Genetically modified crops

Scientists have increased the yield of plants by deceiving their defense mechanisms

Julia Korowski, XX2 century

Researchers from the University of Illinois at Urbana-Champaign (UIUC), the Institute of Plant Genetics of the Polish Academy of Sciences (Instytut Genetyki Roślin Polskiej Akademii Nauk) and the University of California at Berkeley (The University of California, Berkeley) increased plant yields by increasing the production of three proteins that are involved in the process photosynthesis. The genetically modified tobacco they created weighs 14-20% more than its "traditional" counterparts. The results of the study are published in the journal Science (Kromdijk et al., Improving photosynthesis and crop productivity by accelerating recovery from photoprotection).

Scientists chose tobacco because it is easily modifiable. In the future, they are going to work with food crops. "We don't know for sure whether this approach will work with other cultures, but since we have touched on a universal process that works the same for all cultures, we are sure that it does," says Professor Stephen Long, one of the authors of the study.

The researchers managed to achieve an increase in yield by "deceiving" the protective mechanisms of plants. Just like animals, our green friends can suffer from intense light. "The leaves of a plant that is under bright sunlight absorb more light than they can process," explains Long. "If they can't get rid of the excess of this energy, it will discolor the leaf." To protect themselves, plants change the flow of chemical processes inside the leaves and simply dissipate excess energy as heat. This process is called non–photochemical quenching (hereinafter referred to as NFT). "But when a leaf falls into the shadow of another leaf or a cloud obscures the sun, it can take up to half an hour for the non–photochemical extinguishing processes to stop," the professor adds. "In the shade, the lack of light limits photosynthesis, and besides, NFT wastes light as heat." In 2004, Long and his colleagues calculated how slow "relaxation" after NFT reduces the productivity of culture during the day. It turned out that, depending on the type of plant and temperature, it decreases by 7.5–30%.

In order for the plants to return to their usual state faster, the scientists decided to add additional copies of three genes encoding proteins responsible for "removing protection". More proteins should have accelerated the plant's reaction to the shade. The researchers took these genes from a well–studied model organism – Tal's rhesus - and embedded them in tobacco. After tests in the laboratory and greenhouse, the modified plant was planted in a field near the University of Illinois. After 22 days, they received tobacco that weighed 14-20% more than their unmodified counterparts.

Drawing by Julie McMahon from the University of Illinois at Urbana-Champaign press release
Scientists tweak photosynthesis to boost crop yield – VM

The main question is whether it will be possible to do the same with vegetables or cereals. "Tobacco is grown for the sake of leaves, and they have increased significantly," says Johannes Kromdijk, one of the authors of the study. "But as for agricultural crops, we will need to increase the parts of the plant that we eat – whether it's fruit, seeds or roots." Scientists have already started experiments with rice and corn. They hope that other scientific groups will find a way to "bring plants to life" even faster, which means they will get more biomass. Perhaps the same effect can be achieved without gene transfer between different species. As a rule, plants "turn off" extra copies of their genes, but with the help of CRISPR or another editing technique, scientists could bypass this barrier and work with the genetic material of the species itself.

Portal "Eternal youth" http://vechnayamolodost.ru  21.11.2016