After decoding the genome of wild distant relative
wheat Chinese scientists have identified the gene that gives the grains
resistance to the fungus Fusarium.
It turned out that the Fhb7 gene encodes an enzyme that neutralizes the toxins of the fungus
by their chemical modification. Cross-breeding with a distant relative and transfer
genetic locus helped get wheat resistant to Fusarium,
stated in the article in Science.
Ascomycetous fungi of the genus Fusarium
— common pests of agricultural crops. In particular, Fusárium gramineárum parasite on wheat, causing Fusarium
ear. In the process of life not just the fungus destroys the grain, but also produces
toxins from the group of trichothecenes, which, in particular, inhibit protein synthesis.
These toxins are poisonous to humans and animals and make the surviving grain
unsuitable for use in food.
Although there are resistant to Fusarium varieties
wheat, they are not so widespread. In some regions of Fusarium head blight still affects up to 15
percent of wheat crop. Resistant varieties were received including by
interbreeding with wild relatives of wheat, but by what mechanism
provides protection from fungus, was still unknown.
Chinese scientists from
agricultural University of Shandong have identified a gene of resistance to
Fusarium and deciphered the mechanism of this resistance. The researchers have read and collected
the genome of the wild relative of cultivated wheat Thinopyrum elongatum, which has
natural resistance to fungus. Analyzing the genome, scientists have suggested that it
is provided by the presence Fhb7 gene, encoding the enzyme glutathionetransferase. Judging
this gene from another fungus parasitic herbaceous plants, Epichloe aotearoae,
and got it by horizontal transfer. In the plant Kingdom like gene
no one could not be found.
Using directed and random mutagenesis of the gene Fhb7
was able to confirm that it protects the plants from Fusarium. Pouring
resistant plants trichothecenes and analyzing with the help of chromatography
the resulting compounds, the researchers found that the enzyme modifies the epoxy group
toxins hanging on them a molecule of glutathione. After that trichothecenes are losing
Transfer to a wheat genetic locus containing Fhb7, when
help dalnorechensk crosses with Thinopyrum,
really made the grain not only resistant to Fusarium head blight of, but also to
root rot, caused by the related fungus Fusárium pseudogramineárum, as well as to fungus Fusárium
asiaticum — the main causative agent of head blight of wheat in South China. In this case
the researchers noted that the yield of cereal after hybridization has not fallen.
Although in this work the researchers
used traditional methods of obtaining resistant varieties of wheat, that is
the crossing, according to biotechnologists, agriculture has long been waiting for the appearance of
genetically modified wheat varieties, resistant to diseases. The
at least, on the market, no such variety has not yet hit. Why this happens, read
in our material “without the bread”.