Aamot ◽

T. Seehusen ◽

H. Riley ◽

R. Dill-Macky ◽

...

Keyword(s):

Spring Wheat ◽

Crop Residues ◽

Fusarium Species ◽

Fungal Growth ◽

Soil Surface ◽

Inoculum Potential ◽

Head Blight ◽

Fusarium Spp ◽

Nutrient Runoff ◽

Cereal Grain

To mitigate the risk of erosion and nutrient runoff, reduced tillage has become more prevalent in Norway. Within within recent decades, there have been some years with relatively high occurrence of Fusarium head blight and mycotoxins in Norwegian cereal grain. This is thought to have been caused by an increased inoculum potential (IP) of Fusarium spp. due to larger amount of crop residues remaining on the soil surface, in combination with weather conditions promoting fungal growth and infection of cereal plants. The objective of this work was to elucidate the influence of different tillage practices on the IP of Fusarium spp. and the subsequent Fusarium-infection and mycotoxin contamination of spring wheat grain at harvest. Tillage trials were conducted at two locations in southeast Norway (Solør and Toten) over three years, 2010-2012. Residues of wheat from the previous year were collected in spring. Fusarium avenaceum and Fusarium graminearum were the most common Fusarium species recorded on wheat straw residues. IP was calculated as the percentage of the residues infested with Fusarium spp. multiplied by the proportion of the soil surface covered with residues. The IP of Fusarium spp. was lower in ploughed plots compared to those tilled with harrowing only. Ploughing in spring resulted in a similarly low IP as autumn ploughing. In contrast, harrowing in autumn generally reduced IP more than did spring harrowing. The mycotoxin levels in the harvested wheat were generally low, except for deoxynivalenol at high levels in Solør 2011. Despite a lower IP of ploughed versus harrowed plots, this was not reflected in the content of Fusarium and mycotoxins in harvested grain. The Fusarium species that dominated in the residues examined in this study were the same as those detected in the harvested grain, supporting the finding that residues are an important source of inoculum.

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Solid substrate bioassay to evaluate the effect of Trichoderma and Clonostachys on the production of zearalenone by Fusarium species

World Mycotoxin Journal ◽

10.3920/wmj2008.x046 ◽

2009 ◽

Vol 2 (1) ◽

pp. 45-52 ◽

Cited By ~ 19

Author(s):

K. Gromadzka ◽

J. Chelkowski ◽

D. Popiel ◽

P. Kachlicki ◽

M. Kostecki ◽

...

Keyword(s):

Crop Residues ◽

Fusarium Species ◽

Solid Substrate ◽

Dual Culture ◽

Ear Rot ◽

Head Blight ◽

Cereal Products ◽

Cereal Grain ◽

Fusarium Pathogens ◽

Significant Yield

Fusarium head blight and maize ear rot are destructive diseases in various cereal production regions, leading to significant yield losses and to the contamination of cereal grain with Fusarium mycotoxins. The mycotoxin zearalenone belongs to the three most important mycotoxins produced by Fusarium species worldwide; moreover, its hormonal oestrogenic activity is higher than its toxicity. The compound also exhibits fungitoxic activity. Toxigenic Fusarium species sporulate on cereal crop residues and produce inoculum to infect the next crop. Reduction of mycotoxin production and pathogen sporulation may be influenced by saprophytic fungal antagonists. Selected Trichoderma and Clonostachys isolates in dual culture bioassays on rice reduced zearalenone, α-zearalenol and zearalenone sulphate production by two isolates of Fusarium graminearum Schwabe and two isolates of F. culmorum (W.G. Smith) Saccardo belonging to three different chemotypes, by over 97%. Two Trichoderma isolates reduced the amount of zearalenone produced by the same four Fusarium isolates by 5-83% in solid substrate bioassays, whereas several Clonostachys isolates reduced the amount of zearalenone by over 96%. Examination of the dynamics of zearalenone reduction showed that the reduction occurred at the fastest rate during the first four days of incubation. Selected non-toxigenic Trichoderma and Clonostachys isolates are candidates for biocontrol agents against toxigenic Fusarium pathogens of cereals and may be useful for decomposition of zearalenone in contaminated cereal grain and cereal products.

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Fusarium Species Pathogenic to Barley and Their Associated Mycotoxins

Plant Disease ◽

10.1094/pdis.1999.83.7.667 ◽

1999 ◽

Vol 83 (7) ◽

pp. 667-674 ◽

Cited By ~ 92

Author(s):

B. Salas ◽

B. J. Steffenson ◽

H. H. Casper ◽

B. Tacke ◽

L. K. Prom ◽

...

