Molecular biologists from the United States have created a new rice variety that can produce seeds without the participation of a second plant, in fact, copying itself. The prospects for the use of such "clones" were described in the journal Nature.
Today, among scientists there is no unambiguous idea of when and where the domestication of rice took place. Genetic studies show that rice was “tamed” by the ancient inhabitants of Southeast Asia or southern China about 9-13 thousand years ago, but the first unequivocal archaeological evidence of its existence falls on a much later era, 4.5-4 thousand years ago.
All this time, farmers, and then breeders, dreamed of breeding rice that would not need male and female plants for reproduction. This would simultaneously make it independent of pollinators, and would make it possible to create "stable" varieties of this cereal, the properties of whose seeds would not depend on the qualities of an unknown "partner" for reproduction.
Interestingly, many plants in the wild have a similar property, which scientists call apogamogony. On the other hand, no other cultivated plant has this quality, which forces breeders to virtually re-create hybrid varieties of wheat, tomato, rice and other plants every season.
Sudaresan and his colleagues were able to realize this dream for the first time by studying how different genes work in the "male" pollen and the "female" ovule. They were interested in those parts of DNA that were active only in one of the types of plant germ cells, as well as what functions they performed.
By turning these genes on and off, the scientists discovered that one of these regions, the "male" BBM1 gene, played the role of a kind of "trigger" that triggers the program for the development of the ovule into a full-fledged rice embryo.
Guided by this idea, the scientists modified the DNA of one of the popular rice varieties in such a way that BBM1 was included not only in male, but also in female germ cells. Additionally, scientists changed their genome in such a way that the formation of pollen and ovule did not lead to the fact that the number of chromosomes in them was halved.
This allowed such cells to independently transform into a full-fledged embryo without requiring fertilization with another type of gamete. At the same time, interestingly, rice has not lost the ability to reproduce sexually. He gave healthy offspring, if the pollen had time to fertilize the ovule before it turned into another "clone".
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Comparison of the DNA of different plant generations showed that their genomes were absolutely identical to each other in 30% of cases. In the near future, biologists plan to bring this figure to 100%, and find a way to make the "clones" form endosperm, grain pulp, without the participation of pollen.
