New GM rice

Transgenic rice will become resistant to pests without compromising yield

Sofia Dolotovskaya, N+1

Akitai scientists have proposed a mechanism that allows epigenetically regulating the balance between disease resistance and yield in transgenic rice. Article by Deng et al. Epigenetic regulation of antagonistic receptors confers rice blast resistance with yield balance is published in the journal Science (Epigenetic regulation of antagonistic receptors confers rice blast resistance with yield balance).

Genetic modifications of agricultural crops are most often used to make them resistant to insect pests or herbicides that destroy weeds. However, the introduction of a large number of copies of resistance genes into the genome of plants often reduces their yield. Reducing the number of copies, in turn, reduces stability. The authors of the new article described a previously unknown molecular mechanism that provides stability to one of the varieties of transgenic rice while maintaining high yields. In the future, this mechanism can be used to create other varieties of transgenic plants that are resistant to the disease while maintaining high yields.

The study used transgenic rice Gumei 4 (GM4), resistant to rice pyriculariasis – one of the most dangerous diseases of rice, which is caused by fungi Pyricularia oryzae. Unlike many other transgenic varieties of rice, GM4 also retains high yields. Disease resistance is provided by the Pigm locus embedded in the rice genome. However, the gene composition of this locus has remained unknown until now.

The authors have shown that the Pigm locus is a cluster of genes encoding nucleotide-binding receptors that provide resistance to fungal infection. The cluster contains two competing types of genes: Pigmrs provide proper resistance, and PigmS prevents PigmR activation, thereby suppressing resistance. At the same time, PigmR causes a decrease in grain size, and PigmS, on the contrary, increases productivity. The competitive interaction of these two genes thus provides a balance between resistance to pyriculariasis and high yield.

At the same time, the expression of PigmS, as it turned out, is regulated epigenetically, due to the methylation of tandem MITE transposons in the promoter region. This allowed the authors to propose a mechanism for regulating PigmS expression: by stimulating or suppressing MITE methylation, it is thus possible to regulate the antagonistic interaction of PigmR and PigmS, increasing or decreasing resistance to pyriculariasis and yield.

Recently, Japanese biologists have obtained transgenic rice, in the grains of which 20 percent less phosphate compounds are stored than in ordinary plants. The cultivation of this rice will reduce the use of fertilizers and, at the same time, improve the digestibility of nutrients.

In the spring of 2016, an official report on genetically modified (GM) crops was published in the United States. Its authors analyzed more than 900 scientific studies and came to the conclusion that GM crops are not only not harmful, but can be useful for humans. A month later, the Russian State Duma adopted a law banning the cultivation and breeding of GM organisms in the country. The exception is made only for scientific experiments.

Portal "Eternal youth" http://vechnayamolodost.ru  06.02.2017