Keyword(s):

South Dakota ◽

Fusarium Head Blight ◽

Fusarium Graminearum ◽

Fusarium Species ◽

Red River ◽

Limited Extent ◽

Head Blight ◽

Red River Valley ◽

Fusarium Poae ◽

Respective Species

Epidemics of Fusarium head blight (FHB) occurred on barley in Minnesota, North Dakota, and South Dakota from 1993 to 1998. The Red River Valley region was most severely impacted by the disease based on assessments of FHB severity in grain samples harvested from commercial fields. Fusarium graminearum was the primary pathogen causing these FHB epidemics. It comprised from 62 to 64% of all Fusarium species isolated from infected kernels from 1994 to 1996. Fusarium poae (range of isolation 13 to 20%),F. sporotrichioides (10 to 17%), and F. avenaceum (6 to 10%) also were isolated from barley kernels and were likely involved in causing some FHB infection, but to a very limited extent. All four Fusarium species were pathogenic on barley in inoculation tests conducted in both the greenhouse and the field. Mycotoxin screens were performed on barley spikes inoculated with the respective species in the greenhouse. Spikes infected with F. graminearum contained deoxynivalenol and 15-acetyldeoxyni-valenol; those infected with F. sporotrichioides contained T-2 toxin, HT-2 toxin, and T-2 tetraol; and those infected with F. poae contained nivalenol. Some isolates of F. poae also produced 15-acetoxyscirpenol and scirpentriol. Although F. graminearum and DON are recognized as the primary FHB pathogen and mycotoxin, respectively, in barley, the possible presence of other Fusarium species and mycotoxins should not be overlooked.

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Occurrence, Pathogenicity, and Mycotoxin Production of Fusarium temperatum in Relation to Other Fusarium Species on Maize in Germany

Pathogens ◽

10.3390/pathogens9110864 ◽

2020 ◽

Vol 9 (11) ◽

pp. 864

Author(s):

Annette Pfordt ◽

Simon Schiwek ◽

Anna Rathgeb ◽

Charlotte Rodemann ◽

Nele Bollmann ◽

...

Keyword(s):

Pathogenic Fungus ◽

Fusarium Species ◽

Fusarium Verticillioides ◽

Fusaric Acid ◽

Elongation Factor ◽

Sensu Stricto ◽

Head Blight ◽

Mycotoxin Production ◽

Federal States ◽

Cereal Grain

Fusarium subglutinans is a plant pathogenic fungus infecting cereal grain crops. In 2011, the species was divided in Fusarium temperatumsp. nov. and F. subglutinans sensu stricto. In order to determine the occurrence and significance of F. temperatum and F. subglutinans on maize, a monitoring of maize ears and stalks was carried out in Germany in 2017 and 2018. Species identification was conducted by analysis of the translation elongation factor 1α (TEF-1α) gene. Ninety-four isolates of F. temperatum and eight isolates of F. subglutinans were obtained during two years of monitoring from 60 sampling sites in nine federal states of Germany. Inoculation of maize ears revealed a superior aggressiveness for F. temperatum, followed by Fusarium graminearum, Fusarium verticillioides, and F. subglutinans. On maize stalks, F. graminearum was the most aggressive species while F. temperatum and F. subglutinans caused only small lesions. The optimal temperature for infection of maize ears with F. temperatum was 24 °C and 21 °C for F. subglutinans. All strains of F. temperatum and F. subglutinans were pathogenic on wheat and capable to cause moderate to severe head blight symptoms. The assessment of mycotoxin production of 60 strains of F. temperatum cultivated on rice revealed that all strains produced beauvericin, moniliformin, fusaric acid, and fusaproliferin. The results demonstrate a higher prevalence and aggressiveness of F. temperatum compared to F. subglutinans in German maize cultivation areas.

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Fusarium graminearum populations from maize and wheat in Ontario, Canada

World Mycotoxin Journal ◽

10.3920/wmj2019.2532 ◽

2020 ◽

Vol 13 (3) ◽

pp. 355-366

Author(s):

T. Crippin ◽

V. Limay-Rios ◽

J.B. Renaud ◽

A.W. Schaafsma ◽

M.W. Sumarah ◽

...

Keyword(s):

Fusarium Head Blight ◽

Fusarium Graminearum ◽

Crop Residue ◽

Fusarium Species ◽

Ear Rot ◽

Head Blight ◽

Potential Toxicity ◽

Large Gradient ◽

The Stability ◽

Dominant Genotype

Ontario has suffered widespread epidemics of Fusarium Head Blight or Gibberella Ear Rot roughly every five years since the late 1970s. We undertook a study of the chemotype and genotype of Fusarium graminearum isolated from 1,800 samples of wheat and maize collected across the cereal growing areas over three years. 468 isolates obtained were genotyped and 60 were selected for chemotyping. The dominant genotype has remained the native 15-acetyldeoxynivalenol (15-ADON) population. Approximately 20% of the strains tested were of the native chemotype producing only 15-ADON and one strain producing solely 7α-hydroxy,15-deacetylcalonectrin (3ANX) was observed. The majority of the 15-ADON strains were also capable of producing 3ANX. There was consistent mismatch between chemotype and genotype. This reflects the considerable plasticity in the genes associated with trichothecene biosynthesis documented in several Fusarium species. Although there is a large gradient in climate from southern to eastern Ontario, we did not detect differences in the distribution of the chemotypes. Grain from which strains were isolated for chemotyping were analysed. Approximately half of the 53 samples had >2 mg/kg deoxynivalenol with a maximum of 400 mg/kg and median of 14 mg/kg. 7α-hydroxy,3,15-dideacetylcalonectrin (NX toxin) was detected in three of these samples at an average of 4.5 mg/kg. The stability of the F. graminearum genotype in Ontario can be explained by several factors. Since 1980, the area planted to maize has remained stable, however, the area given to wheat has about doubled. Minimum tillage was rare in 1980 but it is now the norm. Increased crop residue on the soil has greatly increased the biomass of ascocarps that overwinter. Overall, these data demonstrate the need to monitor the mycotoxins in Fusarium populations and for the need to consider the potential toxicity of NX in the feed supply.

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