Template:NAU-CHINA/background
Guardians of
Wheat-Background
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What is
Fusarium head blight?
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Fusarium head blight (FHB) or wheat scab is a fungal disease that affects wheat, barley, oats, corn, and many grasses. This disease results in yield reductions and introduces mycotoxins into the crop that pose serious health risks to humans and animals consuming contaminated grain or corn products.
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Consequently, when cereal plants are infected with these fungi, there is a risk that grain may become contaminated with Fusarium mycotoxins and that these may subsequently be transferred to compound feeds.
The FHB fungus may produce mycotoxins, including deoxynivalenol (DON) and zearalenone (ZEN), that when ingested, can adversely affect livestock and human health.
Deoxynivalenol (DON)
Humans consuming flour made from wheat contaminated with DON will often demonstrate symptoms of nausea, fever, headaches, and vomiting
DON is sometimes called vomitoxin because of its deleterious effects on the digestive system of swine and other monogastric animals. DON disrupts normal cell function by inhibiting protein synthesis.
DON contamination is measured in parts per million (ppm). DON levels in FHB-infected wheat are frequently quite high (>20 ppm).
The USDA recommends that DON levels in human foods not exceed 1 ppm.
Zearalenone (ZEN)
ZEN acts like artificial oestrogen agonists by competitively binding to the oestrogen receptor causing changes in external and internal genitals and reproduction disorders
Diseased spikelets on an infected grain head die and bleach prematurely.Healthy spikelets on the same head retain their normal green color. Over time, premature bleaching of spikelets may progress throughout the entire grain head. If infections occur on the stem immediately below the head,the entire head may die. As symptoms progress, developing grains are colonized causing them to shrink and wrinkle. Often, infected kernels have a rough, sunken appearance, and range in color from pink or soft gray, to light brown.
Fusarium head blight in wheat
How can we save a wheat crop from
Fusarium head blight?
At present, there are three main methods to control wheat scab: cultivate resistance breeding, chemical control, and biocontrol agent-antagonistic bacteria.Fungicides are available for control of Fusarium head blight.However, there exist shortcomings and potential damage in chemical methods.
| Advantage | Disadvantage | |
|---|---|---|
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Resistance breeding |
Safe Environmental friendly |
Losing the most desir- -able Characteristics easily (multiple resist- -ance genes); High cost；Long experim- ental period |
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Chemical control |
Convenient Efficient |
Pesticide resistance; do harm to human and other organisms poten -tially Soil pollution |
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Biocontrol agent |
Efficient |
High-cost;Instability； potential risk |
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Table 1 The results of detection of carbendazim-resistance ( Fusarium graminearum ) from 2012 to 2016 |
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|---|---|---|
| Year |
The proportion of carbendazin- resistant strains(%) |
Range% |
| 2012 | 24.35 | 17.41~28.74 |
| 2013 | 28.67 | 7.05~57.14 |
| 2014 | 40.55 | 33.33~57.14 |
| 2015 | 47.37 | 35.6~58.21 |
| 2016 | 55.71 | 50.13~60.65 |
The importance of
controlling wheat scab
Wheat plays an important role in worldwide food culture. In 2010, wheat became the world's second largest production food crop, higher than rice. More than 70% of the world's arable land to grow food is covered by the wheat. Every month, there is more than an area in the world to harvest wheat. A great number of foods are made from wheat, such as noodles , bread, edible starch, vermicelli, cakes, moon cakes, puffed food, biscuits, instant noodles,Lantern and so on.Obviously , the equality of wheat links to the equality of our life.
| Year |
Area of wheat (*10^4 are) |
actual loss |
recovery |
final loss |
|---|---|---|---|---|
| 2012 | 318.16 | 890.64 | 736.17 | 1626.81 |
| 2013 | 326.83 | 0.01 | 445.68 | 445.69 |
| 2014 | 325.50 | 10.86 | 481.27 | 492.12 |
| 2015 | 326.84 | 80.30 | 513.28 | 593.56 |
| 2016 | 327.16 | 11.62 | 417.92 | 429.54 |
| total | 993.41 | 2594.30 | 3578.71 |
China is one of the countries suffering from the wheat scabs. Wheat scabs affected areas are about 7.5 million hectares,accounting for the 1/4 of the total area of wheat. The annual loss of damage caused by scabs is about 2 million to 3 million Ton. The annual cost of prevention and treatment of scabs is as high as 200 million RMB.
Mycotoxins as a threat
to human health
FHB produces various mycotoxins,notably deoxynivalenol (DON) and zearalenone (ZEN) that are toxic to humans and animals, respectively.Eating infected wheat can cause dizziness,fever,
nausea,diarrhea and other acute poisoning symptoms, will even damages immunity and fertility in a severe degree. The two toxins directly pose crippling threats on the human and animal health. With its property of being thermo-tolerant，it will not be denatured even at 126 ℃. Study shows it still shows great toxicity and fatality after incubating at 126 ℃ for 90 minutes.
