Spanish biologists have discovered a gene chain linking plant growth genes and "bioclock", and changed its work in the DNA of the cabbage relative so that it began to grow throughout the day and night, according to an article published in the journal Current Biology.
“We found that PRR proteins are responsible not only for the internal clock of plants, but also for the suppression of genes associated with their growth. Now we know how biorhythms affect plant growth, which is extremely important from an agronomic point of view,”says Guiomar Martín from the Center for Agricultural Genomics in Barcelona, Spain.
The genes that determine the circadian rhythms of the human body were identified back in the 90s of the last century. Similar genes are found in the genomes of all plants and animals. These sections of DNA control many processes - the time of sleep and wakefulness, the opening of flowers, the search for food and other periodic phenomena in the life of living beings.
Scientists have been trying for a long time to find DNA regions that link biorhythms and growth genes in the genomes of flora representatives, since their discovery will create “evergrowing” varieties of agricultural crops and solve the problem of hunger. Martin and his colleagues took the first step towards solving this problem by creating the first “variety” of Arabidopsis thaliana, a wild relative of cabbage, with similar DNA modifications.
Arabidopsis, like many other plants, grows in length mainly in the predawn hours, when the moisture level in the soil and in the air is optimal for growth, and almost does not change during the day and in the first half of the night. Its growth is "orchestrated" by the PIF gene and protein, whose molecules decay under the influence of light and accumulate in plant cells during the night. Scientists have been wondering for several years why PIF makes the stem of Arabidopsis grow only in the predawn hours, despite the fact that its concentration becomes high immediately after sunset.
Two years ago, Martin notes, his colleagues at the center discovered an unusual link between the concentration of PIF and another protein, the PRR1 molecule, one of the many components of the plant's bioclock. When the proportion of PRR1 in plant cells was maximally high, the "growth signal" was almost completely absent in them, and vice versa - when PIF molecules were present in the cells, the activity of the "bioclock" was maximally reduced.
Using the findings of colleagues, Martin and his team tried to figure out which gene chains are controlled by both PIF and PRR1, and tried to find them by observing changes in the level of activity of different genes at different times of the day.
As it turned out, only one gene, CDF5, is responsible for the growth of the Arabidopsis stem, whose work stimulates PIF and suppresses PRR1 and a number of other proteins and genes associated with the functioning of plant biorhythms. When scientists changed the structure of CDF5, Arabidopsis began to grow throughout the day, due to which the stem length of such a GMO plant was about 1.5-2 times longer than that of its wild relatives.
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Geneticists suggest that bioclock controls the work of other genes in a similar way, which are responsible for the growth of stems, roots, fruits and flowers. Modifying them will increase crop yields and make flora a more attractive source of biomass for fuel and chemical production.